JP2001092152A - Method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor device which is capable of forming patterns of a film to be processed which have a good perpendicular shape. SOLUTION: This method has at least a stage for forming the film 2 to be processed on a processing substrate 3, a stage for forming the resist patterns 1 consisting of negative images of the desired patterns by using a positive type resist 1 on the film 2 to be processed, a stage for putting the resist patterns 1 into a state soluble in a resist developer, a stage for backfilling the level difference portions of the resist patterns 1 by a fluorine system polymer 4, a stage for etching back the fluorine system polymer 4 until the surface of the positive type resist 1 is exposed, a stage for removing the positive type resist 1 by using the resist developer and a stage for subjecting the film 2 to be processed to anisotropic etching with the fluorine system polymer 4 as a mask.

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 device, and more particularly, to a mask pattern of a fluorine-based polymer having a good vertical shape by embedding a fluorine-based polymer and removing the resist after forming a resist pattern. The present invention relates to a method for manufacturing a semiconductor device capable of forming a semiconductor device.

[0002]

2. Description of the Related Art In recent years, due to demands for multifunctional semiconductor devices and one-chip devices, the processing dimensions of semiconductor devices have been miniaturized, and the design rule is already approaching 0.2 μm. Under the circumstances of such fine processing dimensions, the resist pattern has a thickness of 0.1 mm in view of its resolution and pattern collapse.
There is a situation where the thickness must be reduced to 5 μm or less.
Further, the resist film thickness capable of forming a pattern while securing a lithography margin is generally set to an aspect ratio of 3 or less.

However, on the other hand, the film thickness required for a resist as a mask when processing a film to be processed has not changed much from the past, but rather, the need for vertical processing of the film to be processed tends to increase the film thickness. ing. Therefore, in the future, a great difference will appear between the resist film thickness required from the lithography aspect and the resist film thickness required from the processing aspect.

Therefore, as a pattern transfer technique using a thin film resist that solves the above problems, many multilayer resist processes that have already been proposed can be used. Generally, these techniques have been used as a conventional method of forming a resist pattern on a film to be processed having a step of about 0.3 μm. Therefore, the characteristics required for the lower layer resist, which is a coating film, are to flatten the steps of the film to be processed, and the masking property for the film to be processed is almost the same as that of the resist. At present, due to the spread of chemical mechanical polishing (CMP) technology, the step of the film to be processed has become almost negligible from the viewpoint of lithography.

At present, as a characteristic required for the lower layer resist, it is becoming more important to have a high masking property for a film to be processed. This is because, as the pattern becomes finer, the aspect ratio of processing (dry etching) of the lower layer resist in the multilayer process increases, and a good processed shape cannot be obtained.

A fluorine-based polymer has been considered as a lower-layer resist exhibiting good etching resistance to a silicon oxide film or the like. Instead of the conventional photosensitive resist, a pattern is transferred to a fluorine-based polymer having RIE resistance by using a multilayer resist process, and a pattern forming method using this as a mask has already been disclosed in Japanese Patent Application Laid-Open Nos. No. 186069.
In these inventions, the fluorine-based polymer is processed by oxygen RIE using a silylated resist or a silicon oxide film as a mask.

[0007]

Generally, during the etching of these fluorine-based polymers, CF-based gas is generated from the fluorine-based polymer. It is considered that this CF-based gas is easily decomposed in the etching apparatus and generates fluorine (F) radicals. The F radical easily etches the silicon oxide film, which is a mask of the fluorine-based polymer, and lowers the etching selectivity between the silicon oxide film and the fluorine-based polymer.

[0008] The decrease in the etching selectivity results in deterioration of the processed shape of the fluoropolymer to be used as the mask material. It is considered that the deterioration of the shape of the mask material eventually leads to the deterioration of the processed shape of a film to be originally processed such as an interlayer insulating film. Therefore, a method of forming a pattern of a fluoropolymer without using RIE at the time of pattern transfer is desired.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and an object of the present invention is to provide a semiconductor device capable of forming a fluorine-based polymer mask pattern having a good vertical shape. It is to provide a manufacturing method.

It is still another object of the present invention to provide a method of manufacturing a semiconductor device capable of forming a good pattern of a film to be processed having a good vertical shape.

[0011]

In order to achieve the above object, a first feature of the present invention is a step of forming a film to be processed on a processing substrate and a step of using a positive resist on the film to be processed. Forming a resist pattern consisting of a negative image of a desired pattern, making the resist pattern soluble in a resist developer, and backfilling the step portion of the resist pattern with a fluoropolymer. Etching the fluorine-based polymer until the surface of the positive-type resist is exposed, removing the positive-type resist using a resist developer, and using the fluorine-based polymer as a mask. And a step of performing anisotropic etching.

Here, the "film to be processed" is a film that can be patterned by using anisotropic etching, and may be any of an insulating film, a conductor film, and a semiconductor film. The “processed film” is formed on the processing substrate in a wafer state, and an insulator, a conductor,
Different films or layers made of a semiconductor or the like may be interposed. The “positive resist” is a resist that can be dissolved in a resist developer by performing an exposure process and a high-temperature process necessary for pattern formation. Also,
The “desired pattern” means a pattern formed on a film to be processed. The “resist pattern” is a mask pattern formed by a photolithography process using a normal photosensitive resist.

According to the first feature of the present invention, the step portion of the resist pattern is backfilled with a fluorine-based polymer, and the positive resist is removed using a resist developing solution. A mask pattern of a fluoropolymer composed of a desired pattern of a positive image can be formed. By performing anisotropic etching using a fluorine-based polymer mask pattern having excellent anisotropic etching resistance, the mask pattern during etching is not thinned, and the film to be processed can be processed vertically.

In the first aspect of the present invention, the step of bringing the resist pattern into a state in which the resist pattern can be dissolved in a resist developer includes irradiating the resist pattern with light having an exposure amount necessary for forming the resist pattern. Performing a high-temperature treatment necessary for forming a resist pattern. In addition, the step of etching back the fluoropolymer is preferably performed by plasma treatment using oxygen gas. However, it may be performed by wet processing using a solvent. Further, the step of forming a resist pattern composed of a negative image of a desired pattern by using a positive resist on the film to be processed includes a step of forming an organic antireflection film on the film to be processed, Forming a resist pattern consisting of a negative image of a desired pattern using a positive resist on the antireflection film. By forming the organic antireflection film between the resist and the interlayer insulating film, deterioration of the resist pattern shape due to reflection of laser light can be prevented. further,
The step of forming a resist pattern composed of a negative image of a desired pattern using a positive resist on the film to be processed includes a step of forming an inorganic antireflection film on the film to be processed and a step of forming an inorganic antireflection film. Forming a resist pattern composed of a negative image of a desired pattern using a positive resist on the film. Further, the absorption coefficient of the inorganic antireflection film is 0.05 to 0.5.
It is preferable that the thickness is between 3 and 0.2 μm or more. The effect of preventing the deterioration of the resist pattern shape is improved.

A second feature of the present invention is that a step of forming a film to be processed on a processing substrate, a step of forming a resist pattern composed of a negative image of a desired pattern on the film to be processed, Backfilling the stepped portion with a fluoropolymer, and until the resist surface is exposed
Manufacturing a semiconductor device having at least a step of etching back a fluoropolymer, a step of removing a resist using a resist thinner, and a step of performing anisotropic etching on a film to be processed using the fluoropolymer as a mask That is the way.

Here, the resist used as the material of the “resist pattern” may be either a positive type or a negative type. The “resist thinner” can dissolve a resist that is insoluble in a resist developer.

According to a second feature of the present invention, the step portion of the resist pattern is back-filled with a fluoropolymer, and the resist is removed using a resist thinner. A mask pattern of a fluorine-based polymer consisting of a positive image can be formed. By performing anisotropic etching using a fluorine-based polymer mask pattern having excellent anisotropic etching resistance, the mask pattern during etching is not thinned, and the film to be processed can be processed vertically.

Further, by removing the resist by using a resist thinner, it is not necessary to perform an exposure process and a high-temperature process for dissolving the resist pattern in a resist developing solution. it can.

In the second aspect of the present invention, the step of etching back the fluoropolymer is preferably performed by a plasma treatment using oxygen gas. However, it may be performed by wet processing using a solvent. Further, the step of forming a resist pattern composed of a negative image of a desired pattern on the film to be processed includes the steps of forming an organic antireflection film on the film to be processed, and forming a desired pattern on the organic antireflection film. Forming a resist pattern consisting of a negative image of the above pattern. By forming the organic antireflection film between the resist and the interlayer insulating film, deterioration of the resist pattern shape due to reflection of laser light can be prevented. Further, the step of forming a resist pattern composed of a negative image of a desired pattern on the film to be processed, the step of forming an inorganic antireflection film on the film to be processed,
Forming a resist pattern composed of a negative image of a desired pattern on the inorganic antireflection film. Further, it is desirable that the absorption coefficient of the inorganic anti-reflection film is between 0.05 and 0.3 and the film thickness is 0.2 μm or more. The effect of preventing the deterioration of the resist pattern shape is improved.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1A to 1
FIG. 4E is a cross-sectional view showing a necessary step of the method for manufacturing a semiconductor device according to the first embodiment of the present invention. First of the present invention
1 shows a method of manufacturing a semiconductor device according to the first embodiment.
This will be described with reference to FIGS.

(A) First, a film to be processed 2 is formed on a wafer-like processing substrate 3 made of silicon single crystal. The film to be processed has a thickness of 1 μm deposited by the plasma CVD method.
Is an interlayer insulating film 2 made of a silicon oxide film. The film to be processed is a film that can be patterned by using anisotropic etching, and is not limited to the interlayer insulating film 2 and may be a conductor film or a semiconductor film. The film to be processed is formed on the processing substrate 1 in a wafer state, and a different film or layer made of an insulator, a conductor, a semiconductor, or the like is interposed between the processing substrate 1 and the film to be processed. You may.

(B) Next, a coating of the positive resist 1 is formed on the interlayer insulating film 2 to a thickness of 0.5 μm by spin coating. The resist 1 is a chemically amplified resist for KrF excimer laser (wavelength: 248 nm) exposure,
A positive resist that can be dissolved in a resist developer by performing predetermined exposure processing and high-temperature processing is used. The resist 1 is a normal photosensitive resist, and may be a resist used in a normal photolithography process, and is not limited to the above-described resist.

Subsequently, the processing substrate 3 is placed on a hot plate and prebaked to remove the solvent in the resist 1. Subsequently, the processing substrate 3 is placed in a KrF exposure apparatus, and the resist 1 is exposed at a predetermined exposure amount through a mask on which a negative image of a desired pattern is formed. Here, the desired pattern means a pattern formed on the interlayer insulating film 2.

After that, the processing substrate 3 is placed on the hot plate again, and high-temperature processing such as post-exposure bake (PEB) is performed. Subsequently, the resist exposed by immersion in a predetermined resist developer is selectively removed, and FIG.
As shown in FIG. 1A, a resist pattern 1 having a negative image of a desired pattern is formed on an interlayer insulating film 2.

(C) Next, the resist pattern 1 is brought into a state in which it can be dissolved in a developing solution. Specifically, a KrF excimer laser beam is irradiated with light having an exposure amount necessary for pattern formation.
The entire surface of the resist pattern 1 is irradiated. Subsequently, high-temperature treatment such as PEB necessary for pattern formation is performed. In this case, the entire surface of the resist pattern 1 is sufficiently irradiated with light twice as much as the exposure amount necessary for pattern formation.

(D) Next, the step portion of the resist pattern 1 is back-filled with the fluoropolymer 4. In particular,
On the interlayer insulating film 2 on which the resist 1 is formed, a fluorine-based polymer 4 is coated with a solvent CTSOLV180 having a volume ratio of 10%.
A solution dissolved in (trade name: manufactured by Asahi Glass Co., Ltd.) is applied by spin coating. Thereafter, the solvent is removed by heating at 180 ° C. for 5 minutes on a hot plate to form a 1.5 μm-thick fluoropolymer 4 coating film on the flat portion.
At this time, as shown in FIG. 1B, the step portion of the resist 1 is completely backfilled with the fluoropolymer 4 and the surface of the processing substrate 3 is flattened with the fluoropolymer 4.

As the fluoropolymer 4, Cytop CTXS, which is a copolymer of tetrafluoroethylene and a fluoronomomer having a cyclic perfluoroether group, is used.
(Trade name: manufactured by Asahi Glass Co., Ltd.). By using CYTOP CTXS as a solution dissolved in a solvent CTSOLV180 (trade name, manufactured by Asahi Glass Co., Ltd.), the solution can be applied onto the interlayer insulating film 2 by spin coating, and the step portion of the resist 1 can be backfilled. The fluorine-based polymer 4 is not limited to the above-mentioned products, but may be any as long as it can fill back the steps corresponding to the thickness of the resist 1.

(E) Next, the processing substrate 1 is introduced into a downflow type resist carbonizing apparatus, and a gas containing oxygen gas is exposed until the surface of the resist pattern 1 is exposed as shown in FIG. Plasma treatment using
The fluorine-based polymer 4 is etched back. Since the film thickness of the resist pattern 1 is 0.5 μm and the film thickness of the fluoropolymer 4 is 1.5 μm, the film thickness to be etched back is 1.
0 μm. Etching of the fluoropolymer 4 with oxygen gas is generally possible.

Next, the processing substrate 1 is immersed in a resist developing solution to remove the exposed resist 1 as shown in FIG. 1D. The same resist developing solution as that used at the time of forming the pattern of the resist 1 may be used. At this time, the fluorine-based polymer 4 is not dissolved in the resist developer. Thus, a mask pattern composed of a negative image of a desired pattern of the fluoropolymer 4 having a thickness of 0.5 μm is formed.

(G) Finally, using the fluoropolymer 4 as a mask, anisotropic etching such as RIE using a CF-based gas as a reaction gas is performed, and as shown in FIG. A desired pattern of the interlayer insulating film 2 is formed.

According to the first embodiment of the present invention, the step portion of the resist pattern 1 is backfilled with the fluoropolymer 4 and the resist 1 is removed using a resist developing solution, so that the plasma processing is performed. Instead, it is possible to form a mask pattern of the fluoropolymer 4 composed of a positive image of a desired pattern. Using a mask pattern of fluoropolymer 4 having excellent anisotropic etching resistance,
By performing the anisotropic etching, the thinning of the mask pattern during the etching is eliminated, and the pattern of the interlayer insulating film 2 having a good vertical shape can be formed.

In the first embodiment, the etch-back of the fluorine-based polymer 4 may be performed by a wet process using a solvent instead of the plasma process. For example, after applying the fluoropolymer 4, the processing substrate 3 is immersed in a solvent capable of sufficiently controlling the dissolution rate of the fluoropolymer 4 such as diluted CTSOLV180, and the unnecessary portion of the surface fluoropolymer 4 is removed. I do. Thereafter, after the resist 1 is exposed, the resist 1 is rinsed with water or the like to stop the dissolution of the fluoropolymer 4.

(Comparative Example) As a comparative example of the first embodiment, a method of forming a mask pattern of a fluoropolymer by a conventional multilayer resist process will be described with reference to FIG.

(A) First, an interlayer insulating film 5 which is a film to be processed.
2 is formed on the processing substrate, on which the fluoropolymer 54 is uniformly deposited. Subsequently, the fluoropolymer 54
An SOG (Spin On Glass) 55 as an intermediate layer at the time of processing is applied by a spin coating method and subjected to a high temperature treatment to form a coating film of the SOG 55. Further, as shown in FIG. 5A, a photosensitive resist pattern 51 composed of a positive image of a desired pattern is formed on the SOG 55 by using a normal photolithography process.

(B) Next, as shown in FIG. 5 (b), anisotropic etching is performed using the resist pattern 51 as a mask, and the SOG 55 is selectively etched.
As shown in (b), a resist pattern 5 is formed on the SOG 55.
Transfer 1

(C) Next, RIE using a gas containing oxygen gas is performed using the SOG 55 as a mask to selectively remove the fluoropolymer 54 and transfer the pattern of the SOG 55 to the fluoropolymer 54. 5 (c) to 5
(E) is a process sectional view showing the progress of the RIE treatment of the fluoropolymer 54. First, as shown in FIG. 5C, after the RIE process starts, the resist 51 is still in SOG5.
In the state remaining on the surface 5, fluorine (F) radicals generated by RIE etch the SOG 55 from the side. When the RIE process further proceeds and the resist 51 is removed by RIE as shown in FIG. 5D, the etching rate of the SOG 55 increases, and the SOG 5
The width of 5 is getting smaller. Then, the exposed area of the fluoropolymer 54 using the SOG 55 as an etching mask increases. Therefore, as the fluorine-based polymer 54 is etched deeper, the area where the fluorine-based polymer 54 is etched increases, and the cross-sectional shape of the fluorine-based polymer 54 becomes tapered as shown in FIG. Vertical machining becomes difficult. This fluoropolymer 5
4 is used as a mask to process the interlayer insulating film 52.
As in the case of 55, the fluorine-based polymer 54 recedes, the tapered shape is transferred to the interlayer insulating film 52, and a favorable vertical pattern cannot be obtained.

(Second Embodiment) In a second embodiment of the present invention, the case where the resist 4 is removed using a resist thinner instead of a resist developer is shown in FIG.
This will be described with reference to FIG.

(A) First, an interlayer insulating film 2 which is a film to be processed is formed on a processing substrate 3, and a coating film of a positive resist 1 is formed on the interlayer insulating film 2. Subsequently, pre-baking is performed, the resist 1 is exposed at a predetermined exposure amount through a mask on which a negative image of a predetermined pattern is formed, and PEB is performed. Subsequently, the resist pattern is developed with a resist developing solution to form a resist pattern 1 composed of a negative image of a desired pattern as shown in FIG.

(B) Next, without performing the overall exposure and the PEB of the exposure amount necessary for forming the pattern on the resist after the pattern formation performed in the first embodiment, the interlayer on which the resist pattern 1 is formed is formed. A liquid fluorine-based polymer 4 is applied on the insulating film 2 and heated on a hot plate, as shown in FIG.
To form a coating film. Therefore, the resist 1 is not in a state where it can be dissolved in the resist developer.

(C) Next, as shown in FIG. 1C, the fluorine-based polymer 4 is etched back until the surface of the resist 1 is exposed by a plasma treatment using a gas containing oxygen gas as a reactive gas. .

(D) Next, the resist 1 is removed by a resist thinner such as methyl methoxypropionate (MMP), and as shown in FIG. A pattern of the base polymer 4 is formed. The resist thinner can dissolve the resist 1 that has not been dissolved in the resist developer. Although the resist 1 is dissolved by the resist thinner, the fluoropolymer 4 is not dissolved.

(E) Next, the fluorinated polymer 4 is selectively removed by performing RIE using the fluorinated polymer 4 as a mask and a CF-based gas as a reaction gas.
As shown in (e), a desired pattern of the interlayer insulating film 2 is formed.

According to the second embodiment of the present invention, the step portion of the resist pattern 1 is backfilled with the fluorine-based polymer 4 and the resist 1 is removed by using a resist thinner, so that the plasma processing is not performed. Then, a mask pattern of the fluoropolymer 4 composed of a positive image having a desired pattern can be formed. By performing anisotropic etching using a fluorine-based polymer 4 mask pattern having excellent anisotropic etching resistance, the mask pattern during etching is not thinned, and the interlayer insulating film 2 can be processed vertically. .

Further, since the resist 1 is removed by using the resist thinner, the exposure process and the high-temperature process for dissolving the resist pattern 1 in a resist developing solution are not required, so that the semiconductor manufacturing process is reduced. be able to.

In the second embodiment, as in the first embodiment, the etching back of the fluoropolymer 4 may be performed using a solvent instead of the plasma treatment. For example, after coating the fluoropolymer 4, the diluted CTSO
The processing substrate 3 is immersed in a solvent capable of sufficiently controlling the dissolution rate of the fluoropolymer 4 such as LV180, and the unnecessary portion of the surface fluoropolymer 4 is removed. Thereafter, after the resist 1 is exposed, the resist 1 is rinsed with water or the like to stop the dissolution of the fluoropolymer 4.

In the second embodiment, the positive resist 1 is subjected to exposure processing at a predetermined exposure amount and high-temperature processing through a mask on which a negative image of a desired pattern is formed. Although the case where the resist pattern 1 including a negative image of a desired pattern is formed has been described, the present invention is not limited to this. That is, the negative resist 1 is passed through a mask on which a positive image of a desired pattern is formed.
May be subjected to exposure processing and high-temperature processing to form a resist pattern 1 composed of a negative image of a desired pattern. The reason is that once the negative resist 1 has been subjected to the exposure treatment and the high-temperature treatment, it becomes insoluble in the resist developer, but the resist thinner dissolves the insoluble resist 1 Because it can be.

(Third Embodiment) In a third embodiment, an organic anti-reflection film is formed between a resist and an interlayer insulating film, and the organic anti-reflection film is formed by patterning a fluorine-based polymer. The case of processing later will be described with reference to FIG.

(A) First, an interlayer insulating film 2 to be processed is formed on a processing substrate 3, and an organic antireflection film having a thickness of 0.01 to 0.2 μm is formed on the interlayer insulating film 2. A film 6 is formed. Then, a film thickness of 0.5 on the organic anti-reflection film 6 is formed.
A coating film of the positive resist 1 having a thickness of μm is formed by spin coating. Subsequently, pre-baking is performed, the resist 1 is exposed at a predetermined exposure amount through a mask on which a negative image of a predetermined pattern is formed, and PEB is performed. Subsequently, the resist pattern is developed with a resist developing solution to form a resist pattern 1 composed of a negative image of a desired pattern as shown in FIG.
A KrF excimer laser is applied to the entire surface of the resist pattern 1 after development. And PEB
Is performed so that the resist pattern 1 can be dissolved in the developing solution.

(B) Next, a liquid fluorine-based polymer 4 is applied on the organic anti-reflection film 6 on which the resist pattern 1 is formed by a spin coating method and heated on a hot plate. As shown in FIG. 2B, a coating film of the fluoropolymer 4 is formed.

(C) Next, as shown in FIG. 2 (c), the fluorine-based polymer 4 is etched back by plasma treatment using a gas containing oxygen gas as a reaction gas until the surface of the resist is exposed.

(D) Next, the processing substrate 1 is immersed in a resist developer to remove the exposed resist 1. As a result, as shown in FIG. 2D, a mask pattern of a fluorine-based polymer 4 having a thickness of 0.5 μm and a positive image of a desired pattern is formed.

(E) Next, the organic anti-reflection film 6 is selectively removed by performing RIE using a fluorine-containing polymer 4 as a mask and a gas containing oxygen gas as a reaction gas. 3), the mask pattern of the fluoropolymer 4 is transferred to the organic antireflection film 6.

(F) Next, as shown in FIG. 2F, the interlayer insulating film 2 is selectively removed by performing RIE using a fluorine-based polymer 4 as a mask and a CF-based gas as a reaction gas. Thus, a desired pattern of the interlayer insulating film 2 is formed as shown in FIG.

According to the third embodiment of the present invention, the step portion of the resist pattern 1 is back-filled with the fluoropolymer 4 and the resist 1 is removed using a resist developing solution, so that the plasma processing is performed. Instead, it is possible to form a mask pattern of the fluoropolymer 4 composed of a positive image of a desired pattern. Using a mask pattern of fluoropolymer 4 having excellent anisotropic etching resistance,
By performing the anisotropic etching, the thinning of the mask pattern during the etching is eliminated, and the pattern of the interlayer insulating film 2 having a good vertical shape can be formed.

Further, by forming the organic antireflection film 6 between the resist 1 and the interlayer insulating film 2, it is possible to prevent the pattern shape of the resist from being deteriorated due to the reflection of the laser beam.

In the third embodiment, as in the first embodiment, the etching back of the fluoropolymer 4 may be performed using a solvent instead of the plasma treatment. For example, after coating the fluoropolymer 4, the diluted CTSO
The processing substrate 3 is immersed in a solvent capable of sufficiently controlling the dissolution rate of the fluoropolymer 4 such as LV180, and the unnecessary portion of the surface fluoropolymer 4 is removed. Thereafter, after the resist 1 is exposed, the resist 1 is rinsed with water or the like to stop the dissolution of the fluoropolymer 4.

Further, the resist 1 was prepared by using a resist developing solution.
Has been described, but the present invention is not limited to this. That is, as described in the second embodiment, the resist 1 may be removed using a resist thinner. The number of exposure steps and high-temperature processing steps for the resist 1 after pattern formation can be reduced. When a resist thinner is used, either a positive type or a negative type resist may be used. The reason is that once the negative resist is subjected to the exposure treatment and the high-temperature treatment, it becomes insoluble in the resist developer, but the resist thinner can dissolve the insoluble resist. Because.

(Fourth Embodiment) In the fourth embodiment, an inorganic antireflection film is formed between a resist and an interlayer insulating film, and the inorganic antireflection film is formed by patterning a fluoropolymer. A case of processing later will be described.

(A) First, an interlayer insulating film 2 which is a film to be processed is formed on a processing substrate 3, and an inorganic antireflection film having a thickness of 0.5 μm is formed on the interlayer insulating film 2. . And
On the inorganic antireflection film, a coating film of the positive resist 1 having a thickness of 0.5 μm is formed by a spin coating method. Subsequently, pre-baking is performed, the resist 1 is exposed at a predetermined exposure amount through a mask on which a negative image of a predetermined pattern is formed, PEB is performed, and as shown in FIG. Is used to form a resist pattern comprising a negative image of a desired pattern. A KrF excimer laser is applied to the entire resist pattern after the development. Then, PEB is performed to leave the resist pattern in a state in which it can be dissolved in a developing solution.

(B) Next, a liquid fluorine-based polymer 4 is applied on the inorganic anti-reflection film on which the resist pattern 1 is formed by a spin coating method, and heated on a hot plate to obtain a solution shown in FIG. As shown in (b), a coating film of the fluoropolymer 4 is formed.

(C) Next, as shown in FIG. 2C, the fluorine-based polymer 4 is etched back until the surface of the resist is exposed by plasma treatment using a gas containing oxygen gas as a reaction gas.

(D) Next, the processed substrate 1 is immersed in a resist developer to remove the exposed resist 1. As a result, as shown in FIG. 2D, a mask pattern of a fluorine-based polymer 4 having a thickness of 0.5 μm and a positive image of a desired pattern is formed.

(E) Next, the organic antireflection film 6 is selectively removed by performing RIE using a fluorine-based polymer 4 as a mask and a CF-based gas as a reaction gas.
As shown in (e), the mask pattern of the fluoropolymer 4 is transferred to the organic antireflection film 6.

(F) Next, as shown in FIG. 2 (f), the interlayer insulating film 2 is selectively removed by performing RIE using a fluorine-based polymer 4 as a mask and a CF-based gas as a reaction gas. Thus, a desired pattern of the interlayer insulating film 2 is formed as shown in FIG.

The inorganic antireflection film can be processed under the same RIE conditions as the interlayer insulating film, for example, SiOxNy: H
An inorganic antireflection film such as a film is preferable. FIG.
Is data showing the reflectance at the interface between the resist and the inorganic antireflection film, and FIG. 4 is data showing the change in the amount of light absorbed by the resist due to the change in the thickness of the film to be processed. SiOx
By lowering the ratio of hydrogen (H) in the Ny: H film so that the absorption coefficient of the inorganic antireflection film is between 0.05 and 0.3 and the film thickness is 0.2 μm or more, FIG. As shown, the reflectance at the interface between the resist and the inorganic anti-reflection film can be reduced to 0.2 or less. That is, a dimensional change of the resist 1 due to a change in the thickness of the resist 1 and the thickness of the interlayer insulating film 2 transparent to the KrF excimer laser light can be reduced to 2% or less. Also, the ratio of hydrogen (H) in the SiOxNy: H film is reduced so that the absorption coefficient of the inorganic antireflection film is 0.05 to 0.3.
By setting the thickness to 0.2 μm or more, the variation in the amount of light absorbed by the resist can be made 0.1 or less as shown in FIG. That is, the reflectance at the interface between the resist and the anti-reflection film is set to 1% or less, and the anti-reflection film is sufficient to suppress the standing wave shape of the side wall of the resist.

According to the fourth embodiment of the present invention, the step portion of the resist pattern 1 is back-filled with the fluoropolymer 4 and the resist 1 is removed by using a resist developing solution, so that the plasma processing is performed. Instead, it is possible to form a mask pattern of the fluoropolymer 4 composed of a positive image of a desired pattern. Using a mask pattern of fluoropolymer 4 having excellent anisotropic etching resistance,
By performing the anisotropic etching, the thinning of the mask pattern during the etching is eliminated, and the pattern of the interlayer insulating film 2 having a good vertical shape can be formed.

By forming the inorganic anti-reflection film 6 between the resist 1 and the interlayer insulating film 2, it is possible to prevent the pattern shape of the resist from being deteriorated due to the reflection of the laser beam. Further, the absorption coefficient of the inorganic antireflection film is 0.05 to
0.3 and a film thickness of 0.2 μm or more,
The effect of preventing the pattern shape of the resist 1 from deteriorating is improved.

In the fourth embodiment, as in the first embodiment, the etching back of the fluoropolymer 4 may be performed using a solvent instead of the plasma treatment. For example, after coating the fluoropolymer 4, the diluted CTSO
The processing substrate 3 is immersed in a solvent capable of sufficiently controlling the dissolution rate of the fluoropolymer 4 such as LV180, and the unnecessary portion of the surface fluoropolymer 4 is removed. Thereafter, after the resist 1 is exposed, the resist 1 is rinsed with water or the like to stop the dissolution of the fluoropolymer 4.

Further, the resist 1 was prepared by using a resist developing solution.
Has been described, but the present invention is not limited to this. That is, as described in the second embodiment, the resist 1 may be removed using a resist thinner. The number of exposure steps and high-temperature processing steps for the resist 1 after pattern formation can be reduced. When a resist thinner is used, either a positive type or a negative type resist may be used. The reason is that once the negative resist is subjected to the exposure treatment and the high-temperature treatment, it becomes insoluble in the resist developer, but the resist thinner can dissolve the insoluble resist. Because.

[0071]

As described above, according to the present invention, it is possible to provide a method for manufacturing a semiconductor device capable of forming a mask pattern of a fluorine-based polymer having a good vertical shape.

Further, according to the present invention, it is possible to provide a method of manufacturing a semiconductor device capable of forming a good pattern of a film to be processed having a good vertical shape.

[Brief description of the drawings]

FIGS. 1A to 1E are main process cross-sectional views of a method for manufacturing a semiconductor device according to first and second embodiments of the present invention.

FIGS. 2A to 2F are main process cross-sectional views of a method of manufacturing a semiconductor device according to third and fourth embodiments of the present invention.

FIG. 3 is a diagram showing the relationship between the thickness of an anti-reflection film and the reflectance at the interface between the resist and the anti-reflection film with respect to the absorption coefficient.

FIG. 4 is a diagram showing a change in the amount of light absorbed by a resist due to a change in the thickness of a film to be processed.

5 (a) to 5 (e) are cross-sectional views showing main steps of a multilayer resist process according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resist 2 Interlayer insulating film 3 Substrate 4 Fluoropolymer 6 Antireflection film

Claims (5)

[Claims] A step of forming a film to be processed on the processing substrate; a step of forming a resist pattern comprising a negative image of a desired pattern using a positive resist on the film to be processed; A step of making the resist pattern soluble in a resist developer; a step of backfilling the step portion of the resist pattern with a fluoropolymer; and etching back the fluoropolymer until the surface of the resist is exposed. Performing the step of: removing the positive resist using the resist developer; and performing anisotropic etching on the film to be processed using the fluorine-based polymer as a mask. Manufacturing method of a semiconductor device. 2. The step of forming the resist pattern comprising a negative image of a desired pattern by using the positive resist on the film to be processed, comprising: forming an inorganic antireflection film on the film to be processed. Forming a resist pattern comprising a negative image of a desired pattern using the positive resist on the inorganic anti-reflection film. 2. The method for manufacturing a semiconductor device according to claim 1. A step of forming a film to be processed on the processing substrate; a step of forming a resist pattern comprising a negative image of a desired pattern on the film to be processed; Backfilling with a fluoropolymer, etching back the fluoropolymer until the surface of the resist is exposed, removing the resist using a resist thinner, and using the fluoropolymer as a mask, At least a step of performing anisotropic etching on the processed film. 4. The step of forming the resist pattern comprising a negative image of a desired pattern on the film to be processed, comprising: forming an inorganic antireflection film on the film to be processed; 4. The method of manufacturing a semiconductor device according to claim 3, further comprising the step of: forming the resist pattern comprising a negative image of a desired pattern on the antireflection film. 5. The method for manufacturing a semiconductor device according to claim 1, wherein the step of etching back the fluorine-based polymer is performed by plasma processing using oxygen gas.