CN100468640C - Etching method and contact window forming method - Google Patents
Etching method and contact window forming method Download PDFInfo
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- CN100468640C CN100468640C CNB2005100794191A CN200510079419A CN100468640C CN 100468640 C CN100468640 C CN 100468640C CN B2005100794191 A CNB2005100794191 A CN B2005100794191A CN 200510079419 A CN200510079419 A CN 200510079419A CN 100468640 C CN100468640 C CN 100468640C
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Abstract
The related etching method comprises two steps, while the temperature on the second step is higher than the first. Thereby, this invention can form small final size.
Description
Technical field
The present invention relates to a kind of engraving method, particularly relate to a kind of engraving method that dwindles critical size.
Background technology
Under the more and more high situation of integrated requirement, the design of whole semiconductor element size develops on minification.The technology of integrated circuit is the method for pattern lines apart from downsizing, is mostly to utilize to have high-resolution photoetching process and reach.But high-resolution photoetching process since the restriction of essential optics so technology comparatively difficulty and cost are also comparatively expensive.
A kind of etch process method is arranged at present, can not need utilize high-resolution photoetching process to reach to dwindle the purpose of the critical size after the etching.The method forms the back of developing with existing photoetching process and checks critical size (ADI CD), use the rich in polymers (polymer rich) and the prescription of low-power (lower power) to carry out etching afterwards, so that the critical size that the critical size of checking after the etching is checked less than the back of developing.Yet, when carrying out etching, cause the problem of photoresist layer and anti-reflecting layer enlarging easily, and make the critical size of the opening after the etching can't reach required person with the method.On the other hand, for the critical size that dwindles after the etching its limit is arranged with this engraving method, therefore if can't effectively dwindle critical size, distance between formed contact window can be too approaching, overlapping part can appear even, and make the contact hole of follow-up formation produce the phenomenon of bridge joint easily, make the reliability decrease of element.
Summary of the invention
Purpose of the present invention is providing a kind of engraving method exactly, can effectively dwindle the critical size after the etching.
A further object of the present invention provides a kind of engraving method, can dwindle the live width of critical size, to improve the integrated level of integrated circuit.
Another purpose of the present invention provides a kind of formation method of contact hole, can avoid the bridge joint phenomenon of contact hole, to improve the reliability of semiconductor element.
The present invention proposes a kind of engraving method, is applicable to the semiconductor-based end, has dielectric layer and anti-reflecting layer on its surface in regular turn, at first forms patterning photoresist layer on anti-reflecting layer.Then, be mask with patterning photoresist layer, carry out first etching step, to remove the anti-reflecting layer that exposes at least.Then, as mask, carry out second etching step, with patterning photoresist layer and anti-reflecting layer to remove the part dielectric layer.Then, remove patterning photoresist layer.Wherein, first etching step carries out under different temperature with second etching step.
Described according to the embodiment of the invention, the temperature of above-mentioned first etching step is lower than the temperature of second etching step.The temperature of first etching step is lower than temperature 5-20 ℃ of second etching step.The temperature range of first etching step is included between 0 ℃～30 ℃.The temperature range of second etching step is included between 30 ℃～50 ℃.In addition, first etching step can carry out in different reaction chambers with second etching step.
Described according to the embodiment of the invention, above-mentioned engraving method can form the polymer clearance wall on the sidewall of patterning photoresist layer in the process of carrying out first etching step.
The present invention proposes a kind of formation method of contact window, and a substrate at first is provided, and has been formed with conduction region in substrate.Then, in substrate, form dielectric layer and cover conduction region.Then, on dielectric layer, form anti-reflecting layer.Next, on anti-reflecting layer, form patterning photoresist layer.Afterwards, be mask with patterning photoresist layer, carry out first etching step, to remove the anti-reflecting layer that exposes at least.Continue it, as mask, carry out second etching step to remove dielectric layer and to expose conduction region with patterning photoresist layer and anti-reflecting layer.Then, remove patterning photoresist layer.Wherein, first etching step carries out under different temperature with second etching step.
Described according to the embodiment of the invention, the temperature of above-mentioned first etching step is lower than the temperature of second etching step, and the temperature of above-mentioned first etching step is lower than the temperature of second etching step at least more than 5-20 ℃.The temperature range of first etching step is between 0 ℃～30 ℃; The temperature range of second etching step is between 30 ℃～50 ℃.
Described according to the embodiment of the invention, use the first fluorine-containing hydrocarbon compound in above-mentioned first etching step, in second etching step, use the second fluorine-containing hydrocarbon compound.
Described according to the embodiment of the invention, in the formation method of above-mentioned contact window, the first fluorine-containing hydrocarbon compound comprises tetrafluoromethane, and can also comprise the mist of octafluoro butylene and hexafluoro butine.In addition, employed etching gas can also comprise carbonoxide or oxygen.Second etching step comprises main etching step and over etching step.The main etching step employed second fluorine-containing hydrocarbon compound comprises fluoroform, difluoromethane, and can comprise fluoromethane again, can add argon or oxygen more in addition.The over etching step employed second fluorine-containing hydrocarbon compound comprises hexafluoro butine, octafluoro pentyne or octafluoro butylene, and can also comprise oxygen or argon.
Described according to the embodiment of the invention, in the formation method of above-mentioned contact window, first etching step is included in the different reaction chambers with second etching step and carries out.
Described according to the embodiment of the invention, the formation method of above-mentioned contact window is included in the process of carrying out first etching step, can form the polymer clearance wall on the sidewall of patterning photoresist layer.
Described according to the embodiment of the invention, the formation method of above-mentioned contact window also is included in and forms before the dielectric layer, forms metal silicide on conduction region.
Described according to the embodiment of the invention, in the formation method of above-mentioned contact window, the material of metal silicide comprises nickle silicide, tungsten silicide or cobalt silicide.
Described according to the embodiment of the invention, the formation method of above-mentioned contact window also is included in and forms before the dielectric layer, forms etch stop layer in substrate, and remove partially-etched stop layer after carrying out second etching step.
Described according to the embodiment of the invention, the formation method of above-mentioned contact window also is included in and forms before the anti-reflecting layer, forms hard mask layer on dielectric layer, and remove the part hard mask layer in first etching step.
Adopt engraving method proposed by the invention to go up the formation clearance wall in patterning photoresist layer sidewall and surface, thus, can be reduced in the consumption of photoresist layer in the etching process, and reduce when the antagonistic reflex layer carries out etching, the problem of the enlarging that produces at photoresist layer and anti-reflecting layer, and the critical size after the development that can be bigger obtains the critical size after the less etching, effectively dwindles the critical size of element.It will be further appreciated that, adopt engraving method proposed by the invention, can effectively improve etching selectivity
On the other hand, according to the formation method of contact hole proposed by the invention, can dwindle the critical size of formed contact window, can be too approaching to avoid the distance between contact window, and prevent that the contact hole of follow-up formation from producing the phenomenon of bridge joint, therefore can improve the reliability of element.
For above and other objects of the present invention, feature and advantage can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. is described in detail below.
Description of drawings
Figure 1A～Fig. 1 F is according to the manufacturing process profile of the contact window that one embodiment of the invention illustrated.
The simple symbol explanation
100: the semiconductor-based end
101: isolation structure
102: gate dielectric layer
104: grid
106: clearance wall
108: source area
110: the drain region
112: metal silicide
114: etch stop layer
115: dielectric layer
116: the non-impurity-doped glassy layer
118: phosphorosilicate glass layer
120: cap layer
122: hard mask layer
124: anti-reflecting layer
126: patterning photoresist layer
128: the polymer clearance wall
130: polymeric layer
132: contact window
Embodiment
Figure 1A～Fig. 1 F illustrates the manufacturing process profile of the contact window of one embodiment of the invention.Figure 1A illustrates the metal-oxide-semiconductor element that is formed at at semiconductor-based the end 100, and this metal-oxide-semiconductor element for example is that shallow slot isolation structure and other element are isolated by isolation structure 101.The grid 104 of metal-oxide-semiconductor element is formed on the gate dielectric layer 102; And clearance wall 106 is formed on the sidewall of grid 104.Source area 108 is formed at drain region 110 at the semiconductor-based end 100 of grid 104 both sides.In another embodiment, also can form metal silicide 112 on grid 104, source area 108 and drain region 110, its material for example is nickle silicide, tungsten silicide or cobalt silicide etc., to reduce resistance.The material of each member of above-mentioned metal-oxide-semiconductor (MOS) and formation method have in this technical field and know that usually the knowledgeable institute is known, repeat no more in this.
Then, please refer to Figure 1B, form dielectric layer 115 and be covered in grid 104, source area 108 and drain region 110 on the semiconductor-based end 100, dielectric layer 115 for example is made up of non-impurity-doped glassy layer 116 and phosphorosilicate glass layer 118.And the formation method of dielectric layer 115 for example is to carry out a chemical vapor deposition method earlier, to form non-impurity-doped glassy layer 116 on the semiconductor-based end 100, carries out another chemical vapor deposition method again, to form phosphorosilicate glass layer 118 on non-impurity-doped glassy layer 116.Wherein, non-impurity-doped glassy layer 116 can suppress moving of phosphorous dopants in the phosphorosilicate glass layer 118, prevents issuable electrical defective.In addition, can form etch stop layer 114 before forming dielectric layer 115, its material for example is a silicon nitride, and the method for formation for example is a chemical vapour deposition technique.Over etching takes place and the situation of destruction source/drain region knot and then generation leakage current in the purpose that forms etch stop layer 114 in the process that prevents follow-up formation contact hole.
Then, please refer to Fig. 1 C, form anti-reflecting layer 124 on dielectric layer 118, its material for example is titanium/titanium nitride (Ti/TiN), and the method for formation for example is a chemical vapour deposition technique.In another embodiment, before forming anti-reflecting layer 124, can form hard mask layer 122 earlier, its material for example is a silicon oxynitride, the method that forms for example is a chemical vapour deposition technique, it act as when patterning photoresist layer 126 and during approach exhaustion, uses to prevent that the below rete is damaged as mask layer in etching process.In addition, can be before forming hard mask layer 122, prior to forming cap layer (cap layer) 120 on the dielectric layer 115, its material for example is a silica, the method that forms for example is to be reacting gas source with tetraethoxysilane (TEOS), utilizes chemical vapour deposition technique to form it.
Next, please refer to Fig. 1 D, on anti-reflecting layer 124, form patterning photoresist layer 126.Afterwards, be mask with patterning photoresist layer 126, carry out first etching step, to remove the anti-reflecting layer 124 that exposes at least.Reaction temperature in this first etching step for example is between 0～30 ℃, uses fluorine-containing hydrocarbon compound as etching gas, for example is tetrafluoromethane.In etching gas, can add mist as octafluoro butylene and hexafluoro butine.In addition, can add as gases such as carbon monoxide or oxygen again according to the characteristic of photoresist.In another embodiment, the dielectric layer 115 of removable anti-reflecting layer 124 of this first etching step and hard mask layer 122, cap layer 120 and a part.
It should be noted that, in another embodiment of the present invention, under the reaction temperature of first etching step, the etching gas that is adopted-fluorine-containing hydrocarbon compound can produce reaction with patterning photoresist layer 126, and forms polymer clearance wall 128 on the sidewall of patterning photoresist layer 126.Thus; polymer clearance wall 128 can be protected patterning photoresist layer 126; slowing down the depletion rate of patterning photoresist layer 126 in etching process, and prevent the enlarging phenomenon that patterning photoresist layer 126 and anti-reflecting layer 124 are produced.Simultaneously, can effectively dwindle the critical size of dielectric layer 115 after etching.In addition, because of the critical dimension reduction of formed contact window, can avoid between the contact hole (not illustrating) of follow-up formation distance too near and produce the bridge joint phenomenon, to improve the reliability of semiconductor element.
Continue it, please refer to Fig. 1 E, as mask, carry out second etching step to remove part dielectric layer 115 with patterning photoresist layer 126, anti-reflecting layer 124, hard mask layer 122 and cap layer 120.Reaction temperature in second etching step is greater than the reaction temperature of first etching step, and temperature difference between the two for example is between 5～20 ℃.Wherein, the reaction temperature of second etching step for example is between 30～50 ℃.On the other hand, in second etching step, for example be to use fluorine-containing hydrocarbon compound, can effectively improve etching selectivity as etching gas.In another embodiment, in first etching step hydrogen atom content of fluorine-containing hydrocarbon compound greater than the hydrogen atom content of hydrocarbon compound fluorine-containing in second etching step.
Above-mentioned second etching step can comprise main etching step and over etching step, and wherein main etching step removes phosphorosilicate glass layer 118 at least, and employed fluorine-containing hydrocarbon compound for example is fluoroform, difluoromethane, also can add as gases such as fluoromethane.In addition, can in reactor body, add according to the characteristic of photoresist as gases such as argon or oxygen.
In main etching step; fluorine-containing hydrocarbon compound can produce reaction with patterning photoresist layer 126; and uniform deposition forms a polymeric layer 130 on patterning photoresist layer 126 surface and sidewall; its material for example is the polymer of short carbon chain; can be in order to protection patterning photoresist layer 126, to improve the hold capacity of patterning photoresist layer 126 in etching process.
On the other hand, in the over etching step, remove non-impurity-doped glassy layer 116, wherein employed fluorine-containing hydrocarbon compound for example is hexafluoro butine, octafluoro pentyne or octafluoro butylene, and gases such as oxygen or argon can be added according to the photoresist characteristic in reacting gas, so that the over etching step can be parked on the etch stop layer 114.
In another embodiment, above-mentioned first etching step, therefore, can carry out in different reaction chambers because the temperature of operation is different with second etching step.
Then, please refer to Fig. 1 F and remove polymeric layer 130, patterning photoresist layer 126 and clearance wall 128, the method that removes for example is the dry-etching method.Then, remove anti-reflecting layer 124, the method that removes for example is the dry-etching method.Next, remove partially-etched stop layer 114, exposing the metal silicide 112 of 110 tops, drain region, and form contact window 132, the method that removes for example is a wet etching, as utilizes hot phosphoric acid method to carry out it.Among another embodiment, remove partially-etched stop layer 114 in, can remove hard mask layer 122 in the lump.So far, finished contact window 132, and other semiconductor technologies such as follow-up formation contact hole or metal interconnecting have in the technical field for this reason and know that usually the knowledgeable institute is known, are not giving unnecessary details in this.
In the above-described embodiments, the engraving method of first etching step and second etching step carries out etching in different reaction temperatures and reacting gas, meaning is promptly adjusted temperature and reacting gas, to reach the critical size that dwindles after the etching, to reduce the consumption of patterning photoresist layer 126 in etching process and prevent that patterning photoresist layer 126 and anti-reflecting layer 124 from the problem of enlargings taking place and improve effect such as etching selectivity.
In sum, have following advantage at least of the present invention:
1. utilize engraving method of the present invention to carry out etching, can obtain the critical size after the less etching, can dwindle critical size to improve the element integrated level with the critical size after the bigger development.
2. engraving method proposed by the invention can form polymer it is protected on patterning photoresist layer, can improve the hold capacity of patterning photoresist layer, produces the problem of enlarging to avoid patterning photoresist layer and anti-reflecting layer.。
3. engraving method proposed by the invention has higher etching selectivity.
4. less according to the critical size of the formed contact window of formation method of contact hole proposed by the invention, can reduce the bridge joint phenomenon of contact hole, to improve the reliability of semiconductor element.
Though the present invention discloses as above with preferred embodiment; yet it is not in order to limit the present invention; those skilled in the art can do a little change and retouching without departing from the spirit and scope of the present invention, thus protection scope of the present invention should with accompanying Claim the person of being defined be as the criterion.
Claims (24)
1, a kind of engraving method is applicable to the semiconductor substrate, has a dielectric layer and an anti-reflecting layer on its surface in regular turn, and this method comprises the following steps:
Form a patterning photoresist layer on this anti-reflecting layer, this patterning photoresist layer exposes this anti-reflecting layer of part;
With this patterning photoresist layer is mask, carries out one first etching step, to remove this anti-reflecting layer that exposes at least; And
As mask, carry out one second etching step with this patterning photoresist layer, to remove this dielectric layer of part, wherein, the temperature of this first etching step is lower than the temperature of this second etching step; And
Remove this patterning photoresist layer.
2, engraving method as claimed in claim 1, wherein the temperature of this first etching step is lower than temperature 5-20 ℃ of this second etching step.
3, engraving method as claimed in claim 1, wherein the temperature range of this first etching step is included between 0 ℃～30 ℃.
4, engraving method as claimed in claim 1, wherein the temperature range of this second etching step is included between 30 ℃～50 ℃.
5, engraving method as claimed in claim 1, wherein this first etching step is included in the different reaction chambers with this second etching step and carries out.
6, engraving method as claimed in claim 1 wherein in the process of carrying out this first etching step, can form a polymer clearance wall on the sidewall of this patterning photoresist layer.
7, a kind of formation method of contact window comprises:
One substrate is provided, in this substrate, has been formed with a conduction region;
In this substrate, form a dielectric layer and cover this conduction region;
On this dielectric layer, form an anti-reflecting layer;
On this anti-reflecting layer, form a patterning photoresist layer;
With this patterning photoresist layer is mask, carries out one first etching step, to remove this anti-reflecting layer that exposes at least; And
As mask, carry out one second etching step to remove this dielectric layer and to expose this conduction region with this patterning photoresist layer and this anti-reflecting layer, wherein, the temperature of this first etching step is lower than the temperature of this second etching step; And
Remove this patterning photoresist layer.
8, the formation method of contact window as claimed in claim 7, wherein the temperature of this first etching step is lower than temperature 5-20 ℃ of this second etching step.
9, the formation method of contact window as claimed in claim 7, wherein the temperature range of this first etching step is included between 0 ℃～30 ℃.
10, the formation method of contact window as claimed in claim 7, wherein the temperature range of this second etching step is included between 30 ℃～50 ℃.
11, the formation method of contact window as claimed in claim 7 also is included in and uses one first fluorine-containing hydrocarbon compound in this first etching step, uses one second fluorine-containing hydrocarbon compound in this second etching step.
12, the formation method of contact window as claimed in claim 11, wherein this first fluorine-containing hydrocarbon compound comprises tetrafluoromethane.
13, the formation method of contact window as claimed in claim 12, in this first etching step, employed etching gas also comprises the mist of octafluoro butylene and hexafluoro butine.
14, the formation method of contact window as claimed in claim 11, wherein this second etching step comprises a main etching step and an over etching step.
15, the formation method of contact window as claimed in claim 14, wherein employed this second fluorine-containing hydrocarbon compound of this main etching step comprises fluoroform, difluoromethane.
16, the formation method of contact window as claimed in claim 15, wherein the employed etching gas of this main etching step also comprises a fluoromethane.
17, the formation method of contact window as claimed in claim 14, wherein employed this second fluorine-containing hydrocarbon compound of this over etching step comprises hexafluoro butine, octafluoro pentyne or octafluoro butylene.
18, the formation method of contact window as claimed in claim 17, wherein the employed etching gas of this over etching step also comprises oxygen or argon.
19, the formation method of contact window as claimed in claim 7, wherein this first etching step carries out in different reaction chambers with this second etching step.
20, the formation method of contact window as claimed in claim 7 is included in the process of carrying out this first etching step, can form a polymer clearance wall on the sidewall of this patterning photoresist layer.
21, the formation method of contact window as claimed in claim 7 also is included in and forms before this dielectric layer formation one metal silicide on this conduction region.
22, the formation method of contact window as claimed in claim 21, wherein the material of this metal silicide comprises nickle silicide, tungsten silicide or cobalt silicide.
23, the formation method of contact window as claimed in claim 7 also is included in before this dielectric layer of formation, forms an etch stop layer in this substrate, and removes this etch stop layer of part after carrying out second etching step.
24, the formation method of contact window as claimed in claim 7 also is included in before this anti-reflecting layer of formation, forms a hard mask layer on this dielectric layer, and removes this hard mask layer of part in this first etching step.
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| CNB2005100794191A CN100468640C (en) | 2005-06-21 | 2005-06-21 | Etching method and contact window forming method |
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| CNB2005100794191A CN100468640C (en) | 2005-06-21 | 2005-06-21 | Etching method and contact window forming method |
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| CN100468640C true CN100468640C (en) | 2009-03-11 |
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