WO2013058385A1

WO2013058385A1 - Large-sized phase-shift mask, and method for producing large-sized phase-shift mask

Info

Publication number: WO2013058385A1
Application number: PCT/JP2012/077157
Authority: WO
Inventors: 一樹木下; 敦飛田; 悟二嶋
Original assignee: 大日本印刷株式会社
Priority date: 2011-10-21
Filing date: 2012-10-19
Publication date: 2013-04-25
Also published as: JPWO2013058385A1; TWI584058B; CN103890657A; KR20140093215A; TW201329614A; JP6127977B2; CN110083008A

Abstract

Provided are: a phase-shift mask which is a large-sized photomask that enables the exposure of a large-sized area to light and has a constitution suitable for the formation of a fine pattern; and a method for producing the phase-shift mask. A large-sized phase-shift mask is produced, which can be produced easily and enables the transfer of a fine pattern. The large-sized phase-shift mask has such a constitution that a light-shielding film contains chromium or a chromium compound as the main component, a phase-shift film contains chromium oxide or oxidized chromium nitride as the main component, and the phase-shift film is laminated on the light-shielding film in the light-shielding area. The reflectance of the light-shielding area can be reduced by employing such a constitution that an anti-reflective film comprising a chromium compound is additionally provided between the light-shielding film and the phase-shift film.

Description

Large phase shift mask and manufacturing method of large phase shift mask

The present invention relates to a photomask, and more particularly to a large photomask used for manufacturing an active matrix display device such as a liquid crystal display device or an EL display device, and a method for manufacturing the large photomask.

Changes in the specifications of photomasks used in the manufacture of flat panel displays (abbreviated as FPD) are typified by the large screen and high definition found in thin televisions using liquid crystal display devices (abbreviated as LCD). Regarding the increase in screen size, the size of the glass substrate called the first generation used for manufacturing in the beginning of 1990 when liquid crystal flat-screen televisions were mass-produced was 300 mm x 400 mm, but began to be used for manufacturing around 2002. The size of the 5th generation glass substrate is 1100 mm × 1300 mm, and the size of the 8th generation glass substrate, which has been used for manufacturing around 2006, has reached 2140 mm × 2460 mm.

The high-definition of liquid crystal display devices initially advanced with higher pixels in personal computer displays. The VGA display was 640 × 480 pixels, but the XGA display was 1024 × 768 pixels, the SXGA display was 1280 × 1024 pixels, and the UXGA display was 1600 × 1200 pixels. Along with the increase in the number of pixels, the pixel pitch has been reduced from 0.33 mm to 0.24 mm and 0.20 mm. Furthermore, in a smart phone or the like, it is 4.5 type and has 1280 × 720 pixels, and the pixel pitch reaches 0.077 mm (329 ppi). In addition, high-definition (HDTV) has 1920 × 1080 pixels, but there is also a display in which pixels are further interpolated to 3840 × 2160 pixels (referred to as a 4K liquid crystal panel), which is four times the number of pixels.

An exposure apparatus for manufacturing the liquid crystal display device as described above and a photomask used for the exposure apparatus will be described below. A cell of a color TFT (Thin Film Transistor) liquid crystal display device, which is a typical liquid crystal display device, is assembled by sealing liquid crystal between a separately manufactured color filter and a TFT array substrate. Furthermore, a liquid crystal display module is completed by incorporating a peripheral drive circuit and a backlight into the liquid crystal display cell, which converts the video signal into a TFT drive signal and supplies it.

The TFT array substrate is a substrate in which a large number of TFTs are arranged in a matrix, and is a substrate that controls display (ON) and non-display (OFF) of each pixel of the liquid crystal. As an example, it is manufactured by the following process. 1) a gate wiring process for patterning a gate electrode material such as MoW on a glass substrate; 2) a semiconductor part forming process for patterning an A-Si film in an island shape after forming a gate insulating film; ) Transparent display electrode formation step for patterning ITO film (tin-doped indium oxide film), 4) Step for forming contact hole in gate insulating film, 5) Pattern formation of conductor layer such as Al, source / drain of TFT and The TFT array substrate is manufactured through a manufacturing process including a process of forming a signal line and a process of 6) forming an insulating protective film on the surface.

Formation of the pattern used in each step of the above TFT array substrate manufacturing process is performed with a projection exposure apparatus (also referred to as a projection exposure apparatus) with an equal magnification using a large-sized mask with an equal magnification of 1: 1. . At present, the same size projection exposure method using a large mask has become a standard manufacturing method for patterning a TFT array substrate with high productivity and high accuracy. Note that a cost effective proximity exposure method is a standard manufacturing method for forming a color filter pattern. Proximity exposure is an exposure method in which a mask and an object to be exposed are arranged close to each other with a gap of about several tens of μm to 100 μm, and parallel light is irradiated from behind the mask.

The large mask for the TFT array substrate originally started with a size of 350 mm × 350 mm, but has increased in size with the increase in the size of the projection type exposure apparatus used for manufacturing the TFT array substrate. There are two types of projection-type exposure apparatuses used in the manufacture of TFT array substrates: a mirror projection exposure system that uses a mirror system to project and expose a mask pattern onto a workpiece, and a lens projection exposure system that uses a lens system. is there. The size of the large mask to be used differs depending on the specifications of each exposure apparatus. For the fifth generation glass substrate, a large mask having a size of 520 mm × 610 mm is used for the mirror projection exposure method, and 800 mm × 920 mm is used for the lens projection exposure method. A large size mask is used. Further, for the eighth generation glass substrate, a large mask having a size of 850 mm × 1400 mm is used in the mirror projection exposure method, and a large mask having a size of 1220 mm × 1400 mm is used in the lens projection exposure method.

The diagonal length of the normal mask (6-inch reticle) for a normal semiconductor is about 154 mm, whereas the diagonal length of the large mask is 495 mm for the original mask, and the fifth generation mirror projection exposure system. Is about 801 mm, and the large mask for the eighth generation lens projection exposure system has been increased to 1856 mm.

As described above, the large mask used for pattern formation of the TFT array substrate is 3.2 to 12 times the diagonal length ratio of the mask for the semiconductor wafer. Furthermore, the area ratio directly related to the manufacturing cost (film formation time, inspection time, etc.) is 10 to 144 times. Due to the cost requirements due to such a large size, the layer structure of the large mask is composed of a light shielding film mainly composed of chromium laminated on quartz glass, and chromium oxide or oxynitride laminated on the light shielding film. It is composed of two layers of an antireflection film mainly composed of chromium. The light-shielding film preferably has a transmittance of 0.1% or less at the exposure wavelength used, and the antireflection film preferably has a reflectance of 30% or less at the exposure wavelength used.

As described above, while the TFT array substrate has been increased in size, in recent years, pattern miniaturization has been required. That is, it is required to uniformly image a fine pattern close to the resolution limit of the exposure apparatus or a fine pattern close to the resolution limit of the exposure apparatus over the entire exposure region.

When a resist is exposed using a binary photomask on which a fine line-and-space (L / S) pattern below the resolution limit of the exposure apparatus is formed, the line (light-shielding) of the line on the photomask is blocked on the imaging plane. The amplitude of the exposure intensity corresponding to the part and the space (transmission) part becomes small, the exposure amount of the part corresponding to the space (transmission) part does not reach the threshold value of the resist sensitivity, and as a result the pattern is developed even if the resist is developed Is not formed.

As a conventional solution to such a problem, Patent Document 1 (Japanese Patent Laid-Open No. 2009-4242753) proposes a method using a gray tone mask. A description will be given with reference to FIG. 4 cited from FIG. 1 described in Patent Document 1 and FIG. 5 added to explain FIG.

As illustrated in FIG. 4A, a photomask 50 exemplified in the prior art includes a light-shielding portion 54 formed by a light-shielding film 52 that does not have a fine pattern on a transparent substrate 51, and a semi-transparent film that does not have a fine pattern. 53, a semi-transparent part 55, a fine pattern part 56 (comprising a translucent part and a semi-transparent part of the semi-transparent film 53), and a translucent part 57 (the transparent substrate 51 is exposed). ) And 4 regions are formed.

When the above-described photomask 50 exemplified in the prior art is exposed using the exposure light 40 and the pattern is transferred to the photoresist film (positive resist) 63 on the transfer target 60, as shown in FIG. In addition, a thick film remaining film region 63a after development, a thin film remaining film region 63b, a fine pattern region 63c corresponding to the fine pattern portion 56 on the photomask 50, and a substantially remaining film are formed on the transfer target 60. A transfer pattern (resist pattern) composed of a region 63d without a film is formed. Note that reference numerals 62 a and 62 b in FIG. 4 indicate films stacked on the substrate 61 in the transfer target 60.

FIG. 5 illustrates and explains the effect of the fine pattern 56 of the semipermeable membrane. That is, when a fine pattern is formed with a light-shielding film as in a general binary mask (FIG. 5B), the exposure light amount distribution shape 74c is such that the positive resist is formed even at the peak portion of the exposure amount corresponding to the translucent portion. The exposure dose 75 that passes through is not reached, and no pattern is formed. On the other hand, when the fine pattern 56 of the semi-transmissive film is exposed and transferred using the photomask 50 (FIG. 5A), the amount of exposure light transmitted is the fine pattern of the light shielding film of a general binary mask. It becomes larger than the transmission amount of the exposure light quantity of the part. When the fine pattern is formed with the semi-transmissive film, the distribution pattern 73c of the exposure light amount reaches the exposure amount 75 at which the positive resist comes off at the peak portion of the exposure amount corresponding to the translucent portion. Thus, the pattern 63c can be formed on the resist.

On the other hand, when the fine pattern 56 of the semi-transmissive film 53 is transferred by exposure using such a conventional photomask 50, the amount of exposure light transmitted is the exposure of the light shielding pattern portion by the light shielding film of a general binary mask. It becomes larger than the amount of transmitted light, and the contrast of the exposure light amount distribution decreases. For this reason, when the resist residual film value of the fine pattern region 63c on the transfer target when the fine pattern portion 56 of the semi-transparent film is transferred, the normal light shielding film pattern is transferred (for example, the thick film residual film region 63a). ) Smaller than the resist remaining film value. (Although a positive type photoresist is described as an example, the same applies to a negative type photoresist.) In this case, the exposure amount is adjusted in order to appropriately perform the subsequent etching process of the transferred object. In the development process of the photoresist after exposure, it is necessary to appropriately adjust the conditions to suitably adjust the resist residual film value.

JP 2009-42753 A

As described above, a photomask used for manufacturing a flat display typified by a liquid crystal display device has been increased in size, but on the other hand, the display pixel pitch of the flat display has been miniaturized and the photomask has been developed. There is also an increasing demand for finer transfer patterns.

Therefore, as a photomask that replaces the conventional binary mask, it has a transparent substrate and a phase shift film formed in a pattern on the transparent substrate, and a region where the transparent substrate is exposed is formed as a transmission region and a phase shift film. It has been studied to use a phase shift mask having a configuration in which a region to be used is a phase shift region. The above-described phase shift mask suppresses the spread of light intensity by arranging the phase shift region at a position that cancels out the light amplitude of the spread portion of the light amplitude distribution of the transmission region caused by the resolution limit, thereby reducing the finer pattern. Can be exposed.
However, since the phase shift film generally has a light shielding ability lower than that of the light shielding film of the binary mask and becomes a translucent film, when the exposure is performed using the phase shift mask described above, the transmission region and In the portion corresponding to the boundary of the phase shift region, the resist pattern has little spread, and the side surface can be formed in a sharp shape. However, in the portion corresponding to the central portion of the phase shift region, the phase shift film There is a problem that the resist has a dent due to its own transmittance. In addition, although the resist having the dent can exhibit the function of protecting the lower layer, the resist having the dent may be detected as a defect in the inspection performed after the resist development process. Therefore, a resist that originally has a protective function cannot be used because it is determined to be a defective product by inspection, and there is a problem that productivity of a TFT array substrate or the like is lowered.

The present invention is a phase shift mask for transferring a pattern by increasing the contrast of the exposure light quantity distribution of a fine pattern on the imaging surface when transferring a pattern to a transfer medium by exposure, and having a phase suitable for a large photomask. A shift mask and a manufacturing method thereof are provided. In the present application, a mask having a side length of 350 mm or more is used as a large photomask.

(First means)
The first means of the present invention includes a transparent substrate, a light shielding film formed on the transparent substrate, and a translucent phase shift film formed on the transparent substrate,
A transmission region where the transparent substrate is exposed; a light shielding region where the light shielding film is provided on the transparent substrate; and a phase shift region where only the phase shift film is provided on the transparent substrate, And the phase shift region has an adjacent pattern, the phase shift region is adjacently disposed between the transmission region and the light shielding region, and the exposure light transmitted through the phase shift region is the transmission region. In the phase shift mask whose phase is reversed with respect to the exposure light transmitted through
The light shielding film includes chromium or a chromium compound as a main component, the phase shift film includes chromium oxide or chromium oxynitride as a main component, and a phase shift film is stacked on the light shielding film in the light shielding region. A large phase shift mask.

By using the large phase shift mask of the first means, the contrast of the exposure pattern can be increased with respect to the fine pattern in a large area, and the existing large hard mask blanks can be used as a starting material for production. The manufacturing cost of a large phase shift mask can be reduced.

(Second means)
The second means of the present invention is the large phase shift mask according to the first means, further comprising an antireflection film between the light shielding film and the phase shift film in the light shielding region. is there.

According to the second means, it is possible to prevent the reflection of the surface of the light shielding region of the large phase shift mask and to prevent the transfer accuracy from being lowered due to stray light during exposure.

(Third means)
According to a third means of the present invention, any one of the first means and the second means is characterized in that the width of the phase shift region is in the range of 0.25 μm or more and 3.5 μm or less. 2. A large phase shift mask according to item 1.

According to the third means, the effect of the phase shift that increases the contrast of the exposure pattern can be obtained satisfactorily.

(Fourth means)
According to a fourth means of the present invention, in any one of the first means to the third means, the width of the narrowest part of the transmission region is a width in the range of 1 μm or more and 6 μm or less. The large phase shift mask described in 1.

According to the fourth means, the effect of the phase shift that increases the contrast of the exposure pattern can be obtained satisfactorily.

(Fifth means)
According to a fifth means of the present invention, in any one of the first to fourth means, the light transmittance of the phase shift film with exposure light is 4% or more and 15% or less. The large phase shift mask described in 1.

According to the fifth means, the effect of the phase shift that increases the contrast of the exposure pattern can be obtained satisfactorily.

(Sixth means)
The sixth means of the present invention comprises a transparent substrate, a light shielding film formed on the transparent substrate, and a translucent phase shift film formed on the transparent substrate, wherein the transparent substrate is exposed. An area, a light-shielding area in which the light-shielding film is provided on the transparent substrate, and a phase shift area in which only the phase-shift film is provided on the transparent substrate, and the transmission area and the phase shift area are adjacent to each other. A phase shift area is disposed adjacent to the light-transmitting area and the light-shielding area, and the exposure light transmitted through the phase shift area corresponds to the exposure light transmitted through the transmission area. A method of manufacturing a phase shift mask for manufacturing a phase shift mask having an inverted phase,
A step of preparing a blank with a photosensitive resist, which is obtained by applying a photosensitive resist to a blank in which a light-shielding film made of chromium or a chromium compound is laminated on one surface of the transparent substrate;
A process of exposing a desired pattern to a blank with a photosensitive resist with a drawing apparatus, developing it, performing wet etching, removing the photosensitive resist, and patterning a light-shielding film;
Forming a phase shift film made of a chromium compound on the transparent substrate and the patterned light-shielding film;
From the step of applying a photosensitive resist to the formed phase shift film, exposing and developing a desired pattern with a drawing apparatus, performing wet etching, removing the photosensitive resist, and patterning the phase shift film This is a manufacturing method of a large phase shift mask.

According to the sixth means of the present invention, a large chrome hard mask blank can be used as a starting material for manufacturing, and furthermore, the pattern formation of the phase shift film can be performed by wet etching, so that the manufacturing cost of the large phase shift mask can be reduced. The effect of suppressing is great.

(Seventh means)
The seventh means of the present invention comprises a transparent substrate, a light shielding film formed on the transparent substrate, and a translucent phase shift film formed on the transparent substrate, wherein the transparent substrate is exposed. An area, a light-shielding area in which the light-shielding film is provided on the transparent substrate, and a phase shift area in which only the phase-shift film is provided on the transparent substrate, and the transmission area and the phase shift area are adjacent to each other. A phase shift area is disposed adjacent to the light-transmitting area and the light-shielding area, and the exposure light transmitted through the phase shift area corresponds to the exposure light transmitted through the transmission area. A phase shift mask in which the phase is reversed, the phase shift film is laminated on the light shielding film in the light shielding region, and an antireflection film is further provided between the light shielding film and the phase shift film in the light shielding region Manufacture A method of manufacturing a phase shift mask,
On one surface of the transparent substrate, a photosensitive resist was applied to a blank laminated in the order of a light shielding film mainly composed of chromium and an antireflection film mainly composed of chromium oxide or chromium oxynitride. A step of preparing blanks with a photosensitive resist;
Exposing a desired pattern to a blank with a photosensitive resist with a drawing apparatus, developing, wet etching, removing the photosensitive resist, and patterning the light-shielding film and the antireflection film; and
Forming a phase shift film made of a chromium compound on the transparent substrate and the patterned light shielding film and the antireflection film;
From the step of applying a photosensitive resist to the formed phase shift film, exposing and developing a desired pattern with a drawing apparatus, performing wet etching, removing the photosensitive resist, and patterning the phase shift film This is a manufacturing method of a large phase shift mask.

According to the seventh means of the present invention, it is possible to use a two-layer large chromium hard mask blank having an antireflection film as a starting material for manufacturing, and furthermore, pattern formation of the phase shift film can be performed by wet etching. The effect of suppressing the manufacturing cost of a large phase shift mask having a prevention film is great.

By using the large phase shift mask of the present invention, the contrast of the exposure pattern can be increased with respect to a fine pattern in a large area. Furthermore, as a starting material for manufacturing, an existing large-sized hard mask blank whose light-shielding film is a film containing chromium as a main component can be used, and a large-sized phase shift mask can be manufactured at low cost.

FIG. 1 is a sectional view for explaining the structure and operation of a large phase shift mask according to the present invention. FIG. 2 is a sectional view showing a manufacturing process of a large phase shift mask according to the present invention. FIG. 3 is an explanatory diagram comparing the effect of improving the contrast of the exposure intensity distribution of the large phase shift mask according to the present invention with a conventional binary mask. FIG. 4 is a cross-sectional view schematically showing transfer of a fine pattern with a halftone mask which is a conventional technique. FIG. 5A is a diagram for schematically explaining the exposure intensity distribution when exposed with the halftone mask of FIG. 4, and FIG. 5B is the exposure intensity distribution when a fine pattern is exposed with a binary mask for comparison. FIG. FIG. 6 is a schematic plan view showing an example of a large phase shift mask in the embodiment of the present invention. FIG. 7 is a view for explaining the exposure intensity distribution of the large phase shift mask in the embodiment of the present invention. FIG. 8 is an enlarged view of a portion C in FIG. FIG. 9 is an enlarged view of a portion D in FIG.

Hereinafter, with reference to the drawings, a configuration of a large phase shift mask of the present invention and an embodiment of a manufacturing method thereof will be described.

FIG. 1A is a cross-sectional view schematically showing the structure of an embodiment of a large phase shift mask of the present invention. FIGS. 1B and 1C are diagrams showing the amplitude and intensity of the exposure light transmitted through the large phase shift mask on the imaging plane. 2 (a) to 2 (f) are diagrams for explaining the manufacturing process of the large phase shift mask of the present invention.

(Configuration of large phase shift mask)
As shown in FIG. 1A, the configuration of the large phase shift mask 1 of the present invention is formed on a transparent substrate 2, a light shielding film 3 formed on the transparent substrate 2, and the transparent substrate 2. A translucent region 6 having a translucent phase shift film 5, the transparent substrate 2 being exposed, a light shielding region 7 in which the light shielding film 3 is provided on the transparent substrate 2, and the phase on the transparent substrate 2. A phase shift region 8 provided with only the shift film 5; the transmission region 6 and the phase shift region 8 have adjacent patterns; and the phase shift region between the transmission region 6 and the light shielding region 7 8 is a phase shift mask in which the exposure light transmitted through the phase shift region 8 is inverted in phase with respect to the exposure light transmitted through the transmission region 6.

The light shielding film 3 has chromium as a main component, the phase shift film 5 has chromium oxynitride or chromium oxide as a main component, and the phase shift film 5 is laminated on the light shielding film 3 in the light shielding region 7. Here, the large phase shift mask is a mask having a length of at least one side of 350 mm or more.

The effect of the edge-enhanced phase shift mask on the image plane will be briefly described. FIG. 1B shows the amplitude distribution of light on the imaging plane (specifically, the photosensitive resist surface) of the large phase shift mask, and FIG. 1C shows the imaging plane of the large phase shift mask. The light intensity distribution is shown. The light intensity is obtained by squaring the light amplitude, and the light amplitude takes a positive or negative value along with its phase, whereas the light intensity (same as energy) shows only a positive value. Moreover, the exposure light 40 is irradiated in the direction of the light shielding film 3 from the transparent substrate 2 side, as shown to Fig.1 (a). The exposure light 40 is selected from g-line (wavelength 436 nm), h-line (wavelength 405 nm), i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), KrF excimer laser (193 nm). Can do. Practically, since the pattern formation of the TFT array substrate is a large area and a large amount of light is required for exposure, two wavelengths of i-line alone, h-line, i-line, or g-line, h-line, i-line The exposure light including the three wavelengths is used.

The light amplitude distribution when the exposure light 40 passes through the transmission region 6 of the large phase shift mask 1 and forms an image on the imaging surface on the resist is shown by a broken line 10 in FIG. 1B, and the light intensity distribution is shown in FIG. This is indicated by a broken line 13 in (c). If there is no resolution limit, the light amplitude distribution should be rectangular on the image plane, but the light amplitude distribution has a bell-shaped spread due to the resolution limit of the exposure apparatus (not shown). . On the other hand, the phase of the exposure light transmitted through the phase shift region in FIG. 1A is inverted, and a negative light amplitude distribution is obtained as indicated by the broken line 11 in FIG. The phase shift region 8 is arranged at such a position that the negative light amplitude distribution 11 cancels the light amplitude of the light amplitude distribution 10 in the transmission region 6 and the amplitude of the exposure light is added. A solid line 12 in FIG. 1B shows the amplitude distribution of light that prevents the distribution from spreading. The intensity distribution of the light including the phase shift light corresponding to the amplitude distribution 12 of the light added with the phase shift light is shown by a solid line 14 in FIG. Comparing the light intensity distribution 13 of the transmission region only with the light intensity distribution 14 including the phase shift light, the light intensity is reduced corresponding to the position of the phase shift region 8 and the spread of the light intensity is suppressed. A portion where the light intensity is reduced is indicated by a hatched portion 15. On the other hand, a portion where the light intensity is newly increased is called a side peak on the outside where the light intensity is reduced (FIG. 1 (c) 16). The side peak becomes stronger when the transmittance of the phase shift region is increased, but it must be suppressed to a level at which the resist is not exposed.

The optical characteristics necessary for the phase shift film 5 used in the present invention will be described. The phase shift film 5 is required to have a film thickness that inverts the phase of the exposure light 40, the film thickness d of the phase shift film, the refractive index n of the phase shift film, the wavelength λ of the exposure light, and the exposure light through the phase shift film There is a relationship of Φ = 2π (n−1) d / λ between the phase difference Φ generated through the passage, and the phase difference is inverted because Φ = π. Therefore, the film thickness at which the phase difference is inverted. d is λ / 2 (n−1). Specifically, if the exposure light wavelength λ is 365 nm of i-line and the refractive index n of the phase shift film is 2.55, the thickness of the phase shift film can be calculated as 118 nm. The allowable range of variation in the thickness of the phase shift film is a range of about plus or minus 10 percent with respect to the calculated thickness of the phase shift film. If within this allowable range, the effect of sufficient phase shift as the phase shift film is achieved. Is obtained.

When the exposure light consists of a plurality of peak wavelengths (having three emission line spectra) as in an ultra-high pressure mercury lamp, the thickness of the phase shift film with respect to each peak wavelength is calculated and classified into each peak wavelength. The film thickness of the phase shift film is determined by a sum (weighted average) weighted by the ratio of the energy intensity of the exposure light. For example, when a light source having an energy intensity of Pg, h line Ph, and i line Pi is used as an exposure light source, the thickness of the phase shift film corresponding to each g line corresponds to Dg, h line. If the thickness of the phase shift film is Dh and the thickness of the phase shift film corresponding to the i line is Di, the thickness D of the phase shift film obtained by the weighted average is D = (Pg × Dg + Ph × Dh + Pi × Di) / (Pg + Ph + Pi). Specifically, if Pg = 2, Dg = 141 nm, Ph = 1, Dh = 130, Pi = 3, Di = 118 nm, the thickness D of the phase shift film obtained by weighted averaging is found to be 128 nm. By using the thickness D of the phase shift film obtained by such weighted average, the effect of the phase shift mask can be satisfactorily obtained even with exposure light including a plurality of peak wavelengths.

As a method for obtaining the thickness D of the phase shift film by a weighted average, a method of using a value obtained by multiplying the energy intensity of the exposure light for each peak wavelength by the sensitivity of the resist of the corresponding wavelength can be applied. Even better results are obtained.

The light transmittance of the phase shift film 5 is set to a value that increases the contrast of the exposed pattern within a range in which a side peak due to the effect of the phase shift does not occur. Specifically, the light transmittance of exposure light of the phase shift film 5 is preferably 4% or more and 15% or less. If the transmittance of the phase shift film is 4% or less, the effect of increasing the contrast due to the phase shift is small, and if the transmittance of the phase shift film is 15% or more, the effect of the phase shift is too strong and the sub-peak (side The peak) becomes high, which may cause defects.

As described above, the cross-sectional view of FIG. 1A shows the specific dimensions of each region of the large phase shift mask 1 of the present invention that has the effect of suppressing the spread of the exposure intensity distribution due to the resolution limit of the exposure apparatus. The description will be given with reference. FIG. 1 illustrates an edge-enhanced phase shift mask.

FIG. 1A shows a cross-sectional view of a phase shift mask for exposing a line-and-space space pattern or hole pattern to a positive resist on the exposure surface. The main application of the large phase shift mask of the present invention is pattern formation of a TFT array substrate used for flat display panels such as liquid crystal display devices and EL display devices. The resolution limit of the large projection exposure apparatus used for this pattern formation is about 3 μm, and the large phase shift mask of the present invention provides the exposure pattern contrast for the drawing pattern related to the resolution limit (3 μm). The challenge is to improve. Therefore, the width a of the transmissive region in which the large phase shift mask of the present application exhibits a remarkable effect is 1 μm or more and 6 μm or less.

When the width a of the transmission area is larger than 6 μm, the effect of the large phase shift mask of the present invention is not remarkable because the influence of the resolution limit of the exposure apparatus is small. If the width of the transmissive region is smaller than 1 μm, the exposure pattern cannot be resolved even if the phase shift effect of the present invention is added. Here, the width a of the transmission region is the diameter of the maximum inscribed circle of the target transmission region shape on the transparent substrate plane. If the target transmission region has a rectangular shape, the length of the short side is transparent. The width of the region.

The width of the phase shift region in the present invention is not particularly limited as long as the spread of light intensity in the transmission region can be suppressed and the resist can be exposed to a desired pattern shape.
The width of such a phase shift region is preferably 3.5 μm or less, more preferably 2.5 μm or less, and particularly preferably 2.0 μm or less. This is because if the width of the phase shift region exceeds the above value, the phase shift effect is not within the range, and the effect of increasing the contrast of the exposure pattern may reach its peak. In addition, in the phase shift region located between the transmission region and the light shielding region, the influence of the peak (side peak) of the light intensity distribution due to the light amplitude distribution remaining without being canceled with the light amplitude of the transmission region becomes large, and the phase shift region This is because there is a possibility that the resist reacts with the transmitted light that passes through the resist to cause a dent or the like in the resist pattern shape, making it difficult to make the resist pattern shape a desired shape.
Further, in the present invention, since the spread of light intensity in the transmission region can be suppressed by having the phase shift region, the lower limit of the width of the phase shift region is particularly limited as long as a phase shift film can be formed. Although not limited, it is preferably 0.25 μm or more, more preferably 0.5 μm or more, and particularly preferably 0.8 μm or more. This is because the phase shift region can be provided with good alignment accuracy. Further, when the value is less than the above value, the amount of light whose phase is reversed is reduced, and there is a possibility that the effect is small.
The width b of the phase shift region is in the range of 0.5 μm or more and 2 μm or less, and the effect of phase shift is most remarkable.
Here, the width b of the phase shift region is the shortest distance obtained by measuring the distance from the boundary between the transmission region and the phase shift region to the boundary between the phase shift region and the light shielding region in parallel with the transparent substrate surface.

Here, the resolution limit of the above-described large projection exposure apparatus is that the binary mask can be stably resolved in the exposure area when the binary projection mask is used for exposure with the large projection exposure apparatus. It can be handled in the same manner as the minimum value of the width of the region (hereinafter sometimes referred to as the resolution limit width).
When used with a large projection exposure apparatus, the phase shift mask of the present invention can resolve drawing patterns that are less than the resolution limit width of the binary mask described above.
The width of the drawing pattern of the phase shift mask of the present invention is preferably 100% or less, more preferably 85% or less, more preferably 30% or more with respect to the resolution limit width of the binary mask in a large projection exposure apparatus. Of these, 40% or more is preferable. This is because if the width of the drawing pattern is less than the above range, it may be difficult to resolve the drawing pattern itself. In addition, if the width of the drawing pattern exceeds the above range, it may be difficult to sufficiently exhibit the effect of the phase shift. When the width of the drawing pattern in the phase shift mask is equal to the resolution limit width, the resist shape can be made better than when exposure is performed using a binary mask.
Regarding the width of the drawing pattern, the width of the transmission region of the phase shift mask of the present invention, the width of the phase shift region, and the phase based on the resolution limit width and resist sensitivity inherent in a large projection exposure apparatus. It can be determined by adjusting the transmittance of the shift film.
Here, as shown in FIG. 3B, the width d of the transmission region of the binary mask is set such that the distance from one boundary of the light shielding region adjacent to the one transmission region to the other boundary is parallel to the transparent substrate surface. The shortest distance measured.
Further, the width of the drawing pattern of the phase shift mask refers to the width of the pattern drawn on the resist by the transmission region and the phase shift region.

(Embodiment)
(Constituent material of large phase shift mask)
Specific materials of individual components of the large phase shift mask 1 of the present invention will be described with reference to the cross-sectional view of FIG. The configuration of the large phase shift mask 1 shown in FIG. 1A includes a transparent substrate 2, a light shielding film 3 formed on the transparent substrate 2, and a translucent phase shift formed on the transparent substrate 2. This is a photomask having a structure having a film 4.

The size of the transparent substrate 2 used in the large phase shift mask 1 of the present invention is 350 mm × 350 mm to 1220 mm × 1400 mm and the thickness is 8 mm to 13 mm. As the material, low-expansion glass (aluminoborosilicate glass, borosilicate glass) optically polished or synthetic quartz glass can be used, but synthetic quartz glass having a low coefficient of thermal expansion and high ultraviolet transmittance is preferably used.

The light-shielding film 3 used in the present invention is required to be a material that has a transmittance of 0.1% or less at the exposure wavelength and can be easily patterned. As a material for such a light shielding film, chromium, a chromium compound, a molybdenum silicide compound, and a tantalum compound can be used. However, a good pattern can be formed by wet etching, and chromium or a chromium compound, which has a long history of use, is used as a main component. The light shielding film is preferable. As the chromium compound, chromium nitride is used which has a high light shielding property and requires a thin light shielding film. When comparing a chromium light-shielding film and a chromium nitride light-shielding film, mask blanks using a chromium light-shielding film that is easy to form and highly versatile are easily available and preferable. Specifically, when a thin film of metallic chrome is used as a light shielding film, the film thickness is 70 nm or more in order to make the exposure light transmittance 0.1% or less. On the other hand, when the film thickness is increased, the etching time is increased and the workability is lowered, so that the film thickness is usually 150 nm or less.

The phase shift film 5 used in the present invention is required to be a material that has a transmittance in the range of 4% to 15% at the exposure wavelength and can be easily patterned.

The material of the phase shift film 5 is selected from materials that are translucent and have an appropriate refractive index. Chromium oxynitride (CrON), chromium oxide (CrO), molybdenum silicide oxide (MoSiO), molybdenum silicide oxynitride (MoSiON) tantalum silicide oxide (TaSiO), titanium oxynitride (TiON) can be used. Among these materials, when the oxide or oxynitride of the material constituting the light shielding film 3 is selected as the material of the phase shift film 5, the phase shift film and the light shielding film can be patterned by the same etching equipment and process. This produces the advantage.

Further, by selecting chromium or chromium nitride as the light shielding film 3 and chromium oxide (CrO) or chromium oxynitride (CrON) as the phase shift film 5, the light shielding film 3 and the phase shift film 5 can be processed with the same etching equipment. In addition, both the light-shielding film 3 and the phase shift film 5 can be wet-etched with a second cerium nitrate wet etchant having good pattern processability, which has a great cost advantage.

Here, in a general large projection exposure apparatus, it is difficult to irradiate only parallel light as exposure light, and part of the exposure light often includes light having a predetermined angle. Furthermore, light that diffracts around the pattern edge and reflected light at the boundary of the film come out as stray light. Such stray light is different from the irradiation position in a large projection exposure apparatus and the position actually reaching the resist. There is concern about exposure.
In the present invention, the light shielding region has a structure in which a light shielding film is laminated on a transparent substrate and a phase shift film is laminated on the light shielding film. The phase shift film has a thickness D with a phase difference π. Therefore, for example, when the resist for producing a TFT array substrate or the like is patterned using the phase shift mask of the present invention, the stray light described above may exhibit the following behavior. First, stray light emitted from a large projection exposure apparatus passes through the transparent substrate of the phase shift mask and is reflected by a metal electrode or the like of the TFT array substrate to become reflected light. Next, the reflected light of the stray light enters the phase shift film in the light shielding region, is reflected by the light shielding film, becomes second reflected light, and is emitted from the phase shift film again. Therefore, the phase difference between the reflected light of the stray light incident on the phase shift film in the light shielding region and the second reflected light of the stray light reflected from the light shielding film and emitted from the phase shift layer is 2π. Therefore, since the above-mentioned reflected light and the above-mentioned second reflected light strengthen each other on the surface of the phase shift film, there is a concern that the influence of the stray light on the resist becomes more remarkable.
The above problem is caused by the layer structure of the light shielding region in the present invention.

In the present invention, it is desirable that the light shielding region has an antireflection function from the viewpoint of stray light countermeasures during exposure. The light shielding region 7 used in the present invention has a configuration in which a light shielding film 3 is laminated on a transparent substrate 2 and a phase shift film 5 is laminated on the light shielding film 3, but the phase shift film 5 has a phase difference π. Therefore, the exposure light reflected from the surface of the light shielding film 3 (stray reflected second light) and the reflected light from the surface of the phase shift film 5 (stray reflected light) have a phase difference of 2π and become stronger. It will fit. In order to reduce this influence, an antireflection film 4 made of a translucent film may be provided between the light shielding film and the phase shift film. By having the antireflection film 4, the light reflected from the light shielding film and the light reflected from the antireflection film (light reflected from the light shielding film (second reflected light of stray light) and reflected light of stray light on the surface of the antireflection film) By setting the optical path length so as to weaken each other, it is possible to prevent the phase difference from becoming 2π and strengthening.

The antireflection film in the present invention is not particularly limited as long as it has an antireflection function and can be formed between the light shielding film and the phase shift film in the light shielding region, but a metal film, a metal compound film, etc. It can be used suitably.
Examples of the material for the antireflection film include chromium oxide (CrO), chromium oxynitride (CrON), chromium nitride (CrN), titanium oxide (TiO), tantalum oxide (TaO), and nickel aluminum oxide (NiAlO). Among them, chromium oxide (CrO) and chromium oxynitride (CrON) can be preferably used.

The thickness of the antireflection film is designed to have an optical path length so that the light reflected by the light shielding film and the light reflected by the antireflection film are weakened.
The thickness of such an antireflection film is such that the phase difference between the light reflected from the light shielding film and the light reflected from the antireflection film is π ± 10 because light reflected from the light shielding film passes through the antireflection film. The thickness is preferably in the range of π ± 5, and in particular, the thickness is preferably in the range of π ± 5, and particularly preferably π.
This is because the light reflected by the light-shielding film and the light reflected by the antireflection film can be suitably weakened, and problems due to stray light can be suitably prevented.

The specific thickness of the antireflective film is appropriately selected depending on the material of the antireflective film and is not particularly limited, but is in the range of 0.01 μm to 0.1 μm, and in particular, 0. It is preferably in the range of 02 μm to 0.05 μm. If it is less than the above range, it may be difficult to form the antireflection film with a uniform thickness. If it exceeds the above range, it takes a lot of time and cost to form the antireflection film. Because there is a possibility.

Further, as the antireflection film, in addition to the film that adjusts the phase of transmitted light, for example, a metal film or the like having a roughened surface and imparting a function of diffusing light may be used.

As a method for preventing the reflection of the surface of the phase shift film 5, a semitransparent low reflection film can be provided on the surface of the phase shift film 5. In particular, when the phase shift film 5 is made of chromium oxynitride, the surface may contain metallic luster. In this case, a low reflection layer made of chromium oxide is effective.

(Production method)
2 (a) to 2 (f) are diagrams for explaining a manufacturing process of the large phase shift mask 1 of the present invention shown in FIG. 1 (a).

In order to manufacture the large phase shift mask 1 of the present embodiment, first, a photomask blank 20 is prepared in which a light shielding film 3 is laminated on a transparent substrate 2 and further an antireflection film 4 is laminated as required (FIG. 2 (a)). The transparent substrate 2 is usually made of optically polished synthetic quartz having a thickness of 8 mm to 12 mm. If the light shielding film 3 of the photomask blank 20 is a chromium film or a chromium nitride film, it is formed by sputtering. If the antireflection film is chromium oxide, it is similarly formed by sputtering. Blanks in which the light-shielding film is chromium and the antireflection film is chromium oxide are the most common blanks, and commercial products can be easily obtained.

Next, the light shielding film 3 and the antireflection film 4 of the photomask blank 20 are patterned according to a normal method (first pattern formation step). That is, a photosensitive resist corresponding to the exposure wavelength of the laser beam drawing apparatus is applied on the light shielding film 3 or the antireflection film 4 and baked for a predetermined time after the application to form a light shielding film resist film having a uniform thickness. . Next, a pattern of the light shielding region 7 is drawn on the resist film for light shielding film by a laser drawing apparatus and developed to form a resist 16 for light shielding film (FIG. 2B). Usually, the light shielding region 7 is a region obtained by removing the transmission region 6 and the phase shift region 8 from the entire effective region of the mask. Further, if necessary, an alignment mark is formed of a light shielding film and used for alignment with the phase shift region pattern.

Next, the light shielding film exposed from the light shielding film resist 16 is removed by etching, the remaining resist is peeled and removed, and the substrate 21 with the light shielding film patterned in the shape of the light shielding region 7 is obtained. Is obtained (FIG. 2 (c)). Etching of the light-shielding film 3 can be performed by wet etching or dry etching. However, as the photomask used in the flat display is increased in size as described above, dry etching increases the cost of the etching apparatus. In addition, since it is difficult to control the uniformity of etching in a large area, wet etching is preferable in terms of cost. If the light-shielding film 3 is a chromium-based film, the pattern can be satisfactorily formed with a wet etchant obtained by adding perchloric acid to ceric ammonium nitrate. If the material of the antireflection film 4 is a chromium-based material such as chromium oxide, a pattern can be formed by etching with the wet etchant simultaneously with the chromium-based light shielding film.

In the present embodiment, after the pattern formation process of the light shielding film 3, the patterned light-shielding film-attached substrate 21 is inspected, and if necessary, a process of correcting defects can be performed.

Next, the phase shift film 5 is formed on the entire surface of the patterned light-shielding film-attached substrate 21 (FIG. 2D). Here, the phase shift film 5 is preferably made of the same material as the light shielding film 3. If the light shielding film 3 is made of a chromium-based material as described above, the phase shift film 5 contains one or more elements such as oxygen, nitrogen, and carbon in chromium, has a relatively high refractive index, and has a predetermined value. The component ratio of the material is selected so that the light transmittance is within the range. Specifically, the constituent ratio of each element is selected in chromium oxide, chromium oxynitride, and chromium oxynitride carbide.

The film formation of the phase shift film 5 is performed by a vacuum film formation method such as a sputtering method, similar to the method of forming the chromium light shielding film.

Next, in the second pattern formation step, the phase shift film 5 is patterned by aligning with the light shielding region 7 which is the lower light shielding film pattern. That is, a photosensitive resist corresponding to the exposure wavelength of the laser beam drawing apparatus is applied on the phase shift film 5 and baked for a predetermined time after the application to form a resist film for a phase shift film having a uniform thickness. Next, the pattern of the area | region which combined the phase shift area | region 8 and the light-shielding area | region 7 is drawn on the resist film for phase shift films with a laser beam drawing apparatus. Subsequently, the exposed phase shift film resist is developed to obtain a patterned phase shift film resist 17 (FIG. 2E).

Next, the phase shift film 5 exposed from the phase shift film resist 17 is removed by etching to obtain a phase shift film patterned into a shape in which the phase shift region 8 and the light shielding film pattern 7 are combined. Here, if the phase shift film is formed of a material containing at least one of oxygen, nitrogen, and carbon in chromium, pattern processing is performed by the same wet etching as the etching of the light shielding film 3 formed of chromium or a chromium compound. As described above, the cost advantage of the pattern processing process is great.
Next, the remaining resist film for the phase shift film is peeled off and removed to complete a large phase shift mask (FIG. 2 (f)).
The method for manufacturing the phase shift mask according to the embodiment of the present invention has been described above with reference to FIG. Particularly in this manufacturing method, if the light shielding film 3 is made of chromium and the phase shift film 5 is made of a chromium compound containing at least one of oxygen, nitrogen, and carbon, a commercially available starting material for the manufacturing process is used. A chrome hard mask can be used, and the etching process is all wet etching, resulting in a great manufacturing cost merit.

(Other)
The phase shift mask of the present invention is used for patterning a resist for pattern formation of the TFT array substrate or the like.
The resist used together with the phase shift mask of the present invention can be appropriately selected depending on the electrode material of the TFT substrate, the developer, the projection type exposure machine, etc., and is not particularly limited.
For example, when using an exposure machine manufactured by Nikon as an exposure machine, and using AZ1500 as a resist and AZ300MIF as a developer, the influence of exposure light on a portion of the phase shift mask having a transmittance of 5% or less can be reduced. That is, since the resist can be hardly drawn by light having an exposure intensity of 5% or less, it is difficult to react to the side peak in the exposure intensity distribution, and the resist can be satisfactorily patterned.

The thickness of the resist is not particularly limited as long as it can be patterned into a desired shape using the phase shift mask of the present invention, but is within the range of 1.0 μm to 10.0 μm. It is preferably in the range of 2 μm to 5.0 μm, particularly in the range of 1.5 μm to 4.0 μm. By setting the thickness of the resist within the above range, a resist pattern having a desired shape can be formed using the phase shift mask of the present invention.

Note that the resist used together with the phase shift mask of the present invention is not limited to the above.

Note that the present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

(About contrast of exposure intensity distribution)
FIG. 3 is an explanatory diagram comparing the effect of improving the contrast of the exposure intensity distribution of the large phase shift mask (Example 1) according to the present invention with that of a conventional binary mask (Comparative Example 1). 3A is a plan view showing a line and space pattern of a large phase shift mask (Example 1) according to the present invention, and FIG. 3B is a line and space pattern of a conventional binary mask (Comparative Example 1). FIG. 3C is a plan view showing the space pattern, and FIG. 3C is a diagram for comparing the exposure intensity distributions on the imaging planes of the masks shown in FIGS. 3A and 3B.

Table 1 is a table comparing the effect of improving the contrast of the exposure intensity distribution of the large phase shift mask (Example 1) according to the present invention with the conventional binary mask (Comparative Example 1).

3A is a line-and-space pattern with a pitch of 4 μm and the width a of the transmission region 6 is 3 μm. The width b of the phase shift region 8 provided adjacent to both sides of the transmission region 6 is 0.4 μm, the transmittance is 5.2%, and the phase is inverted by π (180 degrees). The width of the light shielding region 7 is 0.2 μm and the transmittance is 0%. The transmittance of each region is calculated with the transmittance of the transmissive region 6 being 100%.

The pattern of the binary mask which is Comparative Example 1 in FIG. 3B is a line and space pattern with a pitch of 4 μm, the width d of the transmission region is 3 μm, and the width e of the light shielding region is 1 μm.

FIG. 3 (c) is a graph showing the result obtained by simulating the exposure result by the exposure apparatus, and the light source of the exposure apparatus was calculated using a three-wavelength mixed light source of g-line, h-line and i-line. The vertical axis of the graph is displayed by normalizing the maximum value of the exposure light intensity of the transmission region on the imaging plane to 1, and the horizontal axis of the graph indicates the position on the imaging plane. An exposure light intensity distribution curve 31 shows the exposure light intensity distribution of the large phase shift mask at a position corresponding to the AA cross section of FIG. The exposure light intensity distribution curve 32 of the binary mask at a position corresponding to the BB cross section of FIG.

The maximum value of the light intensity distribution of the large phase shift mask exposure light intensity distribution curve 31 shown in FIG. 3C is 0.747, the minimum value is 0.324, and the contrast that is the difference between the maximum value and the minimum value is 0. 423. On the other hand, the maximum value of the light intensity distribution of the exposure light intensity distribution curve 32 of the conventional binary mask is 0.782, the minimum value is 0.399, and the contrast that is the difference between the maximum value and the minimum value is 0.383. Met. That is, the contrast of the exposure light on the imaging surface of the conventional binary mask is 0.383, whereas the contrast of the exposure light of the large phase shift mask of the present invention is 0.423, which increases the 0.04 contrast. In terms of contrast ratio, an improvement of about 10% was observed. The results are summarized in the effect of the large phase shift mask in Table 1.

From the above exposure simulation results, the present invention can appropriately arrange a phase shift region in a large mask, improve the contrast of the exposure intensity distribution on the imaging surface, and stably form a finer pattern. Can do.

(Relationship between resolution limit of exposure tool and drawing pattern of phase shift mask)
<Production of phase shift mask>
A commercially available photomask blank in which a synthetic quartz (transparent substrate) having a thickness of 10 mm, a chromium film (light-shielding film) having a thickness of 100 nm, and a chromium oxide film (antireflection film) having a thickness of 25 nm are laminated in this order is prepared. A photosensitive resist adapted to the above was applied and baked for a predetermined time after the application to form a resist film for a light-shielding film having a uniform thickness. Next, a light shielding region pattern was drawn on the light shielding film resist film by a laser drawing apparatus and developed to form a light shielding film resist.
Next, the antireflection film and the light shielding film exposed from the resist for the light shielding film are removed by etching using a wet etchant obtained by adding perchloric acid to ceric ammonium nitrate, and the remaining resist is peeled and removed. Thus, a substrate with a light shielding film and an antireflection film patterned in the shape of the light shielding region was obtained.
Next, a chromium oxynitride film (phase shift film) was formed on the entire surface of the patterned light-shielding film and antireflection film-coated substrate by a sputtering method.

Next, in the second pattern formation step, the resist film for phase shift film was formed by the same formation method as the resist for light shielding film by aligning with the light shielding region which is the light shielding film pattern of the lower layer. Next, a pattern of a region in which the phase shift region and the light-shielding region are combined is drawn on the phase shift film resist film by a laser beam drawing apparatus and then developed to obtain a patterned phase shift film resist.

Next, the phase shift film exposed from the resist for the phase shift film is removed by etching in the same manner as the light shielding film and the antireflection film described above, and pattern processing is performed so that the phase shift region and the light shielding film pattern are combined. A phase shift film was obtained. Next, the remaining resist film for the phase shift film was peeled off and removed. Through the above steps, the transmission region (line width 1.9 μm), the phase shift region (line width 2.0 μm), and the light shielding region are arranged. In the light shielding region, the antireflection film and the phase shift film are arranged in this order on the light shielding film. A laminated large phase shift mask was obtained.

<Preparation of resist pattern>
Using the above-mentioned phase shift mask, using a Nikon exposure machine with a resolution limit of 3 μm, pattern exposure was performed on a 1.6 μm thick resist (AZ1500) formed on a glass substrate, and development processing was performed. A resist pattern of 1.9 μm could be formed.

(About the width of the phase shift region in the phase shift mask)
FIG. 6 is a plan view showing a pattern of a large phase shift mask according to the present invention, FIG. 7 is a view showing an exposure intensity distribution on the image plane of the large phase shift mask shown in FIG. 6, and FIG. 7 is an enlarged view of a portion C, and FIG. 9 is an enlarged view of a portion D of FIG.
As a large phase shift mask, the width of the transmission region is 5 μm, and the width b of the phase shift region is 0.25 μm (Example 3), 0.5 μm (Example 4), 0.75 μm (Example 5), 1 0.0 μm (Example 6), 1.5 μm (Example 7), 2.0 μm (Example 8), 2.5 μm (Example 9), 3.0 μm (Example 10), 3.5 μm (Example) 11) and 4.0 μm (Example 12), the simulation was performed on the exposure intensity distribution (light intensity) by the Nikon exposure machine. The simulation conditions other than the large phase shift mask pattern were the same as in Example 1. The results are shown in FIGS.
The smaller the exposure intensity shown in FIG. 8, the sharper the waveform shown in FIG. 7, but the phase shift effect at the position of the pattern edge of the large phase shift mask is the width of the phase shift region. When the thickness exceeds 2.0 μm, no further effect was observed (the phase shift effect reached its peak).
Also, as shown in FIG. 9, the side peak value increased as the width of the phase shift region increased.
In the present invention, the width of the phase shift region can be set so that the side peak does not affect the resist according to the sensitivity of the resist.
The width of such a phase shift is preferably set to a width at which the side peak exposure intensity is 5% or less, that is, from 0.25 μm to 3.5 μm, based on the results of the resist used when forming the TFT array substrate. .

DESCRIPTION OF SYMBOLS 1 Large phase shift mask 2 Transparent substrate 3 Light shielding film 4 Antireflection film 5 Phase shift film 6 Transmission area 7 Light shielding area 8 Phase shift area 10 Light amplitude distribution of transmission area 11 Light amplitude distribution of phase shift area 12 Including phase shift effect Light amplitude distribution 13 Light intensity distribution in transmission region 14 Light intensity distribution including phase shift effect 15 Effect of phase shift region 16 Resist formed in pattern of light shielding film 17 Formed in pattern of phase shift region and light shielding film Resist 20 Photomask blanks 21 Photomask blanks with light-shielding film patterned 30 Binary mask 31 Light intensity distribution of large phase shift mask 32 Light intensity distribution of binary mask 40 Exposure light

Claims

A transparent substrate, a light shielding film formed on the transparent substrate, and a translucent phase shift film formed on the transparent substrate,
A transmission region where the transparent substrate is exposed; a light shielding region where the light shielding film is provided on the transparent substrate; and a phase shift region where only the phase shift film is provided on the transparent substrate, And the phase shift region has an adjacent pattern, the phase shift region is adjacently disposed between the transmission region and the light shielding region, and the exposure light transmitted through the phase shift region is the transmission region. In the phase shift mask whose phase is reversed with respect to the exposure light transmitted through
The light shielding film includes chromium or a chromium compound as a main component, the phase shift film includes chromium oxide or chromium oxynitride as a main component, and a phase shift film is stacked on the light shielding film in the light shielding region. Large phase shift mask.
The large phase shift mask according to claim 1, further comprising an antireflection film between the light shielding film and the phase shift film in the light shielding region.
3. The large phase shift mask according to claim 1, wherein the phase shift region has a width in a range of 0.25 μm to 3.5 μm.
The large phase shift mask according to any one of claims 1 to 3, wherein the narrowest part of the transmission region has a width in a range of 1 µm to 6 µm.
The large phase shift mask according to any one of claims 1 to 4, wherein the light transmittance of the phase shift film with exposure light is 4% or more and 15% or less.
A transparent substrate; a light-shielding film formed on the transparent substrate; a translucent phase shift film formed on the transparent substrate; and a transparent region where the transparent substrate is exposed; and the transparent substrate on the transparent substrate. A light-shielding region provided with a light-shielding film; and a phase-shift region in which only the phase-shift film is provided on the transparent substrate, wherein the transmission region and the phase-shift region have adjacent patterns, and the transmission region A phase shift area adjacent to the light shielding area, and the phase of the exposure light transmitted through the phase shift area is reversed with respect to the exposure light transmitted through the transmission area A method of manufacturing a phase shift mask for manufacturing
A step of preparing a blank with a photosensitive resist, which is obtained by applying a photosensitive resist to a blank in which a light-shielding film made of chromium or a chromium compound is laminated on one surface of the transparent substrate;
A process of exposing a desired pattern to a blank with a photosensitive resist with a drawing apparatus, developing it, performing wet etching, removing the photosensitive resist, and patterning a light-shielding film;
Forming a phase shift film made of a chromium compound on the transparent substrate and the patterned light-shielding film;
From the step of applying a photosensitive resist to the formed phase shift film, exposing and developing a desired pattern with a drawing apparatus, performing wet etching, removing the photosensitive resist, and patterning the phase shift film A method for producing a large phase shift mask.
A transparent substrate; a light-shielding film formed on the transparent substrate; a translucent phase shift film formed on the transparent substrate; and a transparent region where the transparent substrate is exposed; and the transparent substrate on the transparent substrate. A light-shielding region provided with a light-shielding film; and a phase-shift region in which only the phase-shift film is provided on the transparent substrate, wherein the transmission region and the phase-shift region have adjacent patterns, and the transmission region And a phase shift region adjacent to the light shielding region, and the exposure light transmitted through the phase shift region is inverted in phase with respect to the exposure light transmitted through the transmission region. In the region, the phase shift film is manufactured by stacking the phase shift film on the light shielding film, and producing a phase shift mask further including an antireflection film between the light shielding film and the phase shift film in the light shielding region. A law,
On one surface of the transparent substrate, a photosensitive resist was applied to a blank laminated in the order of a light shielding film mainly composed of chromium and an antireflection film mainly composed of chromium oxide or chromium oxynitride. A step of preparing blanks with a photosensitive resist;
Exposing a desired pattern to a blank with a photosensitive resist with a drawing apparatus, developing, wet etching, removing the photosensitive resist, and patterning the light-shielding film and the antireflection film; and
Forming a phase shift film made of a chromium compound on the transparent substrate and the patterned light shielding film and the antireflection film;
From the step of applying a photosensitive resist to the formed phase shift film, exposing and developing a desired pattern with a drawing apparatus, performing wet etching, removing the photosensitive resist, and patterning the phase shift film A method for producing a large phase shift mask.