JP2013061670A - Gradation mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gradation mask, with which manufacturing processes of a display device can be simplified and a pattern is advantageously formed.SOLUTION: The gradation mask for manufacturing a display device to be used for manufacturing a display device comprises a transparent substrate, a light-shielding film and a translucent film having a function of controlling transmittance, layered in a random order, and includes a light-shielding region where the light-shielding film is formed on the transparent substrate, a translucent region where only the translucent film is formed on the transparent substrate, and a transmissive region where neither the light-shielding film nor the translucent film is formed on the transparent substrate. The translucent film comprises a metal film. The gradation mask for manufacturing a display device includes no etching stopper film.

Description

  The present invention relates to a gradation mask suitably used for halftone exposure in the manufacturing process of a display device or the like.

  For example, a reflow method or an ashing method is disclosed as a pattern forming method for reducing the number of lithography steps of a display device such as a liquid crystal display device or an organic electroluminescence display device (see, for example, Patent Document 1 and Patent Document 2). In addition, the above-mentioned patent document discloses a photomask (slit mask) having a minute slit below the resolution limit of exposure light and a photomask (gradation mask) having a gradation with respect to the exposure light. .

In the slit mask, a general light shielding film such as a chromium film that substantially shields exposure light is used, and a fine slit below the resolution limit of the exposure machine is disposed in the light shielding film (see, for example, Patent Document 3). Since the slit of the mask has a size not larger than the resolution limit, the mask itself does not form an image on the resist, and the exposure light according to the size is transmitted to the area including the surrounding non-opening region. For this reason, the slit mask functions as if a translucent film exists in the area where the slit is formed and the area including the periphery of the area.
However, since this slit needs to be below the resolution limit, it is natural that the slit needs to be finished to a size smaller than the mask main body pattern, resulting in a large burden on mask manufacturing. It was. Furthermore, in order to make a wide area semi-transparent, it is necessary to arrange many slits, so that the pattern data capacity increases, and there arises a problem that the load on the pattern formation process and the pattern defect inspection process also increases. -There was a problem that the inspection time was increased and the mask manufacturing cost was increased.

  On the other hand, the gradation mask uses a light-shielding film that substantially shields exposure light and a translucent film that transmits exposure light at a desired transmittance, and a light-transmissive area that does not transmit light. And a semi-transparent region in which the amount of transmitted light is adjusted (see, for example, Patent Document 4). In order to produce this mask, a mask pattern is made using a dedicated mask blank in which a translucent film and a light shielding film are laminated on a transparent substrate. This gradation mask is advantageous in that it is not necessary to arrange fine slits unlike the slit mask.

In a gradation mask, the resist film thickness after development can be controlled in two stages by controlling the amount of transmitted light according to regions having different transmittances. For example, it is possible to simultaneously form columnar spacers and liquid crystal alignment function protrusions in a color filter for a liquid crystal display device by performing batch exposure using a gradation mask (see, for example, Patent Document 5).
The gradation mask described in Patent Document 5 has a transmittance of 5% or less at 300 nm and 45% or more at 380 nm, cuts a short wavelength range (about 300 nm to 350 nm) of exposure light, and a long wavelength range (350 nm to 350 nm). Only about 450 nm). However, when only the long wavelength region is used, the energy is lower than when the short wavelength region is used, so that there is a problem that the curing speed is slow and the exposure takes time.

  In Patent Documents 4 and 5, as a semi-transparent film of a gradation mask, a chromium oxide film, a chromium nitride film, a chromium oxynitride film, a chromium fluoride film, an indium tin oxide film, and an oxide film containing Ti and W An oxide film containing Ti and Mo is used. As described above, it is a mainstream to use a film made of a metal oxide or nitride as the translucent film. On the other hand, no example using a metal film as a translucent film has been reported.

Japanese Patent No. 3415602 JP 2000-66240 A JP 2002-196474 A JP 2002-189280 A JP-A-2005-84366

  The present invention has been made in view of the above problems, and has as its main object to provide a gray scale mask that is advantageous for forming a pattern while simplifying the manufacturing process of a display device.

  In order to achieve the above object, the present invention provides a light shielding region in which a transparent substrate, a light shielding film, and a translucent film having a transmittance adjusting function are stacked in random order, and the light shielding film is provided on the transparent substrate. A translucent region in which only the translucent film is provided on the transparent substrate, and a transmissive region in which neither the light-shielding film nor the translucent film is provided on the transparent substrate, Provided is a gradation mask characterized in that the transparent film is a metal film.

In general, since metals are bonded via free electrons, there is no band gap that causes light absorption. Therefore, there is no characteristic absorption, and the transmittance is often in a certain range from the ultraviolet light region to the visible light region. In contrast, a metal oxide has a relatively small absorption coefficient, and the absorption coefficient approaches zero as the wavelength becomes longer (ultraviolet / visible region). Therefore, the longer the wavelength, the higher the transmittance. Metal nitrides and metal carbides also show the same tendency as metal oxides. Therefore, by using a metal film as the translucent film, a gradation mask including a translucent film having desired transmittance characteristics can be obtained.
In such a gradation mask, both the long wavelength region and the short wavelength region of the exposure light can be used effectively, so that the exposure time can be shortened. For example, when forming a pattern using a negative resist, the transmittance ratio of the transmissive region and the semi-transparent region can be regarded as the film thickness ratio of the resist after exposure of the transmissive region and the semi-transparent region, Resist film thickness can be easily controlled.

  In the said invention, it is preferable that the said semi-transparent film | membrane and the said light shielding film are chromium films. This is because when the semi-transparent film and the light-shielding film are chromium films, the semi-transparent film and the light-shielding film can be simultaneously patterned using the same etchant when the gradation mask is manufactured. In addition, the chromium film is excellent in mechanical strength, and is stable without light-retarding, so that it can be a gradation mask that can withstand long-time use.

Furthermore, the present invention provides a gradation mask for manufacturing a display device, wherein the above-described gradation mask is used for manufacturing a display device.
Since the gradation mask for manufacturing a display device according to the present invention uses the above-described gradation mask, the manufacturing process of the display device can be simplified, and the exposure time during pattern formation can be shortened. It is.

  In the present invention, a gradation mask including a translucent film having a desired transmittance characteristic can be obtained by using a metal film as the translucent film. Patterns with different heights and shapes can be simultaneously formed by batch exposure using such a gradation mask, and the manufacturing process can be simplified. Further, by using the gradation mask of the present invention, the short wavelength region of the exposure light can be used for the resist curing reaction, and the exposure time can be shortened.

It is a schematic sectional drawing which shows an example of the gradation mask of this invention. It is process drawing which shows the example which forms the spacer in a liquid crystal display device using the gradation mask of this invention. It is a graph which shows an example of the spectrum of the semi-transparent film | membrane in this invention. It is a top view which shows an example of the gradation mask of this invention. It is a top view which shows the other example of the gradation mask of this invention. It is the sectional view on the AA line of FIG. It is sectional drawing which shows an example of the spacer and protrusion for alignment control in the liquid crystal display device formed using the gradation mask of this invention. FIG. 6 is a sectional view taken along line B-B in FIG. 5. It is sectional drawing which shows an example of the spacer and overcoat layer in the liquid crystal display device formed using the gradation mask of this invention. It is process drawing which shows an example of the manufacturing method of the gradation mask of this invention. It is process drawing which shows the other example of the manufacturing method of the gradation mask of this invention. FIG. 10 is a process diagram illustrating an example of manufacturing a thin film transistor using the gradation mask of the present invention. 6 is a graph showing spectral spectra of semi-transparent films in Example 1 and Comparative Example 1.

  Hereinafter, the gradation mask and the gradation mask for manufacturing a display device of the present invention will be described in detail.

A. Gradation mask The gradation mask of the present invention comprises a light shielding region in which a transparent substrate, a light shielding film, and a translucent film having a transmittance adjusting function are stacked in random order, and the light shielding film is provided on the transparent substrate. A translucent region in which only the semitransparent film is provided on the transparent substrate, and a transmissive region in which neither the light-shielding film nor the semitransparent film is provided on the transparent substrate, and the semitransparent The film is a metal film.

The gradation mask of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view showing an example of the gradation mask of the present invention. As illustrated in FIG. 1, the gradation mask 1 is obtained by laminating a translucent film 3 and a light shielding film 4 in this order on a transparent substrate 2. This translucent film 3 has a transmittance adjusting function. The light shielding film 4 does not substantially transmit exposure light. In the gradation mask 1, the translucent film 3 and the light shielding film 4 are formed in a pattern on the transparent substrate 2, and the light shielding region 11 in which the light shielding film 4 is provided on the transparent substrate 2 and the transparent substrate 2. A semi-transparent region 12 in which only the semi-transparent film 3 is provided and a transmissive region 13 in which neither the semi-transparent film 3 nor the light-shielding film 4 is provided on the transparent substrate 2 are mixed.

  Next, an example of a method of forming a spacer in a liquid crystal display device using the gradation mask 1 shown in FIG. 1 is shown in FIG. In the gradation mask 1, the exposure light 15 is transmitted through the transparent substrate 2 in the transmission region 13, and the exposure light 15 is transmitted through the transparent substrate 2 and the semitransparent film 3 in the semitransparent region 12. Since exposure light having a normal wavelength is irradiated from the transmission region 13, a pattern almost corresponding to the mask pattern shape is formed. On the other hand, the exposure light irradiated from the semi-transparent region 12 is transmitted with a predetermined transmittance according to the wavelength because the translucent film 3 is adjusting the transmittance. Therefore, when pattern exposure is performed with the same exposure amount in the transmissive region 13 and the semi-transparent region 12, the spacer 16a having a height corresponding to the resist thickness before exposure is formed in the transmissive region 13, and in the semi-transparent region 12, the spacer 16a A spacer 16b lower than the height is formed. In this way, patterns with different heights can be obtained simultaneously with a single gradation mask by batch exposure using the gradation mask of the present invention.

  In general, since metals are bonded via free electrons, there is no band gap that causes light absorption. Therefore, there is no characteristic absorption, and the transmittance is often in a certain range from the ultraviolet light region to the visible light region. FIG. 3 shows an example of a spectral spectrum of the translucent film in the present invention. As illustrated in FIG. 3, the translucent film has a transmittance in a certain range at a wavelength of 250 nm to 600 nm. That is, the transmissivity of the translucent film is substantially constant regardless of the wavelength. Therefore, by using a metal film as the translucent film, a gradation mask including a translucent film having desired transmittance characteristics can be obtained.

  In a translucent region provided with a translucent film having such transmittance characteristics, not only the long wavelength region (about 350 nm to 450 nm) of exposure light but also the short wavelength region (about 300 nm to 350 nm) has a predetermined transmittance. Therefore, the short wavelength region is also used for the resist curing reaction.

  Light in the short wavelength region has the advantages of high energy and fast curing speed, and the exposure time can be shortened by effectively using the light in the short wavelength region as described above. Moreover, since exposure in a short wavelength region tends to harden the resist from the surface, diffusion of impurities from the inside of the resist can be suppressed. Furthermore, exposure in a long wavelength region is effective in forming patterns having different heights as described above, because light tends to reach the deep part to cure the resist. Therefore, the gradation mask of the present invention can effectively use a wide wavelength range, which is advantageous for pattern formation.

In general, the exposure apparatus has different emission spectra (wavelength range, peak wavelength, peak intensity ratio, peak half width, etc.) depending on the type. For this reason, it is necessary to design the transmittance of the gradation mask in accordance with the exposure apparatus to be used so that the exposure amount is appropriate for forming the target pattern.
Since the translucent film in the present invention is a metal film, the transmittance from the ultraviolet light region to the visible light region tends to be in a certain range, and the transmittance is within a certain range in the entire exposure wavelength region. Therefore, for example, when a high-pressure mercury lamp is used in the exposure apparatus, for example, in FIG. 3, the transmittance at 300 nm is 39%, the transmittance at 365 nm (I line) is 37%, and the transmittance at 436 nm (G line) is 35. %, And the transmittance is within a certain range (about 33% to 40%) in the entire wavelength range (250 nm to 600 nm). Therefore, when a negative resist is used as illustrated in FIG. 2, the transmissivity (%) at each wavelength of the translucent film: transmissivity 100 (%) ≈the average transmissivity of the translucent area: the average of the transmissible area Transmittance≈resist thickness after exposure of semi-transparent area: resist thickness after exposure of transmission area. That is, by adjusting the transmittance at a certain wavelength, the transmittance can be adjusted within a predetermined range over the entire exposure wavelength range, and the resist thickness after exposure can be controlled. Thus, in the gradation mask of the present invention, the resist film thickness can be easily controlled, and various resist thicknesses can be easily designed.

  On the other hand, for example, a metal oxide film generally exhibits transmittance characteristics such that transmittance increases as the wavelength increases. In such a metal oxide film, the transmittance at 300 nm is 27% at 436 nm (G line) even though the transmittance at 365 nm (I line) is 37% as in the semitransparent film illustrated in FIG. Even if the transmittance at a certain wavelength is adjusted, for example, the transmittance is 48%, the transmittance does not fall within a certain range over the entire exposure wavelength region. Since the film thickness of the resist varies depending on which wavelength greatly contributes to the curing reaction of the resist, it is difficult to control the film thickness of the resist with a gradation mask having a metal oxide film as a translucent film.

  Further, as described above, the translucent film in the present invention tends to have a constant transmittance over the entire exposure wavelength range, and the transmittance ratio between the wavelengths is approximately the same. The tone mask has an advantage that an exposure apparatus is not selected. For example, as shown in FIG. 3, when each transmissivity of the translucent film at 300 nm, 365 nm (I line), 405 nm (H line), and 436 nm (G line) is in the range of 35% to 40%, The transmittance ratio is approximately 1: 1: 1: 1. In this case, for example, if there is an exposure apparatus with different intensity ratios of I-line, H-line, and G-line, the transmittance ratio between the wavelengths is approximately the same. The exposure amount in the translucent region with respect to the exposure amount in the region is in the range of 35% to 40%. Thus, the gradation mask of the present invention can be applied regardless of the difference in the emission spectrum of the exposure apparatus (wavelength range, peak wavelength, peak intensity ratio, peak half width, etc.).

On the other hand, for example, the above-described metal oxide film generally exhibits transmittance characteristics such that the transmittance increases as the wavelength becomes longer, and thus the transmittance ratio between the wavelengths is different. For example, when each transmittance of a metal oxide film at 300 nm, 365 nm (I line), 405 nm (H line), and 436 nm (G line) is 10%, 20%, 35%, and 40%, the transmittance of each wavelength The ratio is 1: 2: 3.5: 4. In this case, for example, if there is an exposure apparatus with different intensity ratios of I-line, H-line, and G-line, the transmissivity ratio between each wavelength is different. The amount of exposure in the area is different. Therefore, in a gradation mask having such a metal oxide film as a semi-transparent film, the transmittance at each wavelength must be designed so that an appropriate exposure amount is obtained according to the exposure apparatus to be used.
Thus, the gradation mask of the present invention is also advantageous in that it can be applied without depending on the exposure apparatus.

In the gradation mask of the present invention, a transparent substrate, a light shielding film, and a semitransparent film are laminated in any order. For example, as shown in FIG. 1, when the gradation mask 1 in which the transparent substrate 2, the semi-transparent film 3, and the light-shielding film 4 are laminated in this order is produced, a semi-transparent film is formed on the transparent substrate and laser light or the like is formed. The pattern of the semi-transparent film can be drawn by the above, and a plurality of alignment marks used for alignment can be drawn and arranged at the time of patterning the light shielding film.
In general, metals have a relatively high reflectance, and metal oxides, metal nitrides, metal carbides, and the like have a relatively low reflectance. For this reason, when the translucent film is a metal film, there is an advantage that the detection of the alignment mark is easy. That is, the alignment becomes easy in the second mask pattern plate making.
Hereinafter, each configuration of the gradation mask of the present invention will be described.

1. Translucent film The translucent film used in the present invention is a metal film and has a transmittance adjusting function.
The metal film is not particularly limited as long as it has a transmittance adjusting function, and examples thereof include films of chromium, molybdenum silicide, tantalum, aluminum, silicon, nickel, and the like. These metal films may contain a trace amount of oxygen, nitrogen, or the like as long as they have a transmittance adjusting function.
From the advantage that the semi-transparent film and the light-shielding film can be patterned by the same etching equipment and process, the semi-transparent film is preferably a film made of a material similar to the light-shielding film, that is, a material containing the same kind of metal. As will be described later, since the light shielding film is preferably a chromium film, the translucent film is preferably a chromium film. Since the chromium film is excellent in mechanical strength and is stable without light-retarding, the gradation mask of the present invention has an advantage that it can withstand long-time use.
As described above, this chromium film may contain a small amount of oxygen, nitrogen, etc. In this case, the chromium content in the film is preferably 80% or more, particularly 95% or more. Is preferred. This is because a translucent film satisfying suitable transmittance characteristics described later can be obtained.

  As the metal film, a molybdenum silicide film and a tantalum film are also preferably used. This tantalum film may contain a very small amount of oxygen or nitrogen, like the chromium film.

  The translucent film in the present invention preferably has a transmittance within a certain range from the ultraviolet light region to the visible light region. Specifically, the transmittance distribution in the wavelength range of 300 nm to 450 nm of the translucent film is preferably 7% or less, and particularly preferably 5% or less. For example, when a high-pressure mercury lamp is used for the exposure apparatus, the end of the emission spectrum is approximately 300 nm, the wavelength of I-line is 365 nm, the wavelength of H-line is 405 nm, and the wavelength of G-line is 436 nm. If the transmittance distribution within the range of 300 nm to 450 nm including the above is within the above range, both the long wavelength range (about 350 nm to 450 nm) and the short wavelength range (about 300 nm to 350 nm) of the exposure light are translucent with almost constant transmittance. Since it passes through the film, it is advantageous for pattern formation for the reasons described above, and the resist film thickness can be easily controlled. On the other hand, if the transmittance distribution in the range of 300 nm to 450 nm exceeds the above range, the transmittance may not be in a certain range over the entire exposure wavelength range, which may make it difficult to control the resist film thickness.

The transmittance distribution was obtained by dividing the difference between the maximum transmittance (T _max ) and the minimum transmittance (T _min ) at 300 nm to 450 nm by the value obtained by doubling the average transmittance (T _av ) at 300 nm to 450 nm. It is a value obtained by multiplying the value by 100. (Transmissivity distribution = (T _max −T _min ) / (2T _av ) × 100)
As a method for measuring the transmittance, a method of measuring the transmittance of the semitransparent film using the transmittance of the transparent substrate used for the gradation mask as a reference (100%) can be employed. As the apparatus, an ultraviolet / visible spectrophotometer (for example, Hitachi U-4000) or an apparatus having a photodiode array as a detector (for example, Otsuka Electronics MCPD) can be used. The maximum transmittance and the minimum transmittance are the maximum value and the minimum value among the transmittances at 300 nm to 450 nm, and the average transmittance is a value obtained by averaging the transmittances at 300 nm to 450 nm.

  Here, a mercury lamp that is generally widely used as an exposure apparatus is a mercury lamp, and in the emission spectrum of the mercury lamp, a main peak exists in a range of approximately 300 nm to 450 nm. The transmittance distribution within the range is preferably within a predetermined range.

Moreover, it is preferable that the transmittance | permeability distribution in wavelength 250nm -600nm of a semi-transparent film | membrane is 20% or less, More preferably, it is 10% or less. In general, in the manufacturing process of a display device such as a liquid crystal display device, the exposure wavelength range is often set within the range of 250 nm to 600 nm as the exposure condition for pattern formation, so the transmittance distribution at 250 nm to 600 nm is within the above range. This is because a wide wavelength range can be used effectively, which is advantageous for pattern formation, and the resist film thickness can be easily controlled.
The method for calculating the transmittance distribution is as described above.

Further, the transmissivity of the translucent film at a wavelength of 300 nm varies depending on the film thickness of the translucent film and the application of the gradation mask, but is preferably in the range of 10% to 70%. As described above, for example, when a high-pressure mercury lamp is used in the exposure apparatus, since the end of the emission spectrum is approximately 300 nm, if the transmittance at a wavelength of 300 nm is in the above range, the resist curing reaction has a short wavelength. This is because the light in the region can be used more reliably.
In particular, in the case where spacers having different heights are formed using the gradation mask of the present invention, for example, when the difference in height of each pattern is 3 μm or more, the transmittance at 300 nm is 10% to 30%. % Is preferably in the range of 10% to 20%. Further, when the difference in height of each pattern is 3 μm or less, the transmittance at 300 nm is preferably in the range of 30% to 70%, more preferably in the range of 30% to 50%. is there.
The method for measuring the transmittance is as described above.

  Moreover, it is preferable that the average transmittance | permeability in wavelength 250nm -600nm of a translucent film | membrane is in the range of 10%-60%. If the average transmittance is less than the above range, in the pattern formation using the gradation mask of the present invention, the difference in transmittance between the semi-transparent region and the light shielding region may be difficult to occur, and the average transmittance is within the above range. This is because if it exceeds, it may be difficult to produce a difference in transmittance between the translucent region and the transmissive region.

  The translucent film may be a single layer or may be composed of a plurality of layers. When the translucent film is composed of a plurality of layers, it is preferable that at least one layer has the above-described transmittance characteristics. Further, the other layer may have the above-described transmittance characteristics, or may have a transmittance characteristic different from the above-described transmittance characteristics. In this case, a multi-tone gradation mask can be obtained.

  The film thickness of the translucent film is preferably a film thickness that satisfies the above-described transmittance characteristics. In the case of a chromium film, the film thickness can be about 5 nm to 20 nm. Since the transmissivity of the translucent film varies depending on the film thickness, the desired transmissivity can be obtained by controlling the film thickness. Further, when the translucent film contains oxygen, nitrogen, or the like, the transmittance varies depending on the composition, so that the desired transmittance can be realized by simultaneously controlling the film thickness and the composition.

  As a method for forming the translucent film, for example, a physical vapor deposition method (PVD) such as a sputtering method, an ion plating method, or a vacuum vapor deposition method is used.

2. Light-shielding film The light-shielding film used in the present invention substantially does not transmit exposure light, and preferably has an average transmittance of 0.1% or less at the exposure wavelength. As such a light shielding film, a light shielding film generally used for a photomask can be used. For example, a metal film such as chromium, molybdenum silicide, tantalum, aluminum, silicon, or chromium oxide, chromium nitride, chromium oxynitride And films of oxides and nitrides of metals such as silicon oxide and silicon oxynitride. Among them, as the light shielding film, a chromium-based film such as chromium, chromium oxide, chromium nitride, chromium oxynitride is preferably used, and a chromium film is particularly preferable. This is because the chromium-based film has the most proven track record and is preferable in terms of cost and quality. The chromium-based film may be a single layer or may be a laminate of two or more layers.

  Further, the light shielding film may have a low reflection function. Since the low reflection function can prevent irregular reflection of exposure light, a clearer pattern can be formed. In order to add a low reflection function to the light shielding film, for example, a chromium compound such as chromium oxide for preventing reflection of exposure light may be contained on the surface of the light shielding film. In this case, the light shielding film may be formed by an inclined interface in which the content component gradually changes toward the surface.

  The thickness of the light shielding film is not particularly limited, and for example, in the case of a chromium film, it can be about 50 nm to 150 nm.

  As a method for forming the light shielding film, for example, a physical vapor deposition method (PVD) such as a sputtering method, an ion plating method, or a vacuum vapor deposition method is used.

3. Transparent substrate The substrate generally used for a photomask can be used for the transparent substrate used for this invention. For example, optically polished low expansion glass such as borosilicate glass and aluminoborosilicate glass, quartz glass, synthetic quartz glass, Pyrex (registered trademark) glass, soda lime glass, white sapphire and other non-flexible transparent rigid materials Alternatively, a flexible transparent material having flexibility such as a transparent resin film and an optical resin film can be used. Among them, quartz glass is a material having a small coefficient of thermal expansion, and is excellent in dimensional stability and characteristics in high-temperature heat treatment.

4). Light-shielding region, translucent region, and transmissive region The light-shielding region in the present invention is a region where a light-shielding film is provided on a transparent substrate. In the light shielding region, it is sufficient that at least the light shielding film is formed on the transparent substrate, and the light shielding film and the semitransparent film may be formed on the transparent substrate.

  Moreover, the semi-transparent area | region in this invention is an area | region where only the semi-transparent film | membrane was provided on the transparent substrate. In the semi-transparent region, only the semi-transparent film is formed on the transparent substrate, and no light shielding film is formed. When the semi-transparent film is composed of a plurality of layers, the gradation mask may have a plurality of types of semi-transparent regions having different transmittance characteristics. In this case, a multi-tone mask can be obtained.

  Furthermore, the transmission region in the present invention is a region where neither a light-shielding film nor a translucent film is provided on the transparent substrate. That is, the transmissive region has only a transparent substrate.

  The shapes of the light-shielding region, translucent region, and transmissive region are not particularly limited, and are appropriately adjusted according to the use of the gradation mask of the present invention. For example, as shown in FIG. 4, the gradation mask 1 has a linear translucent region 12 having a bent portion and a circular transmissive region 13, and the other region is a light shielding region 11, or FIG. As shown in FIG. 5, the gradation mask 1 has an L-shaped light-shielding region 11 and a circular transmission region 13, and the other region is a semi-transparent region 12. The shape of the transmission region can be various shapes.

  In the gradation mask of the present invention, a transparent substrate, a light shielding film, and a semi-transparent film are laminated in any order. As a layer structure of the gradation mask illustrated in FIG. 4, for example, as shown in FIG. 6A, the transparent substrate 2, the light shielding film 4, and the semi-transparent film 3 may be laminated in this order. As shown in FIG. 6, the transparent substrate 2, the semitransparent film 3, and the light shielding film 4 may be laminated in this order, and as shown in FIG. 6C, the semitransparent film 3, the transparent substrate 2, and the light shielding film 4 are laminated in this order. It may be. 6A to 6C are cross-sectional views taken along line AA in FIG. In this case, the light shielding region 11 is provided with the light shielding film 4 and the semitransparent film 3 on the transparent substrate 2, the semitransparent region 12 is provided with the semitransparent film 3 on the transparent substrate 2, and the transmission region 13 is the transparent substrate. Has only two. When a pattern is formed using such a gradation mask, for example, as shown in FIG. 7, spacers 18a and alignment control protrusions 18b having different heights and shapes can be formed simultaneously.

  5 may be laminated in the order of the transparent substrate 2, the light shielding film 4, and the semi-transparent film 3, as shown in FIG. 8A, for example. As shown in b), the transparent substrate 2, the semitransparent film 3, and the light shielding film 4 may be laminated in this order, and as shown in FIG. 8C, the semitransparent film 3, the transparent substrate 2, and the light shielding film 4 are arranged in this order. It may be laminated. 8A to 8C are cross-sectional views taken along line BB in FIG. In this case, the light shielding region 11 is provided with the light shielding film 4 and the semitransparent film 3 on the transparent substrate 2, the semitransparent region 12 is provided with the semitransparent film 3 on the transparent substrate 2, and the transmission region 13 is the transparent substrate. Has only two. When a pattern is formed using such a gradation mask, for example, as shown in FIG. 9, a spacer 19a and an overcoat layer 19b can be formed simultaneously.

  The semitransparent film and the light shielding film in the present invention are formed in a pattern on the transparent substrate according to the shapes of the light shielding region, the semitransparent region, and the transmission region.

5. Low reflective layer In the present invention, a low reflective layer may be formed on the light shielding film. By providing the low reflection layer, halation can be prevented when the gradation mask of the present invention is used.
Examples of the low reflection layer include films of chromium oxide, chromium nitride, chromium oxynitride, and the like. When the light shielding film is a chromium-based film, these films can be etched simultaneously with the etching of the light shielding film.
For example, as shown in FIG. 6A, when the transparent substrate 2, the light shielding film 4, and the semitransparent film 3 are laminated in this order, the low reflection layer is formed between the light shielding film and the semitransparent film. 6B, when the transparent substrate 2, the semi-transparent film 3, and the light-shielding film 4 are laminated in this order, and as shown in FIG. 6C, the semi-transparent film 3, the transparent substrate 2, When the light shielding films 4 are stacked in this order, the low reflection layer is formed on the light shielding film.

6). Gradation mask The gradation mask of the present invention is one in which the transmittance changes in three steps or more, and is not limited to a two-gradation mask. By repeating patterning as described later, A multi-tone mask having two or more tones can be obtained.

The gradation mask of the present invention can be used for manufacturing various products manufactured through an exposure process, such as a lithography method. Among these, the effects of the present invention can be utilized to the maximum when used for manufacturing a display device such as a liquid crystal display device, an organic EL display device, or a plasma display panel, particularly for manufacturing a large display device.
As applications for simultaneously forming two or more patterns by batch exposure using the gradation mask of the present invention, specifically, simultaneous formation of spacers and alignment control protrusions in a liquid crystal display device, and different heights in a liquid crystal display device Simultaneous formation of spacers, simultaneous formation of spacers and overcoat layers in a liquid crystal display device, simultaneous formation of spacers and alignment control protrusions in a color filter for liquid crystal display devices, simultaneous formation of spacers with different heights in a liquid crystal display device color filter, Examples include simultaneous formation of a spacer and an overcoat layer in a color filter of a liquid crystal display device, and formation of resists having different thicknesses when a semiconductor element is manufactured in a display device.

  The size of the gradation mask of the present invention is appropriately adjusted according to the application. For example, when used for manufacturing a display device such as a liquid crystal display device or an organic EL display device, 300 mm × 400 mm to 1, It can be about 600 mm × 1,800 mm.

7). Next, a method for manufacturing a gradation mask according to the present invention will be described. As a method for manufacturing a gradation mask according to the present invention, a light-shielding region, a semi-transparent region, and a transmission region can be arranged at desired positions by forming a translucent film and a light-shielding film in a pattern on a transparent substrate. Although it will not specifically limit if it is a method which can be mentioned, Two preferable aspects can be mentioned. Hereinafter, each aspect will be described.

(1) 1st aspect The 1st aspect of the manufacturing method of the gradation mask of this invention is the mask blank preparation process which prepares the mask blank which formed the light shielding film on the transparent substrate, and a part of light shielding film. A first patterning step of patterning, a semi-transparent film forming step of forming a semi-transparent film on the entire surface of the transparent substrate on which the patterned light-shielding film is formed, and a second patterning step of patterning the light-shielding film and the semi-transparent film It has.

FIG. 10 is a process diagram showing an example of a method of manufacturing a gradation mask according to this aspect.
In order to produce the gradation mask of this embodiment, first, a mask blank 20 having a light shielding film 4a formed on the transparent substrate 2 is prepared (FIG. 10A, mask blank preparation step).
Next, a resist material is applied on the light-shielding film 4a and baked for a predetermined time after the application, thereby forming a first resist film 21a (FIG. 10B). Next, the light shielding film is subjected to pattern exposure. At this time, the semi-transparent region 12 is exposed by removing the first resist film 21a so as to form a boundary where the semi-transparent region 12 and the light-shielding region 11 contact each other and a boundary where the semi-transparent region 12 and the transmissive region 13 contact each other. The light shielding region 11 and the transmission region 13 are exposed with an exposure amount at which the first resist film 21a remains. Subsequently, development is performed to form a first resist pattern 21b (FIG. 10C). Next, the light shielding film 4a exposed from the first resist pattern 21b is etched to form the light shielding film intermediate pattern 4b (FIG. 10D), and the remaining first resist pattern 21b is removed (FIG. 10D). FIG. 10 (e)). In the light-shielding film intermediate pattern 4b, a portion where the same portion as the translucent film is etched in a second patterning step described later remains without being etched. In addition, FIG.10 (b)-(e) is a 1st patterning process.
Next, a semitransparent film 3a is formed on the entire surface of the transparent substrate 2 on which the light shielding film intermediate pattern 4b is formed (FIG. 10F, a semitransparent film forming process).
Next, a resist material is applied onto the translucent film 3a, and baked for a predetermined time after the application, thereby forming a second resist film 22a (FIG. 10G). Subsequently, pattern exposure of the light shielding film and the semitransparent film is performed. At this time, the transmissive region 13 has an exposure amount at which the second resist film 22a is removed so as to form a boundary where the light shielding region 11 and the transmissive region 13 are in contact and a boundary where the semitransparent region 12 and the transmissive region 13 are in contact. The light shielding region 11 and the translucent region 12 are exposed with an exposure amount at which the second resist film 22a remains. Next, the second resist pattern 22b is formed by developing (FIG. 10H). Next, the semitransparent film 3a exposed from the second resist pattern 22b is etched, and subsequently, the portion where the lower light shielding film intermediate pattern 4b is exposed is further etched, whereby the semitransparent film pattern 3b and A light shielding film pattern 4c is formed (FIG. 10I). Next, the remaining second resist pattern 22b is removed (FIG. 10J), and a gradation mask can be obtained. In addition, FIG.10 (g)-(j) is a 2nd patterning process.

  In this aspect, since only a part of the light shielding film is patterned in the first patterning step and the light shielding film and the semitransparent film are patterned in the second patterning step, the semitransparent film as in the second aspect described later. There is no need to selectively etch only the light-shielding film formed thereon. For this reason, it has the advantage that the material used for a light shielding film and a semi-transparent film is not limited. For example, a similar material, specifically, a chromium film can be used for the light-shielding film and the translucent film. Further, since etching selectivity is not required, it is not necessary to use a plurality of etching techniques (a plurality of apparatuses, etchants, etc.), and the mask manufacturing cost can be reduced. Furthermore, when the light shielding film and the semi-transparent film are chromium films, the gradation mask can be manufactured by the same process as the conventional binary mask, and there is an advantage that a complicated process is not required.

Moreover, since the light-shielding film and the semi-transparent film are simultaneously patterned in the second patterning step as described above, the method for manufacturing the gradation mask according to this aspect includes the same material for the light-shielding film and the semi-transparent film. It is suitable when it is a film. Especially, the case where a light shielding film and a semi-transparent film are metal films is more preferable, and the case where both films are chromium films is particularly preferable.
Hereafter, each process in the manufacturing method of the gradation mask of this aspect is demonstrated.

(I) Mask blank preparatory process The mask blank preparatory process in this aspect is a process of preparing the mask blank which formed the light shielding film on the transparent substrate.
A mask blank in which a chromium film is formed as a light shielding film on a transparent substrate is a commonly used mask blank and can be easily obtained.

(Ii) First Patterning Step The first patterning step in this aspect is a step of patterning a part of the light shielding film. The patterning method of the light shielding film is not particularly limited, and a lithography method is usually used. When the lithography method is used, a resist material is applied on the light shielding film of the mask blank and baked to form a first resist film.

  As the material of the first resist film, either a positive resist material (one that dissolves the light-irradiated portion) or a negative resist material (one that solidifies the light-irradiated portion) can be used. The positive resist material is not particularly limited, and examples thereof include a chemically amplified resist using a novolac resin as a base resin. The negative resist material is not particularly limited. For example, a chemically amplified resist based on a crosslinkable resin, specifically, a chemical amplification obtained by adding a crosslinking agent to polyvinylphenol and further adding an acid generator. Type resist and the like.

  In pattern exposure of the light-shielding film, pattern exposure is performed so that the exposure amount differs in each region so as to form a boundary where the semi-transparent region and the light-shielding region are in contact and a boundary where the semi-transparent region and the transmission region are in contact. At this time, the semi-transparent region is exposed with an exposure amount at which the first resist film is removed, and the light shielding region and the transmissive region are exposed with an exposure amount at which the first resist film remains.

For example, FIG. 10C shows an example in which the first resist film is formed using a positive resist material. In this case, the semi-transparent region 12 is exposed with an exposure amount at which the first resist film 21a is exposed. However, the first resist film 21 a is not exposed in the light shielding region 11 and the transmissive region 13.
Although not shown, when a negative resist material is used for the first resist film, the semi-transparent region is not exposed, and the first resist film is exposed with an exposure amount that exposes the first resist film in the light shielding region and the transmission region.
Note that pattern exposure for collectively etching the same portion of the light shielding film and the semitransparent film is performed in the second patterning step.

  As a method of performing exposure with different exposure amounts depending on each region, there are a method of controlling the exposure amount of energy rays, a method of performing exposure with a constant exposure amount, and the like. The drawing method is not particularly limited, and an electron beam drawing method or a laser drawing method used for normal photomask drawing can be used. When the electron beam drawing method is used, the exposure amount can be easily converted. When the laser drawing method is used, since it takes time to convert the exposure amount, the exposure may be repeated without changing the exposure amount. In addition, with the increase in the size of display devices such as liquid crystal display devices and organic EL display devices, and the increase in the number of facets at the time of manufacture, the tone masks are also increasing in size. Laser drawing method is applied.

  Development after pattern exposure can be performed according to a general development method.

As a method for etching the light shielding film, for example, wet etching using a ceric ammonium nitrate aqueous solution or the like, or dry etching using a chlorine-based gas or the like can be applied. Among these, wet etching is preferable. Wet etching is advantageous in terms of cost and production efficiency. In addition, since the wet etching is dissolved by a chemical reaction, it is preferable from the viewpoint that the etching rate can be easily controlled by selecting an etchant.
When the light shielding film is a chromium film, a cerium nitrate wet etchant is preferably used.
Further, when the light shielding film has a low reflection function, it is possible to prevent exposure of a region that is not originally exposed due to scattering of exposure light for exposing the first resist film.

  The method for removing the first resist film is not particularly limited, and is usually performed by ashing by oxygen plasma treatment or cleaning with an organic alkaline solution.

  In this aspect, after the first patterning step, an inspection step for inspecting the light-shielding film pattern and a correction step for correcting defects as necessary may be performed. When the light shielding film is a chromium film, a general photomask inspection technique and correction technique can be applied. By performing the inspection process of the dimension of the light-shielding film pattern, the defect inspection of the light-shielding film pattern, and the correction process, it is possible to prevent a substrate having a defect from passing over to the next process, increase the yield of non-defective products, and contribute to reducing the mask cost. .

(Iii) Translucent film forming step The translucent film forming step in this embodiment is a step of forming a translucent film on the entire surface of the transparent substrate on which the patterned light-shielding film is formed. The method for forming the translucent film is the same as described above, and thus the description thereof is omitted here.

(Iv) Second Patterning Step The second patterning step in this aspect is a step of patterning the light shielding film and the semitransparent film. The patterning method of the light shielding film and the semitransparent film is not particularly limited, and a lithography method is usually used. When the lithography method is used, a resist material is applied on a transparent substrate on which a light shielding film and a semitransparent film are formed, and baking is performed to form a second resist film.
Note that the material of the second resist film is the same as the material of the first resist film described in the section of the first patterning step, and a description thereof is omitted here.

  In pattern exposure of the semi-transparent film and the light-shielding film, pattern exposure is performed so that the exposure amount varies depending on each region so as to form a boundary where the light-shielding region and the transmissive region are in contact and a boundary where the semi-transparent region and the transmissive region are in contact with each other. . At this time, the transmissive region is exposed with an exposure amount at which the second resist film is removed, and the light shielding region and the semi-transparent region are exposed with an exposure amount at which the second resist film remains.

For example, FIG. 10H shows an example in which the second resist film is formed using a positive resist material. In this case, the second resist film 22a is exposed with an exposure amount at which the second resist film 22a is exposed in the transmission region 13. The second resist film 22a is not exposed in the light shielding region 11 and the translucent region 12.
Although not shown, when a negative resist material is used for the second resist film, exposure is not performed in the transmissive region, but exposure is performed with an exposure amount at which the second resist film is exposed in the light shielding region and the translucent region.

Since the other points of pattern exposure and development are the same as those described in the section of the first patterning step, description thereof is omitted here.
In the present invention, when the translucent film is a chromium film, the film thickness is, for example, about 5 nm to 20 nm and is relatively thin. For this reason, the etching time of a semi-transparent film | membrane can be shortened. Further, since there is almost no difference between the etching rates of the semi-transparent film and the light-shielding film, there is an advantage that the semi-transparent film pattern has no edge fluctuation (the edge is sharp).

  In this step, the same portions of the light shielding film and the semitransparent film are etched together. In the transmissive region, the light shielding film and the semitransparent film are etched together, so that the positions of the end portions of the light shielding film pattern and the end portions of the semitransparent film pattern are substantially the same. The light-shielding film and the translucent film are etched by the same method as the light-shielding film etching method described in the first patterning step, and a description thereof is omitted here.

  The method for removing the second resist film is not particularly limited, and is usually performed by ashing by oxygen plasma treatment or cleaning with an organic alkaline solution.

  In this aspect, after the second patterning step, an inspection step for inspecting the light shielding pattern and the semi-transparent film pattern, and a correction step for correcting defects as necessary may be performed. By performing the inspection process of the light shielding pattern and semi-transparent film pattern dimension inspection, the defect inspection of the light shielding pattern and semi-transparent film pattern, and the correction process, the non-defective product rate is increased and the mask cost is reduced.

(2) 2nd aspect The 2nd aspect of the manufacturing method of the gradation mask of this invention is the mask blank preparation process which prepares the mask blank by which the semi-transparent film and the light shielding film were laminated | stacked in this order on the transparent substrate, This includes a first patterning step for patterning a part of the semitransparent film and the light shielding film, and a second patterning step for patterning only the light shielding film.

FIG. 11 is a process diagram showing an example of a method for manufacturing a gradation mask according to this aspect.
In order to produce the gradation mask of this embodiment, first, a mask blank 20 in which the semitransparent film 3a and the light shielding film 4a are laminated in this order on the transparent substrate 2 is prepared (FIG. 11A, mask blank preparation step). .
Next, a resist material is applied on the light-shielding film 4a and baked for a predetermined time after the application, thereby forming a first resist film 23a (FIG. 11B). Next, pattern exposure of the semitransparent film and the light shielding film is performed. At this time, the transmissive region 13 has an exposure amount at which the first resist film 23a is removed so as to form a boundary where the light shielding region 11 and the transmissive region 13 are in contact and a boundary where the semi-transparent region 12 and the transmissive region 13 are in contact. The light shielding region 11 and the translucent region 12 are exposed with an exposure amount at which the first resist film 23a remains. Subsequently, development is performed to form a first resist pattern 23b (FIG. 11C). Next, the transparent film 3a and the light-shielding film 4a exposed from the first resist pattern 23b are etched to form a semi-transparent film pattern 3b and a light-shielding film intermediate pattern 4b (FIG. 11 (d)). The first resist pattern 23b is removed (FIG. 11E). In the light shielding film intermediate pattern 4b, a portion where only the light shielding film is etched in a second patterning step described later remains without being etched. In addition, FIG.11 (b)-(e) is a 1st patterning process.
Next, a resist material is applied on the transparent substrate 2 on which the semitransparent film pattern 3b and the light-shielding film intermediate pattern 4b are formed, and baked for a predetermined time after the application, thereby forming a second resist film 24a (FIG. 11F). ). Subsequently, pattern exposure of the light shielding film is performed. At this time, the translucent region 12 is exposed by removing the second resist film 24a so as to form a boundary where the translucent region 12 and the light shielding region 11 are in contact and a boundary where the translucent region 12 and the transmissive region 13 are in contact. The light shielding region 11 and the transmission region 13 are exposed with an exposure amount at which the second resist film 24a remains. Next, a second resist pattern 24b is formed by developing (FIG. 11G). Next, the light shielding film intermediate pattern 4b exposed from the second resist pattern 24b is etched to form a light shielding film pattern 4c (FIG. 11H), and the remaining second resist pattern 24b is removed. (FIG. 11 (i)). In addition, FIG.11 (f)-(i) is a 2nd patterning process. In this way, a gradation mask can be obtained.

  In this aspect, as in the first aspect, specifically, a half-transparent film forming step is performed between the first patterning step and the second patterning step. Thus, it is not necessary to perform a semitransparent film forming step. For this reason, the risk (defect, dirt, etc.) at the time of film-forming of a semi-transparent film | membrane can be reduced. Further, TAT (Turn Around Time) can be shortened.

In addition, since the method for manufacturing the gradation mask according to this aspect performs patterning of the light shielding film and the semitransparent film in the first patterning process as described above, the light shielding film and the semitransparent film are formed similarly to the first aspect. It is suitable when the transparent film is a film made of a similar material. In particular, since etching selectivity is required in the second patterning step, it is more preferable that the light shielding film and the translucent film are films having greatly different compositions.
Hereafter, each process in the manufacturing method of the gradation mask of this aspect is demonstrated.

(I) Mask Blank Preparation Step The mask blank preparation step in this aspect is a step of preparing a mask blank in which a semitransparent film and a light shielding film are laminated in this order on a transparent substrate. Note that the transparent substrate, the translucent film, and the light shielding film are as described above, and thus description thereof is omitted here.

(Ii) First Patterning Step The first patterning step in this aspect is a step of patterning a part of the translucent film and the light shielding film. The patterning method of the semitransparent film and the light shielding film is not particularly limited, and a lithography method is usually used. When the lithography method is used, a resist material is applied on the light shielding film of the mask blank and baked to form a first resist film.

  In pattern exposure of the semi-transparent film and the light-shielding film, pattern exposure is performed so that the exposure amount varies depending on the region so as to form a boundary where the light-shielding region and the transmissive region are in contact and a boundary where the semi-transparent region and the transmissive region are in contact. At this time, the transmissive region is exposed with an exposure amount at which the first resist film is removed, and the light shielding region and the semi-transparent region are exposed with an exposure amount at which the first resist film remains.

For example, FIG. 11C shows an example in which the first resist film is formed using a positive resist material. In this case, the first resist film 23a is exposed with an exposure amount at which the first resist film 23a is exposed in the transmission region 13. The first resist film 23a is not exposed in the light shielding region 11 and the translucent region 12.
Although not shown, when a negative resist material is used for the first resist film, exposure is not performed in the transmissive region, but exposure is performed with the exposure amount at which the first resist film is exposed in the light shielding region and the semitransparent region.
Note that pattern exposure for etching only the light shielding film is performed in the second patterning step.

  The material of the first resist film, the other aspects of the pattern exposure of the semitransparent film and the light shielding film, development, the etching method of the semitransparent film and the light shielding film, the method of removing the first resist film, the semitransparent film pattern and the light shielding film Since the pattern inspection process and the semi-transparent film pattern and light-shielding film pattern correction process are the same as in the first embodiment, description thereof is omitted here.

(Iii) Second Patterning Step The second patterning step in this aspect is a step of patterning only the light shielding film. The patterning method of the light shielding film is not particularly limited, and a lithography method is usually used. When the lithography method is used, a resist material is applied on the patterned translucent film and the light-shielding film and baked to form a second resist film.

  In pattern exposure of the light shielding film, pattern exposure is performed so that the exposure amount varies depending on the region so as to form a boundary where the semitransparent region and the light shielding region are in contact and a boundary where the semitransparent region and the transmission region are in contact. At this time, the semitransparent region is exposed with an exposure amount at which the second resist film is removed, and the light shielding region and the transmissive region are exposed with an exposure amount with which the second resist film remains.

For example, FIG. 11G shows an example in which the second resist film is formed using a positive resist material. In this case, the semi-transparent region 12 is exposed with an exposure amount at which the second resist film 24a is exposed. However, the second resist film 24 a is not exposed in the light shielding region 11 and the transmission region 13.
Further, although not shown, when a negative resist material is used for the second resist film, the semi-transparent region is not exposed, and the second resist film is exposed with an exposure amount that exposes the second resist film in the light shielding region and the transmission region.

  Note that the material of the second resist film, the pattern exposure of the light shielding film, and the development are the same as in the first embodiment, and thus description thereof is omitted here.

After the development, the light shielding film is etched. In this embodiment, for example, by utilizing the fact that the etching rate differs depending on the type of chromium-based film, the etching rate of the semi-transparent film is shielded by using a chromium film as the semi-transparent film and a chromium-based film other than the chromium film as the light-shielding film. It can be slower than the etching rate of the film. By making a difference in the etching rate of the semi-transparent film and the light-shielding film, the etching selectivity is improved, and when the upper light-shielding film is etched, the lower semi-transparent film is prevented from being etched together. it can. Thus, by changing the etching rate of the semitransparent film and the light shielding film, the etching selectivity can be improved and the gradation can be made clearer.
Further, by using different kinds of metal films for the semitransparent film and the light shielding film, the etching rate of the semitransparent film can be made slower than the etching rate of the light shielding film.

  The light-shielding film etching method, the second resist film removing method, the light-shielding film pattern inspection process, and the light-shielding film pattern correction process are the same as those in the first aspect, and the description thereof is omitted here. To do.

B. Next, a gradation mask for manufacturing a display device according to the present invention will be described.
The gradation mask for manufacturing a display device of the present invention is characterized in that the above-described gradation mask is used for manufacturing a display device.

A method for forming a member in a display device using the display device manufacturing gradation mask of the present invention will be described with reference to the drawings.
FIG. 2 shows an example in which spacers 16a and 16b having different heights are simultaneously formed in a liquid crystal display device using the display device manufacturing gradation mask 1 of the present invention. Further, by using the display device manufacturing gradation mask 1 shown in FIGS. 4 and 6, the spacers 18a and the alignment control protrusions 18b having different heights and shapes in the liquid crystal display device are simultaneously formed as illustrated in FIG. can do. Further, by using the display device manufacturing gradation mask 1 shown in FIGS. 5 and 8, the spacer 19a and the overcoat layer 19b in the liquid crystal display device can be simultaneously formed as illustrated in FIG. Thus, by using the display device manufacturing gradation mask of the present invention, it is possible to simultaneously form members having different heights and shapes in the display device.

  FIG. 12 shows an example in which a thin film transistor (TFT) is manufactured using the gradation mask 1 for manufacturing a display device of the present invention. Conventionally, when patterning a two-layered translucent film, two exposure processes such as resist coating, exposure / development / etching, exposure / development / etching, and stripping have been required. On the other hand, when the gradation mask for manufacturing a display device of the present invention is used, in order to pattern the two-layered translucent films 32 and 33 formed on the substrate 31, a resist material as illustrated in FIG. Is applied to form a resist film 34, irradiated with light 30 (FIG. 12A), developed (FIG. 12B), and the two-layer translucent films 32 and 33 are etched (FIG. c)), the resist film 34 is ashed (FIG. 12D), only the upper semi-transparent film 33 is etched (FIG. 12E), and the resist film 34 is peeled off (FIG. 12F). ). Therefore, the manufacturing process of the semiconductor element in the display device can be simplified by using the gradation mask for manufacturing the display device of the present invention.

Further, the gradation mask for manufacturing a display device of the present invention uses the above-described gradation mask, and not only the long wavelength region of exposure light but also the short wavelength region is used for the curing reaction, which is advantageous for pattern formation. It is.
Therefore, by using the display device manufacturing gradation mask of the present invention, the display device manufacturing process can be simplified and the exposure time can be shortened.

The size of the gradation mask for manufacturing a display device of the present invention is usually about 300 mm × 400 mm to 1,600 mm × 1,800 mm.
The other points of the gradation mask for manufacturing the display device are the same as those described in the above section “A. Gradation mask”, and thus description thereof is omitted here.

  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.

Hereinafter, the present invention will be specifically described using examples and comparative examples.
[Example 1]
(Production of gradation mask)
A commercially available photoresist (ip-3500, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is placed on a conventional mask blank in which a chromium film (light-shielding film) is formed to a thickness of 100 nm on an optically polished 390 mm × 610 mm synthetic quartz substrate. After coating with a thickness of 600 nm and baking on a hot plate heated to 120 ° C. for 15 minutes, a desired light-shielding film intermediate pattern was drawn with a photomask laser drawing apparatus (LRS11000-TFT3 manufactured by Micronic Co., Ltd.).
Next, development was performed with a dedicated developer (NMD3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) to obtain a resist pattern for a light shielding film.
Next, the resist pattern was used as an etching mask, the light shielding film was etched, and the remaining resist pattern was stripped to obtain a desired light shielding film intermediate pattern. A commercially available cerium nitrate wet etchant (MR-ES manufactured by The Inktec Co., Ltd.) was used for etching the light shielding film. The etching time of the light shielding film was 60 seconds.

Next, the substrate on which the light-shielding film intermediate pattern is formed is subjected to pattern dimension inspection, pattern defect inspection, pattern correction as necessary, and after being washed well, the chromium film (translucent film) is sputtered under the following conditions. To form a film.
<Film formation conditions>
・ Gas flow ratio Ar: N ₂ = 4: 1
・ Power: 1.3kW
・ Gas pressure: 3.5mTorr
The film thickness of the semitransparent film was 10 nm. A spectral spectrum of the semitransparent film is shown in FIG.
Next, a commercially available photoresist (ip-3500 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was again applied on the semitransparent film at a thickness of 600 nm and baked on a hot plate heated to 120 ° C. for 15 minutes.
Subsequently, an image to be a translucent film pattern was drawn again with a laser drawing device (LRS11000-TFT3 manufactured by Micronic Co., Ltd.) and developed with a dedicated developer (NMD3 manufactured by Tokyo Ohka Kogyo Co., Ltd.) to obtain a resist pattern.
Next, using the resist pattern as a mask, the semitransparent film and the light shielding film were etched with a commercially available cerium nitrate wet etchant (MR-ES manufactured by The Inktec Co., Ltd.) to obtain a semitransparent film pattern and a light shielding film pattern. Etching was performed on the translucent film and the light shielding film.
Finally, the remaining resist was peeled off, and after undergoing inspection processes such as pattern dimension inspection and pattern defect inspection, pattern correction was performed as necessary to obtain a gradation mask.

(Pattern formation using gradation mask)
A glass substrate having a size of 100 mm × 100 mm and a thickness of 0.7 mm was prepared. A negative photosensitive resin composition (Optomer NN850 manufactured by JSR) was applied onto the glass substrate by spin coating, and dried under reduced pressure. Pre-baked at 3 ° C. for 3 minutes. Then, it exposed on the following conditions through said gradation mask.
<Exposure conditions>
・ Exposure amount: 100 mJ / cm ² (I-line conversion)
・ Exposure gap: 150μm

  Next, development was performed using an aqueous potassium hydroxide solution, and then heat treatment was performed at 230 ° C. for 30 minutes to form two types of convex patterns.

[Comparative Example 1]
(Production of gradation mask)
A gradation mask was produced in the same manner as in Example 1 except that a semitransparent film was formed as described below.
The substrate on which the light-shielding film intermediate pattern is formed is subjected to pattern dimension inspection, pattern defect inspection, pattern correction as necessary, and after cleaning, a chromium oxynitride carbide film (translucent film) is formed by sputtering. did. The thickness of the chromium oxynitride chromium carbide film was 35 nm. The spectrum of this chromium oxynitride chromium carbide film is shown in FIG.

(Pattern formation using gradation mask)
In the same manner as in Example 1, two types of convex patterns were formed.

[Comparative Example 2]
(Production of gradation mask)
A gradation mask was produced in the same manner as in Example 1 except that a semitransparent film was formed as described below.
The substrate on which the light-shielding film intermediate pattern is formed is subjected to pattern dimension inspection, pattern defect inspection, pattern correction as necessary, and after being washed well, a high refractive index layer (refractive index: 2.5, thickness: 29 nm, TiO 2 ₂ layers) and low refractive index layers (refractive index: 1.5, thickness: 48 nm SiO ₂ film) alternately for a total of 15 layers (the first and 15th layers are high refractive index layers), by sputtering A film was formed. Thereby, the translucent film | membrane which cuts the short wavelength range below wavelength 330nm was obtained.

(Pattern formation using gradation mask)
In the same manner as in Example 1, two types of convex patterns were formed.

[Evaluation]
The cross-sectional shape of the pattern formed using the gradation masks of Example 1 and Comparative Examples 1 and 2 was observed with a scanning electron microscope, and the dimensions were measured.

  By using the gradation mask of Example 1 for the exposure process, cell holding column spacers having different heights could be formed with desired dimensions.

DESCRIPTION OF SYMBOLS 1 ... Tone mask 2 ... Transparent substrate 3 ... Semi-transparent film 4 ... Light-shielding film 11 ... Light-shielding area 12 ... Semi-transparent area 13 ... Transmission area

Claims (2)

A transparent substrate, a light shielding film, and a translucent film having a transmittance adjusting function are stacked in random order, a light shielding region in which the light shielding film is provided on the transparent substrate, and only the semitransparent film on the transparent substrate And a transmissive region in which neither the light-shielding film nor the semi-transparent film is provided on the transparent substrate, and a gradation mask for manufacturing a display device used for manufacturing a display device Because
The translucent film is a metal film;
The gray scale mask for manufacturing a display device does not have an etching stopper film.   The gradation mask for manufacturing a display device according to claim 1, wherein the translucent film and the light shielding film are chromium films.

Images