KR20100019706A

KR20100019706A - Euv photo mask and manufacturing method of the same

Info

Publication number: KR20100019706A
Application number: KR1020080078399A
Authority: KR
Inventors: 김영식
Original assignee: 주식회사 하이닉스반도체
Priority date: 2008-08-11
Filing date: 2008-08-11
Publication date: 2010-02-19

Abstract

PURPOSE: An EUV(extreme ultraviolet radiation) photo mask and a manufacturing method of the same are provided to prevent a shading effect by forming a highly reflective pattern on a sidewall of a absorber pattern. CONSTITUTION: A reflecting layer(110) is formed in upper part a mask substrate. The absorber pattern(130) is formed on upper part of the reflection layer. The highly reflective pattern is formed on the reflecting layer and a absorber patten side wall. The highly reflective pattern(145) is formed with the material same as the reflection layer pattern. The reflecting layer comprises a laminating structure of multilayer.

Description

EV exposure mask and its formation method {EUV photo mask and manufacturing method of the same}

The present invention relates to an EUV exposure mask and a method of forming the same, and more particularly, to prevent shadow effects.

As the design rule of the semiconductor device is reduced, the line width of the semiconductor device is also reduced, and the wavelength of the exposure source is also reduced to realize this.

In the conventional exposure process, I-line, G-line, krF and ArF, etc. were used as the exposure source, but due to the high integration of semiconductor devices, patterning is difficult, and thus, ultraviolet ultraviolet radiation (EUV) having a shorter wavelength than the conventional exposure source is used. An exposure method using the above has been proposed.

In the conventional exposure method, a pattern is formed on a wafer using light transmitted through an exposure mask. The exposure process using extreme ultraviolet light uses high-energy light at a wavelength of 13.5 nm, so the conventional exposure method uses a wafer. You cannot form a pattern on it.

That is, since the exposure source has high energy in a short wavelength band, most of the light incident on the exposure mask and the lens from the exposure source is absorbed by the absorption layer of the mask and disappears, and thus cannot reach the wafer and form a pattern.

Therefore, in the exposure method using EUV, a reflection type system is required, and a method of forming a pattern on a wafer using light reflected through a reflection device such as a reflection mirror as shown in FIG. 1 is used.

Since the exposure process using extreme ultraviolet rays employs the method of using the reflected light as described above, the light incident from the exposure source has a constant angle of incidence that is not perpendicular to the exposure mask, and the obliquely incident light is a reflection layer of the exposure mask. Is reflected by or absorbed by the absorbing layer of the exposure mask.

2A to 2C are cross-sectional views illustrating a method of manufacturing an exposure mask according to the prior art.

As shown in FIG. 2A, a reflector 12, a buffer layer 14, and an absorber 16 that absorb light are formed on the transparent substrate 10. .

Next, as shown in FIG. 2B, a photoresist film is coated on the absorber layer 16 and then patterned into a desired shape to form the photoresist pattern 18.

2C, the absorber layer 16 and the buffer layer 14 are etched using the photoresist pattern 18 as an etch mask to form a buffer layer pattern 20 and an absorber layer pattern 22 serving as a mask pattern. .

3 is a view showing a path of light in the case of exposing using an exposure mask according to the prior art.

As shown in FIG. 3, when light is patterned using an exposure mask including a mask pattern formed by a mask manufacturing method according to the prior art, light is reflected at an angle to the exposure mask at an angle, and thus reflected light also has a predetermined angle. Obliquely tilted and reflected.

That is, the light reflected from the reflective layer 12, such as 'A', of the incident light incident on the exposure mask is exposed onto the wafer to pattern the photosensitive film applied on the wafer, and absorbed into the absorbing layer pattern 20, such as 'B'. The light which does not reach the photoresist applied on the wafer does not pattern the photoresist.

At this time, since the light such as 'C' is reflected by the reflective layer 12 but is obliquely reflected at a predetermined angle, the light passes through the absorption layer pattern 22 again, so that a portion that cannot be reflected and absorbed is not exposed to the wafer.

For this reason, it affects the shape of the pattern and causes pattern deformation. This is called a shadowing effect.

This shadow effect distorts the pattern by lowering the contrast of the pattern when patterning using the light reflected on the exposure mask.

4A is a schematic diagram showing patterning using a transmissive exposure mask, and FIG. 4B is a schematic diagram showing patterning using a reflective exposure mask.

In the case of using the transmissive exposure mask as shown in Fig. 4A, the incident light incident from the exposure source is patterned by passing through the exposure mask and reaching the wafer so that the pattern is formed at the same position as that of the mask pattern.

However, in the case of using the reflective exposure mask as shown in FIG. 4B, since the incident light incident from the exposure source is reflected by the exposure mask and is patterned by reaching the wafer, the light reflected from the reflective layer of the exposure mask is absorbed in the absorbing layer pattern. In this case, there is a limit in that the pattern is not formed at the same position as the mask pattern and shifted and patterned.

The EUV exposure mask and the method of forming a semiconductor device using the same of the present invention is to solve the problem that the light reflected from the reflective layer of the EUV exposure mask is absorbed back into the absorbing layer to generate a shadow effect.

The EUV exposure mask of the present invention is characterized in that it comprises a reflective layer formed on the mask substrate and the reflective layer formed on the reflective layer and the high reflective layer pattern formed on the sidewall of the reflective layer and the absorbing layer pattern.

In this case, the high reflection layer pattern is formed of the same material as the reflective layer pattern.

In addition, the reflective layer is characterized in that it comprises a multilayer structure.

In this case, the multilayer stacking structure may include a structure in which two different layers are alternately stacked.

In addition, the two different layers may include a silicon film and a molybdenum film.

In addition, the capping layer is characterized in that it further comprises a reflective layer.

The buffer layer pattern may be further included on the capping layer.

The EUV exposure mask forming method of the present invention comprises the steps of forming a reflective layer on the mask substrate, and sequentially forming an absorbing layer pattern on the reflective layer, and forming a high reflective layer on the entire upper surface of the reflective layer and the absorbing layer pattern; And planarizing the high reflection layer to expose the absorber layer pattern, thereby forming a high reflection layer pattern.

In this case, the absorbing layer pattern is formed by etching the absorbing layer by forming an absorbing layer on the reflective layer and using the photoresist pattern formed on the absorbing layer as an etching mask.

The high reflection layer pattern is formed of the same material as the reflective layer pattern.

The method may further include forming a capping layer after the forming of the reflective layer.

The method may further include forming a buffer layer pattern after forming the capping layer.

The method of forming a semiconductor device of the present invention comprises the steps of applying a photoresist film on top of a semiconductor substrate on which an etched layer is formed, performing an exposure process using EUV on the photoresist film using the EUV exposure mask of claim 1 and Forming a photoresist pattern by performing a developing process, and etching the etched layer by using the photoresist pattern as an etching mask.

In the present invention, even when the EUV exposure mask is applied, there is an advantage of preventing the shadow effect to improve the yield of the pattern and shorten the process time.

Hereinafter, with reference to the accompanying drawings an embodiment of the present invention will be described in detail.

FIG. 5 illustrates an EUV exposure mask according to the present invention, wherein a reflective layer 110 formed on a mask substrate 100, a buffer layer pattern 120 and an absorption layer pattern 130 formed thereon, a reflective layer 110, and a buffer layer are formed on the mask substrate 100. It includes a high reflection layer pattern 145 formed on the side of the pattern 120 and the absorber layer pattern 130.

The high reflection layer pattern 145 is formed on the side of the buffer layer pattern 120 and the absorption layer pattern 130 and the reflective layer upper surface to prevent the light reflected from the reflective layer 110 from being absorbed by the absorption layer pattern 130 so that no shadow effect occurs. It plays a role of preventing.

In this case, the highly reflective layer pattern 145 is preferably made of the same layer as the reflective layer 110.

The buffer layer pattern 120 and the absorber layer pattern 130 absorb light when patterned from an exposure process using an EUV exposure mask, and the reflective layer 110 reflects light to be patterned on a wafer. It acts as a mask pattern.

In addition, the reflective layer 110 may be formed in a multilayered structure including a material capable of optimally reflecting light.

In this case, the multilayer stack structure includes a structure in which two different layers are alternately stacked, and the two layers include a silicon film and a molybdenum film.

In addition, a capping layer may be further formed between the reflective layer 110 and the buffer layer pattern 120 of the EUV exposure mask according to the present invention.

6A to 6C are cross-sectional views illustrating a method of forming an EUV exposure mask according to the present invention.

As shown in FIG. 6A, a reflective layer 110 reflecting light, a buffer layer pattern 120, and an absorbing layer pattern 130 absorbing light are formed on the transparent substrate 100.

For reference, an EUV exposure mask as shown in FIG. 6A may be formed through the following process.

After the photoresist is coated on the absorber layer, the photoresist layer is patterned into a desired shape, that is, a designed layout to form a photoresist pattern. The buffer layer pattern 120 and the absorber layer pattern 130 are etched by etching the absorber layer and the buffer layer using the photoresist pattern as an etch mask. Form.

6B, the high reflection layer 140 is deposited on the entire surface including the buffer layer pattern 120, the absorber layer pattern 130, and the reflective layer 110.

Next, as shown in FIG. 6C, the high reflection layer 140 formed on the absorption layer pattern 130 is etched to expose the absorption layer pattern 130.

In this case, chemical mechanical planarization (CMP) is most preferable by etching the high reflection layer 140.

As a result, the high reflection layer 140 on the upper portion of the absorption layer pattern 130 is etched by the planarization process to form the high reflection layer pattern 145 remaining only on the upper side of the reflective layer 110 and the sidewall of the absorption layer pattern 130.

Therefore, even when the absorber layer pattern 130 is exposed only to the upper portion and is incident toward the absorber layer pattern 130 formed above the reflective layer 110, the absorption layer pattern 130 is reflected by the high reflection layer pattern 145 formed on the sidewall thereof, thereby preventing the shadow effect. It will play a role.

7A to 7B are cross-sectional views illustrating a method of forming a semiconductor device using an EUV exposure mask of the present invention.

As shown in FIG. 7A, a photosensitive film 210 is coated on the semiconductor substrate 200 on which an etched layer (not shown) is formed.

Then, the exposure process is performed using the EUV exposure mask of the present invention.

In this case, the light incident from the exposure source is obliquely incident with an angle of incidence not perpendicular to the exposure mask, and thus the light reflected from the exposure mask is inclined.

Among the light incident to the exposure mask, light incident in the direction of the reflective layer 110, which is a mask pattern, is reflected and reaches the semiconductor substrate 200 to which the photosensitive film 210 is coated.

The light reflected by the reflective layer 210 but incident in the direction of the absorbing layer pattern 130 is reflected back by the high reflection layer pattern 145 to reach the wafer on which the photosensitive film 210 is coated.

The light source incident on the absorbing layer pattern 130 is absorbed by the absorbing layer pattern 130 and is not exposed to the photosensitive film 210.

Then, as illustrated in FIG. 7B, a development process is performed on the photoresist film 210 to form the photoresist pattern 220.

That is, incident light incident on the exposure mask from the exposure source through the above-described exposure process is reflected by the high reflection layer pattern 145 of the exposure mask, reaches the photosensitive film 210, is exposed, and is removed by the developing process to remove the photosensitive film. It is formed by patterning the photoresist pattern 220.

Subsequently, the etched layer (not shown) is etched using the photoresist pattern 220 as an etch mask to form a semiconductor device.

The EUV exposure mask of the present invention forms the high reflection layer pattern 145 on the sidewall of the absorption layer pattern 130 to prevent the light reflected from the conventional reflection layer from being absorbed by the absorption layer pattern once again.

Therefore, it is possible to form a desired pattern by reflecting without distortion in the form of the exposure mask pattern so that the shadow effect does not occur.

1 shows an exposure process employing a reflective system.

5 is a cross-sectional view showing an EUV exposure mask according to the present invention.

7A to 7B are cross-sectional views showing a method of forming a semiconductor device using an EUV exposure mask of the present invention.

Claims

A reflective layer formed on the mask substrate;

An absorption layer pattern formed on the reflective layer; And

And a highly reflective layer pattern formed on sidewalls of the reflective layer and the absorber layer pattern.

The method of claim 1,

The high reflective layer pattern is EUV exposure mask, characterized in that formed of the same material as the reflective layer pattern.

The method of claim 1,

EUV exposure mask, characterized in that the reflective layer comprises a multilayer structure.

The method of claim 3,

The multilayer stack structure includes an EUV exposure mask comprising a structure in which two different layers are alternately stacked.

The method of claim 4, wherein

Wherein said two different layers comprise a silicon film and a molybdenum film.

The method of claim 1,

EUV exposure mask further comprises a capping layer on the reflective layer.

The method of claim 6,

EUV exposure mask further comprises a buffer layer pattern on the capping layer.

Forming a reflective layer on the mask substrate;

Sequentially forming an absorbing layer pattern on the reflective layer;

Forming a high reflection layer on the entire upper surface of the reflective layer and the absorption layer pattern; And

Forming a high reflection layer pattern by planarizing the high reflection layer to expose the absorption layer pattern.

The method of claim 8,

The absorber layer pattern is

Forming an absorbing layer on the reflective layer; And

The method of forming an EUV exposure mask, wherein the absorption layer is formed by etching the photoresist pattern formed on the absorption layer as an etching mask.

The method of claim 8,

The method of forming an EUV exposure mask, characterized in that the high reflection layer pattern is formed of the same material as the reflective layer pattern.

The method of claim 8,

And forming a capping layer after the forming of the reflective layer.

The method of claim 11,

EUV exposure mask further comprises the step of forming a buffer layer pattern after forming the capping layer.

Applying a photosensitive film on top of the semiconductor substrate on which the etched layer is formed;

Performing an exposure process using EUV on the photosensitive film using the EUV exposure mask of claim 1;

Forming a photoresist pattern by performing a developing process on the photoresist; And

And etching the layer to be etched using the photoresist pattern as an etching mask.