JP2002207300A - Method of manufactured semiconductor and semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve etching resistance by increasing a resist film thickness in a lithography process step. SOLUTION: The chemical amplification type resist is applied on a wafer substrate 11 to form a first resist layer 12 (S1) and thereafter the exposure of the resist patterns is performed (S2). Material which contains an acid propagating agent and induces a decomposition reaction or crosslinking reaction by an acid is applied onto the exposed first resist layer 12 to form a second resist layer (S3) and is subjected to PEB treatment (S4), following which the resist layer is subjected to development by an aqueous alkaline solution (S5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor, and more particularly to a method for manufacturing a semiconductor for forming a resist pattern on a wafer substrate.

[0002]

2. Description of the Related Art In recent years, miniaturization of circuit patterns has been promoted for the purpose of improving the degree of integration and functions of LSIs, and there is a strong demand for forming finer patterns while ensuring a process margin. .

At present, in a lithography process, which is a process of forming a fine pattern in semiconductor manufacturing, an exposure apparatus using a KrF excimer laser having a wavelength of 248 nm as a light source is mainly used. Can be applied up to a resolution of about 0.13 μm. However, in these semiconductor devices, the formation of a gate pattern of 0.11 μm, which is equal to or less than half the exposure wavelength, and the formation of a fine contact hole of 0.15 μm are required.

As a method of expanding a process margin for forming a fine pattern, it is generally known to reduce a resist film thickness. However, if the thickness of the resist film is excessively reduced, the original function of the resist film as a mask cannot be satisfied. Therefore, the resist film thickness must be set in consideration of the etching resistance of the resist film in the etching step after the lithography step.

As a method for obtaining the effect of reducing the thickness of the resist film while maintaining the etching resistance of the resist film, a multi-layer resist method such as a three-layer resist method, a two-layer resist method, or a silylated two-layer resist method has been developed.

The multilayer resist method is a pattern forming method in which after forming a plurality of resist layers, the uppermost layer is exposed to light in a lithography step of the process, and the pattern of the uppermost layer is transferred to a lower resist layer in an etching step. .

In the three-layer resist method, when forming a three-layer resist, it is necessary to form an intermediate layer such as SiO _{2 having} oxygen plasma resistance in order to obtain etching resistance to the lower layer resist. In addition, since the dry etching step for processing the lower layer film is performed twice, there is a problem that the process is complicated and the number of steps is large.

In the two-layer resist method, a silicon-containing resist which is resistant to oxygen plasma is used for an upper layer film. Generally, when silicon is contained in a resin constituting a resist, it affects basic characteristics of the resist such as solubility in a solvent, sensitivity, pattern resolution, and the like, and also has a problem in resist peeling after etching. Further, since dry etching is performed once for processing the lower layer film, the number of steps is increased as compared with a single-layer resist.

The silylation two-layer resist method is a method in which after forming an upper layer pattern, the upper layer is subjected to a silylation treatment to increase the etching resistance to the lower layer resist. The problem with this method is that, compared to a single-layer resist, the number of steps of silylation of the upper layer film and the number of steps of etching the lower layer film increase. Further, problems remain in the pattern controllability and resist stripping due to silylation.

[0010]

As another method for obtaining an effect of reducing the thickness of a resist film while maintaining the etching resistance of the resist film, a lithography process in a semiconductor manufacturing process uses a resist pattern formed on a substrate surface as a single layer. There is a pattern forming method in which a material that causes a decomposition reaction or a cross-linking reaction by an acid is applied to the resist after the exposure treatment, and then a PEB treatment is performed to increase the resist film thickness and improve the etching resistance.

In general, a chemically amplified resist is a mixture of a resin, an acid generator, and a solvent. An acid is generated in the resist by exposure, and the generation of the acid is accelerated by PEB treatment. It reacts with the material that causes a decomposition reaction or a crosslinking reaction by the acid.

According to the above-described pattern forming method, the resist film thickness is increased after the resist pattern is exposed in the lithography step of the semiconductor manufacturing process without complicating the lithography step and increasing the number of etching steps. Thus, the etching resistance can be improved.

However, the above-mentioned method has a problem that the reaction efficiency is poor because a material which causes a decomposition reaction or a cross-linking reaction by an acid can only react with an acid generated on the resist surface.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a method of manufacturing a semiconductor in which etching resistance is improved by a simple method.

[0015]

According to the present invention, in a method of manufacturing a semiconductor, a resist is applied on a wafer substrate, a positive resist is exposed, and a positive resist layer is formed. Manufacturing a semiconductor, characterized in that a resist film is formed by applying a material which contains an acid multiplying agent, causes a decomposition reaction by an acid, and becomes alkali-soluble on the mold resist layer, and then performs a PEB treatment. A method is provided.

According to the above construction, after the exposure treatment of the positive resist, a material containing an acid multiplying agent, which is decomposed by an acid and becomes alkali-soluble by being applied on the positive resist layer, is then subjected to PEB. When processing is performed, the upper layer of the exposed portion of the resist changes to alkali-soluble due to a decomposition reaction by an acid, and the upper layer of the unexposed portion of the resist remains alkali-insoluble, so that the resist film thickness increases and the etching resistance increases. improves.

Further, the material which causes a decomposition reaction by an acid and becomes alkali-soluble contains an acid multiplying agent, so that the decomposition reaction is promoted, the resist film thickness is efficiently increased, and the etching resistance is improved. improves.

In the method of manufacturing a semiconductor device, a resist is applied on a wafer substrate, a negative resist is exposed to light to form a negative resist layer, and an acid multiplying agent is formed on the negative resist layer. After applying a material containing an acid and causing a crosslinking reaction by an acid to become alkali-insoluble,
There is provided a method for manufacturing a semiconductor, comprising performing an EB process to form a resist film.

According to the above construction, after the exposure treatment of the negative resist, a material containing an acid multiplying agent and causing a cross-linking reaction by an acid to become alkali-insoluble is applied on the negative resist layer, and then subjected to PEB treatment. The upper layer of the unexposed portion of the resist remains alkali-soluble, and the upper layer of the exposed portion of the resist changes to alkali-insoluble by a crosslinking reaction with an acid. The film thickness is increased, and the etching resistance is improved.

Further, since a material which becomes insoluble in alkali by causing a cross-linking reaction by an acid contains an acid multiplying agent, the cross-linking reaction is promoted, the resist film thickness is efficiently increased, and etching resistance is improved. I do.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart of a method for forming a resist pattern according to an embodiment of the present invention.

After a chemically amplified resist is applied on a wafer substrate to form a first resist layer (S1), a mask pattern is exposed (S2). Then, the exposed first
On the resist layer, a material containing an acid proliferating agent and causing a decomposition reaction or a cross-linking reaction by an acid is applied to form a second resist layer (S3), subjected to PEB treatment (S4), and then treated with an alkaline aqueous solution. Development is performed (S5). In the case of a positive resist, a portion irradiated with light is removed by exposure, and in the case of a negative resist, a portion not irradiated with light is removed by exposure, so that a resist pattern is formed on a wafer substrate.

Next, the embodiment of the present invention will be described by taking as an example a case where the present invention is applied to a positive resist. 2A and 2B are diagrams schematically showing pattern formation when a positive resist is used. FIG. 2A shows a step of forming a first resist layer, and FIG. 2B shows PEB after forming a second resist layer. FIG. 2 (c) is a decomposition reaction step involving an acid multiplying agent,
FIG. 2D is a view showing a developing step.

In the step of FIG. 2A, the wafer substrate 11
After a positive resist is applied thereon to form the first resist layer 12, the resist pattern is exposed. In the exposed portion irradiated with light, the acid (proton) 13 is generated by irradiating the acid generator with light.

In the step of FIG. 2B, a material containing an acid multiplying agent 14 and causing a decomposition reaction by an acid to become alkali-soluble is applied on the exposed first resist layer 12,
After forming the second resist layer 15, a PEB process is performed.
Thereby, the exposed portion of the first resist layer 12 and the second
In the resist layer 15, a decomposition reaction by the acid 13 occurs and becomes alkali-soluble.

In the step shown in FIG. 2C, the acid 13 diffused from the first resist layer 12 reacts with the acid multiplying agent 14 particularly in the second resist layer 15, so that the acid 13 is newly generated. The decomposition reaction proceeds.

In the step of FIG. 2D, development with an aqueous alkaline solution is performed. By the development, the exposed portions of the first resist layer 12 and the second resist layer 15 are removed, and a pattern is formed by the unexposed portions of the first resist layer 12 and the second resist layer 15.

As a material which is decomposed by an acid and becomes alkali-soluble, a material obtained by adding a dissolution inhibitor which inhibits the solubility of the resin in an aqueous alkali solution to an alkali-soluble resin can be considered. For example, a material obtained by adding an acetal compound as a dissolution inhibitor to a novolak resin, a material obtained by adding a t-butoxycarbonylated compound as a dissolution inhibitor to a novolak resin or polyhydroxystyrene, and the like.

As the acid proliferating agent to be added thereto, there is a cross-linked carbocyclic compound having a hydroxyl group and a sulfonate group. More specifically, the compound has a cross-linked carbocyclic skeleton, and a hydroxyl group and the hydroxyl group are bonded to the cross-linked carbon ring. A cross-linked carbocyclic compound having a sulfonate group at a carbon atom adjacent to the carbon atom in question is considered.

Next, the embodiment of the present invention will be described by taking as an example a case where the present invention is applied to a negative resist. 3A and 3B are diagrams schematically showing pattern formation when a negative resist is used. FIG. 3A shows a step of forming a first resist layer, and FIG. 3B shows a step of forming a PEB after forming a second resist layer. FIG. 3 (c) is a cross-linking reaction step involving an acid multiplying agent,
FIG. 3D is a view showing a developing step.

In the step of FIG. 3A, the wafer substrate 21
After applying a negative resist thereon to form the first resist layer 22, the resist pattern is exposed. In the exposed portion irradiated with the light, the acid (proton) 23 is generated by irradiating the acid generator with the light.

In the step of FIG. 3B, a material containing an acid multiplying agent 24 and causing a crosslinking reaction by an acid to become alkali-insoluble is applied on the exposed first resist layer 22,
After forming the second resist layer 25, a PEB process is performed.
Thus, the exposed portion of the first resist layer 22 and the second
In the resist layer 25, a crosslinking reaction by the acid 23 occurs, and the resist layer 25 becomes insoluble in alkali.

In the step of FIG. 3C, the acid 23 diffused from the first resist layer 22 reacts with the acid multiplying agent 24, particularly in the second resist layer 25, so that the acid 23 is newly generated. The crosslinking reaction proceeds.

In the step of FIG. 3D, development with an aqueous alkaline solution is performed. The unexposed portions of the first resist layer 22 and the second resist layer 25 are removed by development, and a pattern is formed by the exposed portions of the first resist layer 22 and the second resist layer 25.

As a material which causes a crosslinking reaction by an acid and becomes insoluble in alkali, a material obtained by adding a crosslinking agent to an alkali-soluble resin is considered. For example, a material obtained by adding a melamine compound as a cross-linking agent to a novolak resin or polyvinylphenol is used.

As the acid proliferating agent to be added thereto, there is a cross-linked carbocyclic compound having a hydroxyl group and a sulfonate group. More specifically, the compound has a cross-linked carbocyclic skeleton, and the hydroxyl group and the hydroxyl group are bonded to the cross-linked carbon ring. A cross-linked carbocyclic compound having a sulfonate group at a carbon atom adjacent to the carbon atom in question is considered.

In the above description, photolithography is taken as an example, but the present invention can be applied to other techniques for patterning using a chemically amplified resist.

[0038]

As described above, in the present invention, after the exposure treatment of the positive resist, a material which contains an acid multiplying agent and undergoes a decomposition reaction by an acid to become alkali-soluble is used for the positive resist layer. Since the PEB treatment is performed after the application on the upper surface, the film thickness can be efficiently increased to improve the etching resistance, and a process margin for forming a finer pattern can be secured by a simple method.

After the exposure of the negative resist, a material containing an acid multiplying agent and causing a crosslinking reaction by an acid to become alkali-insoluble is applied onto the negative resist layer, and then subjected to PEB treatment. Therefore, the film thickness can be efficiently increased to improve the etching resistance, and a process margin for forming a finer pattern can be secured by a simple method.

[Brief description of the drawings]

FIG. 1 is a flowchart of a method for forming a resist pattern according to an embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a pattern forming method when a positive resist is used.

FIG. 3 is a diagram schematically illustrating a pattern forming method when a negative resist is used.

[Explanation of symbols]

11, 21 ... wafer substrate, 12, 22 ... first resist layer, 13, 23 ... acid, 14, 24 ... acid multiplying agent,
15, 25 ... second resist layer

Claims (13)

[Claims] In a manufacturing method of semiconductor manufacturing, a resist is applied onto a wafer substrate, and a positive resist is exposed to light to form a positive resist layer, and acid multiplication is performed on the positive resist layer. A method for producing a semiconductor, comprising applying a material containing an agent, which is decomposed by an acid to cause a decomposition reaction to become alkali-soluble, and subjecting the material to PEB (Post Exposure Bake) treatment to form a resist film. 2. The method according to claim 1, wherein the acid proliferating agent is a cross-linked carbocyclic compound having a hydroxyl group and a sulfonate group. 3. The method according to claim 1, wherein the material is a material obtained by adding a dissolution inhibitor to an alkali-soluble resin. 4. The material according to claim 1, wherein the material is a material obtained by adding an acetal compound to a novolak resin.
The manufacturing method of the semiconductor of the description. 5. The method according to claim 1, wherein the material is a material obtained by adding a compound obtained by adding t-butoxycarbonyl compound to a novolak resin. 6. The method according to claim 1, wherein the material is polyhydroxystyrene.
The method for producing a semiconductor according to claim 1, wherein the material is a material to which a butoxycarbonylated compound is added. 7. A semiconductor manufactured by the method according to claim 1. 8. A method of manufacturing a semiconductor device, comprising applying a resist on a wafer substrate, performing exposure processing of a negative resist to form a negative resist layer, and applying acid multiplication on the negative resist layer. A method for producing a semiconductor, comprising applying a material containing an agent and causing a cross-linking reaction by an acid to become insoluble in alkali, performing PEB treatment, and forming a resist film. 9. The method according to claim 8, wherein the acid proliferating agent is a cross-linked carbocyclic compound having a hydroxyl group and a sulfonate group. 10. The method according to claim 8, wherein the material is a material obtained by adding a crosslinking agent to an alkali-soluble resin. 11. The material according to claim 8, wherein the material is a material obtained by adding a melamine compound to a novolak resin.
The manufacturing method of the semiconductor of the description. 12. The method according to claim 8, wherein the material is a material obtained by adding a melamine compound to polyvinyl phenol. 13. A semiconductor manufactured by the method according to claim 8.