CN102931045B - The processing method of etching technics pilot signal and etching terminal control method - Google Patents
The processing method of etching technics pilot signal and etching terminal control method Download PDFInfo
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Abstract
A kind of processing method of etching technics pilot signal and etching terminal control method, wherein, processing method comprises: according to the changing condition of signal strength signal intensity, the change curve of real-time etching signal intensity of reflection plasma etching industrial is divided into initial period, stablize the stage of reaction, etches termination phase and etching completes the stage; In the stable stage of reaction, mark benchmark judging area, benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal of benchmark judging area and described etching termination phase; Benchmark judging area is divided into n time zone, obtains the mean value of etching signal intensity in each time zone, wherein n gets the integer being greater than 1; Using the fiducial value that the maximum in all mean value or minimum value judge as etching terminal signal.Method provided by the invention reacts the plasma etch process in reality accurately, and can be suitable for the needs of various different situations.
Description
Technical field
The present invention relates to semiconductor etching process, particularly relate to a kind of processing method and etching terminal control method of plasma etch process pilot signal.
Background technology
Along with the continuous increase of device integration density in integrated circuit and complexity, more strict requirement is proposed to the control of semiconductor processes.And reaction chamber is after running after a while, and the state of its inside can change, and as the parameters such as plasma density, electron temperature, free radical density, gas flow and silicon temperature are often drifted about, this can affect the carrying out of etching technics.Therefore, need the ruuning situation in plasma etching cavity to monitor, and FEEDBACK CONTROL is carried out to etching process, and then ensure stability and the consistency of etching technics.
Optical emission spectroscopy (OES) is a kind of common etching technics control method.Atom in plasma or molecule, by after electron excitation to excitation state, are turning back to the light launching specific wavelength in another energy state process.The wavelength of light wave that excites of homoatomic or molecule is not different, and the change of the light intensity of light wave reflects plasma Atom or molecular concentration change.The characteristic spectral line (OES characteristic spectral line) that OES can reflect plasma etching change in process, form the plasma of closely-related material with plasma chemistry extracts, by detecting the change of its characteristic spectral line signal strength signal intensity in real time, there is provided the information of the response situation in plasma etch process, the method for the actual conditions in accurate response etching process.
Plasma etching process is generally divided into etching to start-stable reaction-etching end 3 processes, indoor at plasma etch chamber, reactant in plasma and product radical concentration can change in etching beginning and etching terminal place, in the process of stable reaction, reactant and product radical concentration substantially constant.Accordingly, the change of real time spectrum signal (OES characteristic spectral line) can be divided at least 3 stages: light plasma portion-the stablize stage of reaction-reaction and stop (etching terminal end point).OES characteristic spectral line and the chemical gas in plasma and the dielectric material etched relevant, and OES characteristic spectral line signal strength signal intensity is directly proportional to reactant and product radical concentration.When lighting plasma portion, etching starts, and the representative radical concentration of reaction product rises, and its intensity of spectral line sharply rises; In the stable stage of reaction, various course of reaction reaches dynamic equilibrium, and the representative radical concentration of reactant and reaction product remains unchanged substantially, and various the intensity of spectral line also remains unchanged substantially; When etching starts to weaken, the concentration of reaction product declines, and the intensity of spectral line sharply weakens; Until etching weakens to after terminating completely, the concentration of reaction product is zero.And the OES spectral line corresponding to etching reactant is when etching beginning, because the etching reactant process of being etched consumed, its characteristic spectral line intensity can weaken rapidly, when etching starts to weaken, because the consumption of etching reactant reduces, the intensity of its characteristic spectral line will rise rapidly, after etching terminates completely, because etching reactant is no longer consumed, its characteristic spectral line can remain unchanged.
Consider the complexity of plasma etch process process, OES characteristic spectral line the intensity of spectral line at steady state of certain etching reactant or product is not definitely constant, because it is also relevant with situation with the structure of chamber.Generally, the mean value of the intensity of the characteristic spectral line of a period of time in the whole stable state of etching is adopted to be used as the fiducial value of etching terminal setting.But in fact, actual spectrum strength signal can be subject to the interference of a lot of environmental factor, and so steady unlike ideally.Such method can not state actual conditions completely, and inapplicable in some cases, can cause the misjudgment to etching process change.
Summary of the invention
The object of this invention is to provide a kind of endpoint monitoring suitable that is more sensitive and plasma etch process accurately.
For achieving the above object, the invention provides a kind of processing method of plasma etch process pilot signal, comprising:
According to the changing condition of signal strength signal intensity, the change curve of real-time etching signal intensity of reflection plasma etching industrial is divided into initial period, stablize the stage of reaction, etch termination phase and etching completes the stage;
In the described stable stage of reaction, mark benchmark judging area, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal of described benchmark judging area and described etching termination phase;
Described benchmark judging area is divided into n time zone, obtains the mean value of etching signal intensity in each time zone, wherein n gets the integer being greater than 1;
Using the fiducial value that the maximum in all mean value or minimum value judge as etching terminal signal.
Optionally, described real-time etching signal is the OES characteristic spectral line of reactant in described plasma etch process or product.
Optionally, described real-time etching signal is the differentiate value of the OES characteristic spectral line intensity of reactant in described plasma etch process or product.
Optionally, the terminal of described benchmark judging area becomes positive correlation with the size of the spacing of the starting point of described etching termination phase with the size of the etching error tolerances of the thickness of the rete that is etched.
Optionally, the division that the multiple reactant in comprehensive described plasma etching industrial or the etching signal of product carry out described initial period, stablize the stage of reaction, etching termination phase and etching complete the stage.
Optionally, the span of n is 3 to 10.
Optionally, n is 5.
Optionally, described time zone is the region do not overlapped continuously mutually, and the time of each region experience is 1s ~ 2s.
Present invention also offers a kind of end-point control method of plasma etch process, comprising:
Multiple wafers of same batch are provided;
Choose at least one wafer as sample, plasma etching is carried out to this sample, and etching process is monitored, to obtain the change curve of real-time etching signal intensity;
Utilize aforesaid processing method to process above-mentioned change curve, obtain fiducial value;
Said reference value is utilized to carry out terminal point control to the etching process of other wafer of same batch.
Optionally, utilize said reference value to carry out terminal point control to the etching process of other wafer, comprising: in the etching of other wafer, real-time testing etching signal intensity, when the deviation of the etching signal intensity level recorded and described fiducial value exceeds a threshold value, terminate etching.
Compared with prior art, the present invention has the following advantages:
The present invention by marking benchmark judging area (time window) in the described stable stage of reaction, again described benchmark judging area is divided into n time zone (n is greater than 1), get the mean value of etching signal intensity in each time zone, obtain n mean value, then maximum in a described n mean value is got or minimum value is fiducial value, again the method exceeding described fiducial value etching end variable quantity is used as etching terminal, method provided by the invention reflects the plasma etch process disturbed by various factors more accurately, and the needs of various different situations can be suitable for.
Accompanying drawing explanation
Fig. 1 and Fig. 2 is the schematic diagram of the curve over time of the OES characteristic spectral line intensity of etching reactant in embodiment one;
Fig. 3 is the schematic diagram of the derivative curve over time of the OES characteristic spectral line intensity of etching reactant in embodiment two.
Embodiment
For enabling above-mentioned purpose of the present invention, feature and advantage become apparent more, are described in detail the specific embodiment of the present invention below in conjunction with accompanying drawing.
Set forth a lot of detail in the following description so that fully understand the present invention.But the present invention can be much different from alternate manner described here to implement, those skilled in the art can when without prejudice to doing similar popularization when intension of the present invention, therefore the present invention is by the restriction of following public concrete enforcement.
The etching terminal defining method of plasma etch process provided by the invention comprises the following steps: the wafer providing same batch, the surface of described same batch of wafer has identical semiconductor device structure, and follow-up needs carries out identical plasma etch process; At least a slice of getting wherein is put into plasma reaction chamber as sample and is carried out plasma etching, and monitors etching process, to obtain the change curve of the OES characteristic spectral line intensity of whole etching process; Analyze whole process (such as, dividing each stage of etching: initial period, stablize the stage of reaction, termination phase) according to the change curve of the OES characteristic spectral line intensity obtained, set rational etching terminal position according to the needs of technique; Etching terminal according to setting carries out etching terminal control to the plasma etch process of other wafer of described same batch.Wherein, the degree of the etching on the change curve of the OES characteristic spectral line intensity of whole plasma etch process here representated by each section (such as initial period, stablize the stage of reaction etc.) can obtain corresponding checking by real-time physical verification (such as judging the thickness of tangent plane with ESEM) again.
Wherein, on the change curve of OES characteristic spectral line intensity, etching termination phase is a process, from the stable stage of reaction of etching technics, the state of OES characteristic spectral line intensity held stationary terminates, to this section process of OES characteristic spectral line intensity again in the middle of held stationary after etching terminates completely, all to calculate and etch termination phase.
And in the etching technics of actual production, the point that must be had to determine is used as stopping the control signal of etching technics as etching terminal, with can better Controlling Technology.Using the mean value of the intensity of spectral line of the whole stable stage of reaction as fiducial value, and will can reach the point of a certain threshold value (being empirical value, 20% of such as fiducial value) in termination phase at first with the deviation of this fiducial value as etching terminal under normal circumstances.
But this rigid terminal defining method can ignore the difference of different demand in reality, be difficult to ensure best etching effect.Such as, guarantee as needed the rete that etches be etched totally, even preferably can carry out over etching, just need etching terminal to arrange comparatively rearward in theory; And if the rete of needs etching is very thin, and try not to cause damage to lower floor, just need etching terminal to arrange forward.
For the demand, invention further provides a kind of defining method of fiducial value of the stable stage of reaction of plasma etching process, the situation time fiducial value found according to the method can represent that etching reaction is stablized accurately and the needs of various different situations can be suitable for.The method specifically comprises:
Obtain the real-time etching signal intensity in plasma etching chamber;
According to the change of signal strength signal intensity, described plasma etching industrial is divided into initial period, stablizes the stage of reaction, etching termination phase and etching complete the stage;
Benchmark judging area (time window) is marked in the described stable stage of reaction, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal of described benchmark judging area and described etching termination phase;
Described benchmark judging area is divided into n time zone (n be greater than 1 integer), get the mean value of etching signal intensity in each time zone, obtain n mean value;
Using the fiducial value that the maximum in n mean value or minimum value judge as etching terminal signal.
Said reference value defining method is described in detail below by specific embodiment.
Embodiment one
Step S1: obtain the real-time etching signal intensity in plasma etching chamber;
The described real-time etching signal obtained can be the OES characteristic spectral line of the change in concentration situation of etching reactant or product in reflection etch chamber.Intercept in plasma etching chamber the change of the light intensity of wave that the plasma of certain reactant or etching product in the whole process of etching of carrying out or plasma group send.As adopted HBr/Cl
2in the reaction of etch polysilicon, can detecting reactant HBr or Cl
2change in concentration, also can detect the change in concentration of volatility etching product SiCl.The signal of detecting reactant in the present embodiment, obtains the situation of its change as shown in curve in Fig. 1.Wherein transverse axis is time T, and the longitudinal axis is OES characteristic spectral line intensity I v.
Those skilled in the art it is understood that, etching on whole wafer, not identical everywhere, even if be in stable etch stages at the film be etched, reactor wall is sedimental gradually to be generated or gradually discharges, and all can cause the slow change of the intensity of OES characteristic spectral line in the steady state.Other factors relevant to plasma reaction, also all can change the intensity of OES characteristic spectral line.Show in the time dependent curve of OES characteristic spectral line intensity and be, at close etching termination phase C place, the OES characteristic spectral line intensity of reactant raises gradually; After entering etching termination phase C, OES characteristic spectral line intensity is with amplitude rising faster; Finally, OES characteristic spectral line intensity tends to be steady, and indicates that etching completes.
Step S2: according to the change of signal strength signal intensity, described plasma etching industrial is divided into initial period, stablizes the stage of reaction, etching termination phase and etching complete the stage;
Continue with reference to shown in figure 1, from zero point, along with time variations, the described curve representing etching signal mainly experienced by four-stage: the stage sharply declined, change be stage of some fluctuation, the stage gradually raised and the stage steadily no longer raised more gently but once in a while.They respectively corresponding initial period A, stablize stage of reaction B, etching termination phase C and etching complete stage D.Wherein, the boundary of initial period A and stable stage of reaction B is the place that in closer that section of curve started most, rate of change reduces suddenly, stablize boundary between stage of reaction B and etching termination phase C for after entering stable stage of reaction B a period of time, curve produces suddenly near larger transition place, and etching termination phase C and the boundary having etched stage D are the initial of last that section of curve completely stably.In reality, due to reasons such as disturbing factor in etching cavity are too many or etching area is smaller, the etching signal impact that is interfered is larger, and itself is fainter again simultaneously, and the change of curve is not too obviously, and the boundary in these regions is not so obvious.Can detect the signal intensity of many kinds of substance in the reaction of described plasma etching, obtain many curves, the variation tendency weighing many curves considers the boundary deciding each stage.Preferably, the many kinds of substance detected can comprise etching reactant and etching product, because the change of etching reactant and product is roughly contrary, especially near etching terminal, the place can intersected with the change curve of the etching signal of etching product with etching reactant, as an important references point of boundary.
Step S3: mark benchmark judging area (Time window) in the described stable stage of reaction, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal of described benchmark judging area and described etching termination phase;
Because plasma reaction chamber environment is complicated, in stable state, the concentration of etching reactant or product always has various change.The size of change also fluctuates by the fluctuation of instant environment.And etching signal is more weak, be also easily subject to the impact of other factors, these other factorses are referred to as " noise ".The etching signal obtained in reality must be constantly have fluctuation, just presents certain trend substantially, as has been described above, is generally used as fiducial value by trying to achieve mean value.Wherein, being averaging is a kind of method of anti-noise, because noise is occurrent, being averaging is that the accidental impact of noise is loosened in whole interval of averaging, thus reduces the fluctuation that noise causes, and gets rid of the interference of noise.
The method of this step can referring again to Fig. 2, and the reactant OES characteristic spectral line intensity I v in a period of time interval in stage of reaction B is stablized in intercepting, and the region intercepted is as benchmark judging area (being designated as TimeWindow).The intercepting scope of Time Window is in the stable stage of reaction of plasma etch process, and because the present embodiment is the fiducial value needing searching one to judge etching terminal, described Time Window chooses preferably close to the section start of etching termination phase C.General, the size of the error tolerances of the thickness of the terminal of described Time Window and the size of the spacing L of the starting point of described etching termination phase and the described rete that is etched is relevant.The distance L of Time Window and terminal is less than the etch period of the admissible error needs of thickness.
The time span of Time Window judges according to the time span of concrete whole etching reaction process, and time noise effect is not very large, Time Window can get a little bit smaller, and time noise effect is very large, Time Window can get greatly a bit.Time Window accounts for 30% ~ 80% of the described stable stage of reaction and is advisable.Generally, Time Window gets more than 5s.If etching reaction process is very long, adaptively can get the longer time, so that the concentration of etching process reactant better can be represented.
Step S4: described benchmark judging area is divided into n time zone (n is greater than 1), gets the mean value of etching signal intensity in each time zone, obtain n mean value;
According to the time span of Time Window intercepted, adaptively n(n is divided into be greater than 1 Time Window) individual time zone, the numerical value of n is suitable can differentiate being changed to of course of reaction accurately.In the present embodiment, especially need to tell the situation of change gradually risen close to etching terminal moment reaction substrate concentration accurately.In addition, n value is too large, and calculating can be made lengthy and jumbled, and deterministic process is too slow.Preferably, n value is 5, then Time Window is divided into T1, T2, T3, T4 and T5 five time zones altogether.
According to the change of the OES characteristic spectral line intensity I v in each time zone, obtain the mean value in each region, obtain mean value I1, I2, I3, I4 and I5 corresponding in each time zone.
Step S5: get the fiducial value that maximum in n mean value or minimum value judge as etching terminal signal again.
Wherein get the fiducial value which type of value judges as etching terminal signal to select according to the needs of concrete technology.In etching reaction stops as controlled in time at needs, maximum can be selected as fiducial value, and needing over etching with when guaranteeing that the material needing to etch away etches away completely, minimum value can be selected as fiducial value.Mode in the present embodiment, can provide various selection to meet different process control needs.
As shown in Figure 2, I1, I2, I3, I4 and I5 increase successively, wherein closest to OES characteristic spectral line intensity curve in figure transition place be maximum I5.Getting I5 is fiducial value, as the fiducial value judging etching terminal.In other etching reaction, the disturbing factor that is subject to is different, and I1, I2, I3, I4 and I5 might not be the relations increased successively, and it may be that other unexpected transition in value position except I5 becomes maximum.Such method is compared with the method for fiducial value with directly adopting the mean value of the stabilization process of whole etching, can not cause misjudgment.If certain etching reaction as described in the embodiment, in its benchmark judging area, in n time zone, etching signal average strength rises continuously, can the fiducial value that judges as etching terminal signal of the maximum of direct selective etching signal strength signal intensity.
In other execution mode, such as detected material is etching product, so in close to etching terminal, the variation tendency of OES characteristic spectral line intensity curve reduces, and the OES characteristic spectral line intensity that etching terminates the rear stable stage of reaction is zero or be close to zero.Under these circumstances, described fiducial value gets minimum value.
After obtaining said reference value, described fiducial value can be utilized to carry out the judgement of etching terminal.Concrete grammar is:
Step P1: obtain fiducial value according to aforesaid method, obtain reference value I 5;
Step P2: determine that etching terminates variable quantity;
Continue with reference to shown in figure 2, by the analysis to curve, confirmablely obtain in whole etching termination phase, the variation delta Iv(of etching reactant its be the deviation having etched stage strength value and fiducial value).According to the needs of etching reaction, determine that etching terminates variation delta Iv', described Δ Iv' is less than Δ Iv.When needing etching terminal forward, described Δ Iv' can arrange smaller, and when needing etching terminal rearward, described Δ Iv ' can arrange larger.
Step P3: setting etching signal intensity level and the deviation of described fiducial value exceed that to etch the point terminating variable quantity be described plasma etch process endpoint signal, and described plasma etch process terminal is at described etching termination phase.
As shown in Figure 2, be fiducial value with I5, the some S that the variable quantity of the etching reactant detected reaches Δ Iv' is set as etching terminal.In follow-up technique, the etching termination of the plasma etch process under similarity condition can be controlled by etching terminal S.
Embodiment two
In actual conditions, because plasma reaction chamber environment is complicated, in stable state, the concentration of etching reactant or product always has various change.The size of change also fluctuates by the fluctuation of instant environment.Floating of such as chamber indoor temperature, or chamber internal gas pressure the small situation such as to float all can cause etching reaction to carry out the fluctuation of situation, and thus the concentration of etching reactant or product changes suddenly and rapidly, and rate of change also can have a fluctuation at short notice.But fainter due to etching signal, the amplitude of the change that some little impact causes is also smaller, and the change curve of direct etching signal makes a decision more unintelligible.And disturb relative to larger etching signal, directly can be bigger than normal as fiducial value with the mean value of the intensity of spectral line of the whole stable stage of reaction, the etching situation of the stable stage of reaction can not be showed accurately.And some small changes can be amplified by differentiate, and the minimum value place of differentiation can obtain the place of whole stable stage of reaction minimum interference.
Be described in detail for the characteristic spectral line intensity measuring etching reactant below.
Step S1: obtain the real-time etching signal in plasma etching chamber;
Over time as shown in Figure 3, wherein transverse axis is time T to the derivative of the OES characteristic spectral line intensity of the described etching reactant of final acquisition, and the longitudinal axis is the derivative Iv' of OES characteristic spectral line intensity.The derivative of OES characteristic spectral line intensity has reacted the situation of substances to be measured rate of change.
Step S2: according to the change of signal strength signal intensity, described plasma etching industrial is divided into initial period, stablizes the stage of reaction, etching termination phase and etching complete the stage;
For the present embodiment, those skilled in the art are it is understood that etching reactant is very large at the rate of change of initial period, and gradually slowly, namely the derivative of its OES characteristic spectral line intensity is also larger, then reduces gradually; Etching reactant is very little at the rate of change of the stable stage of reaction, and namely the size of the derivative of its OES characteristic spectral line intensity is close to zero, and has fluctuation once in a while; Etching reactant starts to become large at the rate of change of etching termination phase, and gradually becomes large, and namely the derivative of its OES characteristic spectral line intensity starts to increase; Etching reactant can not become in the etching stage of completing again, and namely the derivative of its OES characteristic spectral line intensity is zero.Situation in similar embodiment one, curve previous step obtained is divided into initial period A, stablizes stage of reaction B, etching termination phase C and etching complete the stage (not shown).
Step S3: the situation in similar embodiment one, benchmark judging area (Time window) is marked in the described stable stage of reaction, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal of described benchmark judging area and described etching termination phase;
Step S4: described benchmark judging area is divided into n time zone (n is greater than 1), gets the mean value of etching signal intensity in each time zone, obtain n mean value;
Similar with embodiment one, Time Window is divided into T1, T2, T3, T4 and T5 five time zones altogether, obtains the mean value in each region, obtain mean value I1, I2, I3, I4 and I5 corresponding in each time zone.
Step S5: the fiducial value that the maximum in n mean value or minimum value are judged as etching terminal signal.
As previously mentioned, under such circumstances, the mean value of whole Time window is next can be bigger than normal as fiducial value.When stable state, optimal situation can be in whole stable state, and etching reaction is interference-free, then the concentration of etching reactant or product does not change, and the derivative Iv' of OES characteristic spectral line intensity should be zero.And in reality, etching reaction is kept away unavoidably disturbed.Select the place that rate of change is minimum as much as possible, closer to original perfect condition.Therefore be applicable to getting minimum value in the several value of I1, I2, I3, I4 and I5 as fiducial value.
Similar with embodiment one, after obtaining said reference value, described fiducial value can be utilized to carry out the judgement of etching terminal.
Embodiment three
In the present embodiment, the stable stage of reaction time of described plasma etch process is very short, described etching reaction substrate concentration reduces suddenly when etching and starting and does not also enough stablize described etching and just complete, and described etching reaction substrate concentration starts again unexpected rising.For such situation, described in when carrying out the division of benchmark judging area (Time window), its starting point, or/and terminal is difficult to ensure to be in the stable stage of reaction completely, likely can be displaced to initial period or etching termination phase.Further, described benchmark judging area is generally greater than 5s.When the time of described stable stage of reaction time is less than or equal to 6 seconds, the beginning or end of the fiducial value judging area of getting easily exceedes the beginning or end of the stable stage of reaction.When similar above-mentioned, the etching reactant concentration ratio actual conditions of closing in the time zone of beginning or end are higher.Under these circumstances, directly getting the minimum value in benchmark judging area, can be the value of the truth closest to etching reaction.
General, when the time of described stable stage of reaction time is less than or equal to 6 seconds, can the fiducial value that judges as etching terminal signal of the minimum value of direct selective etching signal strength signal intensity.
Similar with embodiment one, after obtaining said reference value, described fiducial value can be utilized to carry out the judgement of etching terminal.
The above is only preferred embodiment of the present invention, not does any pro forma restriction to the present invention.
Although the present invention discloses as above with preferred embodiment, but and be not used to limit the present invention.Any those of ordinary skill in the art, do not departing under technical solution of the present invention ambit, the Method and Technology content of above-mentioned announcement all can be utilized to make many possible variations and modification to technical solution of the present invention, or be revised as the Equivalent embodiments of equivalent variations.Therefore, every content not departing from technical solution of the present invention, according to technical spirit of the present invention to any simple modification made for any of the above embodiments, equivalent variations and modification, all still belongs in the scope of technical solution of the present invention protection.
Claims (11)
1. a processing method for plasma etch process pilot signal, is characterized in that, comprising:
According to the changing condition of signal strength signal intensity, the change curve of real-time etching signal intensity of reflection plasma etching industrial is divided into initial period, stablize the stage of reaction, etch termination phase and etching completes the stage;
In the described stable stage of reaction, mark benchmark judging area, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal of described benchmark judging area and described etching termination phase;
Described benchmark judging area is divided into n time zone, obtains the mean value of etching signal intensity in each time zone, wherein n gets the integer being greater than 1;
Using the fiducial value that the maximum in all mean value or minimum value judge as etching terminal signal.
2. processing method as claimed in claim 1, is characterized in that, described real-time etching signal is the OES characteristic spectral line of reactant in described plasma etch process or product.
3. processing method as claimed in claim 1, is characterized in that, described real-time etching signal is the differentiate value of the OES characteristic spectral line intensity of reactant in described plasma etch process or product.
4. processing method as claimed in claim 1, it is characterized in that, the terminal of described benchmark judging area becomes positive correlation with the size of the spacing of the starting point of described etching termination phase with the size of the etching error tolerances of the thickness of the rete that is etched.
5. processing method as claimed in claim 1, it is characterized in that, the multiple reactant in comprehensive described plasma etching industrial or the etching signal of product carry out described initial period, stablize the stage of reaction, division that etching termination phase and etching complete the stage.
6. processing method as claimed in claim 1, it is characterized in that, the span of n is 3 to 10.
7. processing method as claimed in claim 6, it is characterized in that, n is 5.
8. processing method as claimed in claim 1, is characterized in that, described time zone is the region do not overlapped continuously mutually, and the time of each region experience is 1s ~ 2s.
9. processing method as claimed in claim 1, it is characterized in that, when in described benchmark judging area, in n time zone, etching signal average strength rises continuously, the fiducial value that the maximum in selective etching signal strength signal intensity mean value judges as etching terminal signal.
10. an end-point control method for plasma etch process, is characterized in that, comprising:
Multiple wafers of same batch are provided;
Choose at least one wafer as sample, plasma etching is carried out to this sample, and etching process is monitored, to obtain the change curve of real-time etching signal intensity;
Utilize processing method as claimed in any one of claims 1-9 wherein to process above-mentioned change curve, obtain fiducial value;
Said reference value is utilized to carry out terminal point control to the etching process of other wafer of same batch.
11. end-point control methods as claimed in claim 10, it is characterized in that, said reference value is utilized to comprise the step that the etching process of other wafer carries out terminal point control: in the etching of other wafer, real-time testing etching signal intensity, when the deviation of the etching signal intensity level recorded and described fiducial value exceeds a threshold value, terminate etching.
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| US9640371B2 (en) * | 2014-10-20 | 2017-05-02 | Lam Research Corporation | System and method for detecting a process point in multi-mode pulse processes |
| CN105097589B (en) * | 2015-05-27 | 2018-08-28 | 上海华力微电子有限公司 | A kind of detection method of metal hardmask integration etching through hole over etching amount |
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| JP2006222373A (en) * | 2005-02-14 | 2006-08-24 | Matsushita Electric Ind Co Ltd | Dry etching system and dry etching method using same |
| CN101465287A (en) * | 2008-12-31 | 2009-06-24 | 中微半导体设备(上海)有限公司 | Method for etching plasma |
| CN102347197A (en) * | 2011-10-31 | 2012-02-08 | 中微半导体设备(上海)有限公司 | Method for dynamically detecting etched end point |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6599759B2 (en) * | 2001-05-02 | 2003-07-29 | Taiwan Semiconductor Manufacturing Co., Ltd | Method for detecting end point in plasma etching by impedance change |
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2012
- 2012-10-18 CN CN201210398754.8A patent/CN102931045B/en active Active
- 2012-11-30 TW TW101145137A patent/TW201417169A/en unknown
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| US4198261A (en) * | 1977-12-05 | 1980-04-15 | Gould Inc. | Method for end point detection during plasma etching |
| US5582746A (en) * | 1992-12-04 | 1996-12-10 | International Business Machines Corporation | Real time measurement of etch rate during a chemical etching process |
| JP2001059193A (en) * | 1999-08-24 | 2001-03-06 | Nippon Telegr & Teleph Corp <Ntt> | Production of x-ray mask, and device therefor |
| JP2006222373A (en) * | 2005-02-14 | 2006-08-24 | Matsushita Electric Ind Co Ltd | Dry etching system and dry etching method using same |
| CN101465287A (en) * | 2008-12-31 | 2009-06-24 | 中微半导体设备(上海)有限公司 | Method for etching plasma |
| CN102347197A (en) * | 2011-10-31 | 2012-02-08 | 中微半导体设备(上海)有限公司 | Method for dynamically detecting etched end point |
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| TWI471933B (en) | 2015-02-01 |
| TW201417169A (en) | 2014-05-01 |
| CN102931045A (en) | 2013-02-13 |
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