JP5239591B2 - Gradation mask and manufacturing method thereof - Google Patents

Description

  The present invention relates to a gradation mask suitably used for halftone exposure in a manufacturing process or the like of a color filter used in a liquid crystal display device, and a manufacturing method thereof.

  In recent years, with the development of personal computers, especially portable personal computers, the demand for liquid crystal displays, particularly color liquid crystal displays, has been increasing.

  For the purpose of improving the production efficiency of the color filter used in such a liquid crystal display device, for example, a method of forming an overcoat layer and a spacer at once using a gradation mask, an alignment control protrusion and a spacer And a method of collectively forming a colored layer for a reflective portion formed on a reflective portion of a color filter for a transflective liquid crystal display device and a colored layer for a transmissive portion formed on a transmissive portion Etc. have been proposed (see, for example, Patent Documents 1 to 5).

  As an example of the gradation mask, for example, as shown in FIG. 12, a transparent substrate 102, a semi-transparent film 103 formed on the transparent substrate 102 and transmitting exposure light with a desired transmittance, and the semi-transparent film And a light-shielding film 104 that substantially shields the exposure light formed on 103. Such a gradation mask includes a transparent region 113 through which the transparent substrate 102 is exposed and transmitting light, a light-blocking region 111 that does not substantially transmit light through the light-blocking film 104, and the amount of light transmitted through the semi-transparent film 103. And a semi-transparent region 112 adjusted, and gradation can be obtained by the difference in transmittance.

JP 2007-171623 A JP 2007-171624 A JP 2007-178649 A JP 2007-178662 A JP 2007-178688 A

  However, in the case where a semi-transparent region and a transmission region are adjacent to each other, such as when forming various members of a color filter using such a gradation mask, interference occurs due to a phase shift of light passing through each region. Waves are likely to occur. For this reason, it may be difficult to form various members in a target pattern in a region corresponding to the translucent region.

  For example, as shown in FIG. 4, when the negative photosensitive resin is exposed using the gradation mask and the overcoat layer 51 and the spacer 52 are collectively formed, interference occurs due to the influence of the light phase shift. In some cases, the film thickness of the overcoat layer 51 becomes thick in the vicinity of the boundary with the spacer 52, resulting in a defective exposure pattern. For this reason, when the color filter and the liquid crystal drive side substrate are opposed to each other to form a liquid crystal display device, the above-mentioned exposure defect pattern causes a liquid crystal alignment defect, and high-quality display becomes difficult.

  For example, as shown in FIG. 8, when the positive photosensitive resin is exposed using the gradation mask and the alignment control protrusion 53 and the spacer 54 are formed in a lump, due to the influence of the light phase shift. Interference occurs, and the film thickness of the alignment control projection 53 becomes a thin film near the boundary between the translucent region and the transmissive region, and an exposure failure pattern may occur. For this reason, when the color filter and the liquid crystal drive side substrate are opposed to each other to form a liquid crystal display device, the above-mentioned exposure defect pattern causes a liquid crystal alignment defect, and high-quality display becomes difficult.

  Further, for example, when the reflective portion colored layer formed on the reflective portion of the color filter for a transflective liquid crystal display device and the transmissive portion colored layer formed on the transmissive portion are formed in a lump, a half of the gradation mask is formed. The thickness of the colored layer for the reflective part formed using the transparent part may become a thick film or a thin film near the boundary between the translucent region and the transmissive region, resulting in a poor exposure pattern. For this reason, the optical path length on the reflecting portion side is not uniform, the transmittance is not uniform, or the color of the colored layer is changed.

  The present invention has been made in view of the above problems, and provides a gradation mask in which a semi-transparent region and a transmission region are adjacent to each other, and an exposure failure pattern due to light interference hardly occurs, and a method for manufacturing the same. The main purpose.

  In order to achieve the above object, the present invention has a transparent substrate and a translucent film formed in a pattern on the transparent substrate, and the transparent region is exposed on the transparent region and the transparent substrate. A gradation mask having a semi-transparent region provided with a semi-transparent film, and having a pattern in which the transmissive region and the semi-transparent region are adjacent to each other, and a light intensity distribution at the time of exposure using the gradation mask When the simulation is performed, the light intensity monotonously decreases from the transmissive area toward the semi-transparent area at a distance within 5 μm from the boundary between the transmissive area and the semi-transparent area, and changes to a light intensity distribution. Provided is a gradation mask characterized by having no inflection point.

  According to the present invention, when the gradation mask performs the above simulation, the light intensity is monotonously from the transmission region to the semitransparent region in a region at a predetermined distance from the boundary between the transmission region and the semitransparent region. Since the light intensity distribution does not have an inflection point, the influence of the interference of diffracted light can be reduced in a region where the transmission region and the semitransparent region are adjacent to each other. Therefore, by using the gradation mask of the present invention, it is possible to pattern a photosensitive resin in a desired pattern, and it is possible to form various members with high definition.

  In the gradation mask of the present invention, the transmittance of the semitransparent region at a wavelength of 365 nm is T (%), and the phase delay of the exposure light that has passed through the semitransparent region with respect to the exposure light that has passed through the transmissive region is δ. In the case of (rad), -δ / ln (T / 100) is preferably 0.4 or less. Since −δ / ln (T / 100) is in the above range, as described above, in the region where the transmissive region and the semitransparent region are adjacent to each other, the influence of light interference can be reduced. It is.

  Furthermore, in the present invention, it is preferable that the translucent film contains at least one metal selected from the group consisting of chromium, titanium, nickel, nickel alloy and tantalum. This is because with such a semi-transparent film, the phase delay of the exposure light that has passed through the semi-transparent region relative to the exposure light that has passed through the transmission region can be made relatively small.

  In the gradation mask of the present invention, the light shielding film may be formed in a pattern on the transparent substrate, and the gradation mask may have a light shielding region in which the light shielding film is provided on the transparent substrate. . In this case, the translucent region is a region where only the translucent film is provided on the transparent substrate.

  Furthermore, the present invention has a transparent substrate and a translucent film formed in a pattern on the transparent substrate, and the translucent film is provided on the transparent region where the transparent substrate is exposed and the transparent substrate. A method of manufacturing a gradation mask having a semi-transparent region, and having a pattern in which the transmissive region and the semi-transparent region are adjacent to each other, using the gradation mask as a material for forming the semi-transparent film When a simulation of the light intensity distribution at the time of exposure is performed, the light intensity monotonously from the transmissive area toward the semi-transparent area in a region within 5 μm from the boundary between the transmissive region and the semi-transparent region. A gradation having a translucent film forming step of selecting a material that decreases and has no inflection point in the light intensity distribution, and forming the translucent film using the material Proposed mask manufacturing method To.

  According to the present invention, when the above simulation is performed as a material for forming the translucent film, the translucent region is directed to the translucent region at a predetermined distance from the boundary between the translucent region and the translucent region. Therefore, the material is selected so that the light intensity decreases monotonously and the light intensity distribution does not have an inflection point. A small number of gradation masks can be obtained. That is, it is possible to pattern a photosensitive resin in a target pattern, and to obtain a gradation mask capable of forming various members with high definition.

  In the above invention, the material has a transmittance of T (%) at a wavelength of 365 nm in the semi-transparent region, and the phase delay of the exposure light that has passed through the semi-transparent region with respect to the exposure light that has passed through the transmissive region is δ. In the case of (rad), a material having −δ / ln (T / 100) of 0.4 or less is preferable. By selecting a material with −δ / ln (T / 100) of 0.4 or less as a material for forming the translucent film, the transmissive region and the translucent region are adjacent to each other as described above. This is because a gradation mask that is less affected by light interference can be obtained in the region.

  In the present invention, it is possible to reduce the influence of interference waves due to the phase shift of light that has passed through each region, and it is possible to pattern a photosensitive resin in a desired pattern shape. Play.

  Hereinafter, the gradation mask of the present invention and the manufacturing method thereof will be described in detail.

A. Tone Mask First, the tone mask of the present invention will be described.
The gradation mask of the present invention has a transparent substrate and a translucent film formed in a pattern on the transparent substrate, and the translucent film is exposed on the transparent region where the transparent substrate is exposed and on the transparent substrate. A gradation mask having a semi-transparent area provided and having a pattern in which the transmissive area and the semi-transparent area are adjacent to each other, and a light intensity distribution during exposure using the gradation mask was simulated. In some cases, the light intensity monotonously decreases from the transmissive region to the semi-transparent region at a distance within 5 μm from the boundary between the transmissive region and the semi-transparent region, and the light intensity distribution has an inflection point. It is a characteristic that it is not.

The gradation mask of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an example of the gradation mask of the present invention. FIG. 1 (a) is a cross-sectional view taken along the line AA of FIG. 1 (b). As illustrated in FIG. 1A, the gradation mask 1 is obtained by forming a translucent film 3 and a light shielding film 4 in a pattern on a transparent substrate 2. Further, as illustrated in FIG. 1B, the gradation mask 1 is provided with a light shielding region 11 in which a light shielding film 4 is provided on a transparent substrate 2 and only a semitransparent film 3 on the transparent substrate 2. It has a semi-transparent region 12 and a transmissive region 13 where the transparent substrate 2 is exposed, and the semi-transparent region 12 and the transmissive region 13 have an adjacent pattern.
The gradation mask is a region at a predetermined distance from the boundary between the transmissive region and the semi-transparent region when the light intensity distribution at the time of exposure using the gradation mask is simulated. The light intensity decreases monotonously toward the point, and the light intensity distribution has no inflection point.

In the simulation, the light amplitude E _P at the point P on the substrate is calculated from each point of the opening (transmission region) of the corresponding gradation mask by the following formula (1) based on general Fresnel diffraction. The integral value of the spherical wave is obtained by calculation, and the light intensity I at the point P can be obtained by calculation according to the following mathematical formula (2).
FIG. 2 is a diagram for explaining the calculation of the light intensity distribution at the point P on the substrate 31 by the following formula (1), and an arbitrary point Q in the opening (transmission region 13) of the gradation mask 1. FIG. 6 is a schematic diagram showing a positional relationship with an arbitrary point P on the substrate 31. In FIG. 2, a point S is a position on the substrate 31 when the exposure light 32 that has passed the point Q travels straight.

Here, in Equation (1), k = 2π / λ, E _P is the amplitude of light at point P on the substrate, A is a constant determined by the intensity of incident light, λ is the wavelength of incident light, and δ is a line The angle formed by the minute QS and the line QP, r is the distance from the point Q to the point P, and i is an imaginary unit.

I = E _P × E _P ^* (2)
Here, in Equation (2), E _P ^* is a conjugate complex number of E _P.

  The above calculation is performed by a computer by dividing the opening (transmission region) of the gradation mask and the substrate into finite minute sections.

  FIG. 3 shows the result of the light intensity distribution obtained by simulation using the gradation mask shown in FIG. Note that FIG. 3 corresponds to the BB line portion of FIG. Simulation conditions are: exposure gap: 150 μm, Collimation: 1.5 °, exposure wavelength: 365 nm, transmissivity of translucent area: 10% (365 nm), exposure light passing through translucent area relative to exposure light passing through transmissive area Phase delay (phase difference): 0.03 rad or 2.34 rad, transmissive region diameter: 15 μmφ, exposure method: proximity exposure method.

  In the case of FIG. 3 (a), the light intensity monotonously decreases from the transmissive area to the semi-transparent area at a predetermined distance from the boundary between the transmissive area and the semi-transparent area, and the inflection point in the light intensity distribution. Does not have On the other hand, in the case of FIG. 3B, there is a portion where the light intensity increases without decreasing monotonously from the transmissive region to the semi-transparent region in a region at a predetermined distance from the boundary between the transmissive region and the semi-transparent region.

When exposure is performed using a gradation mask showing the light intensity distribution as shown in FIG. 3B, the film thickness of the area corresponding to the translucent area becomes thick near the boundary with the transmission area due to light interference. Cheap.
FIG. 4 shows an example in which an overcoat layer and a spacer are formed using a gradation mask having a light intensity distribution as shown in FIG. When the negative photosensitive resin is irradiated with light 50 through the gradation mask, interference occurs due to the effect of light phase shift or the like, and the film thickness of the overcoat layer 51 becomes thick near the boundary with the spacer 52. As a result, a defective exposure pattern is generated. Thus, it can be said that the pattern actually obtained and the simulation result are in agreement.

On the other hand, when exposure is performed using a gradation mask having a light intensity distribution as shown in FIG. 3A, the occurrence of an exposure failure pattern due to light interference can be suppressed.
FIG. 5 shows an example in which an overcoat layer and a spacer are formed using a gradation mask having a light intensity distribution as shown in FIG. When the negative photosensitive resin is irradiated with light 50 through a gradation mask, an exposure failure pattern due to light interference does not occur, and the overcoat layer 51 and the spacer 52 can be formed in a desired pattern. Also in this case, it can be said that the actually obtained pattern and the simulation result coincide.

In the above example, a negative photosensitive resin is used, but a case where a positive photosensitive resin is used will also be described.
FIG. 6 is a schematic view showing another example of the gradation mask of the present invention, and FIG. 6A is a cross-sectional view taken along the line CC of FIG. 6B. As illustrated in FIG. 6A, the gradation mask 1 is obtained by forming a translucent film 3 and a light shielding film 4 in a pattern on a transparent substrate 2. In addition, as illustrated in FIG. 6B, the gradation mask 1 is provided with the light shielding region 11 in which the light shielding film 4 is provided on the transparent substrate 2 and only the semitransparent film 3 on the transparent substrate 2. It has a semi-transparent region 12 and a transmissive region 13 where the transparent substrate 2 is exposed, and the semi-transparent region 12 and the transmissive region 13 have an adjacent pattern.

  FIG. 7 shows the result of obtaining the light intensity distribution by simulation using the gradation mask shown in FIG. Note that FIG. 7 corresponds to the DD line portion of FIG. Simulation conditions are: exposure gap: 150 μm, Collimation: 1.5 °, exposure wavelength: 365 nm, transmissivity of translucent area: 30% (365 nm), exposure light passing through translucent area relative to exposure light passing through transmissive area Phase delay (phase difference): 0.02 rad or 1.22 rad, line width of translucent region: 15 μm, exposure method: proximity exposure method.

  In the case of FIG. 7 (a), the light intensity decreases monotonously from the transmissive area to the semi-transparent area at a predetermined distance from the boundary between the transmissive area and the semi-transparent area, and the inflection point in the light intensity distribution. Does not have On the other hand, in the case of FIG. 7B, there is a portion where the light intensity increases without decreasing monotonously from the transmissive region to the semi-transparent region in a region at a predetermined distance from the boundary between the transmissive region and the semi-transparent region.

When exposure is performed using a gradation mask showing a light intensity distribution as shown in FIG. 7B, the film thickness of the region corresponding to the translucent region tends to become a thin film near the boundary with the transmission region due to light interference. .
FIG. 8 shows an example in which alignment control protrusions and spacers are formed using a gradation mask having a light intensity distribution as shown in FIG. When the positive photosensitive resin is irradiated with the light 50 through the gradation mask, interference occurs due to the influence of a light phase shift or the like, and the film thickness of the alignment control protrusion 53 is reduced between the translucent region 12 and the transmissive region 13. A thin film is formed in the vicinity of the boundary, resulting in a defective exposure pattern. In this case, it can be said that the actually obtained pattern matches the simulation result.

On the other hand, when exposure is performed using a gradation mask having a light intensity distribution as shown in FIG. 7A, the occurrence of an exposure failure pattern due to light interference can be suppressed.
FIG. 9 shows an example in which alignment control protrusions and spacers are formed using a gradation mask having a light intensity distribution as shown in FIG. When the positive photosensitive resin is exposed using the gradation mask, an exposure failure pattern due to light interference does not occur, and the alignment control protrusion 53 and the spacer 54 can be formed in a desired pattern. Also in this case, it can be said that the actually obtained pattern and the simulation result coincide.

  As described above, when exposure is performed using the gradation mask of the present invention, when the above-described simulation is performed, the gradation mask is a region at a predetermined distance from the boundary between the transmission region and the translucent region. The light intensity decreases monotonously from the transmissive area to the semi-transparent area and has no inflection point in the light intensity distribution. It is possible to improve. Therefore, by using the gradation mask of the present invention, the photosensitive resin can be patterned into a target pattern. Thereby, for example, various members such as a color filter can be formed with high definition.

In the gradation mask of the present invention, when the simulation is performed as described above, the light intensity decreases monotonously from the transmissive region to the semi-transparent region at a predetermined distance from the boundary between the transmissive region and the semi-transparent region. In addition, the light intensity distribution has no inflection point in a region at a predetermined distance from the boundary between the transmission region and the translucent region.
Since the light intensity distribution obtained by the simulation varies depending on the exposure gap, the exposure wavelength, the exposure method, and the like, the simulation conditions may be the same as the exposure conditions when the gradation mask is actually used.

Note that “an area within a distance of 5 μm from the boundary between the transmissive area and the semi-transparent area” means an area within 5 μm from the boundary between the transmissive area and the semi-transparent area, and the transmissive area and the semi-transparent area. An area within 5 μm from the boundary to the transmission area.
In addition, “having no inflection point” means that there is no point that changes from an upward convex state to a concave upward state, or a point that changes from an upward concave state to an upward convex state. Say.
The simulation results show that the light intensity decreases monotonously from the transmissive area to the semitransparent area and has no inflection point in the light intensity distribution in the area at a predetermined distance from the boundary between the transmissive area and the translucent area. Shall be confirmed. At this time, assuming that the relative intensity of the exposure light before passing through the gradation mask, that is, the relative intensity of the exposure light passing through the transmission region is 1, a change within ± 0.001 is regarded as an error.

  Hereinafter, the gradation mask of the present invention will be described in detail for each configuration.

1. Transmission region and translucent region The transmission region in the present invention is a region where the transparent substrate is exposed.
Moreover, the semi-transparent area | region in this invention is an area | region where the translucent film | membrane was provided on the transparent substrate. As will be described later, when the gradation mask has a light shielding region, the semitransparent region is a region in which only the semitransparent film is provided on the transparent substrate.

  Here, the occurrence of an exposure failure pattern due to light interference is caused by a delay in the phase of the exposure light that has passed through the semi-transparent region with respect to the exposure light that has passed through the transmission region. When the phase delay of the exposure light that has passed through the semi-transparent area with respect to the exposure light that has passed through the transmission area is relatively large, an exposure failure pattern due to light interference is likely to occur, and the translucent area for the exposure light that has passed through the transmission area When the phase delay of the exposure light that has passed through is relatively small, it becomes difficult to produce a defective exposure pattern due to light interference.

  Therefore, it is preferable to reduce the phase delay of the exposure light that has passed through the translucent region with respect to the exposure light that has passed through the transmission region to such an extent that no interference wave is generated. This phase difference limit varies depending on the transmissivity of the translucent region. Specifically, when the transmissivity of the translucent region at a wavelength of 365 nm is T (%) and the phase delay of the exposure light that has passed through the translucent region with respect to the exposure light that has passed through the transmissive region is δ (rad). , −δ / ln (T / 100) is desirably small enough not to generate an interference wave. More specifically, −δ / ln (T / 100) is preferably 0.4 or less. This is because by setting −δ / ln (T / 100) in the above range, the influence of interference can be reduced and a desired pattern can be formed. On the other hand, when -δ / ln (T / 100) exceeds the above range, the influence of interference due to light wraparound becomes large, and there is a possibility that a poorly exposed pattern may occur when the photosensitive resin is exposed.

In addition, the phase of the exposure light which passed each said area | region can be measured by brand name MPM-100 (made by Lasertec Corporation). As a result, the phase delay δ of the exposure light that has passed through the translucent region relative to the exposure light that has passed through the transmission region can be obtained.
The transmissivity T at a wavelength of 365 nm in the translucent region can be calculated by measuring the transmissivity of the translucent region with the transmissivity of the transparent substrate of the gradation mask as a reference (100%). As a device for measuring the transmittance, an ultraviolet / visible spectrophotometer (for example, Hitachi U-4000) or a device having a photodiode array as a detector (for example, Otsuka Electronics MCPD) can be used.

  Examples of the method of setting −δ / ln (T / 100) within the above range include a method of controlling the refractive index of the material of the semitransparent film and the film thickness of the semitransparent film, as will be described later.

  The gradation mask of the present invention may have a plurality of types of translucent regions having different transmittance characteristics. In this case, a multi-tone mask can be obtained. For example, as will be described later, a plurality of types of semi-transparent regions having different transmittance characteristics can be provided by forming a plurality of layers of semi-transparent films.

  The shape of the transmissive region and the semi-transparent region is not particularly limited as long as the transmissive region and the semi-transparent region are adjacent patterns, and is appropriately selected according to the application of the gradation mask of the present invention. . For example, various shapes, such as a circle, a rectangle, a polygon, and a line, are mentioned. Among them, a pattern in which the transmissive region 13 illustrated in FIG. 1B is surrounded by the semi-transparent region 12, or a semi-transparent region 12 illustrated in FIG. 6B is surrounded by the transmissive region 13. The shape which becomes the pattern which exists is preferable.

  In the case of a pattern in which the transmissive region is surrounded by a semi-transparent region, it is particularly preferable that the shape of the transmissive region is a circle, a polygon, or the like. In the case of a pattern in which the translucent area is surrounded by the transmissive area, it is particularly preferable that the shape of the translucent area is circular, linear, or the like.

2. Translucent film The translucent film used in the present invention is formed in a pattern on a transparent substrate and has a transmittance adjusting function.

As described above, it is preferable that the phase delay of the exposure light that has passed through the semi-transparent region with respect to the exposure light that has passed through the transmission region is relatively small, and the exposure light that has passed through the semi-transparent region with respect to the exposure light that has passed through the transmission region. It is preferable that the phase delay is not more than a predetermined value.
Examples of the material of the translucent film capable of realizing such a light phase difference include metals such as chromium, titanium, nickel, nickel alloy, molybdenum silicide, tantalum, aluminum, silicon, cobalt, and cobalt alloy. Among these, chromium, titanium, nickel, nickel alloy, and tantalum are preferable from the viewpoint of patternability. That is, it is preferable that the translucent film contains at least one metal selected from the group consisting of chromium, titanium, nickel, nickel alloy and tantalum.

  The semi-transparent region is a region where only a semi-transparent film is provided on the transparent substrate, and the transmissive region is a region where the transparent substrate is exposed. Therefore, when the phase difference of the semitransparent film is relatively small, the phase delay of the exposure light that has passed through the semitransparent region with respect to the exposure light that has passed through the transmission region can be made relatively small.

The phase difference of the translucent film is indicated by the product of the refractive index of the material constituting the translucent film and the film thickness of the translucent film. Therefore, the material constituting the translucent film preferably has a relatively low refractive index.
Examples of such a material having a relatively low refractive index include metals such as chromium, tantalum, and titanium, and compounds containing these metals.

  Here, when a metal is formed as a semitransparent film by a general method, a trace amount of oxygen and nitrogen are usually contained in the film. In order to realize the effect of the present invention, the content of the metal in the translucent film formed using a metal is preferably 97% or more, and more preferably 99% or more. Further, the content of nitrogen in the translucent film formed using a metal is preferably 3% or less, and more preferably 2% or less. Furthermore, the oxygen content in the translucent film formed using a metal is preferably 3% or less, and more preferably 2% or less.

  Further, the transmittance of the translucent film is not particularly limited.

  The translucent film may be a single layer, or may be a film in which a plurality of films made of the above materials are laminated. In addition, when the translucent film | membrane consists of the film | membrane which consists of the material mentioned above in multiple layers, it is preferable that the number of laminated | stacked films | membranes shall be about 2 to 3 layers normally, and it shall be especially 2 layers. This is preferable from the viewpoint of controlling the phase difference.

  Further, since the transmissivity of the semitransparent film varies depending on the film thickness, the film thickness of the translucent film is appropriately selected according to the target transmissivity.

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.
For example, when forming a translucent film using chromium by sputtering, a carrier gas such as Ar gas is introduced into the reaction apparatus, and the translucent film is formed by reactive sputtering using a Cr target. can do. At this time, in addition to the carrier gas such as Ar gas, nitrogen gas or the like may be introduced into the reactor, but the composition of the translucent film is controlled by controlling the ratio of the flow rate of each gas. Therefore, when the flow rate of Ar gas is 1, the flow rate ratio of nitrogen gas is preferably 0.2 or less.

  The translucent film is formed in a pattern on the transparent substrate according to the shape of the translucent region.

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 area and light-shielding film The gradation mask of the present invention may have a light-shielding area in which a light-shielding film is formed in a pattern on a transparent substrate and the light-shielding film is provided on the transparent substrate.

  The light shielding region may be a region where a light shielding film is formed on the transparent substrate, and only the light shielding film may be formed on the transparent substrate, and the light shielding film and the semitransparent film are formed on the transparent substrate. Also good. When the light-shielding film and the semi-transparent film are formed on the transparent substrate, the order of lamination of the transparent substrate, the light-shielding film and the semi-transparent film is not particularly limited, and is transparent as illustrated in FIG. The order may be substrate 2 / semi-transparent film 3 / light-shielding film 4, and may be in the order of transparent substrate 2 / light-shielding film 4 / semi-transparent film 3 as illustrated in FIG. As illustrated in FIG. 10B, the order of the semitransparent film 3, the transparent substrate 2, and the light shielding film 4 may be used.

  The shape of the light-shielding region is not particularly limited as long as the transmissive region and the semi-transparent region are adjacent patterns, and is appropriately selected according to the application of the gradation mask of the present invention. For example, various shapes, such as a circle, a rectangle, a polygon, and a line, are mentioned.

Moreover, the light shielding film used in the present invention is formed in a pattern on a transparent substrate.
The light-shielding film does not substantially 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, titanium, or chromium oxide, chromium nitride, Examples thereof include films of oxides and nitrides of metals such as chromium oxynitride, silicon oxide, and silicon oxynitride. In addition, a nickel alloy, a cobalt alloy, a nickel-cobalt alloy, and films of these oxides, nitrides, oxynitrides, oxynitride carbides, and the like can also be used.

  Among them, examples of the light-shielding film include chromium-based films such as chromium, chromium oxide, chromium nitride, and chromium oxynitride; Ni—Cu—Ti and Ni—Ta—Cu—Ti mainly composed of nickel, and oxides thereof. Nickel alloy films such as nitride, oxynitride, oxynitride carbide, etc .; Co—Cu—Ti and Co—Ta—Cu—Ti mainly composed of cobalt, and oxides, nitrides, oxynitrides thereof, Cobalt alloy films such as oxynitride carbides; Ni—Co—Cu—Ti mainly composed of nickel and cobalt, and nickel-cobalt alloy films such as oxides, nitrides, oxynitrides and oxynitride carbides thereof Preferably used. The chromium 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 is appropriately selected depending on the type of the light shielding film. For example, in the case of a chromium film, the thickness is preferably about 50 nm to 150 nm.

  In addition, 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.

  The light shielding film is formed in a pattern on the transparent substrate according to the shape of the light shielding region.

5. Gradation mask The gradation mask of the present invention is not particularly limited as long as the translucent region and the transmissive region are formed, and the light shielding region may be formed as described above. Furthermore, for example, an alignment region or the like may be formed as necessary.

  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.

  Specifically, the spacer and the alignment control protrusion in the liquid crystal display device or the color filter for the liquid crystal display device are formed simultaneously, the spacer and the overcoat layer in the liquid crystal display device or the color filter for the liquid crystal display device are formed simultaneously, the liquid crystal display device or Simultaneous formation of spacers having different heights in a color filter for a liquid crystal display device, simultaneous formation of a colored layer for a transmissive portion and a colored layer for a reflective portion in a semi-transmissive liquid crystal display device or a color filter for a semi-transmissive liquid crystal display device, semi-transmissive Formation of overcoat layer and gap adjusting layer in color filter for liquid crystal display device or transflective liquid crystal display device, overcoat layer for white pattern in color filter for organic EL display device or organic EL display device, and red, green, Same as overcoat layer for blue pattern Formation, such as the drain electrode and the channel of the simultaneous formation of a thin film transistor (TFT) can be exemplified.

  In particular, when the negative photosensitive resin is exposed using the gradation mask of the present invention, a spacer and an overcoat layer are simultaneously formed in a liquid crystal display device or a color filter for a liquid crystal display device, a transflective liquid crystal display device or Simultaneous formation of a colored layer for a transmissive portion and a colored layer for a reflective portion in a color filter for a transflective liquid crystal display device, an overcoat layer and a gap adjusting layer in a color filter for a transflective liquid crystal display device or a transflective liquid crystal display device It is preferable to apply to simultaneous formation.

  In the case where the positive photosensitive resin is exposed using the gradation mask of the present invention, the spacer and the alignment control protrusion are simultaneously formed in the liquid crystal display device or the color filter for the liquid crystal display device, the liquid crystal display device or the liquid crystal display. Simultaneous formation of spacers having different heights in a color filter for a device, simultaneous formation of a colored layer for a transmissive part and a colored layer for a reflective part in a semi-transmissive liquid crystal display device or a color filter for a semi-transmissive liquid crystal display device, semi-transmissive liquid crystal It is preferably applied to the simultaneous formation of an overcoat layer and a gap adjusting layer in a color filter for a display device or a transflective liquid crystal display device.

  In addition, the size of the gradation mask 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, the size is 300 mm × 400 mm to 1,600 mm. It can be about x1,800 mm.

  As an exposure method when using the gradation mask of the present invention, when a simulation is performed as described above, a region at a predetermined distance from the boundary between the transmissive region and the semitransparent region is directed from the transmissive region to the semitransparent region. If the light intensity can be monotonously reduced and the light intensity distribution has no inflection point, it is not particularly limited. For example, a proximity exposure system, a mirror projection exposure system, etc. it can.

B. Next, a method for manufacturing a gradation mask according to the present invention will be described.
The method for producing a gradation mask of the present invention includes a transparent substrate and a semitransparent film formed in a pattern on the transparent substrate, the transparent region where the transparent substrate is exposed, and the semitransparent film on the transparent substrate. A method of manufacturing a gradation mask having a translucent region provided with a transparent film, and having a pattern in which the translucent region and the translucent region are adjacent to each other, as a material for forming the translucent film, When simulating the light intensity distribution at the time of exposure using a gradation mask, the transmission region and the semitransparent region are directed from the transmission region to the semitransparent region at a distance within 5 μm from the boundary between the transmission region and the semitransparent region. A semi-transparent film forming step of selecting a material whose light intensity monotonously decreases and having no inflection point in the light intensity distribution, and forming the semi-transparent film using the material. It is characterized by .

  As described above in “A. Tone mask”, in the present invention, when the above-described simulation is performed as a material for forming a translucent film, a predetermined distance from the boundary between the transmissive region and the translucent region is obtained. By selecting a material whose light intensity decreases monotonously from the transmissive area to the translucent area and does not have an inflection point in the light intensity distribution, Occurrence can be suppressed, and a gradation mask with high resolution can be obtained.

  Hereinafter, the translucent film forming step will be described.

1. Translucent film forming step The translucent film forming step in the present invention is performed when a light intensity distribution is simulated when exposure is performed using this gradation mask as a material for forming the translucent film. The light intensity monotonously decreases from the transmissive area toward the semi-transparent area at a distance within 5 μm from the boundary between the transmissive area and the semi-transparent area, and has no inflection point in the light intensity distribution. In this step, a material to be used is selected and the translucent film is formed using the material.

  In addition, when a simulation of light intensity distribution during exposure using a gradation mask is performed, in a region at a predetermined distance from the boundary between the transmissive region and the semi-transparent region, the transmissive region is directed to the semi-transparent region. The fact that the light intensity decreases monotonically and the light intensity distribution has no inflection point has been described in detail in the above “A. Tone mask”, and will not be described here.

  In the present invention, as a material for forming the translucent film, the transmittance at a wavelength of 365 nm of the translucent region is T (%), and the exposure light that has passed through the translucent region with respect to the exposure light that has passed through the transmissive region. It is preferable to select a material in which −δ / ln (T / 100) is 0.4 or less, where δ (rad) is the phase delay.

  When the transmissivity of the translucent region at a wavelength of 365 nm is T (%) and the phase delay of the exposure light that has passed through the translucent region with respect to the exposure light that has passed through the transmissive region is δ (rad). , -Δ / ln (T / 100) is 0.4 or less, since it has been described in detail in the above “A. Tone mask”, description thereof is omitted here.

In order to suppress the occurrence of defective exposure patterns, it is preferable to form a semi-transparent film so that the phase delay of the exposure light that has passed through the semi-transparent region with respect to the exposure light that has passed through the transmission region becomes a predetermined value or less. .
As a method of forming a translucent film so that the phase delay of the exposure light that has passed through the translucent area with respect to the exposure light that has passed through the transmissive area is a predetermined value or less, the film thickness of the translucent film or the translucent film Examples thereof include a method for controlling the refractive index of the material.

  The translucent film has been described in detail in the above “A. Tone mask”, and therefore the description thereof is omitted here.

2. Other Steps A method for producing a gradation mask according to the present invention includes the above-described translucent film forming step, and forms a translucent film on a transparent substrate in a pattern so that a transmission region and a translucent film are formed. The method is not particularly limited as long as the transmissive region and the translucent region can be arranged at predetermined positions so that the regions have adjacent patterns.

  Further, in the case of producing a gradation mask having a light shielding area in addition to the transmissive area and the semitransparent area, the gradation mask manufacturing method of the present invention includes the above-described semitransparent film forming step, In addition, by forming the translucent film and the light-shielding film in a pattern on the transparent substrate, the transmissive area, the translucent area, and the light-shielding area are formed at predetermined positions so that the transmissive area and the semi-transparent area have adjacent patterns. The method is not particularly limited as long as it can be arranged.

  In this case, for example, the gradation mask manufacturing method of the present invention includes a mask blank preparation step of preparing a mask blank in which a light shielding film is formed on a transparent substrate before the semitransparent film forming step, A first patterning step of patterning a part, and in the semi-transparent film forming step, a semi-transparent film is formed on the entire surface of the transparent substrate on which the patterned light-shielding film is formed. A second patterning step of patterning the light shielding film and the translucent film may be included after the film forming step. That is, you may have a mask blank preparation process, a 1st patterning process, a semi-transparent film | membrane film-forming process, and a 2nd patterning process.

  Further, for example, in the method of manufacturing a gradation mask according to the present invention, the translucent film is formed on the transparent substrate in the translucent film forming process, and the translucent film forming process and the translucent film are formed. A mask blank preparing step of preparing a mask blank in which a semi-transparent film and a light-shielding film are laminated in this order on a transparent substrate, and a semi-transparent film and a light-shielding film. You may have the 1st patterning process which patterns a part, and the 2nd patterning process which patterns only a light shielding film. That is, you may have a mask blank preparation process which has a translucent film forming process and a light shielding film forming process, a 1st patterning process, and a 2nd patterning process.

A general method can be applied to each step. A method for manufacturing a gradation mask is described in detail in, for example, Japanese Patent Application Laid-Open No. 2007-178649.
Further, the gradation mask manufactured according to the present invention is the same as that described in the above “A. gradation mask”, and therefore the 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 with reference to 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 chromium 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 chromium film. The etching time for the chromium 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. At this time, the thickness of the semitransparent film was 10 nm.
<Film formation conditions>
・ Gas flow ratio Ar: N ₂ = 5: 1
・ Power: 1.3kW
・ Gas pressure: 3.5mTorr
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.

(Production of color filter)
A glass substrate (Corning 1737 glass) having a size of 100 mm × 100 mm and a thickness of 0.7 mm was prepared as a substrate. After this substrate was washed according to a conventional method, a chromium thin film (thickness: 1000 mm) was formed on the entire surface of one side of the substrate by sputtering. A positive-type photosensitive resist (OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied onto the chromium thin film, and exposed and developed through a predetermined mask to form a resist pattern. Next, using this resist pattern as a mask, the chromium thin film was etched to form a black matrix having a line width of 20 μm and a pitch of 100 μm.

  Next, a negative photosensitive resin composition for a red pattern, a negative photosensitive resin composition for a green pattern, and a negative photosensitive resin composition for a blue pattern having the following compositions were prepared.

<Negative photosensitive resin composition for red pattern>
Red pigment (Ciba Specialty Chemicals chromophthal red A2B) 4.8 parts by weight Yellow pigment (BASF Pariotor Yellow D1819) 1.2 parts by weight Dispersant (Dispervic 161 manufactured by BYK Chemie) 3 1.0 part by weight / monomer (SR399 manufactured by Sartomer) 4.0 parts by weight Polymer I 5.0 parts by weight initiator (Irgacure 907 manufactured by Ciba Specialty Chemicals) 1.4 parts by weight initiator (2, 2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole) 0.6 part by weight / solvent (propylene glycol monomethyl ether acetate) 80.0 parts by weight

<Negative photosensitive resin composition for green pattern>
Green pigment (Avisia Monastral Green 9Y-C) 4.2 parts by weight Yellow pigment (BASF Paliotor Yellow D1819) 1.8 parts by weight Dispersant (Bicchemy Disperbic 161) 3.0 Parts by weight / monomer (SR399, manufactured by Sartomer) 4.0 parts by weight, polymer I 5.0 parts by weight, initiator (Irgacure 907, manufactured by Ciba Specialty Chemicals) 1.4 parts by weight, initiator (2,2 ′ -Bis (o-chlorophenyl) -4,5,4 ', 5'-tetraphenyl-1,2'-biimidazole) 0.6 parts by weight / solvent (propylene glycol monomethyl ether acetate) 80.0 parts by weight

<Negative photosensitive resin composition for blue pattern>
Blue pigment (BASF Heliogen Blue L6700F) 6.0 parts by weight Pigment derivative (Abyssia Solsperse 5000) 0.6 parts by weight Dispersant (Bic Chemie Dispersic 161) 2.4 parts by weight Monomer (SR399, manufactured by Sartomer) 4.0 parts by weight, Polymer I, 5.0 parts by weight, initiator (Irgacure 907, manufactured by Ciba Specialty Chemicals) 1.4 parts by weight, initiator (2,2'-bis (o -Chlorophenyl) -4,5,4 ', 5'-tetraphenyl-1,2'-biimidazole) 0.6 parts by weight / solvent (propylene glycol monomethyl ether acetate) 80.0 parts by weight

  The polymer I is based on 100 mol% of a copolymer of benzyl methacrylate: styrene: acrylic acid: 2-hydroxyethyl methacrylate = 15.6: 37.0: 30.5: 16.9 (molar ratio). 2-methacryloyloxyethyl isocyanate was added at 16.9 mol%, and the weight average molecular weight was 42500.

Next, a negative photosensitive resin composition for red pattern is applied by spin coating so as to cover the black matrix on the glass substrate, exposed and developed through a photomask for red pattern, and the red pattern is formed. Formed. The red pattern was rectangular (100 μm × 300 μm).
Then, the green pattern and the blue pattern were formed by the same operation using the negative photosensitive resin composition for the green pattern and the negative photosensitive resin composition for the blue pattern. As a result, a colored layer in which a red pattern, a green pattern, and a blue pattern were arranged was formed.

  Next, a transparent electrode layer (thickness 1500 mm) made of indium tin oxide (ITO) was formed by sputtering so as to cover the black matrix and the colored layer.

Next, a positive photosensitive resin composition (LC100VL, manufactured by Rohm and Haas, solid content 15%) was applied on the transparent electrode layer by spin coating, dried under reduced pressure, and prebaked at 100 ° C. for 3 minutes. Then, it exposed on the following conditions through said gradation mask.
<Exposure conditions>
・ Exposure dose: 50 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 spacers and alignment control protrusions simultaneously.

[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 sputtered under the following conditions The film was formed. At this time, the thickness of the chromium oxynitride carbide film was 33 nm.
<Film formation conditions>
Gas flow ratio Ar: CO ₂ : N ₂ = 1: 0.5: 0.5
・ Power: 1.5kW
・ Gas pressure: 3mTorr

(Production of color filter)
A color filter was produced in the same manner as in Example 1.

[Evaluation]
For the gradation masks of Example 1 and Comparative Example 1, the light intensity distribution was obtained by simulation. The simulation conditions are: exposure gap: 150 μm, Collimation: 1.5 °, exposure wavelength: 365 nm, transmissivity of translucent area T: 30% (365 nm), exposure passing through translucent area with respect to exposure light passing through transmissive area The phase delay of light (phase difference) δ: 0.02 rad or 1.22 rad, the line width of the translucent region: 15 μm, the exposure method: the proximity exposure method. The simulation result is shown in FIG.
In the gradation mask of Example 1 (FIG. 7A), the light intensity monotonously decreases from the transmissive region to the semi-transparent region in a region within a distance of 5 μm from the boundary between the transmissive region and the semi-transparent region. It was found that the light intensity distribution has no inflection point. On the other hand, in the gradation mask of Comparative Example 1 (FIG. 7B), the light intensity monotonously decreases from the transmissive region to the semitransparent region in a region within 5 μm from the boundary between the transmissive region and the semitransparent region. Without having an inflection point in the light intensity distribution.

  The cross-sectional shapes of the spacers and alignment control protrusions formed using the gradation masks of Example 1 and Comparative Example 1 were observed with a scanning electron microscope, and the dimensions were measured. In addition, the cross-sectional shape of the spacer is a circle with a truncated cone, the cross-sectional shape of the alignment control protrusion is a circle with a kamaboko shape, and the unintentional pattern remains around the protrusion is x. did. The evaluation results are shown in Table 1.

  By using the gradation mask of Example 1 for the exposure process, it was possible to form a pattern having an optimum shape and size as the spacer and the alignment control protrusion.

[Example 2]
As shown in FIG. 11, the transparent substrate 2 includes a semitransparent region 12 in which the semitransparent film 3 is provided, and a transparent region 13 in which the transparent substrate 2 is exposed. For the gradation mask 1 having an adjacent pattern, the light intensity distribution was obtained by simulation. FIG. 11A is a cross-sectional view taken along line EE of FIG.

  The simulation conditions are: exposure gap: 150 μm, Collimation: 1.5 °, exposure wavelength: 365 nm, transmissivity of translucent area T: 10% to 90% (365 nm), translucent area for exposure light passing through the transmissive area The phase delay (phase difference) δ of the passed exposure light δ: 0.01 rad to 1.28 rad, the line width of the translucent region: 15 μm, the exposure method: the proximity exposure method.

  From the simulation results, the shape of the light intensity distribution was evaluated. Here, in a region within a distance of 5 μm from the boundary between the transmission region and the translucent region, the light intensity monotonously decreases from the transmission region to the semitransparent region, and the light intensity distribution has no inflection point. And the others were marked with x. Table 2 shows the evaluation of the shape of the light intensity distribution and the value of −δ / ln (T / 100).

  In the simulation, when −δ / ln (T / 100) is 0.4 or less, the region is within a distance of 5 μm from the boundary between the transmissive region and the semitransparent region, and is directed from the transmissive region to the semitransparent region. It was found that the light intensity decreased monotonously and had no inflection point in the light intensity distribution.

[Example 3]
(Production of gradation mask)
The light-shielding film and the semi-transparent film are formed so as to have a light-shielding region for forming a spacer having a high height and a semi-transparent region for forming a spacer having a low height. A gradation mask was produced in the same manner as in Example 1 except that the pattern was drawn.

(Production of color filter)
A color filter was produced in the same manner as in Example 1 except that instead of forming the spacer and the alignment control protrusion, the spacer having a different height was formed using the gradation mask.

[Comparative Example 2]
(Production of gradation mask)
The light-shielding film and the semi-transparent film are formed so as to have a light-shielding region for forming a spacer having a high height and a semi-transparent region for forming a spacer having a low height. A gradation mask was prepared in the same manner as Comparative Example 1 except that the pattern was drawn.

(Production of color filter)
A color filter was produced in the same manner as in Example 1 except that instead of forming the spacer and the alignment control protrusion, the spacer having a different height was formed using the gradation mask.

[Evaluation]
For the gradation masks of Example 3 and Comparative Example 2, the light intensity distribution was obtained by simulation. The simulation conditions are: exposure gap: 150 μm, Collimation: 1.5 °, exposure wavelength: 365 nm, transmissivity of translucent area T: 15% (365 nm), exposure through the translucent area with respect to the exposure light that has passed through the transmissive area. Light phase delay (phase difference) δ: 0.03 rad or 1.93 rad, diameter of translucent region: 30 μm, exposure method: proximity exposure method. The simulation result is shown in FIG.
In the gradation mask of Example 3 (FIG. 13A), the light intensity monotonously decreases from the transmissive region to the semi-transparent region in a region within a distance of 5 μm from the boundary between the transmissive region and the semi-transparent region. It was found that the light intensity distribution has no inflection point. On the other hand, in the gradation mask of Comparative Example 2 (FIG. 13B), the light intensity monotonously decreases from the transmissive region to the semitransparent region in a region within 5 μm from the boundary between the transmissive region and the semitransparent region. Without having an inflection point in the light intensity distribution.

  The cross-sectional shapes of the spacers having different heights formed using the gradation masks of Example 3 and Comparative Example 2 were observed with a scanning electron microscope, and the dimensions were measured. In addition, as for the cross-sectional shape of the spacer, a circle having a truncated cone is indicated by ◯, and a spacer having an unintended pattern remaining around the protrusion is indicated by ×. The evaluation results are shown in Table 3.

  By using the gradation mask of Example 3, it was possible to form a pattern having an optimum shape and dimensions as spacers having different heights.

It is a schematic diagram which shows an example of the gradation mask of this invention. It is a figure for demonstrating the simulation of light intensity distribution. It is a graph which shows a simulation result. It is a schematic sectional drawing which shows an example of the use of the conventional gradation mask. It is a schematic sectional drawing which shows an example of the use of the gradation mask of this invention. It is a schematic diagram which shows the other example of the gradation mask of this invention. It is a graph which shows a simulation result. It is a schematic sectional drawing which shows the other example of the use of the conventional gradation mask. It is a schematic sectional drawing which shows the other example of the use of the gradation mask of this invention. It is a schematic diagram which shows the other example of the gradation mask of this invention. 6 is a schematic diagram illustrating a gradation mask in Example 2. FIG. It is a schematic diagram which shows an example of the conventional gradation mask. It is a graph which shows a simulation result.

Explanation of symbols

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 (4)

A transparent substrate; a translucent film formed in a pattern on the transparent substrate; a transparent region where the transparent substrate is exposed; and a translucent region where the translucent film is provided on the transparent substrate. A gradation mask having a pattern in which the transmissive region and the translucent region are adjacent to each other,
When a simulation of the light intensity distribution at the time of exposure using the gradation mask is performed, the region from the transmission region to the semi-transparent region is within a distance of 5 μm from the boundary between the transmission region and the semi-transparent region. the light intensity decreases monotonically toward state, and are not that does not have an inflection point in the light intensity distribution,
When the transmissivity of the translucent region at a wavelength of 365 nm is T (%), and the phase delay of the exposure light that has passed through the translucent region with respect to the exposure light that has passed through the transmissive region is δ (rad), − A gradation mask, wherein δ / ln (T / 100) is 0.4 or less . The gradation mask according to claim 1, wherein the translucent film includes at least one metal selected from the group consisting of chromium, titanium, nickel, nickel alloy, and tantalum. A light shielding film is formed in a pattern on the transparent substrate, has a light shielding region where the light shielding film is provided on the transparent substrate, and the semitransparent region is provided only with the semitransparent film on the transparent substrate. The gradation mask according to claim 1 , wherein the gradation mask is a region. A transparent substrate; a translucent film formed in a pattern on the transparent substrate; a transparent region where the transparent substrate is exposed; and a translucent region where the translucent film is provided on the transparent substrate. And a method of manufacturing a gradation mask having a pattern in which the transmissive region and the translucent region are adjacent to each other,
When a simulation of the light intensity distribution at the time of exposure using the gradation mask is performed, the region from the transmission region to the semi-transparent region is within a distance of 5 μm from the boundary between the transmission region and the semi-transparent region. A semi-transparent film forming step of selecting a material whose light intensity decreases monotonously and having no inflection point in the light intensity distribution, and forming the semi-transparent film using the material. And
The transmittance of the material at the wavelength of 365 nm in the semi-transparent region is T (%), and the phase delay of the exposure light that has passed through the semi-transparent region with respect to the exposure light that has passed through the transmission region is δ (rad). In this case, the gradation mask manufacturing method is characterized in that the material is such that -δ / ln (T / 100) is 0.4 or less .

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