CA2191456A1

CA2191456A1 - Method and apparatus for low temperature deposition of cvd and pecvd films

Info

Publication number: CA2191456A1
Application number: CA002191456A
Authority: CA
Inventors: Robert F. Foster; Joseph T. Hillman; Rikhit Arora
Original assignee: Robert F. Foster; Joseph T. Hillman; Rikhit Arora; Materials Research Corporation; Tokyo Electron Limited
Current assignee: Tokyo Electron Ltd
Priority date: 1994-06-03
Filing date: 1994-11-29
Publication date: 1995-12-14
Also published as: DE69414274D1; US5628829A; EP0763149A1; AU1294795A; US6140215A; DE69414274T2; KR970703446A; JPH10501300A; EP0763149B1; WO1995033868A1; TW335593B

Abstract

Low temperature deposition of CVD and PECVD
films utilizes a gas-dispersing showerhead (36) position within one inch of a rotating substrate. The showerhead is positioned a suitable distance below a gas-dispensing ring (50, 52) such a steady state flow of gas develop, between the ring and showerhead. A cylindrical structure extends between the gas-dispersing ring and a showerhead to contain the gas over the showerhead yielding a small boundary layer over the substrate. The showerhead is biased with RF energy such that it acts as an electrode to incite a plasma proximate with the substrate for PECVD. The cylinder (60) is isolated from the showerhead such as by a quartz insulator ring (62) to prevent ignition of a plasma within the cylinder, or alternatively, the cylinder is fabricated of quartz material. The RF showerhead utilizes small gas-dispersing holes (54) to further prevent ignition of a plasma within the cylinder.

Description

~WO 95133868 2 ~ 31~ ~ 6 PCTIUS94/13614 METEIOD AND APPARATl~S FOR LOW TEMPE~TURE
DEPOSI'IION OF CVD AND PECVD FI~.M~
Field of the Inv~ontj~ln This invention relates to chemical vapor deposition and specifically to methods and ~ which utili7e a unique A~
between a gas- dispensing r~ and a rotating susceptor for more efficient gas u~lization and more ' plasrnas. More ~;r.~ll~, the methods and ~ are y~i.~ul~ly useful for depositing CVD films consaining titanium.
,u .,d of the Inv~ntinn Chemical vapor deposition, or CVD is a commonly used technique for applying material films or layers to a substrate in the formation of integrated circuits. CVD comprises; ~ E various reactant gases into a deposition chamber housing a substrate. The reactant gases mi~ pro~imate the substrate and chemically react at the sur~ace of the substrate. One or more reactant products from the chemical reactions deposit upon the substrate surface and form a film.

WO 95/33868 21 9 ~ ~ S 6 PCTIUS94/13614 ~
--2-- ~
One form of CVD i~s,"~ i 1 ' ' chemical vapor deposition or PECVD. In PECVD, one or more of the reactant gases are e~cited into a piasrna such as by being e~pose(i to RF or ~.fi. ~u.. ~ elec~l energy. The p~asma includes various activated particles of tne gas or gases.
The e~cited plasma is mi~ed with other reactant gases, and tne plasma supplies energy to the chemical reaction between the various gases to deposit a film on a substrate.
As may be rr ~ the flow of the reactant gases to the substrate surface and to the plasma is important to ensure proper deposition of films in both CVD and PECVD. Preferably, the flOw of the plasma gases to thc e~cited plasma in PECVD, in addition to the flow of the other reactant gases to the subst~ate surface are ur~iform to promote uniform deposition of the desired film.
In some CVD ' , the reactant gases are introduced at yl~ ' ' flow ratcs and evacuaterd at similar ratcs to cnsure that the reactants are propelled in sufficieM densities to react and form the desired fiim. Generally, thc reactant gases are introduced above a substrate, such as by a gas ring or halo, and travel du...~udly to the substrate at rt, .1. 1.~ flow rates. Upon reaching the substrate, the gases mi~ and react to form a film and any remaining gases are e~hausterd such as by a vacuum system. In such CVD t~hni1u~ there is usually a stagnant lay betwe~n tne gas flow of the mi~ed reactant gases and the substratc sur~ce where very small densities of reactants are present. Such a stagnant layer is referred to as a boundary layer. When t~e boundary layer is large, an ~WO 9S/33868 21~ l q ~ 6 PCT/US94/13614 _3 I,lr amount of the reactant gases may bypass the substrate and be e~hausted from the reaction chamber without reacting. This is wasteful, and therefore costly. It is prefe~ble to have a boundary layer as thin and flat as possible so that a useful density of the gas reactants used in tbe chemical reaction are available at the substrate surface and do not bypass the substrate to be e~hausted, unreacted, out of the chamber.
One way of acbieving a thin boundary layer at the substrate is to introduce the reac~ant gases under matched flow conditions. Matched flow of reactant gases is achieved when the outward volume of gas flowing pa~allel to and over the flat surface of the substrate is ~ the same as the input volume of gas flowing generally downward and ~ to the substr~te surface. With low gas flow rates, matched flow can usually be readily achieved; however, with higher gas flow rates, the reactant gases at the substrate do not flow outwardly over the surface of the substrate rapidly enough, and hence, turbulence and baclcflow of the downward gas flow results.
One alternative for reducing such bac~flow and turbulence at increased input gas flow rates is to rotate the substrate on a rotatirlg susceptor.
An e~ample of a suitable rotating susceptor is utilized within the Rotating Dislc Reactor available from Materials Research Cn~rn~nnn (MRC) of Phoeni~, Arizona. A rotating susceptor spins the substrate and creates a downward and outward pumping action which draws the reactant gases to the surface of the substrate and outwardly over the surface. The pumping action creates a more rapid outward flow of the gases over the substrate to allow a higher downward gas flow rate without bacldlow and h~ on~- Preferably, the wafer is O O ~ C G ~. ~ C. C
wo ss/33s6s ~!1 g ~ 4 5 6 ` ` ~ PCltUSg4R3614 r ~

ratated at a speed which achieves matched flow, i.e., where the downward flaw rate is ~uaL ta the ~utward flow rate. Matched reactant gas flow using a ratating susceptor ensures that a suitably thin boundary ~ayer of reactarlt gas is present for uniform deposiion of a film.
While the use of a rotattng susceptor allows greater gas input flow rates, it has generally been found that thc vdocity profile of the reactant gases pumped by the susceptor should be fully devdoped before the gases reach the ratatLng substrate surface in order to obtain a uniform flow over the substtate and thus uniform deposiion on the substtate. That is, the velocity of the incoming gas flow a3 measured across the flow path should reach a steady state. To achieve a steady state flow using current~y available CVD
cl3C~ l30Qop~
at useful deposiion pressures (e g. fro~ to 100 Torr)), it has been necessary to space the gas r~ng and gas-dispersing allu _ ' ' or other I CO ~r~
gas input device A I ~ (4) inches) or more from the surface of the rotrting substrate. While en~ancing the steady state flow of the gas at the substrate, such a iarge spacing is not without its drawbacks.
One significant drawback is that the incoming reactant gases disperse when travding such a large distance between their point of tlll 1;--.1 and the rotating substrate. Wlth such dispersion, an ~
volume of the react~Lnt gases bypass the substrate around the substrate edges and e~it the reacion chamber without reacting at the substrate surface. For e~unple, Fig. 1 shows various ~1, r.~ 5 of a downward and outward reactant gas flow within a CVD reaction space 7 which houses a substrate 8 which rotates on a rotaing susceptor 6. The ~llr~ t ll ~ 5 are from gas rings AM~ND~ 3H~

~ c e W0 9~i/33868 ~ rPcrius~4ll~6~4 5~
s ~
and a gas-dispersing ' ' (not shown) spa~d ~ 4 inches)or more above susceptor 6 and subst~ate 8. The ~ 5 illustrate what occurs when such a large spacing is used bet Yeen the gas-dispensing rings and sllu _ ' ' and the rotating substrate 8. As may be seen, the aYerage si~e of the boundary layer, indicated geneIaily by reference numeral 10, is fairly signifient and a substantial amûunt of the rea~nt O~ases 5 b,Ypass rotating substrate 8 and pass around the baffle 11 to be e~hausted out ûf the reaction space 7 by an ~ e~haust s,Ystem ~not shown). l~e significant bypassing of the gases S lowers the deposition rate because there is a reduced dcnsit,Y of reactants available at the substrate surface 12 fûr the surface rcaction. F ~ the wide boundary layer of reactant gases 5 at the substrate surface 11 affects the uniformity of the film deposited on substrate 8.
S~ rther, the wasted, unreacted gases which are ec!Lausted make the overall dcposition technique inefficient and costly.
Another drawback to the large spacing between the gas dispensing and dispersing structures and the rotating substrate is the inability to ignite a ~urr..;~.~ dense plasma pro~cimate the substrate. Specifically, in PECYD t~h";TI~ it is desirable to generate a reactant gas plasma close to the substra~e so that a sufficient densiq of actiYated plasma particles are present to proYide energy to the surace rea~on. P~L~.~1Y, a ~
plasma is necessary for lu.. ~ = PE(~ of titanium-containing films as disclosed in the U. S. patent rl~ rllrl~ entitled ~Method And Apparatus Far Producing Thin Flms By Low T~ c pl~sm~ E~l~i Chennical Vapor Deposition Using A Rotating Susceptor Rcactcr" which is being filed on AMEND~D 9~

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~5e san e day herewitl3~ However, igniring a su~tably deslse plasrna prc~cima5tethe rotztirlg substrate while ~ a stcady stzte gas flow to the plasma has s50t been ~ rA h~ achieved with curr~nt ~ utili~ng gas rings ~ lod~.~ ~S) and ~ ula ~ ru~L (4)10r .~ -- C~ 5~frcm the rctat~ng substra~
Therefore, it is an objectiYe of the presenst inverstion to disperse the reactant g~sses at substrate s~ such tslzt there is a small boundary lay ar5d sufficient densities of the gases at the subst5ate surface while ; ~ e a steady state gas flow to the substrate. Furthc, it i5 an objective to produce a de~se p5'asma at the substrate surface such that t~se plasma is ~-.C[,~.~
~1.. .1 I.~lA~i at the substrate surface to yield deposi~io~ of a PECYD film.
Sllmm~ry of the Invention In A- ~ with the above objectives, the invention provides 5 and methods for dispersing reactant gases close to a rotating subst5-ate in a CVD reaction c lambc such ts~ at t~ere is improved reactant gas f50w ov the surface of the substra5-e ar5d a reducs d boundary ~ay for more ef Eicient and uniform deposition and gas utsli~aion. Furth, the present inYentiOn produces a ' plasma at the rotating subs~te to produce PECVD f5l1ms ..~.~.1!~1~ for PEC~D of a titaùium containing film at low ~. . I 11~ . A~ 1. 1 . .
The preseFst inYention utilizes a ~as dispasing ' posiioned within on~ inch of a rotaing substra~e" The ~Iw.._.;.ui is spaced a suitzble distance below a gas-dispensing r5ng or oth dispensing apparatus such that a steady state flow of gas develops between the ring and the ~llu.._.5'1~ before being disbursed by the ~51U.._.5'~5 over the rotating AMEND~D 8HE5ET

r ~ ~ ~ q ~ o ~ ~ --W095133868 2~ 56 p.~sg4Ll36~4

2~
substrate. The ~.v ' ' is posi~ioned wil~u~. inch)of the substrate and preferably within 20mm tO produce a smail gas bounda~y layer at the substrate y~.
for more efficient and more uniform deposition of a C~D film.
In one ~ / a cylindrica~ structure or cylind e~tends be~we~n a gas-dispensing ring which is coupl2d to a reactant gas supply and the ' ' The r2actant gases are dispens2d into the cylinder at one end spacei away from the substrate and flow down the 12ngth of tbe cylind to be dispersed ov the ~otating substrate surface by the g~c-dispersing hol2s in the Th2 v210ciy profi~e of the flow of incoming reactant gases devdops within the length of the cylinder and the cyiinder confines the r~ant gases such that preferably the reacta~t gases ffow to the substrate surface only thrvugh the gas disp~ing ~I.u..~l.~i. The close spacirlg of the ~I~u. . i, as well as the steady state flow of the gases reduces the boundary layer over the substrate and ensures an efficient and uniform deposition of a C~D film on the subst~ate surface. The shape of the ' .._..,~i and the ~ o~
dimerlsion of the gas-dispersirlg holes, which are ~ 32 (0.03133 of an inc~jl, flatte~s the vdociy profile ûf the gases over the substrate to fur~her produce a uniform gas flow to the substrate. Close spacing of the ~I~u... ' and the reduced boundary layer yields more efficient CVD with less of the reactant gases bypassing substrate.
Ln ~' ' ""'-1' ~ with another featu~ of the present invention, the ~I,v... ' is biased with RF energy to c~e an RF electrode for use in PECVD. Plasma gases pass through the RF ~I.u. ' "dectrode and are e~cited prv~imate the ' ~..~lelec~ode to for.~ a 1~ plasma A~AEN~D 13biE~

o ~c or~ ~r ~ c~
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close to the substrate which suppiies energy to the surface reacion flur~ng PECVD (the ah~ .h~i l~ill be refe~red to as a ~ ~ifdxtrode .. . _~
throughout the -ApFii~Ttin~ where A~ ) The reduced spac;ng, i.e., less clS~
thAn)~l inc~, betwefn the ailU. fdfctrode and the substrate arld the improved gas flow of the presen~ invenion ensure a ~ piasma at the substrate surface which yidds sufficierlt energy for the deposiion of a film afcording to PECVD t~h~iT~r~ AdditionaUy, the ailu..~h ~ifdec~ode evenly dispers3 the reac~nt gas3 such that the f ' ` I plasma is uniform over the entire substrate surface. The cylinder and ai u ._.i.~Lfdectrode of the presen~ inYention prevent igrliion ûf a plasma above the ~I~u .~ ~dfdectrode and inside the cylindfr, or eYen in the dispa~.ung hol3 of the ' _.i.~fdxtrode. In that way, the plasma is generally ~ bdow the sl-u..~l.~fdectrode to enh~noe depositio~
and prevcnt ~ within the plasma.
In one c ~l o~ , of the pr3ent invenion, the cyiinder is made of nickd-plated aluminum and is coup~ed to a solid nick I
ailù~ ~ifdectrode by a f~uar2 insulz~ng ring. The insulaing li:lg dectricaUy isolates the cylinder from the R~ ailu '/dectrode to p:~rent ignition of p~asma in the cylinder. In another ~ ; the enire cylinder is made out of an ins~ tive f~uar~ matfcrial to prevent formation of a plasrna ~ b ~r~
within the cylinder. The allu. ' ' may be ~ inches)thic~
and generaily may have from 2C)C to 1,2C10 gas dispe~ng holes depending upon the diameter of the ailu .. ~;.~i and the substrat3 to be processed. The O ~'~9~
dispe~ing holes of the ~i-.,.._.i.~l~l_hu~ ar p~eferably(l/32 (0.0313) of AMEND~D 81 !EET

W0 95t33868 21 9 ~ ~ 56 - n ~ r ~ ;C eC~ r ~ o -an inch)to fi rth ensure that the plasma is confined below the ".u . " ~1, odc. A preferred ~ ~ o i~ for processing si~ inch . . . _~
dia~neter substrate wafers ernploys a circ~ r ,..~ with an 1~5~
Ll~ (G.5 inch)dia~neter arca havirig 300 to oOO gas d~ng holes.
As may be ~ of the cylinder, ~lu.._~i and holes may be adjusted depending upon, arnong other factors, the size of the chemi al vapor deposition charnber, the desired ~.u.._.i.~ distance from the substrase and the size of the substrate b~g p=sed.
The cylind and ~I.u 'lelectrode of the present invention is opcrable to de~iv ~ 200 to 30û watts of power at RF
r,~ as iow as 45û ~Iz and as high as 13.56 b~Ez Additionally, the present invention operates ~ with reactant gas flow rates between SO
and 50,000 sccm, as well as susceptor rotation rates between O and 2,0(~0 rpm.
The inYention and the par~icul~r advantages and features of thc p~sent invention w,~ now be described in furth det~i~ below with reference to th~ ~UIll~ g drawings.
Bnef 3e~.cri~tion of the Drawin~
The d~U~ JIII~, drawings, which are . ' in and constitute a part of this ~ illustrate ~ of the invention and, together with a general ~ " Of the invcntion given above, and the detailed description given below, serve to e~plau. Ihe principles of the invenion.
Fig. 1 is a ~ r.~ cross-secrional view of an e~ampie gas flow pmfile in a CVI~ reaction c~arnb with a mtating susceptor which does Ai~ENi~) 8H~T

~WO 95/33868 2 1 g 1 4 5 6 PCT/US94/13614 not utilize the present invention.
Fig. 2 is a cross-sectional view, of an ~ L ' of the present invention.
Fig. 3 is a ~' _ cross-sectional view of an e~ample gas flow profile in a CVD reaction chamber using the present invention.
Fig. 4 ls a detailed view of tne L ' of the present invention illustrated in Fig. 2.
Fig. 5 is a top view of a gas-dispersing ~I.u.._.i.~ used with the l~u ~ of the present invention shown in Figs. 2 and 4.
Fig. 6 is a cross-sectional view, of another ~ of ~e present invention.
Fig. 7 is a top view of a gas-dispersing ' .. ' used with the ~ of the present invention shown in Fig. 6.
Fig. 8 is a graphical illustration of the deposition rate versus rotation rate for a CVD reaction with and without the present invention.
D~ ~il~i DescriDtion of the Invention By virtue of the foregoing and in ~ with the pr_ciples of the present invention, Fig. 2 illustrates one ' of tne present invention. A CVD reactor 20 includes a deposition cha~nber housing 22 which defines a reaction or deposition space 24 therein. A rotating susceptor 26 supports a substrate or wafer 28 within reaction space 24. A reactor suitable for the purposes of the present invention is a Rotating Disk Reactor available from Materials Research Cn~rn~tinn (MRC) of Phoeni~, Arizona The reaction or deposition space 24 within housing 22 may be selectivdy e c ~ , c O ~ ~ c WO 95133868 ~ 4 S 6 C ~ ~ ~CI'IUS95~rl,36l ~, f o 1300 ev~uated to Yarious different internal pressurcs, for e~am~le, fron~.5 to 100 Tor~. The susceptor 26 is coupled to a Yar;able speed motor (nat shown) by . ~.
shaft 30 such tt~t the susceptor 26 and substrate 28 may be stationary or may be rotated at Yarious speeds such as between 0 and 2,000 rpm. When rotating, susceptor 26 crcates a downward pumpirlg action in a direction generally ~, ~ li "1~, the substrate surf~Lce 29. Susceptor 26 is also heated by a suitf-.ble heating " ~ (not shown) coup~ed to the susceptor 26 so that susceptor 26 may heat substrate 28, such as betwe~n 200 and 800C.
E~tending duwllw~ from the coYer 32 of housing 22 is a cylinder assem~ly 34 which supports a gas-dispersing :~IU.._.L~I 36 aboYe otating susceptor 2Ç and substrate 28. The cylinder assembly 34 preferably ~ 2~
psitions ~.u.._...~ 36 wit~i3,(1 ir~ch)of substrate 28 and more preferably witbin 20 mm of substrate 28. The cylinder assembly 34, in ~ with a generally circular opening 42 formed in the coYer 32, for~ns a vertical flow passage which e~tends ~n the direction of reerence arrows 43 between a gas distributor cover 46 and ah~ ~i 36. Gpening 42 of cover 32 forms a cylinder conce~tric with cylinder assembly 34 to def~e a generally cylindrical flow passage 44. As discussed further ~...~.~cl~ ,1-~ 36 may be coupled to an RF power source 38 such as by an ~ ` RF feedline assembly 40 which e~tends through a~ opening 48 in the gas distributor coYer 46. R~: feedline assembly 40 is used to bias shGwerhcad 36 so that it acts as an e~ectrode for PECVD techniques as e~plained in greater detail below. A
sealing structure 49 seals the opetling 48 around feedline assembly 40. Plasma and reactant gases are introduced i~to vertic 1 flow passage 45 by concentric , ,~ C r ~ c '` ' ,,, ~ , t 95/33868 -- ' ' ^ - ' ' ~ ' ' ' ' ' grs rings or halos 50, 52. A5 wiil be ~ r~i other gas dispensing ~trlT~iln~ l~}lt ~e utilized as are known by a person of ordinary sl~ll in the ar~ The concentric rings 50, 52 are cûup~ed to A~ Vl~l; `' ga5 sUppl~:5 (not shown) through lines 56, 58, ~h~., y and the rings include a number of gas dispensing hoies 54 which evenly dispense the gases around the perimeter of f~ow passage 44. Showerhead 36 includes gas dispasing holes 64 for dispe~ng reactant gæs over subst~ate 28.
Cylinder assembly 34 inc~udes a cylinder 60 and an ~nsula~r r~ng 62 which elecrric~ily separat~s cylinder 60 and ~-u.._~..~i 36 whene~r ~ ,..~I.~i 36 is biased with RF energy. CyEnder 60 is prefe~ably e~ec~rically gTounded by ground line 61. The insula~or ring 62 is preferably ~r, " , ~i, ~ in diameter and width as indicated by reference ~ ' 631 to ensure complete elec~l separation between cylinder 60 and ~Lu ' ' 36 along the ennre at~'nment intface between the cyEnder 60 and ~I.u.. l.~l 36 (see hg. 4). The insulator ring may ~e made of quartz mate~ial such as Quartz T0~-E available from Gener I Electric and in one ~ the ring ~q~
has a thichless of ~ v~ t~ (0.75 inchi~s~i, In use, C~rD reactant gases are introduced at the top of flow passage 44 through rings 50, 52, and the gases are dlawn generally ~u ,~w~dl~ in the direction of arwws 43 by the downward pumping action of ...
rotating susceptor 26. The ~;.,,.._~I.c~ 36 is preferably spaced from 2 to 4 inches f~m the rings 50, 52 ti~ ensure a steady state flow of the gases at _~I.~i 36. More ~lly, as the reactant gases flow ~' . ..w~udl.~
through flow p~ e 44, a velocity profile develops. The vdocity profiie is a ~ME~;DED ~i~iE~T

~ ~ ~ o c ~ ~ r c WO 9~i/33868 ~ 3 ~Ig~4~6 PCT/US9,/1, 1,. ...
of gas vdociies at various points in the gas aOw as measured acmss the gas ffow ~ ~ to the flow direcion 43. Generally, the vdocities acmss the gas flow at the top of the flow passage 44 near nngs 50, ~2 ate generally e~ual. However, at the bottom of flow passage 44, gener liy above the top surface 37 of ~llu.. ' 36, the vdocity pmfile of the g~as flow, indicated by armws 45, has reached a steady state. At steady state the vdociy of the re~ant gas flow is ger~ally greater in the center 67 of the ... ' ' 36 tha;l it is at the periphety 69 of ~ ll~d 36. Showerhead 36 flattens out the vdociy pmf~e of the reactant gas flow acmss the bottom surface 39 of the ~.~.. ' ' such that bdow ~.u ~il~ 36 pm~imate substrau 28 the flow vdocity near the center 67 of llu.._fll~i 36 is ger~eraily e~ual to the flow velociy at the periphery 69 of the ~.u.._.ll~d 36.
The spacing betwe~n the rings 50, 52 and ~' ... ' ' 36 ptovided by cylinder assembly 34 and flow passage 44, an'~ne inc~ or less s)acing between ~llu.. .;.~i 36 and rotating substrate 28 achieved by the present invention yields uniform gas flow over the top surface 29 of substrau 28 with a very thin boundary layer. As shown in F~g. 3, utiliz~ng'~(l inch) or less -' .. ~1l~1 spacing of the present invention the c~ of reactant gas flow 80 are hdd much closer to the substrate 28. The boundary layer height as indicated by referenc numeral 81 is effectively reduced, and thus, there is a greater density of reactant gases pres~L at the subst~ate sur~ 29 to take place in the chernical vapor deposition of a fiIm. This ensures that a greater percentage of reactant gases are ut l~ed it~ the CVD reaction, and therefore, a smaller percentage of the reactant gases bypass the substrate 28 AA~E~ D 8HEET

~ ~ e ~ C ~ r ~ ~ c ~ . t ~ e ~YO 9~133868 , P,CIl tS94i1361$ r -14 _ 5 6 unreact d to be e~hausted by vacuum opening 71 amund baffle 73 and out of the reaction epace 24.
., _~
As discussed above, the reactant gas flow through f~ow passage 44 is drawn du...~w~dly and thmugh ~I-u..~ i 36 by the do~vnward pumping action of the mtating susc~plor 26. An incr~ed susceptor mtation rate pmduces an increased deposii on rate because an increased quantity of reactants are being pumped to the surface. This is termed the mtating disk effect The pmcess curves in Fig. 8 irlustrate that the rotating dislc effect occurs for the reduced ~;lu .. ~I.~-to-susce~tor spacing achieYed by the prescnt invention. That is, as the mtation rate of the susceptor 26 inc~ases, the deposition rate inc~s indicating that a greater quantity of reactants is being pumped to the surface 29 of subst~ate 28. A ma~imum der~osition rate is reached whenever the incoming and downward gas flow to the substrate is equ 1 to the outward flow of gas away from the substrate. Such a conditi is generally refd to as matched gas flow rn the present invention, it is preferable to utili7e matched gas flow. Further discussion of matched gas flow is disclosed in the pending ~ r~tinn entit~ed, ~A Method For Chemic I
Vapor Deposition Of Titanium-~ltride Fi}ms At r ow T ~ . Serial (~9~i ~ u~i s~ S,~ t~o ~3~sc~), No. 081131,900, filed October 5, 1993,1which ~r~Fi;r1hnn is he~in by reference.
At susceptor rotation raus which pump the gas ~.~W~Y~dl~ at a rau higher than the rate at which it can be carried away from the subst~ate, i.e., unmatched flow, the deposition rau drops because ~ ~ t~ and bacl~flow of the gas develop at the substrate sur re. ~ Fig. 8, the depcsition '4At~iXD ~

^,- C ~ F ~C C ~ ~ n O
WO 95133868 ~ ; pt ~r/uSs4~ 4 ~

rate curve for one ~h~i;~l 11 of the present invention, indicated by reference numeral ~2T shows 1~ u-t rates than thc curve achievcd without the present invention which is indicatcd by refe~nce numeral 84. Curve 82 indicates that less of the reacs~nt gases are bypassing the wafer surface 29 in the pr~sent invenion, and ~ ly~ more are IIAI 1;~ ;lIAI;ll~ in the surface CVD reaction. F~ curve 82 is fla~er than cilrve 84 which indicates an improved proi ess sta_ility over a wider range of rotation rates when usir~g thc present invention In ~, IllliA~/ ~ with another fea~ure of the preserlt invenrion, the ~..u..~..c~i 36 may be biased with RF energy to f mcion as an R~ electil~de for PEC~ID t~ rhni~ t C When plasr~a gases, such as H2, N2 and N~3, arc intn~il-rrri, such as through rings 50, 52 ihey are e~cite~3 into a p3zcma by ~u..~ ~ielectrode 36 prefera~ly below the ~lu~ ~/electrode 36 and rlot within cy3inder 60. The ~l'l""''"~ inch)or less spaci~g between the PF
~I.u~ .~d/electrotie 36 and substra~ 28 creates a very ~- IIAII 'i p3asma near substrate 28 which is useful for low ~ c PECVD, and ~. l u~ul~ly for low t~ I PECVD of titarlium~ontairling films. Specific usesi of t~e p~sent invt ntion are i3Iustrated in a co-pending applicaion c~tit3ed ~ot~3 arld Appa~ s for Producing ThiD Fi3ms by 3 ow T ~ A 1111 t~ P3~sma-Enharlced Chernical Vapor nt r~itir,n Usirlg a Rotating Si.-isceptor R~actor~, filed on the same day herewith ~which is completely inw~u~ i he~in by ~ 1i; wlv~ c~ c~c~ hr~q3/~6~ t~cms~d.~
referenct~ Several e~a~nples of use of the ,,1,l.~1,.". .,1~ of the pres~nt invention are given be30w. The terms ~;lU~ Wi 36~ and ~I.u. '/e3ectrode 36~ will be used ~ U~ -I t~is ~MEIYDED 8i?~T
. .

,, 9 .. ~ . r~ ffr ~ r WO 95133868 2~ 5 ~ ~ j f .

application to designate a sirnilar stnicture for non-RF electrode and RF
elecirode fos of the present invention, ~h~y.
More specifically, RF power source 38, through RF feed~ine asse.~nbly 40, biases ~I.u .. _...~ilelectrode 36. The dect icahy grounded susceptor 26 forms a~other par 'llel electrode. An RF field is created prefeiably between s;.u. ' ' 36 and susceptor 26 and the RF fidd e~cites the plasma gases which are dispersed through holes 64 so that a plasma is generated genei2~1y beiow ~I.u..~..~llelectrode 36. It is preferable that the plasina is crf ated below the ~;-u.._...~/electinde 36 and not within the f~ow space 44 above the ~u ' '/e~ectrcfde 36. It is furiher pieferable ti~at the plasma is not created within dispersion holes 64 but rather is confined below the bot~om surface 39 of ,I.u . ' '/electrof~e 36. Thus, the dispersion ho~es 64 are ~ ~ so that the gener ted plasma is preferably confined bdow sui~ce 39 of ~l~u 'lelec~od~ 36. In one ~ f~~ l of the present ~ Q ~qft~n~
inveniIon, the diameter of the dispersng holes 64 i~(l/32 of an inc~
r, ~ other features of the present invention ensure that the generated plasma is ,, ~ bdow the ~lu. . ' ~f~hu~c 36. For e~ample, insulator sleeYes 96, 98 ~re uti'.-7ed within the RF feedhne assembly 40 to insulate the RF line fiom the meta'~ of cylinder 34 and housing 22 as i7~lustrated in Fig. 4 ;ind discussed in greater detail bdow. Additionally, quartz insu~ator ring 62 e'lectiically separates tite ~I.u.._.i.~/decirode 36 from cylinder 34 tofur~ier confine the plasma below ~i~u .~l~iielectiode 36. The rotation of susceptor 26 and a. u...~ h.~ pumping action and the flow of gases within cylinder assembly 34 and flow passage 44 enstues a uniform flow of gases to ~ME1`1~D ~3HEET

wo ssl33s6s 2 ~ 9 1 4 ~ ~ ~ ` Pcrtuss~tl3~
the plasma for uniformiy sustauled plas na and unifor~n rlq~ncninn Wlth PECVD according to the principles of thc present invenion, a reactant gas, such as FiC~, i5 also int~~ into flow passage 44 such as tnrough a gas ring similar to rings 50 and 52, although the plasma gases and the reactanl gases are preferabiy in~--~ through different rings.
l~e gas particles of the reactant gases are also e~cited by the RF fidd generated by sl,u..~..~i/de~de 36 and susceptor 26 but do not form what would be defined as a plasma. Therefore, a mL~tl~re of e~cited reactarlt gas paric~es and a plasma of the plasma gas paricles are r..." ~,...,/t~ ; above 2s~
subsr~ate 28 and preferably witC~,~(l inch)of the substrate in ~ with the principles of the present inveniOQ
The ~F ~I.u.._~..~i/dectrode 36 may be e~cited with RF
energy having a f~uency in the range of, for e~ample, 450 ~Iz to 1356 ME~, and the inYenion does not sen to be !~Li~ly fre~uency sensiive.
The gener~ on of a unitorm plasma withC~(l incl~ or less of substrate 28 yidds a high density of useful p~asma gas radicals and ions pro~imate the substrate surface 29. The pumping action of the susceptor draws the plasma particles and e~cited r~actant gas partic~es to the substrate to react and form a fi~m.
Gen~rally, a substrate rotation rate ~u--.~...c between 0 and 2,û00 Ipm might be utilized with the RF ~.u..- ..~lldectrodc of the present inve~tion.
However, no rotation, i.e., 0 rpm, although not drasticaUy affecing the deposit~on rate, seetns to lower the ~.;ru~ of the reactart and plasma gas flow and the subseo,ue~t ~i~n~itinn A usefui rotaion rate for depositing itanium~ontaining films has been found to be around 100 rpm.

AMENDED ~HEET

.t < ~
WO 95/33868 ~ ~ ~ PC TN594/l~if4 ~

Since the s;.~. ' '/e~ectrode 36 of the present invention generates apiasma conta~ning radicals and ions of the plasma gases, the .~i spacing and deposition ~J~IAIII- `` ~ should prefelably be chosen to achieve a useful mi~tu~e of rA~Ticals and ions at the subst ate surface 29.
While some ion b~ of the substrate 28 is beneficial because it supp~ies additional energy to the grol,ving film lay on the surface 29, too much ion ~ of a subst~ate may damage the integrated circuit dcvices on a substrate. r 1 , "~ a high density of ions leads to poor fiE n . ",r IllAi,ly as ions have a tendency to stick to contact and via surfaces. As discussed above, ~1..,..- ..~lel~_uuic to-susceptor spacing wi~(l inch)and preferably within 20 mm has proven usefi~l.
Fig. 4 discloses an RF sl~u. ~ ~/electrode ~II.II~r,lllA~l~l,, simi~ar to the c. .I.i';~ \ in the ,1 ,I,o~ of Fig. 2 e~cept in greater detail. ~erever possible similar eference nume~ls will be utilized between Figs. 2 and 4. There i5 sho~vn in section a portion of C~D deposition charnber housing 22, to which is mounted the RF ~IIu..~~ /electrode assembly 34. The h~ ' 'lelectrode 36 includ an RF line ste~n 68 mounted thereto which is one of seve~al ~ ma}ting up the RF
feedline assembly 40 supplying RF er~ergy to a..u.._.l.~lle~xtrode 36. The RF feedline assembly 40 also acts as a heat pipe to conduct heat away from ,..u ._.l.~/dxtrode 36 as is discussed in greater detail ~.~ci..l..lu....~e stem 68 may be machined ~. \ . ", Ally into and integr i with the upper surface 37 of ~;.u . ~..~i/elxtrode 36 to increase the RF signal ~ nn~ inn and heat rnn~ nn effiaency see Fg. 5). The RF feedline asse~nbly 40 AMEND~L~ 9HEEl 2~gI~6 includes an i~F line 92 which comprises line stem 68 and an additional length of tubing 94 welded thereto such as at 93 to achieve the desired overall length of the i~F iine 92 and to attach tubing 94 to the stem 68. The ~hu..~.~/electrode 36 and the integral line stem 68 may be made of Nicl~
200, while RF line tubing 94 may be made of a highly conductive material such as 6061-T6 aluminum. However, it will be ~, ' by j~ersons sl~lled in the art that other materials can be used for the i~F line tubing 94, such as Nicicel-200. in one c ~ the RF line tubing 94 is made of aluminum coated with an outer ~ayer of nickel to prevent an RF p]asma from fornung within said cyiinder 60 of the cylinder assembly 34 during use of the RF s;.u.._.~.~/electrode 36 according to the principles of the present invention.
As already discussed, sl.u... ' '/electrode 36 is perforated with a pattern of gas dispersion holes 64 to distribute the reactant and piasma gases eveniy during CVD processing. As shown in Figs. 4 and 5, upstanding RF line stem 68 is provided with a , r~ shoulder flange 70 adjacent and e~tending generally parallei to ' ... ' '/dectrode 36. The flange 70 is spaced above ~,Iu.. Ih~i/electrode upper surface 37 and permits the gas dispersiûn hole pattern to e~tend beneath the shoulder flange 70, thereby gas flow ':~ 1 ^ r li l r, the flange 70 aids in the conduction of the RF energy along iine 92 to ' .._.I.~/electrode 36, assists in cooiing ~I.u... ' '/electrode 36, and provides ' ' support for ceramic isolator tubes 96, 98.
The RF ~I.u... ' '/dectrode assembly 34 of Fig. 4 fur~her WO 95/33868 2 ~ 9 ~ ~ ~ 6 PCT/US94113614 ~
~20 -includes first and second ceramic isolator tubes 96, 98. ~ u.~ly, which are concentric with and surround at least a portion of RF line 9~. As shown, ceramic isolator tubes 96, 98 are supported by ~ r.~ l shoulder flange 70. Tubes 96, 98 may be formed of the ceramic alumina (99.7% Al703), which is readily ~, ."...,., . :-lly available, such as from Coors Ceramics of Golden, Colorado. Isolator tubes 96, 98 prevent RF plasma from forming around the RF line 92 during CVD processing by isolating the metal RF litle 92 from any of the plasma and reactaM gases present within the cylinder 60.
It is desirable to p}even~ the formation of a plasma within the cylinder 60 in order to concentrate the plasma below ~IIu..~ electrode 36.
Additionally, and as described more fully below, the isolator tubes 96, 98 operate to reduce and prevent electrical shorting between gas distributor cover 100 (which is at ground potential) and RF line 92 al the opening 48 where RF
line 92 passes tbrough gas distributor cover 100.
Gas distributor cover 100 is mounted to housing 22 by means of a plurality of screws 102. As shown in Fig. 4, gas injection rings or halos such as rings 50. ~2 (shown in phantom in Fig. 4) are located slightly belûw gas distributor cover 100 to supply the CVD reactant and plasma gases to the inside of cylmder 60 as already discussed. Gas injection rings 50. 52 may be only two of a plurality of concentric rings for i~ udu~,hl~ numerous reactarlt gases into the cylinder 60. A seal assembly 49 prevents vacuum leaks at the ûpening 48 where RF line 92 passes through gas distributor cover 100. This assembly includes a shaft seal and a flange seal. As shown in E~ig. 4, a ceramic seal plate 104 is pressed Ju . ~ lly by two stainless steel clamps ~WO 9~/33868 21 ~ 1 ~ 5 6 PCTIUS94/13614 106. Cl~unps 106 are biased against distributor cover 100 by spring w~h~/~.cw assemblies 108 to obtain a ~ ~ downward force on the Seal t to insure proper sealing, to 7 ' tolerance stacks ~n the seal ~ and to take up l I changes due to thermal e~ pansion which may occur during CVD rm~ .-ccin~ Seal plate 104 presses du....w~ul.~ on a stainless steel ferrule 110 which in turn presses down on an ~ring 112 seated in ceramic seal body 114. The downward force e~erted by cl~unps 106 on seal plate 104 also forces seal body 114 du....w,udl.~ against gas distributor cover 100, which ~ the ~ring 116 located between Seal body 114 and gas distributor cover 100. It should be noted that seal body 114 has a du...~wa~dl~ e~tending annular flange 118 which surrounds RF line 92 over the entire length of it which passes through gas distributor cover 100.
The lower end 120 of annular f~ange 118 e~ctends ' ..~w~dly to a point where h meets the inner ceramic isolator tube 96. As shown, the outer cer,unic isolator tube 98 e~tends further upward than isolator tube 96, such that there is no direct line betwen gas distributor cover 100 and RF line 92. This prevents arcing when the RF line 92 is used to supply RF energy to ~ ..~I~/electrode 36.
Biasing of the ~hu... ~/electrode 36 with RF energy in addition to the i . utilized in CVD techniques heats the ~;~u.._.;.~d/electrode 36 during use. To erlsure proper operation, 51~u.._lh~d/~ ud~ 36 is cooled, and to this end, the RF line 92 also functions as a heat pipe structure. With respect to heat pipe structures, such devices are known, per se, and in the present invention, the heat pipe structure ~VO 95/33868 PCT/~S94/13614 21gI4~

is used to carry off heat from thc ~ . "dL~h~l- 36 generated by radiant energy from the heated susceptor 26, as well as by the RF energy applied to the ~ l~h~c 36. The center space 122 of RF line 92 is provided with a fdt or other suit~ble capillary wicking material liner (not shown). Space læ is sealed with a liquid (e.g., acetone) therein under its own vapor pressure that ent~rs the pores of the capill2ry material wett~ng all internal surfaces of RF line 92. By applying heat at any point along the lengt~
of the RF line, the liquid at that point boils and enters a vapor state. When that happens, the liquid in the wicking material picks up the latent heat of ~ LiOI~ and the vapor, which then is at a higher pressure, moves inside thc sealed pipe to a cooler location where it condenses and re-enters the liner.
Thus, the vapor gives up its latent beat Of ~c~ and moves heat from the "input" to the "out,out~ end of the heat pipe structure. As a general frame of reference, heat may be moved along a heat pipe at a rate of / 500 mph.
~Ith reference to the specific C'"'r;~ 'll utilized in Fig. 4, the "input" end of the heat pipe structure is the end of RF line 92 which is affi~red to ' . I/edectrode 36. The "output" end is the upper end of RF
lisle 92 shown in the Fig. 4 which has a liquid-cooling jac~et 124 sealed around it. The seal is effected by O-ring shaft seals 125 and 126. Cooling jæket 124 is preferably a polymeric material and is provided with TEFLON
fittings 128 and 129 which connect TEFLON tubing 130 to cooling jacket 124. A suitable cooling liquid, such as water, flows through tubing 130 and cooling jaclcet 124 to carry heat away from RF line 92. This wo ssf33868 1 !~ S 6 r P~T;USs~/136 4 , ~ ,, p?3~uts direct contact of the cooling liqu~d with the RF line 92 for cfficient cor~duction of heat from t,he iine 92. Additionally, with thi5 ~r -'~ at . . ~ , no time is the CYD reactor chamber e~posed to the pûssibility of an internal cwlant leak, nor is there any corrosive effect on me I tubing by RF ca~ing liqlud. ~5 stated, the fluid which pas~c through l ~ ~LON tubing 130 and caT~ies the heat away from the RF line 92 may be water, although a variety of fluids can be used depending on the heat to be conducted away from the line 92. RF li~lc 92 also includes a cap 132 which is welded in place and has a fill tube 134 for filling the inte~nai space 122 with the de ired f~uid. A suitable T~ available heat pipe may be obtained from T; P~nn~ n~ Inc., of Lancaster, PA.
As discussed, cy}inder 60 forms part of cylinder assembly 34 a~d mounts ~1.. . ' '/ele~de 36 to the housing col~er 32. The cylinder 60 is n.l.,...~'.,... ~l such that the ~.u.._...~ldectrode 36 is posiTioned ge~erally c ~5~
with~l inch)of suscPptor 26 after taking into account the thickness of ring 62.
Showerheadfdectrode 36 is fastened to cylinder 60 by means of screws 136, which are preferably made of a materi~l that does not corrode in the p~ce of an RF plasma. One such material is ~asteiloy c-æ, which is a trade name of ~anes T"t. .~ l, of Kokomo, IN. Suitable sc~ws made of this material a~e a~ailable from Pinnacle Mfg. of Tempe, AZ.
Insulator ring 62 e}ectrically isol;~s ~I.u. ' 'fedectrode 36 from cyLinder 60. The insulator r~ng may be formed of quartz and preferably of a suitable quality quartz which has few andfor ~ery small inte~nal ble nishes su~h as air bubbies. A suita~le qT~tz mate~ial is ~2uaT~z T08-E a~ailable from AMEi~ D 3HEE~

~ r I r ç o ~ ~ ~ c o o WO 95/33868 21 91 1~56 ~ ~ cI/lJs94rl36~4 creaus Amersil of Tempe, Arizona. The quartz m. ay be machined to form a 19~
quarez ring ~ ; ~314 (0.~5) inches)tl'~ck and having diameter . ~
~lim~ncinnc w'~ich mr~ch t"e rl ~ of the cylinder 60 arld .u _ ' '/dec~ode 36 between wnich tl'le insulator ring 62 is fL~ed. Scrcws 136, which are at ground potentia, are isoLated from the ~' .._~L~/ul~uu~c 36 by two ---~ ; ceIamic isola~or sLeeYes 138 and 139. Quartz ring 62, w~hile insuLatu g :~;IU.. ' '/dectrode 36 fiom cylinder 60, is a'so ~used because ûf the significant resistance of quartz to thermai shoclc. This is imporeant bec~use the RF ~u. ' ~'d~u~ 36 below ring 62 becomes hea~ed to a higher ~ and more rapidly, than cylinder 60 above quartz ri..~g 62, thus inducing them~al shock and strecs in ring 62. Screws 140, which may be made of the same matiaL as screws 136, ~re uti7i~ed to affi~ cy7inder 60 to housing 22.
RF e~ergy is conducted to ~I.u . ' ~lelectrode 36 by RF
feedline, ssembly 40 ~ stem 68 and tube 94. Isolator tubes 96, 98 are needed to dectrically iso~e arld prevert arcir~g between tube 94 and a~y parts of the me 1 housing 22, including distributor cover 100. r 1~ .. -the appa~us includes a seal aro~md tubir~g 94 at the location where it passes through distributor cover 100.
RF energy is supp7ied through a shidded RF supplying cable 142 which is connected to an RF power source 38 (shown in Fig. 2) and has a u~ connector 144 at one end. Conneceor 144 mates with anothc U~F
conrlector 146, whicel in turn is coupled via a le..~gth of 12 gauge wire 148 to a stainless sted shaft collar 150 mounted at the upp~r end of RF line 92. The ~MEN~D ~

~ ~ c c ~ c o c WO 95133868 9~ ~CrlffS9 ~113S}S ~ ~ r --2 5~
shaft collar 150 is in fricnonai contact with RF line 92. To that end, collar 150 may include oppvsing clam-shell clamps which may be tightened ~gainst one anoth by means not shown to finnly grip line 92. With this A~ IA.I~.~ .. ;
there is m~nimal resistance to the flow of RF cu~rent through line 92. Thc segment of RF line 92 which is e~posed above shaft collar 150 is isoi~ted frvm the grounded metal shielding 152 by a polym cap 154. The apparatus ~s capable vf dehverLng 250-300 watts of RF r~ from 450 KHz to 13.56 M~z. .
Fig. 5 disclos~s a top view, of one ~I,v~ i.~l design for the ,.I.o.l;,., ~ of the present invention shown in Figs. 2 and 4. Showcrhead 36 is genesally circular and inc~udes dispersion holes 64 ~ O~A~
generAily throughollt its entu~ a~ea. Showeshead 36 may be A .~ ~8.0 inches)in total diamet~r with an area 156 contaiDLng holes o4 havin a I ~o~._ g diameter'~6.5 inche~ As will be A~ ` i by a person of ordinary sl~ll in thc art, the diameter of the :u.u.._~.,~d 36 and the hole area 156 will depe~d upon the size of the substrate wafers which are processed using the current invention. Showerhead 36 may have genesAiTy fmm 2C0 to 1,200 dispersion ~oo~
hûles 64 and prefesably for at~(8.0 inch)~ ;.~i has fmm 300 to 60'vl ho3es for dispersirlg the gases. As discussed above, the inner diameter of the holes O .~9~
64 is ~cf~ Z(1/32 (0.0313) inches~ to prevent a plassna fL~vm formirlg within the cyiind 60.
~ i 36 includes a pesipher ~ edge section 157 with spaced openings 158 spaced around the pesiphery of ~I.u~ 36 which receiYe screws 136 or other fasteners for connecth~g ~I,u..~L~i 36 to hhe C rr r; r o ~ ~ oo ~ ~
WO 95/33868 ~I gt ~ S 6 quartz ring ~ shown in Fig. 4. As already shown, the ~llu.._~l~l 36 includes a stem 68 whichl forms flange 70. Stem 68 and flange 70 are hrmed integr lly with ~hu.._.h~ 36 and form part of the RF line assembly 40 connected to -' ._.h~ 36. The ~IIu ~I.~d, 36, including sum 6~, is formed of an dectrically conductive material and preferably is formed of Nlcl~ 200. The ~.u ' ' 36 in one r."l.~ .. ; ûf the inYention has a t,'~iclm~ss dimension in the holed area 156 of prefera~(1/4 (0.25) ~che~.
Thc I ~i ~ of the present invention as illust~ated in Figs.
2 and 4 have been udlized to deposit layers of titanium ~nd titSuiium nitride atlow substrate ~ Various e camples of CVD and PECVD metuods and use of the present inve~don are illustrated bdow. Deposidon parameurs are given for each e~ample and tne results of the deposidon are illustrated in tables associated wit,'. parlicular ~ Table I illustrates use of the of the present invendon to deposit a dtanium rlitride (I~N) layer on a substrau utihzing both nigen gas (N~) and hydrogen gas (H2) and dtanium De~osition Parameters for Table No. I
r,c~ (sccm) 10 II2 (sccm) 50C
N2 (sccm) 500 RF Power (watts) 250 ~ 450 KEIz Reaction Chamoe~ PressurelCrorr) 1 I Ll~) 133 ( 1 T~) Susceptor Rotadon Rate (rpm) 10û
Substrate Temp. (C) 400 Deposidon Time (sec~nds) 180 .
AMENDED ~H~T

r. ~ c ~ r c r r ~ c A
W0 95133868 21 9 I ~ 5 6 - -TARt F: NO. I
WAF3~ NO.
~t 1 2 3 4 5 6 7 8 9 ~0 P~ me?~
r~ lALyer ~5 1023 1221 L62 122~ 1224 1141 1348 1400 1~06 ~C~ (A) ;kpOricio?l 2?5 341 407 421 409 408 380 449 481 389 R,ae ~/~i11) ~t1530 2686 41~8 3108 855 4478 3982 4658 3449 ~501 ~si~viq 4 ~uO -cm) Sllsce~or 470 480 488 47~ 470 460 460 460 460 460 Temp Wafers 1 and 2 of Tabl2 1 were silicbn, while t~e remat ung wafers 3-1~

were therma~ o~de. Wafers ~10 rece~ved a 250 Watt RF plasma ann2al for 120 s~s ,_~ JI Ph ~5 at an NH, ~as rale of S000 sccm, at an ~ntGai pressure o~ Torr~ ~waf2r 6 was de a~i Tarr),), and the susceptor rotation rate of 100 rpm. Therefore, as may b2 seen, a layer of .
titarium rutr de may be deposir~d at a suostra~e ~ t~' 'y 400'C, which is subst~tia'lY less than the t~ re~uired hr tr~i io~.2al the~mal CVD processes.
The e~ample of Table 2 be~ow was ~ ~l~i~ ~i wit~. the pa.;2meters of Table l~cept at a subst~ate ~ of 600'C, ant a layer of TIN was deposited ac~ordirlg t~ Table 2 using the deposiion ~AIAIll rl ~ below.
De~osttion Pa~meters f~r TAhle No. I

r,c~ (scc.n) 10 E~2 (s~cm) 500 N2 (sccm) 500 RFPow (watts) 250 ~ 450 ~z Reaction Chamb Pressurei(Torr) 1~ ) 133 (I ri,r,) Susceptor Rotation Rate (rpm) I00 Substrate Tp. (C~) 600 Depositio~ Time (se onds) 180 SU~STiTUTE Sl IEET (RULE 2b) AMENDED ~3HEET

r ~ ' C
WO 95/33868 2~ S 6 - ~ ~ pCTlUS9411361~

TARLF NO. 2 . .~ W~F~ NO.
Results atld 1 2 3 4 5 6 1 8 Addition Patam~
TiN Iayer 6n 822 740 768 767 765 m 9lO
thickness (A) Deposit~cn tl9 274 247 263 256 255 258 303 Rate (Almin) I~lyer 391 254 432 50 471 949 g73 27~0 Resisti~ity (an -cm) Sus~eptor 650 650 650 650 650 650 650 650 Temp (~C) Wafers 1 and 2 of Tab~e 2 were s~licon and wafers 3-8 were th e mal o~ide. An RF plasma, ammonia anneal was perfor~ned on substrate wafers 6-8 of Table 2 at a pow lever of 250 War~s for 120 s~onds, and an a~nmonia ~ , rate of r ~
5000 sccm. a pressure~5 Torr)and a lO0 rpm rotation rate.
The ~ of the present inventior~ as illustrated in Figs. 2 ar~d 4 have also been uti~zed to deposit a layer of pure titarlium. Table ~ below s~ts forth the results and parameters of a deposition run which resu}ted in a deposited f~m of ly 84 % titanium on a thermal o~ide wafer at 650 C. This was an e ccell result for such low ~ chemical vapor .~ iri~

. ~.
SUESTITUTE SHEET ~RULE 2q~MEl~loeD ~I~EEl' f~ c ~ ~ ~ o .7 ~ o wo 95~3868 1 ~ $ 6 r r ; I'~TIC'594/~ ~614 , ~, -2g-D~ ~osition Parametf rs for Tablç I~To. 3 TiCl~ (scem) lO
X2 (sccm)~ 500 RFPower (watrs) 250 ~ 45û KEz React~onChambe~rçssurel(~ lt (~),133 (~ T~) Susceptor Rotat~on Ra~e (rpm) l~0 Deposiion time ~sec) 2700 Subsr~a~e T~ (C) 50'5 TABLE NO. 3 WAFEB NO.
Rf su~ts and Additional Parameters rl lay 19~3 ~h~clmess (A) Dep~sir on 44 Rate (Almin) Layer ~2g Resistivity ~n -cm) Susceptor Temp ( C) The subst~ate wafer of Tabie 3 was not anncaled with a~ ammonia plasma as discossed above.

In Table 4, the flow of X2 was inc~eased to 5000 scf m for wafers 1~ and ~ P~
to 37N sccfn for wafers 5-9. The deposirion ptessure was inf~sed t~(5 Tot~ For wa~ers 5-~, a flow of 0.5 standard liters per ~inute (slm) of Argon was utilized with the A2 as a diluent. In Table 4, wafers 1-2 and 5-6 were sil~con, whi e wafers 3-4 and 7-9 were t'nermal o~ide.
.
-SUBSTITUTE SH'--ET ~RULE 26) ~MEND~D 9t~fET

C C ~ 1 ~ C r O r C <I
WO95/33868 2~gI~S6 ' ~ ~ P~NS94/r136~4~ ,.. ' ,,' ', Parameters for T-Ahl~ 4 , . ~ ,rlC14 ~sccm) 10 H2 (sccm) 5,000 (wafers 1^4); 3,750 (wafers 5-9) Ar~on (slm) 0.5 (wafers 5-9) RF Power (watts) 250 e~ 450 ~z Reacion Chamber Pressure ~orr) 51 (Pl~) 6(of~ (5 r,f~) Suscep~or ~otation rau (rpm) 100 Substrate Temp. (C) 565 Deposilion ime (sec) 300 (600 for wafer 9) Susceptor T~ (C) A~ 650 TAB~E 4 WAFER NO.
Results and 1 2 3 4 5 6 7 ~ 9 Additional Parameters rlN layer 798 1076 43.4 89.5 912.2 1082 656.5 m.l 1302 thi~ness (A~
Deposition 21S0 9.1 17.9 .82.5 2165 1313 115.4 ,,3~,,Rate 159.0 (A/min) I~Lyer 53.8 32.6 216. 377. 89.2 25.7 212. 211. 170 Resistinty 4 6 1 1 3 7 3 .1 ~n ~m) Table S shows additional nms made with the ~creased H2 flow and i~crease deposit~on pressu~
Deposiion Pa~ameters for Ta~le No. S
rlcl, (sccm) 10 H2 (sccm) 3,750 Ar~on (slm) 05 RF Power (watts) 250 ~21450 K~z Reacion Chamber Pressure~To.-r) S ~ 5 ~ r~f) Susceptor Rot~tion R~u (rpm) 100 D~ n~ n tim-- (sec) 300 (wafers 9-12 600 seconds) Substrate T~ (C) 565 Susceptor T. ~ (fC) ~50 AMENDED 91~E~T

~ ~ o ~ o ~ C ~
WO 95J33868 2 ~ 9 1 ~ S 6 ~ ~ P~IUS94~13654 r ~ ~
TABJ F NO. 5 WAFER NO.
2 3 i 5 6 7 8 9 10 11 12 ll 7.~ I~r U9.6 394~ ~10.3 451.6 66.2 3-5.6 3-71 2633 792 5 5U.~ 7.19J 7~A
bi~
~) D_177.9 7~.9 ~C2.~ 91J 93.2 77.: ~9.6 ~2J 79,3 9~-9 75,0 7~A
,,4~=, .m3~.7~ 2~3.- 27~.1 211,0 2~0,1 5~5,1 9-1 31--1 2m~ _ _ (~.0~) ~ Gb~ ~
The change ~n deposition pressure fr~(l Torr to S Torr) produced a more stable and symmetric p ~ma Addiionaily, the increas~ed hydrogen flow with the ~dltion of a small flow of argon increased the sta~ility of the plasma flow as well as the plasma intensity. An argon flow of ~10 slm is preferahle. Wafe~s 1-2 were silicon, whi~e wafers 3-10 were thermai o~ide. Wafers 11 and 12 were b~ l ~si~icate glass, availa'ole from Thin Films, Inc. of Freemont, California. None of the wafers of either Ta~71e 4 or 5 were annealed with a~ ammonia plasma annea~.
Table 6 shows additional deposition runs at a susceptor c of 450 C.

.

~ r ~ ç n ~ ~ f C .
WO 95/33861 ~ --~ ~ ' PCrrUS94~1,3,614 . G ' f De~osition P~r~mrt~s for T~hle No 6 rlcl, (sc~m) 5 H2 (sccm) 3,750 Argon (slm) 0.3 RF Power (war~) 250 ~ 450 KEI~
Reaction chamber pressure~(Torr) 51 Susceptor Rotarion Rate (rpm) 100 Deposiion tune (sec) 180 Substrate T ~ (C) a~ Glsly 400C
Susceptor T, ~ r (C) 450 TARr F NO. 6 WAFE~ NO.
Results and 1 2 3 4 5 6 7 Additiorfal Paramet~ rs N layer 242 222 210 241 168 136 150 thiclmess (A) Depasi~2cll 80.7 ~4.0 70.0 8Q3 56.0 453 50,0 R31c (Al~) I yer 66.0 554.0 494.0 714.0 484.0 0.1 0.1 R3~ ty ~a~) Wafers 1-4 were si~icon, wafer 5 was thermal o~de, whil wafers 6 and 7 wefe ~luminum alloy containing aluminum silicon and copper. Runs 6 and 7 of Tahle 6 i8ustrate the nability of depositing a titanium-containing film on aluminum using the present invenion. The deposition runs of Table 6 utili7ed a lower fiow of rea_tant gas tnan tne runs of Table 5, i.e., 5 sccm of TiCI~.
The d ~ c runs of Table 7 were rnade at f~lrther ~MEN~I~ ~ItE~T
...... ... ..... , . . _ _ _ _ _ O (. O .; C C G ~ O C -woss/33s6s 2191456 i I rc~lus94ll3G~ c reduced rlCl flow ta es. All of the wafers of Tablc 7 wcre the~mal o~ide.
None of the wafers of Tablcs 6 or 7 were annealed wi~h an RF a~nmo;~ia , . ., _, _ anneaL

DeDosi~ion Parameters for T;~hle No. 7 rlCL (sccm) wafers 1-2 4 sccm; 3~ 3 sccm; 5~ 2 sccm; and wafer 7 at 1 sccm H2 (sccm) 3 750 RF Power (wa~ts) 250 ~ 450 EC~z ReactionCh~unberPressurei(Tor~ 51 (~) 6(~ (~
Susceptor Rota~on Pale (rpm) 100 Deposi~ion time (sec) 300 (wafers 1 and 2 at 180 and 240 Lc~
Substratc T~ r. (C) ~JIJ~U~ Gi~l~ 400C
SusCeDtor T~ (C) 450 TABLE ~Q. 7 WAFER NO.
Results and 1 2 3 4 5 6 7 Add~ional Para~neters TiN layer gg 132 158 149 ~sg 166 107 thic~ess (A) DeDosit~on 30 33 32 32 3Z 33 21 Rate (A/mir) La~er z5g Z39 199 199 Igo 2~g 4g2 Resistivity ~n -cm) Fig. 6 shows an alte~ative ' ~ of the present invention which eliminates the metal cyLnder 60 and insu}ator ri~.g 62 whi~e p~enting elect~ical arcing inside of the cylinder assemb~y pro~imate tlle RF line and preYenting the undesired formation of pL~sma within the cylinder assembly when the SIIU.. is biased as an electrode. The AMEN~D ~I~EET

~WO 95/33868 2t g~ ~S 6 PCT/US94/13614 .'..~I;. .. i- of Fig. 6 utilizes a housing similar to housing 22 of Fig. 4 which indudes a housing cover 160 and includes an RF supply assembly 162, a heat pipe assembly 164 with cooling jac~et 165 and fluid supply lines and a gas distributor cover 166 with a sealing assembly 168 all generally similar to the respective . of Fig. 4. However, the cylinder assembly 170 does not include a metal cylinder 60 and insulator ring 62. Rather, a cylinder 172 made of insulating material such as quartz surrounds the RF feed line assembly 174.
Cylinder 172 is preferably formulated out of a high quality quartz such as Quartz T08-E available from Hereaus Amersil, as mentioned above. Quartz cylinder 172 is supported by a sl,u.._lh~/dectwde 176, made of a conductive metal such as Nickel-200, without the use of screws or other fasteners that are utilized within the of Fig. 4. Specifically, a stepped bore 178 is formed within housing cover 160 to receive an upper end 177 of cylinder 172. ~rings 179, 180 are placed at the interface 1~1 between stepped bore 178 and cylinder 172 to form a seal at interface 181. At the lower end 184 of cylinder 172, an annular notch 186 is formed in cylinder 172 to receive a peripheral edge 188 of the ' .._.h~i/._l~hu~c 176. The notch 186 of cylinder 172 rests upon the peripheral edge 188 of ~.u... '/el~hu~
176. S~ .h~/electrode 176 includes a stem 194 which is attached to RF line tubing 175 such as by a weld at 195 to form a unitary RF line 197.
RF line is frictionally held and supported at its top end by collar 199 similar to collar 150 of Fig. 4. The RF line, in turrl, supports , i, .

0 95133868 . PCTIUS94/13614 ~ 2191~6 '/electrode 176 above susceptor 182. Showerhead/electrode 176, in turn, supports the cylinder 172 within the cylinder assembly 170 by abutting against cyLinder 172 at shelf notch and holding it in bore 178.
The interface between ' ' '/el~llud~ peripheral edge 188 and cyLinder notch 186 is sealed by a _ ' ~ring 190 which is Cu".~ 1 between notch 186 and a ~ L. annular notch 193 formed in peripheri 1 edge 188. Similar to the . ' ~ ' of Fig. 4, a plurality of gas halos or rings 191, 192 introduce the necessary plasma and reactant gases into cyLinder 172.
The L ' of Fig. 6 eliminates the need for metal screws to attach the cyLinder 172 to the housing 160 and the ~h.,..~ ~dlelectrode 176 to the cylinder 172. This further reduces the possibility of arcing inside of cyLinder 172 because of the reduced metal pro~imate the biased RF ~I~v ' 'lelectrode 176. r~ . it is not necessary to utiLize cerarnic isolator sleeves at the ~ ,.. ' ' peripherial edge 188.
Accordingly, the RF !' .._ ' ~/electrode 176 has also been modified. As shown in Figs. 6 and 7 ~Ilu.._..l~d/electrode includes a stem 194 without a flange. Instead, a slight ridge 196 is formed around stem 194, and as shown in Fig. 6, ridge 196 supports a generally circular ceramic tray 198 which is forrned from a ceramic material similar to the ceramic isolator sleeves 94, 96 shown in Fig. 4. Cerilmic tray 198 is supported by ridge 194, and in turn, supports isolator sleeves 200, 201.
Isolator sleeves 200, 201 are also preferably made of a ceramic insuLator ~ ~ n c o ~ c r~ c W0 95133868 ' ~ Pl~tUS941136i4 . ' r 219145~i rnaterial similar to sleeves 94, 96 of Flg. 4. Around the peripheral edge 188 of ,4u. " ' 'lelectrode 176, shelf 193 is fo~ned to receive ~nng 190 and seal the interface between cylinder l72 and ,I.u . I.~lelectrode 176 as discussed Gas disp~sion holes 206 are formed ~vithin an area 204 sirnilar to the dispersion hole area 156 of thc ,I.u _.I.~i/dectrode shown O.~q~
in Fig. 4. Preferably the holes are ~UlU~lllG~ 32 (0.0313) inches)in diam~ter to prevent the formation of a plasma inside cyiinder 172 to confine the plasma generally bdow the ,i,u.._.i.~ilelectrode 176 and above the susceptor 182 as already discussed above. The I ,~ of Fig. 6 utilizes cylinder In and eliminates the me~i t~hm~tlt screws pro~imate ,.Iu.._.;l~dlelectrode 176 which hdps to prevent the form tion of a plasma within cylinder I72 and to prevent arcing between the RF line 17~ and ,IIu..~I.~ildectrode 176 and any of the ,~.u,...l;..~ metal. A
layer of insulation 208 may be placed atop gas distributor cover 166 to prevent contact by an opetator, because the gas distributor cover 166 becomes very hot during operation.
While the present invention has been illustrated by the description of ~ ~.,1.~1,",. ..1~ thereof,~nd ~hilo ~e ~..b "~
describ= ~Applicants to L Ul .1 Gll~ ..~L Ih~. ~ Of ~~-rr_.;i~ claims to F~
rdditional advantages and ,, ~ will readily appear to those s~ ed in the ar~ For e~ample, the cylinder and ~llu~.~-l~i utili~ed irl one of the preseM invention might be fabricated from a different met I than disclosed. r.. Il .. ,... Ilr, the non-conductive cylinder arld ring ~5END~D 9H~T

Claims

CLAIMS:

1. Apparatus for deposition of a film on a substrate inside a chemical vapor deposition chamber comprising:
a rotatable susceptor adapted to support and rotate a said substrate inside a said chamber, and to create a pumping action to draw reactant gases toward the substrate;
a gas-dispersing showerhead opposite the susceptor and having holes adapted to disperse reactant gases; and a reactant gas supply element for supplying reactant gas to be dispersed from the showerhead, CHARACTERISED IN THAT
the showerhead is spaced about 25mm (one inch) or less from the susceptor and a said substrate, and the supply element is spaced from the showerhead such that a generally linear reactant gas flow is obtainable between the supply element and showerhead to yield improved reactant gas flow over a said substrate and more efficient chemical vapour deposition of a film thereon.

2. Apparatus of Claim 1 comprising a hollow cylinder located between the supply element and the showerhead and having a first end coupled to the supply element and a second end coupled to the showerhead to contain the linear gas flow between the supply element and showerhead.

3. Apparatus of Claim 1 or Claim 2 comprising an RF energy source coupled to the showerhead for biasing the showerhead as an RF electrode, the showerhead electrode being operable to excite reactant gas from the supply element to form a plasma for depositing a film on said substrate by plasma enhanced chemical vapour deposition.

4. Apparatus of Claim 3 wherein a concentrated plasma is generable proximate the susceptor and substrate.

5. Apparatus of Claim 4 and Claim 3 as appendant to Claim 2 comprising a non-conductive,element coupled between the cylinder and the showerhead electrode to prevent biasing of the cylinder with RF energy.

6. Apparatus of Claim 5 wherein the non-conductive element is a ring connected between the second end of the cylinder and a peripheral edge of the showerhead electrode.

7. Apparatus of Claim 5 or Claim 6 wherein the non-conductive element is formed of quartz.

8. Apparatus of Claim 3 comprising an RF line connecting the RF energy source to proximate the centre of the showerhead electrode to bias the showerhead electrode uniformly.

9. Apparatus of Claim 8 and Claim 3 as appendant to Claim 2 wherein a concentrated plasma is generable proximate the susceptor and substrate, and a portion of the RF line extends through the cylinder to the showerhead electrode.

10. Apparatus of Claim 9 wherein the RF line includes a non-conductive covering over the portion of RF
line extending through the cylinder to insulate said RF
line portion and prevent formation of a plasma within the cylinder.

11. Apparatus of Claim 4 and Claim 3 as appendant to Claim 2, or Claim 9 wherein the cylinder is formed of a non-conductive material to prevent biasing of the cylinder with RF energy.

12. Apparatus of Claim 11 wherein the non-conductive material is quartz.

13. Apparatus of any of Claims 3 to 12 wherein the holes of the showerhead electrode are about 0.79mm (1/32 of an inch) in diameter to confine the plasma to one side of the showerhead electrode between the susceptor and the showerhead electrode.

14. A method for depositing a film on a substrate by chemical vapour deposition comprising:
positioning the substrate within an enclosed chamber;
introducing reactant gases into the chamber opposite the substrate through a reactant gas supply element spaced from the substrate;
positioning a gas-dispersing showerhead with gas-dispersing holes between the supply element and the substrate and facing the substrate; and rotating a said substrate to draw the reactant gases to the substrate through the showerhead, CHARACTERISED IN THAT
the showerhead is positioned about 25mm (one inch) or less from the substrate and spaced from the supply element to create a generally linear reactant gas flow between the supply element and the showerhead, to yield improved reactant gas flow over the substrate and more efficient chemical vapour deposition of a film on the substrate.

5. The method of Claim 14 comprising:
coupling a hollow cylinder between the supply element and the showerhead and directing the reactant gases through the cylinder to confine the gases over the showerhead.

16. The method of Claim 14 or Claim 15 comprising:
biasing the showerhead with RF energy as an electrode; and exciting the reactant gases with the showerhead electrode to form a plasma and deposit the film on the substrate by plasma enhanced chemical vapour deposition.

17. The method of Claim 16 wherein the gas-dispersing holes of the showerhead are dimensioned such that the plasma is generally confined to a side of the showerhead electrode facing the substrate to concentrate the plasma near the substrate.

18. The method of Claim 16 wherein the gas-dispersing holes of the showerhead are about 0.79mm (1/32 of an inch) in diameter.

19. The method of Claim 16 wherein a concentrated plasma is generated proximate the showerhead.

20. The method of Claim 19 and Claim 16 as appendant to Claim 15 comprising:
electrically insulating the showerhead electrode from the cylinder to prevent biasing of the cylinder with RF energy from the showerhead electrode.

21. The method of Claim 20 wherein the step of electrically insulating includes coupling an insulative member between the cylinder and showerhead electrode.

22. The method of Claim 21 wherein the insulative member is formed of quartz.

23. The method of Claim 19 and Claim 16 as appendant to Claim 15 wherein the cylinder is formed of non-conductive material to prevent biasing of the cylinder with RF energy from the showerhead electrode.

24. The method of Claim 23 wherein the non-conductive material is quartz.