Photomask, method of manufacturing display device

Abstract

The present application provides a photomask, a manufacturing method of a display device. The photomask has a transfer pattern formed on a transparent substrate, the transfer pattern includes: a main pattern composed of a light transmission part, the diameter is W1; an auxiliary pattern configured in the vicinity of the main pattern, not imaged by an exposure device, with a width d; and a light shielding part constituting a region other than the main pattern and the auxiliary pattern, the light shielding part is formed by at least forming a light shielding film on the transparent substrate, the auxiliary pattern surrounds the periphery of the main pattern through the light shielding part, and is composed of a phase shift part formed by forming a semi-light transmission film on the transparent substrate, the semi-light transmission film has a phase characteristic of shifting the light of a representative wavelength of exposure light in a range of substantially 180 degrees, and has a transmittance T for the light of the representative wavelength, the transmittance of a part of the auxiliary pattern is lower than that of the other regions of the auxiliary pattern, and the photomask is implemented with an expansion correction of expanding the width of the main pattern.

Description

[0001] The present application is a divisional application of the patent application for invention with the title of "Photomask and its correction method, manufacturing method, manufacturing method of display device", the application date of September 11, 2018, and the application number of 201811056319.0. TECHNICAL FIELD

[0002] The present application relates to a correction (repair) method of a photomask which is advantageous for manufacturing a display device represented by a liquid crystal display, an organic EL display, a photomask obtained by the correction method, a manufacturing method of a photomask, and a manufacturing method of a display device. BACKGROUND

[0003] Patent Literature 1 describes a photomask including a transfer pattern formed by patterning a semi-transmissive film and a low-transmissive film formed on a transparent substrate, the semi-transmissive film deflecting light of a representative wavelength in a wavelength range of i-line to g-line by substantially 180 degrees and having a transmittance T(%) for the light of the representative wavelength, and the low-transmissive film having a transmittance T2(%) for the light of the representative wavelength which is lower than the transmittance T(%) of the semi-transmissive film, the transfer pattern including a main pattern composed of a transmissive portion of the transparent substrate, having a diameter of W1(μm), an auxiliary pattern disposed in the vicinity of the main pattern, composed of a semi-transmissive portion of the transparent substrate on which the semi-transmissive film is formed, having a width of d(μm), and a low-transmissive portion disposed in a region of the transfer pattern other than a region in which the main pattern and the auxiliary pattern are formed, having at least the low-transmissive film formed on the transparent substrate.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1 Japanese Patent Application Publication No. 2016-024264 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] Now, in a display device including a liquid crystal display device, an EL display device, and the like, it is required to be brighter and save power, and at the same time, it is required to improve display performance such as high fineness, high-speed display, and wide viewing angle.

[0009] For example, in the case of a thin film transistor (TFT) used in the above-described display device, among a plurality of patterns constituting the TFT, if a contact hole formed in an interlayer insulating film does not have a function of reliably connecting a pattern of an upper layer and a pattern of a lower layer, accurate operation cannot be ensured. On the other hand, for example, in order to realize a display device that is bright and power-saving by greatly expanding the aperture ratio of a liquid crystal display device, it is required that the diameter of a contact hole be sufficiently small, and in addition to the high density of the display device, it is also required that the diameter of a hole pattern be miniaturized (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 is required, and further, a hole pattern having a diameter of 2.0 μm or less is required, and specifically, forming a pattern having a diameter of 0.8 to 1.8 μm is also a problem.

[0010] In the field of a photomask for manufacturing a semiconductor device (LSI) in which the degree of integration is high and the miniaturization of a pattern is significantly improved, compared with a display device, in order to obtain higher resolution, there is a process of applying an optical system having a larger numerical aperture NA (for example, more than 0.2) in an exposure device and promoting the shortening of the wavelength of light for exposure. As a result, in this field, an excimer laser of KrF, ArF (single wavelength of 248 nm, 193 nm, respectively) is mostly used.

[0011] On the other hand, in the field of photolithography for manufacturing a display device, in order to improve resolution, generally, the above-described method is not applied. For example, the NA (numerical aperture) of the optical system of an exposure device used in this field is 0.08 to 0.15. In addition, as a light source for exposure, i-line, h-line, or g-line is mostly used, and by using a wide wavelength range light source mainly including these, the amount of light for irradiating a large area (for example, a quadrangle having one side of 300 to 2000 mm) is obtained, and thus, there is a tendency to place importance on production efficiency and cost.

[0012] However, in the manufacturing of a display device, as described above, the miniaturization of a pattern is required to be higher. In this case, in the case where the technology for manufacturing a semiconductor device is directly applied to the manufacturing of a display device, there are several problems. For example, when converted to an exposure device having high resolution with high NA (numerical aperture), a larger equipment investment is required, and matching with the price of a display device cannot be obtained. In addition, regarding the change of the wavelength of exposure (utilization of a short wavelength such as an ArF excimer laser in a single wavelength manner), if applied to a display device having a large area, in addition to the decrease in production efficiency, a considerable equipment investment is still required, and there is a defect in this point. That is, while pursuing the miniaturization of a pattern that has not been pursued in the past, the cost and efficiency, which are the advantages of the present, cannot be lost, and this is a problem point of a photomask for manufacturing a display device.

[0013] Further, in Patent Literature 1, there is described a photomask provided with a main pattern constituting a light-transmitting portion, an auxiliary pattern constituted by a phase shift portion disposed in the vicinity thereof, and a low light-transmitting portion formed in a region other than these. This photomask can control the mutual interference of exposure light transmitted through both the main pattern and the auxiliary pattern, and greatly improve the spatial image of transmitted light. Further, this photomask can be advantageous in forming a stable and fine isolated hole pattern or the like on a transfer target such as a display panel substrate.

[0014] As described in Patent Literature 1, in the case of an appropriately designed auxiliary pattern in which the main pattern is not directly imaged on the transfer target, the transferability of the main pattern can be effectively improved. However, the auxiliary pattern is a fine pattern designed with delicacy, and countermeasures in the case of defects occurring in the position thereof become a problem to be solved.

[0015] Generally, in the manufacturing process of a photomask, it is extremely difficult to make the occurrence of pattern defects zero. For example, it is practically unavoidable that residual defects (also referred to as black defects) caused by the mixing of foreign matter (particles) or the like due to the residual of an unnecessary film, or peeling defects (also referred to as white defects) caused by the peeling of a necessary film occur. Assuming such a case, a process of detecting these defects by inspection and correcting (repairing) the defects by a correction device is provided. As a method of correction, generally, for white defects, a correction film is stacked, and for black defects, the residual portion is removed by irradiation of an energy line, and a correction film is stacked as necessary. White defects and black defects can be corrected mainly by a FIB (Focused Ion Beam) device or a laser CVD (Chemical Vapor Deposition) device.

[0016] For example, in a laser CVD device, a case in which a correction film is formed with respect to a defect generated in a photomask will be described. First, a defect is detected by an inspection device, and an object portion in which formation of a correction film is performed is determined. The object of formation of a correction film is a white defect generated on a light-blocking film or a semi-light-transmitting film (hereinafter, referred to as a normal light-blocking film and a normal semi-light-transmitting film, respectively) of a transfer pattern possessed by a photomask, or a white defect formed by removing a black defect. With respect to this correction object portion, a local correction film (also referred to as a CVD film) is formed by a laser CVD method.

[0017] At this time, a raw material gas of a raw material constituting a correction film is supplied to the surface of a photomask, and a raw material gas environment is formed. As a raw material of a correction film, a metal carbonyl is preferably used. Specifically, chromium carbonyl (Cr(CO)6), molybdenum carbonyl (Mo(CO)6), tungsten carbonyl (W(CO)6), or the like can be exemplified. As a correction film of a photomask, chromium carbonyl having high chemical resistance is preferably used.

[0018] In the case where chromium carbonyl is used as a raw material for a repair film, for example, hexacarbonyl chromium (Cr(CO)6) is heated to sublimate, and the sublimated product is introduced into a repair target portion of a photomask together with a carrier gas (Ar gas or the like). A laser is irradiated into the raw material gas atmosphere, and the raw material gas is decomposed by the heat / light energy of the laser, and a product is accumulated in the repair target portion, thereby forming a repair film mainly made of chromium.

[0019] According to the research by the present inventors, the following problem was found. Even if the above method is used, depending on the shape, size, or kind of function of a pattern, the repair as described above cannot be performed uniformly.

[0020] For example, in the case where a CVD film is formed on a defect generated in a light shielding film, a repair film (hereinafter, also referred to as a complementary film) having sufficient light shielding properties is formed. On the other hand, a CVD film using a suitable material can obtain a desired light transmittance in a certain range by adjusting the film thickness. However, it is not necessarily easy to accumulate a uniform repair film having a desired transmittance (i.e., a desired film thickness) in a fine size at an accurate position. In addition, in the case where a defect is generated in a semi-transmissive film, it is more difficult to obtain a desired phase characteristic (a phase shift amount with respect to a wavelength included in exposure light) while forming a repair film having a film thickness for constituting a prescribed light transmittance. Therefore, there is a difficulty in the repair of a photomask having a phase shift portion.

[0021] That is, regarding the repair of a photomask having a phase shift portion or a photomask having a fine pattern (for example, having a size below a resolution limit), since the difficulty is high, it easily leads to a decrease in production efficiency, and in addition, it is not rare that a new defect having a size or optical properties different from a target value is generated in the process of repair.

[0022] Under such circumstances, in order to explore a method capable of performing appropriate defect repair even in the case where a defect is generated in a fine pattern exemplified in the photomask described in the above Patent Document 1, the present inventors have made intensive research.

[0023] Therefore, an object of the present application is to provide a photomask repair method and a repaired photomask obtained by the repair method, which efficiently repair a defect generated in a transfer pattern under stable conditions, and restore an optical function of the transfer pattern damaged by the defect, thereby achieving good transfer performance.

[0024] Means for solving the problem

[0025] The present application provides a photomask having a transfer pattern formed on a transparent substrate, the photomask being characterized in that the transfer pattern includes: a main pattern composed of a light-transmitting portion, having a diameter of W1 (μm); an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern, the light-blocking portion being formed by at least forming a light-blocking film on the transparent substrate, the auxiliary pattern surrounding a periphery of the main pattern through the light-blocking portion, and being composed of a phase shift portion formed by forming a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic that shifts a representative wavelength of exposure light by substantially 180 degrees, and having a transmittance T (%) for the representative wavelength of light, the amount of transmitted light of a part of the auxiliary pattern being lower than the amount of transmitted light of other regions of the auxiliary pattern, the photomask being subjected to expansion correction that expands the width of the main pattern.

[0026] In addition, the present application provides a photomask having a transfer pattern formed on a transparent substrate, the photomask being characterized in that the transfer pattern includes: a main pattern composed of a light-transmitting portion, having a diameter of W1 (μm); an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern, the light-blocking portion being formed by at least forming a light-blocking film on the transparent substrate, the auxiliary pattern surrounding a periphery of the main pattern through the light-blocking portion, and being composed of a phase shift portion formed by forming a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic that shifts a representative wavelength of exposure light by substantially 180 degrees, and having a transmittance T (%) for the representative wavelength of light, the amount of transmitted light of a part of the auxiliary pattern being lower than the amount of transmitted light of other regions of the auxiliary pattern, the transfer pattern including a normal transfer pattern and a corrected transfer pattern subjected to expansion correction that expands the width of the main pattern, the area of the main pattern of the corrected transfer pattern being larger than the area of the main pattern of the normal transfer pattern.

[0027] Further, the present application provides a photomask having a transfer pattern formed on a transparent substrate, the photomask being characterized in that the transfer pattern includes: a main pattern composed of a light-transmitting portion, having a diameter of W1 (μm); an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern, the light-blocking portion being formed by forming at least a light-blocking film on the transparent substrate, the auxiliary pattern surrounding a periphery of the main pattern through the light-blocking portion, and being composed of a phase shift portion formed by forming a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic that shifts a representative wavelength of exposure light by substantially 180 degrees, and having a transmittance T (%) for the representative wavelength of the exposure light, the amount of transmitted light of a part of the auxiliary pattern being lower than the amount of transmitted light of other regions of the auxiliary pattern, the transfer pattern including a normal transfer pattern and a corrected transfer pattern in which the width of the main pattern is expanded, an aspect ratio of the main pattern of the corrected transfer pattern being different from an aspect ratio of the main pattern of the normal transfer pattern.

[0028] Further, the present application provides a manufacturing method of a display device, the manufacturing method including a step of transferring the transfer pattern to a transfer body by exposing the photomask described above by an exposure device.

[0029] (First Embodiment)

[0030] The first embodiment of the present application is a correction method of a photomask having a transfer pattern formed on a transparent substrate,

[0031] The correction method of the photomask is characterized in that,

[0032] the transfer pattern includes:

[0033] a main pattern composed of a light-transmitting portion, having a diameter of W1 (μm);

[0034] an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and

[0035] a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern,

[0036] the light-blocking portion being formed by forming at least a light-blocking film on the transparent substrate,

[0037] the auxiliary pattern having a transmittance T (%) for a representative wavelength of exposure light, and surrounding a periphery of the main pattern through the light-blocking portion,

[0038] a phase difference between a transmittance of the light of the representative wavelength on the auxiliary pattern and a transmittance of the light of the representative wavelength on the main pattern is substantially 180 degrees,

[0039] When the white defect is generated in the auxiliary pattern, a complementary film correction of forming a complementary film having light shielding property made of a material different from the light shielding film is performed in the white defect portion.

[0040] (2nd Aspect)

[0041] The complementary film correction recovers at least a part of the optical performance of the transfer pattern which is degraded due to generation of the white defect.

[0042] The white defect is 1 / 8 or less of the area of the auxiliary pattern.

[0043] (3rd Aspect)

[0044] The complementary film correction recovers at least a part of the optical performance of the transfer pattern which is degraded due to generation of the white defect.

[0045] The complementary film correction recovers at least a part of the optical performance of the transfer pattern which is degraded due to generation of the white defect.

[0046] (4th Aspect)

[0047] The complementary film correction recovers at least a part of the optical performance of the transfer pattern which is degraded due to generation of the white defect.

[0048] The optical performance includes any of a peak height of a light intensity distribution formed on a transfer body by a transmittance of the transfer pattern, a focal depth, and an exposure latitude.

[0049] (5th Aspect)

[0050] The complementary film correction recovers at least a part of the optical performance of the transfer pattern which is degraded due to generation of the white defect.

[0051] The auxiliary pattern is formed by forming a semi-transmissive film on the transparent substrate, the semi-transmissive film having a transmittance T(%) for the light of the representative wavelength and having a phase characteristic of substantially shifting the light of the representative wavelength by 180 degrees.

[0052] (6th Aspect)

[0053] The 6th aspect of the present application is a complementary film correction method of a photomask having a transfer pattern formed on a transparent substrate,

[0054] The complementary film correction method of the photomask is characterized in that,

[0055] The transfer pattern includes:

[0056] a main pattern composed of a light-transmitting portion having a diameter of W1 (μm);

[0057] an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and

[0058] a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern,

[0059] the light-blocking portion is formed by at least forming a light-blocking film on the transparent substrate,

[0060] the auxiliary pattern has a transmittance T (%) for light of a representative wavelength of exposure light, and surrounds a periphery of the main pattern through the light-blocking portion,

[0061] a phase difference between a transmitted light of the representative wavelength of light on the auxiliary pattern and a transmitted light of the representative wavelength of light on the main pattern is substantially 180 degrees,

[0062] when a black defect is generated in the auxiliary pattern, expansion correction of expanding the width of the main pattern is performed.

[0063] (7th aspect)

[0064] the correction method of the photomask of the 7th aspect of the present application is based on the 6th aspect,

[0065] the expansion correction recovers at least a part of an optical performance of the transfer pattern which is degraded due to generation of the black defect.

[0066] (8th aspect)

[0067] the correction method of the photomask of the 8th aspect of the present application is based on the 7th aspect,

[0068] the optical performance includes any of a peak height of a light intensity distribution formed on a transfer body by a transmitted light of the transfer pattern, a depth of focus, and an exposure latitude.

[0069] (9th aspect)

[0070] the correction method of the photomask of the 9th aspect of the present application is based on any one of the 6th to 8th aspects,

[0071] the black defect exceeds 1 / 8 of an area of the auxiliary pattern.

[0072] (10th aspect)

[0073] the correction method of the photomask of the 10th aspect of the present application is based on any one of the 6th to 8th aspects,

[0074] The auxiliary pattern is formed by forming a semi-transmissive film on the transparent substrate, the semi-transmissive film having a transmittance T(%) for the representative wavelength light and having a phase characteristic of substantially shifting the representative wavelength light by 180 degrees.

[0075] (11th aspect)

[0076] The correction method of the photomask of the 11th aspect of the present application is based on any one of the 6th to 8th aspects,

[0077] The black defect is a black defect generated by forming a light-shielding complementary film on a white defect portion generated in the auxiliary pattern.

[0078] (12th aspect)

[0079] The correction method of the photomask of the 12th aspect of the present application is based on any one of the 6th to 8th aspects,

[0080] The area of the main pattern increased by the expansion correction is 5% or less of the area S1 of the auxiliary pattern lost due to the black defect.

[0081] (13th aspect)

[0082] The correction method of the photomask of the 13th aspect of the present application is based on any one of the 6th to 8th aspects,

[0083] The expansion correction is performed by retreating at least one of the four sides of the square main pattern toward the light-shielding portion side.

[0084] (14th aspect)

[0085] The correction method of the photomask of the 14th aspect of the present application is based on any one of the 6th to 8th aspects,

[0086] The expansion correction is performed by removing the edge of the light-shielding film by laser ablation or ion beam etching.

[0087] (15th aspect)

[0088] The correction method of the photomask of the 15th aspect of the present application is based on any one of the 1st, 2nd, 6th, 7th, and 8th aspects,

[0089] The auxiliary pattern is disposed in the vicinity of the main pattern, and the light intensity distribution of the exposure light transmitted through the main pattern formed on the transfer body is changed by the light transmitted through the auxiliary pattern, thereby increasing the depth of focus.

[0090] (16th aspect)

[0091] The correction method of the photomask of the 16th aspect of the present application is based on any one of the 1st, 2nd, 6th, 7th and 8th aspects,

[0092] The transfer pattern satisfies the following formula (1).

[0093] 0.8 ≤ W1 ≤ 4.0 … (1)

[0094] (17th aspect)

[0095] The correction method of the photomask of the 17th aspect of the present application is based on any one of the 1st, 2nd, 6th, 7th and 8th aspects,

[0096] The transfer pattern satisfies the following formula (2).

[0097]

[0098] (18th aspect)

[0099] The correction method of the photomask of the 18th aspect of the present application is based on any one of the 1st, 2nd, 6th, 7th and 8th aspects,

[0100] The transfer pattern satisfies the following formula (3) when a distance between a center of the main pattern and a center in a width direction of the auxiliary pattern is set as P (μm).

[0101] 1.0 < P ≤ 5.0 … (3)

[0102] (19th aspect)

[0103] The correction method of the photomask of the 19th aspect of the present application is based on any one of the 1st, 2nd, 6th, 7th and 8th aspects,

[0104] The shape of the auxiliary pattern is a polygonal band centered on a barycenter of the main pattern.

[0105] (20th aspect)

[0106] The correction method of the photomask of the 20th aspect of the present application is based on any one of the 1st, 2nd, 6th, 7th and 8th aspects,

[0107] The transfer pattern forms a hole pattern on a transfer body.

[0108] (21st aspect)

[0109] The correction method of the photomask of the 21st aspect of the present application is based on the 20th aspect,

[0110] The hole pattern is an isolated hole pattern.

[0111] (22nd aspect)

[0112] The 22nd aspect of the present application is a photomask formed by forming a transfer pattern on a transparent substrate,

[0113] The photomask is characterized in that

[0114] The transfer pattern includes:

[0115] a main pattern composed of a light-transmitting portion having a diameter of W1 (μm);

[0116] an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and

[0117] a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern,

[0118] The light-blocking portion is formed by forming a light-blocking film on the transparent substrate,

[0119] The auxiliary pattern is disposed in a region of a polygonal band surrounding the periphery of the main pattern through the light-blocking portion, and is composed of a phase-shifting portion formed by forming a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic of shifting light of a representative wavelength of exposure light by substantially 180 degrees, and having a transmittance T (%) for the light of the representative wavelength,

[0120] A complementary film having light-blocking properties composed of a material different from the light-blocking film is formed in the region of the polygonal band.

[0121] (23rd aspect)

[0122] The photomask of the 23rd aspect of the present application is based on the 22nd aspect,

[0123] The complementary film is formed to be 1 / 8 or less of the area of the polygonal band.

[0124] (24th aspect)

[0125] The photomask of the 24th aspect of the present application is based on the 22nd or 23rd aspect,

[0126] In the polygonal band, the complementary film is a laser CVD film.

[0127] (25th aspect)

[0128] The 25th aspect of the present application is a photomask formed by forming a transfer pattern on a transparent substrate,

[0129] The photomask is characterized in that

[0130] The transfer pattern includes:

[0131] a main pattern composed of a light-transmitting portion having a diameter of W1 (μm);

[0132] an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and

[0133] a light-shielding portion constituting a region other than the main pattern and the auxiliary pattern,

[0134] the light-shielding portion is formed by at least a light-shielding film on the transparent substrate,

[0135] the auxiliary pattern is disposed in a region of a polygonal band surrounding the main pattern through the light-shielding portion, and is composed of a phase shift portion formed by a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic of shifting a representative wavelength of exposure light by substantially 180 degrees, and having a transmittance T (%) for the representative wavelength of light,

[0136] the semi-light-transmitting film or a light-shielding complementary film composed of a material different from the semi-light-transmitting film is formed in the region of the polygonal band,

[0137] at least a part of a peripheral edge of the main pattern has a laser ablation cross section or an ion beam etching cross section in which the semi-light-transmitting film is removed by a prescribed width.

[0138] (26th Mode)

[0139] The photomask of the 26th mode of the present application is based on the 25th mode,

[0140] the main pattern is a rectangle, and at least one of the four sides thereof has the laser ablation cross section or the ion beam etching cross section.

[0141] (27th Mode)

[0142] The photomask of the 27th mode of the present application is based on the 25th mode,

[0143] the main pattern is a square, and at least two of the four sides thereof have the laser ablation cross section or the ion beam etching cross section.

[0144] (28th Mode)

[0145] The photomask of the 28th mode of the present application is based on any one of the 22nd, 23rd and 25th modes,

[0146] the auxiliary pattern is disposed in the vicinity of the main pattern, and the intensity distribution of the exposure light transmitted through the main pattern is changed by the light transmitted through the auxiliary pattern, thereby increasing the depth of focus.

[0147] (Method 29)

[0148] The photomask of embodiment 29 of the present invention is based on any of embodiments 22, 23, and 25.

[0149] The transfer pattern satisfies the following formula (1).

[0150] 0.8≤W1≤4.0…(1)

[0151] (Method 30)

[0152] The photomask of the 30th embodiment of the present invention is based on any of the embodiments 22, 23, and 25.

[0153] The transfer pattern satisfies the following equation (2).

[0154]

[0155] (Method 31)

[0156] The photomask of the 31st embodiment of the present invention is based on any of the embodiments 22, 23, and 25.

[0157] When the distance between the center of the main pattern and the center of the auxiliary pattern in the width direction is set to P (μm), the transfer pattern satisfies the following equation (3).

[0158] 1.0 <P≤5.0…(3)

[0159] (Method 32)

[0160] The photomask of the 32nd embodiment of the present invention is based on any of the 22nd, 23rd, and 25th embodiments.

[0161] The transfer pattern is a pattern used in the manufacture of display devices.

[0162] (Method 33)

[0163] The 33rd aspect of the present invention is a method for manufacturing a photomask, which includes the photomask modification method described in any of the first, second, sixth, seventh and eighth aspects above.

[0164] (Method 34)

[0165] The 34th aspect of the present invention is a method for manufacturing a display device, wherein the method uses a photomask as described in any of the 1st, 2nd, 6th, 7th and 8th aspects above to irradiate the transfer pattern with exposure light including at least one of i-line, h-line and g-line, thereby transferring the pattern onto the transfer object.

[0166] (Method 35)

[0167] The 35th aspect of the present invention is a method for manufacturing a display device, wherein the method uses a photomask as described in any of the 22nd, 23rd and 25th aspects above to irradiate the transfer pattern with exposure light including at least one of i-line, h-line and g-line, thereby transferring the pattern onto the transfer object.

[0168] Invention Effects

[0169] According to the present invention, defects arising in a fine transfer pattern having a main pattern and an auxiliary pattern can be efficiently corrected to restore the optical performance achieved by the transfer pattern. Attached Figure Description

[0170] Figure 1(a) is a top view of a photomask (reference example 1) as one embodiment of the correction method of the present invention. The photomask (photomask I) has a transfer pattern including a main pattern and an auxiliary pattern disposed near the main pattern.

[0171] Figure 1(b) is a cross-sectional view of position AA in Figure 1(a).

[0172] Figure 1(c) is a cross-sectional view at position AA of Figure 1(a) in the case of a modified photomask having an auxiliary pattern of a cutout formed on a transparent substrate without forming a semi-transparent film.

[0173] Figure 1(d) is a top view schematic diagram showing the pattern of the photomask of Reference Example 2.

[0174] Figure 1(e) is a graph showing the performance evaluation of each transfer pattern in Reference Examples 1 and 2.

[0175] Figure 2 (a) is a top view of photomask I. Figure 2 (b) is in Figure 2 The light intensity distribution curves in the dashed section of (a) at just focus and at defocus at 25μm and 50μm.

[0176] Figure 3 (a) is a top view showing the occurrence of white defects on a portion of the auxiliary pattern of the octagonal band in photomask I. Figure 3 (b) is in Figure 3 The light intensity distribution curves at positive focus and at defocus at 25μm and 50μm are shown in the dashed section of (a). Figure 3 (c) is a top view showing the occurrence of black defects on a portion of the auxiliary pattern of the octagonal band in photomask I. Figure 3(d) is Figure 3 The light intensity distribution curves at positive focus and at defocus at 25μm and 50μm are shown in the dashed section of (c).

[0177] Figure 4 This is a top view schematic diagram showing the case where the auxiliary pattern of the octagonal strip of photomask I is evenly divided into central corner sections A to H.

[0178] Figure 5 (a) is the result obtained by simulation calculation of the transfer performance (DOF, EL) of the patterns of Reference Example 1 and Reference Example 2 and Embodiment 1 of the present invention. Figure 5 (b) is a top view of the normal photomask I in Reference Example 1. Figure 5 (c) is a top view of the binary mask in Example 2. Figure 5 (d) is a top view of Embodiment 1, assuming that section 1 of the auxiliary pattern that produces the defect becomes a light-blocking part.

[0179] Figure 6 (a) is a top view showing the area where white defects are generated on the auxiliary pattern of photomask I. Figure 6 (b) is a top view showing the situation where a light-shielding supplementary film is formed to correct the white defect.

[0180] Figure 7 This is a top-view schematic diagram illustrating an example of black defects occurring in two sections (2 / 8 of the central corner section) of the auxiliary pattern of a photomask. Figure 7 (a) (both sides, Examples 2-4) is a top view showing the case where, without changing the center of gravity of the main pattern, the two opposite sides of the main pattern are moved back by the same size towards the light-shielding part relative to the outline of the original main pattern shown by the dashed line, thereby expanding the size of the main pattern. Figure 7 (b) (four sides, Examples 5-7) is a top view showing the case where, without changing the center of gravity of the main pattern, the four sides of the main pattern are moved back towards the light-shielding part by the same dimension relative to the outline of the original main pattern shown by the dashed line, thereby expanding the size of the main pattern. Figure 7 (c) (center of gravity shift, Examples 8-10) is a top view showing the case where, relative to the outline of the original main pattern shown by the dashed line, one edge of the main pattern is moved back towards the light-shielding part, thereby expanding the size of the main pattern.

[0181] Figure 8 It means to Figure 7 Figures (a) to (c) show the results of DOF and EL obtained by applying modified photomask I through simulation.

[0182] Figure 9 This is a top-view schematic diagram showing the situation where the auxiliary patterns of the four sections (4 / 8 of the central corner section) in photomask I are damaged and become black defects.

[0183] Figure 10 It means targeting Figure 9 The photomask I shown is obtained by means of... Figure 7 (a)~(c) (Examples 2~10) The area of ​​the main pattern is expanded using the same method, and the results of DOF and EL are obtained through simulation.

[0184] Figure 11 This is a top-view schematic diagram showing the situation where the auxiliary patterns of the five sections (5 / 8 of the central corner section) in photomask I are damaged and become black defects.

[0185] Figure 12 It means targeting Figure 11 The light mask I shown is used in conjunction with... Figure 7 (a)~(c) (Examples 2~10) The area of ​​the main pattern is expanded using the same method, and the results of DOF and EL are obtained through simulation.

[0186] Figure 13 This is a top-view diagram illustrating a variation of the combination of auxiliary and main patterns.

[0187] Figure 14 This is a cross-sectional schematic diagram illustrating an example of a method for manufacturing photomask I.

[0188] Explanation of the label

[0189] 1…Main Pattern

[0190] 2…Auxiliary patterns

[0191] 3…Light shielding part

[0192] 4…Light-transmitting section

[0193] 5… Phase shift section (semi-transparent section)

[0194] 10…Transparent substrate

[0195] 11… Semi-transparent film

[0196] 12…Light-shielding film

[0197] 12p…light-blocking film pattern

[0198] 13…First photoresist film

[0199] 13p… First resist pattern

[0200] 14…Second photoresist film

[0201] 14p…Second resist pattern

[0202] 16…Replenishing membrane

[0203] 20… Excavation Department

[0204] 30…photomask blank

[0205] FW…White Defect

[0206] FB…Black Flaw Detailed Implementation

[0207] The embodiments of the present invention will now be described. In this embodiment, a method for correcting defects generated on a photomask will be described as follows. The photomask has a main pattern with a diameter of W1 (μm) formed by a light-transmitting portion and an auxiliary pattern with a width of d (μm) disposed near the main pattern and not imaged by an exposure device.

[0208] [Regarding the photomask for defect correction objects]

[0209] Figures 1(a) and 1(b) illustrate a photomask (hereinafter, photomask I) as one embodiment of the modification method to which the present invention is applied. Furthermore, only components appearing for the first time are labeled, and subsequent references are omitted.

[0210] The photomask I has a transfer pattern on the transparent substrate 10, which is formed by patterning the light-shielding film 12 and the semi-transparent film 11 respectively, and has a light-transmitting part 4, a light-shielding part 3, and a phase-shifting part 5.

[0211] Furthermore, the term "transfer pattern" as used in this application refers to a pattern designed for a device to be obtained using a photomask, a pattern that is the object of the modifications described later, or a modified transfer pattern that has been modified, and these terms are used according to their context.

[0212] The photomask I shown in Figure 1(a) includes a main pattern 1 and an auxiliary pattern 2 disposed near the main pattern. The auxiliary pattern is not imaged by the exposure apparatus that exposes the photomask I and has a width d (μm).

[0213] In photomask I, the main pattern and the auxiliary pattern are preferably configured such that the phase difference between their transmitted light and that of each other is approximately 180 degrees. Specifically, the main pattern is composed of a light-transmitting portion that exposes the transparent substrate, and the auxiliary pattern can be a phase-shifting portion that shifts the phase of the transmitted light by approximately 180 degrees. For example, as shown in FIG1(b), the auxiliary pattern can be configured as a pattern formed on the transparent substrate by forming a semi-transparent film (so-called a phase-shifting film) that shifts the phase of the transmitted light by approximately 180 degrees.

[0214] Alternatively, as shown in the variation of Figure 1(c), the auxiliary pattern can be formed by creating a cutout 20 of a predetermined size on the surface of the transparent substrate, and the main pattern and the auxiliary pattern have the aforementioned phase difference. The structure of the auxiliary pattern will now be described primarily using the structure shown in Figure 1(b), where a semi-transparent film (phase-shifting film) that shifts the phase of transmitted light by approximately 180 degrees is formed on the transparent substrate. Hereinafter, such a phase-shifting portion will also be referred to as a semi-transparent portion.

[0215] The area other than the main pattern and auxiliary pattern becomes a light-shielding part on the transparent substrate, where at least a light-shielding film is formed.

[0216] In Figure 1(b), in the light-shielding section, a semi-transparent film and a light-shielding film are stacked on a transparent substrate. However, the light-shielding film can be a single layer, or the stacking order can be the reverse of that of the semi-transparent film.

[0217] The main pattern of photomask I can form a hole pattern on the substrate (such as the panel of a display device), with significant effects when the diameter (W1) of the main pattern is less than 4 μm. According to existing binary masks, it is difficult to transfer the fine hole pattern of such size required to achieve a high-definition display device, while photomask I controls the interference of light and achieves excellent transfer conditions through its design.

[0218] Here, an auxiliary pattern composed of phase-shifting sections is positioned near the light-transmitting section and interposed as a light-shielding section between it and the light-transmitting section. Furthermore, the light transmitted through the auxiliary pattern alters the light intensity distribution formed on the substrate by the exposure light transmitted through the light-transmitting section. For example, this has the following effects: increasing the peak value of the light intensity distribution curve, increasing the depth of focus (DOF) of the transferred image, and / or increasing the exposure latitude (EL).

[0219] In many known phase-shifting masks, the inverse-phase transmitted light is interfered with at the boundary between the phase-shifting section and the light-transmitting section to achieve effects such as improved contrast. In contrast, in photomask I, a light-blocking section is inserted between the phase-shifting section and the light-transmitting section to separate them, and the aforementioned advantages are achieved by utilizing the interference of the outer edge (amplitude reversal) of the light intensity distribution of the transmitted light from both sides.

[0220] By exposing photomask I, a fine main pattern (hole pattern) with a diameter of W2 (μm) (but W1≥W2) is formed on the transfer substrate in accordance with the main pattern described above.

[0221] Specifically, it is more advantageous to obtain the effects of the present invention when the diameter W1 (μm) satisfies the relationship of the following formula (1).

[0222] 0.8≤W1≤4.0…(1)

[0223] Regarding this, when the diameter W1 is less than 0.8 μm, it is difficult to achieve image resolution on the transfer substrate. When the diameter W1 exceeds 4.0 μm, it is relatively easy to obtain image resolution through existing photomasks, and the effect of photomask I is not significant.

[0224] At this point, the diameter W2 (μm) of the main pattern (hole pattern) formed on the transferred material can be set as...

[0225] 0.6≤W2≤3.0.

[0226] Furthermore, the effects of the present invention are more significantly achieved when the diameter W1 of the main pattern is 3.0 (μm) or less. Preferably, the diameter W1 (μm) of the main pattern can be set to...

[0227] 1.0≤W1≤3.0.

[0228] Alternatively, the relationship between diameters W1 and W2 can be set as W1 = W2, but preferably, W1 > W2. That is, assuming β (μm) is a bias value, when β = W1 - W2 > 0 (μm), it can be set to 0.2 ≤ β ≤ 1.0, and more preferably 0.2 ≤ β ≤ 0.8. When the photomask I is designed in this way, advantageous effects such as reducing the loss of residual film thickness of the resist pattern on the substrate can be obtained.

[0229] In the above, the diameter W1 of the main pattern represents the diameter of a circle or an approximate value thereof. For example, when the shape of the main pattern is a regular polygon, the diameter W1 of the main pattern is the diameter of the inscribed circle of the regular polygon. As shown in Figure 1(a), when the shape of the main pattern is a square, the diameter W1 of the main pattern is the length of one side of the square. The same applies to the case of the diameter W2 of the main pattern (hole pattern) being transferred, where the diameter W2 is the diameter of a circle or an approximate value thereof.

[0230] Of course, when forming finer patterns, the diameter W1 can be configured to be 2.5 (μm) or less or 2.0 (μm) or less, and the diameter W1 can also be set to 1.5 (μm) or less for the present invention to be applicable.

[0231] For the representative wavelength of the exposure light used in the exposure of the photomask I with such a transfer pattern, the phase difference φ1 between the transmitted light of the main pattern and the auxiliary pattern is approximately 180 degrees. Therefore, the semi-transparent film used in the auxiliary pattern has a phase shift characteristic that shifts the transmitted light by φ1 degrees, where φ1 is approximately 180 degrees.

[0232] Furthermore, the approximate 180 degrees here refers to a range of 180 degrees ± 15 degrees. The phase shift characteristics of the semi-transparent film are preferably within a range of 180 ± 10 degrees, and more preferably within a range of 180 ± 5 degrees.

[0233] The effect is significant when using exposure light including i-lines, h-lines, or g-lines for the exposure of photomask I. In particular, it is preferable to use a wide-band light including i-lines, h-lines, and g-lines as the exposure light. In this case, the representative wavelength can be any wavelength contained in the wide band, such as any one of i-lines, h-lines, and g-lines. For example, the g-line can be used as the representative wavelength to construct the photomask of this method.

[0234] The transmittance T of the phase-shifting portion constituting the auxiliary pattern can be as follows.

[0235] 2≤T≤100

[0236] As shown in the modified example of Figure 1(c), when the auxiliary pattern is formed by excavating a transparent substrate, the light transmittance T is 100%. On the other hand, as shown in Figure 1(b), when the auxiliary pattern is formed by forming a semi-transparent film on a transparent substrate, the transmittance T (%) of the semi-transparent film can be as follows.

[0237] 2≤T≤95

[0238] The light transmittance of such a phase-shifting section can control the optical image of the transfer pattern described later.

[0239] Preferably, 20≤T≤80.

[0240] More preferably, 30≤T≤70

[0241] A further preferred value is 35≤T≤65.

[0242] Furthermore, the transmittance T (%) is the transmittance of the semi-transparent film at the aforementioned representative wavelength, with the transmittance of the transparent substrate as a reference. This transmittance is within a favorable range for coordinating with the setting of the dimension d (width of the auxiliary pattern) described later, controlling the amount of light transmitted through the reversed phase of the auxiliary pattern, and helping to improve transferability (e.g., increase DOF) by interfering with the transmitted light of the main pattern.

[0243] In photomask I, the light-shielding part disposed in the area outside the area where the main pattern and auxiliary pattern are formed can be configured as follows.

[0244] The light-shielding portion substantially does not allow light for exposure (light of representative wavelengths in the wavelength range of the i-line to the g-line). The light-shielding portion can be formed by forming a light-shielding film with an optical density of OD≥2 (preferably OD≥3, more preferably OD>3) on a transparent substrate. As described above, the light-shielding film can be laminated with other films.

[0245] Furthermore, in photomask I, there is a structure in which the area other than the main pattern and auxiliary pattern is formed only by the light-shielding part.

[0246] In the above-mentioned transfer pattern, when the width of the auxiliary pattern is d (μm), when the following formula (2) holds, the transferability of the photomask I is particularly excellent.

[0247] 0.5≤√(T / 100)×d≤1.5…(2)

[0248] In addition, the distance between the center of the width of the main pattern and the center of the width direction of the auxiliary pattern is set as the distance P (μm), and the distance P preferably follows the relationship of the following formula (3).

[0249] 1.0 <P≤5.0…(3)

[0250] More preferably, the distance P is,

[0251] 1.5 <P≤4.5,

[0252] It can be further optimized,

[0253] 2.5 <P≤4.5。

[0254] By selecting such a distance P, the interference between the transmitted light of the auxiliary pattern and the transmitted light of the main pattern can be well achieved, thereby obtaining excellent effects such as DOF.

[0255] The width d (μm) of the auxiliary pattern is below the resolution limit under the exposure conditions (exposure apparatus) applicable to the photomask. Generally, the resolution limit in the exposure apparatus used for display device manufacturing is considered to be around 3.0μm to 2.5μm (i-line to g-line), specifically...

[0256] d<3.0,

[0257] Preferably,

[0258] d<2.5,

[0259] More preferably, d < 2.0.

[0260] In addition, to ensure that the transmitted light from the auxiliary pattern interacts well with the transmitted light from the main pattern, it is set as follows:

[0261] d≥0.7,

[0262] More preferably,

[0263] d≥0.8.

[0264] In addition, d is preferred. <W1。

[0265] Furthermore, under such conditions, photomask I exhibits good transferability and is suitable for use with the correction process described later.

[0266] Furthermore, more preferably, the relationship in (2) above is the following formula (2)-1, and even more preferably, the following formula (2)-2.

[0267]

[0268] That is, when the balance between transmittance T and width d fully satisfies the above conditions, the amount of light transmitted through the reversed phase of the auxiliary pattern achieves excellent results.

[0269] As described above, the main pattern of photomask I shown in Figure 1(a) is square. Although this shape is preferred, the photomask applicable to this invention is not limited to this. For example, as... Figure 13 As illustrated, the main pattern of the photomask can be a rotationally symmetric shape including octagons and circles. Furthermore, the center of rotational symmetry can be used as the reference center for the aforementioned distance P.

[0270] Furthermore, the auxiliary pattern of photomask I shown in Figure 1(a) is an octagonal strip. This shape, as an auxiliary pattern for forming the aperture pattern, not only allows for stable manufacturing but also provides good optical performance. However, the photomask to which this invention is applicable is not limited to this. For example, as... Figure 13 As illustrated in (a) to (e), the shape of the auxiliary pattern is preferably a shape with a constant width that is rotationally symmetrical about the center of the main pattern three or more times. The design of the main pattern and the design of the auxiliary pattern can... Figure 13 The different designs of (a) to (e) are combined.

[0271] For example, an example is given where the outer perimeter of the auxiliary pattern is a regular polygon (preferably a regular 2n-sided polygon, where n is an integer of 2 or more) or a circle, such as a square, regular hexagon, regular octagon, regular decagon, regular dodecagon, or regular hexagon. Furthermore, the shape of the auxiliary pattern is preferably a shape where the outer and inner perimeters are parallel, that is, a strip of regular polygonal or circular shape with an almost constant width. This strip shape is also called a polygonal strip or a circular strip. The shape of the auxiliary pattern is preferably a regular polygonal or circular strip that surrounds the main pattern with the center of gravity of the main pattern as its center, separated by a light-blocking portion. In this case, a good balance can be achieved between the amount of transmitted light from the main pattern and the amount of transmitted light from the auxiliary pattern.

[0272] In addition, other patterns may be used in addition to the main pattern and auxiliary pattern, as long as they do not impair the effect of the present invention.

[0273] Next, regarding an example of the manufacturing method of photomask I, refer to... Figure 14 The following explanation is provided. In this explanation, only the parts that appear for the first time are assigned numbers, and subsequent parts are omitted.

[0274] like Figure 14 As shown in (a), prepare photomask blank 30.

[0275] The photomask blank 30 is formed by sequentially forming a semi-transparent film 11 and a light-shielding film 12 on a transparent substrate 10 made of glass or the like, and then coating it with a first photoresist film 13.

[0276] The semi-transparent film is preferably made of a material that fully satisfies the aforementioned transmittance and phase difference and can be wet-etched. However, when the amount of lateral etching generated during wet etching is too large, defects such as deterioration of CD accuracy and damage to the upper film caused by undercutting occur. Therefore, the preferred film thickness range is... The following is an example of a semi-transparent film with a thickness of 300 mm. The range, more preferably is Here, CD refers to Critical Dimension, which in this specification means pattern width.

[0277] Furthermore, to fully satisfy these conditions, the refractive index of the semi-transparent film material, including the representative wavelength (e.g., h-line) in the exposure light, is preferably 1.5 to 2.9. More preferably, the refractive index is 1.8 to 2.4.

[0278] Furthermore, preferably, the patterned cross section (etched surface) of the semi-transparent film formed by wet etching is nearly perpendicular to the main surface of the transparent substrate.

[0279] Regarding the materials for the semi-transparent film, examples include materials containing chromium (Cr) or materials containing a migrating metal and Si (silicon). For example, materials comprising at least one of Zr (zirconium), Nb (niobium), Hf (hafnium), Ta (tantalum), Mo (molybdenum), and Ti (titanium) and Si can be used, or materials composed of oxides, nitrides, oxynitrides, carbides, or carbonitrides containing these materials can be employed. Specifically, examples include molybdenum nitride silicide (MoSiN), molybdenum oxynitride silicide (MoSiON), molybdenum oxide silicide (MoSiO), silicon oxynitride (SiON), and titanium oxynitride (TiON).

[0280] As a method for forming a semi-transparent film, known methods such as sputtering can be applied.

[0281] A light-shielding film is formed on a semi-transparent film of a photomask preform. The method for forming the light-shielding film is the same as that for the semi-transparent film, and known methods such as sputtering can be used.

[0282] The material of the light-shielding film can be Cr or its compounds (oxides, nitrides, carbides, oxynitrides, or carbonitrides), or it can be a silicide of a metal including Mo, W, Ta, or Ti, or a compound of such a silicide. However, the material of the light-shielding film for the photomask blank is preferably a material that can be wet-etched in the same way as the semi-transparent film, and has etching selectivity for the material of the semi-transparent film. That is, preferably, the light-shielding film is resistant to the etchant of the semi-transparent film, and also resistant to the etchant of the light-shielding film.

[0283] A first photoresist film is also coated on the light-shielding film of the photomask blank. In the photomask drawing process of this method, drawing performed by a laser drawing device is preferred, and therefore a corresponding photoresist is used. The first photoresist film can be either positive or negative; it will be described below as positive.

[0284] Next, as Figure 14 As shown in (b), a drawing apparatus is used to draw the first photoresist film according to drawing data based on a transfer pattern (first drawing). Furthermore, the first photoresist pattern 13p obtained by development is used as a mask to wet-etch the light-shielding film. This delineates the area that becomes the light-shielding portion, and also delineates the area of ​​the auxiliary pattern (light-shielding film pattern 12p) surrounded by the light-shielding portion.

[0285] Next, as Figure 14 As shown in (c), the first resist pattern is peeled off.

[0286] Next, as Figure 14 As shown in (d), a second photoresist film 14 is applied to the entire surface including the formed light-shielding film pattern.

[0287] Next, as Figure 14As shown in (e), a second depiction is performed on the second photoresist film 14, and a second photoresist pattern 14p is formed by development. Then, using the second photoresist pattern and the aforementioned light-shielding film pattern as a mask, a semi-transparent film is wet-etched to form a region of the main pattern consisting of the light-transmitting portion that exposes the transparent substrate. Preferably, the second photoresist pattern covers the region that becomes the auxiliary pattern, and an opening is provided in the region of the main pattern consisting of the light-transmitting portion. The depiction data of the second depiction is applied in such a way that the edge of the light-shielding film is exposed through the opening. This absorbs the alignment deviations that occur between the first and second depictions, preventing deterioration of the CD accuracy of the transfer pattern, and thus enabling precise alignment of the center of gravity of the main pattern and the auxiliary pattern.

[0288] Next, as Figure 14 As shown in (f), the second resist pattern is peeled off to complete the photomask I of this method shown in Figures 1(a) and (b).

[0289] Wet etching can be used when manufacturing such photomasks. Wet etching has the properties of isotropic etching, so when considering the thickness of the semi-transparent film, it is useful from the point of view of ease of processing for the width d of the auxiliary pattern to be 1 μm or more, preferably 1.2 μm or more.

[0290] Regarding the photomask I of this method shown in Figures 1(a) and 1(b), its transfer performance was compared and evaluated through optical simulation.

[0291] Here, Reference Example 1 and Reference Example 2 are prepared on the transfer body as transfer patterns for forming hole patterns, and optical simulations are performed to show what kind of transfer performance is represented when common exposure conditions are set.

[0292] (Refer to Example 1)

[0293] The photomask of Reference Example 1 is a photomask having the same structure as the photomask I described in Figures 1(a) and 1(b). Here, the main pattern formed by the light-transmitting part is a square with a side (diameter) (i.e., W1) of 2.0 (μm), and the auxiliary pattern formed by the semi-transparent part is an octagonal strip with a width d of 1.3 (μm). The distance P between the center of the width of the main pattern and the center of the width direction of the auxiliary pattern is 3.25 (μm).

[0294] The auxiliary pattern is formed by forming a semi-transparent film on a transparent substrate. The transmittance T of this semi-transparent film to the g-wavelength is 45%, and the phase shift is 180 degrees. In addition, the light-shielding portion surrounding the main pattern and the auxiliary pattern is essentially composed of a light-shielding film (preferably OD>3) that does not transmit light for exposure.

[0295] (See Example 2 for reference)

[0296] As shown in Figure 1(d), the photomask of Reference Example 2 has a so-called binary mask pattern composed of a light-shielding film pattern formed on a transparent substrate. In this photomask, a main square pattern 1 composed of light-transmitting portions exposed on the transparent substrate is surrounded by light-shielding portions (preferably OD>3) 3. The diameter W1 (one side of the square) of the main pattern is 2.0 (μm).

[0297] In both examples 1 and 2, the photomasks form a hole pattern with a diameter W2 of 1.5 μm on the substrate to be transferred. The applicable exposure conditions in the simulation are as follows: the exposure light is a wide wavelength range including the i-line, h-line, and g-line, and the light intensity ratio is g:h:i = 1:1:1.

[0298] In the optical system of the exposure apparatus, the aperture ratio NA is 0.1 and the coherence factor σ is 0.5. The thickness of the positive photoresist film formed on the substrate to control the cross-sectional shape of the resist pattern is 1.5 μm.

[0299] Under the above conditions, the performance evaluation of each transfer pattern is shown in Figure 1(e).

[0300] [Optical Evaluation of Photomasks]

[0301] For example, in order to transfer a small-diameter, finely translucent pattern onto a substrate, the intensity distribution of the transmitted light, achieved by the exposure light passing through the photomask and the spatial image formed on the substrate, must be well-defined. Specifically, it is important that the peaks of the transmitted light intensity distribution have a sharp inclination, achieving a near-vertical rise, and that the absolute value of the peak light intensity is high (relatively high enough relative to the intensity of any surrounding subpeaks).

[0302] To further quantify, when evaluating photomasks in terms of optical performance, the following metrics can be used.

[0303] (1) Depth of Focus (DOF)

[0304] The depth of focus (DOF) is the size used to keep the variation relative to the target CD within a specified range (here, ±15%). If the DOF value is high, it is less affected by the flatness of the substrate (e.g., the panel substrate for a display device), and fine patterns can be reliably formed, suppressing CD deviation.

[0305] (2) Exposure Latitude (EL)

[0306] The tolerance of the light intensity used for exposure, which is used to keep the variation relative to the target CD within a specified range (in this case, ±15%).

[0307] Based on the above, the performance of each sample of the simulation object is evaluated as shown in Figure 1(e). The focal depth (DOF) of the photomask in Reference Example 1 is much better than that in Reference Example 2. The photomask is not easily affected by the flatness of the object being transferred, and exhibits stable pattern transfer.

[0308] In addition, the photomask of Reference Example 1 also exhibits an excellent value of over 10.0% in EL, that is, stable transfer conditions can be achieved relative to changes in the amount of light used for exposure.

[0309] Furthermore, the Dose value (the amount of irradiated light used to form a pattern of the target size) of the photomask in Reference Example 1 is considerably smaller than that in Reference Example 2. This demonstrates the advantage that, even when manufacturing large-area display devices, the exposure time does not increase or can be shortened, in the case of the photomask in Reference Example 1.

[0310] [Regarding the defects generated in photomask I]

[0311] Figure 2 This indicates that the photomask I mentioned above (refer to Example 1) is exposed. Figure 2 When (a) is formed, the light intensity distribution curve of the optical image formed on the transferred material is ( Figure 2 (b)). In particular, Figure 2 (b) is in Figure 2 The light intensity distribution curves at positive focus and at defocus at 25 μm and 50 μm are shown in the dashed section of (a). Furthermore, in Figure 2 In (b), the μm values ​​for these defocusing amounts are omitted; + indicates the direction closer to the focal point, and - indicates the direction farther from the focal point. The central peak corresponding to the main pattern is very high and steep. In addition, the intensity difference between the secondary peaks generated on both sides and the main peak is large enough that it does not affect the transfer of the main pattern. Furthermore, the defocusing has little effect on CD variation.

[0312] in addition, Figure 3 The light intensity distribution curve of the optical image is shown when a defect is generated on the auxiliary pattern of the octagonal band of the photomask I. Figure 3 (a) indicates a case where a white defect FW is generated in a portion of the auxiliary pattern of the octagonal strip of photomask I. Here, as... Figure 4 As shown, regarding one of the sections (hereinafter also referred to as the central angle sections) in which the auxiliary pattern is divided by the central angle (here, one section in the section in which the auxiliary pattern of the octagonal band is divided into 8 equal parts, i.e., the whole 1 / 8 section, see reference). Figure 4 The transferability of the ink was studied to investigate the occurrence of white defects. Figure 3As shown in (b), besides the light intensity ratio of the main peak of the light intensity distribution... Figure 2 Besides the weakness in (b), the difference in light intensity between the main peak and the sub-peak is relatively small. In particular, when defocused, the influence of the sub-peak on the resist on the substrate (damage to the resist pattern) cannot be avoided. Therefore, the influence of white defects generated in the auxiliary pattern is not easily ignored. This phenomenon also occurs when the auxiliary pattern is a polygonal body or a circular band other than an octagonal band.

[0313] Figure 3 (c) indicates the case where a black defect FB is generated in a portion of the auxiliary pattern of the octagonal strip of photomask I (also a 1 / 8 partition as described above). Figure 3 (d) represents the light intensity distribution curve of the optical image at this time. For example, during the manufacturing process, such black defects are prone to occur when there is residual light-blocking film on the semi-transparent film. However, if it is a black defect, the light intensity of the main peak in the light intensity distribution of the optical image will decrease slightly, but it is estimated that there will not be a significant problem with the transferability. That is, whether the defect generated on the auxiliary pattern is a black defect or a white defect, it will damage the optical performance by reducing the peak of the light intensity distribution formed on the transferred material, and compared with black defects, white defects have a greater impact on the transferability of the main pattern. In other words, Figure 3 The peak value of the light intensity distribution in the case of black defects shown in (d) is higher than that of the peak value ... Figure 3 In the case of white defects shown in (b), the peak value of the light intensity distribution is high, and the slope of the mountain is also steep. Regarding this point, it is believed that the same applies not only to auxiliary patterns with octagonal bands, but also to auxiliary patterns that surround the main pattern with a light-blocking part.

[0314] Based on the above knowledge, the inventors have studied a method for correcting defects generated on photomask I. Specifically, they have studied a method for at least partially restoring the optical properties of a transfer pattern that have deteriorated due to defects.

[0315] In general, defects that increase the amount of transmitted light in a photomask pattern due to the shedding of the required film are called white defects, while defects that decrease the amount of transmitted light due to attached residue are called black defects. In this application, in addition to these cases, when a phase-shifting portion is formed by cutting into a transparent substrate, insufficient cutting to achieve a sufficient phase-shifting effect is also considered a white defect. This is because the phase-shifting effect of the auxiliary pattern decreases, producing an effect similar to that of the aforementioned white defects.

[0316] [Defect Correction Method 1]

[0317] Below, the photomask I (which generates black defects in one partition of the auxiliary pattern of the octagonal strip) is calculated through simulation.Figure 5 The transfer performance (DOF, EL) of (d) was calculated and compared with that of the normal photomask I in Reference Example 1. Figure 5 (b) and the binary mask of Reference Example 2 ( Figure 5 A comparison was made between (c) and (c). The comparison results are in Figure 5 (a) shows.

[0318] As mentioned in Figure 1, the binary mask can form a hole pattern of the target size (1.5 μm) on the substrate with a Dose value (the amount of light during exposure) approximately 1.5 times that of photomask I. However, with the Dose value most suitable for normal photomask I (here, 82.0 mJ / cm²), an image of the target size could not be formed. Therefore, in order to form an image of the target size, the diameter of the main pattern was increased to 2.28 μm. Figure 5 In Reference Example 2 (a), it is marked "Note 1," which indicates that the diameter of the main pattern was changed as described above. Additionally, in the case of… Figure 3 In the white defect transfer pattern shown in (a), under the above exposure conditions, a transfer image of the target size cannot be obtained on the transfer object, and the values ​​of DOF and EL cannot be calculated.

[0319] like Figure 5 As shown in (a), the DOF and EL of Embodiment 1, which has black defects, are smaller than those of Reference Example 1, which is a normal pattern. On the other hand, the DOF and EL of Embodiment 1 exceed those of the binary mask of Reference Example 2 (which does not have an auxiliary pattern and obtains the target size only by enlarging the main pattern), indicating that the residual auxiliary pattern can improve the transferability. Therefore, as a defect correction method, the criterion is that at least any one of DOF and EL exceeds the corresponding one of the binary mask of Reference Example 2.

[0320] Furthermore, according to the inventors' research, thanks to recent improvements in the performance of exposure equipment, transfer printing can be performed with an EL of 4% or higher. On the other hand, regarding DOF, it is preferable to exceed 20 μm due to factors such as the flatness of the large substrate used in display device manufacturing. Regarding these two parameters, the larger one is preferred; in practical cases where a compromise is necessary, DOF is often given priority. Therefore, in order to obtain a DOF exceeding 20 μm and a EL that is as large as possible, defect correction methods have been investigated.

[0321] Figure 6(a) indicates the location where a white defect occurs in the auxiliary pattern of photomask I. This defect occurs in one of the eight zones A to H of the auxiliary pattern. The defect occurs in less than 1 / 8 of the central corner zone, and the area lost as part of the auxiliary pattern is also less than 1 / 8 of the entire auxiliary pattern. Therefore, this white defect is corrected by forming a supplementary film 16 with light-blocking properties (e.g., OD > 3) (supplementary film correction). Figure 6 (b)). The supplementary film covers the white defect area and is within the area of ​​the aforementioned one partition. Furthermore, the supplementary film can be a CVD film formed by laser CVD. Therefore, the composition of the supplementary film differs from that of the aforementioned light-shielding film. On the other hand, by making such a modification, transferability no less than that of Example 1 can be obtained.

[0322] That is, regarding the decreased optical performance of the transfer pattern due to white defects generated on the auxiliary pattern, by forming a light-shielding supplementary film on the white defect area, the same light-shielding performance as the light-shielding area can be achieved, thereby at least partially restoring the optical function. Here, optical performance includes the peak height of the light intensity distribution curve, the size of DOF, and the size of EL. In addition, it includes the case where a transfer image of a specified size (within ±15% of the target CD) changes from a state where it was never formed on the transfer substrate to a state where it is formed on the transfer substrate.

[0323] Furthermore, regarding the aforementioned defect correction method 1, the photomask I shown in FIG1(b) has been described, but the same correction can also be performed on the photomask shown in the modified example of FIG1(c). In this case, white defects caused by insufficient excavation of the auxiliary pattern that should have an excavated portion on the transparent substrate can be corrected by performing the aforementioned supplementary film formation.

[0324] [Defect Correction Method 2]

[0325] Figure 7 This illustrates an example of a black defect occurring in two sections (2 / 8 of the central corner section) of the auxiliary pattern of a photomask. This black defect could be caused by the formation of a supplementary film to compensate for a white defect.

[0326] However, unlike defect correction method 1, the loss area of ​​the auxiliary pattern also reaches 2 / 8 of the central corner partition, and its impact is greater. Therefore, in this state, it may not be possible to meet the DOF of 20 μm. The reason is believed to be that in normal photomask I, a portion of the transmitted light appearing in the light intensity distribution formed by the auxiliary pattern helps increase the light intensity achieved by the transmitted light from the main pattern. In contrast, when the defect of the auxiliary pattern exceeds 1 / 8 of its area, it cannot sufficiently help increase the aforementioned light intensity. In fact, according to the inventors' research, as... Figure 7As shown, when black defects occur in two zones, under the same exposure conditions as described above, it is impossible to form a transfer image of the target size, and therefore it is impossible to calculate DOF and EL.

[0327] Therefore, in Examples 2-4, the photomask I, which has black defects in 2 / 8 of the central corner area, was modified by expanding the size of the main pattern (expansion correction) to compensate for the lost effect of the auxiliary pattern increasing the light intensity of the main pattern. That is, instead of modifying the auxiliary pattern that has defects, expansion correction was performed on the main pattern. As a result, it is not necessary to form a correction film with a specified transmittance and phase difference in the black defect area. The size of the main pattern can be expanded by moving at least one of the four sides of the quadrilateral (in this case, a square) main pattern backward toward the light-shielding part.

[0328] In embodiments 2-4, without changing the center of gravity of the main pattern, relative to the outline (square) of the normal main pattern shown by the dotted lines, the two opposite sides of the main pattern are moved back towards the light-shielding part by the same size, thereby expanding the size of the main pattern. Figure 7 of (a), Figure 8 (Both sides). In embodiments 5-7, without changing the center of gravity of the main pattern, relative to the outline of the normal main pattern shown by the dotted lines, the four sides of the main pattern are moved back towards the light-shielding part by the same size, thereby expanding the size of the main pattern ( Figure 7 (b) Figure 8 (The "four sides"). Furthermore, in embodiments 8-10, relative to the outline of the normal main pattern shown by the dashed lines, one side of the main pattern is moved back towards the light-shielding portion, thereby expanding the size of the main pattern. Figure 7 (c) Figure 8 (The "center of gravity shift"). In Examples 8-10, the center of gravity of the main pattern shifts towards the expansion edge.

[0329] Furthermore, the method of expanding the size of the main pattern can also be an expansion method other than the illustrated method. For example, the two adjacent sides of the square main pattern can be moved back towards the light-blocking part.

[0330] The size expansion of the main pattern can be achieved by removing a specified amount of the edge portion of the light-shielding film located on one side of the main pattern through laser ablation using a laser CVD device or ion beam etching using a FIB device.

[0331] For this modified photomask I, the DOF and EL were calculated through simulation. The calculation results are... Figure 8As shown in the figure. In addition, by generating the location of the missing partitions on the auxiliary pattern, the change in the spatial image shape of the light intensity can be estimated. Here, the DOF and EL values ​​in the X and Y directions are calculated, and the smaller values ​​are shown in the figure for evaluation.

[0332] according to Figure 8 Under any expansion method, by applying expansion correction under the aforementioned exposure conditions, a transfer image (aperture pattern) can be obtained on the substrate, along with the DOF and EL at that time. That is, through expansion correction, the recovery of optical properties lost due to defects can be observed. Furthermore, when the area of ​​the main pattern is expanded at a constant ratio relative to the area lost by the auxiliary pattern, a desired tendency for DOF recovery can be observed. In the calculations, the area of ​​one partition of the auxiliary pattern in photomask I is 3.5 μm. 2 .

[0333] Figure 9 This indicates a 4 / 8 loss in the central corner section of the auxiliary pattern of the photomask. To address this defect, an expansion correction was performed by expanding the area of ​​the main pattern, using the same method as in Examples 2-10. Figure 10 Examples 11 to 19 are shown.

[0334] Figure 11 This indicates a 5 / 8 loss in the central corner section of the auxiliary pattern of the photomask. To address this defect, simulation results show that an expansion correction was implemented by expanding the area of ​​the main pattern using the same method as in Examples 2-10. Figure 12 Examples 20 to 28 are shown.

[0335] As can be clearly seen from the above description, when a black defect occurs in more than 2 / 8 of the central corner section of the auxiliary pattern, if the hole pattern of the target size is not formed on the transfer body, the lost optical performance can be at least partially recovered when the expansion correction is performed as described above. That is, when the loss area of ​​the auxiliary pattern exceeds 1 / 8, the expansion correction of the main pattern can effectively restore the optical performance.

[0336] Furthermore, the above explanation addresses the case where black defects occur in multiple consecutive central corner sections, resulting in partial loss of the auxiliary pattern. On the other hand, it is assumed that black defects occur in discontinuous locations within the multiple central corner sections. Therefore, optical simulations were performed to examine the changes in the light intensity distribution formed on the transfer substrate and the effect of expanding the main pattern in response to these various discontinuous defect locations. As a result, due to the discontinuous defects, the auxiliary pattern, which increases the light intensity distribution formed by the transmitted light of the main pattern, tends to partially lose its functional properties, similar to the continuous case described above. Moreover, through the expansion correction of the main pattern, the reduced functionality can also be observed to be restored.

[0337] The expansion direction during the expansion correction of the main pattern can be any of four directions, two directions, or one direction. However, it is preferable that the expansion correction of the main pattern is performed within a range where any part of the outer edge of the main pattern does not come into contact with the residual auxiliary pattern.

[0338] Furthermore, according to the inventors' research, due to the occurrence of black defects, the peak value of the light intensity distribution on the transferred material decreases, and this decrease is substantially proportional to the area of ​​the auxiliary pattern lost due to the black defects. Here, by performing an expansion correction on the main pattern, the peak position of the decreased light intensity is oriented towards the recovery direction. However, it is preferable to perform the expansion correction within a range that does not exceed the peak height (reference) of the light intensity obtained under defect-free conditions. This avoids a significant decrease in EL.

[0339] In addition, from Figure 8 , Figure 10 , Figure 12 The results show that the ratio (S2 / S1) of the expanded area (increased area) S2 of the main pattern to the lost area S1 of the auxiliary pattern is greater than zero, preferably less than 5%. In particular, when the ratio (S2 / S1) is between 2.5% and 5%, the recovery effects of both DOF and EL can be observed. Hereinafter, the ratio (S2 / S1) is labeled as a percentage (100×S2 / S1).

[0340] Focusing on DOF (Depth of Field), when evaluating various sets of examples with auxiliary pattern defects in 2 to 5 zones, a ratio S2 / S1 of 4.3 to 4.6% is advantageous. Focusing on EL (Effective Field), when evaluating various sets of examples with defects, a ratio S2 / S1 of 2.5 to 4.1% is advantageous. Furthermore, emphasizing the balance between DOF and EL, when evaluating various sets of examples with defects, a ratio S2 / S1 of 3.4 to 4.1% is advantageous.

[0341] Therefore, when the ratio S2 / S1 is 3.4 to 4.6%, it can be said that the preferred transferability with respect to DOF is achieved.

[0342] Furthermore, it is known that the correction method of the present invention can work more effectively when the defect of the auxiliary pattern is less than 4 / 8 of the central corner section.

[0343] Here, DOF and EL are restored by expanding the area of ​​the main pattern. However, no significant correlation is observed between the expansion method of the main pattern and the restoration of DOF and EL. That is, it can be considered that the improvement of transmitted light in the area of ​​the auxiliary pattern (the light interference between the auxiliary pattern and the transmitted light of the main pattern) is impaired according to the defect area, and the restoration of transfer performance is achieved by expanding the area of ​​the main pattern. There is a correlation between the areas of the two. In particular, when the diameter W1 (μm) is below the resolution limit of the exposure device (e.g., W1≤3), the transfer performance is controlled by the light transmittance area compared to the shape of the main pattern.

[0344] Therefore, the shape of the expanded and corrected main pattern can be either square or rectangular. However, depending on the expansion size, the main pattern and the auxiliary pattern come into contact, and it is sometimes difficult to maintain a light-shielding portion of appropriate size between them. Therefore, a square is preferred. In cases where it is difficult for the main pattern and the auxiliary pattern to come into contact (for example, in the case of a defect in the auxiliary pattern in the expansion direction), the shape of the expanded and corrected main pattern can also be rectangular.

[0345] Furthermore, while the above-described defect correction method 2 has been explained with respect to photomask I shown in Figure 1(b), it is also applicable to the photomask in Figure 1(c). In this case, when a black defect occurs due to the presence of a light-shielding film or impurities on the auxiliary pattern where the transparent substrate should have a cutout portion, or when a black defect occurs due to the formation of a light-shielding supplementary film to compensate for white defects caused by insufficient cutout, the above-described expansion correction can be applied to the main pattern to restore the transfer performance.

[0346] The present invention includes a photomask having the following features.

[0347] A photomask formed by forming a transfer pattern on a transparent substrate, the transfer pattern comprising a main pattern of diameter W1 consisting of light-transmitting portions and an auxiliary pattern disposed near the main pattern, not imaged by an exposure apparatus, and having a width d (μm). The effects of this invention can be significantly obtained when the main pattern is a hole pattern, particularly an isolated hole pattern.

[0348] The transfer pattern also includes a light-shielding portion that constitutes the area other than the main pattern and the auxiliary pattern, the light-shielding portion being formed by forming at least a light-shielding film on the transparent substrate.

[0349] The auxiliary pattern is disposed in the area of ​​the polygonal band surrounding the main pattern through the light-shielding portion, and is composed of a phase-shifting portion formed by forming a semi-transparent film on the transparent substrate. The semi-transparent film has a phase characteristic that shifts the phase of the representative wavelength of the exposure light by approximately 180 degrees, and has a transmittance T (%) for the representative wavelength of the light. The light-shielding film or a supplementary light-shielding film is formed in an area of ​​less than 1 / 8 of the area of ​​the polygonal band.

[0350] Alternatively, the auxiliary pattern is disposed in the area of ​​a polygonal band surrounding the main pattern through the light-shielding portion, and a phase-shifting portion is formed by excavating the surface of the transparent substrate to a predetermined depth, thereby creating a phase difference of approximately 180 degrees between the transmitted light of the auxiliary pattern and the transmitted light of the main pattern, and the light-shielding film or a supplementary light-shielding film is formed in an area of ​​less than 1 / 8 of the area of ​​the polygonal band.

[0351] The photomask includes a photomask that implements the modification of the present invention on the aforementioned photomask I, and its structure is as follows when viewed from above: Figure 5 The photomask or (d) shown in Embodiment 1 Figure 6 This is illustrated in the photomask shown in (b).

[0352] In addition, the present invention includes photomasks with the following structures.

[0353] A photomask formed by forming a transfer pattern on a transparent substrate, the transfer pattern having a main pattern of diameter W1 consisting of a light-transmitting portion and an auxiliary pattern disposed near the main pattern, not imaged by an exposure device, and having a width d (μm).

[0354] The transfer pattern also includes a light-shielding portion located in the area other than the main pattern and the auxiliary pattern, which surrounds the main pattern and the auxiliary pattern. The light-shielding portion is formed by forming a light-shielding film on the transparent substrate.

[0355] The auxiliary pattern is disposed in the area of ​​a polygonal band surrounding the main pattern through the light-shielding portion, and is composed of a phase-shifting portion formed by forming a semi-transparent film on the transparent substrate. The semi-transparent film has a phase characteristic that shifts the phase of the representative wavelength of the exposure light by approximately 180 degrees, and has a transmittance T (%) for the representative wavelength of the light. The light-shielding film or a supplementary light-shielding film is formed in the area of ​​the polygonal band, and at least a portion of the periphery of the main pattern has a laser ablation section or an ion beam etching section formed by removing a predetermined width of the light-shielding film.

[0356] Alternatively, the auxiliary pattern is disposed in a polygonal band surrounding the main pattern through the light-shielding portion, and a phase-shifting portion is provided by excavating the surface of the transparent substrate to a predetermined depth, so that the transmitted light of the auxiliary pattern has a phase difference of approximately 180 degrees with the transmitted light of the main pattern. The light-shielding film or a supplementary light-shielding film is formed in the region of the polygonal band, and at least a portion of the periphery of the main pattern has a laser ablation section or an ion beam etching section formed by removing a predetermined width of the light-shielding film.

[0357] Laser ablation cross-section refers to the cross-section formed at its edge when a portion of the light-shielding film or supplementary film is removed by laser ablation. Conversely, ion beam etching cross-section refers to the cross-section formed at its edge when a portion of the light-shielding film or supplementary film is removed by a focused ion beam. Such pattern edges exhibit a different cross-sectional state from the edges of the light-shielding film in a normal pattern (edges formed by wet etching), and are formed by a correction device.

[0358] The aforementioned photomask includes a photomask obtained by implementing the modification of the present invention on the aforementioned photomask I. When viewed from above, its structure is... Figure 7 The photomasks shown in (a) to (c) are exemplified.

[0359] The photomask of the present invention modifies the photomask I shown in FIG. 1(b) or the modified photomask shown in FIG. 1(c), resulting in a situation where both a transfer pattern with expansion modification and a normal transfer pattern are simultaneously present. In this case, the shapes (e.g., diameter, aspect ratio) of the main pattern of the modified transfer pattern and the main pattern of the normal transfer pattern are different, and the area of ​​the former can be larger than the area of ​​the latter.

[0360] In addition, the present invention includes a method for manufacturing a photomask, which includes the above-described modification method.

[0361] In the above-described method for manufacturing photomask I, when defects occur in the formed semi-transparent portion, the correction method of the present invention can be applied. In this case, for example, in... Figure 14 After the second resist stripping process shown in (f), a defect inspection process and a correction process are set up, and the correction method of the present invention is applied in the correction process.

[0362] The present invention includes a method for manufacturing a display device, the method comprising the steps of: exposing the photomask of the present invention described above by an exposure apparatus, and transferring the transfer pattern onto a transfer substrate.

[0363] The manufacturing method of the display device of the present invention first prepares the photomask of the present method described above. Next, the transfer pattern is exposed, and a hole pattern with a diameter W2 of 0.6 to 3.0 μm is formed on the transfer substrate.

[0364] The exposure apparatus used can be a projection exposure method with equal magnification, preferably as follows: An exposure apparatus for use in an FPD (Flat Panel Display) has the following structure: the numerical aperture (NA) of the optical system is 0.08 to 0.15 (coherence factor σ is 0.4 to 0.9), and it includes a light source for exposure light comprising at least one of an i-line, an h-line, and a g-line. However, the effects of the invention can also be obtained by applying the present invention to an exposure apparatus with a numerical aperture (NA) of 0.10 to 0.20.

[0365] Furthermore, while the light source of the exposure apparatus used can be deformed illumination (here, refers to a light source that blocks the light component that is incident perpendicularly relative to the photomask, including oblique incident light sources such as ring illumination), the excellent effects of the present invention can be obtained by non-deformed illumination.

[0366] The application of the photomask to which the present invention is applied is not particularly limited. The photomask of the present invention can be a transmissive photomask that is preferably used in the manufacture of display devices, including liquid crystal display devices, EL display devices, etc.

[0367] In addition, in this specification, a display device refers to a device including equipment for constituting a display device.

[0368] According to the photomask of the present invention, which uses an auxiliary pattern that reverses the phase of transmitted light, the mutual interference of the exposure light transmitted through the main pattern and the auxiliary pattern can be controlled, thereby greatly improving the distribution of the spatial image formed by the transmitted light.

[0369] As an application that facilitates achieving such an effect, it is advantageous to use the photomask of the present invention for forming isolated hole patterns, such as contact holes, which are commonly used in liquid crystal and EL devices. As a type of pattern, dense patterns and isolated patterns are generally distinguished and referred to separately. A dense pattern is a pattern in which multiple patterns are arranged in a constant, regular pattern, thereby causing these patterns to optically influence each other. An isolated pattern, on the other hand, does not have such a regularly arranged pattern around it. The photomask of the present invention is particularly preferred for situations where isolated patterns need to be formed on a substrate.

[0370] Without compromising the effectiveness of the present invention, additional optical films and functional films may be used on the photomask to which the present invention is applied. For example, to prevent the light transmittance of the light-shielding film from hindering inspection and photomask position detection, the structure may be configured such that the light-shielding film is formed in an area other than the transfer pattern. Furthermore, a reflection-preventing layer for reducing the reflection of drawing light and exposure light may be provided on the surface of the semi-transparent film or the light-shielding film. Additionally, a reflection-preventing layer may also be provided on the back side of the semi-transparent film.

Claims

1. A photomask having a transfer pattern formed on a transparent substrate, the photomask being characterized in that the transfer pattern includes: a main pattern composed of a light-transmitting portion, having a diameter of Wl (μm); an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern, the light-blocking portion being formed by at least forming a light-blocking film on the transparent substrate, the auxiliary pattern surrounds a periphery of the main pattern through the light-blocking portion, and is composed of a phase-shifting portion formed by forming a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic that shifts a representative wavelength of exposure light in a range of 180 ± 15 degrees, and having a transmittance T (%) for the representative wavelength of light, a transmittance of a part of the auxiliary pattern is lower than a transmittance of other regions of the auxiliary pattern, the part is a region of a black defect, instead of the region of the black defect in the auxiliary pattern being corrected, the photomask is subjected to an expansion correction that expands a width of the main pattern.

2. The photomask according to claim 1, characterized in that the transfer pattern includes a corrected transfer pattern subjected to the expansion correction and a normal transfer pattern, a cross section of a periphery of the main pattern of the corrected transfer pattern is different from a cross section of a periphery of the main pattern of the normal transfer pattern.

3. A photomask having a transfer pattern formed on a transparent substrate, the photomask being characterized in that the transfer pattern includes: a main pattern composed of a light-transmitting portion, having a diameter of Wl (μm); an auxiliary pattern disposed in the vicinity of the main pattern, not resolved by an exposure device, having a width d (μm); and a light-blocking portion constituting a region other than the main pattern and the auxiliary pattern, the light-blocking portion being formed by at least forming a light-blocking film on the transparent substrate, the auxiliary pattern surrounds a periphery of the main pattern through the light-blocking portion, and is composed of a phase-shifting portion formed by forming a semi-light-transmitting film on the transparent substrate, the semi-light-transmitting film having a phase characteristic that shifts a representative wavelength of exposure light in a range of 180 ± 15 degrees, and having a transmittance T (%) for the representative wavelength of light, a transmittance of a part of the auxiliary pattern is lower than a transmittance of other regions of the auxiliary pattern, the part is a region of a black defect, instead of the region of the black defect in the auxiliary pattern being corrected, the photomask is subjected to an expansion correction that expands a width of the main pattern. the transfer pattern includes a normal transfer pattern and a corrected transfer pattern subjected to an expansion correction that expands a width of the main pattern instead of a region of the black defect in the auxiliary pattern being corrected, an area of the main pattern of the corrected transfer pattern is larger than an area of the main pattern of the normal transfer pattern.

4. A photomask having a transfer pattern formed on a transparent substrate, the photomask being characterized in that the transfer pattern includes: a main pattern composed of a light-transmitting portion, having a diameter of Wl (μm); an auxiliary pattern configured in the vicinity of the main pattern, not resolved by the exposure device, having a width d (μm); and a light-shielding portion constituting a region other than the main pattern and the auxiliary pattern, the light-shielding portion being formed by at least a light-shielding film on the transparent substrate, the auxiliary pattern surrounding a periphery of the main pattern through the light-shielding portion and being constituted by a phase shift portion formed by a semi-transmissive film on the transparent substrate, the semi-transmissive film having a phase characteristic that shifts a representative wavelength of exposure light in a range of 180 ± 15 degrees and having a transmittance T (%) for the representative wavelength of light, a transmittance of a part of the auxiliary pattern being lower than a transmittance of other regions of the auxiliary pattern, the part of the auxiliary pattern being a region of a black defect, the transfer pattern including a normal transfer pattern and a corrected transfer pattern in which a width of the main pattern is expanded by correction of a region of the auxiliary pattern in which the black defect is replaced, an aspect ratio of the main pattern of the corrected transfer pattern being different from an aspect ratio of the main pattern of the normal transfer pattern.

5. The photomask according to any one of claims 1 to 4, wherein the light-shielding portion is formed with the semi-transmissive film and the light-shielding film in this order, or with the light-shielding film and the semi-transmissive film in this order.

6. The photomask according to any one of claims 1 to 4, wherein the auxiliary pattern is configured in a region of a polygonal band surrounding a periphery of the main pattern through the light-shielding portion.

7. The photomask according to claim 6, wherein the part of the auxiliary pattern is a region of 1 / 8 or less of an area of the polygonal band.

8. The photomask according to any one of claims 1 to 4, wherein an optical density of the part of the auxiliary pattern is greater than 3.

9. The photomask according to any one of claims 1 to 4, wherein the light-shielding film is formed in the part of the auxiliary pattern, or a complementary film having light-shielding properties different from those of the light-shielding film is formed in the part of the auxiliary pattern.

10. The photomask according to any one of claims 1 to 4, wherein by light transmitted through the auxiliary pattern, a light intensity distribution of the exposure light transmitted through the main pattern formed on a transfer body is changed, thereby increasing a depth of focus or an exposure latitude.

11. A method for manufacturing a display device, wherein The manufacturing method includes the following steps: exposing the photomask according to any one of claims 1 to 10 by an exposure device to transfer the transfer pattern to a transfer body. The photomask according to any one of claims 1 to 10.

Images