TW201837553A - Photomask for use in manufacturing a display device and method of manufacturing a display device - Google Patents

Abstract

To provide a photomask which is capable of achieving both excellent resolution and production efficiency under exposure conditions applied to manufacture of a display device. A photomask has a transfer pattern which is a hole pattern for forming a hole on a transfer object. The transfer pattern has a light-transmitting portion having a diameter Wl ([mu]m) where a transparent substrate is exposed, a light-shielding rim portion having a width R ([mu]m) surroun ding the light-transmitting portion, and a phase shift portion surrounding the light-shielding rim portion. A phase difference between the phase shift portion and the light-transmitting portion is approximately 180 degrees with respect to light having a representative wavelength of exposure light. In light intensity distribution formed on the transfer object by the exposure light transmitting the phase shift portion located at one side of the light-transmitting portion, the photomask satisfies a condition (dl - 0.5 x Wl) ≤ R ≤ (d2 - 0.5 x W1) where dl ([mu]m) represents a distance from a boundary position between the phase shift portion and the light-shielding rim portion towards the light-shielding rim portion to a minimum point Bl of a first valley and d2 ([mu]m) represents a distance from the boundary position to a minim um point B2 of a second valley.

Description

Photomask for manufacturing display device and method for manufacturing display device

The present invention relates to a photomask used for manufacturing an electronic device, particularly a photomask suitable for manufacturing a flat panel display (FPD), and a method for manufacturing a display device using the same.

As a photomask used for manufacturing a semiconductor device, a halftone type phase shift photomask is known in the industry. FIG. 11 is a structural example showing a conventional halftone type phase shift mask. FIG. 11 (a) is a schematic plan view, and FIG. 11 (b) is a schematic cross-sectional view at a position B-B in FIG. 11 (a). In the illustrated halftone type phase shift mask, a phase shift film 101 is formed on a transparent substrate 100, and the phase shift film 101 is patterned to form a hole pattern. The hole pattern includes a light transmitting portion 103 exposing the transparent substrate 100. The phase shift portion 104 is surrounded by the hole pattern. The phase shift section 104 includes a phase shift film 101 formed on the transparent substrate 100. The transmittance of the exposure light of the phase shift section 104 is set to, for example, about 6%, and the phase shift amount is set to about 180 degrees. At this time, the light transmitted through the light-transmitting portion 103 and the light transmitted through the phase-shifting portion 104 are in reverse phase with each other. The light in the opposite phase interferes near the boundary between the light transmitting portion 103 and the phase shifting portion 104, and exerts the effect of improving the analysis performance. It is known that compared with the so-called binary mask, the halftone type phase shift mask described above not only improves the analytical performance in the depth of focus (DOF), but also improves the effect. [Prior Art Documents] [Non-Patent Documents] [Non-Patent Documents 1] Tanabe Gong, Hakuho Morihisa, Takeichi Yoichi, "Getting Started with Mask Technology", Industrial Survey Corporation, December 15, 2006, p.245

[Problems to be Solved by the Invention] In a display device including a liquid crystal display device (Liquid crystal display) or an organic EL (Organic Electro Luminescence) display device, in addition to expecting a brighter and power-saving display device In addition, improvements in high-definition, high-speed display, and wide viewing angle display performance are also desired. For example, as for the thin film transistor ("TFT") used in the above display device, if the contact hole formed in the interlayer insulating film among the plurality of patterns constituting the TFT does not have a pattern connecting the upper layer with the lower layer The effect of the pattern does not guarantee correct operation. On the other hand, in order to increase the aperture ratio of a liquid crystal display device as much as possible and to become a bright and power-saving display device, the pursuit of sufficiently small contact hole diameters, etc., is accompanied by the demand for higher density of display devices, and the pattern of holes is expected. The diameter is also reduced (for example, less than 3 μm). For example, a hole pattern having a diameter of 0.8 μm or more and 2.5 μm or less and a diameter of 2.0 μm or less must be considered. Specifically, formation of a pattern having a diameter of 0.8 to 1.8 μm is expected. On the other hand, compared with display devices, in the field of photomasks for manufacturing semiconductor devices (LSIs) that have a high degree of integration and that miniaturization of patterns has significantly progressed, there is a high number of openings NA (for example, An optical system exceeding 0.2) is applied to an exposure device to promote the shortening of the exposure light. As a result, KrF or ArF excimer lasers (single wavelengths of 248 nm and 193 nm, respectively) are mostly used in this field. On the other hand, in the field of lithography for display device manufacturing, in order to improve the resolution, the method as described above is generally not applied. For example, the NA (number of openings) of the optical system of the exposure device used in this field is about 0.08 to 0.12, and even in the future, there will still be an environment of about 0.08 to 0.20. In addition, i-line, h-line, or g-line light sources are often used as exposure light sources. By using a wide-wavelength light source mainly including the light source to obtain a large amount of light for irradiating a large area, the tendency to value production efficiency and cost is strong. . Also in the manufacture of a display device, the demand for miniaturization of a pattern as described above becomes high. Here, there are several problems in applying the technology for manufacturing a semiconductor device to the manufacturing of a display device as it is. For example, in order to convert to a high-resolution exposure device having a high NA (number of openings), a large investment must be made, and the price cannot be consistent with that of a display device. Moreover, changes to the exposure wavelength (using short wavelengths such as ArF excimer lasers) are disadvantageous in that a considerable investment is still required. That is, the cost and efficiency of pursuing the miniaturization of previously unavailable patterns without compromising the existing advantages have become a problem of photomasks for display device manufacturing. According to the research by the present inventors, it is clear that when the halftone type phase shift mask shown in FIG. 11 is used as a mask for manufacturing a display device, there are problems described below, and there is room for further improvement. There are the following elements (1) to (3) for the performance desired for a photomask. (1) Depth of Focus (DOF) In the case where defocus occurs during exposure, it is ideal for the depth of focus (DOF) to make the change of CD within a specific range (for example, within ± 10%) relative to the target CD. The value is high. If the value of DOF is high, it is difficult to be affected by the flatness of the object to be transferred, and the pattern transfer is performed stably. Here, the abbreviation of CD-based Critical Dimension means a pattern width. The size of the photomask used in the manufacture of the display device is larger than that of the photomask used in the manufacture of the semiconductor device, and the transfer target (display substrate, etc.) is also large in size. Since it is difficult to perfect the flatness of any one, the DOF is improved. The value of the mask is significant. (2) Mask Error Enhancement Factor (MEEF: Mask Error Enhancement Factor) This is a numerical value representing the ratio of the CD error on the photomask to the CD error of the pattern formed on the transferred body. Generally speaking, the smaller the pattern is, the easier the CD error on the mask will be on the transferee. However, by reducing the MEEF as much as possible, the accuracy of the CD formed on the transferee can be improved. . Due to the evolution of the specifications of display devices, the need for miniaturization of patterns and the need for a photomask with a pattern close to the analytical limit of the exposure device is also true for photomasks used in the manufacture of display devices. high. (3) Eop This is the amount of exposure light necessary to form a pattern of a target size on a target. In the manufacture of a display device, the size of the photomask substrate is large (for example, the main surface is a quadrangle with 300 to 2000 mm on one side). Therefore, if a mask with a high value of Eop is used, it is necessary to reduce the speed of scanning exposure, which hinders production efficiency. Therefore, when manufacturing a display device, it is desirable to use a mask capable of reducing the value of Eop. According to the research by the present inventors, it is known that the improvement effect of DOF is obtained in the halftone type phase shift mask shown in FIG. 11 described above, and on the other hand, it is expected to further improve the point of Eop and MEEF. Specifically, it can be seen that if the above-mentioned halftone type phase shift mask is used, the required light amount (Dose) increases due to the loss of light intensity. Therefore, Eop increases significantly, and the MEEF tends to increase with this. There are still problems with photomasks used in the manufacture of display devices. Therefore, an object of the present invention is to provide a photomask capable of achieving both excellent resolution and production efficiency under exposure conditions used in the manufacture of a display device. [Technical means to solve the problem] (First aspect) The first aspect of the present invention is characterized in that it is a mask for manufacturing a display device having a pattern for transfer on a transparent substrate; and the aforementioned transfer The pattern is a hole pattern for forming a hole in the object to be transferred, and the transfer pattern includes: exposing the light-transmitting portion having a diameter of W1 (μm) of the transparent substrate; and a width surrounding the light-transmitting portion is R (μm) a light-shielding edge portion; and a phase-shifting portion surrounding the light-shielding edge portion; and a phase difference between the phase-shifting portion and the light-transmitting portion with respect to light of a representative wavelength of the exposure light is approximately 180 degrees; In the light intensity distribution of the exposure light of the phase shifting portion on one side of the light transmitting portion formed on the object to be transferred, when the boundary position between the phase shifting portion and the light shielding edge portion faces the light shielding edge portion side, When the distance from the minimum point B1 of the first valley is d1 (μm), and when the distance from the minimum point B2 of the second valley is d2 (μm), (d1-0.5 × W1) ≦ R ≦ (d2 -0.5 × W1). (Second aspect) The photomask of the second aspect of the present invention is characterized in that it is a photomask for manufacturing a display device having a pattern for transfer on a transparent substrate; and the pattern for transfer is for use in a substrate. A hole pattern is formed on the transfer body, and the transfer pattern includes: exposing the light-transmitting portion with a diameter W1 (μm) of the transparent substrate; and a light-shielding edge portion having a width R (μm) surrounding the light-transmitting portion And a phase shifting portion surrounding the light shielding edge portion; and a phase difference between the phase shifting portion and the light transmitting portion with respect to light having a representative wavelength of the exposure light is approximately 180 degrees; and the transmission is located at one side of the light transmitting portion In the light intensity distribution of the exposure light of the phase shift portion on the transferee, when the boundary position between the phase shift portion and the light shielding edge portion faces the light shielding edge portion side, the maximum point of the first peak will be indicated. Of the two points of 1/2 of the light intensity of P, the point of the inclined portion on the side close to the light-shielding edge portion of the first peak is set to Q1, and the point of the inclined portion on the side away from the light-shielding edge portion is set to Q1. Q2, the distance from the aforementioned boundary position to Q1 Is set to d3, the distance from the boundary position Q2 when it is set to d4, (d3-0.5 × W1) ≦ R ≦ (d4-0.5 × W1). (Third aspect) The third aspect of the present invention is the photomask according to the first aspect or the second aspect, wherein the transfer pattern is used to form a diameter W2 on the object to be transferred ( The hole pattern of the holes of W2 ≦ W1). (Fourth aspect) The fourth aspect of the present invention is the photomask according to any one of the first to third aspects, wherein the phase shifting portion has a transmission of 2 to 10% with respect to the light of the representative wavelength. rate. (Fifth aspect) The fifth aspect of the present invention is the photomask according to any one of the first to fourth aspects, which is used for the number of openings (NA) of 0.08 or more and less than 0.20 and has an i A multiple-fold projection exposure device of an exposure light source of -line, h-line, or g-line exposes the aforementioned pattern for transfer, and forms a hole having a diameter W2 of 0.8 to 3.0 (μm) in the transfer target. (Sixth aspect) A method for manufacturing a display device, including the following steps: a step of preparing a photomask as in any one of the first to fourth aspects; and the number of openings (NA) is 0.08 to 0.20 and An equal magnification projection exposure apparatus having an exposure light source including i-line, h-line, or g-line exposes the aforementioned pattern for transfer, and forms a hole having a diameter W2 of 0.8 to 3.0 (μm) in the object to be transferred. The steps. [Effects of the Invention] According to the present invention, it is possible to provide a photomask capable of achieving both excellent resolution and production efficiency under exposure conditions applied to the manufacture of a display device.

FIG. 1 (a) is a cross-sectional view showing a half-type phase shift mask of the previous type, and FIG. 1 (b) is a view showing the light transmitted through the phase-shifted portion of one side of the light transmitting portion in FIG. 1 (a) Graph of amplitude. In addition, FIG. 1 (b) shows the amplitude of the light transmitted through the phase shift section 104 located on the left side of the light transmitting section 103. It is shown that the light transmitted through the phase shift portion 104 located on the right side of the light transmitting portion 103 forms a transmitted light amplitude that is bilaterally symmetrical with respect to the center of the light transmitting portion 103 and the transmitted light amplitude of FIG. 1 (b), but the illustration is omitted here. . Here, when the phase of the light (not shown) transmitted through the light-transmitting portion 103 is set to the (+) phase, the phase shift portion 104 passes through the phase-shifted portion 104 and reaches the center of the left side of the light-transmitting portion 103 near the center. The light in the corresponding area becomes the (-) phase. This light interferes with light having a (+) phase transmitted through the light transmitting portion 103. Therefore, the intensity of the light transmitted through the light transmitting portion 103 is relatively weakened. That is, due to the interference between the light of the (+) phase and the light of the (-) phase, the intensity of the light that has passed through the light transmitting portion 103 and reached the object to be transferred decreases. This phenomenon becomes remarkable when the size of the light transmitting portion 103 is reduced. However, the amplitude curve of the light passing through the phase shifting portion 104 is closer to the transparent portion 103 side (right side in the figure) from the above-mentioned boundary position, and its phase is changed to the (+) side, and a point having a maximum value of the light amplitude is formed. peak. Therefore, the present inventors have studied the possibility of obtaining an improvement effect of Eop and MEEF by increasing the light intensity instead of suppressing the aforementioned light intensity reduction by using the (+) phase transmitted light of the portion forming the peak. Sex. FIG. 2 is a diagram illustrating a study on a method for changing the phase of light to the peak on the (+) side in the above-mentioned FIG. 1 (b) at a position corresponding to the light-transmitting portion on the transfer target. Here, the light-shielding edge portion 105 is formed by the light-shielding film 106 near the edge on the light-transmitting portion 103 side of the phase shifting portion 104. When the light shielding edge portion 105 is formed as described above, the portion of the phase shift film 101 covered by the light shielding film 106 does not function as the phase shift portion 104. Therefore, the edge on the light transmitting portion 103 side of the phase shifting portion 104 is shifted to the left side compared to a case where the light shielding edge portion 105 is not formed. This means shifting the amplitude curve of the light of the phase shifting section 104 to the left. As a result, the portion of the amplitude curve of the light passing through the phase shift section 104 whose phase is changed to a peak on the (+) side is shifted to the left. Therefore, the vicinity of the maximum point of the amplitude curve forming the peak can be located within the width dimension of the light transmitting portion 103 (preferably, the center position of the light transmitting portion 103 or its vicinity). In this way, the exposure light can be used more efficiently. The present invention has been completed based on the findings of the present inventors as described above. <Configuration of Photomask of Embodiment> FIG. 3 shows an example of the configuration of a photomask of an embodiment of the present invention. FIG. 3 (a) is a schematic plan view, and FIG. 3 (b) is a view at the AA position of FIG. 3 (a). Cutaway schematic. The photomask shown in the figure is a photomask for manufacturing a display device having a pattern for transfer provided on the transparent substrate 10. This transfer pattern is a hole pattern for forming a hole in a body to be transferred, and has a light-transmitting portion 11 with a diameter W1 (μm) exposed from the transparent substrate 10, and a width R (μm) surrounding the light-transmitting portion 11. ), And the light shielding edge portion 12 and the phase shifting portion 13 surrounding the light shielding edge portion 12. The transparent substrate 10 is made of transparent glass or the like. In the light-shielding edge portion 12, a light-shielding film 15 is formed on the transparent substrate 10 (the phase shift film 14 in FIG. 3). The optical density (OD) of the light-shielding film 15 is preferably OD ≧ 2, and more preferably OD ≧ 3. The light shielding edge portion 12 may be a single layer of the light shielding film 15 or a laminated film of the phase shift film 14 and the light shielding film 15. The stacking order of the phase shift film 14 and the light shielding film 15 (the positional relationship in the thickness direction of the transparent substrate 10) is not particularly limited. The material of the light-shielding film 15 may be Cr or a compound thereof (oxide, nitride, carbide, oxynitride, or carbon oxynitride), or may be a metal compound including Mo, W, Ta, and Ti. The metal compound may be a metal silicide or a compound of the silicide. In addition, the material of the light-shielding film 15 can be wet-etched, and a material having an etching selectivity with respect to a material (described later) of the phase shift film 14 is preferable. In addition, the light shielding film 15 and the phase shift film 14 may be provided with a reflection control layer for controlling reflection of light on the front side and / or the back side. The phase shift portion 13 is a phase shift film 14 formed on the transparent substrate 10. The phase shift film 14 may be Cr or a compound thereof (oxide, nitride, carbide, oxynitride, or carbon oxynitride), or may be a metal compound including Mo, W, Ta, and Ti. The metal compound may be a silicide of a metal or the above-mentioned compound of the silicide. The material of the phase shift film 14 may be a material containing any of Zr, Nb, Hf, Ta, Mo, Ti and Si, or an oxide, nitride, oxynitride, carbide containing these materials, or The material of the oxynitride is formed of the above-mentioned compound of Si. The material of the phase shift film 14 is preferably a material capable of performing wet etching. In the photomask of FIG. 3, in order to perform wet etching, it is preferable that no deep side etch is generated near the cross section of the light-transmitting portion side of the phase shift film 14 and the interface between the light-shielding film 15. Specifically, it is preferable to select the material and film quality of the phase shift film 14 in such a manner that the width does not exceed the film thickness of the phase shift film 14 even if side etching occurs. Here, the phase difference φ1 between the phase shifting section 13 and the light transmitting section 11 with respect to light having a representative wavelength of the exposure light is approximately 180 degrees. The term "approximately 180 degrees" means 120 to 240 degrees. The phase difference φ1 is preferably 150 to 210 degrees. In addition, the wavelength dependence of the phase shift amount of the phase shift film 14 is preferably within 40 degrees with respect to the variation widths of i-line, h-line, and g-line. The light-shielding edge portion 12 forms a light-shielding film 15 on a transparent substrate 10 (phase shift film 14 in FIG. 3) that substantially does not transmit light of a representative wavelength of exposure light and has an optical density OD of 2 or more (preferably OD ≧ 3). The phase shift section 13 preferably has a transmittance T1 (%) of 2 to 10% with respect to light having a representative wavelength of the exposure light. The transmittance T1 is more preferably 3 to 8%, and even more preferably 3 <T1 <6. When the transmittance T1 is too high, a disadvantageous layer that easily damages the remaining film thickness is easily generated in the resist pattern formed on the object to be transferred, and if the transmittance T1 is too low, it will be difficult to obtain the countermeasures described below. Contribution of phase-transmitted light intensity curve. The transmittance T1 here is the transmittance of light of the above-mentioned representative wavelength when the transmittance of the transparent substrate 10 is based on (100%). In addition, light including any one of i-line, h-line, and g-line, or wide-wavelength light including all of i-line, h-line, and g-line may be used as the exposure light. As the representative wavelength, any one of the wavelengths included in the light used for exposure (for example, i-line) is used. In the photomask of this embodiment, the diameter W1 (μm) of the light transmitting portion 11 is preferably 0.8 ≦ W1 ≦ 4.0. In the transfer pattern illustrated in FIG. 3, the plan view shape of the light transmitting portion 11 is a square, and the diameter W1 at this time is a dimension of one side of the square. When the plan view shape of the light transmitting portion 11 is rectangular, the dimension of the long side is set to the diameter W1. The shape of the light transmitting portion 11 is preferably a quadrangle, and particularly preferably a square. If the diameter W1 is too large, the resolution limit size of the exposure device for a display device is sufficiently exceeded, so that a sufficient resolution can be obtained by the previous photomask, and the improvement effect of the present invention is not significantly generated. On the other hand, if the diameter W1 is too small, it is difficult to obtain an accurate CD stably during the manufacture of the photomask. More preferably, 0.8 ≦ W1 ≦ 3.5. When further miniaturization is desired, it may be set to 1.0 <W1 <3.0, and further set to 1.2 <W1 <2.5. When a hole having a diameter of W2 (μm) is formed in the object to be transferred using the transfer pattern provided in the mask of this embodiment, it is preferably 0.8 ≦ W2 ≦ 3.0. The diameter W2 of the hole formed in the body to be transferred refers to the length of the largest part of the distance between the two opposing sides. Specifically, the relationship between the diameter W1 of the light transmitting portion 11 of the photomask and the diameter W2 of the hole of the transferred body is preferably W1 ≧ W2, and more preferably W1> W2. Moreover, if β (μm) is set as the mask deviation value (W1-W2) and β> 0 (μm), the mask deviation value β (μm) is preferably 0.2 ≦ β ≦ 1.0, and more preferably 0.2 ≦ β ≦ 0.8. FIG. 4 (a) is a plan view showing a portion of a transfer pattern (a portion surrounded by a dotted line in FIG. 3) when the width of the light-shielding edge portion is set to be relatively narrow in the photomask according to the embodiment of the present invention. FIG. 4 (b) is a graph showing the light intensity distribution of the transmitted light passing through the phase shift portion on the left side of the mask on the object to be transferred at this time. 5 (a) is a plan view showing a portion of a transfer pattern (a portion surrounded by a dotted line in FIG. 3) when the width of the light-shielding edge portion is set to be relatively wide in the mask according to the embodiment of the present invention. FIG. 5 (b) is a diagram showing the light intensity distribution of the transmitted light passing through the phase shift portion on the left side of the photomask on the object to be transferred. As shown in FIG. 4 (b) and FIG. 5 (b), if the exposure light transmitted through the phase shifting portion 13 located on one side (left side in the figure) of the light transmitting portion 11 is drawn on a curve, In the light intensity distribution, the first valley, the first peak, and the second valley appear from the boundary position of the phase shift portion 13 and the light shielding edge portion 12 toward the light shielding edge portion 12 (right side in the figure). The first peak corresponds to a peak whose portion is shifted to the (+) side in the amplitude curve of the light shown in FIG. 1 described above. Here, the distance from the boundary position to the minimum point B1 (Figure 4) in the first valley is set to d1 (μm), and the distance to the minimum point B2 (Figure 5) in the second valley is set to d2. In the case of (μm), the width R (μm) of the light shielding edge portion 12 is preferably set so as to satisfy the following formula (1). (d1-0.5 × W1) ≦ R ≦ (d2-0.5 × W1) (1) In addition, FIG. 4 shows the lower limit of the width R of the light-shielding edge portion 12 in the above formula (1), and FIG. 5 shows the width The upper limit of R is displayed. If the width R of the light-shielding edge portion 12 is set so as to satisfy the above formula (1), the transmitted light of the (+) phase of the transmitted light of the phase shift portion 13 can be located at the center of the light-transmitting portion 11. That is, at least a part of the (+) phase portion of the transmitted light that has passed through the phase shift portion 13 can reach the object to be transferred together with the transmitted light that has passed through the (+) phase of the light transmitting portion 11, thereby improving its The effect of the peak of light intensity. Next, the pattern configuration for allowing a larger part of the (+) phase in the transmitted light transmitted through the phase shifting section 13 to reach the transfer target will be studied using FIGS. 6 and 7. FIG. 6 (a) is a plan view showing a portion of a transfer pattern (a portion surrounded by a dotted line in FIG. 3) when the width of the light-shielding edge portion is set to be relatively narrow in the photomask according to the embodiment of the present invention. FIG. 6 (b) is a graph showing the light intensity distribution of the transmitted light passing through the phase shift portion on the left side of the mask on the object to be transferred at this time. 7 (a) is a plan view showing a portion of a transfer pattern (a portion surrounded by a dotted line in FIG. 3) when the width of the light-shielding edge portion is set to be relatively wide in the mask according to the embodiment of the present invention. FIG. 7 (b) is a diagram showing a light intensity distribution of the transmitted light passing through the phase shift portion on the left side of the photomask on the object to be transferred at this time. As shown in FIG. 6 (b) and FIG. 7 (b), if the exposure light passing through the phase shift section 13 located on one side (left side in the figure) of the light transmitting section 11 is drawn in a curve, it is formed on the object to be transferred. In the light intensity distribution, similar to the above, the first valley, the first peak, and the second valley appear at the boundary position between the phase shift portion 13 and the light shielding edge portion 12 toward the light shielding edge portion 12 (right side in the figure). At this time, the point of the inclined portion located on the side (left side in the figure) of the first peak near the light shielding edge portion 12 of the two points representing 1/2 of the light intensity of the maximum point P of the first peak is set as For Q1, set the point of the inclined part on the side (right side in the figure) away from the shading edge part 12 as Q2, set the distance from the above boundary position to Q1 as d3 (Figure 6), and set the distance from the above boundary position to Q2 When the distance is set to d4 (FIG. 7), the width R (μm) of the light shielding edge portion 12 is preferably set in a manner that satisfies the following formula (2). (d3-0.5 × W1) ≦ R ≦ (d4-0.5 × W1) (2) In addition, FIG. 6 shows the lower limit of the width R of the shading edge portion 12 in the above formula (2), and FIG. 7 shows the upper limit. Display it. If the width R of the light-shielding edge portion 12 is set so as to satisfy the above formula (2), the (+) phase of the transmitted light of the phase shift portion 13 and the light intensity portion (about half of the upper portion) can be located. The center of the light transmitting portion 11. That is, the portion of the (+) phase near the peak (maximum point P) of the (+) phase of the transmitted light transmitted through the phase shifting portion 13 can be reliably located near the center within the size of the light transmitting portion 11 and reaches the object to be transferred. The effect of increasing the peak of its light intensity is obtained more effectively. According to the mask of this embodiment, it is possible to shift the position of the portion of the amplitude curve of the light transmitted through the phase shift portion 13 that is converted to the peak of the (+) phase, so that more portion of the peak of the (+) phase is located in the light transmitting portion. 11 size. Thereby, the exposure light can be used more effectively. As a result, it is possible to achieve both excellent resolution and production efficiency under exposure conditions used in the manufacture of display devices. Specifically, for example, under exposure conditions where the number of openings (NA) is 0.08 ≦ NA ≦ 0.20 and the correlation factor (σ) is 0.4 ≦ σ ≦ 0.9, a mask having excellent MEEF and Eop can be realized. The number of openings (NA) is more preferably 0.08 <NA <0.20, and even more preferably 0.10 <NA <0.15. On the other hand, the correlation factor (σ) is more preferably 0.4 <σ <0.7, and even more preferably 0.4 <σ <0.6. The transfer pattern of the photomask of this embodiment is used for forming a hole in the body to be transferred, and includes a transparent portion having a diameter of W1 (μm) exposed on the transparent substrate, and a width surrounding the transparent portion is A light-shielding edge portion of R (μm) and a phase shift portion surrounding the light-shielding edge portion. In other words, the effects of improving MEEF and Eop can be obtained without including other structures for forming the holes (auxiliary patterns for assisting transferability, etc.). The photomask of this embodiment is suitably used as a photomask for forming isolated holes in a target, or a photomask for forming dense holes in a target. The so-called dense pores mean that a plurality of pore patterns are regularly arranged and produce optical effects on each other. The present invention includes a manufacturing method of a display device that uses the photomask of this embodiment to expose the exposure pattern to transfer the pattern for transfer to a transfer target. In the method for manufacturing a display device of the present invention, first, a photomask of this embodiment is prepared. Next, the pattern for transfer is exposed using an exposure device, and a hole having a diameter W2 of 0.8 to 3.0 (μm) is formed in the object to be transferred. For exposure, an exposure device having an opening number (NA) of 0.08 to 0.20 and having an exposure light source including i-line, h-line, or g-line is used. Moreover, it is preferable to use an exposure device that performs equal-magnitude projection exposure for the exposure, and the opening number (NA) of the optical system is 0.08 to 0.20 (the correlation factor (σ) is 0.4 to 0.9) and is included in the exposure light An exposure device for an exposure light source of at least one of i-line, h-line, and g-line. When a single wavelength is used for the exposure light, i-line is preferably used. In addition, wide-wavelength light including all of i-line, h-line, and g-line can be used as the exposure light. Although the light source of the exposure device used can use oblique illumination (ring illumination, etc.) other than the normal incidence component, the normal effect including the normal incidence component can also be used to obtain the excellent effect of the present invention without using oblique illumination. . The photomask according to the embodiment of the present invention can be manufactured, for example, by preparing a blank photomask having a phase shift film 14 and a light shielding film 15 laminated on the transparent substrate 10 in order, and patterning the two films separately. A well-known film formation method such as a sputtering method may be applied to the film formation of the phase shift film 14 and the light-shielding film 15. When manufacturing a photomask, a well-known photoresist can be used in the photolithography step, and a laser drawing device or the like can be used. When the photomask of FIG. 3 is manufactured, it is desirable to precisely control the width R of the light shielding edge portion 12. This is because it affects the contour of the spatial image formed on the transferee during exposure. Preferably, when manufacturing the photomask of FIG. 3, drawing is performed with respect to the blank photomask on which the resist film is formed. First, the light-shielding film 15 is etched to form a light-shielding edge portion 12 (define the light-shielding edge portion). Next, a resist film is formed again, and the phase shift film 14 is drawn and etched to form a light transmitting portion 11. Next, an optical simulation performed using the mask according to the embodiment of the present invention will be described. In the optical simulation, a mask having a transfer pattern (hole pattern) similar to that shown in FIG. 3 described above was used. At this time, when the diameter W1 of the light-transmitting portion 11 is set to 2 μm, and a hole with a diameter W2 of 1.5 μm is transferred to the object to be transferred (the mask deviation value β = 0.5 μm), The size of the width R verifies how the optical performance of the MEEF and Eop changes. The transmittance of the exposure light of the phase shift section 13 is set to 5.2% for i-line. The optical conditions used in the simulation are as follows. The optical system of the exposure device has an opening number NA of 0.1 and a correlation factor σ of 0.5. In addition, a light source (wide-wavelength light source) including all of i-line, h-line, and g-line was used for the exposure light source, and the intensity ratio was set to g: h: i = 1: 1: 1. FIG. 8 is a diagram showing a simulation result of the value of MEEF for a change in the width of the light-shielding edge portion, and FIG. 9 is a diagram showing a simulation result of the value of Eop for a change in the width of the light-shielding edge portion. In FIGS. 8 and 9, the horizontal axis edge size (Rim Size) (μm) indicates the width R of the light shielding edge portion 12. In addition, the case where the width R of the light shielding edge portion 12 is 0 corresponds to the case where a halftone type phase shift mask of the same type as the previous type shown in FIG. 11 is used. It can be seen from FIG. 8 that the value of MEEF changes due to the change in the width R of the light shielding edge portion 12, especially when the width R is 0.5 to 1.5 μm, the value of MEEF does not reach 6, and when the width R is 0.5 to 1.0 μm The value of MEEF is suppressed to be lower. At this time, the value of MEEF is lower than 5.25, which is a value lower than half compared with the half-type phase shift mask of the previous type having the light transmitting portion (hole pattern) of the same diameter W1. In addition, it can be seen from FIG. 9 that the Eop of the mask of this embodiment is much lower than that of the conventional half-tone phase shift mask. In particular, the width R of the light shielding edge portion 12 is in the range of 0.5 to 2.0 μm. Reduce the dose required for exposure by more than 25%. In particular, when the width of the light shielding edge portion 12 is 0.75 to 1.5 μm, the dose required for exposure is reduced by more than 35%. FIG. 10 is a spatial image (that is, a light intensity distribution of transmitted light) formed on a target when a photomask (edge width R = 1.0 μm) used in the above-mentioned simulation is exposed by an exposure device. A diagram comparing a space image formed using a binary mask (binary) having a hole pattern of the same diameter and a space image formed using a previous halftone type phase shift mask (Att. PSM). According to the above FIG. 10, it can be known that the spatial image formed by the mask of this embodiment has a higher peak value, a steeper slope (close to vertical) than the spatial image formed by other masks, and is excellent for forming fine holes. Of silhouette.

10‧‧‧ transparent substrate

11‧‧‧Light Transmission Department

12‧‧‧ shading edge

13‧‧‧Phase shift section

14‧‧‧ phase shift film

15‧‧‧Light-shielding film

100‧‧‧ transparent substrate

101‧‧‧phase shift film

103‧‧‧Transmission Department

104‧‧‧Phase shift section

105‧‧‧shading edge

106‧‧‧Light-shielding film

B1‧‧‧Minimum point

B2‧‧‧Minimum point

d1‧‧‧distance

d2‧‧‧distance

d3‧‧‧distance

d4‧‧‧distance

P‧‧‧maximum point

Q1‧‧‧ points

Q2‧‧‧ points

R‧‧‧Width / Edge width

W1‧‧‧ diameter

Fig. 1 (a) is a diagram showing a cross section of a previous halftone type phase shift mask; Fig. 1 (b) is a diagram showing the amplitude of light transmitted through the left side of the light-transmitting portion in Fig. 1 (a) Illustration. Fig. 2 (a) and Fig. 2 (b) are explanations for the portion corresponding to the light-transmitting portion on the object to be transferred, for the portion for converting the phase of light to a peak on the (+) side in Fig. 1 (b). Diagram of the method of study. Fig. 3 is a structural example showing a photomask according to an embodiment of the present invention; Fig. 3 (a) is a schematic plan view; Fig. 3 (b) is a schematic cross-sectional view at the A-A position in Fig. 3 (a). FIG. 4 (a) is a plan view showing a part of a transfer pattern when the width of the light-shielding edge portion is set to be narrow in the mask according to the embodiment of the present invention; and FIG. 4 (b) is a view showing a portion through the mask at this time. A diagram (part 1) of the light intensity distribution of the transmitted light on the transfer target on the left side of the phase shift section. Fig. 5 (a) is a plan view of a part of a transfer pattern when the width of the light-shielding edge portion is set to be wide in the mask of the embodiment of the present invention; A diagram (part 1) of the light intensity distribution of the transmitted light of the phase shift portion on the object to be transferred. FIG. 6 (a) is a plan view showing a part of the transfer pattern when the width of the light-shielding edge portion is set to be narrow in the mask according to the embodiment of the present invention; A diagram (part 2) of the light intensity distribution of the transmitted light on the transfer target on the left side of the phase shift section. FIG. 7 (a) is a plan view of a part of the transfer pattern when the width of the light-shielding edge portion is set to be wide in the photomask according to the embodiment of the present invention; FIG. 7 (b) is a view showing the left side of the photomask transmitted through A diagram (part 2) of the light intensity distribution of the transmitted light of the phase shift portion on the transfer target. FIG. 8 is a graph showing simulation results for MEEF. FIG. 9 is a graph showing simulation results for Eop. FIG. 10 shows an optical image (that is, a light intensity distribution of transmitted light) formed on a transfer target when the photomask (edge width R = 1.0 μm) of this embodiment is exposed using an exposure device, and has the same diameter. An optical image formed by a binary mask (binary) of a hole pattern and an optical image formed by using a previous halftone type phase shift mask (Att. PSM). FIG. 11 shows an example of the structure of a conventional halftone type phase shift mask; FIG. 11 (a) is a schematic plan view; and FIG. 11 (b) is a schematic cross-sectional view at the B-B position of FIG. 11 (a).

Claims (6)

A photomask, which is characterized in that it is a photomask for manufacturing a display device having a pattern for transfer on a transparent substrate; and the pattern for transfer is a hole pattern for forming a hole in a body to be transferred, and The pattern for transfer includes: exposing the light-transmitting portion with a diameter W1 (μm) of the transparent substrate; a light-shielding edge portion having a width R (μm) surrounding the light-transmitting portion; and a phase shift portion surrounding the light-shielding edge portion; And the phase difference between the phase shifting portion and the light transmitting portion with respect to light having a representative wavelength of the exposure light is approximately 180 degrees; the exposure light transmitted through the phase shifting portion located on one side of the light transmitting portion is transferred In the light intensity distribution formed on the body, when the boundary position between the phase shift portion and the light shielding edge portion is toward the light shielding edge portion, the distance from the minimum point B1 of the first valley is set to d1 (μm), and When the distance from the minimum point B2 of the second valley is d2 (μm), (d1-0.5 × W1) ≦ R ≦ (d2-0.5 × W1). A photomask, which is characterized in that it is a photomask for manufacturing a display device having a pattern for transfer on a transparent substrate; and the pattern for transfer is a hole pattern for forming a hole in a body to be transferred, and The pattern for transfer includes: exposing the light-transmitting portion with a diameter W1 (μm) of the transparent substrate; a light-shielding edge portion having a width R (μm) surrounding the light-transmitting portion; and a phase shift portion surrounding the light-shielding edge portion; And the phase difference between the phase shifting portion and the light transmitting portion with respect to light having a representative wavelength of the exposure light is approximately 180 degrees; the exposure light transmitted through the phase shifting portion located on one side of the light transmitting portion is transferred In the light intensity distribution formed on the body, when the boundary position between the phase shift portion and the light shielding edge portion is toward the light shielding edge portion side, two points of 1/2 of the light intensity of the maximum point P of the first peak will be indicated. Of the first peak, the point of the inclined portion near the light-shielding edge portion is Q1, the point of the inclined portion located on the side far from the light-shielding edge portion is Q2, and the distance from the boundary position to Q1 is set. Set to d3, will be from the aforementioned boundary When the distance from the position to Q2 is d4, (d3-0.5 × W1) ≦ R ≦ (d4-0.5 × W1). The photomask of claim 1 or 2, wherein the transfer pattern is a hole pattern for forming a hole having a diameter of W2 (where W2 ≦ W1) on the transferee. For example, the photomask of claim 1 or 2, wherein the phase shift portion has a transmittance of 2 to 10% with respect to the light of the representative wavelength. For example, the reticle of claim 1 or 2 is used to convert the aforementioned conversion using an equal magnification projection exposure device having an opening number (NA) of 0.08 to 0.20 and an exposure light source including i-line, h-line, or g-line. The printing pattern is exposed, and holes having a diameter W2 of 0.8 to 3.0 (μm) are formed in the transfer target. A method for manufacturing a display device, comprising the following steps: a step of preparing a photomask according to any one of claims 1 to 5; and using a number of openings (NA) of 0.08 to 0.20 and having i-line and h-line Or a g-line exposure light source with equal magnification projection exposure device to expose the aforementioned transfer pattern to form a hole with a diameter W2 of 0.8 to 3.0 (μm) in the object to be transferred.