KR101057197B1 - Phase reversal mask manufacturing method - Google Patents

Abstract

The method of manufacturing a phase shift mask according to the present invention includes forming pattern structures in which a phase shift pattern and a light shielding pattern are sequentially disposed on a transmissive substrate having a main pattern region and a frame region, and covering the pattern structures of the frame region. Forming a photoresist film pattern exposing the pattern structures of the main pattern area, and leaving the photoresist film pattern on the surface of the transmissive substrate where electrostatic damage may occur in the main pattern area; Removing the light blocking film pattern exposed in the main pattern region; and removing the photoresist film pattern.

Phase inversion mask, static electricity, developing process, electrostatic damage

Description

Method of fabricating phase shift mask

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a photomask, and more particularly, to a method of manufacturing a phase inversion mask for suppressing electrostatic damage.

In general, a semiconductor device is composed of various patterns. To form such patterns, a photolithography process is used. According to this photolithography process, a photoresist film whose solubility is changed by irradiation of light is formed on the pattern target film on the wafer, and after exposing a predetermined portion of the photoresist film using a photomask, the solubility of the developer is changed or Alternatively, the unchanged portion is removed to form a photoresist film pattern. The pattern target film exposed by the photoresist film pattern is removed by etching to form a pattern.

However, as the degree of integration of semiconductor devices increases, the size of patterns decreases. As a result, a pattern defect due to a decrease in resolution is emerging as a serious problem in forming a pattern using a photolithography process. Accordingly, various resolution enhancement techniques (RETs) are being developed to increase the resolution. One of them is a phase shift mask (PSM) instead of a conventional binary mask. ) To increase the resolution to minimize pattern defects.

1 and 2 are cross-sectional views illustrating an example of a method of manufacturing a phase inversion mask. First, as shown in FIG. 1, the pattern structure in which the phase inversion film pattern 120 and the light blocking film pattern 130 are sequentially disposed on the light transmissive substrate 110 having the main pattern area M and the frame area F is shown. Form. Typically, the phase inversion film pattern 120 is formed of a molybdenum silicon nitride (MoSiN) film, and the light blocking film pattern 130 is formed of a chromium (Cr) film. Next, as shown in FIG. 2, the photoresist film pattern 140 which selectively exposes the main pattern region M is formed. The photoresist film pattern 140 may be formed by forming a photoresist film on the entire photomask and performing ordinary exposure and development on the photoresist film. The light blocking layer pattern 130 exposed in the main pattern region M is removed by etching using the photoresist layer pattern 140 as an etching mask. However, a phenomenon in which the surface of the light transmissive substrate 110 is subjected to electrostatic damage during the exposure and development processes for forming the photoresist film pattern may occur.

3 is a view showing for explaining the electrostatic damage phenomenon of the light-transmitting region in the method of manufacturing the phase inversion mask of FIGS. Referring to FIG. 3, the main pattern region M has a length of, for example, several hundred μm to several thousand μm, and has a distance d1 of about 1.5 μm or less from another adjacent light blocking pattern 132 or the frame region F, for example. Alternatively, the light blocking film pattern 131 having d2) may exist. In this case, due to the static electricity generated by the friction with the developer in the process of forming the photoresist film pattern 140 that selectively exposes the main pattern region M while covering the frame region F, the arrows 151 in the drawing. Or 152, an electrostatic phenomenon in which electrons at the end of the light blocking film pattern 131 moves to another adjacent light blocking film pattern 132 or a light blocking film pattern (not shown) in the frame region F May occur and the transmissive substrate 110 exposed therebetween may be damaged. Damage of the light-transmitting substrate 100 due to the electrostatic damage may cause a defect in the exposure process for transferring the pattern on the wafer, and may be a major cause of the pattern transfer defect.

The problem to be solved by the present invention is to provide a method for manufacturing a phase shift mask to prevent the electrostatic damage of the light-transmitting substrate without changing the design parameters such as the profile or size of the patterns.

According to an aspect of the present invention, there is provided a method of fabricating a phase inversion mask, the method comprising: forming a pattern structure in which a phase inversion layer pattern and a light blocking layer pattern are sequentially disposed on a transmissive substrate having a main pattern region and a frame region, Forming a photoresist film pattern covering the pattern structures and exposing the pattern structures of the main pattern area, wherein the photoresist film pattern remains on the surface of the light-transmitting substrate where electrostatic damage may occur in the main pattern area; And removing the light blocking film pattern exposed in the main pattern region by the resist film pattern, and removing the photoresist film pattern.

In one example, the light blocking film pattern is formed using a chromium film.

In one example, the surface of the transmissive substrate in which the electrostatic damage may occur in the main pattern region may be a surface exposed between the light blocking layer pattern having a length of several hundred μm or more and another light blocking layer pattern disposed at an interval of 1.5 μm or less. have.

In one example, the surface of the light transmissive substrate in which the electrostatic damage may occur in the main pattern region may be a surface exposed between the light blocking layer pattern having a length of several hundred μm or more and the frame region disposed at intervals of 1.5 μm or less. .

According to the present invention, even if there is a light blocking film pattern which may cause electrostatic damage, the photoresist is exposed on the light-transmitting substrate exposed between adjacent light blocking film patterns or frame areas when forming the photoresist film pattern for removing the light blocking film pattern in the main pattern area. By allowing the film pattern to remain, a passage is formed through which electrons in the light blocking film pattern can move to another adjacent light blocking film pattern or frame region, thereby preventing the light-permeable substrate from receiving electrostatic damage without design adjustment such as changing the pattern profile. This is provided.

4 to 8 are diagrams for explaining a method of manufacturing a phase inversion mask according to an embodiment of the present invention.

First, as shown in FIG. 4, the phase inversion film 222 and the light blocking film 232 are sequentially formed on the light transmissive substrate 210 such as quartz. The light transmissive substrate 210 has a main pattern region M in which main patterns to be transferred are arranged and a frame region F surrounding the main pattern region M. FIG. In one example, the phase inversion film 222 is formed of a molybdenum silicon nitride (MoSiN) film, and the light blocking film 232 is formed of a chromium (Cr) film.

Next, as shown in FIG. 5, patterning is performed on the light blocking film (232 of FIG. 4) and the phase inversion film (222 of FIG. 4) to sequentially form the phase inversion film pattern 220 and the light blocking film pattern 230. Forming pattern structures 220/230 are formed. In more detail, a resist film pattern (not shown) is formed on the light blocking film 232 of FIG. 4. The resist film pattern exposes a part of the surface of the light blocking film 232 in the main pattern region M. FIG. The exposed portion of the light blocking film (232 of FIG. 4) is removed using the resist film pattern as an etch mask to form a light blocking film pattern 230 exposing a part of the surface of the phase inversion film (222 of FIG. 4). Subsequently, the exposed portion of the phase inversion film 222 is etched to form a phase inversion film pattern 220 exposing a part of the surface of the light transmitting substrate 210 of the main pattern region M. FIG. Then, the resist film pattern is removed.

The pattern structures 220/230 formed as described above are mostly in a constant shape, but in some cases, as shown in the drawing, a distance d3 or a frame of several hundred μm or more and adjacent to the other pattern structures 220/230 is adjacent. The pattern structure 220 / 230a may be 1.5 μm or less from the area d4. In this case, the exposed surfaces 211 and 212 of the translucent substrate 210 may be subjected to electrostatic damage in the subsequent process of forming the resist film pattern for removing the light blocking film patterns 230 and 230a in the main pattern region M. FIG. Therefore, in this embodiment, in order to prevent such electrostatic damage, the resist film pattern is formed so that the resist film pattern remains on the exposed surfaces 211 and 212.

In detail, as shown in FIG. 6, the phase inversion film pattern 220 and the light blocking film patterns 230 and 230a are sequentially disposed on the front surface of the light-transmitting substrate 210 having the pattern structures 220/230 and 220 / 230a. The resist film 240 is formed. The resist film 240 may be a photoresist film or may be an electron beam exposure resist film. Next, exposure to the reticle 250 or electron beam exposure is performed to change the solubility of a part of the resist film 240. For example, when the resist film 240 is used as a positive type, light or an electron beam (indicated by an arrow in the drawing) is irradiated to a portion to be removed through a subsequent development process. Therefore, since it is to expose the main pattern region M, the light or electron beam is not irradiated to the resist film 240 of the frame region F, while the resist pattern 240 of the main pattern region M is prevented. Light or electron beam is irradiated. In this case, the resist film 240 is also left on the exposed surface 211 of the light transmitting substrate 210 exposed between the pattern structures 220 / 230a and other adjacent pattern structures 220/230 to prevent damage from static electricity. For this purpose, no light or electron beam is irradiated to this part. Similarly, the resist film 240 remains on the exposed surface 212 of the transparent substrate 210 exposed between the pattern structure 220 / 230a and the adjacent frame region F. For this purpose, a light or electron beam Do not investigate.

Next, as shown in FIG. 7, a development process is performed on the resist film (240 of FIG. 6) subjected to exposure or electron beam exposure to form a resist film pattern 242. The resist film pattern 242 covers the light blocking film pattern 230 in the frame region (F). Also, the surfaces 211 and 212 of the light transmissive substrate 210 that may receive electrostatic crystal damage in the main pattern region M are also covered. On the other hand, the light blocking film patterns 230 and 230a of the remaining main pattern region M are exposed by the resist film pattern 242. In the development process for forming the resist film pattern 242, an area where electrostatic damage may occur, that is, a distance of several hundred μm or more and an interval between adjacent pattern structures 220/230 or a frame region F The resist film pattern 242 on the surfaces 211 and 212 of the light-transmitting substrate 210 exposed between the pattern structure 220 / 230a having a thickness of 1.5 μm or less and another pattern structure 220/230 or the frame region F. In this manner, electrons concentrated at the end of the light blocking film pattern 230a due to static electricity due to friction with the developer may be formed by using the resist film pattern 242 having conductivity as a movement path, or may be adjacent to another light blocking film pattern 230 or the adjacent light blocking film pattern 230. By easily moving to the light blocking layer pattern 230 of the frame region F, electrostatic damage of the light transmitting substrate 210 is prevented.

Next, as shown in FIG. 8, etching is performed to remove the light blocking film patterns 230 and 230a of FIG. 7 from which the resist film pattern 242 of FIG. 7 is exposed as an etching mask. This etching exposes the phase shift pattern 220 in the main pattern region M, while the phase shift pattern 220 in the frame region F is still covered by the light blocking pattern 230. do. After the etching is completed, a conventional strip process is performed to remove the resist film pattern 242 of FIG. 7.

9 is a plan view illustrating the principle of preventing electrostatic damage according to the present embodiment. Specifically, FIG. 9 is a view illustrating an example of the planar structure in the cross-sectional state illustrated in FIG. 7, and when associated with the cross-sectional structure of FIG. 7, the light blocking layer pattern 235 corresponds to the light blocking layer pattern 230a of FIG. 7. The other light blocking film patterns 236 adjacent to each other correspond to the other light blocking film patterns 230 of FIG. 7, and the regions indicated by "M" and the regions shown by "F" are the same as the main pattern area and the frame, respectively. Represents an area.

As shown in FIG. 9, in the main pattern region M, a light blocking film pattern 235 having a length of several hundred μm or more is disposed on the light-transmitting substrate 210, and the light blocking film pattern 235 is spaced within 1.5 μm. The light blocking layer pattern 236 is spaced apart from each other, and at the same time, spaced apart from the frame region F by 1.5 μm. In this case, the light-transmitting substrate 210 exposed between the light blocking layer pattern 235 and another light blocking layer pattern 236 adjacent to the light blocking layer pattern 235, and the light-transmitting substrate exposed between the light blocking layer pattern 235 and the frame region F adjacent to the light blocking layer pattern 235. The surface of the surface 210 is an area capable of receiving electrostatic damage, and thus, resist film patterns 243 and 244 remain in this area in addition to the frame area F. FIG. As described with reference to FIG. 7, in the developing process for forming the resist film patterns 242, 243, and 244, electrons concentrated at the end of the light blocking film pattern 235 due to static electricity due to friction with the developer have conductivity. The resist film pattern 243 can be easily moved to another adjacent light blocking film pattern 236 by using the movement path, thereby preventing the electrostatic damage of the translucent substrate 210 that occurs when the movement path of electrons is limited. Similarly, electrons concentrated at the end of the light blocking film pattern 235 can be easily moved to the light blocking film pattern in the adjacent frame region F by using the conductive resist film pattern 244 as a movement path. Electrostatic damage of the light transmitting substrate 210 that occurs when the movement path is limited is prevented.

1 and 2 are cross-sectional views illustrating an example of a method of manufacturing a phase inversion mask.

3 is a view showing for explaining the electrostatic damage phenomenon of the light-transmitting region in the method of manufacturing the phase inversion mask of FIGS.

4 to 8 are diagrams for explaining a method of manufacturing a phase inversion mask according to an embodiment of the present invention.

9 is a plan view showing a planar structure in the step shown in FIG.

Claims (4)

Forming pattern structures on the light transmissive substrate having a main pattern region and a frame region, in which phase reversal film patterns and light blocking film patterns are sequentially disposed; A photoresist film pattern is formed to cover the pattern structures of the main pattern area while covering the pattern structures of the frame area, but the photoresist film pattern remains on the surface of the light-transmitting substrate that may cause electrostatic damage in the main pattern area. To ensure; Removing the light blocking film pattern exposed in the main pattern area by the photoresist film pattern; And And removing the photoresist layer pattern. Claim 2 has been abandoned due to the setting registration fee. The method of claim 1, The light blocking layer pattern is a phase inversion mask manufacturing method formed using a chromium film. Claim 3 was abandoned when the setup registration fee was paid. The method of claim 1, The surface of the light transmissive substrate in which the electrostatic damage may occur in the main pattern region may include a light transmissive substrate exposed between a light shielding pattern having a length of several hundred μm or more and another adjacent light blocking pattern having a distance of 1.5 μm or less from the light blocking layer pattern. Method of manufacturing a phase inversion mask that is a surface. Claim 4 was abandoned when the registration fee was paid. The method of claim 1, The surface of the light transmissive substrate in which the electrostatic damage may occur in the main pattern region is a phase of the light transmissive substrate exposed between a light blocking pattern having a length of several hundred μm or more and a frame area having a distance of 1.5 μm or less from the light blocking film pattern. Inversion mask manufacturing method.

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