JP3055774B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of semiconductor devices. More specifically, the present invention uses a coating antireflection film made of a photosensitive material, and uses light exposure on a semiconductor substrate. The present invention relates to a method for manufacturing a semiconductor device in which the antireflection film is selectively formed.

[0002]

2. Description of the Related Art In the patterning of a photoresist (resist) by light exposure, there is a problem that a resist pattern is eroded (notched) by light reflected from a step portion of a substrate and a resist pattern dimension is changed due to a change in resist film thickness. was there.

In order to solve this problem, a method has been proposed in which an antireflection film for preventing reflection of exposure light is formed immediately below a resist to reduce light reflected from a substrate. The antireflection film includes an organic film formed by applying a spin coat on a film to be processed like a resist, and a chemical vapor deposition (CV)
D: Chemical Vapor Depositi
on)). These have the following features, respectively.

In the case of an inorganic antireflection film, it is formed to be thin and to have a constant film thickness irrespective of the height of a step on a film to be processed. As a result, the time required for the dry etching can be shortened, but the dimensional change of the pattern due to the change in the resist film thickness caused by the step occurs.

On the other hand, the organic antireflection film can be formed by coating similarly to the resist, and has a tendency to flatten the step of the substrate. Therefore, by using the organic antireflection film, the resist film thickness can be made substantially constant regardless of the step. As a result, it is also possible to suppress a change in pattern dimension due to a change in the resist film thickness. In addition, since it is a coating film, there is an advantage that formation of an antireflection film is very easy.

As an example of such a coatable antireflection film,
Monthly Semiconductor World June 1995 p10
Examples described in 0-102 are known. This example is shown in FIG.
This will be described with reference to FIG.

[0007] As shown in FIG.
After the film to be processed 52 is formed thereon, the coating antireflection film 53 is formed.
And a resist film 54 is formed on the antireflection film 53.
Is applied and formed.

Thereafter, the resist film 54 is selectively exposed and developed by an exposure device using an i-line or a KrF excimer laser as a light source, and is developed to form a resist pattern 54a as shown in FIG.

Next, as shown in FIG. 5C, the antireflection film 53 is dry-etched using the resist pattern 54a as a mask to form an antireflection film pattern 53a.

Using the resist pattern 54a and the antireflection film pattern 53a as a mask, the film to be processed 52 is etched, and as shown in FIG.
2a is formed.

Then, the resist pattern 54a and the anti-reflection film pattern 53a are removed to obtain the structure shown in FIG.
As shown in (e), a desired processed film pattern 52a can be obtained.

[0012]

As described above, the coatable anti-reflection film is very easy to form, and prevents the exposure light from being reflected from the substrate to form a resist pattern having no dimensional change. Become.

However, on an actual semiconductor substrate,
There are local steps. Due to the presence of this local step, the thickness of the antireflection film partially increases, and the etching time of the antireflection film increases. As a result, the resist remaining film necessary for dry-etching the film to be processed is partially lost, and the resist film and the anti-reflection film pattern are lost during the etching of the film to be processed, and the deformation of the film pattern to be processed is thereby caused. And loss.

The above problems will be described with reference to the drawings while following the flow of a conventional method for manufacturing a semiconductor device.

As shown in FIG. 6A, the semiconductor substrate 61
A film to be processed 62 is formed thereon, and then an anti-reflection film 63,
A resist film 64 is applied and formed in order.

The resist film 64 is selectively exposed and developed by an exposure device using an i-line or a KrF excimer laser as a light source, developed, and a resist pattern 64a as shown in FIG.
To form

Next, as shown in FIG. 6C, the antireflection film 63 is dry-etched using the resist pattern 54a as a mask to form an antireflection film pattern 63a. At this time, the antireflection film is also formed on a local step (recess) 65 where no device pattern exists. Since the thickness of the antireflection film 63 is larger in the local step 65 than in other portions, the time required for etching the antireflection film increases. As a result, in the region other than the local step 65, the anti-reflection film etching process is performed for an unnecessarily long time, and a necessary resist remaining film is lost during this etching process.

When the film 62 to be processed is etched in this state, the film pattern 62a to be processed is deformed or lost as shown in FIG. 6D.

[0019]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to form a proper film pattern to be processed by leaving a resist pattern and an antireflection film pattern having a thickness and a shape necessary for etching the film to be processed. It is an object of the present invention to provide a possible method for manufacturing a semiconductor device.

[0020]

According to the present invention, in order to achieve the above object, an antireflection film and a photoresist film are sequentially formed on a film to be processed. Forming a pattern of a photoresist film and an antireflection film by patterning an anti-reflection film, and etching the film to be processed using the pattern as a mask;
Using a material composed of a photosensitive material as the material of the anti-reflection film, selectively forming the anti-reflection film on the film to be processed using light exposure, and forming the photoresist film thereon And a method for manufacturing a semiconductor device.

In one embodiment of the present invention, the antireflection film is selectively formed only on a region where a device pattern exists.

In one embodiment of the present invention, the antireflection film is selectively formed only in a region where the patterning is fine and the design rules of the semiconductor device are strict.

In one embodiment of the present invention, the antireflection film is selectively formed only on a region other than a region having a large local step formed on the film to be processed.

In one embodiment of the present invention, the local step formed on the film to be processed reflects the shape of the surface of the semiconductor substrate on which the film to be processed is formed.

In one embodiment of the present invention, the material of the anti-reflection film is formed of a photosensitive material which is cross-linked by light exposure and which forms an anti-reflection film selectively in the exposed region by development. Use what is done.

In one embodiment of the present invention, the material of the antireflection film is solubilized in a developing solution by light exposure, and the antireflection film is selectively formed in a region other than the exposed region by development. A material made of a suitable photosensitive material is used.

As described above, in the present invention, by forming the antireflection film from a photosensitive material, the antireflection film can be selectively formed on the film to be processed on the semiconductor substrate. This makes it possible to selectively form the anti-reflection film so as to avoid an area having a large local step, thereby preventing an extremely thick anti-reflection film from being formed at the step. As a result, in the dry etching of the anti-reflection film, the etching time of the anti-reflection film of the step difference can be shortened, and a resist pattern having an appropriate thickness can be left. Thus, the resist pattern can be removed until the dry etching of the film to be processed is completed. Thus, the desired pattern can be suppressed from being deformed or lost when a desired pattern is formed on the film to be processed by dry etching.

[0028]

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

FIG. 1 is a diagram showing a first embodiment of a method of manufacturing a semiconductor device according to the present invention. This embodiment shows an example in which an antireflection film is selectively formed only in a region where a device pattern exists.

As shown in FIG. 1A, the semiconductor substrate 31
A film to be processed 32 is formed thereon, and then an antireflection film 33 is applied and formed.

As the material of the antireflection film 33, for KrF exposure, for example, a material obtained by using the materials shown in FIGS. 2A to 2C can be used. The anti-reflection coating material is cured by light exposure, and the anti-reflection coating is selectively formed in the region exposed by development.
It is an example of an antireflection film material for rF exposure. Further, as a material of the antireflection film 33, for KrF exposure, for example, a material obtained by using the materials shown in FIGS. 3A to 3C can be used. This anti-reflection coating material is an example of an anti-reflection coating material for KrF exposure in which the anti-reflection coating material is solubilized in a developing solution by light exposure and an anti-reflection film is selectively formed in a region other than the region exposed by development. By using the photosensitive anti-reflection film 33 made of these materials, the anti-reflection film 33 can be formed on the semiconductor substrate 31.

Next, the photosensitive anti-reflection film 33 is exposed to light,
By performing development and baking, an antireflection film 33a is selectively formed on a region where a device pattern is to be formed (region other than the local step 34) as shown in FIG. 1B.

Next, as shown in FIG. 1C, a resist film 35 is formed by coating.

The resist film 35 is selectively exposed and developed by an exposure device using an i-line or a KrF excimer laser as a light source, and developed to form a resist pattern 35a as shown in FIG.

Next, as shown in FIG. 1E, the antireflection film 33a is etched using the resist pattern 35a as a mask to form an antireflection film pattern 33b.
At this time, since the antireflection film 33a does not exist in the local step 34, there is no extremely thick portion. Therefore, the etching time of the antireflection film 33a can be reduced to a necessary minimum. As a result, the processed film 3
2 can obtain a resist remaining film sufficient for etching.

As shown in FIG. 1F, by etching the film 32 using the resist pattern 35a and the antireflection film pattern 33b as a mask, a desired film pattern 32a can be obtained.

FIG. 4 is a diagram showing a second embodiment of the method of manufacturing a semiconductor device according to the present invention. This embodiment shows an example in which an antireflection film is selectively formed so as to avoid a local step. This embodiment can be applied to a pattern (large pattern size) in which the dimensional fluctuation of the resist pattern in an area where the antireflection film does not exist can be tolerated.

As shown in FIG. 4A, the semiconductor substrate 41
A film 42 to be processed is formed thereon, and then an antireflection film 43 is formed by coating.

The photosensitive antireflection film 43 is exposed to light, developed and baked to form an antireflection film 43a so as to avoid a local step 44 as shown in FIG. 4B.

Next, as shown in FIG. 4C, a resist film 45 is formed by coating.

The resist film 45 is selectively exposed and developed by an exposure device using an i-line or a KrF excimer laser as a light source, and developed to form a resist pattern 45a as shown in FIG.

Next, as shown in FIG. 4E, using the resist pattern 45a as a mask, the antireflection film 43a is etched to form an antireflection film pattern 43b.
At this time, since the antireflection film 43a does not exist in the local step 44, there is no extremely thick portion. Therefore, the etching time of the antireflection film 43a can be shortened to a necessary minimum. As a result, the processed film 4
2 can obtain a resist remaining film sufficient for etching.

As shown in FIG. 4F, a desired film pattern 42a to be processed can be obtained by etching the film 42 using the resist pattern 45a as a mask.

[0044]

As described above, in the present invention, an anti-reflection film made of a photosensitive material is used, and this anti-reflection film is selectively formed on the film to be processed. The resist pattern can be left until the end of the dry etching, and the deformation and loss of the pattern at the time of forming a desired pattern of the film to be processed by the dry etching can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a method for manufacturing a semiconductor device of the present invention.

FIG. 2 is a view showing an example of a material constituting a photosensitive antireflection film used in the method for manufacturing a semiconductor device of the present invention.

FIG. 3 is a view showing an example of a material constituting a photosensitive antireflection film used in the method for manufacturing a semiconductor device of the present invention.

FIG. 4 is a diagram showing a second embodiment of the method for manufacturing a semiconductor device according to the present invention.

FIG. 5 is an explanatory diagram of pattern formation using an antireflection film in a conventional method for manufacturing a semiconductor device.

FIG. 6 is an explanatory diagram of a problem in pattern formation using a conventional antireflection film.

[Explanation of symbols]

 31 semiconductor substrate 32 processed film 32a processed film pattern 33 antireflection film 33a selectively formed antireflection film 33b antireflection film pattern 34 local step 35 resist 35a resist pattern 41 semiconductor substrate 42 processed film 42a processed Film pattern 43 Antireflection film 43a Selectively formed antireflection film 43b Antireflection film pattern

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03F 7/11 H01L 21/027 H01L 21/3065

Claims (7)

(57) [Claims] An anti-reflection film and a photoresist film are sequentially formed on a film to be processed, and a pattern of the photoresist film and the anti-reflection film is formed by patterning the photoresist film and the anti-reflection film. In a method of manufacturing a semiconductor device in which the film to be processed is etched using a mask as a mask, a material made of a photosensitive material is used as a material of the anti-reflection film, and the anti-reflection film is exposed to light using light exposure. Selectively formed on the film to be processed,
Here, the antireflection film is formed locally on the film to be processed.
Selective formation only in areas other than areas with large
And forming the photoresist film thereon. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the antireflection film is selectively formed only in a region where a device pattern exists. 3. The method of manufacturing a semiconductor device according to claim 1, wherein the antireflection film is selectively formed only in a region where the patterning is fine and a design rule of the semiconductor device is strict. Method. 4. The method of manufacturing a semiconductor device according to claim 1, wherein the patterning of the antireflection film is selectively performed.
Etching the antireflection film formed on
A method of manufacturing a semiconductor device. 5. The method of manufacturing a semiconductor device according to claim 1 , wherein the local step formed on the film to be processed reflects the shape of the surface of the semiconductor substrate on which the film to be processed is formed. A method for manufacturing a semiconductor device, comprising: 6. The method of manufacturing a semiconductor device according to claim 1, wherein the material of the antireflection film is formed by crosslinking by light exposure and selectively forming an antireflection film in the exposed region by development. A method for manufacturing a semiconductor device using a photosensitive material. 7. The method of manufacturing a semiconductor device according to claim 1, wherein the material of the anti-reflection film is solubilized in a developer by light exposure, and the anti-reflection film is selectively formed in a region other than the exposed region by development. A method of manufacturing a semiconductor device using a photosensitive material formed on a substrate.