TW202340761A - Proximity exposure photomask and method for producing color filter - Google Patents

Abstract

The present disclosure provides a proximity exposure photomask comprising a transparent substrate; and a light-shielding film placed on the transparent substrate, wherein the light-shielding film includes a light-shielding main portion including a roughly polygonal shape or roughly circular shape opening; and a light-shielding auxiliary pattern placed on an inner side of the opening of the light-shielding main portion and formed with a space from the light-shielding main portion, and the light-shielding film has a phase-shifting function to shift a phase for 180° ± 45° with respect to an exposure light, and is a phase-shifting film whose transmittance of the exposure light is 1% or more and 10% or less.

Description

Method for manufacturing photomask and color filter for proximity exposure

The invention relates to a manufacturing method of a photomask for proximity exposure and a color filter.

Previously, the photolithography method was used to form the colored layer of the color filter of the liquid crystal display device. The photolithography method is to perform pattern exposure on the photosensitive resin layer formed on the substrate. After the exposure, the photosensitive resin layer is exposed. The resin layer is developed to form a target pattern. In photolithography, light is generally irradiated through a photomask.

At this time, in order to prevent damage caused by the close contact between the mask and the object to be exposed, or to prevent defects caused by dust adhering to the mask, exposure is often performed with a gap between the mask and the object to be exposed, that is, close proximity formula (close) exposure. However, when such a gap is provided, there is a problem that a shape aiming at a fine pattern cannot be formed due to Fresnel diffraction phenomenon or the like.

In recent years, a projection transfer exposure method in which a projection lens is provided between a photomask and a substrate to be processed is sometimes used. According to the projection transfer exposure method, the pattern image can be transferred to the object to be exposed, thereby obtaining a resolution equivalent to the exposure wavelength. However, the projection transfer exposure method requires a high-precision lens and the exposure equipment costs a lot. Therefore, a mask capable of forming a shape targeting fine patterns by proximity exposure is required.

Therefore, attempts have been made to improve the resolution in the proximity exposure method by designing the mask pattern. For example, Patent Document 1 discloses a technology for achieving miniaturization using a proximity exposure machine using OPC (Optical Proximity Correction). Specifically, a photomask is disclosed, which is provided with: a light-transmitting substrate; a light-shielding portion provided on the above-mentioned light-transmitting substrate and blocking exposure light; and a main pattern portion provided in the above-mentioned light-shielding portion in a desired direction. The area corresponding to the pattern is composed of the opening of the above-mentioned light shielding part; and the auxiliary pattern part is along the peripheral part of the position corresponding to the above-mentioned desired pattern in the light-shielding part and forms the edge of the outline part of the above-mentioned desired pattern. The arrangement includes a plurality of in-phase auxiliary patterns composed of openings for transmitting in-phase light having the same phase as the light passing through the main pattern part. [Prior technical literature] [Patent Document]

Patent Document 1: Patent No. 6118996

[Problem to be solved by the invention]

As the resolution of liquid crystal panels increases, the pixel size also decreases, and the pattern size of the pillars (photosensitive spacers) that maintain the cell gap between the color filter and the TFT (thin film transistor) substrate is also required. The miniaturization and the increase of the cone angle, etc.

Several methods can be considered to improve the transfer size and taper angle of the column using proximity exposure. For example, there are methods to reduce the exposure gap. However, in a large mask, the deflection of the mask cannot be ignored and is close to the limit of the exposure gap. In addition, there are methods of changing the resist, but the resolution of the resist is also close to the limit. Even if it is prepared, it is difficult to obtain the approval of the end user for material change, and it is disadvantageous in terms of cost. Furthermore, there are methods such as reducing the exposure collimation angle. However, if an HRU (High Resolution Unit) using a fly-eye lens or a rod lens is used, the exposure illumination will be reduced, the lead time will be extended, and the production efficiency will be reduced. .

In addition, when an opaque light-shielding film is used as described in Patent Document 1, the effect of miniaturizing the size of the transfer pattern is small. In addition, Patent Document 1 describes providing a phase shift film in the opening, but the steps, film formation costs, and production preparation time are long, and it cannot meet the requirements of the photomask.

The present invention was made in view of the above circumstances, and its main purpose is to provide a photomask capable of miniaturizing the size of the transfer pattern and increasing the taper angle through proximity exposure. [Technical means to solve problems]

One embodiment of the present invention provides a photomask for proximity exposure, which is a photomask for proximity exposure and has a transparent substrate and a light-shielding film arranged on the transparent substrate. The light-shielding film has: a light-shielding main part, It is formed with a substantially polygonal or substantially circular opening; and a light-shielding auxiliary pattern, which is disposed inside the opening of the light-shielding main part and formed at a distance from the light-shielding main part; the light-shielding film has a phase-relative A phase shift film that shifts the exposure light by 180 degrees ±45 degrees and has a transmittance of 1% or more and 10% or less.

In the proximity exposure mask of the present invention, it is preferable that the rising angle of the peak of the light intensity distribution of the light passing through becomes larger relative to a reference mask aiming at forming a transfer pattern with the same bottom size. method, configure the above-mentioned light-shielding auxiliary pattern.

In the proximity exposure mask of the present invention, it is preferable that the diameter of the opening is 10 μm or more and 20 μm or less.

In the proximity exposure mask of the present invention, it is preferable that the above-mentioned exposure light is a mixed wavelength of j line (313 nm), i line (365 nm), h line (405 nm) and g line (436 nm). Light.

One embodiment of the present invention provides a method for manufacturing a color filter, characterized in that the color filter is provided with a black matrix, colored pixels, and photosensitive spacers on a transparent substrate for color filters, and the above-mentioned color filter The sheet manufacturing method includes a photospacer forming step of forming a photospacer including a columnar pattern corresponding to the opening in the light-shielding main portion using the proximity exposure mask. [Effects of the invention]

The present invention can provide a mask capable of miniaturizing the size of a transfer pattern and improving the taper angle by proximity exposure.

Embodiments of the present invention will be described below with reference to drawings and the like. However, the present invention can be implemented in many different ways and should not be construed as being limited to the description of the illustrated embodiments below. In addition, in order to make the drawings more clear, the width, thickness, shape, etc. of each part may be shown schematically compared with the actual form. However, this is only an example and does not limit the interpretation of the present invention. In addition, in this specification and each drawing, the same reference numerals are attached to the same elements as those in the previously shown drawings, and detailed descriptions may be appropriately omitted.

In this specification, when expressing the arrangement of other members on a certain member, when it is only expressed as "upper" or "lower", unless otherwise specified, it includes the manner of being connected to a certain member. There are two situations: arranging other components directly above or directly below, and arranging other components above or below a certain component through another component. In addition, in this specification, when expressing the arrangement of other members on the surface of a certain member, when it is only expressed as "face side" or "face", unless otherwise specified, it includes those connected to a certain member. There are two situations: the situation of arranging other components directly above or directly below, and the situation of arranging other components above or below a certain component and then through another component.

Hereinafter, the photomask for proximity exposure of the present invention will be described in detail. Furthermore, in this manual, "mask for proximity exposure" is sometimes referred to as "mask" for short.

A. Mask for proximity exposure Fig. 1(A) is a schematic plan view showing an example of the photomask of the present invention, and Fig. 1(B) is a cross-sectional view taken along line AA of Fig. 1(A). As shown in FIG. 1 , the photomask 1 for proximity exposure of the present invention has a transparent base material 2 and a light-shielding film 3 arranged on the transparent base material 2 . The light-shielding film 3 has a light-shielding main portion 31 having a substantially polygonal or substantially circular opening O; and a light-shielding auxiliary pattern 32 arranged at a distance from the light-shielding main portion 31 in the opening. The light-shielding film 3 is a phase shift film that shifts the phase of the exposure light of the exposure mask by 180 degrees ± 45 degrees, and has a transmittance of 1% to 10% for the exposure light. In the proximity exposure mask 1 of the present invention shown in FIG. 1 , the area of the opening O is divided into an inner transparent area 42 and an outer transparent area 41 by the light-shielding auxiliary pattern 32 .

According to the present invention, a phase shift film that shifts the phase of the exposed light by 180 degrees ± 45 degrees is used as the light-shielding film, and a light-shielding auxiliary pattern is formed inside the opening of the main light-shielding portion, thereby making it possible to achieve the desired transformation. The taper angle can be increased by miniaturizing the size of the printed pattern (for example, the columnar pattern corresponding to the opening). It is presumed that the reason is that by using the above-mentioned phase shift film as a light-shielding film, light passing through the phase shift film and light passing through the transparent area in the opening interfere with each other outside the boundary portion of the desired transfer pattern. The light intensity is weakened, and near the center of the desired transfer pattern, the light passing through the transparent areas separated by the light-shielding auxiliary pattern of the opening interferes with each other and is intensified, whereby the light passing through shows a steep light intensity distribution. Therefore, according to the proximity exposure mask of the present invention, it is possible to reduce the size of the transfer pattern or to increase the taper angle. Furthermore, since the variation in the size of the transfer pattern with respect to the exposure gap variation can be reduced, the transfer pattern can be formed with high accuracy even when the photomask is large. Furthermore, since the light intensity near the center of the desired transfer pattern becomes large, even if a HRU (High Resolution Unit) is used to reduce the exposure collimation angle, a decrease in production efficiency can be suppressed.

Figure 2(A) shows the light amplitude at the imaging surface of the mask (specifically, the surface of the photosensitive resin layer) when the light-shielding film of the proximity exposure mask is a 180-degree phase shift film with a transmittance of 5.2%. Distribution, Figure 2(B) shows the light intensity distribution on the imaging surface of the mask. As shown in Figure 2, it was confirmed that by using the phase shift film, outside the boundary portion of the desired transfer pattern (specifically, the position where the light intensity corresponds to the resolution threshold of the resist) , the light L2 passing through the phase shift film interferes with the light L1 passing through the transparent area in the opening, and the light intensity outside the boundary portion is weakened.

Furthermore, when the photosensitive resin layer is patterned using the proximity exposure mask of the present invention, the pattern corresponding to the light-shielding auxiliary pattern is not resolved, and only the pattern corresponding to the shape of the opening is formed.

As will be described later, the proximity exposure mask in the present invention is preferably based on the rising angle of the peak of the light intensity distribution of the light passing through it relative to a reference mask aiming to form a transfer pattern with the same bottom size. To make it larger, configure the shading auxiliary pattern. Here, the above-mentioned reference mask refers to a mask that has an opening corresponding to the transfer pattern formed on a transparent substrate and is substantially opaque to light, and does not have an auxiliary pattern formed inside the opening.

The shape or position of this shading auxiliary pattern can be determined by simulation of light intensity distribution. The simulation of light intensity distribution is based on ordinary Fresnel diffraction. According to the following equation (1), the integrated value of the spherical wave from each point of the opening (transparent area) of the corresponding proximity exposure mask can be calculated, which is the point P on the substrate. The amplitude E _P of light and the light intensity I at point P are calculated based on the following equation (2).

3 is a diagram for explaining the calculation of the light intensity distribution at point P on the substrate 52 by the following equation (1), and shows an arbitrary point Q of the opening of the proximity exposure mask 1 and the substrate. A model diagram of the positional relationship of any point P on 52. In FIG. 3 , point S is the position on the substrate 52 when the exposure light 53 passes through the point Q and proceeds straight.

[Number 1]

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 The angle formed by line segment QS and line segment QP, r is the distance from point Q to point P, and i is the imaginary unit.

I=E _P ×E _P ^* (2) Here, in the equation (2), E _P ^* is the conjugate complex number of E _P. In addition, the above calculation is performed by a computer by dividing the opening of the proximity exposure mask into limited micro intervals.

For example, when there is one light-shielding auxiliary pattern arranged inside the opening and the shape of the light-shielding auxiliary pattern is a continuous circular ring, if the diameter A of the opening and the light-shielding auxiliary pattern are as shown in FIG. 4 If the width B of 32 and the inner diameter C of the light-shielding auxiliary pattern 32 satisfy the following formula, the light intensity at the center of the transfer pattern can be reliably increased, and the light intensity at the boundary of the transfer pattern (specifically, can become a considerable Reduce the light intensity outside the resist's resolution threshold (light intensity position).

A×S1+S2-S3≦C≦A×S1+S2+S3 (3) (In the formula, S1, S2, S3 are as follows. S1＝(-0.0360×B ² +0.185×B+0.829) S2＝(0.775×B ² -5.97×B-0.777) S3＝(0.0938×B ² -1.31×B+5.26))

Figure 5 shows the relationship between the base size and the slope value of the transfer pattern (columnar pattern) when using the photomask of the present invention that satisfies the above formula (3) through simulation. Furthermore, the transfer conditions are: Collimation half angle: 0.7 degrees, light source of exposure device: j line (313 nm), i line (365 nm), h line (405 nm), g line (436 nm) 4-wavelength mixed light source, exposure gap: 200 μm. Similarly, the relationship between the bottom size and the slope value of the columnar pattern is also obtained for the reference mask through simulation.

As shown in Figure 5, in the reference mask, when the base size (μm) under the transfer pattern is small, especially when the base size under the transfer pattern is 10 μm or less, it can be confirmed that the slope value is significantly reduced. . On the other hand, it can be confirmed that the slope value of the mask of the present invention is higher than that of the reference mask at all points satisfying the above equation (3). Furthermore, the slope value is the slope of the tangent line in the resist resolution threshold in the simulation result of the light intensity distribution.

In this way, when the photomask of the present invention is used, the slope value becomes high, that is, the taper angle of the transfer pattern is close to vertical. Furthermore, the taper angle refers to the angle between the side surface of the layer having a tapered shape and the bottom surface of the layer.

Furthermore, depending on the use of the transfer pattern, the proximity exposure mask in the present invention may not necessarily be based on the light intensity distribution of the light passing through it relative to a reference mask targeting a transfer pattern with the same bottom size. In order to increase the rising angle of the wave crest, a light-shielding auxiliary pattern is configured.

Hereinafter, each structure of the photomask of the present invention will be described in detail.

1.Light-shielding main part The light-shielding main part of the photomask in the present invention is arranged on the transparent base material, and is formed with a substantially polygonal or substantially circular opening. The opening is an area corresponding to the desired transfer pattern (design pattern). The number of openings in the light-shielding main part is not particularly limited, and may be one or a plurality of openings.

The shape of the opening is appropriately selected according to the type of proximity exposure mask, use, etc. In the present invention, a substantially circular shape refers to a circle (a perfect circle) and an elliptical shape in which the maximum diameter when the minimum diameter is 1 is in the range of more than 1 and 3.0 or less. Moreover, a rough polygon refers to a regular polygon, a polygon in which the length of the longest straight line is in the range of greater than 1 and less than 3.0 when the length of the smallest straight line among the straight lines drawn from each corner through the center is set to 1.

In the present invention, the diameter of the opening is, for example, 10 μm or more. On the other hand, it is, for example, 20 μm or less, preferably 15 μm or less. As a specific range, for example, it is about 10 μm or more and 20 μm or less, and particularly preferably it is about 10 μm or more and 15 μm or less. Furthermore, when the opening is substantially polygonal, the diameter of the opening refers to the length of a straight line drawn from each corner and passing through the center. Moreover, in the case of a polygon other than an ellipse or a regular polygon, the minimum diameter is preferably within the above range.

2. Blackout auxiliary pattern The light-shielding auxiliary pattern of the photomask for proximity exposure in the present invention is spaced apart from the light-shielding main part and formed inside the opening of the light-shielding main part. This kind of light-shielding auxiliary pattern is preferably based on the rising angle of the peak of the light intensity distribution of the passing light when a reference mask targeting a transfer pattern with the same bottom size is exposed under the same conditions. Large width, size and spacing arrangement from the main part of the shading. The above same conditions refer to the same exposure wavelength, exposure gap and exposure collimation angle.

The number of light-shielding auxiliary patterns arranged inside the opening may be one, or two or more.

A mask for proximity exposure when there is one light-shielding auxiliary pattern arranged inside the opening will be described. As shown in FIG. 1 , the light-shielding auxiliary pattern 32 is preferably arranged in such a manner that the light passing through the inner transparent region 42 on the inside of the light-shielding auxiliary pattern 32 in the opening O is combined with the light passing through the light-shielding auxiliary pattern 32 and The light in the outer transparent area 41 , which is the gap between the light-shielding main portions 31 , interferes, so that the light intensity near the center of the transfer pattern increases.

A mask for proximity exposure when there are two light-shielding auxiliary patterns arranged inside the opening will be described. In the proximity exposure mask shown in FIG. 6 , a first light-shielding auxiliary pattern 32 a and a second light-shielding auxiliary pattern 32 b are formed inside the opening O from the light-shielding main portion 31 side. The second light-shielding auxiliary pattern and the first light-shielding auxiliary pattern are preferably arranged in such a manner that they pass through the transparent area 43 inside the second light-shielding auxiliary pattern 32b, the first light-shielding auxiliary pattern 32a, and the second light-shielding auxiliary pattern. The light in the transparent area 42, which is the gap between 32b, and the transparent area 41, which is the gap between the first light-shielding auxiliary pattern 32a and the light-shielding main part 31, interferes, so that the light intensity near the center of the transfer pattern increases.

The specific size or width of the light-shielding auxiliary pattern and the distance between the light-shielding main part and the light-shielding auxiliary pattern can be determined by simulation of the light intensity distribution based on the above-mentioned Fresnel diffraction.

Specific shapes of the light-shielding auxiliary pattern include various shapes such as a circular annular shape and a polygonal annular shape. In addition, the outer shape of the light-shielding auxiliary pattern may be similar to the shape of the opening of the light-shielding main part, or may not be similar, but is preferably a similar shape. This is because the shape of the transferred pattern is stable. In addition, the shape of the opening of the light-shielding auxiliary pattern may be the same shape as the shape of the opening of the light-shielding main part, but it may not be the same shape.

Furthermore, it is preferable that the center of the light-shielding auxiliary pattern and the opening in the light-shielding main part are concentric. Here, the concentricity of the center of the light-shielding auxiliary pattern and the center of the opening of the light-shielding main part means that the center of the light-shielding auxiliary pattern is located within a circle with a radius of 1 μm from the center of the opening of the light-shielding main part.

The light-shielding auxiliary pattern can be formed continuously or discontinuously.

When there is one light-shielding auxiliary pattern arranged inside the opening, its width ((B) in FIG. 4) is preferably 0.5 μm or more, and more preferably 0.8 μm or more. On the other hand, it is preferably 8.0 μm or less, and particularly preferably 7.0 μm or less. As a specific range, the range is preferably from 0.5 μm to 8 μm, and particularly preferably from 0.8 μm to 7.0 μm. When the width of the light-shielding auxiliary pattern does not meet the above range, the desired effect of the light-shielding auxiliary pattern cannot be obtained. Therefore, when it exceeds the above range, when using a proximity exposure mask for exposure and development, there is a possibility that it will be damaged. The danger of interpretation.

In addition, the inner diameter of the light-shielding auxiliary pattern ((C) in FIG. 4) is preferably 1 μm or more, and particularly preferably 2 μm or more. On the other hand, it is preferably 19 μm or less, and particularly preferably 11 μm or less. As a specific range, the range is preferably from 1 μm to 19 μm, and particularly preferably from 2 μm to 11 μm.

In addition, the width of the gap (transparent area) between the light-shielding main part and the light-shielding auxiliary pattern is preferably 1 μm or more, and particularly preferably 1.5 μm or more. On the other hand, it is preferably 4 μm or less, and particularly preferably 2.0 μm or less. As a specific range, the range is preferably from 1 μm to 4 μm, and particularly preferably from 1.5 μm to 2.0 μm.

Moreover, when there are two light-shielding auxiliary patterns (the first light-shielding auxiliary pattern and the second light-shielding auxiliary pattern) arranged inside the opening, the widths of the first light-shielding auxiliary pattern and the second light-shielding auxiliary pattern are preferably 0.8. μm or above. On the other hand, it is preferably 3.0 μm or less, and particularly preferably 2.0 μm or less. As a specific range, the range is preferably from 0.8 μm to 3.0 μm, and particularly preferably from 0.8 μm to 2.0 μm.

In addition, the width of the gap (transparent area) between the light-shielding main part and the first light-shielding auxiliary pattern is preferably 1 μm or more. On the other hand, it is preferably 4 μm or less, and particularly preferably 2.0 μm or less. As a specific range, the range is preferably from 1 μm to 4 μm, and particularly preferably from 1.0 μm to 2.0 μm.

Furthermore, the width of the gap (transparent area) between the first light-shielding auxiliary pattern and the second light-shielding auxiliary pattern is preferably 1.0 μm or more. On the other hand, it is preferably 4.0 μm or less, and particularly preferably 2.0 μm or less. As a specific range, the range is preferably from 1.0 μm to 4.0 μm, and particularly preferably from 1.0 μm to 2.0 μm.

In addition, the thickness of the light-shielding auxiliary pattern is preferably the same as the thickness of the light-shielding main part. This is because, as described above, during the manufacturing process of the proximity exposure mask of the present invention, the light-shielding auxiliary pattern and the light-shielding main portion can be formed together.

3.Light-shielding film The light-shielding film in the present invention includes the above-mentioned light-shielding main part and the above-mentioned light-shielding auxiliary pattern. In the present invention, the light-shielding film has a phase shifting effect of shifting the phase of the exposure light that has passed through the transparent area by 180 degrees ± 45 degrees, and has a transmittance of more than 1%, preferably more than 4%, relative to the exposure light. . On the other hand, it has a transmittance of 10% or less, preferably 7% or less. The specific range of the transmittance is 1% to 10%, preferably 4% to 7%. Furthermore, in the present invention, the exposure light may be any one of j-line (313 nm), i-line (365 nm), h-line (405 nm), and g-line (436 nm) or include these wavelengths A range of mixed wavelengths of light.

By using a light-shielding film having such a phase-shifting effect, the light that passes through exhibits a steep light intensity distribution as described above. In addition, the above-mentioned transmittance can be measured using the transmittance of the transparent substrate mentioned later as a reference (100%). In addition, a UV/visible spectrophotometer (for example, Hitachi U-4000) can be used for the measurement of the above-mentioned average transmittance. The measurement conditions of the UV/visible spectrophotometer (Hitachi U-4000) are summarized in Table 1.

[Table 1] device Common name UV·visible spectrophotometer manufacturer Hitachi Model U4000 Measurement conditions light source Deuterium lamp + halogen lamp Measurement mode Wavelength scan data mode ABS Measure wavelength 300～700nm Scan speed: 300nm/min Sampling interval: 0.50nm Slit: 5.00nm Photomultiplier tube voltage: Auto 1 Light source switching mode: Automatic switching Light source switching wavelength: 340.00nm High resolution measurement: Off Near infrared scanning speed: 750nm/min Near infrared slit: automatic control Near infrared PbS sensitivity: 2 Near-infrared detector switching correction: No correction Near-infrared detector switching wavelength: 850nm Near infrared light control mode: fixed Unit length: 10.0mm parsing conditions Data processing project Savitsky-Golay Smoothed Smoothing times: 3 Number of data: 7 Times: 1 Measurement sample condition The medium of metal film on Qz glass is Air. The transmittance of the membrane is converted to a value based on Qz. size 6025 Sampling method One monitoring board is distributed together with the measurement and product Pretreatment method Rinse with pure water and spin dry Measurement site 1 point in the center of 6025 substrate Number of measurements N=5 Measuring direction With the film surface placed on a horizontal platform, light is irradiated from a light source pointing directly downward at an angle of 0 degrees with respect to the optical axis, and the value of the light received by the light receiving part on the glass surface side is measured.

In addition, the transmittance at the mixed wavelength of j line (313 nm), i line (365 nm), h line (405 nm), and g line (436 nm) is the value of the wavelength with the highest transmittance among the mixed wavelengths.

Regarding the structure of the light-shielding film, a single-layer film can be selected from a material having a film thickness that shifts the phase of the exposure light by 180 degrees ± 45 degrees and obtains the above-mentioned transmittance. In addition, the form may include a phase adjustment layer mainly composed of a high transmittance material that shifts the phase by 180 degrees ± 45 degrees, and a transmittance adjustment layer mainly composed of a low transmittance material that determines the transmittance. 2-story structure.

When the light-shielding film is composed of a single layer, 1% to 10% can be obtained by selecting a thickness d with a high refractive index n (usually above 1.5) and a phase shift of 180 degrees ± 45 degrees for the exposure light of wavelength λ. The material has the desired transmittance within the range. Examples of materials for the translucent phase shift film composed of such a single layer include chromium oxynitride (CrON), molybdenum silicon nitride (MoSiN), molybdenum silicon oxynitride (MoSiON), silicon oxynitride (SiON), and oxynitride. Titanium (TiON) changes the oxygen or nitrogen content to adjust the transmittance.

The light-shielding film is required to have a film thickness that shifts the phase of the exposure light by 180 degrees ± 45 degrees. The film thickness d of the main part of the light-shielding part, the refractive index n, the wavelength λ of the light of exposure, and the exposure light pass through the main part of the light-shielding part and the auxiliary light-shielding part. There is a relationship between the phase difference Φ generated by the pattern and Φ = 2π(n-1)d/λ. The phase difference reversal is due to Φ = π, so the film thickness d of the phase difference reversal is λ/2(n- 1). Furthermore, the phase difference is not limited to 180 degrees. As long as it is within the range of 180 degrees ± 45 degrees, a sufficient phase shift effect can be obtained.

When the light-shielding film is composed of two layers, first, as the material of the phase adjustment layer, a material with a high refractive index and high light transmittance at the exposure wavelength is selected to form a layer that inverts the phase, and then the transmittance at the exposure wavelength is selected. The lower material is used as the material of the transmittance adjustment layer, and the thickness of each film is adjusted so that the two layers of film as a whole can reverse the phase of the exposed light and make the transmittance reach the desired value. As the material of the phase adjustment layer, chromium oxynitride (CrON), chromium oxyfluoride (CrFO), silicon oxynitride (SiON), molybdenum silicon oxynitride (MoSiON), and titanium oxynitride (TiON) are used as the transmittance adjustment layer. Chromium (Cr), chromium nitride (CrN), tantalum (Ta), and titanium (Ti) are used. As a specific combination of materials when the translucent phase shift film is composed of two layers, an example is a combination in which the phase adjustment layer is chromium oxynitride (CrON), the transmittance adjustment layer is chromium nitride (CrN), and the phase adjustment layer is oxyfluoride. Chromium (CrFO), the transmittance adjustment layer is a combination of chromium nitride (CrN), the phase adjustment layer is silicon molybdenum oxynitride (MoSiON), and the transmittance adjustment layer is a silicon molybdenum oxynitride (MoSiON) with a smaller oxygen ratio than the phase adjustment layer ) combination.

In the present invention, a single-layer chromium oxynitride (CrON) film can be specifically exemplified.

4.Transparent substrate The transparent substrate used in the present invention is not particularly limited as long as it can form the above-mentioned light-shielding main portion and light-shielding auxiliary pattern. The transparent substrate used in ordinary photomasks can be used. As the transparent substrate, for example, optically polished low-expansion glass such as borosilicate glass and aluminoborosilicate glass can be used; quartz glass, synthetic quartz glass, Pyrex (registered trademark) glass, soda-lime glass, white sapphire, etc. can be used. transparent rigid materials, or flexible transparent flexible materials such as transparent resin films and optical resin films. Among them, quartz glass is a material with a small thermal expansion coefficient and has excellent dimensional stability and characteristics during high-temperature heat treatment.

5. Mask for proximity exposure Next, the photomask for proximity exposure in this invention is demonstrated. The photomask for proximity exposure of the present invention is not particularly limited as long as the light-shielding film including the light-shielding main part and the light-shielding auxiliary pattern is formed on the transparent substrate.

The photomask for proximity exposure in the present invention usually has a light-shielding main part formed with one or a plurality of openings, and one or a plurality of the light-shielding auxiliary patterns arranged inside the opening. In the present invention, the plurality of openings formed in the light-shielding main portion of the proximity exposure mask may have the same shape and size, or may be different. In addition, the light-shielding auxiliary patterns arranged inside each opening may be the same or different in shape, size, and arrangement position in the opening.

Furthermore, in the present invention, at least one of the plurality of openings formed in the light-shielding main portion of the proximity exposure mask only needs to be provided with the above-mentioned light-shielding auxiliary pattern on the inside, or may have no light-shielding auxiliary pattern arranged on the inside. The opening of the pattern.

In response to recent trends in the development of high-definition and thin LCD panels and the addition of touch panel functions, the requirements for miniaturization and improved durability of spacers have increased. For example, the first photosensitive spacer and low-voltage spacers have been developed. A color filter, etc., to the second photosensitive spacer (which is thinner) to the first photosensitive spacer.

The photomask for proximity exposure in the present invention includes multiple combinations of openings and auxiliary light-shielding patterns, or, in addition to openings provided with auxiliary light-shielding patterns, also includes openings without auxiliary light-shielding patterns, whereby it can be used One mask forms columnar patterns (for example, photosensitive spacers) of different heights (thickness) or different sizes (diameter).

The photomask for proximity exposure of the present invention is not particularly limited to the exposure light source. The exposure light source can be, for example, a mercury lamp, and the exposure light can be j line (313 nm), i line (365 nm), h line (405 nm), g Any one of the lines (436 nm) or mixed wavelengths of light containing these wavelength ranges. When the exposure light of the above mixed wavelength is used, there is an advantage that the exposure energy imparted to the photosensitive resin layer in the transparent area can be increased and the exposure time can be shortened.

Moreover, the photomask for proximity exposure of this invention is suitable for the case where a negative resist is used to form the fine columnar pattern corresponding to the said opening part. Specifically, it is particularly useful when forming a photosensitive spacer of a color filter for a liquid crystal display device as described below. However, the present invention is not limited to this case, and may be used when a positive resist is used to form micropores corresponding to the openings.

B. Manufacturing method of color filter The manufacturing method of the color filter in the present invention is characterized in that: the color filter is provided with a black matrix, colored pixels and photosensitive spacers on a transparent substrate for color filters, and the manufacturing method of the color filter has a photosensitive spacer. The step of forming a spacer is a step of forming a photosensitive spacer by using the above-mentioned photomask for proximity exposure to form a columnar pattern including a columnar pattern corresponding to the above-mentioned opening in the above-mentioned light-shielding main part.

(1) Photo spacer forming step The photo spacer forming step in the present invention is a step of using the above-mentioned proximity exposure mask to form a photo spacer including a columnar pattern corresponding to the above-mentioned opening. Specifically, it may be a step of exposing and developing a photospacer-forming composition containing a negative photosensitive resin to form a photospacer including a columnar pattern formed in the same pattern as the openings.

As the composition for forming a photosensitive spacer used in this step, it is preferable that the area other than the transfer pattern (columnar pattern) is not easily sensitive to light, and it is preferable that the resolution threshold of the resist is the light that has passed through the phase shift film. intensity above.

The shape of the above-mentioned columnar pattern formed by this step is usually cylindrical or polygonal columnar. In addition, the base size (diameter) of the columnar pattern is, for example, 17 μm or less, and preferably 12 μm or less. On the other hand, it is preferably 5 μm or more, and particularly preferably 8 μm or more. As a specific range, the range is preferably from 5 μm to 17 μm, and particularly preferably from 8 μm to 12 μm.

In addition, the height of the columnar pattern formed in this step is usually 1.0 μm or more, and preferably 1.5 μm or more. On the other hand, it is usually 4.0 μm or less, and preferably 3.0 μm or less. As a specific range, it is usually about 1.0 μm or more and 4.0 μm or less, and preferably it is about 1.5 μm or more and 3.0 μm or less.

Furthermore, by using the proximity exposure mask of the present invention, a color filter including a first photosensitive spacer and a second photosensitive spacer lower than the first photosensitive spacer can be manufactured. In this case, the transfer pattern corresponding to the opening of the proximity exposure mask of the present invention may be either the first photosensitive spacer or the second photosensitive spacer.

Specifically, in this step, a negative resist composition for forming a photosensitive spacer can be coated on a transparent substrate for a color filter on which a black matrix and colored pixels are formed, and dried, and exposed through a mask. Partially hardened, developed using an alkaline developer to pattern the photosensitive spacers.

The photosensitive spacer is preferably formed above the non-display area, that is, the black matrix.

(2)Other steps The manufacturing method of the color filter according to this embodiment is not particularly limited as long as it includes the above-described photospacer forming step. For example, it may include a black matrix forming step of forming a black matrix, a colored layer forming step of forming a colored layer, and Necessary steps include forming a transparent electrode layer on the above-mentioned colored layer and forming a transparent electrode layer on the colored layer. These steps may be the same as those in ordinary color filter manufacturing methods.

In addition, the present invention is not limited to the above-described embodiment. The above-mentioned embodiments are examples, and anything that has substantially the same structure as the technical ideas described in the patent application scope of the present invention and achieves the same effects is included in the technical scope of the present invention. [Example]

Examples and comparative examples are shown below to explain the present invention in more detail.

(Comparative Example 1, Example 1) For the masks of Comparative Example 1 and Example 1 set as follows, the difference in bottom size under the same light intensity was obtained through simulation. The binary mask shown in Figure 7(A) was used as the photomask of Comparative Example 1. This binary mask has an opening with a diameter of 13 μm formed on a transparent substrate made of quartz glass and has an OD value greater than 3. The shading film. The photomask shown in FIG. 7(B) is used as the photomask of Example 1. This photomask is formed with a light-shielding main part 31 and an annular shape with a width of 2 μm and an inner diameter of 2 μm on a transparent substrate made of quartz glass. The light-shielding auxiliary pattern 32 is composed of a 180-degree phase shift film with a transmittance of 5.2% and has an opening with a diameter of 14 μm. The light-shielding auxiliary pattern 32 is arranged inside the opening.

Through simulation, it was obtained that when the exposure gap G is set to 200 μm, the maximum light intensity is approximately the same as that of Comparative Example 1: 1.87 and Example 1: 1.83 when approaching exposure is performed on the exposed object. light intensity distribution. The results are shown in Figure 7(C). In addition, the above maximum light intensity is the value when the incident light intensity is set to 1, and other transfer conditions are set to: collimation half angle: 0.7 degrees, exposure wavelength: j line (313 nm), i line (365 nm) , h-line (405 nm) and g-line (436 nm) mixed wavelength light.

Based on Figure 7(C), the bottom dimension (Y in Figure 7) of the transfer pattern obtained in Comparative Example 1 was calculated to be 12.61 μm, and the bottom dimension (Y in Figure 7) of the transfer pattern obtained in Example 1 was calculated. X) is 9.86 μm (Figure 10(A)). Furthermore, the slope value was 0.093 in Comparative Example 1 and 0.170 in Example 1. It was confirmed that the size of the transfer pattern in Example 1 was reduced and the taper angle was also increased.

(Comparative Example 2, Example 2) For the masks of Comparative Example 2 and Example 2 set as follows, the difference in the taper angle when the bottom size is the same was obtained through simulation. The binary mask shown in FIG. 8(A) was used as the photomask of Comparative Example 2. This binary mask has a light-shielding film (OD) with an opening of 8 μm in diameter on a transparent substrate made of quartz glass. Value: greater than 3). The photomask shown in FIG. 8(B) is used as the photomask of Example 2. This photomask is formed with a light-shielding main part 31 on a transparent substrate made of quartz glass, a ring shape with a width of 1 μm and an inner diameter of 8 μm. The light-shielding auxiliary pattern 32a and the annular light-shielding auxiliary pattern 32b with a width of 1 μm and an inner diameter of 2 μm are formed. The light-shielding main part 31 is composed of a 180-degree phase shift film with a transmittance of 5.2% and is formed with an opening of 14 μm in diameter. , the light-shielding auxiliary pattern 32a and the light-shielding auxiliary pattern 32b are arranged inside the opening.

Through simulation, an exposed object with an exposure gap G of 200 μm was obtained, and the bottom size of the obtained transfer pattern was approximately the same as that of Comparative Example 2: 9.38 μm and Example 2: 9.28 μm. The light intensity distribution formed on the exposed object during exposure. The results are shown in Figure 8(C). Furthermore, the transfer conditions are set to: collimation half angle: 0.7 degrees, exposure wavelength: the mixed wavelength of j line (313 nm), i line (365 nm), h line (405 nm) and g line (436 nm). Light.

According to FIG. 8(C) , the maximum light intensity obtained in Comparative Example 2 is 0.39, and the maximum light intensity obtained in Example 2 is 1.26. In addition, the slope value was 0.05 in Comparative Example 2 and 0.165 in Example 2, and it was confirmed that the taper angle also increased (Fig. 10(B)).

(Example 3) The photomask shown in FIG. 9(B) is used as the photomask of Example 3. This photomask is mounted on a transparent substrate made of quartz glass, and has a light-shielding main part 31 and a width of 1 μm and an inner An annular light-shielding auxiliary pattern 32 with a diameter of 13 μm. The light-shielding main part 31 is composed of a 180-degree phase shift film with a transmittance of 5.2% and is formed with an opening of 17 μm in diameter. The light-shielding auxiliary pattern 32 is arranged in the opening. inside. Through simulation, the light intensity distribution during proximity exposure was obtained with an exposure gap G of 200 μm and a transfer pattern size of 13.2 μm. The maximum light intensity in Example 3 is 2.011. The transfer conditions are set to: collimation half angle: 0.7 degrees, exposure wavelength: mixed wavelength light of j line (313 nm), i line (365 nm), h line (405 nm) and g line (436 nm). Furthermore, the exposure gap was changed to 180 μm, and the transfer pattern size when proximity exposure was performed under the above transfer conditions was obtained through simulation. The change rate of the transfer pattern size CD (ΔCD/ΔGap) due to the change of the exposure gap from 200 μm to 180 μm was calculated from the following formula to be 0.003. ΔCD/ΔGap=(CD ₂₀₀ - CD ₁₈₀ )/(200 μm - 180 μm) In the formula, CD ₂₀₀ is the transfer pattern size when the exposure gap is 200 μm, and CD ₁₈₀ is the transfer pattern size when the exposure gap is 180 μm.

(Comparative example 3) The binary mask shown in Figure 9(A) was used as the photomask of Comparative Example 3. The binary mask was formed on a transparent substrate made of quartz glass and had an opening with a diameter of 14 μm. The OD value was greater than 3. Light-shielding film. For the photomask of Comparative Example 3, it was determined through simulation that the exposure gap G was set to 200 μm and the bottom dimension of the transfer pattern was 13.3 μm, which was approximately the same as that of Example 3. Light intensity distribution during proximity exposure under transfer conditions. The results are shown in Figure 9(C). In Comparative Example 3, the maximum light intensity when the exposure gap is 200 μm is 2.128. In addition, the light intensity distribution obtained by simulation when only the exposure gap was changed to 180 μm is shown in Fig. 9(C) . In addition, the change rate of the transfer pattern size CD (ΔCD/ΔGap) caused by changing the exposure gap from 200 μm to 180 μm was calculated by the above formula. ΔCD/ΔGap is 0.027. It was confirmed that in Example 3, compared to Comparative Example 3, the change in the size of the transfer pattern due to the change in the exposure gap was smaller (Fig. 10(C)).

(Example 4) The proximity exposure mask having two opening patterns for the first photosensitive spacer and the second photosensitive spacer shown in Figures 11 (A) and (B) was formed on the exposed body through simulation. light intensity distribution. The results are shown in Figure 11(C). Furthermore, the light-shielding film 3 is a 180-degree phase shift film with a transmittance of 5.2%. The transfer conditions are set to: collimation half angle: 0.7 degrees, exposure wavelength: j line (313 nm), i line (365 nm), h line (405 nm) and g-line (436 nm) mixed wavelength light, exposure gap: 200 μm. The opening pattern in Figure 11(A) is the same as the opening pattern in Figure 11(B) in terms of bottom size 11.8 μm, but the maximum light intensity is different ((A): 2.62, (B): 0.88). Based on the above, it can be confirmed that columnar photo spacers (Photo Spacers) with different heights and sizes can be formed from one mask by combining different opening patterns.

Furthermore, the present invention provides the following inventions, for example.

[1] A photomask for proximity exposure, which is a photomask for proximity exposure, and Having a transparent substrate and a light-shielding film disposed on the transparent substrate, The light-shielding film has: a light-shielding main part formed with a substantially polygonal or generally circular opening; and a light-shielding auxiliary pattern disposed inside the opening of the light-shielding main part and formed at a distance from the light-shielding main part. ; The above-mentioned light-shielding film is a phase-shift film with a phase shift of 180 degrees ± 45 degrees relative to the exposed light, and a transmittance of the exposed light of 1% or more and 10% or less. [2] The proximity exposure mask as [1], wherein the proximity exposure mask is based on the peak of the light intensity distribution of the light passing through it relative to a reference mask aiming to form a transfer pattern with the same bottom size. In order to increase the rising angle, the above-mentioned light-shielding auxiliary pattern is arranged. [3] A photomask for proximity exposure such as [1] or [2], in which The diameter of the opening is 10 μm or more and 20 μm or less. [4] A photomask for proximity exposure according to any one of [1] to [3], wherein The above-mentioned exposure light is a mixed wavelength light of j line (313 nm), i line (365 nm), h line (405 nm) and g line (436 nm). [5] A method of manufacturing a color filter, characterized in that: the color filter is provided with a black matrix, colored pixels, and photosensitive spacers on a transparent substrate for color filters, The manufacturing method of the above-mentioned color filter has a step of forming a photosensitive spacer. The photospacer forming step uses a proximity exposure mask as described in any one of [1] to [4] to form a photospacer including the above-mentioned light-shielding main part. A photosensitive spacer with a columnar pattern corresponding to the above-mentioned opening.

1: Mask for proximity exposure 2:Transparent substrate 3:Light-shielding film 31: Main part of shading 32: Blackout auxiliary pattern 32a: 1st shading auxiliary pattern 32b: 2nd shading auxiliary pattern 41:Outside transparent area 42: Inner transparent area 43: Inner transparent area 52:Substrate 53:Light of Exposure A:Diameter B:Width C:Inner diameter L1:Light L2:Light O: opening P:point Q:Point r: distance S: point X: Dimensions under the transfer pattern of Example 1 Y: Bottom size of the transfer pattern of Comparative Example 1 δ: angle

1 (A) and (B) are a plan view and a schematic cross-sectional view showing an example of the photomask for proximity exposure of the present invention. 2 (A) and (B) are diagrams illustrating the light amplitude distribution and light intensity distribution on the imaging surface of the mask when a phase shift film is used as a light-shielding film. Figure 3 is a diagram used to illustrate Fresnel diffraction. FIG. 4 is a plan view showing an example of the photomask for proximity exposure according to the present invention. FIG. 5 is a simulation result showing the relationship between the bottom size and the slope value of the transfer pattern (columnar pattern) in the proximity exposure mask of the present invention and the reference mask. FIG. 6 is a plan view showing an example of the photomask for proximity exposure according to the present invention. 7 (A) to (C) are top views of the proximity exposure masks of Example 1 and Comparative Example 1 and simulation results thereof. 8(A) to (C) are top views of the proximity exposure masks of Example 2 and Comparative Example 2 and simulation results thereof. 9(A) to 9(C) are top views of the proximity exposure masks of Example 3 and Comparative Example 3 and simulation results thereof. Figures 10 (A) to (C) show the results of Examples 1 to 3 and Comparative Examples 1 to 3. 11 (A) to (C) are top views of the proximity exposure mask of Example 4 and simulation results thereof.

1: Mask for proximity exposure

2:Transparent substrate

3:Light-shielding film

31: Main part of shading

32: Blackout auxiliary pattern

41:Outside transparent area

42: Inner transparent area

O: opening

Claims (5)

A photomask for proximity exposure, which is a photomask for proximity exposure, and Having a transparent substrate and a light-shielding film disposed on the transparent substrate, The light-shielding film has: a light-shielding main part formed with a substantially polygonal or generally circular opening; and a light-shielding auxiliary pattern disposed inside the opening of the light-shielding main part and formed at a distance from the light-shielding main part. ; The above-mentioned light-shielding film is a phase-shift film with a phase shift of 180 degrees ± 45 degrees relative to the exposed light, and a transmittance of the exposed light of 1% or more and 10% or less. The photomask for proximity exposure as claimed in claim 1, wherein The above-mentioned mask for proximity exposure has the above-mentioned light-shielding auxiliary pattern arranged so that the rising angle of the peak of the light intensity distribution of the light passing through becomes larger with respect to a reference mask aiming at forming a transfer pattern with the same bottom size. . The photomask for proximity exposure as claimed in claim 1, wherein The diameter of the opening is 10 μm or more and 20 μm or less. The photomask for proximity exposure as claimed in claim 1, wherein The above-mentioned exposure light is a mixed wavelength light of j line (313 nm), i line (365 nm), h line (405 nm) and g line (436 nm). A method of manufacturing a color filter, characterized in that: the color filter is provided with a black matrix, colored pixels, and photosensitive spacers on a transparent substrate for color filters, The manufacturing method of the above-mentioned color filter has a step of forming a photosensitive spacer. The photosensitive spacer forming step uses a proximity exposure mask according to any one of claims 1 to 4 to form a photosensitive spacer including the light-shielding main part. The photosensitive spacer of the columnar pattern corresponding to the above-mentioned opening.