KR20100019703A - Euv photo mask and manufacturing method of the same - Google Patents

Abstract

EUV exposure mask of the present invention is characterized in that it comprises an absorbing layer pattern formed on the transparent substrate and a reflective layer embedded between the absorbing layer pattern.

In addition, the manufacturing method of the EUV exposure mask of the present invention is characterized in that it comprises the step of forming an absorbing layer pattern on the transparent substrate and filling the reflective layer between the absorbing layer pattern.

In addition, the method of forming a semiconductor device of the present invention includes 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 above-described EUV exposure mask, and the photoresist film. And forming a photoresist pattern by performing a developing process on the substrate, and etching the etched layer by using the photoresist pattern as an etching mask.

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 EUV has high energy in a short wavelength band, when light is incident on the exposure mask and the lens, most of the light is absorbed by the absorbing layer of the mask and disappears.

Accordingly, 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 by a reflection device such as a reflection mirror is used.

Since the exposure process using the extreme ultraviolet ray uses the method of using the reflected light as described above, it has a constant angle of incidence without incident light perpendicular to the exposure mask, and the light incident at such an angle is reflected by the reflective layer of the exposure mask. It is reflected or absorbed by the absorbing layer of the exposure mask.

1A to 1C are cross-sectional views illustrating a method of manufacturing an exposure mask according to the prior art.

As shown in FIG. 1A, 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. 1B, a photoresist film (not shown) is formed on the absorber layer 16, and then the photoresist pattern 18 is formed by patterning the photoresist into a shape to be formed on the wafer using a mask.

1C, 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. .

2 is a view showing an exposure process using an exposure mask according to the prior art.

As shown in FIG. 2, when patterning using an exposure mask including a mask pattern formed by a mask manufacturing method according to the related art, the light source is obliquely incident to the exposure mask and has a predetermined angle. Obliquely tilted and reflected.

That is, among the light sources incident on the exposure mask, the light source reflected by the reflective layer 12, such as 'A', is exposed onto the wafer to pattern the photosensitive film applied on the wafer, and absorbed by the absorption layer pattern 20 as 'B'. Since the light source to be reached does not reach the photoresist applied on the wafer, the photoresist cannot be patterned.

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 has a problem of distorting the pattern by lowering the contrast of the pattern when patterning the light source reflected on the exposure mask.

In the present invention, to solve the problem that the light reflected from the reflective layer of the EUV exposure mask is absorbed back to the absorbing layer.

EUV exposure mask of the present invention

An absorption layer pattern formed on the transparent substrate;

It characterized in that it comprises a reflective layer embedded between the absorbing layer pattern.

In this case, the reflective layer is characterized in that it comprises a photonic crystal.

In addition, the photonic crystal is characterized in that the colloidal (colloidal) state.

At this time, the colloidal photonic crystal is characterized in that it comprises a photonic crystal formed in the structure of the face-centered cube by spontaneous sedimentation of particles dispersed in a solvent.

The photonic crystal in the colloidal state is characterized in that it comprises a photonic crystal crystallized using the electrostatic repulsive force of the particles having a surface charge.

The photonic crystal in the colloidal state may include photonic crystals formed by self-assembly in a physically limited space.

EUV exposure mask forming method of the present invention

Forming an absorption layer pattern on the transparent substrate; and

And embedding a reflective layer between the absorbing layer patterns.

In this case, the reflective layer is characterized in that it comprises a photonic crystal.

At this time, the absorption layer pattern is

Forming an absorbing layer on the transparent substrate;

Forming a photoresist pattern on the absorber layer;

And etching the absorber layer using the photoresist pattern as an etching mask.

And, the absorbing layer is characterized in that it comprises chromium.

The method of forming a semiconductor device of the present invention

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

Performing an exposure process using EUV on the photosensitive film by using the above-described EUV exposure mask;

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

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

In the present invention, the light reflected from the reflective layer of the EUV exposure mask is prevented from being absorbed by the absorbing layer, thereby improving the contrast ratio, thereby preventing the pattern size change due to the deformation of the pattern.

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

3 illustrates an exposure mask according to the present invention, and includes an absorption layer pattern 34 formed on the transparent substrate 30 and a photonic crystal 40 embedded therebetween.

In this case, since the photonic crystal 40 serves as a reflective layer, the photonic crystal 40 is patterned on the wafer using a light source reflected by the photonic crystal 40.

Here, photonic crystals refer to artificial crystals in which dielectrics are arranged periodically.

As described above, materials having a crystal structure have a periodic potential due to the regular arrangement of atoms or molecules constituting the material, thereby affecting the movement of electrons, thereby forming a band gap.

The photonic crystal in which the bandgap is formed has the property of not transmitting light but reflecting it, and using this principle, it acts as a reflective layer in the exposure mask.

At this time, the photonic crystal is deposited on the exposure mask in a colloidal state.

For reference, the colloidal photonic crystal may be manufactured by a general method, which may be manufactured by one of the following methods.

The method for producing colloidal photonic crystals is a method of forming a surface-centered cube by spontaneous sedimentation of particles dispersed in a solvent, crystallization using electrostatic repulsive force using particles having surface charges, or physically limited space. One of the methods of self-assembly can be used.

The method of forming the EUV exposure mask using the colloidal photonic crystal formed as described above will be described with reference to FIGS. 4A to 4C.

As shown in FIG. 4A, an absorbing layer 32 that absorbs light is formed on the transparent substrate 40.

At this time, the absorption layer 32 is preferably formed by depositing chromium.

Then, as shown in FIG. 4B, an absorbing layer pattern 34 is formed on the wafer to be patterned into a desired shape.

The absorber layer pattern 34 is formed through a photolithography process after applying a photoresist film (not shown) on the absorber layer 34.

4C, the colloidal photonic crystal 40 is embedded in the portion where the absorber layer is removed by a photolithography process.

In this case, the photonic crystal 40 serves as a mask pattern to reflect the incident light source and to be exposed on the wafer, thereby exposing and patterning the photosensitive film coated on the wafer.

As such, the colloidal photonic crystal 40 is formed to fill the gap between the absorption layer patterns 34 formed on the transparent substrate 30 so that the light is absorbed in the absorption layer pattern 34, and the light is reflected by the photonic crystal 40. Be sure to

Accordingly, the shadow effect can be prevented by preventing the light reflected by the reflective layer of the conventional exposure mask from being absorbed again by the absorbing layer pattern.

5A to 5C 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. 5A, a photosensitive film 52 is coated on the semiconductor substrate 50 on which an etched layer (not shown) is formed.

Then, as shown in Figure 5b, the exposure process is performed using the EUV exposure mask of the present invention.

At this time, the light 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.

Of the light sources incident on the exposure mask, the light source 'D' incident on the photonic crystal 40 is reflected by the photonic crystal 40 so that it is exposed on the wafer to expose the photoresist film 52 coated on the semiconductor substrate 50. The light source 'E' incident on the absorbing layer pattern 34 is absorbed by the absorbing layer pattern 34 and is not exposed to the photosensitive film 52.

5C, a development process is performed on the photoresist 52 to form the photoresist pattern 54.

That is, the photosensitive film pattern 54 is formed by not being developed because it is not exposed due to the exposure source absorbed by the absorption layer pattern 34.

Subsequently, the etched layer (not shown) is etched using the photoresist pattern 54 as an etch mask to form a semiconductor device.

The EUV exposure mask of the present invention prevents light reflected from the conventional reflective layer from being absorbed by the absorbing layer pattern once again by embedding the photonic crystal 40 between the absorbing layer patterns 34 to eliminate the shadow effect, thereby reducing the photosensitive film pattern 54. The pattern formed on the exposure mask is reflected without distortion, so that a desired pattern can be formed.

1A to 1C are cross-sectional views illustrating a method of manufacturing an exposure mask according to the prior art.

2 is a view showing an exposure process using an exposure mask according to the prior art.

3 is an exposure mask according to the present invention.

4A to 4C are cross-sectional views illustrating a method of manufacturing an exposure mask according to the present invention.

5A to 5C are schematic views showing a method of forming a semiconductor device using the exposure mask of the present invention.

Claims (12)

An absorption layer pattern formed on the transparent substrate; And EUV exposure mask comprising a reflective layer embedded between the absorbing layer pattern. The method of claim 1, EUV exposure mask, characterized in that the reflective layer comprises a photonic crystal. 3. The method of claim 2, The photonic crystal EUV exposure mask, characterized in that the colloidal (colloidal) state. The method of claim 3, The photonic crystal in the colloidal state EUV exposure mask, characterized in that the particles dispersed in the solvent formed by a surface settled cube structure by natural sedimentation. The method of claim 3, The colloidal photonic crystal is EUV exposure mask, characterized in that crystallized using the electrostatic repulsive force of the particles having a surface charge. 4. The EUV exposure mask of claim 3, wherein the photonic crystal in the colloidal state is formed by self-assembly in a physically limited space. Forming an absorption layer pattern on the transparent substrate; and And embedding a reflective layer between the absorbing layer patterns. The method of claim 7, wherein And the reflective layer comprises photonic crystals. The method of claim 7, wherein Forming the absorbing layer pattern is Forming an absorbing layer on the transparent substrate; Forming a photoresist pattern on the absorber layer; And And etching the absorbing layer using the photoresist pattern as an etching mask. The method of claim 8, And the absorber layer comprises chromium. 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. The method of claim 11, And the photosensitive film pattern is formed by exposing the light source reflected by the photonic crystals of the EUV exposure mask of claim 1 to the photosensitive film and then developing the semiconductor device.

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