TW202024776A - 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 (µm) where a transparent substrate is exposed, a light-shielding rim portion having a width R (µm) 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 (µm) 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 (µm) represents a distance from the boundary position to a minim um point B2 of a second valley.

Description

Mask for manufacturing display device, and manufacturing method of display device

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

As a photomask for manufacturing semiconductor devices, halftone type phase shift photomasks are known in the industry. Fig. 11 shows an example of the structure of a previous halftone type phase shift mask, Fig. 11(a) is a schematic plan view, and Fig. 11(b) is a schematic cross-sectional view at position B-B in Fig. 11(a). In the halftone type phase shift mask shown in the figure, 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 the transparent portion 103 exposing the transparent substrate 100. The phase shift part 104 is surrounded by the hole pattern. The phase shift part 104 includes a phase shift film 101 formed on the transparent substrate 100. The transmittance of the exposure light of the phase shift part 104 is set to, for example, about 6%, and the phase shift amount is set to about 180 degrees. At this time, the light passing through the light transmitting portion 103 and the light passing through the phase shifting portion 104 are in opposite phases to each other. The light of these opposite phases interferes in the vicinity of the boundary between the light-transmitting portion 103 and the phase shifting portion 104, and exerts an effect of improving the analysis performance. It is known that, compared with the so-called binary mask, the halftone phase shift mask described above not only improves the resolution performance in the depth of focus (DOF). [Prior Technical Literature] [Non-Patent Literature] [Non-Patent Document 1] Tanabe Ko, Homoto Morihisa, Takehana Yoichi, "Introduction to Mask Technology", Industrial Research Council, December 15, 2006, p.245

[The problem to be solved by the invention] In display devices including liquid crystal display (Liquid crystal display, liquid crystal display) or organic EL (Organic Electro Luminescence) display devices, in addition to brighter and more power-saving, high-definition, high-speed Improved display and wide viewing angle display performance. For example, for the Thin Film Transistor ("TFT") used in the above-mentioned display device, if the contact hole formed in the interlayer insulating film among the plural patterns constituting the TFT does not have the pattern connecting the upper layer and the lower layer The function of the pattern does not guarantee correct action. On the other hand, for example, in order to increase the aperture ratio of the liquid crystal display device as much as possible to become a bright and power-saving display device, a sufficiently small diameter of the contact hole is pursued, and the demand for higher density of the display device is expected. The diameter is also miniaturized (for example, less than 3 μm). For example, considering a hole pattern with a diameter of 0.8 μm or more and 2.5 μm or less, and the diameter must be 2.0 μm or less, specifically, it is even expected to form a pattern with a diameter of 0.8 to 1.8 μm. On the other hand, compared with display devices, in the field of photomasks for semiconductor device (LSI) manufacturing where the integration is high and the miniaturization of patterns is significantly improved, there is a high numerical aperture NA (such as The optical system exceeding 0.2) is used in the exposure device to promote the short wavelength 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 the manufacture of display devices, in order to improve the resolution, the above-mentioned methods are generally not applied. For example, the NA (numerical aperture) of the optical system of the exposure device used in this field is about 0.08～0.12, even if looking forward to the future, there are still applications of about 0.08～0.20. In addition, as the light source for exposure, i-line, h-line, or g-line light sources are often used. By using a wide-wavelength light source that mainly includes them, the amount of light used to illuminate a large area is obtained. The tendency to pay attention to production efficiency and cost is Strong. Also, in the manufacture of display devices, the requirements for miniaturization of patterns as described above are becoming higher. Here, there are several problems in applying the technology used in the manufacture of semiconductor devices to the manufacture of display devices as they are. For example, in order to convert to a high-resolution exposure device with a high NA (numerical aperture), a large investment must be made, and the price of the display device cannot be matched. Moreover, the change of the exposure wavelength (using a short wavelength such as ArF excimer laser) is disadvantageous in that considerable investment is still required. That is, the pursuit of miniaturization of patterns that were not available before, and on the other hand, the cost and efficiency that cannot compromise the existing advantages has become a problem for the mask used in the manufacture of display devices. According to the research of 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 later, and there is room for further improvement. There are the following elements (1) to (3) for the desired performance of the photomask. (1) Depth of focus (DOF) In the case where defocus occurs during exposure, it is ideal that the value of the depth of focus (DOF) for changing the CD within a specific range (for example, within ±10%) relative to the target CD is high. If the value of DOF is high, it is not easily affected by the flatness of the transferred body, and the pattern transfer is performed stably. Here, the so-called CD is the abbreviation of Critical Dimension and means the pattern width. The size of the photomask for display device manufacturing is larger than that for semiconductor device manufacturing, and the transfer target (display substrate, etc.) is also large in size. It is difficult to achieve perfect flatness with either of them, so the DOF is improved The value of the mask is of great significance. (2) Mask Error Enhancement Factor (MEEF: Mask Error Enhancement Factor) It 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 finer the pattern, the easier it is for the CD error on the mask to expand on the transferred body, but by suppressing it as much as possible to reduce the MEEF, the CD accuracy of the pattern formed on the transferred body can be improved . As the specifications of display devices evolve, the pattern is required to be miniaturized, and it is necessary to have a mask with a pattern close to the resolution limit of the exposure device. This is also true for the mask used in the manufacture of display devices. The possibility of focusing on MEEF in the future is high. (3)Eop It is the amount of exposure light necessary to form a pattern of the target size on the body to be transferred. In the manufacture of display devices, the size of the mask substrate is large (for example, the main surface is a quadrangular shape with a side of 300-2000 mm). Therefore, if a mask with a high Eop value is used, there is a need to reduce the speed of scanning exposure, which hinders production efficiency. Therefore, when manufacturing a display device, it is desirable to use a mask that can lower the value of Eop. According to the research of the present inventor, it is known that the improvement effect of DOF is obtained in the halftone type phase shift mask shown in FIG. 11, and on the other hand, it is desired to further improve the Eop and MEEF. Specifically, it can be seen that if the above-mentioned halftone type phase shift mask is used, the necessary amount of light (Dose) increases due to the loss of light intensity, so Eop is greatly increased, and the MEEF tends to increase along with this. There are still problems with the mask used in the manufacture of display devices. Therefore, the object of the present invention is to provide a photomask that can achieve both excellent resolution and production efficiency under the exposure conditions used in the manufacture of display devices. [Technical means to solve the problem] (First aspect) The first aspect of the photomask 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 aforementioned transfer pattern is a hole pattern used to form holes on the transferred body, and the aforementioned transfer pattern includes: Expose the transparent portion of the transparent substrate with a diameter of W1 (μm); A light-shielding edge part with a width of R (μm) surrounding the aforementioned light-transmitting part; and The phase shift part surrounding the aforementioned light-shielding edge part; and The phase difference between the aforementioned phase shift portion and the aforementioned transparent portion with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees; In the light intensity distribution formed on the transferred body by the exposure light passing through the phase shifting part located on one side of the light-transmitting part, when from the boundary position of the phase shifting part and the light-shielding edge part toward the light-shielding edge When setting the distance from the minimum point B1 of the first valley to d1 (μm), and the distance from the minimum point B2 of the second valley to d2 (μm), (d1-0.5×W1)≦R≦(d2-0.5×W1). (2nd aspect) The photomask of the second aspect of the present invention is characterized in that it is a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The aforementioned transfer pattern is a hole pattern used to form holes on the transferred body, and the aforementioned transfer pattern includes: Expose the transparent portion of the transparent substrate with a diameter of W1 (μm); A light-shielding edge part with a width of R (μm) surrounding the aforementioned light-transmitting part; and The phase shift part surrounding the aforementioned light-shielding edge part; and The phase difference between the aforementioned phase shift portion and the aforementioned transparent portion with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees; In the light intensity distribution formed on the transferred body by the exposure light passing through the phase shifting part located on one side of the light-transmitting part, when from the boundary position of the phase shifting part and the light-shielding edge part toward the light-shielding edge On the side of the first peak, out of the two points representing 1/2 of the light intensity of the maximum point P of the first peak, the point on the inclined part of the first peak that is close to the light-shielding edge is set to Q1, which will be located far away from the When the point of the inclined part on the side of the light-shielding edge is set as Q2, the distance from the aforementioned boundary position to Q1 is set as d3, and the distance from the aforementioned boundary position to Q2 is set as d4, (d3-0.5×W1)≦R≦(d4-0.5×W1). (3rd aspect) The third aspect of the present invention is the mask of the above-mentioned first aspect or second aspect, wherein The aforementioned transfer pattern is a hole pattern used to form holes with a diameter of W2 (W2≦W1) on the aforementioned body. (4th aspect) The fourth aspect of the present invention is the photomask of any one of the above-mentioned first to third aspects, wherein The phase shift part has a transmittance of 2-10% with respect to the light of the aforementioned representative wavelength. (5th aspect) The fifth aspect of the present invention is the photomask of any one of the above-mentioned first to fourth aspects, which is used for the use of a numerical aperture (NA) of 0.08 or more but less than 0.20, and has an i-line, h-line , Or the equal-magnification projection exposure device of the light source for g-line exposure exposes the aforementioned transfer pattern, and forms a hole with a diameter W2 of 0.8-3.0 (μm) on the transferred body. (6th aspect) A method for manufacturing a display device includes the following steps: The step of preparing the mask of any one of the first to fourth aspects above; and Use an equal-magnification projection exposure device with a numerical aperture (NA) of 0.08 to 0.20 and a light source for exposure including i-line, h-line, or g-line to expose the aforementioned transfer pattern, and on the transfer object The step of forming a hole with a diameter W2 of 0.8-3.0 (μm). [Effects of Invention] According to the present invention, it is possible to provide a photomask that can balance excellent resolution and production efficiency under the exposure conditions used in the manufacture of the display device.

Figure 1(a) is a cross-sectional view showing the halftone phase shift mask of the previous type, and Figure 1(b) shows the light passing through the phase shift part on one side of the transparent part in Figure 1(a) Graph of amplitude. In addition, FIG. 1(b) shows the amplitude of light passing through the phase shift portion 104 located on the left side of the light transmitting portion 103. It shows that the light passing through the phase shift part 104 located on the right side of the light-transmitting part 103 forms a transmitted light amplitude that is bilaterally symmetric with respect to the center of the light-transmitting part 103 and the transmitted light amplitude of Figure 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 transmitted phase shifting portion 104 reaches the left boundary of the light-transmitting portion 103 to the vicinity of the center on the transferred body The light of the corresponding area becomes (-) phase. Furthermore, this light interferes with the light of the (+) phase transmitted through the light transmitting portion 103. Therefore, the intensity of the light passing through the light transmitting portion 103 is relatively weakened. That is, due to the interference of the light of the (+) phase and the light of the (-) phase, the intensity of the light that passes through the light-transmitting portion 103 and reaches the body to be transferred is reduced. 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 shift part 104 is closer to the light-transmitting part 103 (right side in the figure) from the above-mentioned boundary position, and its phase changes to the (+) side, and forms a point with the maximum value of the light amplitude peak. Therefore, the inventors studied the possibility of improving the effect of Eop and MEEF by increasing the light intensity instead of using the transmitted light of the (+) phase forming the peak to suppress the above-mentioned reduction in light intensity. Sex. Fig. 2 is a diagram illustrating a study conducted on a method for converting the phase of light to the peak on the (+) side in the above Fig. 1(b) to be located at the position corresponding to the light-transmitting portion on the transferred body. Here, the light-shielding edge 105 is formed by the light-shielding film 106 near the edge on the light-transmitting part 103 side of the phase shift part 104. If the light shielding edge portion 105 is formed as described above, the portion of the phase shift film 101 covered by the light shield 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 the case where the light-shielding edge portion 105 is not formed. This means to shift the amplitude curve of the light of the phase shifter 104 to the left. Thereby, the part of the amplitude curve of the light passing through the phase shifting part 104 whose phase is transformed into the peak on the (+) side is shifted to the left. Therefore, the vicinity of the maximum value point of the amplitude curve forming the peak can be located within the width dimension of the light-transmitting portion 103 (preferably the center of the light-transmitting portion 103 or its vicinity). In this way, the exposure light can be used more effectively. The present invention was completed based on the findings of the inventors as described above. <The structure of the mask of the embodiment> Fig. 3 shows an example of the configuration of the photomask of the embodiment of the present invention, Fig. 3(a) is a schematic plan view, and Fig. 3(b) is a schematic cross-sectional view at position A-A in Fig. 3(a). The photomask shown in the figure is a photomask for manufacturing a display device having a pattern for transfer on a transparent substrate 10. The transfer pattern is a hole pattern used to form holes on the transferred body. It has a light-transmitting portion 11 with a diameter of W1 (μm) exposing the transparent substrate 10, and a width of R (μm) surrounding the light-transmitting portion 11 ) The light-shielding edge portion 12 and the phase shift 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 (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 "" 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 can be Cr or its compound (oxide, nitride, carbide, oxynitride, or carbon oxynitride), or can be a metal compound containing Mo, W, Ta, and Ti. The metal compound may be a metal silicide or the above-mentioned compound of the silicide. In addition, the material of the light-shielding film 15 can be wet-etched, and preferably is a material having etching selectivity with respect to the material of the phase shift film 14 (described later). In addition, the light-shielding film 15 and the phase shift film 14 may be those having a reflection control layer that controls the reflection of light provided on the front side and/or the back side. The phase shift part 13 is a phase shift film 14 formed on the transparent substrate 10. The phase shift film 14 may be Cr or its compound (oxide, nitride, carbide, oxynitride, or carbon oxynitride), or may be a metal compound containing 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, or The material of oxynitride is formed, and it can also be the above-mentioned compound of Si. In addition, the material of the phase shift film 14 is preferably a material that can be wet-etched. In addition, in the photomask of FIG. 3, in order to perform wet etching, it is preferable that no deep side etching is generated near the interface between the light-transmitting portion side of the phase shift film 14 and 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 way that even if side etching occurs, its width does not exceed the film thickness of the phase shift film 14. Here, the phase difference φ1 between the phase shift portion 13 and the light transmitting portion 11 with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees. The term "approximately 180 degrees" means 120 to 240 degrees. The above-mentioned 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 width of i-line, h-line, and g-line. The light-shielding edge portion 12 is formed on the transparent substrate 10 (the phase shift film 14 in FIG. 3). The light-shielding film 15 is formed on the transparent substrate 10 (the phase shift film 14 in FIG. 3). OD≧3) of the film. Moreover, the phase shift part 13 preferably has a transmittance T1 (%) of 2-10% with respect to the light of the representative wavelength of the exposure light. The above-mentioned transmittance T1 is more preferably 3-8%, and particularly preferably 3<T1<6. When the above-mentioned transmittance T1 is too high, an unfavorable layer that damages the remaining film thickness is likely to occur in the resist pattern formed on the to-be-transferred body, and if the above-mentioned transmittance T1 is too low, it is difficult to obtain the opposite described below. Contribution to the transmitted light intensity curve of the phase shift. In addition, the transmittance T1 here is set as the transmittance of light of the above-mentioned representative wavelength based on the transmittance of the transparent substrate 10 (100%). In addition, light including any one of i-line, h-line, and g-line, or broad-wavelength light including all of i-line, h-line, and g-line may be used as light for exposure. 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 top view shape of the light transmitting portion 11 is a square, and the diameter W1 at this time is the size of one side of the square. When the plan view shape of the light-transmitting portion 11 is a rectangle, the size of the long side is set as the diameter W1. The shape of the light-transmitting portion 11 is preferably a quadrangular shape, and more preferably a square shape. If the diameter W1 is too large, it will sufficiently exceed the resolution limit size of the exposure device for the display device. Therefore, a sufficient resolution can be obtained by the previous mask, and the improvement effect of the present invention will not be significantly produced. On the other hand, if the diameter W1 is too small, it is not easy to stably obtain the correct CD during mask manufacturing. More preferably, 0.8≦W1≦3.5. Moreover, when further miniaturization is desired, 1.0<W1<3.0, and further 1.2<W1<2.5 can be set. When a hole with a diameter of W2 (μm) is formed on the transfer target body using the transfer pattern provided in the photomask of this embodiment, it is preferably 0.8≦W2≦3.0. The diameter W2 of the hole formed on the body to be transferred refers to the length of the largest part of the distance between 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. Also, if β (μm) is set as the mask deviation value (W1-W2), β>0 (μm), the mask deviation value β (μm) is preferably 0.2≦β≦1.0, more preferably 0.2≦ β≦0.8. Fig. 4(a) is a plan view showing a part of the transfer pattern (the part enclosed by a dotted line in Fig. 3) when the width of the light-shielding edge portion is set to be relatively narrow in the mask of the embodiment of the present invention, Fig. 4 (b) is a diagram showing the light intensity distribution formed on the transferred body by the transmitted light passing through the phase shift part on the left side of the mask at this time. 5(a) is a plan view showing a part of the transfer pattern (the part enclosed by a dotted line in FIG. 3) when the width of the light-shielding edge is set to be relatively wide in the mask of the embodiment of the present invention, Fig. 5(b) is a diagram showing the light intensity distribution formed on the transferred body by the transmitted light passing through the phase shift part on the left side of the mask at this time. As shown in Fig. 4(b) and Fig. 5(b), if the light passing through the phase shift part 13 located on one side of the light-transmitting part 11 (the left side in the figure) is drawn by a curve, it is formed on the body to be transferred. 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 side (the right side in the figure). The first peak corresponds to the peak of the part whose phase is shifted to the (+) side in the light amplitude curve shown in FIG. 1 above. Here, when the distance from the above-mentioned boundary position to the minimum point B1 (Figure 4) of the first valley is set to d1 (μm), the distance to the minimum point B2 (Figure 5) of 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 of the above formula (1), and FIG. 5 shows the upper limit of the width R. If the width R of the light-shielding edge portion 12 is set to satisfy the above formula (1), the transmitted light of the (+) phase of the transmitted light of the phase shift portion 13 can be positioned at the center of the light-transmitting portion 11. That is, at least a part of the (+) phase part of the transmitted light passing through the phase shift portion 13 and the (+) phase transmitted light passing through the light transmitting portion 11 reach the body to be transferred, thereby improving its The effect of the peak light intensity. Next, regarding the pattern structure for making more of the (+) phase of the transmitted light transmitted through the phase shifting portion 13 reach the object to be transferred, we will use FIGS. 6 and 7 to study. Fig. 6(a) is a plan view showing a part of the transfer pattern (the part enclosed by a dotted line in Fig. 3) when the width of the light-shielding edge is set to be relatively narrow in the mask of the embodiment of the present invention, Fig. 6 (b) is a diagram showing the light intensity distribution formed on the transferred body by the transmitted light passing through the phase shift part on the left side of the mask at this time. 7(a) is a plan view showing a part of the transfer pattern (the part enclosed 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 of the embodiment of the present invention, Fig. 7(b) is a diagram showing the light intensity distribution formed on the transferred body by the transmitted light passing through the phase shift portion on the left side of the mask at this time. As shown in Fig. 6(b) and Fig. 7(b), if the light passing through the phase shift part 13 located on one side of the light-transmitting part 11 (the left side in the figure) is drawn by a curve, it is formed on the transferred body The light intensity distribution is the same as the above, the first valley, the first peak, and the second valley appear from the boundary position of the phase shifting portion 13 and the light shielding edge portion 12 toward the light shielding edge portion 12 side (right side in the figure). At this time, out of the two points representing 1/2 of the light intensity of the maximum point P of the first peak, the point of the inclined part located on the side of the first peak near the light-shielding edge part 12 (left side in the figure) is set as Q1, set the point of the inclined portion on the side away from the light-shielding edge portion 12 (right side in the figure) as Q2, set the distance from the above-mentioned boundary position to Q1 as d3 (Figure 6), and set the distance from the above-mentioned 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 light-shielding edge portion 12 of the above formula (2), and FIG. 7 shows the upper limit. If the width R of the light-shielding edge portion 12 is set in a manner that satisfies the above formula (2), the (+) phase of the transmitted light of the phase shift portion 13 and the portion whose light intensity is greater (about half of the upper portion) can be located The center of the transparent portion 11. That is, the portion of the (+) phase close to the peak (maximum point P) of the transmitted light passing through the phase shift portion 13 can be reliably located near the center within the size of the light transmitting portion 11 and reach the transferred body , And get the effect of increasing the peak light intensity more effectively. According to the mask of this embodiment, it is possible to shift the position of the peak of the (+) phase in the amplitude curve of the light passing through the phase shift part 13 so that more of the peak of the (+) phase is located in the light-transmitting part Within the size of 11. In this way, the exposure light can be used more effectively. As a result, it is possible to achieve both excellent resolution and production efficiency under the exposure conditions used in the manufacture of the display device. Specifically, for example, under exposure conditions with a numerical aperture (NA) of 0.08≦NA≦0.20 and a correlation factor (σ) of 0.4≦σ≦0.9, a mask with excellent MEEF and Eop can be realized. The numerical aperture (NA) is more preferably 0.08<NA<0.20, and more preferably 0.10<NA<0.15. On the other hand, the correlation factor (σ) is more preferably 0.4<σ<0.7, and more preferably 0.4<σ<0.6. The transfer pattern of the photomask of this embodiment is used to form holes on the transferred body, including: a light-transmitting portion with a diameter of W1 (μm) exposed on the transparent substrate, and a width surrounding the light-transmitting portion: R (μm) the light-shielding edge and the phase shift part surrounding the light-shielding edge. In other words, the improvement effect of MEEF and Eop can be obtained without including other structures for forming the hole (auxiliary patterns for auxiliary transferability, etc.). The photomask of the present embodiment is suitably used as a photomask for forming isolated holes in a transfer target body, or can also be used as a photomask for forming dense holes in a transfer target body. The so-called dense holes means that a plurality of hole patterns are regularly arranged and produce optical effects with each other. The present invention includes a method of manufacturing a display device in which the above-mentioned transfer pattern is transferred to a transfer target body by exposing the photomask of this embodiment with an exposure device. In the manufacturing method of the display device of the present invention, the photomask of this embodiment is first prepared. Next, the above-mentioned transfer pattern is exposed using an exposure device, and a hole having a diameter W2 of 0.8 to 3.0 (μm) is formed in the transferred body. For exposure, an exposure device with a numerical aperture (NA) of 0.08 to 0.20 and a light source for exposure including i-line, h-line, or g-line is used. Moreover, for exposure, it is preferable to use an exposure device that performs equal-magnification projection exposure, and the numerical aperture (NA) of the optical system is 0.08-0.20 (correlation factor (σ) is 0.4-0.9) and is included in the exposure light An exposure device that includes a light source for exposure of at least one of i-line, h-line, and g-line. When a single wavelength is used for exposure light, it is preferable to use i-line. In addition, wide-wavelength light including all i-line, h-line, and g-line can be used as exposure light. Although the light source of the exposure device used can use oblique illumination (ring illumination, etc.) in addition to the vertical incident component, the excellent effects of the present invention can be obtained by using normal illumination containing the vertical incident component without using oblique illumination. . The photomask of the embodiment of the present invention can be manufactured, for example, after preparing a blank photomask having a structure in which the phase shift film 14 and the light shielding film 15 are sequentially laminated on the transparent substrate 10, and then the two films are patterned separately. What is necessary is just to apply a well-known film formation method, such as a sputtering method, to the film formation of the phase shift film 14 and the light-shielding film 15. In addition, when manufacturing the photomask, a well-known photoresist can be used in the photolithography step, and a laser drawing device or the like can be used. When manufacturing the mask of FIG. 3, it is ideal to precisely control the width R of the light-shielding edge 12. This is because it affects the contour of the spatial image formed on the transferred body during exposure. Preferably, when the photomask of FIG. 3 is manufactured, drawing is performed with respect to the above-mentioned blank photomask formed with a resist film. First, the light-shielding film 15 is etched to form the light-shielding edge portion 12 (delineation of the light-shielding edge portion), Next, a resist film is formed again, and the phase shift film 14 is drawn and etched to form the light-transmitting portion 11. Next, an optical simulation performed using the photomask of the embodiment of the present invention will be described. In the optical simulation, a photomask having the same transfer pattern (hole pattern) as shown in FIG. 3 was used. At this time, when the diameter W1 of the light-transmitting portion 11 is set to 2 μm, and the hole with a diameter W2 of 1.5 μm is transferred to the transfer object (the mask deviation value β=0.5 μm), according to the light-shielding edge portion 12 The dimension of width R verifies how the optical performance of MEEF and Eop changes. In addition, the transmittance of the exposure light of the phase shift part 13 is set to 5.2% for the i-line. The optical conditions used in the simulation are as follows. The optical system coefficient value of the exposure device has an aperture NA of 0.1, and the correlation factor σ is 0.5. In addition, a light source (broad-wavelength light source) including all i-line, h-line, and g-line is used as a light source for exposure, and the intensity ratio is set to g:h:i=1:1:1. FIG. 8 is a graph showing the simulation result of the MEEF value for the change in the width of the shading edge, and FIG. 9 is a graph showing the simulation result of the Eop value for the change in the width of the shading edge. In FIGS. 8 and 9, the Rim Size (μm) on the horizontal axis represents 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 is equivalent to the case of using the same previous type halftone type phase shift mask as in FIG. 11. According to Fig. 8, the value of MEEF changes due to the change of the width R of the light-shielding edge 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. The value of MEEF at this time is lower than 5.25, which is a value lower than half of the previous type halftone phase shift mask with the light-transmitting part (hole pattern) of the same diameter W1. Furthermore, according to FIG. 9, it can be seen that the Eop of the mask of this embodiment is significantly reduced compared to the previous halftone type phase shift mask. In particular, the width R of the light-shielding edge 12 is in the range of 0.5 to 2.0 μm. The dose required for exposure is reduced 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%. Figure 10 is a spatial image (that is, the light intensity distribution of transmitted light) formed on the transferred body when the photomask (edge width R=1.0 μm) of this embodiment used in the above simulation is exposed by an exposure device A diagram for comparison with a spatial image formed by a binary mask (Binary) with a hole pattern of the same diameter, and a spatial image formed by a previous halftone phase shift mask (Att. PSM). According to the above Figure 10, it can be seen that the spatial image formed by the mask of this embodiment has a higher peak than the spatial images formed by other masks, has a steeper slope (close to vertical), and is advantageous for forming fine holes. The outline.

10: Transparent substrate 11: Translucent part 12: Shading edge 13: Phase shift part 14: Phase shift film 15: Shading film 100: Transparent substrate 101: Phase shift film 103: Transmitting part 104: Phase shift part 105: shading edge 106: shading film B1: minimum point B2: minimum point d1: distance d2: distance d3: distance d4: distance P: Maximum point Q1: point Q2: point R: width/edge width W1: diameter

Figure 1(a) shows the cross-section of the previous halftone type phase shift mask; Figure 1(b) shows the amplitude of the light passing through the phase shift part on the left side of the transparent part in Figure 1(a) Figure. Figures 2(a) and 2(b) illustrate the position of the light-transmitting part corresponding to the light-transmitting part of the part used to convert the phase of the light in Figure 1(b) to the peak on the (+) side Diagram of the method of research. Fig. 3 shows an example of the configuration of the mask according to the embodiment of the present invention; Fig. 3(a) is a schematic plan view; Fig. 3(b) is a schematic cross-sectional view at the position A-A of Fig. 3(a). Fig. 4(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 of the embodiment of the present invention; Fig. 4(b) is a plan view showing the transmission pattern at this time A diagram of the light intensity distribution formed by the transmitted light of the phase shift part on the left on the body to be transferred (Part 1). Fig. 5(a) is a plan view of a part of the transfer pattern when the width of the light-shielding edge is set to be wide in the mask of the embodiment of the present invention; Fig. 5(b) shows the left side of the transparent mask at this time A diagram of the light intensity distribution formed by the transmitted light of the phase shift portion on the transfer body (Part 1). Fig. 6(a) is a plan view showing a part of the transfer pattern when the width of the light-shielding edge is set to be narrow in the mask of the embodiment of the present invention; Fig. 6(b) is a plan view showing the transmission pattern at this time A diagram of the light intensity distribution of the transmitted light in the phase shift part on the left on the transfer body (Part 2). Fig. 7(a) is a plan view of a part of the transfer pattern when the width of the light-shielding edge is set to be wide in the mask of the embodiment of the present invention; Fig. 7(b) shows the left side of the transparent mask at this time A diagram of the light intensity distribution formed by the transmitted light of the phase shift portion on the transfer body (Part 2). Figure 8 is a graph showing the simulation results for MEEF. Figure 9 is a graph showing the simulation results for Eop. Figure 10 shows the optical image (that is, the light intensity distribution of the transmitted light) formed on the transferred body when the mask (edge width R=1.0 μm) of this embodiment is exposed by the exposure device and has the same diameter The optical image formed by the binary mask (Binary) of the hole pattern is compared with the optical image formed by the previous halftone type phase shift mask (Att.PSM). Fig. 11 shows an example of the structure of a previous halftone type phase shift mask; Fig. 11(a) is a schematic plan view; Fig. 11(b) is a schematic cross-sectional view at the position B-B in Fig. 11(a).

10: Transparent substrate

11: Translucent part

12: Shading edge

13: Phase shift part

14: Phase shift film

15: Shading film

R: width/edge width

W1: diameter

Claims (12)

A method for manufacturing a photomask, characterized in that it is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The aforementioned transfer pattern is a hole pattern used to form holes on the transferred body, and the aforementioned transfer pattern includes: Expose the transparent portion of the transparent substrate with a diameter of W1 (μm); A light-shielding edge part with a width of R (μm) surrounding the aforementioned light-transmitting part; and The phase shift part surrounding the aforementioned light-shielding edge part; and The phase difference between the aforementioned phase shift portion and the aforementioned transparent portion with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees; In the light intensity distribution formed on the transferred body by the exposed light passing through the phase shifting part located on one side of the light-transmitting part, when the boundary position from the phase shifting part and the light-shielding edge part is directed toward the The distance from the minimum point B1 of the first valley on the side of the light-shielding edge is set as d1 (μm), and the distance from the minimum point B2 of the second valley on the side of the light-shielding edge from the aforementioned boundary position is set to d2( μm), set the width R of the aforementioned light-shielding edge to satisfy the following formula, (d1-0.5×W1)≦R≦(d2-0.5×W1). A method for manufacturing a photomask, characterized in that it is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The aforementioned transfer pattern is a hole pattern used to form holes on the transferred body, and the aforementioned transfer pattern includes: Expose the transparent portion of the transparent substrate with a diameter of W1 (μm); A light-shielding edge part with a width of R (μm) surrounding the aforementioned light-transmitting part; and The phase shift part surrounding the aforementioned light-shielding edge part; and The phase difference between the aforementioned phase shift portion and the aforementioned transparent portion with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees; In the light intensity distribution formed on the transferred body by the exposed light passing through the phase shifting part located on one side of the light transmitting part, when the boundary position from the phase shifting part and the light shielding edge part is toward the Among the two points of 1/2 of the light intensity of the maximum point P of the first peak on the side of the light-shielding edge, the point of the inclined part on the side of the first peak that is close to the light-shielding edge is set to Q1, which will be located far away The point of the inclined part on the side of the light-shielding edge is set as Q2, and the distance from the aforementioned boundary position to Q1 is set as d3, and the distance from the aforementioned boundary position to Q2 is set as d4, the following formula is satisfied The width R of the aforementioned light-shielding edge, (d3-0.5×W1)≦R≦(d4-0.5×W1). The method for manufacturing a photomask according to claim 1 or 2, wherein for the transfer pattern without the light-shielding edge portion, the amount of exposure light Eop necessary to obtain a pattern of the target size on the transfer body is reduced. Such as the manufacturing method of the photomask of claim 1 or 2, wherein the diameter W1 (μm) of the aforementioned light-transmitting part satisfies: 0.8≦W1≦4.0. For example, the manufacturing method of the photomask of claim 1 or 2, which includes the following steps: Prepare a blank mask with a phase shift film and a light-shielding film laminated on the aforementioned transparent substrate; Etching the light-shielding film to form the light-shielding edge; and The phase shift film is etched to form the light transmitting portion. The method for manufacturing a photomask of claim 5, wherein the wavelength dependence of the phase shift amount of the phase shift film is within 40 degrees with respect to the variation width of the i-line, h-line, and g-line. The method for manufacturing a photomask according to claim 1 or 2, wherein the transfer pattern is used to form a hole pattern with a diameter of W2 (W2≦W1) on the transfer target body. According to claim 1 or 2, the method for manufacturing a photomask, wherein the phase shift portion has a transmittance of 2-10% with respect to the light of the representative wavelength. For example, the manufacturing method of the photomask of claim 1 or 2, which is used for equal-magnification projection exposure using a light source with a numerical aperture (NA) of 0.08～0.20 and exposure including i-line, h-line, or g-line The device exposes the aforementioned transfer pattern to form a hole having a diameter W2 of 0.8 to 3.0 (μm) in the transfer target body. A method for manufacturing a display device includes the following steps: Preparation steps for preparing the mask manufactured by the manufacturing method of claim 1 or 2; and Use an equal-magnification projection exposure device with a numerical aperture (NA) of 0.08 to 0.20 and a light source for exposure including i-line, h-line, or g-line to expose the aforementioned transfer pattern, and on the object to be transferred The step of forming a hole with a diameter W2 of 0.8-3.0 (μm). A method for manufacturing a photomask, characterized in that it is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The aforementioned transfer pattern is a hole pattern used to form holes on the transferred body, and the aforementioned transfer pattern includes: Expose the transparent portion of the transparent substrate with a diameter of W1 (μm); A light-shielding edge part with a width of R (μm) surrounding the aforementioned light-transmitting part; and The phase shift part surrounding the aforementioned light-shielding edge part; and The phase difference between the aforementioned phase shift portion and the aforementioned transparent portion with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees; In the light amplitude curve formed on the transferred body by the exposure light passing through the phase shift part located on one side of the light transmitting part, the light amplitude curve having the peak of the (+) side phase is formed by the maximum The value point is located within the width dimension of the light-transmitting part. For the transfer pattern that does not have the light-shielding edge part, the amount of exposure light necessary to obtain a pattern of the target size on the transfer body is reduced. A method for manufacturing a photomask, characterized in that it is a method for manufacturing a photomask for manufacturing a display device with a pattern for transfer on a transparent substrate; and The aforementioned transfer pattern is a hole pattern used to form holes on the transferred body, and the aforementioned transfer pattern includes: Expose the transparent portion of the transparent substrate with a diameter of W1 (μm); A light-shielding edge part with a width of R (μm) surrounding the aforementioned light-transmitting part; and The phase shift part surrounding the aforementioned light-shielding edge part; and The phase difference between the aforementioned phase shift portion and the aforementioned transparent portion with respect to the light of the representative wavelength of the exposure light is approximately 180 degrees; In the light amplitude curve formed on the transferred body by the exposure light passing through the phase shift part located on one side of the light-transmitting part, the half of the upper part of the peak with the (+) side phase is located in the light-transmitting part Within the size of the part, increase the peak light intensity.

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