JP2000227651A - Phase shift mask and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase shift mask which enables an improvement in exposure dimensional accuracy without allowing illumination light to substantially receive the influence of shifter side walls and without depending on pattern shapes. SOLUTION: This process for production consists in forming differences in level on the surface of a transparent substrate 1 (c, forming a light shielding film 2 on the surface of the transparent substrate 1 (d), planarizing the light shielding film 2 by CMP(chemico-mechanical polishing) until the surfaces in the projecting parts of the differences in level of the transparent substrate 1 are exposed to form the light shielding film 2 as light shielding film patterns corresponding to the recessed parts of the differences in level of the transparent substrate 1 (e), then forming a phase shifter 4 so as to cover the entire part of the surfaces of the projecting parts at the differences in level of the substrate and the surface of the light shielding film patterns (f) and patterning the phase shifter 4 by wet etching to cover the surfaces of the desired projecting parts among the projecting parts at the differences in level of the substrate and the surfaces of the regions of the light shielding film patterns 2 adjacent thereto, thereby forming the phase shifter patterns 4 having edges on the light shielding film patterns 2 (h).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of photolithography technology used in the manufacture of semiconductor devices and the like, and more particularly to a phase shift mask used for projecting and exposing a fine pattern and a method of manufacturing the same. Things.

[0002]

2. Description of the Related Art
As an exposure photomask, a Levenson type phase shift mask in which a light shielding film and a phase shifter are periodically arranged on a transparent substrate is used. The Levenson-type phase shift mask will be described with reference to FIGS. 5 and 6 in comparison with a conventional transmission-type photomask that does not use a phase shifter. FIG.
FIG. 6 shows the configuration of a conventional photomask not using a phase shifter and the transmitted light intensity, and FIG. 6 shows the configuration of a Levenson-type phase shift mask and the transmitted light intensity.

In the photomask of FIG. 5, a light shielding film (pattern) 2 is formed on a lower surface of a transparent substrate 1 as shown in a sectional view of FIG. It is arranged in. Illumination light irradiated from above through the transparent substrate 1 and coming out of the opening between the adjacent light-shielding film patterns 2 forms an image on the surface of the semiconductor wafer via an optical system (not shown). When the distance between the openings becomes narrower, the diffracted light from the adjacent openings is superimposed on each other because the phases thereof are aligned with each other, and the image of the openings becomes difficult to separate. come. In FIG. 5, (b) shows the light amplitude distribution on the mask, (c) shows the light amplitude distribution on the wafer, and (d) shows the light intensity distribution on the wafer.

On the other hand, in the Levenson-type phase shift mask shown in FIG. 6, a light-shielding film pattern 2 is formed on a lower surface of a transparent substrate 1 as shown in FIG. The phase shifters (patterns) 4 are formed at every other opening in the openings formed between the adjacent light-shielding film patterns 2. The phase of light emitted from one of the adjacent openings is changed by 180 degrees with respect to the phase of light emitted from the other. Therefore, even if the interval between the openings becomes narrow, the light arriving from both of the adjacent openings in the region on the wafer corresponding to the boundary region of the adjacent openings cancels each other because the phases are inverted. Are separated. In FIG. 6, (b) shows the light amplitude distribution on the mask, (c) shows the light amplitude distribution on the wafer, and (d) shows the light intensity distribution on the wafer. As described above, in the mask using the phase shift method, when there is a repeated pattern,
By shifting the phase of the opening every other 180 degrees,
It is possible to dramatically improve the resolution.

Several types of mask structures of the Levenson type phase shift mask have already been proposed. When the Levenson-type phase shift mask was first proposed, a mask structure in which a transparent film called a phase shifter was formed on the mask as described above was used. However, a transparent film (sputter Si) serving as a phase shifter is formed on a mask substrate on which a light-shielding film (chromium film: film thickness: 100 nm) is formed by patterning.
When O ₂ , SOG, etc. are deposited, the thickness of the transparent film fluctuates near the edge of the step formed by the light-shielding film, and it has become clear that phase control is difficult. Therefore, recently, with the improvement of the dry etching technology in forming the phase shifter, the substrate dug-down type is becoming mainstream.

FIG. 7 shows three types of mask structures proposed for a substrate dug-down type. In FIG. 7, 1 is a transparent substrate, 2 is a light shielding film, and 4 is a dug-in phase shifter pattern. FIG. 7A shows a one-sided engraving method, and FIG.
FIG. 7B shows a double engraving method, and FIG. 7C shows a double trench method. All have been proposed in order to suppress the occurrence of a difference in exposure dimension due to the presence or absence of a phase shifter. 7A and 7B, the side wall of the shifter pattern 4 is recessed from the edge of the light-shielding film pattern, and the strength of the light-shielding film pattern 2 is difficult, and the amount of side wall recession is limited. Further, even in the case of FIGS. 7A to 7C, it is difficult to completely eliminate the dimensional difference in the exposure due to the presence or absence of the shifter in the hole type having the pattern for forming the contact hole. Particularly, in the Levenson-type phase shift mask, the difficulty of defect inspection and repair is the biggest factor that cannot be put into practical use.However, due to the decrease in exposure dimensional accuracy due to the phase difference error caused by the shifter film thickness and the existence of the shifter sidewall The reduction of the exposure dimensional difference generated based on the above is also an important issue.

[0007] Such problems of the conventional method will be further described. Here, the target pattern has a size of 0.2 μm.
The case of a line system and a hall system of m or less will be described. FIGS. 8 and 9 show the structure of a conventional Leverson type phase shift mask of a substrate dug-in type and the transmitted light intensity. Here, the reference numerals are the same as those in FIG. FIG. 8 is a plan view (a) of a mask and an AA ′ sectional view (b) thereof when applied to a line pattern, a light amplitude distribution on a mask (c), a light amplitude distribution on a wafer (d), and 6 shows the light intensity distribution (e) on the wafer. The feature of this mask structure is that the side wall (edge) of the phase shifter 4 is
Inward from one side by 150 nm. The reason is as follows. In other words, the illumination light that has passed through the shifter opening is diffracted by the shifter step side walls, and the light intensity on the wafer decreases.
For this reason, the shift of the shifter side wall is retracted to suppress the scattering of the diffracted light, thereby avoiding the occurrence of the difference in the exposure dimension due to the presence or absence of the phase shifter. FIG. 9 is a plan view (a) of a mask applied to a contact hole, and FIG.
An A ′ cross-sectional view (b), a light amplitude distribution on a mask (c), a light amplitude distribution on a wafer (d), and a light amplitude distribution on a wafer (e) are shown. In the case of a contact hole, since the four phase shifter edges are close to each other, the scattering of diffracted light appears more remarkably. Therefore, the light intensity at the shifter opening is lower than that of the line system. For this reason, it is difficult to completely eliminate the occurrence of the exposure dimensional difference due to the presence or absence of the shifter even in the case of the hole system, in which the amount of recess of the shifter side wall is set to 150 nm. In particular, the tendency is remarkably exhibited in a hole pattern of 0.2 μm or less. In this mask structure, since the eaves of the light-shielding pattern may be missing or peeled off, the limit of the retreat amount of the shifter side wall is 150 nm.

In order to solve the above problems, the present invention provides a phase shift mask capable of improving the exposure dimensional accuracy without substantially affecting the illumination light from the shifter side walls and irrespective of the pattern shape. To provide.

[0009]

According to the present invention, in order to achieve the above object, a step is formed on the surface of a transparent substrate, and a light shielding film is formed on the surface of the transparent substrate. The light-shielding film is flattened by CMP until the surface of the step of the substrate is exposed, whereby the light-shielding film is formed as a light-shielding film pattern corresponding to the recess of the step of the transparent substrate. Forming a phase shifter pattern having an edge on the light-shielding film pattern so as to cover the surface of the desired light-shielding film pattern and the surface of the region of the light-shielding film pattern adjacent thereto.
A method for manufacturing a phase shift mask is provided.

In one embodiment of the present invention, the step on the surface of the transparent substrate is formed by dry etching. In one embodiment of the present invention, the phase shifter pattern is formed by forming a phase shifter so as to cover the entire surface of the substrate step protrusion and the entire surface of the light shielding film pattern, and patterning the phase shifter. Made by In one embodiment of the present invention, the patterning of the phase shifter is performed by wet etching.

According to the present invention, in order to achieve the above object, a light-shielding film pattern is formed on a surface of a transparent substrate, a phase shifter is formed thereon, and the surface of the light-shielding film pattern is exposed. Until the phase shifter
A phase shift mask formed by flattening with P, thereby forming the phase shifter into a phase shifter pattern located between the light-shielding film patterns, and then removing an undesired one of the phase shifter patterns. And a method of manufacturing the same.

In one embodiment of the present invention, the formation of the light-shielding film pattern is performed by forming a light-shielding film so as to cover the entire surface of the transparent substrate and patterning the light-shielding film. In one embodiment of the present invention, the patterning of the light shielding film is performed by dry etching.
In one embodiment of the present invention, the removal of an undesired phase shifter pattern is performed by wet etching.

According to the present invention, in order to achieve the above object, a light-shielding film pattern is formed in a concave portion of a step formed on a surface of a transparent substrate. The surface of the step of the transparent substrate is flattened as a whole, and covers the surface of a desired one of the substrate step and the surface of the light-shielding film pattern region adjacent thereto. A phase shift mask, characterized in that a phase shifter pattern having an edge is formed on the light-shielding film pattern,
A light-shielding film pattern is formed on the surface of the transparent substrate, and a phase shifter pattern is disposed on a desired one of intermediate portions between adjacent ones of the light-shielding film patterns. A phase shift mask is provided, wherein the entire surface of the light-shielding film pattern is flattened.

In one embodiment of the present invention, the phase shifter pattern is made of SOG. In one embodiment of the present invention, the light-shielding film pattern comprises a chromium layer.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a Levenson-type phase shift mask of the present invention and a method of manufacturing the same will be described with reference to the drawings.

FIG. 1 shows a flow chart of a first embodiment of manufacturing a Levenson type phase shift mask according to the present invention.

First, as shown in FIG. 1A, a resist 3 is applied to a transparent substrate 1 made of synthetic quartz, and a first electron beam exposure is performed. Next, as shown in FIG. 1B, a resist (pattern) 3 is formed by developing the resist.
When electron beam exposure is performed on the transparent substrate 1, a conductive coating film (for example, Espacer: manufactured by Showa Denko KK) is formed on the resist 3 to prevent charge-up. This conductive film is removed by a water washing process before development. Although not shown, an alignment mark serving as a reference for positioning at the time of performing the second overlapping drawing described later is formed on the periphery of the mask substrate by exposure.

Next, as shown in FIG. 1C, the resist 3 is removed after the transparent substrate 1 is dug into a pattern by 100 nm by dry etching with a fluorine-based gas (CHF ₃ + O ₂ ). . Next, as shown in FIG. 1D, a chrome light shielding film 2 is formed on the transparent substrate 1 by sputtering. This light shielding film 2 is a chromium layer having a thickness of 150 to 200 nm. The light shielding film 2 is formed so as to completely cover the step of the transparent substrate 1.

Next, as shown in FIG.
Of a substrate 1 having a chemical mechanical polishing (CMP)
transparent substrate 1 polished by ishing (chemical mechanical polishing)
The light shielding film 2 is selectively and partially removed until the upper surface of the step is exposed. Thereby, the light-shielding film pattern 2 corresponding to the concave portion of the step of the transparent substrate 1 is formed. CMP is used as a flattening technique when forming a multilayer wiring of a semiconductor device, and a slurry (polishing solvent) is dropped on a rotating pad (urethane polishing cloth), and the substrate 1 The polishing surface is contacted to selectively polish only the light shielding film 2. In addition, CMP can polish an oxide film type and a metal type, and can selectively polish a desired material by selecting a slurry according to the purpose. As a result, the light-shielding film 2 is formed only in the concave portion of the step portion of the transparent substrate 1, and a light-shielding film pattern is obtained. Flattened. Here, since the light-shielding film is also formed on the alignment mark around the mask substrate, the light-shielding film in this portion is removed by immersion in a ceric ammonium nitrate aqueous solution to form a mask substrate step required for overwriting. I do.

Next, as shown in FIG. 1F, a SOG (Spin On Glass: Tokyo Ohka Co., Ltd.) film 4 serving as a phase shifter is formed on the mask substrate on which the light shielding film pattern is formed. Assuming that the refractive index of the SOG film is n and the wavelength of the exposure light source is λ, d = λ / 2 (n−
Given in 1). Here, assuming that KrF excimer laser (wavelength: 248 nm) exposure is used, heat treatment at 200 degrees is performed after SOG coating, and the phase shifter layer 4 is formed to a thickness of 248 nm according to the above equation. This S
The thickness of the OG shifter 4 can be measured by spectroscopic ellipsometry. If the film thickness does not reach the desired value, the film is peeled off by using an SOG etching solution to be described later and the film is formed again to have a predetermined film thickness (matching the phase). Next, the phase shifter 4
A resist 3 'is applied thereon, and the shifter pattern is overwritten using the alignment marks formed by the previous drawing. Next, as shown in FIG. 1G, a pattern of the resist 3 ′ is formed by developing the resist. Where S
Since the OG film 4 is heat-treated, it does not mix with the resist 3 '.

Next, as shown in FIG. 1H, a wet etching solution (BHF: buffered hydrofluoric acid / water = 1: 1)
30), the SOG film 4 in the resist opening is etched to remove the resist. This etchant is S
Since the OG film: transparent substrate = 1: 50 or more has an etching selectivity, the transparent substrate 1 is not etched. Further, the phase difference of the actual pattern portion can be measured by a phase difference measuring device (MPM-248: manufactured by Lasertec).

Through the above steps, a Levenson-type phase shift mask is manufactured.

In the present embodiment, a step for forming a light-shielding pattern is formed on the transparent substrate 1, and the light-shielding film formed on this step is selectively selectively removed by a surface flattening process by CMP polishing. Then, a light-shielding pattern is formed in the concave portion of the substrate step, and the SOG phase shifter is formed on the flattened mask substrate with the light-shielding pattern, so that the in-plane uniformity of the film thickness of the phase shifter is improved. Thus, highly accurate phase difference control becomes possible. The SOG phase shifter can be easily formed by wet etching without using dry etching. In this process, the shifter has a forward tapered shape due to wet etching, but the shifter edge is located in the light-shielding pattern area and is hidden by the light-shielding pattern at the time of exposure, so there is a problem during exposure using this mask There is no.

In the present embodiment, there is no need to retreat the side wall of the phase shifter pattern by wet etching as in the conventional method. Therefore, problems such as peeling of the light-shielding film pattern and missing of the eaves portion due to penetration of the etching solution between the light-shielding film pattern and the phase shifter pattern do not occur.

Further, in this embodiment, since the phase shifter pattern is formed on the chromium light-shielding film pattern, the SOG shifter film thickness can be measured on an actual substrate by spectral ellipsometry. When the adjustment of the shifter film thickness is insufficient, it is possible to easily peel off the shifter and perform film formation again. In the Levenson-type phase shift mask, in order to make the exposure dimension difference due to the presence or absence of the shifter 10 nm or less, the shifter film thickness must be 180 ± 3 in terms of phase.
Although it is necessary to control within a degree, according to this embodiment,
This is quite possible.

FIG. 2 shows the configuration of the Levenson-type phase shift mask of this embodiment and the transmitted light intensity. 2, (a) shows a cross-sectional view of the mask, (b) shows the light amplitude distribution on the mask, (c) shows the light amplitude distribution on the wafer, and (d) shows the light intensity on the wafer. Shows the distribution.

Light emitted from the light-shielding pattern opening forms an image on a wafer through a lens optical system (not shown). The light that passes through the phase shifter pattern 4 is 180 degrees out of phase with respect to the light that does not pass, that is, the phase of light exiting from one of the adjacent openings is reversed with respect to the phase of light exiting the other. . For this reason, even if the space between the mask openings becomes narrower and light comes from both of the adjacent openings to a region on the wafer corresponding to the boundary region of the adjacent openings on the wafer, these lights have opposite phases. Therefore, the light intensity indicating the opening boundary region is sufficiently smaller than the light intensity indicating the opening, so that the image of the opening is well separated and the resolution is good.

Further, since the edge of the SOG shifter pattern is formed inside the light-shielding pattern area, the illumination light passing through the shifter-equipped opening is not scattered by the diffracted light by the shifter side wall (that is, the shifter opening). Irradiation uniformly on the wafer (without the problem of scattering of diffracted light). For this reason. Even in the case of forming a contact hole, a high-precision pattern can be formed without a dimensional difference due to the presence or absence of a shifter.

Further, in the phase shift mask of the present embodiment, the light-shielding film pattern 2 is formed in the stepped concave portion of the transparent substrate 1, and the shifter pattern is formed so as to extend over the adjacent light-shielding pattern. For this reason, the film thickness of the shifter pattern is highly uniform, and the film thickness of the shifter portion corresponding to the edge portion of the light-shielding pattern is substantially the same as the film thickness of the other portions. The problem of poor control does not occur.

FIG. 3 shows a flow chart of a second embodiment of manufacturing a Levenson-type phase shift mask according to the present invention.

First, as shown in FIG. 3A, a 248 nm-thick chrome light-shielding film 2 is formed on a transparent substrate 1. The thickness of the chrome light-shielding film is set to be the same as the desired thickness of the phase shifter. Next, a resist 3 is applied and electron beam exposure is performed.
Next, as shown in FIG. 3B, the resist is developed,
A resist pattern 3 is formed.

Next, as shown in FIG. 3C, the light-shielding film 2 is processed into a pattern by dry etching using a chlorine-based gas (Cl ₂ + CHCl ₃ ).
Is peeled off. Next, as shown in FIG. 3D, the SOG shifter 4 is formed by spin coating. This SOG shifter has a thickness of 400 nm to completely cover the light shielding pattern 2.
A film is formed to a thickness of 500 nm, and a heat treatment at 200 ° C. is performed.
The mask substrate is selectively polished only by SOG by CMP polishing and partially removed, and as shown in FIG. 3E, SOG is removed until the upper surface of the light shielding film pattern 2 is exposed. Thereby, the phase shifter is formed into a pattern.

Again, as shown in FIG. 3 (f), a resist 3 'is applied, and overlay drawing and development of the shifter opening pattern are performed by electron beam exposure. Next, as shown in FIG. 3 (g), the SOG of the resist opening is formed using a wet etching solution (BHF: buffered hydrofluoric acid / water = 1: 30).
Is removed. Next, as shown in FIG. 3H, the resist is removed. This etching solution is SOG: transparent substrate =
Since it has an etching selectivity of 1:50 or more, the transparent substrate is not etched.

Through the above steps, a Levenson-type phase shift mask is manufactured.

In the present embodiment, a light-shielding film pattern having a predetermined thickness is formed on the transparent substrate 1, and the SOG film formed on the step formed by the light-shielding film pattern is subjected to a surface flattening process by CMP polishing. Since the phase shifter pattern is formed by selectively removing the phase shifter pattern, the in-plane uniformity of the film thickness of the phase shifter pattern is improved, and highly accurate phase difference control becomes possible.

In this embodiment, there is no need to retreat the side wall of the phase shifter pattern by wet etching unlike the conventional method. Therefore, problems such as peeling of the light-shielding film pattern and missing of the eaves portion due to penetration of the etching solution between the light-shielding film and the phase shifter pattern do not occur.

FIG. 4 shows the configuration of the Levenson-type phase shift mask of this embodiment and the transmitted light intensity. 4A shows a cross-sectional view of the mask, FIG. 4B shows the light amplitude distribution on the mask, FIG. 4C shows the light amplitude distribution on the wafer, and FIG. 4D shows the light intensity on the wafer. Shows the distribution.

The light emitted from the light-shielding pattern opening forms an image on the wafer through the lens optical system. The light passing through the phase shifter pattern 4 has a phase of 18 with respect to the light not passing.
The phase of light that is shifted by 0 degrees, that is, the light that exits from one of the adjacent openings is opposite to the phase of the light that exits the other. For this reason, even if the interval between the mask openings is reduced, and light comes from both the adjacent openings to the region on the wafer corresponding to the boundary region between the adjacent openings on the wafer,
Since these lights have opposite phases, they cancel each other out,
The light intensity indicating the opening boundary region is sufficiently smaller than the light intensity indicating the opening, so that the image of the opening is well separated and the resolution is good.

Further, in the phase shift mask of the present embodiment, the light-shielding film pattern 2 and the shifter pattern 4 have the same film thickness, and the film thickness of the shifter pattern is high.
In this embodiment, although the light intensity on the wafer is slightly lower than that in the first embodiment, the diffraction of light by the edge of the light-shielding film pattern is the same regardless of whether or not it comes into contact with the phase shifter pattern. Therefore, the problem of poor phase control near the edge of the light-shielding film pattern does not substantially occur.

[0040]

As described above, according to the present invention,
There is provided a Levenson-type phase shift mask having good dimensional accuracy of a periodic exposure pattern irrespective of the pattern shape, without being affected by the light intensity decrease due to the step side wall of the phase shifter.

[Brief description of the drawings]

FIG. 1 is a flowchart of a first embodiment of manufacturing a Levenson-type phase shift mask according to the present invention.

FIG. 2 is a diagram showing a configuration of a first embodiment of manufacturing a Levenson-type phase shift mask of the present invention and a transmitted light intensity.

FIG. 3 is a flowchart of a second embodiment of manufacturing a Levenson-type phase shift mask according to the present invention.

FIG. 4 is a diagram showing a configuration and a transmitted light intensity of a second embodiment for manufacturing a Levenson-type phase shift mask of the present invention.

FIG. 5 is a diagram showing a configuration of a conventional photomask not using a phase shifter and transmitted light intensity.

FIG. 6 is a diagram showing a configuration of a Levenson-type phase shift mask and transmitted light intensity.

FIG. 7 is a diagram showing three types of mask structures of a substrate dug-down type.

FIG. 8 is a diagram illustrating the configuration of a substrate dug-down type Levenson-type phase shift mask and transmitted light intensity.

FIG. 9 is a diagram illustrating a configuration of a substrate dug-down type Levenson-type phase shift mask and transmitted light intensity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Shielding film (pattern) 3, 3 'resist 4 Phase shifter (pattern)

Claims (12)

[Claims] 1. A step is formed on a surface of a transparent substrate, a light-shielding film is formed on the surface of the transparent substrate, and the light-shielding film is planarized by CMP until a surface of a convex portion of the step on the transparent substrate is exposed. Thus, the light-shielding film is formed as a light-shielding film pattern corresponding to the concave portion of the step of the transparent substrate, and then the surface of the desired one of the substrate step-shaped convex portions and the surface of the region of the light-shielding film pattern adjacent thereto are formed. A method for manufacturing a phase shift mask, comprising forming a phase shifter pattern having an edge on the light shielding film pattern so as to cover the same. 2. The method according to claim 1, wherein the step on the surface of the transparent substrate is formed by dry etching. 3. The phase shifter pattern is formed by forming a phase shifter so as to cover the entire surface of the stepped portion of the substrate and the entire surface of the light-shielding film pattern, and patterning the phase shifter. The method for manufacturing a phase shift mask according to claim 1, wherein: 4. The method according to claim 3, wherein the patterning of the phase shifter is performed by wet etching. 5. A light-shielding film pattern is formed on a surface of a transparent substrate, a phase shifter is formed thereon, and the phase shifter is flattened by CMP until a surface of the light-shielding film pattern is exposed. A phase shifter pattern located between the light-shielding film patterns, and thereafter, removing a desired one of the phase shifter patterns. 6. The light shielding film pattern is formed by forming a light shielding film so as to cover the entire surface of the transparent substrate and patterning the light shielding film. 3. The method for manufacturing a phase shift mask according to item 1. 7. The method according to claim 6, wherein the patterning of the light shielding film is performed by dry etching. 8. The method for manufacturing a phase shift mask according to claim 5, wherein removal of an undesired phase shifter pattern is performed by wet etching. 9. A light-shielding film pattern is formed in a concave portion of a step formed on a surface of a transparent substrate, and the surface of the light-shielding film pattern and the surface of a convex portion of the step of the transparent substrate are entirely flattened. A phase shifter pattern having an edge on the light shielding film pattern is formed so as to cover the surface of a desired one of the substrate step protrusions and the surface of the light shielding film pattern region adjacent thereto. A phase shift mask, characterized in that: 10. A light-shielding film pattern is formed on a surface of a transparent substrate, and a phase shifter pattern is disposed at a desired one of intermediate portions between adjacent light-shielding film patterns. A phase shift mask, wherein the surface of the shifter pattern and the surface of the light-shielding film pattern are entirely flattened. 11. The phase shift mask according to claim 9, wherein the phase shifter pattern is made of SOG. 12. The phase shift mask according to claim 9, wherein said light-shielding film pattern comprises a chromium layer.