JPH05267126A - Photolithographic method using x-ray - Google Patents

Abstract

PURPOSE:To obtain a highly accurate photo-resist pattern having required thickness easily by conducting repeat exposure step and 1:1 projection aligning step in combination. CONSTITUTION:Repeat exposure step using X-rays is performed to a photo-resist film 2 formed onto a supporter 1 to form a mask being employed in next 1:1 projection aligning step. 1:1 projection aligning step is conducted to the photo- resist film 2 through the mask, and a mask pattern is transferred in the depth direction of the photo-resist film 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photolithography method using X-rays, and more particularly to a photolithography method using X-rays for transferring a fine pattern on a photoresist film with high resolution.

[0002]

2. Description of the Related Art Conventionally, when a fine pattern is transferred onto a photoresist film by a photolithography technique, exposure using g-line and i-line which can obtain high resolution is performed. Then, for example, in recent years, excimer laser lithography, a phase shift method, and the like have been developed for a photolithography process of a semiconductor device which is further miniaturized. However, this method has a problem that it is difficult to obtain a practical pattern of 0.25 μm or less.

Therefore, as a method for obtaining a practical pattern of 0.25 μm or less, a proximity method using X-rays (wavelength = 4 to 20Å) has been introduced. This method
Through a transmission type equal-magnification mask on which a desired pattern is formed,
The pattern on the transmission type equal-magnification mask is transferred to the photoresist film by irradiating the photoresist film with X-rays. It has been confirmed that this method is an excellent transfer technique capable of obtaining extremely high resolution and capable of forming a thick photoresist film with a very good shape. However, since the proximity method is the same-magnification projection, there is a problem that the accuracy required for the mask is very strict and the position accuracy and the overlay accuracy cannot be sufficiently obtained. Further, there has been a problem that a high-precision mask manufacturing technique has not been established yet.

In order to solve such a problem, therefore, a reduction projection exposure method has been introduced in which a reflective mask is used, the mask is irradiated with X-rays, and the reflected light is irradiated onto the photoresist film. There is. This method is 0.05μ
The pattern of m can be transferred with high precision, and since the projection is reduced, the mask can be easily manufactured. However,
Due to the limitation of the multilayer film that can be used as an X-ray reflecting mirror (reflection type mask), the wavelength of X-ray that can be used at present is 100 Å or more. X-rays having a wavelength of 100 Å or more are largely absorbed in the photoresist film. Therefore, for example, 100
With X-rays having a wavelength of up to 200 Å, it is not possible to pattern a photoresist film having a large thickness, for example, only a pattern having a photoresist film thickness of about 0.3 μm can be obtained. There is a problem that a resist pattern cannot be obtained.

Therefore, in the reduction projection exposure using the X-ray, a photoresist film containing Si is formed on the thick transfer layer photoresist film, and in the reduction projection exposure,
Only the photoresist film containing Si is exposed and patterned, and the photoresist film for transfer layer is subjected to anisotropic etching (O) using oxygen as a mask with the patterned photoresist film containing Si. _2- R
The method of performing IE) and patterning the photoresist film for the transfer layer is introduced. Here, the Si-containing photoresist film is formed with a film thickness equal to or less than the penetration depth of the X-ray used in the reduction projection exposure. In this method, since the photoresist film for the transfer layer is patterned by O ₂ -RIE, 100 to 200 Å
A photoresist pattern having a required thickness can be obtained even by using X-rays having wavelengths of.

[0006]

However, the above-mentioned O
_In the reduction projection exposure method using _2- RIE, the O ₂
There is a problem that the base damage due to RIE is large and the reliability of the semiconductor device is hindered. In addition, the O ₂
Since RIE is performed in a vacuum device, there is a problem that throughput is poor.

An object of the present invention is to solve such a problem, that is, mask production is easy, reduction projection exposure having high resolution, and excellent pattern transfer ability in the depth direction. A photolithography method using X-rays, which can easily obtain a photoresist pattern having a required thickness and having a highly accurate pattern transferred by performing it in combination with 1 × projection exposure having The purpose is to provide.

[0008]

To achieve this object, the present invention provides a photoresist film coated on a support,
In a photolithography method using X-rays, which transfers a desired pattern using X-rays, a first step of forming a photoresist film that is sensitive to X-rays on the support, and X-rays on the photoresist film. A second step of selectively performing reduction projection exposure using the above to form an image portion and a non-image portion, and a third step of selectively diffusing an X-ray absorber into the image portion of the photoresist film, A fourth step of selectively removing the non-image portion of the photoresist film, and the X-ray absorption using the photoresist film, in which the X-ray absorber is diffused, as a mask in the photoresist film after the selective removal. And a fifth step of performing equal-magnification projection exposure using X-rays of a wavelength absorbed by the body, and a photolithography method using X-rays.

Then, in the photolithography method using X-rays, which transfers a desired pattern onto the photoresist film coated on the support, the first photo-sensitive film on the support is exposed to the X-rays. A first step of forming a resist film; and a second step of exposing the first photoresist film to an X-ray having a wavelength containing an X-ray absorber and having a small amount absorbed by the X-ray absorber. The second step of forming a photoresist film, and the second photoresist film are selectively subjected to reduction projection exposure using X-rays having a wavelength that is absorbed by the X-ray absorber, thereby reducing the image area. And a second step of forming a non-image portion, a third step of selectively removing the non-image portion of the second photoresist film, and a third step after the selective removal of the first photoresist film. Using the second photoresist film as a mask There is provided a photolithographic method using X-rays, characterized in that it comprises a fourth step of performing an equal magnification projection exposure using X-rays of a wavelength that is absorbed by the X-ray absorber.

Further, in the photolithography method using X-rays, which transfers a desired pattern onto the photoresist film coated on the support, the first exposure to the support on the support is performed. A first step of forming a photoresist film, a second step of forming an X-ray absorber layer on the first photoresist film, and a second step of exposing the X-ray absorber layer to X-rays. And a fourth step of selectively performing reduced projection exposure using X-rays on the second photoresist film to form an image portion and a non-image portion, The fifth step of selectively removing the non-image portion of the second photoresist film, and the X-ray etching using the second photoresist film after the selective removal as a mask
A sixth step of removing the second photoresist film after selectively removing the line absorber layer, and X after the selective removal.
A seventh step of subjecting the first photoresist film to equal-magnification projection exposure using X-rays of a wavelength absorbed by the X-ray absorber layer, using the line absorber layer as a mask. The present invention provides a photolithography method using X-rays.

Further, in a photolithography method using X-rays, which transfers a desired pattern to a photoresist film coated on a support, the first photo-sensitive material is exposed to the X-rays on the support. A first step of forming a positive type photoresist film, and a second positive type having a higher sensitivity than the first positive type photoresist film and being exposed to X-rays on the first positive type photoresist film Second step of forming a photoresist film, and third step of selectively performing reduction projection exposure using X-rays on the second positive photoresist film
A step, a fourth step of selectively removing the exposed portion of the second positive photoresist film, and a second step after the selective removal.
5th step of subjecting the positive type photoresist film and the first positive type photoresist film exposed by the selective removal to whole surface exposure using X-rays having the same wavelength as the reduction projection exposure, and the whole surface exposure A sixth step of forming an X-ray absorber layer on the upper surfaces of both positive photoresist films afterward, which is thinner than the second positive photoresist film, and the second positive photoresist film and The seventh step of selectively removing the X-ray absorber layer formed on the upper surface thereof, and the X-ray absorber layer after the selective removal as a mask are used to form the X-ray An eighth step of performing equal-magnification projection exposure using X-rays of a wavelength absorbed by the line absorber layer is provided, and a photolithography method using X-rays is provided.

Further, in a photolithography method using X-rays, which transfers a desired pattern to the photoresist film coated on the support, the positive type of X-rays is exposed on the support. The first step of forming a photoresist film, and X on the positive photoresist film
A second step of selectively performing reduced projection exposure using a line, a third step of selectively removing the exposed portion of the positive photoresist film, and a positive photoresist film after the selective removal, A fourth step of performing an overall exposure using X-rays having the same wavelength as the reduction projection exposure, and a positive photoresist film after the selective removal on the upper surface of the positive photoresist film after the overall exposure A fifth step of forming an X-ray absorber layer having a film thickness smaller than a gap, a sixth step of selectively removing the positive photoresist film on which the X-ray absorber layer is formed, and the selective step Using the removed X-ray absorber layer as a mask,
Photolithography using X-rays, comprising: a seventh step of subjecting the positive photoresist film to equal-magnification projection exposure using X-rays of a wavelength absorbed by the X-ray absorber layer. It provides a method.

[0013]

According to the first aspect of the present invention, by selectively performing reduction projection exposure using the X-rays on the photoresist film which is exposed to the X-rays, an upper layer portion of the photoresist film is formed. Image areas and non-image areas can be formed. Then, by selectively diffusing the X-ray absorber in the image portion and selectively removing the non-image portion, a photoresist film in which the X-ray absorber is diffused is formed on the photoresist film. A fine pattern can be formed. Next, by using the fine pattern as a mask and performing equal-magnification projection exposure using X-rays having a wavelength absorbed by the X-ray absorber,
The fine pattern can be accurately transferred in the depth direction of the photoresist film.

That is, the mask for equal-magnification projection exposure can be formed by patterning by the reduction projection exposure. Therefore, the same-magnification projection exposure can be performed using a mask on which a very high-precision fine pattern is formed, without difficulty in manufacturing the mask. Also,
Since the fine pattern obtained by the reduction projection exposure may be formed with a film thickness that can function as a mask for the same-magnification projection exposure, the film thickness obtained by the reduction projection exposure is sufficient. .. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be compensated for each other. Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

According to the second aspect of the invention, an X-ray absorber is contained on the first photoresist film that is exposed to the X-rays, and the amount absorbed by the X-ray absorber is small. A second photoresist film that is sensitive to X-rays of a wavelength is formed, and reduction projection exposure using X-rays of a wavelength that is less absorbed by the X-ray absorber is selected for the second photoresist film. By doing so, the image portion and the non-image portion can be formed in the second photoresist film. Then, by selectively removing the non-image portion, the first image
A fine pattern made of the second photoresist film can be formed on the photoresist film. Next, by using the fine pattern as a mask and performing equal-magnification projection exposure using X-rays having a wavelength absorbed by the X-ray absorber, the fine pattern is formed in the depth direction of the first photoresist film. The pattern can be transferred accurately.

That is, the mask for equal-magnification projection exposure can be formed by patterning by the reduction-projection exposure, and the fine pattern obtained by the reduction-projection exposure is a mask for the same-magnification projection exposure. The film thickness obtained by the reduction projection exposure is sufficient because it can be formed with a film thickness capable of performing the above function. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be compensated for each other. Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

According to the third aspect of the invention, the first photoresist film that is exposed to the X-rays, the X-ray absorber layer, and the second photoresist film that is exposed to the X-rays are sequentially formed. After that, the second photoresist film is selectively subjected to reduction projection exposure using X-rays, so that the second photoresist film is exposed.
An image portion and a non-image portion can be formed on the photoresist film of 1. Then, after selectively removing the X-ray absorber layer formed on the non-image area and the area corresponding thereto, the second photoresist film is further removed to remove the first photoresist. A fine pattern made of an X-ray absorber layer can be formed on the resist film. next,
By performing equal-magnification projection exposure using X-rays having a wavelength absorbed by the X-ray absorber layer using the fine pattern as a mask, the fine pattern is formed in the depth direction of the first photoresist film. It can be transferred accurately.

That is, the mask for equal-magnification projection exposure can be formed by patterning by the reduction-projection exposure, and the fine pattern obtained by the reduction-projection exposure can be used for the same-magnification projection exposure. Since the film may be formed to have a film thickness that can function as a mask, the film thickness obtained by the reduction projection exposure is sufficient. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be compensated for each other. Further, since the mask for projection exposure of equal size can be directly formed on the photoresist film,
It is possible to further improve the resolution of the same-magnification projection exposure. Therefore, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

Further, according to the invention of claim 4, X
After forming a second positive photoresist film which is more sensitive than the first positive photoresist film and more sensitive to X-rays on the first positive photoresist film which is exposed to the rays,
By selectively performing reduced projection exposure using X-rays on the second positive photoresist film, and then selectively removing the exposed portion of the second positive photoresist film,
A fine pattern made of the second positive photoresist film may be formed on the first positive photoresist film. Next, the second positive photoresist film after the selective removal and the exposed first positive photoresist film were subjected to whole surface exposure using X-rays having the same wavelength as in the reduction projection exposure. Then, an X-ray absorber layer is formed on the upper surfaces of both the positive photoresist films so as to have a smaller film thickness than the second positive photoresist film, and then the second positive photoresist film and the second positive photoresist film and the same are formed. By selectively removing the X-ray spherical layer formed on the upper surface, a fine pattern made of an X-ray absorber layer can be formed on the first positive photoresist film.

That is, since the X-ray absorber layer is formed to have a smaller film thickness than the second positive photoresist film, the step of removing both positive photoresist films subjected to the whole surface exposure. Thus, for example, when a process using a developing solution is performed, the developing solution penetrates into the second positive photoresist film, but the first positive photoresist film does not absorb the X-ray. The body acts as a mask and the developer does not easily penetrate. In addition, the second positive type photoresist film is the first
Since the sensitivity is higher than that of the positive type photoresist film of No. 3, it is more easily developed. Therefore, only the second positive photoresist film is easily lifted off without adversely affecting the first positive photoresist film. Therefore, a fine pattern composed of the X-ray absorber layer can be formed on the first positive photoresist film.

Next, by using the fine pattern composed of the X-ray absorber layer as a mask, an equal-magnification projection exposure is carried out using X-rays having a wavelength absorbed by the X-ray absorber layer, whereby the first
The fine pattern can be accurately transferred in the depth direction of the positive photoresist film. That is, the patterning of the mask for the equal-magnification projection exposure can be performed by the reduction projection exposure, and the fine pattern made of the second positive photoresist film obtained by the reduction projection exposure is formed later. Since the X-ray absorber layer may be formed to a thickness that allows formation of the X-ray absorber layer, the film thickness obtained by the reduction projection exposure is sufficient. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be compensated for each other.
Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. Therefore, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

Further, according to the invention of claim 5, after the reduction projection exposure using the X-ray is selectively performed on the positive type photoresist film which is exposed to the X-ray, the photoresist is concerned. By selectively removing the exposed portion of the film, a fine pattern can be formed on the positive photoresist film. Next, the positive photoresist film on which the fine pattern is formed is subjected to full-surface exposure using X-rays of the same wavelength as the reduction projection exposure, and then the selective photoresist is applied to the upper surface of the positive photoresist film. An X-ray absorber layer is formed with a film thickness smaller than the gap generated in the positive photoresist film after removal, and then the positive photoresist film on which the X-ray absorber layer is formed is selectively removed. By doing so, a fine pattern made of an X-ray absorber layer can be formed on the positive photoresist film.

That is, since the X-ray absorber layer is formed with a thickness smaller than the gap of the positive photoresist film, it is possible to remove the positive photoresist film which has been subjected to the entire surface exposure. For example, when a process using a developing solution is performed, the developing solution penetrates into the convex part (the unexposed part in the reduction projection exposure) of the positive photoresist film, but the concave part (the reduction projection exposure). In the exposed portion), the X-ray absorber serves as a mask and the developer is unlikely to penetrate. Therefore, only the convex portion of the positive photoresist film is lifted off. Therefore, a fine pattern composed of the X-ray absorber layer can be formed on the positive photoresist film.

Next, by using the fine pattern composed of the X-ray absorber layer as a mask, equal-magnification projection exposure is performed using X-rays having a wavelength absorbed by the X-ray absorber layer, whereby the positive-type photomask The fine pattern can be accurately transferred in the depth direction of the resist film. That is, the patterning of the mask for the equal-magnification projection exposure can be performed by the reduction projection exposure, and the fine pattern made of the second positive photoresist film obtained by the reduction projection exposure is formed later. Since the X-ray absorber layer may be formed to a thickness that allows formation of the X-ray absorber layer, the film thickness obtained by the reduction projection exposure is sufficient. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be compensated for each other. Also,
Since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. Therefore, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

[0025]

Embodiments of the present invention will now be described with reference to the drawings. In Examples 1 to 5 described below, SOR in which a wavelength band can be arbitrarily determined by selecting a mirror and a filter as a light source used for each exposure
(For example, "AUROR" (trade name); manufactured by Sumitomo Heavy Industries) was used. In the reduction projection exposure, a Mo / Si multilayer film and a Schwart-Schulz type reflection optical system were used as a pattern transfer mask. (Embodiment 1) FIGS. 1 to 6 are process diagrams showing a photolithography method using X-rays according to Embodiment 1 of the present invention.

In the step shown in FIG. 1, a photoresist film 2 which is exposed to X-rays is formed on the support 1 with a film thickness of about 1.3 μm. In this embodiment, the photoresist film 2
A positive type “PLAZMASK (trade name), made by Nippon Synthetic Rubber” made of novolac resin and excellent in dry etching resistance was used as the above. Next, in the step shown in FIG. 2, the photoresist film 2 obtained in the step shown in FIG.
Then, reduction projection exposure is performed using X-ray 3 having a wavelength of 130Å. In this reduction projection exposure, the upper layer 0.3 μm of the photoresist film 2 is exposed, and this portion becomes the exposed portion 4. Furthermore, in the reduction projection exposure, it is possible to sufficiently resolve up to a width of 0.05 μm. Then, the entire surface of the photoresist film 2 after the reduction projection exposure is irradiated with a dose of 800 to 1000.
UV irradiation of about mJ / cm ² is performed.

Next, in the step shown in FIG. 3, an unexposed portion of the photoresist film 2 obtained in the step shown in FIG. 2 is selectively silylated using an organic silane-based gas to diffuse the X-ray absorber. Then, a photoresist film 5 is formed. This silylation is carried out until the Si content in the unexposed area becomes saturated. Then, this Si is an X-ray absorber, and absorbs the X-rays 7 used for equal-magnification projection exposure performed in a later step.

Next, in the step shown in FIG. 4, the exposed portion 4 obtained in the step shown in FIG. 2 is selectively removed, and a photoresist in which an X-ray absorber is diffused on the photoresist film 2. A fine pattern made of the film 5 is formed. This fine pattern serves as a mask for equal-magnification projection exposure that will be performed in a later step. Since this mask is formed by patterning by reduction projection exposure, it has extremely high accuracy.

Next, in the step shown in FIG. 5, the photoresist film 5 in which the X-ray absorber obtained in the step shown in FIG. 4 is diffused.
Is used as a mask, the photoresist film 2 has a wavelength of 4
The same-magnification projection exposure using 4 to 80 Å X-ray 7 is performed. At this time, for example, the long wavelength side of the absorption edge of C is used with a width of about 10Å. The X-rays 7 having a wavelength of 44 to 80 Å are absorbed by the X-ray absorber, and therefore, the exposed portion 4 is other than the photoresist film 5 region where the X-ray absorber is diffused. By doing so, the fine pattern can be accurately transferred in the depth direction of the photoresist film 2.

Next, in the step shown in FIG. 6, the exposed portion 4 obtained in the step shown in FIG. 5 is selectively removed so that a highly precise pattern having a required film thickness can be formed on the support 1. The transferred photoresist pattern is formed. Although a positive type photoresist is used in this embodiment, a negative type photoresist film may be used. Then, in this case, the X-ray absorber diffuses to the exposed portion. Second Embodiment Next, a second embodiment according to the present invention will be described with reference to the drawings.

7 to 11 are process diagrams showing a photolithography method using X-rays according to the second embodiment of the present invention. In the step shown in FIG. 7, a first photoresist film 12 that is exposed to X-rays is formed on the support 1 with a film thickness of 1.0.
It is formed with a thickness of about μm. In the present embodiment, as the first photoresist film 12, a positive type “SAL601-ER7 (trade name), manufactured by Shipley Co.” made of novolac resin and excellent in dry etching resistance was used. Next, on the first photoresist film 12, an X-ray having a wavelength that contains Si as an X-ray absorber and is absorbed by the X-ray absorber is small.
The second photoresist film 8 which is exposed to the lines has a film thickness of 0.
It is formed with a thickness of about 3 μm. In this embodiment, “FH-SP (trade name), manufactured by Fuji Hunt” is used as the second photoresist film 8.

Next, in the step shown in FIG. 8, wavelength = 130Å is formed on the second photoresist film 8 obtained in the step shown in FIG.
The reduced projection exposure using the X-ray 3 is performed to form the exposure unit 4. The reduction projection exposure can sufficiently resolve a width of 0.05 μm. Next, in a step shown in FIG. 9, the exposed portion 4 obtained in the step shown in FIG. 8 is selectively removed, and a fine pattern made of the second photoresist film 8 is formed on the first photoresist film 12. To form. This fine pattern serves as a mask for equal-magnification projection exposure that will be performed in a later step. Since this mask is formed by patterning by reduction projection exposure, it has extremely high accuracy.

Next, in the step shown in FIG. 10, the second photoresist film 8 obtained in the step shown in FIG.
The same-magnification projection exposure using 80 Å X-ray 7 is performed. At this time,
For example, the long wavelength side of the absorption edge of C is used with a width of about 10Å. Here, since the X-ray 7 having the wavelength of 44 to 80 Å is absorbed by the X-ray absorber contained in the second photoresist film 8, the area other than the area of the second photoresist film 8 is exposed. It will be Part 4. By doing so, the fine pattern can be accurately transferred in the depth direction of the first photoresist film 12.

Next, in the step shown in FIG. 11, the exposed portion 4 obtained in the step shown in FIG. 10 is selectively removed, so that the support 1 has a required film thickness and a highly accurate pattern. The transferred photoresist pattern is formed. Although a positive type photoresist is used in this embodiment, a negative type photoresist film may be used. (Third Embodiment) Next, a third embodiment according to the present invention will be described with reference to the drawings.

12 to 16 show a third embodiment of the present invention.
FIG. 6 is a process chart showing a photolithography method using X-rays according to the present invention. In the step shown in FIG. 12, X is formed on the support 1.
The thickness of the first photoresist film 12 that is exposed to the line is
It is formed with a thickness of about 1.0 μm. In this embodiment, as the first photoresist film 12, a positive type “SAL601-ER made of novolac resin and excellent in dry etching resistance is used.
7 (trade name), manufactured by Shipley Co., Ltd. was used. Next, X made of AuSi is formed on the first photoresist film 12.
The line absorber layer 13 is formed with a film thickness of about 0.1 μm.
Then, a second photoresist film 14 which is exposed to X-rays is formed on the X-ray absorber layer 13 with a film thickness of about 0.3 μm. In this embodiment, the second photoresist film 14
"PMMA (trade name)" was used as

Next, in the step shown in FIG. 13, a wavelength = 1 is formed on the second photoresist film 14 obtained in the step shown in FIG.
Reduction projection exposure using 10 Å X-ray 3 is performed, and exposure unit 4
To form. The reduction projection exposure can sufficiently resolve a width of 0.05 μm. Next, in the step shown in FIG. 14, the exposed portion 4 obtained in the step shown in FIG. 13 is selectively removed. Next, using the second photoresist film 14 after the selective removal as a mask, the X-ray absorber layer 13 is covered with ClF ₃ ,
Gas assisted reactive sputter etching is performed using Ar gas to selectively remove the X-ray absorber layer 13.

Next, in the step shown in FIG. 15, the second photoresist film 14 obtained in the step shown in FIG. 14 is removed, and the X-ray absorber layer 13 is formed on the first photoresist film 12. Form a fine pattern. This fine pattern serves as a mask for equal-magnification projection exposure that will be performed in a later step. Since this mask is formed by patterning by reduction projection exposure, it has extremely high accuracy. Next, using the X-ray absorber layer 13 as a mask, the first photoresist film 12 is subjected to equal-magnification projection exposure using X-rays 7 having a wavelength of 44 to 80Å. At this time, for example, the long wavelength side of the absorption edge of C is used with a width of about 10Å. Here, the wavelength = 44 to 8
Since 0 Å X-rays 7 are absorbed by Au contained in the X-ray absorber layer 13, the exposed portion 4 is other than the region of the X-ray absorber layer 13 concerned. By doing this, the first
The fine pattern can be accurately transferred in the depth direction of the photoresist film 12.

Next, in the step shown in FIG. 16, the exposed portion 4 obtained in the step shown in FIG. 15 is selectively removed, and a highly precise pattern is formed on the support 1 while having a required film thickness. The transferred photoresist pattern is formed. Although a positive type photoresist is used in this embodiment, a negative type photoresist film may be used.

In the step shown in FIG. 12, the X-ray absorber layer 13 made of AuSi is formed with a film thickness of about 0.1 μm. Therefore, in the step shown in FIG. 15, X-rays with a wavelength of 50 to 80Å are used. I did the same size projection exposure, but not limited to this,
An X-ray absorber layer made of Au may be formed to have a film thickness of about 0.5 μm, and 1 × projection exposure using X-rays having a wavelength of 4 to 10 liters may be performed.

Further, in the process shown in FIG. 14, ClF ₃ and Ar gas were used for the X-ray absorber layer to perform gas-assisted reactive sputter etching. However, the present invention is not limited to this.
Etching may be performed under other conditions such as using other fluorine-based gas or chlorine-based gas instead of ClF ₃ . (Fourth Embodiment) Next, a fourth embodiment according to the present invention will be described with reference to the drawings.

17 to 23 show a fourth embodiment of the present invention.
FIG. 6 is a process chart showing a photolithography method using X-rays according to the present invention. In the step shown in FIG. 17, X is formed on the support 1.
A first positive photoresist film 6 that is sensitive to lines is formed with a film thickness of about 1.0 μm. In this embodiment, the first
Positive photoresist film 12 made of novolac resin excellent in dry etching resistance, "SAL601-ER
7 (trade name), manufactured by Shipley Co., Ltd. was used. Then, on the first positive photoresist film 6, a second positive photoresist film 15 having a higher sensitivity than the first positive photoresist film 6 and sensitive to X-rays is formed. 0.3μ
It is formed in about m. In this embodiment, “SAL603 (trade name), manufactured by Shipley Co.” is used as the second positive photoresist film 14.

Then, in the step shown in FIG. 18, the second positive photoresist film 15 obtained in the step shown in FIG.
Reduced projection exposure using X-ray 3 with wavelength = 130Å
The exposed portion 4 is formed. In the reduction projection exposure, 0.05
It can be fully resolved up to the width of μm. Next, in the step shown in FIG. 19, the exposed portion 4 obtained in the step shown in FIG. 18 is selectively removed. Then, the second positive photoresist film 1 is formed.
5 and the exposed first positive type photoresist film 6 are subjected to the whole surface exposure using the X-ray having the same wavelength as the reduction projection exposure. Here, the second positive photoresist film 15
Is more sensitive than the first positive photoresist film 6 and is therefore completely exposed.

Next, in the step shown in FIG. 20, on the upper surfaces of the first positive type photoresist film 6 and the second positive type photoresist film 13 which are entirely exposed in the step shown in FIG.
Au is deposited by sputtering, film thickness = 0.1
The X-ray absorber layer 13 having a thickness of about 0.2 μm is formed. Here, the X-ray absorber layer 13 is formed to have a film thickness smaller than that of the second positive photoresist film 15.

Next, in the step shown in FIG. 21, the process shown in FIG.
In the first positive photoresist film 6 and the second positive photoresist film 15 which are entirely exposed in the step shown in (1), a desired developing solution (for example, "NMD-3 (manufactured by Tokyo Ohka)")
Wet etching is performed by using. At this time, since the side wall of the second positive photoresist film 5 is exposed, the developing solution penetrates into this portion, but the first positive photoresist film 6 absorbs X-rays. Body layer 13
Serves as a mask, so that the developer is unlikely to enter. In addition, the second positive photoresist film 15 has higher sensitivity than the first positive photoresist film 6, and thus is more easily developed. Therefore, only the second positive photoresist film 15 is lifted off. In this way
The X-ray absorber layer 1 is formed on the first positive photoresist film 6.
A fine pattern consisting of 3 is formed. This fine pattern serves as a mask for 1 × projection exposure performed in a later step.
Since this mask is patterned by reduction projection exposure, it has extremely high precision.

Then, in the step shown in FIG. 22, the X-ray absorber layer 13 obtained in the step shown in FIG. 21 is used as a mask to form a wavelength = 44 to 80 on the first positive photoresist film 6.
The same-magnification projection exposure using the X-ray 7 of Å is performed. At this time, for example, the long wavelength side of the absorption edge of C is used with a width of about 10Å.
Here, since the X-rays 7 having the wavelength = 44 to 80Å are absorbed by the X-ray absorber layer 13, the X-ray absorber layer 13 is absorbed.
Except for the region, the exposed portion 4 is formed, and the fine pattern can be accurately transferred in the depth direction of the first positive photoresist film 6.

Next, in the step shown in FIG. 23, the exposed portion 4 obtained in the step shown in FIG. 22 is selectively removed, and a highly precise pattern having a required film thickness is formed on the support 1. The transferred photoresist pattern is formed. In this example, since the X-ray absorber layer 13 made of Au was formed to a film thickness of about 0.1 μm in the process shown in FIG.
In the step shown in FIG. 2, the same-magnification projection exposure using X-rays having a wavelength of 44 to 80 Å was performed, and the film thickness of the X-ray absorber layer 13 =
If it is formed to have a thickness of about 0.5 μm, it is possible to perform equal-magnification projection exposure using X-rays having a wavelength of 4 to 10 Å, preferably 6 to 10 Å, and transfer accuracy is further improved. (Fifth Embodiment) Next, a fifth embodiment according to the present invention will be described with reference to the drawings.

24 to 29 show a fifth embodiment of the present invention.
FIG. 6 is a process chart showing a photolithography method using X-rays according to the present invention. In the step shown in FIG. 24, X is formed on the support 1.
The thickness of the positive type photoresist film 16 which is exposed to a line is
It is formed with a thickness of about 1.3 μm. In this embodiment, “SAL603 (trade name), manufactured by Shipley” is used as the positive type photoresist film 12.

Then, in the step shown in FIG. 25, the positive photoresist film 16 obtained in the step shown in FIG.
Reduced projection exposure using X-ray 3 of 130 Å is performed. In this reduction projection exposure, the upper layer 0.3 μm of the positive photoresist film 16 is exposed, and this portion becomes the exposed portion 4.
Furthermore, in the reduction projection exposure, it is possible to sufficiently resolve up to a width of 0.05 μm.

Next, in the step shown in FIG. 26, after the exposed portion 4 obtained in the step shown in FIG. 25 is selectively removed, an X-ray having the same wavelength as that in the reduction projection exposure is formed on the positive photoresist film 16. The entire surface is exposed using lines. Next, in the step shown in FIG. 27, Au is deposited by sputtering on the upper surface of the positive photoresist film 16 which has been subjected to the entire surface exposure in the step shown in FIG. 26, and the film thickness is about 0.1 to 0.2 μm. The X-ray absorber layer 13 is formed. Here, the X-ray absorber layer 13
Is formed so as to have a film thickness smaller than the gap formed on the surface of the positive photoresist film 16 after the selective removal.

Next, in the step shown in FIG.
Positive type photoresist film 1 which is entirely exposed in the step shown in FIG.
6 is wet-etched using a desired developing solution (for example, “NMD-3, (manufactured by Tokyo Ohka)”). At this time, since the side wall of the convex portion (the unexposed portion in the reduction projection exposure) of the positive photoresist film 16 is exposed, the developing solution penetrates into this portion, but the concave portion is exposed by the X-ray. Since the absorber layer 13 serves as a mask, it is difficult for the developer to enter. Therefore, only the convex portion is lifted off. In this way, a fine pattern made of the X-ray absorber layer 13 is formed on the positive photoresist film 16. This fine pattern serves as a mask for equal-magnification projection exposure that will be performed in a later step. Since this mask is patterned by reduction projection exposure, it has extremely high precision. Then, using the X-ray absorber layer 13 as a mask, the first
The positive type photoresist film 6 is subjected to equal-magnification projection exposure using X-ray 7 having a wavelength of 44 to 80Å. At this time, for example,
The long wavelength side of the absorption edge of C is used with a width of about 10Å. Here, since the X-rays 7 having the wavelength of 44 to 80 Å are absorbed by the X-ray absorber layer 13, the portions other than the region of the X-ray absorber layer 13 become the exposure section 4, and the first positive type photo The fine pattern can be accurately transferred in the depth direction of the resist film 6.

Next, in the step shown in FIG. 29, the exposed portion 4 obtained in the step shown in FIG. 28 is selectively removed, and a highly precise pattern having a required film thickness is formed on the support 1. The transferred photoresist pattern is formed. In this example, since the X-ray absorber layer 13 made of Au was formed to a film thickness of about 0.1 μm in the step shown in FIG.
In the step shown in FIG. 8, the same-magnification projection exposure using X-rays having a wavelength of 44 to 80 Å was performed.
If it is formed to have a thickness of about 0.5 μm, it is possible to perform equal-magnification projection exposure using X-rays having a wavelength of 4 to 10 Å, preferably 6 to 10 Å, and transfer accuracy is further improved.

In the first to fifth embodiments, the SOR is used as the light source, but the light source is not limited to this, and other light sources may be used if desired. Further, although the Mo / Si multilayer film is used as the mask for reduction projection exposure, the mask is not limited to this, and an Au / C multilayer film or the like may be used. Then, in Examples 1 to 5, the wavelength of X-rays may be determined by the photoresist film used, and a desired X-ray absorber such as Si, Au, Re or the like may be used depending on the wavelength. You can do it.

[0053]

As described above, according to the first aspect of the present invention, reduction projection exposure using X-rays is selectively performed on the photoresist film, and the reduction projection exposure is performed on the upper layer portion of the photoresist film. By patterning the mask for equal-magnification projection exposure using X-rays performed in the step of 1, it is possible to form an extremely accurate mask that is sufficiently adaptable to the equal-magnification projection exposure. Further, the mask pattern can be transferred extremely accurately in the depth direction of the photoresist film by the equal-magnification projection exposure. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be supplemented with each other. Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

According to the second aspect of the invention, the second photoresist film formed on the first photoresist film is selectively subjected to reduction projection exposure using X-rays, By patterning a mask for 1 × projection exposure using X-rays performed in a later step on the first photoresist film, it is possible to sufficiently adapt to the 1 × projection exposure,
An extremely accurate mask can be formed. Further, the mask pattern can be transferred with high accuracy in the depth direction of the first photoresist film by the same-magnification projection exposure. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be supplemented with each other.
Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

Further, according to the invention of claim 3, after the first photoresist film, the X-ray absorber layer and the second photoresist film are sequentially formed, the second photoresist film is formed. By selectively performing reduction projection exposure using X-rays on the film, and patterning a mask for equal-magnification projection exposure using X-rays performed in a later step on the first photoresist film, It is possible to form an extremely accurate mask that is sufficiently adaptable to the same-magnification projection exposure. Further, the mask pattern can be transferred with high accuracy in the depth direction of the first photoresist film by the same-magnification projection exposure. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be supplemented with each other. Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, it is possible to easily obtain a photoresist pattern having a required film thickness and having a highly accurate pattern transferred.

According to the fourth aspect of the present invention, a second positive film, which is more sensitive than the first positive photoresist film and more sensitive to X-rays, is formed on the first positive photoresist film. After forming the positive photoresist film, the second positive photoresist film is selectively subjected to reduction projection exposure using X-rays, and then the first positive photoresist film is subjected to a reduction projection exposure in a later step. By patterning the mask for the same-magnification projection exposure using X-rays to be performed, it is possible to form an extremely accurate mask that is sufficiently adaptable to the same-magnification projection exposure. In addition, by the above-mentioned 1 × projection exposure,
The mask pattern can be transferred extremely accurately in the depth direction of the positive type photoresist film. Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be supplemented with each other. Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, a photoresist pattern having a required film thickness and having a highly accurate pattern transferred,
Easy to get.

Further, according to the invention of claim 5, a reduction projection exposure using X-rays is selectively performed on the positive type photoresist film, whereby the positive type photoresist film is formed on the positive type photoresist film. By patterning a mask for 1 × projection exposure using X-rays performed in a later step, it is possible to form an extremely accurate mask that is sufficiently adaptable to the 1 × projection exposure. Further, the mask pattern can be transferred with extremely high precision in the depth direction of the positive photoresist film by the equal-magnification projection exposure.
Therefore, the drawbacks of the reduction projection exposure and the unit-magnification projection exposure can be supplemented with each other. Further, since the mask for 1 × projection exposure can be directly formed on the photoresist film, the resolution of 1 × projection exposure can be further improved. As a result, while having the required film thickness,
A photoresist pattern to which a highly accurate pattern is transferred can be easily obtained.

[Brief description of drawings]

FIG. 1 is a process diagram showing a photolithography method using X-rays according to a first embodiment of the present invention.

FIG. 2 is a process drawing showing the photolithography method using X-rays according to the first embodiment of the present invention.

FIG. 3 is a process drawing showing the photolithography method using X-rays according to the first embodiment of the present invention.

FIG. 4 is a process drawing showing the photolithography method using X-rays according to the first embodiment of the present invention.

FIG. 5 is a process drawing showing the photolithography method using X-rays according to the first embodiment of the present invention.

FIG. 6 is a process drawing showing the photolithography method using X-rays according to the first embodiment of the present invention.

FIG. 7 is a process drawing showing the photolithography method using X-rays according to the second embodiment of the present invention.

FIG. 8 is a process drawing showing the photolithography method using X-rays according to the second embodiment of the present invention.

FIG. 9 is a process drawing showing the photolithography method using X-rays according to the second embodiment of the present invention.

FIG. 10 is a process chart showing the photolithography method using X-rays according to the second embodiment of the present invention.

FIG. 11 is a process drawing showing the photolithography method using X-rays according to the second embodiment of the present invention.

FIG. 12 is a process drawing showing the photolithography method using X-rays according to the third embodiment of the present invention.

FIG. 13 is a process drawing showing the photolithography method using X-rays according to the third embodiment of the present invention.

FIG. 14 is a process drawing showing the photolithography method using X-rays according to the third embodiment of the present invention.

FIG. 15 is a process drawing showing the photolithography method using X-rays according to the third embodiment of the present invention.

FIG. 16 is a process drawing showing the photolithography method using X-rays according to the third embodiment of the present invention.

FIG. 17 is a process chart showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 18 is a process chart showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 19 is a process drawing showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 20 is a process drawing showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 21 is a process drawing showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 22 is a process chart showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 23 is a process chart showing the photolithography method using X-rays according to the fourth embodiment of the present invention.

FIG. 24 is a process drawing showing the photolithography method using X-rays according to the fifth embodiment of the present invention.

FIG. 25 is a process chart showing the photolithography method using X-rays according to the fifth embodiment of the present invention.

FIG. 26 is a process drawing showing the photolithography method using X-rays according to the fifth embodiment of the present invention.

FIG. 27 is a process chart showing the photolithography method using X-rays according to the fifth embodiment of the present invention.

FIG. 28 is a process drawing showing the photolithography method using X-rays according to the fifth embodiment of the present invention.

FIG. 29 is a process drawing showing the photolithography method using X-rays according to the fifth embodiment of the present invention.

[Explanation of symbols]

 1 Support 2 Photoresist film 3 X-ray 4 Exposed part 5 Photoresist film in which X-ray absorber is diffused 6 First positive photoresist film 7 X-ray 8 Second photoresist film 12 First photoresist Film 13 X-ray absorber layer 14 Second photoresist film 15 Second positive photoresist film 16 Positive photoresist film

Claims (5)

[Claims] 1. A photoresist film coated on a support,
In a photolithography method using X-rays, which transfers a desired pattern using X-rays, a first step of forming a photoresist film that is sensitive to X-rays on the support, and X-rays on the photoresist film. A second step of selectively performing reduction projection exposure using the above to form an image portion and a non-image portion, and a third step of selectively diffusing an X-ray absorber into the image portion of the photoresist film, A fourth step of selectively removing the non-image portion of the photoresist film, and using the photoresist film having the X-ray absorber diffused in the photoresist film after the selective removal as a mask,
And a fifth step of performing equal-magnification projection exposure using X-rays of a wavelength absorbed by the X-ray absorber, the photolithography method using X-rays. 2. A photoresist film coated on a support,
In a photolithography method using X-rays, which transfers a desired pattern using X-rays, a first step of forming a first photoresist film that is exposed to X-rays on the support, and the first photolithography method. A second step of forming a second photoresist film on the resist film, the second photoresist film containing an X-ray absorber and being exposed to X-rays of a wavelength which is absorbed by the X-ray absorber in a small amount; A second step of selectively performing reduced projection exposure on the photoresist film using X-rays of a wavelength that is absorbed by the X-ray absorber to form an image portion and a non-image portion; Third step of selectively removing the non-image part of the photoresist film, and the X-ray absorber using the second photoresist film after the selective removal as a mask on the first photoresist film. Demagnification projection dew using absorbed X-rays A photolithography method using X-rays, which comprises a fourth step of applying light. 3. A photoresist film coated on a support,
In a photolithography method using X-rays, which transfers a desired pattern using X-rays, a first step of forming a first photoresist film that is exposed to X-rays on the support, and the first photolithography method. A second step of forming an X-ray absorber layer on the resist film, a third step of forming a second photoresist film that is sensitive to X-rays on the X-ray absorber layer, and the second step. For photoresist film,
A fourth step of selectively performing reduced projection exposure using X-rays to form an image portion and a non-image portion, and a fifth step of selectively removing the non-image portion of the second photoresist film, Using the second photoresist film after the selective removal as a mask, the X-ray absorber layer is selectively removed, and then the second photoresist film is removed.
The sixth step of removing the photoresist film, and using the X-ray absorber layer after the selective removal as a mask, the first photoresist film is exposed to X-rays having a wavelength absorbed by the X-ray absorber layer. A seventh step of performing the same-magnification projection exposure used, and a photolithography method using X-rays. 4. A photoresist film coated on a support,
In a photolithography method using X-rays, which transfers a desired pattern using X-rays, a first step of forming a first positive photoresist film that is exposed to X-rays on the support, On the positive photoresist film of 1.
Higher sensitivity than that of the first positive photoresist film and X
A second step of forming a second positive photoresist film which is exposed to a line, and X on the second positive photoresist film.
Third step of selectively performing reduced projection exposure using a line, a fourth step of selectively removing the exposed portion of the second positive photoresist film, and a second positive step after the selective removal. Type photoresist film and the first positive type photoresist film exposed by the selective removal are subjected to a whole surface exposure using X-rays having the same wavelength as the reduction projection exposure, and a fifth step after the whole surface exposure A sixth step of forming an X-ray absorber layer on the upper surfaces of both the positive photoresist films with a film thickness smaller than that of the second positive photoresist film; and the second positive photoresist film and the upper surface thereof. A seventh step of selectively removing the X-ray absorber layer formed on the first positive photoresist film by using the X-ray absorber layer after the selective removal as a mask. Single-magnification projection exposure using X-rays of a wavelength absorbed in the body layer Photolithographic method using the X-ray, characterized in that it comprises an eighth step, the performing. 5. A photoresist film coated on a support,
In a photolithography method using X-rays, which transfers a desired pattern using X-rays, a first step of forming a positive photoresist film that is exposed to X-rays on the support, and the positive photoresist A second step of selectively performing reduction projection exposure using X-rays on the film; a third step of selectively removing an exposed portion of the positive photoresist film; and a positive photoresist after the selective removal. A fourth step of subjecting the resist film to an overall exposure using X-rays of the same wavelength as the reduction projection exposure, and the positive photoresist after the selective removal on the upper surface of the positive photoresist film after the overall exposure. A fifth step of forming an X-ray absorber layer with a film thickness smaller than the gap generated in the film, and a sixth step of selectively removing the positive photoresist film on which the X-ray absorber layer is formed. X-ray absorption after the selective removal A seventh step of subjecting the positive photoresist film to equal-magnification projection exposure using X-rays of a wavelength absorbed by the X-ray absorber layer, using the body layer as a mask. Photolithography method using lines.