Method for manufacturing semiconductor element and resist pattern cure apparatus

Abstract

To propose a technique capable of suppressing deformation of a resist pattern.SOLUTION: A method for manufacturing a semiconductor element comprises step of: forming a resist pattern composed of a photosensitive resin on a surface of a semiconductor substrate; and irradiating, with light having a wavelength transmitting through the semiconductor substrate, the resist pattern from both an upper side of the resist pattern and a lower side of the semiconductor substrate. When a semiconductor element is manufactured by the manufacturing method, light is applied to the upper surface, the side surfaces, and the lower surface of the resist pattern, so that chemical reactions inside the resist pattern are likely to occur uniformly. Furthermore, by heating the resist pattern, the chemical reactions are promoted. As a result, deformation of the resist pattern can be suppressed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a method for manufacturing a semiconductor device and a resist pattern curing apparatus. [Background technology]

[0002] In the method for manufacturing a semiconductor device described in Patent Document 1, a resist pattern made of a photosensitive resin is formed, and then the resist pattern is irradiated with UV light. The UV irradiation causes the resin that makes up the resist pattern to react and become stabilized. After the UV irradiation step, the semiconductor substrate is dry-etched through the resist pattern. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-86353 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, UV is irradiated onto the resist pattern from above, making it difficult for UV to reach the inside of the resist pattern. Therefore, it is difficult for the resin inside the resist pattern to be exposed to light. For this reason, when heat is subsequently applied to the resist pattern, the resist pattern is likely to deform. This specification proposes a technology for suppressing deformation of the resist pattern. [Means for solving the problem]

[0005] The method for manufacturing a semiconductor element according to aspect 1 disclosed in the present specification includes the steps of forming a resist pattern made of a photosensitive resin on a surface of a semiconductor substrate, and irradiating light having a wavelength that is transmitted through the semiconductor substrate onto the resist pattern from above the resist pattern and from below the semiconductor substrate.

[0006] When a semiconductor device is manufactured using the above manufacturing method, the resist pattern is irradiated with light from both above and below, which makes it easier for chemical reactions to occur uniformly in the resist pattern, thereby suppressing deformation of the resist pattern. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 2] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 3] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 4] 1 is a schematic diagram of a resist pattern curing device according to a first embodiment. [Figure 5] FIG. 2 is a diagram showing the stage of the first embodiment as viewed from above. [Figure 6] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 7] 1 is a method for manufacturing a semiconductor device according to an embodiment. [Figure 8] FIG. 10 is a schematic view of a resist pattern curing device according to a second embodiment.

[0008] Following the above-mentioned first embodiment, additional configurations of the semiconductor device manufacturing method and resist pattern curing apparatus disclosed in this specification will be described below. (Aspect 2) In the step of irradiating light, the light is irradiated from an upper light source provided above the resist pattern, and the light irradiated from the upper light source is reflected toward the resist pattern by a lower reflector provided below the semiconductor substrate. (Aspect 3) In the manufacturing method according to aspect 1, in the step of irradiating the resist pattern with light, the light is irradiated from an upper light source provided above the resist pattern, and the light is irradiated from a lower light source provided below the semiconductor substrate. (Aspect 4) The manufacturing method according to aspect 3, wherein in the step of irradiating light, the semiconductor substrate is placed on a stage, and light irradiated from the lower light source passes through the stage and the semiconductor substrate and impinges on the resist pattern. (Aspect 5) A manufacturing method according to aspect 4, wherein a heat medium flow path is provided inside the stage, and in the step of irradiating with light, the resist pattern is heated by flowing a heat medium through the heat medium flow path. (Aspect 6) A manufacturing method according to any one of aspects 1 to 5, wherein in the step of irradiating light, the light irradiated from the upper light source is reflected toward the resist pattern by an upper reflector provided above the semiconductor substrate. (Aspect 7) The manufacturing method according to any one of aspects 1 to 6, further comprising, after the step of irradiating with light, a step of implanting ions into the semiconductor substrate through the resist pattern, or a step of dry etching the semiconductor substrate through the resist pattern. (Aspect 8) Aspect 8. The method according to any one of Aspects 1 to 7, wherein the step of forming the resist pattern comprises the steps of: forming a resist film from the photosensitive resin; exposing the resist film to light to transfer a pattern to the resist film; and removing exposed or unexposed portions of the resist film. (Aspect 9) A resist pattern curing apparatus comprising: a stage on which a semiconductor substrate having a resist pattern formed on its surface is placed; an upper light source disposed above the stage and irradiating light of a wavelength that is transmitted through the semiconductor substrate; and a lower reflecting member disposed below the stage and reflecting the light irradiated from the upper light source. (Aspect 10) A resist pattern curing apparatus comprising: a stage on which a semiconductor substrate having a resist pattern formed on its surface is placed; an upper light source disposed above the stage and irradiating light of a wavelength that is transmitted through the semiconductor substrate; and a lower light source disposed below the stage and irradiating light of a wavelength that is transmitted through the semiconductor substrate.

[0009] According to the second aspect, the upper light source can irradiate the resist pattern with light from above, and the lower reflector can irradiate the resist pattern with light from below.

[0010] According to the above-mentioned third aspect, the upper light source can irradiate the resist pattern with light from above, and the lower light source can irradiate the resist pattern with light from below.

[0011] According to the sixth aspect, the light reflected by the upper reflector is likely to strike the side surface of the resist pattern.

[0012] According to the seventh aspect, even if the temperature of the resist pattern rises during ion implantation or dry etching, the resist pattern is unlikely to deform.

[0013] Example 1 A description will be given of a method for manufacturing a semiconductor device according to Example 1. In this manufacturing method, a resist pattern forming step, a resist pattern curing step, and an ion implantation step are carried out in this order.

[0014] The resist pattern forming process includes a resist film forming process, an exposure process, and a development process. First, as shown in FIG. 1, in the resist film forming process, a resist layer 12 is formed on a semiconductor substrate 10. The semiconductor substrate 10 is made of a SiC substrate, a SiO2 substrate, or the like. When the semiconductor substrate 10 is a SiC substrate, the semiconductor substrate 10 is transparent to wavelengths of 380 nm to 450 nm. When the semiconductor substrate 10 is a SiO2 substrate, the semiconductor substrate 10 is transparent to wavelengths of 150 nm. The resist layer 12 is made of a photosensitive resin.

[0015] Next, as shown in FIG. 2, in the exposure step, light is selectively irradiated onto the surface of the resist layer 12. The resist layer 12 is altered within the areas irradiated with light. Hereinafter, the portions of the resist layer 12 that are irradiated with light (i.e., the altered portions) will be referred to as exposed portions 14, and the portions that are not irradiated with light will be referred to as unexposed portions 16. As shown in FIG. 2, a pattern of the exposed portions 14 and unexposed portions 16 is formed within the resist layer 12. In other words, the pattern shape is transferred to the resist layer 12.

[0016] Next, in the development process, a developer is applied to the resist layer 12 to form a resist pattern. If the resist layer 12 is a positive type, the exposed portions 14 are removed by the developer. Therefore, as shown in FIG. 3, the remaining unexposed portions 16 form a resist pattern 18. On the other hand, if the resist layer 12 is a negative type, the unexposed portions 16 are removed by the developer, and the remaining exposed portions 14 form a resist pattern 18.

[0017] Next, a resist pattern curing process is carried out using a resist pattern curing apparatus 100 shown in FIG.

[0018] The resist pattern curing apparatus 100 has a stage 20 in a chamber 102. A semiconductor substrate 10 having a resist pattern 18 formed on its surface is placed on the stage 20. The resist pattern curing apparatus 100 irradiates the resist pattern 18 with light to increase the heat resistance of the resist pattern 18.

[0019] As shown in FIG. 5, the stage 20 comes into contact with the edge of the semiconductor substrate 10 at multiple points when viewed from above.

[0020] 4, the resist pattern curing apparatus 100 has an upper light source 30, an upper reflector 40, a lower reflector 42, and a heat treatment table 22. The upper light source 30 is disposed above the stage 20. The upper light source 30 irradiates light with a wavelength that can be transmitted through the semiconductor substrate 10.

[0021] Upper reflector 40 is provided on the inner wall of chamber 102 in the area above stage 20. Upper reflector 40 reflects light irradiated from upper light source 30. Upper reflector 40 is made of a material with a reflectance of 80% or more for light irradiated from upper light source 30. Examples of materials for upper reflector 40 include an aluminum vapor deposition film.

[0022] The lower reflector 42 is disposed below the stage 20. A gap is provided between the lower reflector 42 and the semiconductor substrate 10. The lower reflector 42 reflects the light emitted from the upper light source 30. The lower reflector 42 is made of a material with a reflectance of 80% or more for the light emitted from the upper light source 30. Examples of materials for the lower reflector 42 include an aluminum vapor deposition film.

[0023] The heat treatment table 22 is in contact with the lower surface of the lower reflector 42. The heat treatment table 22 heats the semiconductor substrate 10 and the resist pattern 18.

[0024] In the resist pattern curing process, light is emitted from an upper light source 30, as shown in FIG. 4 . The light emitted from the upper light source 30 toward the semiconductor substrate 10 mainly directly strikes the upper surface of the resist pattern 18. Furthermore, the light emitted from the upper light source 30 toward the upper reflector 40 is reflected by the upper reflector 40 and strikes the upper and side surfaces of the resist pattern 18. Furthermore, a portion of the light emitted from the upper light source 30 is reflected by the lower reflector 42. The light reflected by the lower reflector 42 passes through the semiconductor substrate 10 and strikes the lower surface of the resist pattern 18. In this manner, light is irradiated onto the upper, side, and lower surfaces of the resist pattern 18. Furthermore, in the resist pattern curing process, the resist pattern 18 is heated by a heat treatment table 22. The resist pattern 18 is heated to a temperature equal to or higher than its glass transition temperature.

[0025] In the resist pattern curing process, the resist pattern 18 is irradiated with light, causing a crosslinking reaction in the resist pattern 18. Because the top, side, and bottom surfaces of the resist pattern 18 are exposed to light, the crosslinking reaction occurs throughout the entire resist pattern 18. Furthermore, in the resist pattern curing process, the crosslinking reaction is accelerated by heating the resist pattern 18. The crosslinking reaction hardens the resist pattern 18, improving the heat resistance of the resist pattern 18. Because the crosslinking reaction occurs throughout the entire resist pattern 18, the heat resistance of the resist pattern 18 can be improved efficiently.

[0026] Next, an ion implantation process is performed. In the ion implantation process, ions are implanted into the semiconductor substrate 10 through the resist pattern 18, as shown in FIG. 6. That is, the resist pattern 18 on the semiconductor substrate 10 is used as a mask when implanting ions. Ions are implanted into the semiconductor substrate 10 within the openings of the resist pattern 18, and a diffusion layer 50 is formed.

[0027] In the ion implantation process, the resist pattern 18 is heated by the implantation of ions. Because the heat resistance of the resist pattern 18 is improved in the resist pattern curing process, the resist pattern 18 hardly deforms even when heated in the ion implantation process. Therefore, the diffusion layer 50 can be formed with high precision, and the desired profile can be obtained. Furthermore, because pattern deformation of the resist pattern 18 is suppressed, cracking of the resist pattern 18 can be prevented.

[0028] In the above-described first embodiment, even if the resist pattern 18 is a thick film, the upper surface, side surfaces, and lower surface of the resist pattern 18 are exposed to light, so that the resist pattern 18 can be cured efficiently.

[0029] In the above-described first embodiment, the ion implantation step is performed after the resist pattern curing step, but a dry etching step may also be performed. In the dry etching step, the semiconductor substrate 10 is etched through the resist pattern 18, as shown in FIG. 7. That is, trenches 52 are formed in the semiconductor substrate 10 within the openings of the resist pattern 18.

[0030] In the dry etching process, the resist pattern 18 is heated. Because the heat resistance of the resist pattern 18 is improved in the resist pattern curing process, the resist pattern 18 hardly deforms even when heated in the dry etching process. As a result, the trench 52 can be formed with high precision. Furthermore, because the pattern deformation of the resist pattern 18 is suppressed, cracks in the resist pattern 18 can be prevented.

[0031] Example 2 A method for manufacturing a semiconductor device according to Example 2 will be described. In Example 2, a resist pattern forming step is performed in the same manner as in Example 1. Next, a resist pattern curing step is performed using a resist pattern curing apparatus 200 shown in FIG. 8. In FIG. 8, parts common to those in FIG. 4 are designated by the same reference numerals. As shown in FIG. 8, the resist pattern curing apparatus 200 has a lower light source 32 and a heat treatment stage 24. A semiconductor substrate 10 having a resist pattern 18 formed on its surface is placed on the heat treatment stage 24. The heat treatment stage 24 is made of a material that is transparent to light of wavelengths irradiated by the upper light source 30 and a lower light source 32 (described later). The heat treatment stage 24 can be made of, for example, quartz.

[0032] A heat medium flow path 26 is provided inside the heat treatment stage 24. A heat medium (for example, air) flows through the heat medium flow path 26. The heat medium flowing through the heat medium flow path 26 heats the semiconductor substrate 10 and the resist pattern 18.

[0033] The lower light source 32 is disposed below the heat treatment stage 24. The lower light source 32 irradiates light with a wavelength that can be transmitted through the semiconductor substrate 10 and the heat treatment stage 24.

[0034] In the resist pattern curing process of Example 2, as shown in FIG. 8 , light is emitted from an upper light source 30 and a lower light source 32. The light emitted from the upper light source 30 toward the semiconductor substrate 10 mainly directly hits the upper surface of the resist pattern 18. The light emitted from the upper light source 30 toward the upper reflector 40 is reflected by the upper reflector 40 and hits the upper and side surfaces of the resist pattern 18. The light emitted from the lower light source 32 toward the semiconductor substrate 10 passes through the heat treatment stage 24 and the semiconductor substrate 10 and hits the lower surface of the resist pattern 18. In the resist pattern curing process of Example 2, a heat medium is flowed through the heat medium flow path 26. This heats the semiconductor substrate 10 and the resist pattern 18. The resist pattern 18 is heated to a temperature equal to or higher than the glass transition temperature. The heating temperature of the resist pattern 18 is controlled by the temperature and flow rate of the heat medium flowing through the heat medium flow path 26.

[0035] In the resist pattern curing process, the resist pattern 18 is irradiated with light, causing a crosslinking reaction in the resist pattern 18. In the resist pattern curing process, the top, side, and bottom surfaces of the resist pattern 18 are exposed to light, causing a crosslinking reaction in the entire resist pattern 18. Furthermore, in the resist pattern curing process, the crosslinking reaction is promoted by heating the resist pattern 18. The crosslinking reaction hardens the resist pattern 18, improving the heat resistance of the resist pattern 18. Since the crosslinking reaction occurs in the entire resist pattern 18, the heat resistance of the resist pattern 18 can be improved efficiently.

[0036] Next, an ion implantation step or a dry etching step is performed in the same manner as in Example 1. Because the heat resistance of the resist pattern 18 is improved in the resist pattern curing step, the resist pattern 18 hardly deforms even when heated in the ion implantation step or the dry etching step. Therefore, a semiconductor device can be suitably manufactured.

[0037] In the above-described embodiment, one upper light source 30 and one lower light source 32 are provided, but two or more may be provided.

[0038] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0039] 10: Semiconductor substrate 18: Resist pattern 20: Stage 22: Heat treatment table 24: Heat treatment stage 26: Heat transfer medium flow path 30:Top light source 32: Bottom light source 40: Upper reflective material 42: Lower reflector 100: Resist pattern curing device 102: Chamber 200: Resist pattern curing device

Claims

1. A method for manufacturing a semiconductor device, comprising: A step of forming a resist pattern (18) made of a photosensitive resin on the surface of a semiconductor substrate (10); irradiating the resist pattern from above the resist pattern and from below the semiconductor substrate with light having a wavelength that can be transmitted through the semiconductor substrate; A manufacturing method comprising:

2. 2. The manufacturing method according to claim 1, wherein in the step of irradiating light, the light is irradiated by an upper light source (30) provided above the resist pattern, and the light irradiated from the upper light source is reflected toward the resist pattern by a lower reflector (42) provided below the semiconductor substrate.

3. 2. The manufacturing method according to claim 1, wherein in the step of irradiating light, the light is irradiated by an upper light source (30) provided above the resist pattern, and the light is irradiated by a lower light source (32) provided below the semiconductor substrate.

4. 4. The manufacturing method according to claim 3, wherein in the step of irradiating light, the semiconductor substrate is placed on a stage (24), and light irradiated from the lower light source passes through the stage and the semiconductor substrate and impinges on the resist pattern.

5. A heat transfer medium flow path (26) is provided inside the stage, The manufacturing method according to claim 4 , wherein in the step of irradiating the resist pattern with light, the resist pattern is heated by flowing a heat medium through the heat medium flow path.

6. 4. The manufacturing method according to claim 2, wherein in the step of irradiating light, the light irradiated from the upper light source is reflected toward the resist pattern by an upper reflector (40) provided above the semiconductor substrate.

7. 2. The manufacturing method according to claim 1, further comprising, after the step of irradiating with light, a step of implanting ions into the semiconductor substrate through the resist pattern, or a step of dry etching the semiconductor substrate through the resist pattern.

8. the step of forming the resist pattern forming a resist film (12) using the photosensitive resin; transferring a pattern to the resist film by exposing the resist film; a step of removing the exposed portion (14) or the unexposed portion (16) of the resist film; The method of claim 1 , comprising:

9. A resist pattern curing apparatus, a stage (20) on which a semiconductor substrate having a resist pattern (18) formed on its surface is placed; an upper light source (30) disposed above the stage and configured to irradiate light having a wavelength that is transmitted through the semiconductor substrate; a lower reflecting member (42) provided below the stage and reflecting the light emitted from the upper light source; A resist pattern curing apparatus having the above structure.

10. A resist pattern curing apparatus, a stage (24) on which a semiconductor substrate having a resist pattern (18) formed on its surface is placed; an upper light source (30) disposed above the stage and configured to irradiate light having a wavelength that is transmitted through the semiconductor substrate; a lower light source (32) provided below the stage and irradiating light of a wavelength that is transmitted through the semiconductor substrate; A resist pattern curing apparatus having the above structure.

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