KR20100042959A - Method for forming pattern of semiconductor device - Google Patents

Abstract

PURPOSE: A method for forming a pattern of a semiconductor device is provided to prevent contamination of a photoresist pattern by forming a thinner adhesive enhancement layer than an anti-reflective layer on a photoresist interface. CONSTITUTION: An adhesive enhancement layer(167) is formed on the upper side of an etching layer of a substrate(161). The photoresist layer is formed on the upper side of the adhesive enhancement layer. A photoresist pattern(169) is formed by performing a lithography process on the photoresist layer. The adhesive enhancement layer is etched using the photoresist pattern as an etching mask until the etching layer is exposed.

Description

Method for forming pattern of semiconductor device

The present invention relates to a method of forming a pattern of a semiconductor device, and more particularly, to a method of preventing the deterioration of a pattern profile during a photolithography process using an EUV light source.

With the rapid spread of information media such as personal portable equipment and personal computers equipped with memory devices, process equipment for manufacturing reliable and highly integrated semiconductor devices with high capacity storage capacity and improved data access operation speed And technology development is urgently required.

In the highly integrated semiconductor device, the smaller the critical dimension of the pattern line width, that is, the smaller the line width of the pattern, increases the information processing speed. Accordingly, there is a growing interest in immersion photolithography processes that are most effective in controlling the critical dimension of the pattern line width in the semiconductor device manufacturing technology. In addition, the exposure source power, the refractive index (n, refractive index) of the anti-reflection film, and the absorption coefficient of the photoresist in order to reduce the substrate reflectance for the exposure apparatus (NA> 1.0) having a high numerical aperture during the immersion lithography process are performed. Research on adjusting k, extinction co-efficient, etc. continues.

On the other hand, while the photoresist pattern obtained by the immersion photolithography process is increased in order to secure an etch mask margin for the multilayer film, the pattern aspect ratio increases as the line width between patterns is reduced to form a highly integrated pattern. It was. As a result, there is a disadvantage that the pattern collapses when used as an etch mask in a subsequent etching process.

Accordingly, in order to improve the problem and to secure a patterning process window such as focus depth (DOF) or exposure latitude (EL), an amorphous carbon layer for an etching barrier is further introduced under the photoresist pattern.

A method of forming a pattern of a semiconductor device in which an amorphous carbon layer is introduced in a conventional ArF immersion lithography process will be described with reference to FIGS. 1A to 1C.

Referring to FIG. 1A, a mask insulating film 15 and an antireflection film 17 having an excellent etching selectivity with respect to the amorphous carbon layer 13 and the amorphous carbon layer are sequentially deposited on the etched layer 11 of the substrate. A photoresist pattern 19 is formed on the upper surface using an ArF immersion lithography process.

At this time, the anti-reflection film 17 is formed to a thickness of 200 ~ 400Å by the spin coating method, and the photoresist pattern 19 is formed to a thickness of 900 ~ 1200Å.

Referring to FIG. 1B, using the photoresist pattern 19 shown in FIG. 1A as an etching mask, the anti-reflection film 17 and the mask insulating film 15 are etched individually or simultaneously to form a mask insulating film pattern 15-1. ) And the antireflection film pattern 17-1 is formed.

Referring to FIG. 1C, the amorphous carbon layer 13 is etched using the first stacked pattern shown in FIG. 1B as an etching mask to form an amorphous carbon layer pattern 13-1 and a mask insulating layer pattern 15-1. To form a second laminated pattern consisting of. Subsequently, the lower etching layer 11 is etched using the amorphous carbon layer pattern 13-1 as an etching mask to form an etching layer pattern (not shown).

However, in the ArF immersion lithography process, since the substrate reflectance with respect to the ArF light source is high due to the reduction of the thickness of the photoresist pattern, a high index fluid medium and an ArF immersion exposure apparatus having a numerical aperture (NA) higher than 1.35 are used together. Even when used, it is difficult to form a line and space pattern with a uniform line width of 30 nm or less.

Accordingly, recently, an immersion lithography process using a short wavelength EUV (extreme ultra violet, 13.4 nm) light source having a lower substrate reflectance than an ArF light source is applied to a semiconductor device mass production process. That is, as shown in FIG. 2, the EUV immersion lithography process has no difference in pattern profile between the case where the antireflection film is applied to the lower portion of the photoresist film due to the low reflectance (a) and when the antireflection film is not applied (b).

On the other hand, EUV lithography process uses i) hexamethyldisilazane (L) under the photoresist film in order to improve the line width roughness (LWR), the adhesion of the photoresist to the substrate and the contamination of the photoresist from the substrate. hexamethyl disilazane (hereinafter referred to as "HMDS") film or ii) hydrophobic antireflection film must be introduced. At this time, i) the HMDS film increases the adhesion of the hydrophobic resist to the hydrophilic substrate. That is, in the case of the silicon substrate to which the HMDS film is applied, and the oxide film (TEOS) or the nitride film (SIN), the contact angle value is increased than when the HMDS film is not applied, but the resist to the substrate is lower than that of the resist or the anti-reflection film. Adhesion is improved (see Fig. 3). ii) The hydrophobic antireflection film effectively prevents the acid generated inside the photoresist from diffusing into the lower mask film or the amine generated from the lower mask insulating film such as silicon nitride film into the photoresist. That is, in the EUV lithography process, an anti-reflection film is formed on a silicon substrate (see FIG. 4 a) or an anti-reflection film is formed on a substrate of titanium nitride (TiN) or silicon oxynitride film (SiON) (see a in FIG. 5). In this case, it is possible to prevent the deterioration of the pattern profile due to the amine as compared with the case where the anti-reflection film is not applied (see b of FIG. 4). In particular, when the anti-reflection film is not applied to the TiN substrate or the SiON substrate, a large amount of footing is caused under the photoresist pattern because the nitrogen (N) component of the substrate reacts with hydrogen of the photoresist to generate an amine ( B of FIG. 5).

On the other hand, as the size of semiconductor devices is gradually miniaturized, in the EUV lithography process requiring a resolution of 30 nm or less, the height of the photoresist pattern used as an etching mask is further lowered, and thus not only the HMSD film and the hydrophobic antireflection film, It is an important task to secure an etching selectivity and an etching margin of the photoresist pattern with respect to the lower etching layer.

An object of the present invention is to provide a pattern forming method that can prevent the pattern profile from being degraded during the EUV photolithography process.

Specifically, in the present invention, an adhesion promotion layer (APL) having a thickness thinner than an antireflection film is introduced at the interface between the substrate and the photoresist during the photolithography process using an EUV light source, thereby increasing the adhesion of the photoresist to the substrate. Another object of the present invention is to provide a method of forming a pattern of a semiconductor device capable of preventing contamination of a photoresist pattern from a lower substrate.

In the present invention

Forming an adhesion promoter layer on the etched layer of the substrate;

Forming a photoresist film on the adhesion promotion layer;

Performing a lithography process on the photoresist film to form a photoresist pattern; And

Using the photoresist pattern as an etching mask provides a method of forming a pattern of a semiconductor device comprising the step of etching the adhesion enhancement layer until the etched layer is exposed.

In the method of the present invention, the method may further include forming an amorphous carbon layer and a mask insulating film on the etched layer before forming the adhesion promoting layer. The mask insulating film is preferably at least one insulating film selected from the group consisting of a silicon nitride film (SiON), an oxide film and a polysilicon layer having an etching selectivity from an amorphous carbon layer.

) 결합을 포함하는 탄화수소 화합물층이라면 특별히 제한하지 않는다. 이때, 상기 탄화수소 화합물은 지방족 화합물, 지방족 고리 화합물 또는 방향족 화합물을 들 수 있으며, 바람직하게는 sp3 결합을 포함하는 시클로프로판(C₃H₆), 헥사데카히드로피렌(C₁₆H₂₆), sp2 결합을 포함하는 에틸렌(C₂H₄), sp 결합을 포함하는 아세틸렌(C₂H₂) 화합물, 또는 sp2 및 sp3 결합을 모두 포함하는 아세나프틸렌(acenaphtylene, C₁₂H₈) 또는 파이렌(pyrene, C₁₆H₁₀)과 같은 탄화수소 화합물을 들 수 있다. In the method of the present invention, the adhesion promoting layer is made of a hydrocarbon compound, sp (· C ≡ C ·), sp 2 (: C = C :) and sp 3 (

The hydrocarbon compound layer containing a bond is not particularly limited. In this case, the hydrocarbon compound may include an aliphatic compound, an aliphatic ring compound or an aromatic compound, preferably cyclopropane (C ₃ H ₆ ), hexadecahydropyrene (C ₁₆ H ₂₆ ), including the sp3 bond, sp2 bond Ethylene (C ₂ H ₄ ), including an acetylene (C ₂ H ₂ ) compound containing a sp bond, or acenaphthylene (acenaphtylene, C ₁₂ H ₈ ) or pyrene containing both sp2 and sp3 bonds And hydrocarbon compounds such as C ₁₆ H ₁₀ ).

The adhesion promotion layer forming step applies a chemical vapor deposition method by depositing by spraying the hydrocarbon compound in the form of gas under a pressure of 1 ~ 10 Torr pressure and 300 ~ 600 ℃ temperature conditions. In addition, after the mask insulating film is formed in the previous step, the in-situ method is used, but since the deposition time is used in addition to the mask insulating film deposition time, no additional deposition equipment or deposition technology is required. Therefore, the TAT manufacturing turn-around-time is not significantly affected, and there is almost no decrease in production rate.

In addition, since the adhesion promotion layer can be formed by a chemical vapor deposition method, it is possible to deposit a thinner thickness than the antireflection film formed by a conventional spin coating method. For example, the adhesion promoting layer is deposited at a thickness of 5 to 20% with respect to the total thickness of the mask insulating film 100. As a result, it is possible to secure a photoresist pattern etching margin used as an etching mask in a subsequent lower layer etching process.

The photoresist film is not particularly limited as long as it is a conventional chemically amplified ArF photoresist, and is formed by applying and baking a chemically amplified ArF photoresist composition containing a polymer composed of methacrylate repeating units.

In this case, in the baking process, an inter-molecular force or an intra-molecular force is generated between the carbon-carbon bond of the adhesion promoting layer and the methacrylate unit inside the photoresist film, thereby promoting adhesion. Chemical bonds are formed on the layer and the surface of the photoresist to improve the adhesion of the photoresist film to the substrate. For example, when the oxide film is formed on the silicon nitride film, which is a mask insulating film, the contact angle decreases. However, forming the adhesion promoting layer thereon increases the contact angle of the substrate to a level substantially similar to that of the photoresist (see FIG. 6). Therefore, the adhesiveness of the photoresist formed by a subsequent process can be improved.

In the method of the present invention, the photoresist pattern is formed by a known EUV lithography process. In this case, since the reaction between the nitrogen component of the lower TiN or SiON film and the hydrogen of the photoresist is blocked by the adhesion promoting layer to prevent amine generation, the footing shape under the photoresist pattern may be prevented.

In the method of the present invention, the process of simultaneously etching the adhesive enhancement layer and the mask insulating film using the photoresist pattern as an etching mask is performed by an etching process using a fluorine-containing etching gas such as CF ₄ or CHF ₃ . The process of etching the amorphous carbon layer is usually performed by an etching process using oxygen, nitrogen and chlorine gas.

As described above, in the EUV lithography process of the present invention, the adhesion enhancement layer having a contact angle similar to that of the photoresist is deposited at a thin thickness at the interface between the photoresist and the substrate by using a chemical vapor deposition method. Adhesion can be secured. Furthermore, the photoresist pattern margin used as an etching mask can be secured when etching the lower mask insulating film or the like by the adhesion promoting layer, and the diffusion of the amine from the lower substrate into the photoresist film can be prevented. The degradation of the profile of the resist pattern can be improved.

As described above, not only can the adhesion between the substrate and the photoresist film be improved by the method of the present invention, but also the diffusion of amine from the substrate into the photoresist film can be prevented, and furthermore, Since it is possible to deposit with a thin deposition thickness by the vapor deposition method, it is possible to ensure the etching margin of the photoresist pattern during the etching process on the lower etching layer.

Hereinafter, with reference to the accompanying drawings 7a to 7d will be described in detail a preferred embodiment of the present invention. In addition, the preferred embodiment of the present invention is for the purpose of illustration, those skilled in the art will be possible to various modifications, changes, replacements and additions through the spirit and scope of the appended claims, such modifications and modifications are described in the following patents It should be regarded as belonging to the claims.

Referring to FIG. 7A, an amorphous carbon layer 163 is formed on the etched layer 161 of the substrate. Referring to FIG. 7B, a mask insulating layer 165, an adhesion promoting layer 167, and an EUV photoresist film (not shown) are sequentially deposited on the amorphous carbon layer 163 of FIG. 7A. At this time, the thickness of the mask insulating film is 100 ~ 600Å.

) 결합을 포함하는 탄화수소 화합물로 형성된 층이라면 특별히 제한하지 않는다. 이때, 상기 탄화수소 화합물은 지방족 화합물, 지방족 고리 화합물 또는 방향족 화합물을 들 수 있으며, 바람직하게는 sp3 결합을 포함하는 시클로프로판(C₃H₆), 헥사데카히드로피렌(C₁₆H₂₆), sp2 결합을 포함하는 에틸렌(C₂H₄), sp 결합을 포함하는 아세틸렌(C₂H₂) 화합물, 또는 sp2 및 sp3 결합을 모두 포함하는 아세나프틸렌(acenaphtylene, C₁₂H₈) 또는 파이렌(pyrene, C₁₆H₁₀)과 같은 탄화수소 화합물을 들 수 있다. In the present invention, the adhesion promotion layer 167 is made of a hydrocarbon compound, sp (· C≡C ·), sp2 (: C = C :) and sp3 (

The layer is not particularly limited as long as it is a layer formed of a hydrocarbon compound containing a bond. In this case, the hydrocarbon compound may include an aliphatic compound, an aliphatic ring compound or an aromatic compound, preferably cyclopropane (C ₃ H ₆ ), hexadecahydropyrene (C ₁₆ H ₂₆ ), including the sp3 bond, sp2 bond Ethylene (C ₂ H ₄ ), including an acetylene (C ₂ H ₂ ) compound containing a sp bond, or acenaphthylene (acenaphtylene, C ₁₂ H ₈ ) or pyrene containing both sp2 and sp3 bonds And hydrocarbon compounds such as C ₁₆ H ₁₀ ).

In this case, the adhesion promotion layer forming step is carried out by applying a chemical vapor deposition method by depositing by spraying the hydrocarbon compound in the form of gas under a temperature of 1 ~ 10 Torr pressure and 300 ~ 600 ℃ temperature conditions. In this case, the forming of the adhesion promotion layer may be performed by an in-situ method after forming the mask insulating film in the previous step. As such, the adhesion promoting layer may be formed by chemical vapor deposition, and thus may be deposited to a thickness thinner than an antireflection film formed by a conventional spin coating method. For example, the adhesion promoting layer is deposited at a thickness of 5 to 20%, preferably at a thickness of 30 kPa or less, with respect to the total thickness of the mask insulating film 100. As a result, it is possible to secure a photoresist pattern etching margin used as an etching mask in a subsequent lower layer etching process.

The photoresist film (not shown) is a conventional chemically amplified ArF photoresist, which is coated with a chemically amplified ArF photoresist composition containing a polymer composed of methacrylate repeating units, and baked to form a thickness of about 600 to 800 kPa. do.

In this case, a chemical crosslink is formed between the carbon-carbon bond of the adhesion promotion layer 167 and the methacrylate unit inside the photoresist film (not shown) by the baking process, thereby forming a photo for the substrate. The adhesion of the resist film is improved.

Subsequently, a known EUV lithography process is performed on the photoresist film (not shown) to form a photoresist pattern 169.

In this case, in the short wavelength EUV lithography process, since the wavelength is much shorter than that of the ArF light source and the substrate reflectance is low, a photoresist pattern having a uniform pattern profile can be obtained.

Referring to FIG. 7C, by using the photoresist pattern 169 illustrated in FIG. 7B as an etching mask, the adhesion promotion layer 167 and the mask insulating layer 165 are etched together to form a mask insulating layer pattern 165-1. And a first laminate pattern composed of the adhesion promoting layer pattern 167-1.

In this case, since the thickness of the adhesion promotion layer 167 is thinner than the conventional antireflection film thickness by chemical vapor deposition, the etching margin of the photoresist pattern 167 may be secured. In the method of the present invention, since the photoresist pattern is partially removed during the etching process, an additional removal process is not required.

The process of etching the adhesion enhancement layer and the mask insulating layer using the photoresist pattern as an etching mask is performed by an etching process using a fluorine-containing etching gas such as CF ₄ or CHF ₃ .

Referring to FIG. 7D, by using the first stacked pattern of 7c as an etching mask, the amorphous carbon layer 163 is etched until the etched layer 161 is exposed, and then the adhesion promoting layer pattern 167-1. Is removed to form a second stacked pattern including the amorphous carbon layer pattern 163-1 and the mask insulating film pattern 165-1.

The process of etching the amorphous carbon layer 163 is performed by an etching process using a conventional oxygen, nitrogen and chlorine etching gas.

Subsequently, the lower etching layer 161 is etched using the second stacked pattern as an etching mask to form an etching layer pattern (not shown).

1A to 1C are process schematic diagrams showing a method for forming a pattern of a conventional semiconductor device.

2 is a SEM photograph showing a photoresist pattern obtained by a conventional EUV lithography process.

3 is a graph showing the contact angle for each substrate.

Figure 4 is a SEM photograph of the pattern showing the deterioration of the pattern profile according to whether the anti-reflection film applied in the EUV lithography process using a silicon substrate.

FIG. 5 is a SEM photograph of a pattern showing deterioration of a pattern profile depending on whether an antireflection film is applied in an EUV lithography process using a TiN substrate. FIG.

6 is a graph showing a change in the contact angle of the substrate when applying the adhesion promoting layer of the present invention.

7A to 7D are process schematic diagrams illustrating a method for forming a pattern of a semiconductor device of the present invention.

<Brief description of the main parts of the drawing>

11, 161: etching target layer 13, 163: amorphous carbon layer

13-1 and 163-1: amorphous carbon layer patterns 15 and 165: mask insulating film

15-1 and 165-1: mask insulating film pattern 17: antireflection film

17-1: antireflection film patterns 19, 169: photoresist pattern

167: adhesion promoter layer 167-1: adhesion promoter layer pattern

Claims (13)

Forming an adhesion promoter layer on the etched layer of the substrate; Forming a photoresist film on the adhesion promotion layer; Performing a lithography process on the photoresist film to form a photoresist pattern; And Etching the adhesion enhancement layer using the photoresist pattern as an etching mask until the etching target layer is exposed. The method according to claim 1, And forming an amorphous carbon layer and a mask insulating film on the etched layer before forming the adhesion promoting layer. The method according to claim 2, And the mask insulating film is at least one selected from the group consisting of a nitride film, an oxide film and a polysilicon layer. The method according to claim 1, The adhesion promotion layer is a pattern forming method of a semiconductor device, characterized in that consisting of a hydrocarbon compound. The method according to claim 4, The hydrocarbon compound is sp (· C≡C ·), sp2 (: C = C :) and sp3 (

A method for forming a pattern of a semiconductor device, characterized in that the compound comprises at least one bond. The method according to claim 5, The hydrocarbon compound is a pattern forming method of a semiconductor device, characterized in that any one selected from the group consisting of aliphatic compounds, aliphatic ring compounds and aromatic compounds. The method according to claim 5, The hydrocarbon compound is cyclopropane (C ₃ H ₆ ), hexadecahydropyrene (C ₁₆ H ₂₆ ), ethylene (C ₂ H ₄ ), acetylene (C ₂ H ₂ ) compound, acenaphthylene (C ₁₂ H ₈ ) And pyrene (C ₁₆ H ₁₀ ). The method according to claim 1, Forming the adhesion promotion layer is a pattern formation method of a semiconductor device, characterized in that performed by chemical vapor deposition. The method according to claim 1 or 2, The adhesion promotion layer is a pattern forming method of a semiconductor device, characterized in that formed after the mask insulating film (in-situ) method. The method according to claim 1, And the adhesion promoting layer is deposited at a thickness of 5 to 20% with respect to a total thickness of the mask insulating film 100. The method according to claim 1, And the photoresist film is formed by applying and baking a chemically amplified ArF photoresist composition containing a polymer composed of methacrylate repeating units. The method according to claim 1, And the photoresist pattern is formed by an EUV lithography process. The method according to claim 1, The adhesion enhancement layer etching step is a pattern forming method of a semiconductor device, characterized in that performed by the etching process method using a fluorine-containing etching gas.

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