JPH1187217A - Antireflection film material coating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evenly coat an antireflection film material which leaves no dissolved gas in the antireflection film by providing a deaerator for deaerating the antireflection film material in the antireflection material before it is discharged. SOLUTION: A wafer chuck 111 for holding a wafer 10 is provided in a cup 115 of a coating part 110 so as to arrange a nozzle arm 112, a deaerator unit 113 and a nozzle 114 above this wafer chuck 111. Next, an antireflection film material is pressurized with nitrogen gas, etc., to be fed to a material feeding piping 120 from a canister, so that the fed antireflection film material passes through the nozzle arm 112, the deaerator unit 13 vibrating through a filter 130, so as to deaerate the antireflection film material by the deaerator unit 113 for removing dissolved gas. Through these procedures, the antireflection film material can be evenly coated without leaving any dissolved gas in the antireflection film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-reflective coating material coating apparatus, and more particularly to an anti-reflective coating material suitable for patterning a fine resist using an anti-reflective coating on a substrate in a semiconductor device manufacturing process. The present invention relates to a coating device.

[0002]

2. Description of the Related Art As the degree of integration of LSIs has increased, the design rules have shrunk, and accordingly, there has been a demand for improvements in resist performance and in sophistication of resist development methods. Generally, the performance of a resist is considered to be better as the difference in dissolution rate between exposed and unexposed portions during development, that is, the larger the dissolution contrast, is. That is, as the dissolution contrast is larger, the cross-sectional shape of the resist pattern obtained by development becomes closer to a rectangle.
This is because, for example, differences in pattern conversion and variations during etching performed using this resist pattern as a mask in the etching step are reduced, and high-precision processing becomes possible. Further, the higher the dissolution contrast is, the higher the resolution of the resist is, and the finer the pattern can be formed.

Hitherto, various improvements have been made to resists in order to increase the dissolution contrast. One of them is to make the resist have a surface hardening effect. This surface hardening effect is an effect that when a developing solution comes into contact with the unexposed resist, the dissolution rate of the resist is extremely reduced. On the other hand, as another factor that affects the formation of a fine pattern as well as the dissolution contrast, there is substrate dependence of the pattern shape. In particular, since the refractive index is a function of the wavelength of light, changes with the shortening of the exposure wavelength,
The difference in the refractive index between the resist and the substrate determines the reflectivity from the substrate.

[0004] The complex refractive index of the substrate and the resist, respectively,
Assuming that Nsu (λ) and Nre (λ) (where λ is the exposure wavelength and the complex refractive index is a function of the wavelength), the reflectance R at the interface between the substrate and the resist is expressed by the following equation (1). Is done. R = | Nsu (λ) −Nre (λ) | ² / | Nsu (λ) + Nre (λ) | ² (1) Reflection of light from the substrate is a main cause of significantly degrading the patterning accuracy. In addition, suppression and control thereof are one of the main issues of microfabrication associated with shorter wavelengths.

As a method of suppressing the reflection of the substrate, a method of applying an antireflection film on the substrate by spin coating is being applied as a production method. The anti-reflection film is made of an organic resin having a sufficient absorption coefficient with respect to the exposure wavelength, and is formed by spin coating on a substrate or a coated resist and baking. Here, the antireflection film formed between the substrate and the resist is generally referred to as a lower antireflection film, and the antireflection film formed on the resist is generally referred to as an upper antireflection film. As a conventional antireflection film material application apparatus, an apparatus obtained by partially improving an existing resist application apparatus is used.

[0006]

As described above, by applying a resist having a high dissolution contrast and applying an antireflection film, the cross-sectional shape of the resist can be made nearly rectangular regardless of the underlying shape. Becomes possible. However, when applying an anti-reflective coating material using a conventional anti-reflective coating material coating apparatus, a development defect of a resist occurs, or a desired anti-reflective effect is not obtained, and pattern deterioration due to the influence of substrate reflection becomes apparent. A problem began to arise.

First, the development defect of the resist will be described. Here, the development defect of the resist means that when the exposed resist is developed using a photomask for forming a contact hole, a part to be a contact hole on the substrate is not opened in several to several tens of parts. A phenomenon that remains. The development defect of the resist will be described more specifically. Normally, as shown in FIG. 6, after a positive resist 2 is applied on a substrate 1, for example, an overlying antireflection film 3 is applied.
When the resist 2 is exposed and developed using a photomask, the resist 2 in the portion where the latent image 4 is formed is dissolved to form a contact hole.

However, the antireflection film material discharged from the nozzle of the antireflection film material application device and supplied onto the substrate 1 is pressurized at the time of discharge, but returns to the atmospheric pressure at the time of supply. The gas dissolved in the prevention film material elutes to form bubbles, so-called microbubbles are formed. That is, since the resist coating device only needs to discharge a resist material having a high solution viscosity from a nozzle, a pump-type pressurizing method is adopted. However, the anti-reflection film material coating device has a low solution viscosity. Must be discharged from the nozzle, and a pressure feeding method of pressurizing with nitrogen gas or the like is adopted. Therefore, in the conventional antireflection film material coating apparatus, gas often dissolves in the antireflection film material, and as a result, microbubbles are easily generated.

As shown in FIG. 7A, when the microbubbles 5 cover the portion of the resist 2 to be dissolved, that is, the portion where the latent image 4 is formed, The supply of the developer penetrated into the anti-reflection film 3 becomes insufficient, and the development does not proceed. This is because, in general, a resist having a high dissolution contrast has a high hydrophobicity on the surface, and a surface hardening layer is easily formed, so that the developer cannot enter the gap between the resist surface and the microbubbles attached to the surface. This is because the microbubbles are in a state of being attached for a long time.

[0010] As a result, as shown in FIG. 7B, a portion 2a which is not an opening and therefore does not become a contact hole, that is, a development defect occurs in the resist pattern obtained by development. If microbubbles exist in the underlying anti-reflection film, the refractive index in the underlying anti-reflection film changes, so that the desired anti-reflection effect cannot be obtained and the patterning accuracy is degraded. .

Next, the fact that the desired antireflection effect cannot be obtained will be described. Here, the anti-reflection film is roughly classified into a lower anti-reflection film and an upper anti-reflection film as described above. In general, an overlying anti-reflection film is effective in reducing the multiple interference effect (so-called standing wave effect) between the interface between the base and the resist, but depends on the base shape of the reflected light from various base reflection portions (so-called standing wave effect). Halation) cannot be reduced. However, only two steps of a washing step for removing the overlying anti-reflection film after the film formation and development of the overlying anti-reflection film are added, and the process can be easily constructed.

The basic principle of the anti-reflection coating is shown in FIG.
As shown in (A), the reflected light Ir ₁ of the incident light Ic reflected at the interface of the air / overlying antireflection film 3A and the interface between the incident light Ic and the resist 2 which is incident on the overlying antireflection film 3A. in by matching canceled by interference between reflected light Ir ₂ coming reflecting the principle that it is possible to eliminate the reflected light viewed from the resist 2 surface. As a result, the standing wave effect can be reduced. Naturally, an antireflection film material having a refractive index n satisfying this condition is selected, and Ir
_It is necessary to determine and control the optimum antireflection film thickness d in which ₁ and Ir ₂ cancel each other.

FIG. 9A shows a case where the overlying anti-reflection film 3A is not formed. As described above, multiple interference occurs between the reflected light from the substrate 1 and the interface between the resist 2 and
This shows how the shape of the latent image 4 in the resist 2 has deteriorated. FIG. 2B shows a case where the antireflection film 3A is formed on the upper surface, and the standing wave effect due to the multiple interference is eliminated, and the shape of the latent image 4 in the resist 2 is kept good. Is shown.

However, when the microbubbles 5 are generated in the overlying antireflection film 3A, as shown in FIG. 3C, the antireflection effect is not obtained and the standing wave effect causes the resist 2 to have an effect in the resist 2. The shape of the latent image 4 has deteriorated. The reason for this is
As described above, the anti-reflection effect is determined by the refractive index n and the anti-reflection film thickness d of the anti-reflection film material, but these values are changed by the microbubbles 5.

In addition, since the lower anti-reflection film is generally formed under the resist, there arises a new process problem of peeling by etching. The reflection can be directly reduced, and not only the standing wave effect but also the halation can be reduced.

The basic principle of the underlying anti-reflection film is shown in FIG.
(B), the reflected light Ir ₃ coming reflected by the interface of air / resist 2 of the incident light Ic, and reflected at the interface between the antireflection film 3A placed under incident on the resist 2 The principle is that the reflected light Ir ₄ viewed from the surface of the resist 2 can be eliminated by causing the reflected light Ir ₄ to interfere with and cancel each other. As a result, the standing wave effect and halation can be reduced. Naturally, it is necessary to select an antireflection film material having a refractive index nn that satisfies this condition, and determine and control an optimum antireflection film thickness dd at which Ir ₃ and Ir ₄ cancel each other.

FIG. 10A shows a case in which the underlying anti-reflection film 3B is not formed.
The figure shows that multiple interference occurs between the reflected light from the substrate and the interface between the resist 2 and the shape of the latent image 4 in the resist 2 is deteriorated. FIG. 2B shows the lower antireflection film 3.
In this case, B is formed, and the standing wave effect due to multiple interference is lost, and the shape of the latent image 4 in the resist 2 is well maintained.

However, when the microbubbles 5 are generated in the lower antireflection film 3B, as shown in FIG. 3C, the antireflection effect is not obtained and the standing wave effect causes the resist 2 in the resist 2. The shape of the latent image 4 has deteriorated. The reason for this is
As described above, the antireflection effect is determined by the refractive index nn and the antireflection film thickness dd of the antireflection film material, but these values are changed by the microbubbles 5.

The present invention has been made in view of the above circumstances, and provides an antireflection film material coating apparatus capable of uniformly applying an antireflection film material without leaving dissolved gas in the antireflection film. The purpose is to do.

[0020]

SUMMARY OF THE INVENTION According to the present invention, there is provided an anti-reflective coating material coating apparatus for discharging and applying an anti-reflective coating material onto a substrate. And at least one degassing means for degassing the antireflection film material. Further, according to the present invention, in the present invention, there is provided an anti-reflection film material coating apparatus for discharging and applying an anti-reflection film material onto a substrate. At least one degassing means for degassing, a dissolved gas amount detecting means for detecting an amount of dissolved gas in the antireflection film material passing through the degassing means, and from the dissolved gas amount detecting means to the degassing means. A bypass pipe for bypassing the
This is achieved by providing a three-way valve that is provided between the dissolved gas amount detecting means and the bypass pipe and switches a supply direction of the antireflection film material through the dissolved gas amount detecting means.

Further, according to the present invention, there is provided an anti-reflection coating material coating apparatus for discharging and coating an anti-reflection coating material on a substrate. This is achieved by providing a plurality of capillaries inside the anti-reflective coating material through which the anti-reflective coating material passes and evacuating the inside to degas the anti-reflective coating material passing through the capillaries.

According to the above structure, the dissolved gas in the anti-reflection film material can be removed before the anti-reflection film material is discharged onto the substrate, so that generation of microbubbles in the anti-reflection film can be suppressed. Accordingly, a fine resist pattern can be formed with high accuracy, and pattern formation deterioration due to a reduction in development defects and an antireflection effect can be suppressed.

[0023]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The embodiment described below is a preferred specific example of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description.

FIG. 1 is an overall configuration diagram showing a first embodiment of an antireflection film material coating apparatus according to the present invention. The anti-reflective coating material coating apparatus 100 is provided with a coating section 110 for coating the anti-reflective coating material, and a separate canister (metal container) for storing the coating section 110 and the anti-reflective coating material or a factory centralized apparatus. The pipes are connected by a material supply pipe 120 for supplying an anti-reflection film material.

The coating section 110 includes a wafer chuck 111 for holding the wafer 10 and the wafer chuck 1.
11 and an anti-reflective coating material
The nozzle arm 112, the deaeration unit 113, and the nozzle 114 that supply the air to the nozzles are disposed in the cup 115. The wafer chuck 111 has a central axis 111a connected to a motor, and is rotatable about the central axis 111a. A nozzle 114 is connected to one end of the nozzle arm 112 via a deaeration unit 113,
A material supply pipe 120 is connected to the other end, and is rotatable about a rotation axis at the other end in a plane parallel to the wafer 10 held by the wafer chuck 111. A filter 130 for filtering the antireflection film material is connected to the material supply pipe 120 in the middle thereof.

In such a configuration, the anti-reflection film material is pressurized by nitrogen gas or the like and supplied to the material supply pipe 120 from the canister or factory centralized pipe. At this time, nitrogen and the like are dissolved in the antireflection film material together with oxygen. The anti-reflective coating material supplied to the material supply pipe 120 reaches the oscillating nozzle arm 112 through the filter 130, but when passing through the filter 130, contained foreign matter is removed. And the nozzle arm 1
The anti-reflection film material supplied to the deaeration unit 11
3 to the nozzle 114, but the deaeration unit 113
When passing through, the anti-reflective coating material is degassed and the dissolved gas is removed. The anti-reflective coating material from which the contained foreign matter and dissolved gas have been removed in this way is discharged from the nozzle 114 onto the rotating wafer 10 and applied.

The inside of the deaeration unit 113 is, for example, 8 ×
Evacuation (decompression) to about 10 ⁴ Pa (600 mmHg)
As a result, the anti-reflective coating material can be degassed. Here, as an example of the degassing effect of the degassing unit 113, the antireflection coating material before degassing, in particular, an organic solvent in the lower antireflection coating material or pure water in the upper antireflection coating material. When the amount of dissolved gas therein was 7.5 mg / l, the amount of dissolved gas after degassing through this degassing unit 113 was 4.1 mg / l, which was almost halved.

As described above, according to the first embodiment, since the antireflection film material is degassed by the degassing unit 113 provided on the nozzle arm 112, the material discharged from the nozzle 114 is discharged. The amount of dissolved gas in the antireflection film material immediately before the reflection can be greatly reduced. As a result, development defects due to the generation of microbubbles can be effectively suppressed, and a fine resist pattern on a highly reflective substrate can be formed by obtaining a desired antireflection effect.

FIG. 2 is an overall configuration diagram showing a second embodiment of the antireflection coating material coating apparatus according to the present invention. The anti-reflection coating material coating apparatus 200 has substantially the same configuration as the anti-reflection coating material coating apparatus 100 of the first embodiment, but the deaeration unit 213 is provided in the middle of a material supply pipe 120 extending from a canister or a factory centralized pipe. And the filter 130
It has a different configuration in that it is also attached immediately before the.

According to the second embodiment, the antireflection film material is degassed by the degassing units 113 and 213 provided in the nozzle arm 112 and the material supply pipe 120. The amount of dissolved gas in the anti-reflective coating material immediately before being discharged from the substrate can be further greatly reduced. As a result, it is possible to obtain an effect equal to or greater than that of the first embodiment.

FIG. 3 is a block diagram showing a coating section in a third embodiment of the anti-reflection coating material coating apparatus according to the present invention. The anti-reflection film material application device 300 has substantially the same configuration as the anti-reflection film material application devices 100 and 200 of the first embodiment or the second embodiment.
13 is different in that it is also attached to the nozzle 114.

According to the third embodiment, the anti-reflection film is formed by the deaeration unit 113 provided on the nozzle arm 112 or the deaeration units 113 and 213 provided on the nozzle arm 112 and the material supply pipe 120. Since the material is degassed and the antireflection film material is degassed by the degassing unit 313 also provided in the nozzle 114, the dissolved gas in the antireflection film material immediately before being discharged from the nozzle 114 The amount can be significantly reduced more than the above embodiments. As a result, effects equal to or higher than those of the above embodiments can be obtained. still,
Although the effect is reduced to some extent, an antireflection film material coating apparatus in which only the nozzle 114 is provided with the deaeration unit 313 may be used.

FIG. 4 is a view showing the configuration of a coating section in a fourth embodiment of the antireflection coating material coating apparatus according to the present invention. The anti-reflection film material application device 400 has substantially the same configuration as the anti-reflection film material application devices 100, 200, and 300 of the first, second, or third embodiment, but has a deaeration unit. The configuration is different in that a bypass pipe 415 for bypassing the front and rear of the 113 is provided in the nozzle arm 112.

One end of the bypass pipe 415 is connected to the nozzle arm 112 via a three-way valve 416 that can be switched by a control signal. Degassing unit 1
Nozzle arm 112 at a portion between the valve arm 13 and the three-way valve 416
Is provided with a dissolved gas amount detector 417 for detecting the dissolved gas amount in the antireflection film material in the nozzle arm 112.

In such a configuration, the antireflection film material supplied to the nozzle arm 112 passes through the deaeration unit 113 while the three-way valve 416 is switched by a predetermined control signal to shut off the bypass pipe 415. 11
4, when passing through the degassing unit 113, the antireflection film material is degassed and the dissolved gas is removed.
At this time, the dissolved gas amount in the antireflection film material is measured by the dissolved gas amount detector 417 at the outlet side of the degassing unit 113, and when the measured dissolved gas amount is equal to or less than a predetermined value, The anti-reflection coating material is supplied to the nozzle 114 and discharged.

On the other hand, when the measured dissolved gas amount is higher than a predetermined value, the three-way valve 416 is switched by a predetermined control signal to switch the bypass pipe 41.
Open 5 Then, the anti-reflection film material that has passed through the deaeration unit 113 is returned to the inlet side of the deaeration unit 113 through the bypass pipe 415, so that the deaeration unit 1
Degassed through 13 to remove dissolved gases. In this way, degassing is repeated until the amount of dissolved gas in the anti-reflection film material that has passed through the degassing unit 113 becomes equal to or less than a predetermined value, and the amount of dissolved gas becomes equal to or less than a predetermined value. Then, the anti-reflection film material is supplied to the nozzle 114 and discharged.

As described above, according to the fourth embodiment, the anti-reflection coating material whose dissolved gas amount has been reduced to a predetermined value or less can be discharged from the nozzle 114. As a result, effects equal to or higher than those of the above embodiments can be obtained. The bypass pipe 415 may be configured to bypass not only the area before and after the degassing unit 113 but also a combination of a plurality of degassing units 113, 213, and 313, or a single area before and after.

FIG. 5 is a view showing the configuration of a coating section in a fifth embodiment of the antireflection coating material coating apparatus according to the present invention. The anti-reflection coating material coating apparatus 500 is the same as the anti-reflection coating material coating apparatuses 100, 200, and 3 of the first, second, third, or fourth embodiment.
00 and 400, but the nozzle arm 51
Part or all of the nozzle arms 512 include a plurality of capillaries 512a that can be evacuated through the pipe wall, and are provided with capillaries 512a arranged apart from each other.
Has a different configuration in that the inside thereof is configured to be able to evacuate.

Also according to the fifth embodiment, the inside of the nozzle arm 512 is evacuated to a vacuum so that the capillary tube 5 is evacuated.
Since the anti-reflection coating material passing through 12a is degassed, the amount of dissolved gas in the anti-reflection coating material immediately before being discharged from the nozzle 114 can be significantly reduced as compared with the above embodiments. As a result, effects equal to or higher than those of the above embodiments can be obtained. Although the effect is somewhat reduced, an anti-reflection film material coating apparatus provided with only the nozzle arm 512 constituted by the capillary tube 512a may be used.

The state of the wafer 10 when the anti-reflection coating material was applied using the anti-reflection coating material coating apparatuses 100 to 500 of the above embodiments was examined. The lower anti-reflection film discharges the anti-reflection film material on the high reflection substrate and the upper anti-reflection film on the resist.
1 was rotated, for example, at 1000 revolutions per minute for about 2 to 3 seconds, and then, for example, rotated at 3000 revolutions per minute for about 25 seconds to apply the antireflection film. Then, when a resist pattern was formed, 0.25 μmL after development
The result of the line width variation in the wafer surface of / S was 0.0 at 3σ.
A result of 15 μm was obtained. This result was sufficient as the line width specification after development, against the required device specification of ± 0.025.

[0041]

As described above, according to the present invention, an antireflection film material can be uniformly applied without leaving dissolved gas in the antireflection film.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of an antireflection film material coating apparatus according to the present invention.

FIG. 2 is an overall configuration diagram showing a second embodiment of an antireflection film material coating apparatus according to the present invention.

FIG. 3 is a configuration diagram showing a coating unit in a third embodiment of the antireflection film material coating device according to the present invention.

FIG. 4 is a configuration diagram showing a coating unit in a fourth embodiment of the antireflection film material coating device according to the present invention.

FIG. 5 is a configuration diagram showing a coating unit in a fifth embodiment of the antireflection film material coating device of the present invention.

FIG. 6 is a cross-sectional side view of a substrate when a normal antireflection film is formed.

FIG. 7 is a cross-sectional side view of a substrate when an antireflection film is formed by a conventional antireflection film material coating apparatus.

FIG. 8 is a cross-sectional side view for explaining the principle of the upper antireflection film and the lower antireflection film.

FIG. 9 is a schematic diagram showing a state in which microbubbles prevent a desired antireflection effect in the antireflection film placed above.

FIG. 10 is a schematic view showing a state in which microbubbles prevent a desired antireflection effect in a lower antireflection film.

[Explanation of symbols]

10 ... wafer, 100, 200, 300, 40
0, 500: anti-reflective coating material coating device, 110
・ Coating part, 111 ・ ・ ・ Wafer chuck, 112, 5
12 ... Nozzle arm, 113, 213, 313 ...
・ Deaeration unit, 114 ・ ・ ・ Nozzle, 115 ・ ・ ・ Cup, 120 ・ ・ ・ Pipe for supplying anti-reflective coating material, 130
... Filter, 415 ... Bypass piping, 416
..Three-way valves, 417... Dissolved gas amount detectors, 512a
... Capillaries

Claims (5)

[Claims] 1. An anti-reflection coating material applying apparatus for discharging and applying an anti-reflection coating material onto a substrate, wherein at least one deaeration for degassing the anti-reflection coating material before discharging the anti-reflection coating material. An anti-reflection coating material coating apparatus, comprising: 2. An anti-reflective coating material coating apparatus for discharging and applying an anti-reflective coating material onto a substrate, wherein at least one degassing step is performed before the anti-reflective coating material is discharged. Gas means; dissolved gas amount detecting means for detecting the dissolved gas amount in the antireflection film material passing through the degassing means; a bypass pipe for bypassing from the dissolved gas amount detecting means to the degassing means; A three-way valve provided between the dissolved gas amount detecting means and the bypass pipe to switch a supply direction of the antireflection film material through the dissolved gas amount detecting means; apparatus. 3. The three-way valve is switched to the discharge side when the dissolved gas amount in the anti-reflection film material is equal to or less than a predetermined value, and when the dissolved gas amount in the anti-reflection film material is higher than a predetermined value. The anti-reflection film material supply device according to claim 2, wherein the device is switched to the bypass pipe side. 4. An anti-reflective coating material coating apparatus for discharging and applying an anti-reflective coating material onto a substrate, wherein a plurality of capillaries through which the anti-reflective coating material passes are provided before discharging the anti-reflective coating material. An anti-reflection film material supply device, comprising: a tube for evacuating the inside thereof and degassing the anti-reflection film material passing through the inside of the capillary. 5. The apparatus according to claim 4, wherein the plurality of capillaries are arranged at a predetermined interval from each other.