Method for manufacturing a display device

Abstract

This invention provides a transfer mask that enables PDL (Printed Directive Printing) with a small tilt angle around the opening. [Solution] A transfer mask comprising a transfer pattern on a translucent substrate including a translucent portion, a first translucent portion, and a second translucent portion, wherein the translucent portion has a hole shape in which the translucent substrate is exposed, the first translucent portion is provided in an annular manner along the outer circumference of the translucent portion, the second translucent portion is provided in contact with the outer circumference of the first translucent portion, the transmittance T1 of the first translucent portion with respect to exposure light is higher than the transmittance T2 of the second translucent portion with respect to exposure light, the absolute value of the phase difference between the exposure light transmitted through the first translucent portion and the exposure light transmitted through the translucent portion is 90 degrees or less, the absolute value of the phase difference between the exposure light transmitted through the second translucent portion and the exposure light transmitted through the second translucent portion is 90 degrees or less.

Description

Technical Field

[0001] The present invention relates to a transfer mask and a method for manufacturing a display device.

Background Art

[0002] In Patent Document 1, in a photomask for manufacturing a display device having a transfer pattern including a light-transmitting portion, a light-shielding portion, and a semi-light-transmitting portion in order to form resist patterns having a plurality of different remaining film values on a transfer target by exposure, the light-transmitting portion is formed by exposing a transparent substrate, and the light-shielding portion includes a complete light-shielding portion in which at least a light-shielding film is formed on the transparent substrate, and a rim portion having a width γ formed in contact with the outer edge of the complete light-shielding portion and having a semi-light-transmitting rim-forming film formed on the transparent substrate. The semi-light-transmitting portion is sandwiched between the light-shielding portions, and the transparent substrate is exposed with a predetermined width α. The width α is set such that the exposure light transmittance of the semi-light-transmitting portion is smaller than the exposure light transmittance of the light-transmitting portion. The rim-forming film has a transmittance Tr of 5 to 60 (%) with respect to light having a representative wavelength of exposure light and a phase shift amount with respect to light having the representative wavelength of 90 degrees or less. A photomask is described.

[0003] Further, Patent Document 2 describes an organic EL display device in which pixels are arranged in a matrix in a display area, an organic EL layer arranged in each pixel, a separation layer surrounding the edge of the organic EL layer and arranged between adjacent pixels, a resin layer that seals the organic EL layer by covering the entire surface of the display area, and a frame-shaped bank surrounding the edge of the resin layer. An organic EL display device is described, characterized in that the taper angle of the separation layer and the taper angle of the frame-shaped bank are different.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

[0005] Many products using organic electroluminescent (OLED) displays have been developed for display devices with thin displays, such as smartphones, tablets, and televisions. Generally, OLED displays have an insulating layer called a pixel-defining layer (PDL) formed to separate the pixels of the light-emitting element.

[0006] One embodiment of the present invention aims to provide a transfer mask that can achieve PDL with a small tilt angle around the opening. [Means for solving the problem]

[0007] A first aspect of the present invention is: A transfer mask comprising a transfer pattern on a translucent substrate, including a translucent portion, a first translucent portion, and a second translucent portion, The light-transmitting portion has a hole shape in which the light-transmitting substrate is exposed. The first transmissive portion is provided in an annular shape along the outer circumference of the light-transmitting portion, The second permeable portion is provided in contact with the outer circumference of the first permeable portion, The transmittance T1 of the first transmission portion to the exposure light is higher than the transmittance T2 of the second transmission portion to the exposure light. The absolute value of the phase difference between the exposure light transmitted through the first transmission portion and the exposure light transmitted through the light-transmitting portion is 90 degrees or less. The absolute value of the phase difference between the exposure light transmitted through the second transmissive portion and the exposure light transmitted through the light-transmitting portion is 90 degrees or less. The transfer mask is characterized in that the absolute value of the phase difference between the exposure light transmitted through the first transparent portion and the exposure light transmitted through the second transparent portion is 90 degrees or less.

[0008] A second aspect of the present invention is: The transfer mask according to the first embodiment is characterized in that the width D of the first transparent portion is 1.5 μm or more.

[0009] A third aspect of the present invention is: The transfer mask according to the first embodiment is characterized in that the difference ΔT between the transmittance T1 and the transmittance T2 is 10% or more.

[0010] A fourth aspect of the present invention is: The width D of the first transparent portion and the difference ΔT between the transmittance T1 and the transmittance T2 are, The transfer mask described in the first embodiment is characterized by satisfying the relationship D≧-3.14×ΔT / 100+2.32.

[0011] A fifth aspect of the present invention is: The transfer mask according to the first embodiment is characterized in that the transmittance T1 is 20% or more.

[0012] A sixth aspect of the present invention is: The transfer mask according to the first embodiment is characterized in that the transmittance T2 is 10% or more.

[0013] A seventh aspect of the present invention is: The transfer mask according to the first embodiment is characterized in that the exposure light includes light with a wavelength of 313 nm to 436 nm.

[0014] An eighth aspect of the present invention is: The transfer mask according to the first embodiment is characterized by further having a light-shielding portion provided adjacent to the second transparent portion.

[0015] A ninth aspect of the present invention is: The first transparent portion consists of a first semi-permeable film formed on the light-transmitting substrate. The transfer mask according to the first embodiment is characterized in that the second transparent portion is formed by laminating the first semi-permeable film and the second semi-permeable film on the light-transmitting substrate.

[0016] A tenth aspect of the present invention is: The transfer mask according to the ninth aspect is characterized in that the first semi-transmissive film and the second semi-transmissive film are made of materials having etching selectivity with respect to each other.

[0017] The eleventh aspect of the present invention is further comprising a light-shielding portion provided adjacent to the second transmissive portion, The transfer mask according to the ninth aspect is characterized in that the light-shielding portion is formed by laminating a light-shielding film having light-shielding properties, the first semi-transmissive film, and the second semi-transmissive film on the light-transmissive substrate.

[0018] The twelfth aspect of the present invention is The transfer mask according to the eleventh aspect is characterized in that the second semi-transmissive film and the light-shielding film are made of materials having etching selectivity with respect to each other.

[0019] The thirteenth aspect of the present invention is a step of preparing the transfer mask according to any one of the first to twelfth aspects, a step of forming a photosensitive resin film that is sensitive to the exposure light on the substrate, a step of irradiating the photosensitive resin film with the exposure light transmitted through the transfer mask using an exposure apparatus to perform exposure transfer of the transfer pattern, a step of performing development processing on the photosensitive resin film after the exposure transfer, A method for manufacturing a display device, characterized by comprising:

[0020] The fourteenth aspect of the present invention is In the step of exposure transfer, the transfer pattern is exposure-transferred so that an inclined portion having an inclined angle of 30 degrees or less in cross section is formed around the opening of the photosensitive resin film after the development process. The method for manufacturing a display device according to the thirteenth aspect.

Advantages of the Invention

[0021] According to one embodiment of the present invention, it is possible to provide a transfer mask that can achieve PDL with a small tilt angle around the opening. [Brief explanation of the drawing]

[0022] [Figure 1] Figure 1 is a schematic plan view showing a transfer mask 1 according to a first embodiment of the present invention. [Figure 2] Figure 2 is a schematic cross-sectional view of line AA of the transfer mask 1 shown in Figure 1. [Figure 3] Figures 3(a) to 3(e) are schematic diagrams illustrating a method for manufacturing a transfer mask 1 according to a first embodiment of the present invention. [Figure 4] Figure 4 is a schematic cross-sectional view of a transfer mask 1 according to Modification 1 of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view of a transfer mask 1 according to a modified example 2 of the present invention. [Figure 6] Figure 6 is a graph showing the relationship between width D and inclination angle θ according to Embodiment 1 of the present invention. [Figure 7] Figure 7 is a graph showing the relationship between width D and inclination angle θ according to Embodiment 2 of the present invention. [Figure 8] Figure 8 is a graph showing selected conditions from Examples 1 and 2 of the present invention. [Figure 9] Figure 9 is a schematic cross-sectional view of the PDL of an organic EL display device. [Modes for carrying out the invention]

[0023] <Insights gained by the inventor> First, the inventors' findings will be explained. Figure 9 is a schematic cross-sectional view of a PDL of an organic EL display device. The PDL is made of, for example, photosensitive polyimide and, as shown in Figure 9, comprises an opening 200 for forming an emissive layer, an inclined portion 201 located around the opening 200, a column portion 202 for supporting the mask when forming the emissive layer, and a flat portion 203 at an intermediate height between the opening 200 and the column portion 202.

[0024] After forming the light-emitting layer in the opening 200 of the PDL, it is necessary to seal the light-emitting layer with a sealing material such as polyimide in order to maintain the light-emitting efficiency. At this time, the manufacturing yield can be improved by improving the wetting spread and flatness of the sealing material. Therefore, it is preferable that the inclination angle θ of the inclined portion 201 of the PDL be small. Specifically, the inclination angle θ is preferably 30 degrees or less, and more preferably 20 degrees or less. Furthermore, the lower limit of the inclination angle θ is not particularly limited, but it is preferable that it be 10 degrees or more from the viewpoint of making it easier to secure a sufficient thickness of the flat portion 203 (for example, 0.8 μm or more and 1.5 μm or less).

[0025] Next, one embodiment of the present invention will be described below with reference to the drawings. However, the present invention is not limited to these examples and is intended to include all modifications within the meaning and scope equivalent to the claims, as shown in the claims.

[0026] <First Embodiment of the Invention> (1) Configuration of the transfer mask 1 First, the configuration of the transfer mask 1 of this embodiment will be described. Figure 1 is a schematic plan view of the transfer mask 1 of this embodiment, and Figure 2 is a schematic cross-sectional view of line AA in Figure 1. As shown in Figure 1, the transfer mask 1 of this embodiment has a transfer pattern on a translucent substrate 100 that includes a translucent portion 10, a first translucent portion 20, a second translucent portion 30, and a light-shielding portion 40. The transfer mask 1 of this embodiment can be used, for example, to form a PDL of an organic EL display device. In particular, the transfer mask 1 of this embodiment can form the openings 200 and column portions 202 of the PDL simultaneously with a single mask.

[0027] The light-transmitting portion 10 is a hole-shaped region where the translucent substrate 100 is exposed. In Figure 1, as an example, the light-transmitting portion 10 is shown as a rectangular hole, but it may also be a circular or polygonal hole shape other than a square. The light-transmitting portion 10 is the region corresponding to the opening 200 of the PDL when forming the PDL, and its size is not particularly limited and can be determined according to the design of the display device to be manufactured. In this specification, the transmittance to the exposure light (hereinafter also simply referred to as exposure light) used to expose the transfer mask 1 is defined with the light-transmitting portion 10 (i.e., the translucent substrate 100) as the reference (100%).

[0028] As shown in Figure 1, the first transmissive portion 20 is an annular region provided along the outer circumference of the light-transmitting portion 10. The first transmissive portion 20 is configured to partially transmit exposure light. The first transmissive portion 20 is a region necessary to reduce the inclination angle θ of the inclined portion 201 located around the opening 200 of the PDL when forming the PDL. It is preferable that the first transmissive portion 20 surrounds the entire outer circumference of the light-transmitting portion 10, but as long as the effects of the invention are obtained, the first transmissive portion 20 may have a shape in which a part of the annular region is missing (the missing part becomes part of the second transmissive portion 30). Furthermore, the first transmissive portion 20 is considered to be provided in an annular shape even if a part is missing, as long as it surrounds 80% or more of the outer circumference of the light-transmitting portion 10. It is preferable that the first transmissive portion 20 surrounds 90% or more of the outer circumference of the light-transmitting portion 10, and it is more preferable that it surrounds 100% (the entire circumference).

[0029] As shown in Figure 1, the second transparent portion 30 is a region provided so as to be in contact with the outer circumference of the first transparent portion 20. The second transparent portion 30 is the region corresponding to the flat portion 203 of the PDL when forming the PDL. Also, as shown in Figure 1, the second transparent portion 30 is the region with the largest area among the light-transmitting portion 10, the first transparent portion 20, the second transparent portion 30, and the light-shielding portion 40.

[0030] As shown in Figure 1, the light-shielding portion 40 is a region provided adjacent to the second transmissive portion 30. The light-shielding portion 40 is configured such that exposure light is substantially blocked (for example, the optical density OD with respect to exposure light is greater than 2.0, preferably OD is 2.5 or higher, more preferably OD is 3.0 or higher), and is the region corresponding to the column portion 202 of the PDL when forming the PDL.

[0031] In the transfer mask 1, the transmittance T1 of the first transparent portion 20 is higher than the transmittance T2 of the second transparent portion 30. This makes it possible to reduce the inclination angle θ of the inclined portion 201 located around the opening 200 when forming the PDL.

[0032] Preferably, the transfer mask 1 is designed in such a way that the phenomenon of attenuation of the amount of exposure light due to the phase difference between the exposure light passing through the light-transmitting portion 10, the first light-transmitting portion 20, and the second light-transmitting portion 30 is suppressed. Specifically, it is preferable that the absolute value of the phase difference between the exposure light that has passed through the first light-transmitting portion 20 and the exposure light that has passed through the light-transmitting portion 10 is 90 degrees or less, the absolute value of the phase difference between the exposure light that has passed through the second light-transmitting portion 30 and the exposure light that has passed through the light-transmitting portion 10 is 90 degrees or less, and the absolute value of the phase difference between the exposure light that has passed through the first light-transmitting portion 20 and the exposure light that has passed through the second light-transmitting portion 30 is 90 degrees or less. If the phase difference between the exposure light that has passed through the light-transmitting portion 10, the first light-transmitting portion 20, and the second light-transmitting portion 30 of the transfer mask 1 exceeds the above ranges, the inclination angle θ of the inclined portion 201 of the PDL may become large. In contrast, by keeping the phase difference between the exposure light transmitted through the light-transmitting portion 10, the first light-transmitting portion 20, and the second light-transmitting portion 30 of the transfer mask 1 within the above ranges, it becomes possible to reduce the inclination angle θ of the inclined portion 201. The absolute value of the phase difference between the exposure light transmitted through the first light-transmitting portion 20 and the exposure light transmitted through the light-transmitting portion 10 is more preferably 80 degrees or less, and even more preferably 60 degrees or less. The absolute value of the phase difference between the exposure light transmitted through the second light-transmitting portion 30 and the exposure light transmitted through the light-transmitting portion 10 is more preferably 80 degrees or less, and even more preferably 60 degrees or less. The absolute value of the phase difference between the exposure light transmitted through the first light-transmitting portion 20 and the exposure light transmitted through the second light-transmitting portion 30 is more preferably 80 degrees or less, and even more preferably 60 degrees or less.

[0033] The width D of the first transparent portion 20 (i.e., the distance between the boundary between the light-transmitting portion 10 and the first transparent portion 20, and the boundary between the first transparent portion 20 and the second transparent portion 30) is preferably, for example, 1.5 μm or more. If the width D is less than 1.5 μm, it may not be possible to sufficiently reduce the inclination angle θ of the inclined portion 201. In contrast, by setting the width D to 1.5 μm or more, the inclination angle θ of the inclined portion 201 can be sufficiently reduced. The width D is more preferably greater than 1.5 μm, and even more preferably 1.7 μm or more. On the other hand, the width D is preferably 10 μm or less. If the width D exceeds 10 μm, the first transparent portion 20 and the light-shielding portion 40 may come into contact or be too close together. In contrast, by setting the width D to 10 μm or less, a sufficient distance can be secured between the first transparent portion 20 and the light-shielding portion 40. The width D is more preferably 7 μm or less, and even more preferably 5 μm or less. If the width D exceeds 5 μm, the effect of reducing the inclination angle θ of the inclined portion 201 may saturate.

[0034] The width D of the first translucent portion 20 is preferably a substantially constant value (for example, within the range of ±5% of the average value). For example, if the width D is different depending on the direction from the center of the light-transmitting portion 10, the inclination angle θ of the inclined portion 201 may differ depending on the direction when forming the PDL. In contrast, by making the width D a substantially constant value, the inclination angle θ of the inclined portion 201 can be made a substantially constant value when forming the PDL. This makes it possible to further improve the yield when manufacturing the display device.

[0035] The difference ΔT (=T1-T2) between the transmittance T1 of the first transparent section 20 and the transmittance T2 of the second transparent section 30 is preferably 10% or more. If the transmittance difference ΔT is less than 10%, it may not be possible to sufficiently reduce the inclination angle θ of the inclined section 201. In contrast, by setting the transmittance difference ΔT to 10% or more, the inclination angle θ of the inclined section 201 can be sufficiently reduced. On the other hand, it is preferable that the transmittance difference ΔT be 30% or less, and more preferably 25% or less. If the transmittance difference ΔT exceeds 25%, it may become difficult to obtain the effect of reducing the inclination angle θ of the inclined section 201. In contrast, by setting the transmittance difference ΔT to 25% or less, the inclination angle θ of the inclined section 201 can be sufficiently reduced.

[0036] The width D [μm] of the first transparent portion 20 and the difference ΔT [%] between the transmittance T1 [%] and the transmittance T2 [%] preferably satisfy the relationship D ≥ -3.14 × ΔT / 100 + 2.32. This allows the inclination angle θ of the inclined portion 201 to be made smaller (for example, 30 degrees or less). The above relationship will be explained in detail in the embodiments described later.

[0037] The transmittance T1 of the first transparent portion 20 is preferably 20% or more, more preferably 30% or more, and even more preferably greater than 30%. On the other hand, the transmittance T1 is preferably 60% or less, and more preferably 50% or less. The transmittance T2 of the second transparent portion 30 is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. On the other hand, the transmittance T2 is preferably 40% or less, and more preferably 30% or less.

[0038] Exposure light refers to the light emitted by a light source provided in an exposure apparatus for manufacturing display devices. In this embodiment, the exposure light includes, for example, light with a wavelength of 313 nm to 436 nm. As the exposure light, single-wavelength light (for example, the i-line with a wavelength of 365 nm) may be used, or broad-wavelength light containing multiple wavelengths may be used. In this specification, transmittance and phase difference shall be given for the wavelength of the exposure light if it consists of a single wavelength, and for any wavelength (representative wavelength) included in the wavelength range of 313 nm to 436 nm if broad-wavelength light is used.

[0039] As shown in Figure 2, the first transparent portion 20 preferably consists of, for example, a first semi-permeable film 101 formed on a translucent substrate 100, and the second transparent portion 30 preferably consists of, for example, a first semi-permeable film 101 and a second semi-permeable film 102 laminated on a translucent substrate 100. In particular, it is more preferable that the second transparent portion 30 consists of a second semi-permeable film 102 formed on a translucent substrate 100, and a first semi-permeable film 101 formed on a second semi-permeable film 102. With this configuration, the transmittance T1 of the first transparent portion 20 is equal to the transmittance HT1 of the first semi-permeable film 101. On the other hand, the transmittance T2 of the second transparent portion 30 is the transmittance of the laminated structure of the first semi-permeable film 101 and the second semi-permeable film 102. The transmittance HT2 of the second semipermeable film 102 must be optically designed based on the transmittance T2 of the second transparent portion 30 and the transmittance HT1 of the first semipermeable film 101.

[0040] The film thickness d1 of the first semipermeable film 101 is preferably 5 nm or more, and more preferably 10 nm or more. Furthermore, the film thickness d1 is preferably 80 nm or less, and more preferably 60 nm or less. The film thickness d2 of the second semipermeable film 102 is preferably 3 nm or more, and more preferably 5 nm or more. Furthermore, the film thickness d2 is preferably 50 nm or less, and more preferably 40 nm or less.

[0041] The first semipermeable membrane 101 and the second semipermeable membrane 102 may be formed from chromium (Cr), or a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C) (chromium-based material). Examples of this chromium-based material include Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF. On the other hand, the first semipermeable membrane 101 and the second semipermeable membrane 102 may be formed from a material consisting of a metal and silicon, or a material containing a metal and silicon with at least one of oxygen (O), nitrogen (N), and carbon (C) (metal silicide-based material). Suitable metals for the metal silicide include transition metals such as molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), and zirconium (Zr). In metal silicide materials, the ratio of the metal content [atomic percent] to the total metal and silicon content [atomic percent] (hereinafter referred to as the "M / [M+Si] ratio") is preferably 0.5 or less, more preferably 1 / 3 or less, and even more preferably 0.3 or less. On the other hand, the M / [M+Si] ratio is preferably 0.05 or more, and more preferably 0.1 or more.

[0042] Preferably, the first semipermeable film 101 and the second semipermeable film 102 are made of materials that have mutual etching selectivity. This configuration facilitates the manufacture of the transfer mask 1 as shown in Figure 2. For example, thin films of chromium-based materials and thin films of metal silicide-based materials have mutual etching selectivity. The above effect can be obtained by forming one of the first semipermeable film 101 and the second semipermeable film 102 with a chromium-based material and the other with a metal silicide-based material.

[0043] As shown in Figure 2, the light-shielding portion 40 is preferably formed by laminating a light-shielding film 103, a first semi-permeable film 101, and a second semi-permeable film 102 on a translucent substrate 100. In particular, it is preferable that the light-shielding portion 40 is formed such that the light-shielding film 103 is formed on the translucent substrate 100, the second semi-permeable film 102 is formed on the light-shielding film 103, and the first semi-permeable film 101 is formed on the second semi-permeable film 102. This configuration makes it easy to manufacture the transfer mask 1 as shown in Figure 2. The light-shielding portion 40 may be formed from a chromium-based material or a metal silicide-based material.

[0044] Preferably, the second semipermeable film 102 and the light-shielding film 103 are made of materials that have etching selectivity with respect to each other. This configuration makes it easy to manufacture the transfer mask 1 as shown in Figure 2. For example, the above effect can be obtained by forming one of the second semipermeable film 102 and the light-shielding film 103 with a chromium-based material and the other with a metal silicide-based material.

[0045] The translucent substrate 100 is transparent to exposure light. The translucent substrate 100 has a transmittance of 85% or more, preferably 90% or more, to exposure light, assuming no surface reflection loss. The translucent substrate 100 is made of a material containing silicon and oxygen, and can be made of glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda-lime glass, or low thermal expansion glass (SiO2-TiO2 glass, etc.). Translucent substrates 100 used in transfer masks for display devices are generally rectangular substrates, and the length of the short side of the translucent substrate is 300 mm or more.

[0046] (2) Method for manufacturing the transfer mask 1 Next, the method for manufacturing the transfer mask 1 of this embodiment will be explained with reference to Figures 3(a) to 3(e). The transfer mask 1 of this embodiment can be manufactured, for example, by the method described below.

[0047] First, a light-shielding film 103 is formed on the translucent substrate 100. Known methods (for example, sputtering) can be used for film formation.

[0048] After forming the light-shielding film 103 on the translucent substrate 100, the light-shielding film 103 is patterned to match the shape of the light-shielding portion 40, as shown in Figure 3(a). Patterning can be done using known methods (for example, by placing a resist film having the pattern of the light-shielding portion 40 on the light-shielding film 103, and performing wet etching or dry etching using the resist film as a mask to form the pattern of the light-shielding portion 40 on the light-shielding film 103).

[0049] After patterning the light-shielding film 103, a second semi-transparent film 102 is deposited on the light-transmitting substrate 100 and the light-shielding film 103, as shown in Figure 3(b). Known methods (for example, sputtering) can be used for film deposition.

[0050] Once the second semipermeable film 102 is formed, the second semipermeable film 102 is patterned to match the shapes of the first transparent portion 20 and the light-transmitting portion 10, as shown in Figure 3(c). Patterning can be performed using known methods (for example, by placing a resist film having the patterns of the first transparent portion 20 and the light-transmitting portion 10 on the second semipermeable film 102, and then performing wet etching or dry etching using the resist film as a mask to form the patterns of the first transparent portion 20 and the light-transmitting portion 10 on the second semipermeable film 102).

[0051] After patterning the second semi-permeable film 102, the first semi-permeable film 101 is deposited on the translucent substrate 100 and the second semi-permeable film 102, as shown in Figure 3(d). Known methods (for example, sputtering) can be used for film deposition.

[0052] Once the first semi-permeable film 101 is formed, the first semi-permeable film 101 is patterned to match the shape of the light-transmitting portion 10, as shown in Figure 3(e). Patterning can be done using known methods (for example, by placing a resist film having the pattern of the light-transmitting portion 10 on the first semi-permeable film 101, and then performing wet etching or dry etching using the resist film as a mask to form the pattern of the light-transmitting portion 10 on the first semi-permeable film 101).

[0053] The transfer mask 1 of this embodiment can be manufactured by the method described above. Additional films other than those described above may be formed, provided that they do not impair the effectiveness of the transfer mask 1.

[0054] (3) Method for manufacturing a display device The present invention is also applicable as a method for manufacturing display devices such as organic EL displays. The method for manufacturing a display device according to this embodiment is a method for manufacturing a display device that includes, for example, the steps of: preparing the transfer mask 1 according to this embodiment; forming a photosensitive resin film (for example, a thin film made of photosensitive polyimide) on a substrate that is sensitive to exposure light; irradiating the photosensitive resin film with exposure light transmitted through the transfer mask 1 using an exposure apparatus to expose and transfer a transfer pattern; and performing a development process on the exposed and transferred photosensitive resin film.

[0055] In the method for manufacturing the display device of this embodiment, in the step of exposing and transferring the transfer pattern, it is preferable to expose and transfer the transfer pattern such that an inclined portion 201 is formed around the opening 200 of the photosensitive resin film after development, with a cross-sectional inclination angle θ of 30 degrees or less (more preferably 20 degrees or less). As described above, the transfer mask 1 has a configuration for reducing the inclination angle θ of the inclined portion 201, so by appropriately selecting the exposure apparatus and exposure conditions, it is possible to make the inclination angle θ 30 degrees or less (or 20 degrees or less). This makes it possible to further improve the yield when manufacturing the display device.

[0056] (4) Modified form of the first embodiment The embodiments described above can be modified as necessary, as shown in the following examples. Below, only elements that differ from the embodiments described above will be described, and elements that are substantially the same as those described in the embodiments above will be denoted by the same reference numerals and their descriptions will be omitted.

[0057] (4-1) Modification 1 of the first embodiment Figure 4 is a schematic cross-sectional view of the transfer mask 1 of this modified example. The transfer mask 1 of this modified example, like the first embodiment described above, has a transfer pattern on a translucent substrate 100 and includes a translucent portion 10, a first translucent portion 20, a second translucent portion 30, and a light-shielding portion 40. Therefore, this modified transfer mask 1 can also reduce the inclination angle θ of the inclined portion 201 located around the opening 200 when forming the PDL.

[0058] As shown in Figure 4, the light-shielding portion 40 of this modification has a configuration in which a light-shielding film 103, an etching stopper film 104, a first semi-permeable film 101, and a second semi-permeable film 102 are laminated on a translucent substrate 100. Specifically, the light-shielding portion 40 has a configuration in which the second semi-permeable film 102 is formed on the translucent substrate 100, the etching stopper film 104 is formed on the second semi-permeable film 102, the light-shielding film 103 is formed on the etching stopper film 104, and the first semi-permeable film 101 is formed on the light-shielding film 103. The etching stopper film 104 is made of a material that has sufficient etching selectivity between the second semi-permeable film 102 and the light-shielding film 103. With this configuration, a structure (mask blank) in which the second semi-permeable film 102, the etching stopper film 104, and the light-shielding film 103 are pre-deposited on the translucent substrate 100 can be prepared in advance. This reduces the number of interactions between depositing a thin film on the translucent substrate 100 and patterning the thin film, thereby reducing the occurrence of defects caused by these interactions.

[0059] The modified transfer mask 1 can be manufactured, for example, by the following method. First, a second semi-transparent film 102, an etching stopper film 104, and a light-shielding film 103 are deposited on a translucent substrate 100 in that order. After deposition, the light-shielding film 103 and the etching stopper film 104 are patterned to match the shape of the light-shielding portion 40 (for example, a resist film having the pattern of the light-shielding portion 40 is placed on the light-shielding film 103, and this resist film is used as a mask to perform wet etching or dry etching using different etchants to form the pattern of the light-shielding portion 40 on the light-shielding film 103 and the etching stopper film 104). Furthermore, the second semi-permeable film 102 is patterned to match the shape of the first transparent portion 20 and the light-transmitting portion 10 (for example, a resist film having the pattern of the first transparent portion 20 and the light-transmitting portion 10 is placed on the second semi-permeable film 102, and wet etching or dry etching is performed using the resist film as a mask to form the pattern of the first transparent portion 20 and the light-transmitting portion 10 on the second semi-permeable film 102). Subsequently, the first semi-permeable film 101 is deposited on the light-transmitting substrate 100, the second semi-permeable film 102, and the light-shielding film 103, and the first semi-permeable film 101 is patterned to match the shape of the light-transmitting portion 10 (for example, a resist film having the pattern of the light-transmitting portion 10 is placed on the first semi-permeable film 101, and wet etching or dry etching is performed using the resist film as a mask to form the pattern of the light-transmitting portion 10 on the first semi-permeable film 101).

[0060] (4-2) Modification 2 of the first embodiment Figure 5 is a schematic cross-sectional view of the transfer mask 1 of this modified example. The transfer mask 1 of this modified example, like the first embodiment described above, has a transfer pattern on a translucent substrate 100 and has a translucent portion 10, a first translucent portion 20, a second translucent portion 30, and a light-shielding portion 40. Therefore, this modified transfer mask 1 can also reduce the inclination angle θ of the inclined portion 201 located around the opening 200 when forming the PDL.

[0061] As shown in Figure 5, the second transparent portion 30 of this modification has a configuration in which, for example, a first semi-permeable film 101 and an etching stopper film 104 are laminated on a translucent substrate 100. In other words, the etching stopper film 104 plays the role of a second semi-permeable film 102. Therefore, the etching stopper film 104 consists of the first semi-permeable film 101 and the light-shielding film 103 and a material having etching selectivity. In this modification, the etching stopper film 104 may be referred to as the second semi-permeable film 102. Specifically, the second transparent portion 30 has a configuration in which the first semi-permeable film 101 is formed on a translucent substrate 100, and the etching stopper film 104 is formed on the first semi-permeable film 101. Also, as shown in Figure 5, the light-shielding portion 40 of this modification has a configuration in which, for example, a light-shielding film 103, an etching stopper film 104, and the first semi-permeable film 101 are laminated on a translucent substrate 100. Specifically, the light-shielding portion 40 has a configuration in which a first semi-permeable film 101 is formed on the light-transmitting substrate 100, an etching stopper film 104 is formed on the first semi-permeable film 101, and a light-shielding film 103 is formed on the etching stopper film 104. With this configuration, a structure (mask blank) in which a second semi-permeable film 102, an etching stopper film 104 (corresponding to the second semi-permeable film 102), and a light-shielding film 103 are pre-deposited on the light-transmitting substrate 100 can be prepared in advance. This essentially eliminates the interaction between the deposition of a thin film on the light-transmitting substrate 100 and the patterning of that thin film, thereby reducing the occurrence of defects caused by this interaction.

[0062] The transfer mask 1 for this modification can be manufactured, for example, by the following method. First, a mask blank is prepared by depositing a first semi-transparent film 101, an etching stopper film 104, and a light-shielding film 103 in that order on a translucent substrate 100. After film deposition, first, the light-shielding film 103 is patterned to match the shape of the light-shielding portion 40 (for example, a resist film having the pattern of the light-shielding portion 40 is placed on the light-shielding film 103, and the resist film is used as a mask to perform wet etching or dry etching to form the pattern of the light-shielding portion 40 on the light-shielding film 103). Next, the etching stopper film 104 is patterned to match the shape of the first transparent portion 20 and the translucent portion 10 (for example, a resist film having the pattern of the first transparent portion 20 and the translucent portion 10 is placed on the etching stopper film 104, and the resist film is used as a mask to perform wet etching or dry etching to form the pattern of the first transparent portion 20 and the translucent portion 10 on the etching stopper film 104). Furthermore, the first semi-permeable film 101 is patterned to match the shape of the light-transmitting portion 10 (for example, a resist film having the pattern of the light-transmitting portion 10 is placed on the first semi-permeable film 101, and wet etching or dry etching is performed using the resist film as a mask to form the pattern of the light-transmitting portion 10 on the first semi-permeable film 101). [Examples]

[0063] Next, embodiments of the present invention will be described. These embodiments are examples of the present invention, and the present invention is not limited to these embodiments.

[0064] (1) Example 1 Under the following conditions, the inclination angle θ of the inclined portion 201 when PDL was formed by exposure transfer onto a photosensitive polyimide film on a substrate using transfer mask 1 was calculated by simulation. The results are shown in Figure 6. Transmittance T1 of the first transparent section 20: 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% Transmittance T2 of the second transparent section 30: 30% Difference ΔT between transmittance T1 and transmittance T2: 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35% Width D of the first transparent section 20: 0~5.0 μm Numerical aperture (NA) of the exposure device: 0.11 Exposure light: i-line

[0065] As shown in Figure 6, it was confirmed that the tilt angle θ is smaller when the first transparent section 20 is provided (difference ΔT is 5%, 10%, 15%, 20%) compared to when the first transparent section 20 is not provided (difference ΔT is 0%). In particular, it was confirmed that when the difference ΔT is 10% or more and the width D is 1.5 μm or more, the tilt angle θ can be reduced by 5 degrees or more compared to when the first transparent section 20 is not provided.

[0066] (2) Example 2 Furthermore, the inclination angle θ of the inclined portion 201 when the PDL was formed using the transfer mask 1 was calculated by simulation under the following conditions. The results are shown in Figure 7. Transmittance T1 of the first transparent section 20: 30%, 35%, 40%, 45%, 50% Transmittance T2 of the second transparent section 30: 30% Difference ΔT between transmittance T1 and transmittance T2: 0%, 5%, 10%, 15%, 20% Width D of the first transparent section 20: 0~5.0 μm Numerical aperture (NA) of the exposure device: 0.1 Exposure light: Composite light including g-line, h-line, and i-line

[0067] As shown in Figure 7, it was confirmed that the tilt angle θ is smaller when the first transparent section 20 is provided (difference ΔT is 5%, 10%, 15%, 20%) compared to when the first transparent section 20 is not provided (difference ΔT is 0%). In particular, it was confirmed that when the difference ΔT is 10% or more and the width D is 1.5 μm or more, the tilt angle θ can be reduced by 5 degrees or more compared to when the first transparent section 20 is not provided.

[0068] (3) Summary Based on the results of Example 1 and Example 2, we selected the conditions under which the inclination angle θ could be kept to 30 degrees or less, the conditions under which the inclination angle θ could be kept to 25 degrees or less, and the conditions under which the inclination angle θ could be kept to 20 degrees or less, and summarized them in Figure 8. The dashed lines shown in Figure 8 are straight-line approximations of the three conditions with the smallest width D for each of the selected conditions where the difference ΔT is 10%, 15%, and 20%.

[0069] As shown in Figure 8, when the difference ΔT is 10%, 15%, and 20%, the three points with the smallest width D were approximated by a straight line, and the resulting equation was D = -3.14 × ΔT / 100 + 2.32. Therefore, it was confirmed that the inclination angle θ of the inclined section 201 can be made smaller (for example, 30 degrees or less) by making the width D of the first transparent section 20 and the difference ΔT between transmittance T1 and transmittance T2 satisfy the relationship D ≥ -3.14 × ΔT / 100 + 2.32.

[0070] <Other embodiments of the present invention> Although embodiments of the present invention have been specifically described above, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0071] For example, in the above embodiment, a transfer mask 1 having a light-shielding portion 40 provided adjacent to the second transparent portion 30 was described, but the transfer mask 1 does not necessarily have to have a light-shielding portion 40. In this case, for example, a separate transfer mask for forming the column portion 202 may be prepared, and the opening 200 and column portion 202 of the PDL may be formed using a plurality of transfer masks. [Explanation of symbols]

[0072] 1 Transfer mask 10 Translucent part 20 1st transparent section 30 2nd transparent section 40 Light-shielding part 100 Translucent substrate 101 First semi-permeable membrane 102 Second semi-permeable membrane 103 Light-shielding film 104 Etching stopper film 200 opening 201 Slope 202 Column section 203 Flat area

Claims

1. A step of preparing a transfer mask on a translucent substrate, which has a transfer pattern including a translucent portion, a first translucent portion, and a second translucent portion, A step of forming a photosensitive resin film on a substrate that is sensitive to exposure light, A step of irradiating the photosensitive resin film with the exposure light transmitted through the transfer mask using an exposure apparatus to expose and transfer the transfer pattern, The process involves developing the photosensitive resin film that has been exposed and transferred, A method for manufacturing a display device having the following: The exposure transfer step involves exposing and transferring the transfer pattern such that an inclined portion with a cross-sectional inclination angle of 30 degrees or less is formed around the opening of the photosensitive resin film after the development process. The light-transmitting portion has a hole shape in which the light-transmitting substrate is exposed. The first transmissive portion is provided in an annular shape along the outer circumference of the light-transmitting portion, The second permeable portion is provided in contact with the outer circumference of the first permeable portion, The transmittance T1 of the first transmission portion to the exposure light is higher than the transmittance T2 of the second transmission portion to the exposure light. The absolute value of the phase difference between the exposure light transmitted through the first transmission portion and the exposure light transmitted through the light-transmitting portion is 90 degrees or less. The absolute value of the phase difference between the exposure light transmitted through the second transmissive portion and the exposure light transmitted through the light-transmitting portion is 90 degrees or less. The absolute value of the phase difference between the exposure light transmitted through the first transmission portion and the exposure light transmitted through the second transmission portion is 90 degrees or less. A method for manufacturing a display device, characterized by the following:

2. The method for manufacturing a display device according to claim 1, characterized in that the exposure light includes light with a wavelength of 313 nm or more and 436 nm or less.

3. The method for manufacturing a display device according to claim 1, characterized in that the width D of the first transparent portion is 1.5 μm or more.

4. The method for manufacturing a display device according to claim 1, characterized in that the difference ΔT between the transmittance T1 and the transmittance T2 is 10% or more.

5. The width D of the first transparent portion and the difference ΔT between the transmittance T1 and the transmittance T2 are, A method for manufacturing a display device according to claim 1, characterized in that the relationship D ≥ -3.14 × ΔT / 100 + 2.32 is satisfied.

6. The method for manufacturing a display device according to claim 1, characterized in that the transmittance T1 is 20% or more.

7. The method for manufacturing a display device according to claim 1, characterized in that the transmittance T2 is 10% or more.

8. The method for manufacturing a display device according to claim 1, characterized in that the transfer mask further has a light-shielding portion provided adjacent to the second transparent portion.

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