Photomask, method of manufacturing the photomask, and method of manufacturing a display device

Abstract

An object of the present invention is to provide a photomask, a method for manufacturing the photomask, and a method for manufacturing a display device, the photomask being capable of forming a resist pattern having an excellent upright profile on a transfer body. A photomask includes a transfer pattern including a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion on a transparent substrate. The light-transmitting portion is formed by exposing the transparent substrate. The semi-transmissive portion is formed by forming a transmission control film on the transparent substrate. The light-shielding portion has an edge portion and a laminated portion. The edge portion is disposed along an edge adjacent to the light-transmitting portion with a predetermined width D1 (μm) (where 0.5 ≤ D1), and is formed by forming a phase control film on the transparent substrate. The laminated portion is disposed in a region other than the edge portion, and is formed by laminating a phase control film and a transmission control film on the transparent substrate.

Description

Technical Field

[0001] The present invention relates to a photomask for manufacturing electronic devices, particularly suitable for manufacturing display devices, a method for manufacturing the same, and a method for manufacturing a display device using the same. Background Art

[0002] The following photomask is known, which has a transfer pattern including a light-shielding portion that shields exposure light, a light-transmitting portion that transmits exposure light, and a semi-transmissive portion that transmits a part of the exposure light, whereby the light intensity of the exposure light varies according to the region (hereinafter also referred to as a multi-gray-tone photomask). By performing exposure and development using this multi-gray-tone photomask, a resist pattern having at least three residual film thicknesses (including the case where the thickness is zero) can be formed on the transfer body. Therefore, when manufacturing electronic devices including display devices such as liquid crystal display devices and organic EL display devices, the number of photomasks used can be reduced and the production efficiency can be improved, so it is very useful.

[0003] Patent Document 1 describes a multi-gray-tone photomask that can obtain a resist pattern having a steep upright shape on the sidewall.

[0004] Specifically, Patent Document 1 describes the following multi-gray-tone photomask, which is formed as follows: a first semi-transmissive film and a second semi-transmissive film having respective predetermined light transmittances are formed on a transparent substrate, and respective predetermined patterning is performed, thereby forming a transfer pattern including a light-transmitting portion, a first semi-transmissive portion, and a second semi-transmissive portion having a portion adjacent to the first semi-transmissive portion. Patent Document 1 further describes that for the representative wavelength of light in the range of i-line to g-line, the phase difference between the second semi-transmissive portion and the light-transmitting portion is less than 90 degrees, for the representative wavelength, the phase difference between the first semi-transmissive portion and the second semi-transmissive portion is greater than 90 degrees, for the representative wavelength, the transmittance of the first semi-transmissive portion is less than 10%, and the transmittance of the second semi-transmissive portion is 20% or more.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2009-258250 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] According to Patent Document 1, when transferring a transfer pattern onto a resist film on a transfer target using an existing multi-tone photomask, diffraction of exposure light occurs at pattern boundaries such as the boundary between a semi-transmissive portion and a light-shielding portion. Therefore, the intensity distribution of the transmitted light becomes a gentle curve. That is, the rise and fall of the light intensity distribution curve become less steep. When transferring a resist pattern using such a multi-tone photomask, the vertical profile of the sidewall of the resist pattern formed on the resist film on the transfer target becomes gentle, and the sidewall of the resist pattern becomes conical. As a result, when processing a thin film using this resist pattern as a mask, it is difficult to control the processing line width. In the manufacturing process of a display panel or the like, the margin of processing conditions becomes narrow, leading to problems in mass production.

[0010] Therefore, in the invention described in Patent Document 1, as described above, a multi-tone photomask having two types of semi-transmissive portions is proposed. That is, in the multi-tone photomask described in Patent Document 1, for the representative wavelength of the exposure light, the phase difference between the second semi-transmissive portion and the transmissive portion is less than 90 degrees, the phase difference between the first semi-transmissive portion and the second semi-transmissive portion is greater than 90 degrees, and for the above-mentioned representative wavelength, the transmittance of the first semi-transmissive portion is less than 10%, and the transmittance of the second semi-transmissive portion is 20% or more.

[0011] By setting it in this way, at the boundary between the first semi-transmissive portion and the second semi-transmissive portion, the exposure light intensities cancel each other out, enhancing the contrast. In addition, the contrast is not enhanced between the transmissive portion and the second semi-transmissive portion. Therefore, the multi-tone photomask described in Patent Document 1 can prevent the appearance of dark lines at the boundary portion between the second semi-transmissive portion and the transmissive portion, and by the boundary between the first semi-transmissive portion and the second semi-transmissive portion, a shape with a steep vertical profile of the sidewall of the resist pattern formed on the transfer target can be obtained.

[0012] Figure 1 (a) shows the multi-tone photomask described in Patent Document 1 (refer to Figure 1Part of (a). In this multi - gray - scale photomask, the phase difference between the light - transmitting portion 11 and the second semi - light - transmitting portion 13 with respect to the exposure light is less than 90 degrees, preferably less than 60 degrees. And the phase difference between the first semi - light - transmitting portion 12 and the second semi - light - transmitting portion 13 with respect to the exposure light is greater than 90 degrees, preferably 180±30 degrees. With this setting, at the boundary between the first semi - light - transmitting portion 12 and the second semi - light - transmitting portion 13, the out - of - phase lights interfere with each other, obtaining a so - called phase - shift effect where their light intensities cancel each other out. Substantially, no cancellation of light intensity caused by this phase - shift effect occurs between the light - transmitting portion 11 and the second semi - light - transmitting portion 13. Therefore, the appearance of dark lines is prevented at the position on the transfer body corresponding to the boundary portion between the second semi - light - transmitting portion 13 and the light - transmitting portion 11, and at the position on the transfer body corresponding to the boundary portion between the first semi - light - transmitting portion 12 and the second semi - light - transmitting portion 13, the change in light intensity becomes steep. Therefore, it is considered that a resist pattern with a steep vertical profile on the sidewall can be obtained.

[0013] However, in the field of display devices where high - definition display performance is increasingly required, even using the multi - gray - scale photomask described in Patent Document 1 cannot be said to fully meet the requirements. The present inventors have found that there is still room for improvement in the dimensional accuracy and yield in the production of electronic devices such as display devices.

[0014] In Figure 1 In the multi - gray - scale photomask shown in (a), it is considered that the phase difference of the exposure light transmitted through both at the boundary between the first semi - light - transmitting portion 12 and the second semi - light - transmitting portion 13 is close to 180 degrees, so the transmitted lights interfere with each other, and it is regarded that a so - called phase - shift effect can be obtained. This has the effect of making the slope of the light intensity distribution curve on the transfer body steep, and to a certain extent, favorable effects can be expected. In addition, at the boundary between the first semi - light - transmitting portion 12 and the light - transmitting portion 11, the phase difference of the lights transmitted through both is also close to 180 degrees, and the transmitted lights interfere with each other, and it is considered that a phase - shift effect can also be obtained to a certain extent here.

[0015] On the other hand, in the portion far from the edge (near the center of the region) in the region of the first semi - light - transmitting portion 12, the above - mentioned phase - shift effect cannot be substantially obtained. And since the exposure light is transmitted at a prescribed transmittance (10% or less), the bottom of the light intensity distribution of this portion does not sufficiently decrease (insufficient light - shielding property). From this aspect, there may be an adverse situation that does not occur in the existing multi - gray - scale photomasks (disclosed in Patent Document 1 as Figure 10 and publicly available).

[0016] In addition, when the first semi-transmissive portion 12 is formed by laminating a second semi-transmissive film and a first semi-transmissive film, and the second semi-transmissive portion 13 is formed by a single layer film of the second semi-transmissive film, it is not easy to set the phase shift amounts of the first semi-transmissive portion 12 and the second semi-transmissive portion 13 to desired values. In addition, it is difficult to accurately control the phase difference at the edges of each region to 180 degrees. For example, if the phase difference between the first semi-transmissive portion (formed by lamination) 12 and the transmissive portion 11 is 180 degrees, the phase difference between the first semi-transmissive portion 12 and the second semi-transmissive portion 13 is a value smaller than that (the value after subtracting the phase shift amount of the second semi-transmissive film). Therefore, at the above-mentioned respective boundaries, the phase shift effect cannot be effectively generated.

[0017] In addition, when the first semi-transmissive portion 12 and the second semi-transmissive portion 13 are respectively formed by single layer films of the first semi-transmissive film and the second semi-transmissive film, there is a risk of alignment deviation during patterning at their adjacent portions, and there may be a gap between the two, or conversely, a dark line may be generated due to repetition.

[0018] Figure 1 (b) shows another photomask described in Patent Document 1. In this photomask, a light-shielding portion 14 formed of a light-shielding film is formed in a part of the portion that is the first semi-transmissive portion 12 of the above-mentioned Figure 1 (a).

[0019] It is considered that this photomask has improved the aspect of insufficient light-shielding property among the above-mentioned problems. However, in this case, no phase shift effect occurs between the light-shielding portion 14 and the transmissive portion 11, so the effect of improving the vertical profile of the resist pattern formed on the transfer body is reduced.

[0020] Therefore, one of the problems of the present invention is to provide a photomask capable of forming a resist pattern having an excellent vertical profile on a transfer body.

[0021] Another problem of the present invention is to provide a method for manufacturing the above-mentioned photomask and a method for manufacturing a display device.

[0022] Means for Solving the Problem

[0023] (First Mode)

[0024] The first mode of the present invention relates to a photomask having a transfer pattern including a transmissive portion, a light-shielding portion, and a semi-transmissive portion on a transparent substrate, wherein

[0025] the above-mentioned transfer pattern is formed by patterning a phase control film and a transmission control film formed on the above-mentioned transparent substrate respectively,

[0026] The above-described phase control film has a transmittance Tp (%) (where Tp ≥ 2) for light of the representative wavelength included in the exposure light of the above-described photomask and a phase shift amount of approximately 180 degrees.

[0027] The above-described transmittance control film has a transmittance Th (%) (where Th ≥ 20) for light of the above-described representative wavelength and a phase shift amount (degrees) (where ).

[0028] The above-described light-transmitting portion is formed by exposing the above-described transparent substrate.

[0029] The above-described semi-transmissive portion is formed by forming the above-described transmittance control film on the above-described transparent substrate.

[0030] The above-described light-shielding portion has an edge portion and a laminated portion.

[0031] The above-described edge portion is disposed along the edge adjacent to the above-described light-transmitting portion with a predetermined width D1 (μm) (where 0.5 ≤ D1), and it is formed by forming the above-described phase control film on the above-described transparent substrate.

[0032] The above-described laminated portion is disposed in a region other than the above-described edge portion, and it is formed by laminating the above-described phase control film and the above-described transmittance control film on the above-described transparent substrate.

[0033] (Second mode)

[0034] The second mode of the present invention relates to the photomask described in the first mode, wherein the above-described semi-transmissive portion has a portion adjacent to the above-described light-shielding portion, and the phase difference between the above-described semi-transmissive portion and the above-described light-shielding portion for light of the above-described representative wavelength is approximately 180 degrees.

[0035] (Third mode)

[0036] The third mode of the present invention relates to the photomask described in the first or second mode, wherein the above-described laminated portion is formed by directly or indirectly laminating the above-described transmittance control film on the above-described phase control film on the above-described transparent substrate.

[0037] (Fourth mode)

[0038] The fourth mode of the present invention relates to the photomask described in any one of the first to third modes, wherein the above-described phase control film and the above-described transmittance control film are made of materials having etching selectivity with respect to each other.

[0039] (Fifth mode)

[0040] The fifth mode of the present invention relates to the photomask described in any one of the first to fourth modes, wherein

[0041] The above lamination part includes a region where a light-shielding film is laminated in addition to the above phase control film and the above transmission control film.

[0042] The optical density OD of the above light-shielding film is 3 or more.

[0043] (Sixth mode)

[0044] The sixth mode of the present invention relates to the photomask described in the above fifth mode, wherein the above lamination part includes a region where the above phase control film, the above light-shielding film, and the above transmission control film are laminated in sequence on the above transparent substrate.

[0045] (Seventh mode)

[0046] The seventh mode of the present invention relates to the photomask described in the above sixth mode, wherein

[0047] The above light-shielding part further has a margin part that is disposed between the above lamination part and the above edge part and is formed with a specified width M (μm) (where 0 < M ≤ 0.8).

[0048] The above margin part is a part where the surface of the above light-shielding film is exposed and a part of the film thickness is lost from the surface of the light-shielding film.

[0049] (Eighth mode)

[0050] The eighth mode of the present invention relates to a method for manufacturing a photomask, which is a method for manufacturing a photomask having a transfer pattern including a light-transmitting part, a light-shielding part, and a semi-transmitting part on a transparent substrate.

[0051] The above light-transmitting part is formed by exposing the above transparent substrate. [[ID=!31]]

[0052] The above semi-transmitting part is formed by forming the above transmission control film on the above transparent substrate.

[0053] The above light-shielding part has an edge part and a lamination part.

[0054] The above edge part is disposed along the edge adjacent to the above light-transmitting part with a specified width D1 (μm) (where 0.5 ≤ D1), and it is formed by forming a phase control film on the above transparent substrate.

[0055] The above lamination part is disposed in a region other than the above edge part, and it is formed by laminating the above phase control film and the above transmission control film on the above transparent substrate.

[0056] In the above manufacturing method, the following steps are included:

[0057] A step of preparing a photomask blank having the above phase control film formed on the above transparent substrate;

[0058] a first patterning step of patterning the phase control film to form a phase control film pattern; and

[0059] In a second patterning step, a resist film is formed on the phase control film pattern and the transmission control film formed on the transparent substrate, and the resist film is drawn and developed to pattern the transmission control film using the resist pattern formed.

[0060] In the second patterning step,

[0061] The resist pattern has an opening expanded by D1 on each side of the adjacent light-shielding portion relative to the size of the region corresponding to the light-transmitting portion. The transmission control film is patterned using the resist pattern as a mask to form the edge portion.

[0062] (9th form)

[0063] A ninth aspect of the present invention relates to the method for manufacturing a photomask according to the eighth aspect, wherein:

[0064] The phase control film has a transmittance Tp (%) (where Tp ≥ 2) and a phase shift of approximately 180 degrees for light of a representative wavelength included in the exposure light of the photomask.

[0065] The transmission control film has a transmittance Th (%) (where Th ≥ 20) and a phase shift amount for the light of the representative wavelength. (degrees)(where ).

[0066] (10th method)

[0067] A tenth aspect of the present invention relates to the method for manufacturing a photomask according to the eighth or ninth aspect, wherein the phase control film and the transmittance control film are made of materials having mutual etching selectivity.

[0068] (11th form)

[0069] An eleventh aspect of the present invention relates to a method for manufacturing a photomask including a transfer pattern including a light-transmitting portion, a light-shielding portion, and a semi-light-transmitting portion on a transparent substrate.

[0070] The light-transmitting portion is formed by exposing the transparent substrate.

[0071] The semi-transparent portion is formed by forming the transmission control film on the transparent substrate.

[0072] The light shielding portion includes an edge portion, a laminated portion, and a margin portion.

[0073] The above-mentioned edge portion is arranged along the edge adjacent to the above-mentioned light-transmitting portion with a specified width D1 (μm) (where 0.5 ≤ D1), and it is formed by forming the above-mentioned phase control film on the above-mentioned transparent substrate.

[0074] The above-mentioned laminated portion is arranged in a region other than the above-mentioned edge portion, and it is formed by directly or indirectly laminating the above-mentioned transmission control film on the above-mentioned phase control film on the above-mentioned transparent substrate.

[0075] The above-mentioned margin portion is arranged between the above-mentioned edge portion and the above-mentioned laminated portion, and it has a specified width M (μm) (where M ≤ 0.8).

[0076] In the above-mentioned manufacturing method, the following steps are included:

[0077] A step of preparing a photomask blank in which the above-mentioned phase control film, a light-shielding film, and a first resist film are sequentially formed on the above-mentioned transparent substrate;

[0078] A step of performing drawing and development on the above-mentioned first resist film to form a first resist pattern;

[0079] A first patterning step, using the above-mentioned first resist pattern, patterning the above-mentioned light-shielding film, and then patterning the above-mentioned phase control film to form a phase control film pattern;

[0080] An etching step, using the above-mentioned first resist pattern, performing side etching on the above-mentioned light-shielding film to form a light-shielding film pattern; and

[0081] A second patterning step, forming a second resist film on the above-mentioned phase control film pattern, the above-mentioned light-shielding film pattern, and the above-mentioned transmission control film on the above-mentioned transparent substrate, performing drawing and development on the second resist film, and using the formed second resist pattern to pattern the above-mentioned transmission control film.

[0082] In the above-mentioned second patterning step,

[0083] The size of the above-mentioned second resist pattern with respect to the region corresponding to the above-mentioned light-transmitting portion has an opening expanded by an amount of (D1 + M) on each single side of the adjacent above-mentioned light-shielding portion side. By using the second resist pattern as a mask to pattern the above-mentioned transmission control film, the above-mentioned edge portion and the above-mentioned margin portion are formed.

[0084] (The 12th mode)

[0085] The 12th mode of the present invention relates to the manufacturing method of the photomask described in the above-mentioned 11th mode, wherein the above-mentioned phase control film and the above-mentioned transmission control film are made of materials having etching selectivity with respect to each other.

[0086] (The 13th mode)

[0087] The 13th aspect of the present invention relates to a method for manufacturing a photomask according to the 11th or 12th aspect described above, wherein the light-shielding film and the transmission control film are made of materials that can be etched using a common etchant for both.

[0088] (14th aspect)

[0089] The 14th aspect of the present invention relates to a method for manufacturing a photomask according to the 11th aspect or the 12th aspect described above, wherein

[0090] the phase control film has a transmittance Tp (%) (where Tp ≥ 2) and a phase shift amount of approximately 180 degrees with respect to the light of the representative wavelength included in the exposure light of the photomask,

[0091] the transmission control film has a transmittance Th (%) (where Th ≥ 20) and a phase shift amount (degrees) (where ).

[0092] (15th aspect)

[0093] The 15th aspect of the present invention relates to a method for manufacturing a photomask according to any one of the 11th to 14th aspects described above, wherein the margin portion is a portion where the surface of the light-shielding film laminated on the transmission control film is exposed and a part of the film thickness is lost from the surface of the light-shielding film.

[0094] (16th aspect)

[0095] The 16th aspect of the present invention relates to a method for manufacturing a display device, which includes the following steps:

[0096] a step of preparing the photomask according to any one of the 1st to 7th aspects described above, or a photomask obtained by using the manufacturing method according to any one of the 8th to 15th aspects described above; and

[0097] a step of exposing the photomask using an exposure device. [[ID=e35]]

[0098] Effects of the Invention

[0099] According to the present invention, it is possible to provide a photomask useful as a multi-tone photomask having a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion, and the photomask can form a resist pattern having an excellent upright profile on a transfer body by transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] Figure 1 It is an explanatory diagram illustrating a main part of a conventional multi-tone photomask. (a) is a diagram showing one configuration example, and (b) is a diagram showing another configuration example.

[0101] Figure 2 It is an explanatory diagram showing a transfer pattern (Reference Example 1) of a photomask used in simulation. (a) is a top view, (b) is a longitudinal sectional view thereof, and (c) is a longitudinal sectional view of another configuration example.

[0102] Figure 3 It is an explanatory diagram showing a transfer pattern (Reference Example 2) of another type of photomask used in simulation.

[0103] Figure 4 It is an explanatory diagram showing a photomask according to the first embodiment of the present invention. (a) is a top view, and (b) is a diagram showing a longitudinal section of the portion indicated by the dotted line in (a).

[0104] Figure 5 It is an explanatory diagram showing the light intensity distribution obtained on the transfer body by optical simulation. (a) is a diagram showing the light intensity distribution in the case of Reference Example 1, (b) is a diagram showing the light intensity distribution in the case of Reference Example 2, and (c) is a diagram showing the light intensity distribution in the case of the photomask according to the first embodiment of the present invention.

[0105] Figure 6 It is an explanatory diagram showing a method for manufacturing a photomask according to the first embodiment of the present invention. (a) to (h) are diagrams showing the cross-sections of the mask in each process of the manufacturing method.

[0106] Figure 7 It is an explanatory diagram showing a photomask according to the second embodiment of the present invention. (a) is a top view, and (b) is a diagram showing a longitudinal section of the portion indicated by the dotted line in (a).

[0107] Figure 8 It is an explanatory diagram (one) showing a method for manufacturing a photomask according to the second embodiment of the present invention. (a) to (e) are diagrams showing the cross-sections of the mask in each process of the manufacturing method.

[0108] Figure 9 It is followed by Figure 8 (e) and is an explanatory diagram (two) showing a method for manufacturing a photomask according to the second embodiment of the present invention. (f) to (j) are diagrams showing the cross-sections of the mask in each process of the manufacturing method.

[0109] Figure 10 It is an explanatory diagram showing a modified example of the method for manufacturing a photomask according to the second embodiment of the present invention. (i') and (j') are diagrams showing the cross-sections of the mask in the processes performed instead of Figure 9 (i) and (j). Detailed Embodiments

[0110] Hereinafter, embodiments of the photomask, the method for manufacturing the photomask, and the method for manufacturing a display device according to the present invention will be described.

[0111] The present inventors examined the problems of the multi-gray-tone photomask described in the above-mentioned Patent Document 1 and conducted the following transfer simulation. In addition to the photomask of the first embodiment of the present invention (hereinafter also referred to as photomask 1) and the photomask of the second embodiment (hereinafter also referred to as photomask 2), transfer simulations were also conducted on the photomasks of Reference Example 1 and Reference Example 2.

[0112] <Photomask of Reference Example 1>

[0113] Figure 2 The transfer pattern of the photomask used in the simulation is shown (Reference Example 1). Figure 2 (a) is a top view, Figure 2 (b) is its longitudinal section. This transfer pattern has a light-transmitting portion 101, a light-shielding portion 102, and a semi-light-transmitting portion 103, and is formed by patterning a phase control film 105 and a transmission control film 106 on a transparent substrate 104, respectively.

[0114] The light-transmitting portion 101 is formed by exposing the transparent substrate 104, and the light-shielding portion 102 is formed by forming at least the phase control film 105 on the transparent substrate 104. In addition, the semi-light-transmitting portion 103 is formed by forming the transmission control film 106 on the transparent substrate 104. When the photomask of the present invention is used for manufacturing a display device, a substrate having a quadrilateral shape with one side of the main surface being 300 mm or more (for example, one side being 300 to 2000 mm) can be applied.

[0115] This transfer pattern can be applied to, for example, a photomask for manufacturing a TFT (Thin Film Transistor) for a display device. Here, the light-shielding portions 102 are arranged adjacent to the semi-light-transmitting portion 103 and sandwich the semi-light-transmitting portion 103 from both sides.

[0116] Here, when the photomask is exposed, a light source having exposure light in a wavelength range including i-line to g-line is used. The transmittance Tr1 of the transmission control film 106 for a representative wavelength (for example, h-line) in this range is 40% (assuming the transmittance of the transparent substrate 104 is 100%), and the phase shift amount is 10 degrees. On the other hand, the transmittance Tr2 of the phase control film 105 for the above-mentioned representative wavelength is 5%, and the phase shift amount is 180 degrees.

[0117] It should be noted that, regarding Figure 2 the photomask shown in (a), in addition to Figure 2 the cross-sectional structure shown in (b), by changing the film formation order and patterning process of the phase control film 105 and the transmission control film 106, it can also be configured as Figure 2The cross-sectional structure shown in (c).

[0118] By optical simulation, the light intensity distribution obtained on the transfer body when exposing the photomask of (a) using the above light source is obtained. Figure 2 The light intensity distribution obtained on the transfer body when exposing the photomask of (a) is shown. Figure 2 The light intensity distribution at the position corresponding to the dashed line L1 in (a) is shown in Figure 5 (a). The bottom of the light intensity distribution at the position corresponding to the light-shielding portion 102 (the portion (A) shown in Figure 5 (a)) floats up, and it can be seen that the light-shielding property is insufficient at positions far from the edge of the light-shielding portion 102.

[0119] <Photomask of Reference Example 2>

[0120] Figure 3 Shows the transfer pattern of another type of photomask used in the simulation (Reference Example 2). Figure 3 The cross-sectional view of can be regarded as the same as Figure 2 (b) or Figure 2 (c). However, here, instead of the phase control film 105, a light-shielding film 107 having an OD (optical density) of 3 or more with respect to the exposure light is used.

[0121] Similar to the exposure of the photomask of Figure 2 (a), the photomask shown is exposed, and the light intensity distribution formed on the transfer body at this time is shown in Figure 3 (b). Here, the light intensity distribution on the transfer body corresponding to the position of the dashed line L2 shown in Figure 5 is also shown. Figure 3 Shown is the light intensity distribution on the transfer body corresponding to the position of the dashed line L2 shown.

[0122] Figure 5 (b), the light-shielding portion 102 has sufficient light-shielding property, and no floating of the bottom is observed. However, compared with the case of Figure 5 (a), the slopes on both sides of the bottom are gentle (assuming the inclination angles of Figure 5 (a) and Figure 5 (b) are θ1 and θ2 respectively, then θ1>θ2). In this case, when exposing and developing the resist film formed on the transfer body using the photomask, the cross-sectional shape of the side wall of the resist pattern formed has a tendency to have a larger inclination, and in the subsequent etching process using this resist pattern as an etching mask, the accuracy of CD (pattern width) control tends to become insufficient.

[0123] <Photomask 1 of the First Embodiment>

[0124] Figure 4 (a) shows the photomask 1 of the first embodiment of the present invention. Figure 4 (b) shows Figure 4The longitudinal cross-section of the chain-dotted portion of (a).

[0125] The photomask is formed by patterning a phase control film 4 and a transmission control film 5 on a transparent substrate 3, and has a light-transmitting portion 6, a light-shielding portion 7, and a semi-transmissive portion 8. Similar to the photomask of Reference Example 1, it includes a light-shielding portion 7 that is adjacent to the semi-transmissive portion 8 and sandwiches the semi-transmissive portion 8 from both sides.

[0126] The transparent substrate 3 is a plate made of a transparent material such as quartz, and its main surface can be polished to be flat and smooth.

[0127] The transmittance Tp (%) of the phase control film 4 for the light of the representative wavelength satisfies 2 ≤ Tp, and the phase shift amount is approximately 180 degrees. Here, approximately 180 degrees means a range of 180 ± 20 degrees, that is The transmittance Tp is preferably 2 ≤ Tp < 15, more preferably 3 < Tp < 10. When the value of the transmittance Tp is too small, the phase shift effect cannot be obtained sufficiently. On the other hand, when the transmittance Tp is too large, there is a risk that the light-shielding property at the laminated portion described later becomes insufficient.

[0128] The transmittance Th (%) of the transmission control film 5 for the light of the representative wavelength satisfies Th ≥ 20, preferably 20 ≥ Th < 60. In addition, the phase shift amount (corresponding to (0) is an example) satisfies degrees, preferably degrees, more preferably degrees.

[0129] In the transfer pattern of the photomask 1, as shown in Figure 4 (a), the light-transmitting portion 6 is formed by exposing the surface of the transparent substrate 3.

[0130] The light-shielding portion 7 is a region where at least the phase control film 4 is formed on the transparent substrate 3. Among them, different from the photomask of Reference Example 1, the light-shielding portion 7 has an edge portion 7a and a laminated portion 7b. That is, the light-shielding portion 7 has an edge portion 7a, which is a region along the boundary between the light-shielding portion 7 and the adjacent light-transmitting portion 6 (that is, the edge of the light-shielding portion 7 adjacent to the light-transmitting portion 6) and has a specified width D1 (μm), and it is formed by forming only the phase control film 4 on the transparent substrate 3. In addition, the region other than the edge portion 7a in the light-shielding portion 7 becomes the laminated portion 7b formed by laminating the phase control film 4 and the transmission control film 5. Figure 4 (b), the transmission control film 5 is directly laminated on the phase control film 4, but it can also be indirectly laminated on the phase control film 4 with other films in between.

[0131] Therefore, the edge portion 7a and the light-transmitting portion 6 are adjacent to each other, and the phase difference for the representative wavelength of the exposure light is (i.e., approximately 180 degrees). Due to this phase difference, the transmitted lights passing through the edge portion 7a and the light-transmitting portion 6 interfere with each other, obtaining a so-called phase shift effect in which the light intensities cancel each other out. On the transfer body, the contour of the light intensity distribution at this position is improved (the inclination of the light intensity distribution is suppressed).

[0132] On the other hand, in the light-shielding portion 7, the portion other than the edge portion 7a (the portion far from the edge) forms a laminated structure of the phase control film 4 and the transmission control film 5. Therefore, the transmittance Tr6 (%) of the exposure light is suppressed to be low. The transmittance Tr6 of the laminated portion 7b is preferably Tr6 < 5, and more preferably Tr6 < 3.

[0133] The width D1 (μm) of the edge portion 7a can be set, for example, as 0.5 ≤ D1 < 5.0. When the width D1 is too small, there is a risk that the phase shift effect described later cannot be fully exerted at the boundary between the edge portion 7a and the light-transmitting portion 6. On the other hand, when the width D1 is too large, the light-shielding property of the light-shielding portion 7 is insufficient, and in the Figure 5 light intensity distribution described above, there is a risk that the value at the bottom increases. The width D1 is more preferably set as 0.5 ≤ D1 ≤ 2.0.

[0134] It should be noted that, as shown in Figure 4 (a), when the light-shielding portion 7 is adjacent to the light-transmitting portion 6 and is clamped by the light-transmitting portion 6 from both sides ( Figure 4 in (a), it is the up-down direction), the width D1 needs to be less than 1 / 2 of the width W of the light-shielding portion 7. In addition, from the viewpoint of ensuring the light-shielding property of the light-shielding portion 7, the width D1 is preferably 1 / 4 or less with respect to the width W (μm) of the light-shielding portion 7.

[0135] The semi-transmissive portion 8 is formed by forming only the transmission control film 5 on the transparent substrate 3. The phase shift amount (degrees) of the transmission control film 5 for the above representative wavelength of light is as described above and is more preferably That is, although the semi-transmissive portion 8 is adjacent to the light-transmitting portion 6, since the phase difference of the light for the above representative wavelength at its boundary is less than 90 degrees, no dark line is generated on the transfer body.

[0136] The semi-transmissive portion 8 has a portion adjacent to the light-shielding portion 7, but due to the phase difference of the transmitted light (for the above representative wavelength of light) at its boundary being (i.e., approximately 180 degrees), thus, the same phase shift effect as described above can also be obtained in this portion, and the benefit that the light intensity distribution becomes steeper can be obtained.

[0137] As shown in Figure 4As shown in (a), here, the width W of the light-shielding portion 7 and the width V (μm) of the semi-transmissive portion 8 satisfy W < V.

[0138] In addition, the overlapping width D2 (μm) of the portion of the transmission control film 5 with width V and the phase control film 4 is preferably 0.5 ≤ D2 < 2. When it is in this range, in the manufacturing method of the photomask 1 described later, the alignment error between the phase control film 4 and the transmission control film 5 can be absorbed, and no gap between the films will be generated.

[0139] Here, the width W and the width V are the widths in the direction perpendicular to the arrangement direction of the semi-transmissive portion 8 and the light-shielding portions 7 that sandwich the semi-transmissive portion 8 from both sides.

[0140] In the resist pattern to be formed on the transfer body by exposing the photomask 1 configured as above, the cross-sectional shape of its sidewall can be made sharper, and the dimensional accuracy and yield of the electronic device to be obtained using this photomask can be improved.

[0141] The transfer pattern in the photomask 1 is formed by disposing a separately patterned phase control film 4 and a transmission control film on a transparent substrate 3. Optionally, other films or film patterns may be formed on the transparent substrate 3.

[0142] Both the phase control film 4 and the transmission control film 5 are preferably made of materials that can be wet-etched.

[0143] The material of the phase control film 4 can be Cr or its compound (oxide, nitride, carbide, oxynitride, or carbonitride), or can be a metal compound containing Mo, W, Ta, or Ti. As the metal compound, it can be a metal silicide or the above compound of the silicide. In addition, it can be composed of a material containing any one of Zr, Nb, Hf, Ta, Mo, Ti, and Si, or a material containing an oxide, nitride, oxynitride, carbide, or carbonitride of these materials, and further can be the above compound of Si.

[0144] The material of the transmission control film 5 can be Cr or its compound (oxide, nitride, carbide, oxynitride, or carbonitride), or can be a metal compound containing Mo, W, Ta, or Ti. As the metal compound, it can be a metal silicide or the above compound of the silicide.

[0145] The phase control film 4 and the transmission control film 5 are preferably made of materials having etching selectivity with respect to each other. That is, it is preferred that the transmission control film 5 is resistant to the etchant for the phase control film 4 and the phase control film 4 is resistant to the etchant for the transmission control film 5.

[0146] The photomask 1 can be used as a multi-tone photomask. That is, it can be used as a photomask for forming a resist pattern having a plurality of regions with different remaining film thicknesses of the resist on the transfer body. Here, the resist can be a positive or negative photoresist.

[0147] This multi-tone photomask, for example, when manufacturing a display device, has the effect of reducing the number of photomask sheets required compared to the case of using only a binary mask, and is a functional photomask.

[0148] Among them, in addition to the resist pattern used as an etching mask during the manufacturing process of electronic devices and then removed, the above-mentioned resist pattern also includes a resist pattern remaining in an electronic device such as a display device as a three-dimensional structure composed of a photosensitive material.

[0149] Using this photomask 1, the same optical simulation as above is performed, and the result is as Figure 5 shown in (c). The portion (B) corresponding to the bottom of the light intensity distribution is reduced compared to the case of Figure 5 (a), and in addition, the inclination on both sides of the bottom is suppressed, and the inclination angle (θ3) is the same as the inclination angle θ1 of Figure 5 (a).

[0150] Therefore, it can be known that when using the photomask 1 and performing exposure with an FPD (Flat Panel Display) exposure apparatus, the shape of the resist pattern formed on the transfer body becomes good.

[0151] <Manufacturing method of photomask 1>

[0152] Refer to Figure 6 to describe an example of the manufacturing method of the photomask 1. `

[0153] (a) Prepare a resist-coated photomask blank having a phase control film 4 formed on the main surface of a transparent substrate 3 and further having a first resist film 21 formed thereon. The first resist film 21 is a positive photoresist. The film formation of the phase control film 4 can use a known method such as sputtering. The same applies to the transmission control film 5 and the light-shielding film 9 described later.

[0154] (b) Using a drawing device, the first resist film 21 is drawn using pattern data based on the device pattern to be obtained, and developed, thereby obtaining a first resist pattern 21'. Here, a laser drawing device can be used.

[0155] (c) Using the first resist pattern 21' as an etching mask, the phase control film 4 is wet-etched to form a phase control film pattern 4' (defining the region of the light-shielding portion 7). When the phase control film 4 contains a metal silicide (such as MoSi), a fluorine-based etchant can be used.

[0156] (d) After removing the first resist pattern 21', a transmission control film 5 is formed over the entire main surface of the transparent substrate 3. The material of the transmission control film 5 may include a Cr compound to ensure the etching selectivity between it and the phase control film 4.

[0157] (e) A second resist film 22 is formed on the transmission control film 5.

[0158] (f) The second resist film 22 is drawn and developed to form a second resist pattern 22'. The second resist pattern 22' covers the region that becomes the semi-transmissive portion 8 and the region in the region that becomes the light-shielding portion 7 except for the region that becomes the edge portion 7a.

[0159] (g) Using the second resist pattern 22' as an etching mask, the exposed transmission control film 5 is etched to form a transmission control film pattern 5'. When the transmission control film 5 is a Cr-based film, a known etching agent for Cr can be used. Through this etching, the edge portion 7a and the semi-transmissive portion 8 are formed.

[0160] (h) The second resist pattern 22' is removed to complete the photomask 1.

[0161] In the above manufacturing method, in any one of the steps of forming the phase control film pattern 4' and the step of forming the transmission control film pattern 5', a single film is respectively used as the etching object. That is, a step of continuously etching two or more stacked layers using the same etching agent is not applied. Therefore, each etching can be completed in a short time, and the progress of side etching can be suppressed. As a result, the deviation of CD (Critical Dimension, pattern width) within the photomask surface can be suppressed, and excellent CD accuracy can be obtained.

[0162] It should be noted that when there is an alignment deviation between the drawing in the step (b) and the drawing in the step (f), the width of the edge portion 7a tends to be difficult to be uniform within the surface. Regarding this point, it will be described below in the description of the photomask 2.

[0163] <Photomask 2 of the Second Embodiment>

[0164] Figure 7 (a) shows the photomask 2 of the second embodiment of the present invention. Figure 7 (b) shows Figure 7 the longitudinal cross-section of the dotted line portion in (a).

[0165] The difference between the photomask 2 and the photomask 1 is that, in addition to the phase control film 4 and the transmission control film 5, a light-shielding film 9 is also used.

[0166] The photomask 2 is formed by patterning a phase control film 4, a light-shielding film 9, and a transmission control film 5 on a transparent substrate 3, and has a light-transmitting portion 6, a light-shielding portion 7, and a semi-transmissive portion 8. Similarly to the photomask 1, it includes light-shielding portions 7 that are adjacent to the semi-transmissive portion 8 and sandwich the semi-transmissive portion 8 from both sides.

[0167] The transparent substrate 3 can be the same transparent substrate as that of the photomask 1.

[0168] The phase control film 4 can also be the same phase control film as that of the photomask 1. That is, for light of the above representative wavelength, the transmittance Tp (%) satisfies Tp ≥ 2, preferably 2 ≤ Tp < 15. The transmittance Tp is more preferably 3 < Tp < 10. In addition, the phase shift amount is approximately 180 degrees. Here, approximately 180 degrees means a range of 180 ± 20 degrees, that is

[0169] The light-shielding film 9 substantially blocks the exposure light (preferably the optical density OD ≥ 3). The light-shielding film 9 may be provided with a reflection control layer (not shown) for controlling the reflection of light on its front side and / or back side.

[0170] The transmittance Th (%) of the transmission control film 5 for light of the above representative wavelength satisfies Th ≥ 20, preferably 20 ≤ Th < 60. In addition, the phase shift amount is degrees, more preferably degrees.

[0171] Similarly to the photomask 1, in the transfer pattern of the photomask 2, as Figure 7 (a) shows, the light-transmitting portion 6 is formed by exposing the surface of the transparent substrate 3.

[0172] The light-shielding portion 7 is a region where at least the phase control film 4 is formed on the transparent substrate 3. However, different from the photomask 1, the light-shielding portion 7 has an edge portion 7a, a margin portion 7c, and a laminated portion 7b.

[0173] That is, the light-shielding portion 7 is a region along the boundary between the light-shielding portion 7 and the adjacent light-transmitting portion 6 (i.e., the edge of the light-shielding portion 7 adjacent to the light-transmitting portion 6) and having a specified width D1 (μm), and it has an edge portion 7a where only the phase control film 4 is formed on the transparent substrate 3. The size of the width D1 is the same as that of the photomask 1. [[ID=3�]]

[0174] In addition, the light-shielding portion 7 has a margin portion 7c with a specified width M (μm) adjacent to the edge portion 7a (adjacent on the side opposite to the boundary adjacent to the light-transmitting portion 6). The margin portion 7c is formed by laminating the phase control film 4 and the light-shielding film 9. The size of M is not particularly limited as long as (W / 2 - D1) > M. Among them, it is preferably 0 < M ≤ 0.8. This will be further described below.

[0175] Here too, the portion where the transmission control film 5 is directly or indirectly laminated on the phase control film 4 is the lamination portion 7b. Figure 7 Among them, the lamination portion 7b is formed by laminating the transmission control film 5 on the phase control film 4 with the light-shielding film 9 interposed therebetween. In the light-shielding portion 7, the margin portion 7c and the lamination portion 7b are arranged in the region other than the edge portion 7a.

[0176] In such a photomask 2, similarly to the photomask 1, the edge portion 7a and the light-transmitting portion 6 are adjacent to each other, and the phase difference with respect to the representative wavelength of the exposure light is (i.e., approximately 180 degrees). Due to this phase difference, the transmitted lights respectively transmitted through the edge portion 7a and the light-transmitting portion 6 interfere with each other, obtaining a so-called phase shift effect in which the light intensities cancel each other out. On the transfer body, the contour of the light intensity distribution at this position is improved (the inclination of the light intensity distribution is suppressed).

[0177] On the other hand, the portion other than the edge portion 7a in the light-shielding portion 7 (the portion far from the edge) includes a laminated structure of the phase control film 4 and the transmission control film 5. Furthermore, the light-shielding film 9 is laminated in the region other than the edge portion 7a and the margin portion 7c (also referred to as the central region). Therefore, the light-shielding property is excellent, and substantially no influence caused by the transmission of the exposure light is generated.

[0178] The width D1 (μm) of the edge portion 7a can be set to 0.5 ≤ D1 < 5.0 in the same manner as in the case of the photomask 1. More preferably, it can be set to 0.5 ≤ D1 ≤ 2.0.

[0179] The semi-transmissive portion 8 is formed by forming only the transmission control film 5 on the transparent substrate 3. The phase shift amount of the transmission control film 5 with respect to the light of the above-mentioned representative wavelength (degrees) is as described above More preferably That is, although the semi-transmissive portion 8 is adjacent to the light-transmitting portion 6, due to the phase difference at its boundary being less than 90 degrees, no dark line is generated on the transfer body.

[0180] The semi-transmissive portion 8 has a portion adjacent to the light-shielding portion 7, but due to the transmitted light at its boundary (for the light of the above-mentioned representative wavelength) being (i.e., approximately 180 degrees), so that in this part, the same phase shift effect as described above can be obtained, and the benefit of a steeper light intensity distribution can be achieved.

[0181] Figure 7 In (a), the overlapping width D2 (μm) of the portion of the transmission control film 5 with width V and the phase control film 4 is the same as that of the above-described photomask 1.

[0182] In the resist pattern to be formed on the transfer body by exposing the photomask 2 configured as above, the cross-sectional shape of its sidewall can also be made sharper, and the dimensional accuracy and yield of the electronic device to be obtained using this photomask can be improved.

[0183] The transfer pattern in the photomask 2 is formed by disposing the patterned phase control film 4, light-shielding film 9, and transmission control film 5 on the transparent substrate 3, respectively. Other films or film patterns may also be additionally formed on the transparent substrate 3.

[0184] The phase control film 4, light-shielding film 9, and transmission control film 5 are all preferably made of materials that can be wet-etched.

[0185] The material of the phase control film 4 can be selected from the same materials as the candidate materials for the above-described photomask 1. Similarly for the transmission control film 5.

[0186] In addition, the phase control film 4 and the transmission control film 5 are preferably made of materials that have etching selectivity with respect to each other. That is, it is preferable that the transmission control film 5 is resistant to the etchant for the phase control film 4, and the phase control film 4 is resistant to the etchant for the transmission control film 5.

[0187] The light-shielding film 9 can have etching selectivity with respect to one or both of the materials of the phase control film 4 and the transmission control film 5. Among them, the light-shielding film 9 can have common etching characteristics with the transmission control film 5. In the manufacturing method 2 of the photomask 2 described later, the case where both the light-shielding film 9 and the transmission control film 5 contain Cr and can be etched using a common etchant is described.

[0188] The photomask 2 can be used as a multi-tone photomask in the same manner as the photomask 1. That is, it is a photomask for forming a resist pattern having a plurality of regions with different remaining film thicknesses of the resist on the transfer body. Here, the resist can be a positive or negative photoresist.

[0189] Among them, the above-described resist pattern includes, in addition to the resist pattern used as an etching mask during the manufacturing process of the electronic device and then removed, a resist pattern that remains as a three-dimensional structure made of a photosensitive material in an electronic device such as a display device.

[0190] Similar to the photomask 1, the photomask 2 can suppress the inclination of the cross-section of the sidewall of the resist pattern formed on the transfer body during exposure using an FPD exposure apparatus. In addition, the light-shielding property brought by the light-shielding portion 7 is higher.

[0191] <Manufacturing method of photomask 2>

[0192] Refer to Figure 8 and Figure 9 A manufacturing method example of the photomask 2 will be described.

[0193] (a) Prepare a resist-coated photomask blank in which a phase control film 4 and a light-shielding film 9 are sequentially formed on the main surface of a transparent substrate 3, and further a first resist film 21 is formed. The first resist film 21 is a positive-type photoresist.

[0194] (b) Using a drawing apparatus, the first resist film 21 is drawn using pattern data based on the device pattern to be obtained, and developed to obtain a first resist pattern 21'. Here, a laser drawing apparatus can be applied.

[0195] (c) The light-shielding film 9 is wet-etched using the first resist pattern 21' as an etching mask to form a light-shielding film pattern 9'. Here, the light-shielding film 9 is made of a material containing Cr, and a Cr etchant (such as ammonium cerium nitrate) is used. Then, using this light-shielding film pattern 9' as an etching mask, the phase control film 4 is wet-etched (to define the region of the light-shielding portion 7). Here, the phase control film 4 contains a metal silicide (such as MoSi), and a fluorine-based etchant is used during etching.

[0196] (d) The Cr etchant is applied again, and the first resist pattern 21' and the phase control film pattern 4' are used as etching masks to perform side etching on the light-shielding film 9. The side etching width is set to D1 (μm), and the etching is stopped.

[0197] (e) Remove the first resist pattern 21'.

[0198] (f) A transmission control film 5 is formed over the entire surface of the main surface of the transparent substrate 3. The material of the transmission control film 5 may contain a Cr compound. The transmission control film 5 and the light-shielding film 9 can be etched using the same etchant. Among them, for this etchant, the time required to etch away the film thickness is preferably in the range of (time required for the light-shielding film 9: time required for the transmission control film 5) of (5:1) to (20:1). The time required for this etching is determined by the film material and the film thickness.

[0199] (g) A second resist film 22 is formed on the transmission control film 5.

[0200] (h) The second resist film 22 is drawn and developed to form a second resist pattern 22'. The second resist pattern 22' covers the region that becomes the semi-transmissive portion 8 and the region that becomes the light-shielding portion 7 except for the regions that become the edge portion 7a and the margin portion 7c. That is, the second resist pattern 22' has an opening expanded by an amount of (D1 + M) on each single side on the side of the adjacent light-shielding portion 7 with respect to the size of the region corresponding to the light-transmissive portion 6. Therefore, as described later, by patterning the transmission control film 5 using the second resist pattern 22' as a mask, the edge portion 7a and the margin portion 7b are formed.

[0201] (i) Using the second resist pattern 22' as an etching mask, the exposed transmission control film 5 is etched to form a transmission control film pattern 5'. The etching is stopped when the transmission control film 5 is etched away. It should be noted that after the etching of the transmission control film 5 is completed, the light-shielding film 9 is exposed in the region that becomes the margin portion 7c. Since the light-shielding film 9 and the transmission control film 5 have common etching characteristics, the surface of the light-shielding film 9 may be damaged and a part of the film thickness may be etched away. That is, the film thickness of the light-shielding film 9 remaining in the region that becomes the margin portion 7c is slightly smaller than the film thickness of the light-shielding film 9 at the light-shielding portion 7 (the region except for the edge portion 7a and the margin portion 7c, the central region). In other words, the margin portion 7c is the portion where the surface of the light-shielding film 9 is exposed and a part of the film thickness is lost from the surface of the light-shielding film 9.

[0202] When the light-shielding film 9 has an antireflection layer on the surface side, the antireflection layer may be partially or completely removed. However, it does not substantially affect the light-shielding property of the light-shielding portion 9. In addition, even if the reflection characteristics change in the margin portion, since the patterning process that requires the antireflection function has been completed, there are no disadvantages.

[0203] (j) The second resist pattern 22' is removed to complete the photomask 2.

[0204] In the above manufacturing method, there is only one drawing process in the process of forming the phase control film pattern 4' and the light-shielding film pattern 9'. That is, using the first resist pattern 21' formed by the drawing in the process of (b), the phase control film pattern 4' is patterned, and further, by side etching, the light-shielding film pattern 9' is patterned. Therefore, the width D1 of the edge portion 7a of the obtained photomask 2 is the same as the side etching width, and a uniform width is achieved in the plane. In other words, the manufacturing method of the photomask 1 can eliminate the influence of the alignment deviation that may occur between the two drawings, and the width D1 of the edge portion 7a in the plane of the photomask does not deviate. And when the width of the edge portion 7a is uniform in the plane, the phase shift effect obtained from this part, that is, the improvement effect of the light intensity distribution, is uniform in the plane. Therefore, excellent effects such as improved CD accuracy and improved yield can be obtained in the electronic device to be obtained using the photomask 2.

[0205] It should be noted that when the width M (μm) of the margin portion 7c is too large, there is a risk that the region of the above-mentioned damage on the surface of the light-shielding film 9 becomes wider. Considering this point, the preferred range of the width M of the margin portion 7c is 0 < M ≤ 0.8.

[0206] In the above manufacturing method, in any one of the process of forming the phase control film pattern 4', the process of forming the light-shielding film pattern 9', and the process of forming the transmission control film pattern 5', a single film is respectively used as the etching object. That is, a process of continuously etching two or more layers using the same etching agent is not applied, so each etching can be completed in a short time. As a result, the progress of side etching can be suppressed, so that the deviation of CD in the plane of the photomask can be suppressed, and excellent CD accuracy can be obtained.

[0207] In addition, the light-shielding portion 7 of the photomask 2 is laminated in three layers in the region other than the edge portion 7a and the margin portion 7c (also referred to as the central region), so its light-shielding property is extremely excellent, and preferably it can be OD4 or more.

[0208] Figure 10 The process of manufacturing the photomask 2' by a modified example of the manufacturing method of the photomask 2 is shown. Here, after Figure 9 (h), refer to Figure 10 (i') and (j').

[0209] (i') Using the second resist pattern 22' as an etching mask, the exposed transmission control film 5 is etched to form a transmission control film pattern 5'. Further continue the etching to etch the exposed part of the light-shielding film 9. After the above etching is completed, the phase control film 4 with a width D3 is exposed to form the edge portion 7a.

[0210] (j') Remove the second resist pattern 22' to complete the photomask 2'.

[0211] In the photomask 2', the width D3 of the edge portion 7a is also uniform within the surface. Therefore, the phase shift effect obtained by this portion, that is, the effect of improving the light intensity distribution, is uniform within the surface. As a result, the CD accuracy and yield of electronic devices obtained using the photomask 2' are improved.

[0212] In the photomask 2 ′, the width D3 (μm) of the edge portion 7 a can be set to 0.5≤D3<5.0.

[0213] <Method for Manufacturing Display Device>

[0214] The photomask of the present invention is suitable for use in display device manufacturing, which applies to both photomask 1 and photomasks 2 and 2'. The exposure apparatus used for display device manufacturing can be an exposure apparatus employing a projection exposure method (e.g., a numerical aperture of 0.08 to 0.15) for FPDs (Flat Panel Displays). The light source can include any of the i-line, h-line, and g-line wavelengths, and light containing two or more wavelengths or wavelength ranges can be effectively used.

[0215] Specifically, a display device can be manufactured by preparing either photomask 1 or photomasks 2 or 2'; and exposing photomask 1 or photomasks 2 or 2' using an exposure device. Thus, the photomask of the present invention can be suitably used, for example, in the manufacture of TFT (thin-film transistor) substrates for display devices (liquid crystal display devices, organic EL display devices). It should be noted that, in this specification, a display device includes the electronic components that constitute the display device.

[0216] <Modification>

[0217] While the embodiments of the present invention have been specifically described above, the technical scope of the present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit and scope of the present invention.

[0218] The photomask of the present invention is suitable for use in display device manufacturing, but its use is not limited. That is, the use, structure, and production method of the photomask of the present invention are not limited to the above examples as long as the effects of the present invention are not impaired.

[0219] Furthermore, additional optical films or functional films may be used in the photomask of the present invention within a range that does not impair the effects of the present invention.

[0220] Explanation of symbols

[0221] 3…Transparent substrate, 4…Phase control film, 4’…Phase control film pattern, 5…Transmission control film, 5’…Transmission control film pattern, 6…Light transmissive portion, 7…Light shielding portion, 7a…Edge portion, 7b…Laminated portion, 7c…Margin portion, 8…Semi-transmissive portion, 9…Light shielding film, 9’…Light shielding film pattern, 21…First resist film, 21’…First resist pattern, 22…Second resist film, 22’…Second resist pattern.

Claims

1. A photomask, which is a photomask having a transfer pattern including a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion on a transparent substrate, wherein, the transfer pattern is formed by patterning a phase control film and a transmission control film formed on the transparent substrate respectively, the phase control film has a transmittance Tp and a phase shift amount φ4 for light of a representative wavelength included in the exposure light of the photomask, where Tp≥2, the unit of the transmittance Tp is %, 160≤φ4≤200, and the unit of the phase shift amount φ4 is degrees, the transmission control film has a transmittance Th and a phase shift amount φh for the light of the representative wavelength, where Th≥20, φh<90, the unit of the transmittance Th is %, and the unit of the phase shift amount φh is degrees, the light-transmitting portion is formed by exposing the transparent substrate, the semi-transmissive portion is formed by forming the transmission control film on the transparent substrate, the light-shielding portion has an edge portion and a laminated portion, the edge portion is arranged along the edge adjacent to the light-transmitting portion with a specified width D1, which is formed by forming the phase control film on the transparent substrate, where 0.5≤D1, and the unit of the specified width D1 is μm, the laminated portion is arranged in a region other than the edge portion, and is formed by laminating the phase control film and the transmission control film on the transparent substrate, the laminated portion is formed by directly or indirectly laminating the transmission control film on the phase control film on the transparent substrate.

2. The photomask according to claim 1, wherein, The semi-transmissive portion has a portion adjacent to the light-shielding portion, and the phase difference φp between the semi-transmissive portion and the light-shielding portion for the light of the representative wavelength is 160≤φp≤200, and the unit of the phase difference φp is degrees.

3. The photomask according to claim 1 or 2, wherein, The phase control film and the transmission control film are made of materials having an etching selectivity to each other.

4. The photomask according to claim 1 or 2, wherein, the laminated portion further includes a region where a light-shielding film is laminated in addition to the phase control film and the transmission control film, the optical density OD of the light-shielding film is 3 or more.

5. The photomask according to claim 4, wherein, The laminated portion includes a region where the phase control film, the light-shielding film, and the transmission control film are laminated in sequence on the transparent substrate.

6. The photomask according to claim 5, wherein, the light-shielding portion further has a margin portion arranged between the laminated portion and the edge portion and formed with a specified width M, where 0<M≤0.8, and the unit of the specified width M is μm, the margin portion is a portion where the surface of the light-shielding film is exposed and a part of the film thickness is lost from the surface of the light-shielding film.

7. A method for manufacturing a photomask, which is a method for manufacturing a photomask having a transfer pattern including a light-transmitting portion, a light-shielding portion, and a semi-transmissive portion on a transparent substrate, the light-transmitting portion is formed by exposing the transparent substrate, the semi-transmissive portion is formed by forming a transmission control film on the transparent substrate, the light-shielding portion has an edge portion and a laminated portion, '' the edge portion is arranged along the edge adjacent to the light-transmitting portion with a specified width D1, which is formed by forming a phase control film on the transparent substrate, where 0.5≤D1, and the unit of the specified width D1 is μm, The lamination part is disposed in a region other than the edge part, and is formed by laminating the phase control film and the transmission control film on the transparent substrate. The manufacturing method includes the following steps: A step of preparing a photomask blank having the phase control film formed on the transparent substrate; A first patterning step of patterning the phase control film to form a phase control film pattern; and A second patterning step of forming a resist film on the transmission control film formed on the phase control film pattern and on the transparent substrate, performing drawing and development on the resist film, and patterning the transmission control film using the resist pattern thus formed. In the second patterning step, The resist pattern has an opening expanded by an amount D1 on each single side of the adjacent light-shielding part side with respect to the size of the region corresponding to the light-transmitting part. By patterning the transmission control film using the resist pattern as a mask, the edge part is formed.

8. The method for manufacturing a photomask according to claim 7, wherein The phase control film has a transmittance Tp and a phase shift amount φ4 for light of a representative wavelength included in the exposure light of the photomask, where Tp≥2, the unit of the transmittance Tp is %, 160≤φ4≤200, and the unit of the phase shift amount φ4 is degrees. The transmission control film has a transmittance Th and a phase shift amount φh for the light of the representative wavelength, where Th≥20, φh<90, the unit of the transmittance Th is %, and the unit of the phase shift amount φh is degrees.

9. The method for manufacturing a photomask according to claim 7 or 8, wherein, The phase control film and the transmission control film are made of materials having etching selectivity with respect to each other.

10. A method for manufacturing a photomask, which is a method for manufacturing a photomask having a transfer pattern including a light-transmitting part, a light-shielding part, and a semi-transmitting part on a transparent substrate. The light-transmitting part is formed by exposing the transparent substrate. The semi-transmitting part is formed by forming a transmission control film on the transparent substrate. The light-shielding part has an edge part, a lamination part, and a margin part. The edge part is disposed along the edge adjacent to the light-transmitting part with a predetermined width D1, and is formed by forming a phase control film on the transparent substrate, where 0.5≤D1, and the unit of the predetermined width D1 is μm. The lamination part is disposed in a region other than the edge part, and is formed by directly or indirectly laminating the transmission control film on the phase control film on the transparent substrate. The margin part is disposed between the edge part and the lamination part, and has a predetermined width M, where 0<M≤0.8, and the unit of the predetermined width M is μm. The manufacturing method includes the following steps: A step of preparing a photomask blank having the phase control film, a light-shielding film, and a first resist film formed in sequence on the transparent substrate; A step of performing drawing and development on the first resist film to form a first resist pattern; A first patterning step of using the first resist pattern to pattern the light-shielding film, and then patterning the phase control film to form a phase control film pattern; An undercutting step of using the first resist pattern to perform undercutting on the light-shielding film to form a light-shielding film pattern; And Second patterning process: A second resist film is formed on the transmission control film formed on the phase control film pattern, the light-shielding film pattern, and the transparent substrate, and the second resist film is drawn and developed. Using the formed second resist pattern, the transmission control film is patterned. In the second patterning process, The size of the second resist pattern has an opening expanded by an amount of D1 + M on each single side of the adjacent light-shielding portion side with respect to the region corresponding to the light-transmitting portion. By patterning the transmission control film using the second resist pattern as a mask, the edge portion and the margin portion are formed.

11. The method for manufacturing a photomask according to claim 10, wherein, The phase control film and the transmission control film are made of materials having an etching selectivity with respect to each other.

12. The method for manufacturing a photomask according to claim 10 or 11, wherein, The light-shielding film and the transmission control film are made of materials that can be etched using a common etchant for both.

13. The method for manufacturing a photomask according to claim 10 or 11, wherein The phase control film has a transmittance Tp and a phase shift amount φ4 with respect to the light of the representative wavelength included in the exposure light of the photomask, where Tp ≥ 2, the unit of the transmittance Tp is %, 160 ≤ φ4 ≤ 200, and the unit of the phase shift amount φ4 is degrees. The transmission control film has a transmittance Th and a phase shift amount φh with respect to the light of the representative wavelength, where Th ≥ 20, φh < 90, the unit of the transmittance Th is %, and the unit of the phase shift amount φh is degrees.

14. The method for manufacturing a photomask according to claim 10 or 11, wherein, The margin portion is a portion where the surface of the light-shielding film laminated on the transmission control film is exposed and a part of the film thickness is lost from the surface of the light-shielding film.

15. A method for manufacturing a display device, comprising the following steps: A step of preparing the photomask according to any one of claims 1 to 6, or the photomask obtained by the manufacturing method according to any one of claims 7 to 14; and A step of exposing the photomask using an exposure device.

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