Phase shift mask, method for manufacturing phase shift mask, and method for manufacturing display device

Abstract

The invention provides a phase shift mask, a manufacturing method of the phase shift mask and a manufacturing method of a display device. The phase shift mask is provided with a phase shift film on a translucent substrate, the phase shift film has formed thereon a transfer pattern including a correction hole portion, and the correction hole portion has a hole-shaped dig-in translucent portion formed by dig-in the surface of the translucent substrate, a correction film surrounding the outer periphery of the dig-in translucent portion, and a phase shift film surrounding the correction film. The phase difference [phi] P between the exposure light that has passed through the phase shift film and the exposure light that has passed through the air that has the same distance as the film thickness of the phase shift film is 150-210 degrees, and the phase difference [phi] M between the exposure light that has passed through the correction film and the exposure light that has passed through the air that has the same distance as the film thickness of the correction film is less than the phase difference [phi] P. The phase difference [phi] H between the exposure light that has passed through the correction film and the exposure light that has passed through the dig-in light-transmitting portion is 150-210 degrees, and the difference between the transmittance TM of the correction film to the exposure light and the transmittance TP of the phase shift film to the exposure light is 2% or less.

Description

Technical Field

[0001] The present invention relates to a phase-shift mask, a method for manufacturing the phase-shift mask, and a method for manufacturing a display device. Background Art

[0002] In recent years, in display devices such as FPD (Flat Panel Display) represented by OLED (Organic Light Emitting Diode), large screen, wide viewing angle, folding and other flexibility as well as high-precision and high-speed display have developed rapidly. One of the elements required for this high-precision and high-speed display is to produce electronic circuit patterns such as components and wiring that are fine and have high dimensional accuracy. The patterning of electronic circuits for the display device mostly uses photolithography. Therefore, a phase-shift mask for the manufacture of display devices with fine and high-precision patterns is required. In the phase-shift mask, the portion corresponding to the light-shielding portion of the binary mask is formed by a halftone film with low transmittance and a 180-degree phase shift.

[0003] For example, Patent Document 1 describes a method for manufacturing a phase-shift mask, which includes a transfer pattern on a transparent substrate 1 that includes a semi-transparent portion formed by patterning a semi-transparent film 2, wherein the semi-transparent portion 12 has a specified transmittance and a phase difference of approximately 180 degrees with respect to a representative wavelength of exposure light, and the method for manufacturing the phase-shift mask includes a correction film forming step of forming a correction film 4 in a specified area of ​​the semi-transparent portion that includes defects, wherein the correction film is a laminated film including a correction film A4a formed by a laser CVD method and a correction film B4b formed by a focused ion beam method.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-20120

[0007] For example, with respect to the thin film transistor (TFT) used in the above-mentioned display device, if the contact hole formed in the interlayer insulating film among the multiple patterns constituting the TFT does not have the function of reliably connecting the patterns of the upper layer and the lower layer, the correct operation cannot be guaranteed. On the other hand, in order to maximize the aperture ratio of the display device and form a bright and power-saving display device, the diameter of the contact hole is required to be sufficiently small. Along with this, it is expected that the diameter of the hole pattern possessed by the photomask used to form such contact holes is also miniaturized (for example, less than 3μm). For example, it is believed that a hole pattern with a diameter of less than 2.5μm, and further a diameter of less than 2.0μm, is required, and in the near future, it is also expected to form a pattern with a diameter less than 1.5μm. Against such a background, a manufacturing technology for a display device that can reliably transfer tiny contact holes is required.

[0008] For example, when a defect occurs in a pattern portion formed of a phase shift film included in a halftone phase shift mask, it is not always easy to correct the defect.

[0009] Generally, it is known that when a defect is generated in a phase shift mask and it is desired to correct the defect by using a correction film, a FIB (focused ion beam) device is used as a correction unit.

[0010] However, it is known that in the method of simply depositing a correction film on the defective portion of the phase shift mask using a FIB apparatus, it is sometimes impossible to restore the same function as the phase shift mask without defects. It is known that even if a correction film is deposited on the defective portion of the phase shift mask using a FIB apparatus, it is not easy to form a correction film that has a phase shift amount of approximately 180 degrees with respect to exposure light and has a desired transmittance set for the phase shift film of the normal portion.

[0011] On the other hand, there is also a method of using a laser CVD method to correct defects in a phase shift mask forming a semi-transparent portion. However, when using the laser CVD method, a process of removing the deposited correction film by wet etching is inevitably generated, and it is difficult to correct defects in a micro hole pattern with the desired accuracy. Summary of the invention

[0012] Problems to be solved by the invention

[0013] The present invention is made to solve the above-mentioned problems. That is, the purpose of the present invention is to obtain an excellent phase shift mask and a method for manufacturing the same, and a method for manufacturing a display device, which are advantageously suitable for the exposure environment of a mask for manufacturing a display device and can stably transfer a fine hole pattern.

[0014] Means for solving problems

[0015] The present invention has the following configuration as a means for solving the above-mentioned problems.

[0016] (Structure 1) A phase shift mask comprising a phase shift film on a light-transmitting substrate, wherein the phase shift film is formed with a transfer pattern including a correction hole portion, characterized in that:

[0017] The correction hole portion includes: a hole-shaped hollowed-out light-transmitting portion formed by hollowing out the surface of the light-transmitting substrate; a correction film formed to surround the outer periphery of the hollowed-out light-transmitting portion; and a phase shift film formed to surround the correction film.

[0018] The phase difference Φ generated between the exposure light after passing through the phase shift film and the exposure light after passing through the air at a distance equal to the film thickness of the phase shift film is P is 150 degrees or more and 210 degrees or less,

[0019] The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the air at a distance equal to the film thickness of the correction film is M is smaller than the phase difference Φ P ,

[0020] The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the hollowed-in light-transmitting portion H is 150 degrees or more and 210 degrees or less,

[0021] The transmittance T of the correction film to the exposure light M The transmittance T of the phase shift film to the exposure light P The difference is less than 2%.

[0022] (Structure 2) A phase shift mask according to Structure 1, characterized in that the transmittance T of the phase shift film is P The exposure light contains at least light having a wavelength of 365 nm.

[0023] (Structure 3) A phase shift mask according to Structure 1, characterized in that the transmittance T of the correction film M More than 10%.

[0024] (Structure 4) According to the phase shift mask of Structure 1, it is characterized in that the phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the air at a distance equal to the film thickness of the correction film is M Below 100 degrees.

[0025] (Structure 5) The phase-shift mask according to Structure 1, characterized in that the exposure light contains at least light with a wavelength of 365 nm.

[0026] (Structure 6) A method for manufacturing a phase shift mask, wherein the phase shift mask comprises a phase shift film having a transfer pattern formed on a light-transmitting substrate, wherein the manufacturing method comprises the following steps:

[0027] forming a transfer pattern on the phase shift film disposed on the light-transmitting substrate, the transfer pattern including a hole portion consisting of a light-transmitting portion in a hole shape;

[0028] performing defect inspection on the transfer pattern of the phase shift film to identify a hole portion having a defect; and

[0029] Correct the defects,

[0030] The step of correcting the defect includes: forming a correction film on the hole portion having the defect so as to surround the outer periphery of the light-transmitting portion; and digging the surface of the light-transmitting substrate of the light-transmitting portion to form a dug light-transmitting portion.

[0031] The phase difference Φ generated between the exposure light after passing through the phase shift film and the exposure light after passing through the air at a distance equal to the film thickness of the phase shift film is P is 150 degrees or more and 210 degrees or less,

[0032] The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the air at a distance equal to the film thickness of the correction film is M is smaller than the phase difference Φ P ,

[0033] The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the hollowed-in light-transmitting portion H is 150 degrees or more and 210 degrees or less,

[0034] The transmittance T of the correction film to the exposure light M The transmittance T of the phase shift film to the exposure light P The difference is less than 2%.

[0035] (Structure 7) The method for manufacturing a phase shift mask according to Structure 6 is characterized in that the transmittance T of the phase shift film is P More than 10%.

[0036] (Structure 8) The method for manufacturing a phase shift mask according to Structure 6 is characterized in that the transmittance T of the correction film M More than 10%.

[0037] (Structure 9) The method for manufacturing a phase shift mask according to Structure 6, wherein the exposure light contains at least light having a wavelength of 365 nm.

[0038] (Structure 10) A method for manufacturing a display device, characterized by comprising the following steps:

[0039] placing the phase shift mask of any one of structures 1 to 5 on a mask stage of an exposure device; and

[0040] The phase shift mask is irradiated with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device.

[0041] (Structure 11) A method for manufacturing a display device, characterized by comprising the following steps:

[0042] placing the phase shift mask manufactured by the method for manufacturing a phase shift mask according to any one of Structures 6 to 9 on a mask stage of an exposure device; and

[0043] The phase shift mask is irradiated with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device.

[0044] Effects of the Invention

[0045] According to the present invention, it is possible to provide an excellent phase shift mask and a method for manufacturing the same, and a method for manufacturing a display device, which are advantageously suitable for an exposure environment of a mask for manufacturing a display device and can stably transfer a fine hole pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 (a) is a schematic top view and (b) is a schematic cross-sectional view of an example of a phase shift mask in the first embodiment of the present invention.

[0047] Figure 2 (a) is a schematic top view and (b) is a schematic cross-sectional view of another example of the phase shift mask in the second embodiment of the present invention.

[0048] Figure 3 It is a diagram showing an aerial image of light intensity formed on a transfer target body when the phase shift mask according to Example 1 of the present invention is used.

[0049] Figure 4 It is a diagram showing an aerial image of light intensity formed on a transfer target body when the phase shift mask according to Example 2 of the present invention is used.

[0050] Figure 5 It is a diagram showing an aerial image of light intensity formed on a transfer target body when a phase shift mask according to a comparative example of the present invention is used.

[0051] Figure 6 This is a graph showing the relationship between the phase difference and the transmittance under light having a wavelength of 334 nm in a correction film formed by the repair device (FIB device) used in the present invention.

[0052] Description of Reference Numerals

[0053] 1Transparent substrate

[0054] 1A light-transmitting part

[0055] 1B dig into the light-transmitting part

[0056] 2 Phase Shift Film

[0057] 3A hole

[0058] 3B correction hole

[0059] 4Correction film

[0060] 5 shading film

[0061] 100, 110 phase shift mask DETAILED DESCRIPTION

[0062] First, the process leading to the present invention will be described. The present inventors have conducted intensive studies on the structure of an excellent phase shift mask that is advantageously suitable for the exposure environment of a mask for manufacturing a display device and that can stably transfer a fine hole pattern.

[0063] The FIB device mainly uses gallium ions to deposit carbon-based films. The inventors investigated the relationship between phase difference and transmittance of the correction film formed using the existing FIB device. The results are shown in Figure 6 . Figure 6 : is a graph showing the relationship between the phase difference and the transmittance under the light with a wavelength of 334nm in the correction film formed by the repair device (FIB device) used in the embodiment of the present invention. Figure 6 As shown in FIG. 1 , the phase difference and the transmittance are inversely proportional. In this correction film, it is difficult to achieve both the desired phase difference (e.g., 180 degrees) and the desired transmittance (e.g., 10%). In addition, the graph of the relationship between the phase difference and the transmittance of the correction film has approximately the same tendency in the case of i-line (wavelength of 365nm) light. In addition, the graph of the relationship between the phase difference and the transmittance of the correction film has the same inversely proportional tendency in the case of h-line (wavelength of 405nm) light. Even when the correction based on this correction film is performed on the pattern of the phase shift film with a higher transmittance of the exposure light of the h-line, it is difficult to achieve both the desired phase difference and the desired transmittance.

[0064] Therefore, the inventors changed their concept and studied whether a fine hole pattern could be stably transferred by forming a correction film formed by an existing FIB device in such a way that only one of the phase difference and the transmittance was within a desired range. As a result, it was found that by forming a correction film in such a way that the transmittance was within a desired range and forming a correction hole portion by digging the surface (translucent portion) of a light-transmitting substrate surrounded by the correction film to ensure a desired phase difference, performance comparable to that of a hole portion formed in a phase shift film could be obtained, and a fine hole pattern could be stably transferred.

[0065] The phase-shift mask of the present invention is derived through the above-mentioned in-depth studies.

[0066] <Phase Shift Mask of First Embodiment>

[0067] Figure 1 An example of the phase shift mask in the first embodiment of the present invention is described. Figure 1 (a) is a schematic top view, Figure 1 (b) is a schematic cross-sectional view.

[0068] like Figure 1 As shown, the phase shift mask 100 includes a light-transmitting substrate 1 and a phase shift film 2 (hereinafter, sometimes simply referred to as “phase shift film 2 ”) having a transfer pattern (phase shift pattern) including correction holes formed on the light-transmitting substrate 1 .

[0069] The correction hole portion 3B includes: a hollowed-out light-transmitting portion 1B having a hole shape formed by hollowing out the surface of the light-transmitting substrate 1, a correction film 4 formed to surround the outer periphery of the hollowed-out light-transmitting portion 1B, and a phase shift film 2 formed to surround the correction film 4. Figure 1 As shown, the transfer pattern (phase shift pattern) in this embodiment includes a hole portion 3A (hereinafter, the hole portion 3A not dug is sometimes referred to as "hole portion 3A") formed by a light-transmitting portion 1A (hereinafter, sometimes referred to as "light-transmitting portion 1A") in a hole shape not dug out formed in the phase shift film 2.

[0070] The size of the light-transmitting portion 1A of the hole 3A is preferably 4.0 μm or less, more preferably 3.0 μm or less, and further preferably 2.5 μm or less. On the other hand, the size of the light-transmitting portion 1A of the hole 3A is preferably 0.8 μm or more. In addition, the size of the hollowed-in light-transmitting portion 1B of the correction hole 3B is preferably 4.0 μm or less, more preferably 3.0 μm or less, and further preferably 2.5 μm or less, similarly to the hole 3A. On the other hand, the size of the hollowed-in light-transmitting portion 1B of the correction hole 3B is preferably 0.8 μm or more.

[0071] In addition, Figure 1In the figure, the shape of these hole portions 3A and 3B is shown as being approximately square when viewed from above, but it is not limited to this. The shape of the hole portions 3A and 3B may also be other shapes such as rectangles, polygons, circles, and ellipses. In the case where the shape of the hole portions 3A and 3B is approximately square, the size refers to the length of one side. In the case where the shape of the hole portions is a rectangle, the size refers to the length of the long side. In the case where the shape of the hole portions 3A and 3B is a polygon, the size refers to the diameter of the circle inscribed in the polygon. In the case where the shape of the hole portions 3A and 3B is a circle, the size refers to the diameter. In the case where the shape of the hole portions 3A and 3B is an ellipse, the size refers to the length of the major axis (major diameter).

[0072] The light-transmitting substrate 1 is transparent to the exposure light. When there is no surface reflection loss, the light-transmitting substrate 1 has a transmittance of 85% or more, preferably a transmittance of 90% or more to the exposure light. The light-transmitting substrate 1 is made of a material containing silicon and oxygen, and can be made of a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda-lime glass, and low thermal expansion glass (SiO2-TiO2 glass, etc.).

[0073] The phase shift film 2 may be made of a material containing a transition metal and silicon (Si). As the transition metal, molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr), etc. are preferred, and titanium and molybdenum are more preferred. In addition, the phase shift film may use a material containing chromium (Cr), for example, a chromium-based material containing Cr and at least one of oxygen (O) and nitrogen (N). Specifically, CrO, CrN, CrON, etc. may be exemplified. The phase shift film 2 is preferably capable of wet etching.

[0074] As exposure light, for example, light having a wavelength range of 300 nm to 500 nm can be used. As a light source of an exposure device for display device manufacturing, for example, a light source (for example, a high-pressure mercury lamp) containing any one or more of i-line, h-line, and g-line can be appropriately used. The representative wavelength of the exposure light can be set to any wavelength included in the above wavelength range.

[0075] In addition, when the pattern is miniaturized and it is desired to shift the center of gravity of the wavelength range of the exposure light to the short wavelength side, light having a wavelength range (e.g., 250nm to 400nm) on the shorter wavelength side than the above wavelength range can be used as the exposure light. For example, light having a wavelength range on the shorter wavelength side including two or more of 313nm, 334nm, and 365nm can be used as the exposure light. Furthermore, light having a single wavelength of i-line (365nm) can also be used as the exposure light.

[0076] Thus, the exposure light preferably includes at least light having a wavelength of 365 nm.

[0077] In this specification, unless otherwise specified, the i line (365 nm) is used as an example of a representative wavelength.

[0078] The phase shift film 2 has a phase shift effect on the representative wavelength of the exposure light. That is, a phase difference Φ is generated between the exposure light after passing through the phase shift film 2 and the exposure light after passing through the air at the same distance as the film thickness of the phase shift film 2. P . Phase difference Φ P Preferably, it is approximately 180 degrees. In this specification, approximately 180 degrees means 150 degrees or more and 210 degrees or less, preferably 160 degrees or more and 200 degrees or less, and more preferably 170 degrees or more and 190 degrees or less. In addition, the phase shift film 2 preferably has a phase difference of approximately 180 degrees for all main wavelengths (e.g., i-line, h-line, g-line) included in the exposure light.

[0079] The transmittance of the phase shift film 2 to the exposure light satisfies the value required for the phase shift film 2. The transmittance T of the phase shift film 2 to the light of the representative wavelength included in the exposure light is P On the other hand, the transmittance T of the phase shift film 2 to the light of the representative wavelength included in the exposure light is preferably 10% or more. P It is preferably 50% or less, and more preferably 40% or less.

[0080] To ensure optical performance, the film thickness of the phase shift film 2 is preferably 200 nm or less, more preferably 180 nm or less, and further preferably 150 nm or less. To ensure desired transmittance, the film thickness of the phase shift film 2 is preferably 50 nm or more, and more preferably 60 nm or more.

[0081] The phase shift film 2 can be formed by a known film forming method such as sputtering. Alternatively, the transfer pattern can be formed by a known method such as wet etching.

[0082] The correction film 4 is formed in a region including a white defect where the phase shift film 2 is lacking.

[0083] The correction film 4 is a metal film or a carbon-containing film that does not substantially contain oxygen. It should be noted that, in this specification, “does not substantially contain oxygen” means that the content of O is less than 5%.

[0084] When the correction film 4 is a carbon-containing film, the C content is preferably 90% to 100%. This can improve chemical resistance. In addition, the correction film 4 may contain elements other than C (for example, Ga, Si, W, Pt, Au, etc.).

[0085] When the correction film is a metal film, for example, it can be a film containing Mo or Cr.

[0086] The correction film 4 has a transmittance T of the representative wavelength of the exposure light. M The transmittance T of the correction film 4 to the exposure lightM The transmittance T of the phase shift film 2 to the exposure light P The difference is preferably 2% or less (within the range of ±2%), and more preferably 1% or less (within the range of ±1%). M It is preferably 10% or more.

[0087] The phase difference Φ generated between the exposure light after passing through the correction film 4 and the exposure light after passing through the air at the same distance as the film thickness of the correction film 4 is M Smaller than the phase difference Φ P . Phase difference Φ M It can be less than 100 degrees. Phase difference Φ M Can be greater than 0 degrees.

[0088] The width of the correction film 4 may be any width that ensures a range in which white defects can be corrected, and is preferably 0.4 μm or more. The width of the correction film 4 is preferably 10 μm or less.

[0089] In order to achieve the above optical characteristics, the film thickness of the correction film 4 is preferably 90 nm or less, more preferably 80 nm or less. On the other hand, the film thickness of the correction film 4 is preferably 30 nm or more, more preferably 50 nm or more.

[0090] The correction film 4 can be formed using a FIB device.

[0091] The correction hole portion 3B is a hole-shaped hollowed-out light-transmitting portion 1B formed by hollowing out the surface of the light-transmitting substrate 1 .

[0092] A phase difference of approximately 180 degrees (150 degrees or more and 210 degrees or less) is generated between the exposure light after passing through the correction film 4 and the exposure light after passing through the hollowed-out light-transmitting portion 1B. H . Phase difference Φ H It is preferably 160 degrees or more and 200 degrees or less, and more preferably 170 degrees or more and 190 degrees or less.

[0093] In addition, the phase difference Φ generated between the exposure light after passing through the hollowed-out light-transmitting portion 1B and the exposure light after passing through the light-transmitting portion 1A is D It is preferably 50 degrees or more and 140 degrees or less, more preferably 65 degrees or more and 125 degrees or less, and further preferably 80 degrees or more and 110 degrees or less.

[0094] The correction hole 3B is preferably dug into the light-transmitting portion 1B to a depth that exhibits the above-mentioned phase difference Φ H , Φ D Depth.

[0095] It is preferable that the dimension (width dimension) of the correction hole 3B hollowed into the light-transmitting portion 1B is the same as that of the light-transmitting portion 1A of the hole 3A.

[0096] For example, the hollowed light-transmitting portion 1B can be formed using a FIB apparatus.

[0097] By configuring the correction hole portion 3B in this manner, it is possible to ensure a phase difference and transmittance comparable to those of the light-transmitting portion 1A, and to exhibit a good phase shift function.

[0098] The phase shift mask 100 according to the first embodiment of the present invention has the above-described structure, and can be an excellent phase shift mask 100 that is advantageously suitable for the exposure environment of a mask for manufacturing a display device and can stably transfer a fine hole pattern.

[0099] In the present embodiment, the transfer pattern including the hole portions 3A and the correction hole portions 3B is described, but the present invention is not necessarily limited thereto. For example, the hole pattern of the transfer pattern may be entirely composed of the correction hole portions 3B.

[0100] In addition, Figure 1 , the shapes of these holes are shown to be approximately square when viewed from above, but the shape is not limited to this and may be other shapes such as polygonal, circular, elliptical, etc. (the same applies to subsequent embodiments).

[0101] <Phase Shift Mask of Second Embodiment>

[0102] Figure 2 Another example of the phase shift mask in the second embodiment of the present invention is described. Figure 2 (a) is a schematic top view, Figure 2 (b) is a schematic cross-sectional view. The light-transmitting substrate 1, the phase shift film 2, the correction film 4, the hole 3A, and the correction hole 3B in the phase shift mask 110 of the second embodiment are the same as those in the first embodiment, and thus their description is omitted.

[0103] The phase shift mask 110 of the second embodiment has a light shielding film 5 having a light shielding pattern on the phase shift film 2. The light shielding film 5 has a light shielding pattern ( Figure 2 2 shows an example in which a light shielding pattern is formed outside the pattern of the phase shift film 2 constituting the hole portion 3A and outside the correction film 4 constituting the correction hole portion 3B).

[0104] The light shielding film 5 is disposed on the upper side of the phase shift film 2 , and is made of a material having etching resistance to an etching solution for etching the phase shift film 2 (having an etching selectivity different from that of the phase shift film 2 ).

[0105] The light-shielding film 5 is preferably made of a chromium-based material containing chromium (Cr). The light-shielding film 5 is more preferably made of a material containing chromium and substantially free of silicon. Substantially free of silicon means that the silicon content is less than 2%. As the chromium-based material, more specifically, chromium (Cr), or a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C) can be cited. In addition, as the chromium-based material, a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C) and also containing fluorine (F) can be cited. For example, as the material constituting the light-shielding film 5, Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF can be cited.

[0106] The light shielding film 5 can be formed by a known film forming method such as a sputtering method.

[0107] The light shielding film 5 has a function of shielding the transmission of the exposure light, and the optical density of the exposure light in the portion where the phase shift film 2 and the light shielding film 5 are stacked is preferably 3 or more, more preferably 3.5 or more, and further preferably 4 or more. It should be noted that in this embodiment, the light shielding film 5 is provided on the phase shift film 2, but it may also be an etching mask film having an etching selectivity different from that of the phase shift film 2. In this case, a low-transmittance film having a lower transmittance than the phase shift film is preferably used.

[0108] It should be noted that Figure 2 The phase shift mask of the second embodiment shown has a structure in which a phase shift film 2 and a light shielding film 5 are sequentially stacked on a light-transmitting substrate 1, but it may also be a structure in which a light shielding film 5 and a phase shift film 2 are sequentially stacked. In this case, the light shielding film 5 having a light shielding pattern may be first formed on the light-transmitting substrate 1, and then the phase shift film 2 may be stacked and the phase shift pattern may be formed, so there may be no etching selectivity between the phase shift film 2 and the light shielding film 5.

[0109] The phase shift mask 110 according to the second embodiment of the present invention has the above-described structure, and can be an excellent phase shift mask that is advantageously suitable for the exposure environment of a mask for manufacturing a display device and can stably transfer a fine hole pattern.

[0110] Next, a method for manufacturing a phase shift mask of the present invention will be described.

[0111] In the manufacturing method of the phase shift mask of the present invention, the phase shift mask has a phase shift film with a transfer pattern formed on a translucent substrate, and the manufacturing method has the following steps: forming a transfer pattern on the phase shift film arranged on the translucent substrate, the transfer pattern including a hole portion consisting of a light-transmitting portion in a hole shape; performing defect inspection on the transfer pattern of the phase shift film to determine the hole portion with defects; and correcting the defects, the defect correction step including: forming a correction film on the hole portion with defects in a manner of surrounding the outer periphery of the light-transmitting portion; and digging into the surface of the light-transmitting substrate of the light-transmitting portion to form a dug-in light-transmitting portion.

[0112] <Method for Manufacturing Phase Shift Mask According to First Embodiment>

[0113] When manufacturing the phase shift mask 100 of the first embodiment, a mask blank having a phase shift film formed on a light-transmitting substrate is prepared. The specific structures of the light-transmitting substrate and the phase shift film formed on the mask blank are the same as the light-transmitting substrate 1 and the phase shift film 2 formed on the phase shift mask 100 of the first embodiment, except that no transfer pattern is formed.

[0114] Then, a transfer pattern including hole portions 3A constituted by a hole-shaped light-transmitting portion is formed on the phase shift film 2. For example, a resist film is formed on the phase shift film, and the phase shift film is wet-etched using the resist film pattern including the hole portions formed by the resist film as a mask, thereby forming a transfer pattern including the hole portions 3A on the phase shift film 2.

[0115] The transfer pattern of the phase shift film 2 is inspected for defects, and the defective hole portion 3A is identified.

[0116] A step of correcting the defect is performed on the defective hole portion 3A.

[0117] The defect repairing step includes forming a repair film 4 to surround the outer periphery of the light-transmitting portion 1A with respect to the defective hole 3A and forming a hollow light-transmitting portion 1B by hollowing the surface of the light-transmitting substrate 1 of the light-transmitting portion 1A.

[0118] The correction film 4 can be formed using an FIB apparatus. A known apparatus can be used as the FIB apparatus for forming the correction film 4. As an ion source, for example, Ga (gallium) can be used.

[0119] As a raw material gas for forming the correction film 4 by the FIB method, for example, a raw material gas containing pyrene (C 16 H 10 ), Philippines (C 14 H 10), or a gas of a hydrocarbon compound such as styrene (C8H8), a gas containing W such as W(CO)6, WF6, or WCl6, a mixed gas of tetramethyl orthosilicate (Si(OCH3)4:Tetramethoxysilane) and oxygen called TMOS, dimethyl gold hexafluoroacetylacetonate (C7H7F6O2Au:Dimethyl gold hexafluoro acetylacetonate) called DMG(hfac), (trimethyl)methylcyclopentadientyltrimethyl platinum (IV) called (MeCp)PtMe3 gas, and copper (+1)hexafluoro acethylacetonate trimethylvinylsilane called Cu(hfac)TMVS. In this embodiment, the case where pyrene is used as a raw material gas is described.

[0120] Examples of the raw material gas for a film containing Mo include MoF6, Mo(CO)6, and MoCl5. Examples of the raw material gas for a film containing Cr include Cr(C6H6)2.

[0121] Using a FIB apparatus, the correction film 4 is formed to a predetermined thickness so as to have a transmittance T of the representative wavelength of the exposure light. M , the transmittance T M The transmittance T of the phase shift film 2 to the exposure light P The difference is less than 2%. At this time, the phase difference Φ of the correction film 4 to the exposure light M Smaller than the phase difference Φ of the exposure light of the phase shift film 2 P (Refer to Figure 6 ).

[0122] The hollow light-transmitting portion 1B can be formed using a FIB apparatus. As an ion source, for example, Ga (gallium) can be used.

[0123] The source gas for forming the hollow light-transmitting portion 1B by the FIB method is not particularly limited as long as it has a property capable of etching the light-transmitting substrate 1. For example, a fluorine-based etching gas can be used.

[0124] The FIB device is used to form a hollow transparent portion 1B having a predetermined depth and a predetermined width so that the phase difference φ generated between the exposure light after passing through the correction film 4 and the exposure light after passing through the hollow transparent portion 1B is H It is 150 degrees or more and 210 degrees or less.

[0125] The step of forming the correction film 4 and the step of forming the hollowed-in light-transmitting portion 1B may be performed either first or in parallel.

[0126] In this way, the phase shift mask 100 according to the first embodiment including the phase shift film 2 on which the transfer pattern including the correction hole portion 3B is formed can be manufactured.

[0127] <Method for Manufacturing Phase Shift Mask According to Second Embodiment>

[0128] When manufacturing the phase shift mask of the second embodiment, a mask blank having a phase shift film and a light shielding film formed on a light-transmitting substrate is prepared. The specific structures of the light-transmitting substrate, the phase shift film, and the light shielding film formed on the mask blank are the same as the light-transmitting substrate 1, the phase shift film 2, and the light shielding film 5 formed on the phase shift mask 110 of the second embodiment, except that the transfer pattern and the light shielding pattern are not formed.

[0129] Then, a light shielding pattern is formed on the light shielding film 5, and a transfer pattern including a hole portion consisting of a light-transmitting portion in a hole shape is formed on the phase shift film 2. For example, a resist film is formed on the light shielding film 5, and the light shielding film 5 is wet-etched using the resist film pattern including the hole portion 3A formed by the resist film as a mask, thereby forming a transfer pattern including the hole portion 3A on the light shielding film 5. Then, wet etching is performed using the light shielding film 5 on which the transfer pattern is formed as a mask, and the transfer pattern is formed on the phase shift film 2. Thereafter, a second resist film is formed on the light shielding film 5, and the light shielding film 5 is wet-etched using the resist film pattern including a light shielding band formed by the second resist film as a mask, thereby forming a light shielding pattern on the light shielding film 5.

[0130] The transfer pattern of the phase shift film 2 is inspected for defects, and the defective hole portion 3A is identified.

[0131] For the hole portion 3A having a defect, a step of correcting the defect and forming the corrected hole portion 3B is performed as follows.

[0132] As in the case of manufacturing the phase shift mask 100 of the first embodiment, the correction film 4 is formed with a predetermined film thickness using a FIB apparatus so that the correction film 4 has a transmittance T 0 to the exposure light. M , the transmittance T M The transmittance T of the phase shift film 2 to the exposure light P The difference is less than 2%. At this time, the phase difference Φ of the correction film 4 to the exposure light M Smaller than the phase difference Φ of the exposure light of the phase shift film 2 P (Refer to Figure 6 ).

[0133] Then, similarly to the case of manufacturing the phase shift mask 100 of the first embodiment, a hollowed-in light-transmitting portion 1B having a predetermined depth and a predetermined width is formed using an FIB apparatus so that a phase difference φ generated between the exposure light after passing through the correction film 4 and the exposure light after passing through the hollowed-in light-transmitting portion 1B is H It is 150 degrees or more and 210 degrees or less.

[0134] In this way, the phase shift mask 110 according to the second embodiment including the phase shift film 2 on which the transfer pattern including the correction hole portion 3B is formed can be manufactured.

[0135] <Method for manufacturing display device>

[0136] The manufacturing method of the display device of the present embodiment is described. The manufacturing method of the display device of the present embodiment comprises: a step of placing the phase shift mask described in any one of the above embodiments, or a phase shift mask manufactured by the manufacturing method of the phase shift mask described in any one of the above embodiments, on a mask stage of an exposure device; and a step of irradiating the phase shift mask with exposure light to transfer a transfer pattern to a resist film provided on a substrate for the display device.

[0137] Hereinafter, each step will be described in detail.

[0138] In the placement step, the phase shift mask of the above embodiment is placed on a mask stage of an exposure device. Here, the phase shift mask is arranged to face a resist film formed on a substrate for a display device via a projection optical system of the exposure device.

[0139] In the pattern transfer process, the phase shift mask is irradiated with exposure light, and the transfer pattern including the thin film pattern for pattern formation is transferred to the resist film formed on the substrate for the display device. The exposure light is a composite light including a plurality of wavelengths selected from the wavelength region of 313nm to 436nm, or a monochromatic light selected by intercepting from the wavelength region of 313nm to 436nm by a filter, etc., or a monochromatic light emitted from a light source having a wavelength region of 313nm to 436nm. For example, the exposure light is a composite light including at least one of the i-line, the h-line and the g-line, or a monochromatic light of the i-line. By using the composite light as the exposure light, the intensity of the exposure light can be increased and the productivity can be increased. Therefore, the manufacturing cost of the display device can be reduced.

[0140] According to the method for manufacturing a display device of this embodiment, a high-definition display device having high resolution and fine contact holes can be manufactured.

[0141] [Example]

[0142] Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

[0143] The transfer performance of the phase shift mask of this embodiment was compared and evaluated by optical simulation. Specifically, the transfer performance of the phase shift mask having a transfer pattern for forming a hole pattern with a diameter of 1.5 μm on a transfer target was compared and evaluated by optical simulation when the exposure conditions were set in common.

[0144] (Example 1)

[0145] like Figure 1 As shown, the phase shift mask of Example 1 includes a phase shift film 2 having a transfer pattern formed on a light-transmitting substrate 1. The phase shift film 2 has a transmittance T of 16% for exposure light having a typical wavelength of 334 nm. P and a phase difference of 180 degrees Φ P The transfer pattern includes a hole portion 3A composed of a hole-shaped light-transmitting portion 1A and a correction hole portion 3B having a hollowed-out light-transmitting portion 1B. The size (one side of the square) of the light-transmitting portion 1A of the hole portion 3A and the hollowed-out light-transmitting portion 1B of the correction hole portion 3B is 2.4 μm. The correction film 4 has a transmittance T of 16% for exposure light representing a wavelength of 334 nm. M and a phase difference of 85 degrees Φ M There is a 180-degree phase difference Φ between the exposure light after passing through the correction film 4 and the exposure light after passing through the hollowed-out light-transmitting portion 1B. H (That is, there is a 95 degree phase difference Φ between the exposure light after passing through the hollowed-out light-transmitting portion 1B and the exposure light after passing through the light-transmitting portion 1A. D ). The film thickness of the correction film 4 is set to 70 nm, and the depth of the digging into the light-transmitting portion 1B is set to 240 nm. In addition, optical simulations were performed for the correction film 4 formed in the correction hole portion 3B with a size (width) of 1 μm, 2 μm, 3 μm, and 5 μm and the hole portion 3A.

[0146] Figure 3 FIG. 1 is a diagram showing an aerial image of light intensity formed on a transfer target when the phase shift mask 100 according to Example 1 of the present invention is used. Figure 3 , the results of optical simulations of the hole portion 3A and the correction hole portion 3B of the phase shift film 2 in Example 1 are shown.

[0147] For example, in order to transfer a fine light-transmitting pattern with a small diameter, the spatial image formed on the transfer object by the exposure light after passing through the photomask, that is, the profile of the transmitted light intensity curve must be good. Specifically, it is important that the peak of the transmitted light intensity has a sharp inclination, a nearly vertical rise, and a high absolute value of the peak light intensity (when a secondary peak is formed around it, the intensity is relatively high enough relative to the secondary peak).

[0148] like Figure 3As shown, in the correction hole portion 3B formed by the correction film 4 of any size in Example 1, the absolute value of the peak light intensity or the inclination of the peak formation is consistent with the profile of the hole portion 3A ( Figure 3 "Ref") is equal to or greater than that of the hole portion 3A and has a preferred profile that is equal to or greater than that of the hole portion 3A.

[0149] When evaluating the phase shift mask more quantitatively based on the optical performance, the following indexes can be used.

[0150] (1) Depth of Focus (DOF)

[0151] Indicates the depth of focus within the range of ±10% relative to the target CD (Critical Dimension). If the DOF value is high, it is less likely to be affected by the flatness of the transfer body (such as the panel substrate for the display device), and a fine pattern can be reliably formed, and its CD (line width) deviation can be suppressed.

[0152] (2) MEEF (Mask Error Enhancement Factor)

[0153] It is a numerical value indicating the ratio of the CD error of the mask to the CD error of the pattern formed on the transfer body. The lower the MEEF is, the more the CD error of the pattern formed on the transfer body can be reduced.

[0154] (3) Exposure margin (EL)

[0155] It indicates the ratio of the exposure margin that satisfies the CD deviation of the target panel CD of 1.5 μm±10%.

[0156] The results of evaluation of the phase shift mask of Example 1 with respect to these items are shown in Table 1 (Table 1 shows the cases where the size (width) of the correction film 4 is 1 μm, 2 μm, and 5 μm).

[0157] [Table 1]

[0158]

[0159] As shown in Table 1, the correction hole 3B having the hollowed-out light-transmitting portion in Example 1 obtained a good or comparable value for DOF compared with the hole 3A. A better value for MEEF was obtained than the hole 3A. A value comparable to that of the hole 3A was also obtained for EL.

[0160] From this result, it can be said that even if the phase shift mask of Example 1 is placed on the mask stage of an exposure device and the resist film transferred to the display device is exposed, the hole pattern finally formed on the display device can be formed with high accuracy.

[0161] (Example 2)

[0162] like Figure 1 As shown, the phase shift mask of Example 2 includes a phase shift film 2 having a transfer pattern formed on a light-transmitting substrate 1. The phase shift film 2 has a transmittance T of 10% for exposure light having a typical wavelength of 334 nm. P and a phase difference of 180 degrees Φ P The transfer pattern includes a hole portion 3A composed of a hole-shaped light-transmitting portion 1A and a correction hole portion 3B having a hollowed-out light-transmitting portion 1B. The size (one side of the square) of the light-transmitting portion 1A of the hole portion 3A and the hollowed-out light-transmitting portion 1B of the correction hole portion 3B is 2.4 μm. The correction film 4 has a transmittance T of 10% for exposure light representing a wavelength of 334 nm. M and a phase difference of 105 degrees Φ M There is a 180-degree phase difference Φ between the exposure light after passing through the correction film 4 and the exposure light after passing through the hollowed-out light-transmitting portion 1B. H (That is, there is a phase difference of 75 degrees between the exposure light after passing through the hollowed-out light-transmitting portion 1B and the exposure light after passing through the light-transmitting portion 1A. D ). The film thickness of the correction film 4 is set to 80 nm, and the depth of the digging into the light-transmitting portion 1B is set to 200 nm. In addition, optical simulations were performed for the correction film 4 formed in the correction hole portion 3B with a size (width) of 1 μm, 2 μm, 3 μm, and 5 μm and the hole portion 3A.

[0163] Figure 4 FIG. 2 is a diagram showing an aerial image of light intensity formed on a transfer object when a phase shift mask according to Example 2 of the present invention is used. Figure 4 , the results of optical simulations of the hole portion and the correction hole portion 3B of the phase shift film 2 in Example 2 are shown.

[0164] like Figure 4 As shown, in the correction hole portion 3B formed by the correction film 4 of any size in Example 2, the absolute value of the peak light intensity or the inclination of the peak formation is consistent with the profile of the hole portion 3A ( Figure 4 "Ref") is equal to or greater than that of the hole portion 3A and has a preferred profile that is equal to or greater than that of the hole portion 3A.

[0165] In addition, similarly to Example 1, the results of evaluating the optical performance of the phase shift mask of Example 3 are shown in Table 2 (Table 2 selects the cases where the size (width dimension) of the correction film 4 is set to 1 μm, 2 μm, and 5 μm).

[0166] [Table 2]

[0167]

[0168] As shown in Table 2, the correction hole 3B in Example 2 having the light-transmitting portion 1B dug into it has a good or comparable value for DOF compared to the hole 3A. It has a better value for MEEF than the hole 3A. It has a comparable value for EL as the hole 3A.

[0169] From this result, it can be said that even if the phase shift mask of Example 2 is placed on the mask stage of an exposure device and the resist film transferred to the display device is exposed, the hole pattern finally formed on the display device can be formed with high accuracy.

[0170] (Comparative Example 1)

[0171] like Figure 1 As shown, the phase shift mask of Comparative Example 1 includes a phase shift film having a transfer pattern formed on a light-transmitting substrate. The phase shift film has a transmittance T of 16% for exposure light having a typical wavelength of 334 nm. P and a phase difference of 180 degrees Φ P The transfer pattern includes a hole portion consisting of a light-transmitting portion in a hole shape and a correction hole portion having a light-transmitting portion. The size (one side of the square) of the light-transmitting portion of the hole portion and the light-transmitting portion of the correction hole portion is 2.4 μm. The correction film has a transmittance T of 16% for exposure light representing a wavelength of 334 nm. M and a phase difference of 85 degrees Φ M (In the comparative example, the correction hole portion is not dug.) The film thickness of the correction film was set to 70 nm. In addition, optical simulations were performed for the correction film formed in the correction hole portion with a size (width) of 1 μm, 1.5 μm, 2 μm, and 5 μm.

[0172] Figure 5 1 is a diagram showing an aerial image of light intensity formed on a transfer target when the phase shift mask of Comparative Example 1 of the present invention is used. Figure 5 , the results of optical simulation of the hole portion and the correction hole portion of the phase shift film in Comparative Example 1 are shown.

[0173] like Figure 5 As shown, the absolute value of the peak light intensity of the correction film formed in the correction hole portion is relative to the hole portion profile ( Figure 5 The "Ref") becomes lower, and there are large deviations in the inclination of the peak forming the transmitted light intensity, all of which are outside the allowable range.

[0174] Based on this result, it is expected that even if the phase shift mask of Comparative Example 1 is placed on the mask stage of an exposure device and the resist film transferred to the display device is exposed, the hole pattern finally formed on the display device cannot be formed with sufficient accuracy.

Claims

1. A phase shift mask comprising a phase shift film on a light-transmitting substrate, wherein the phase shift film is formed with a transfer pattern including a correction hole portion, characterized in that: The correction hole portion includes: a hollowed-out light-transmitting portion having a hole shape formed by hollowing out the surface of the light-transmitting substrate; a correction film formed to surround the outer periphery of the hollowed-in light-transmitting portion; and a phase shift film formed to surround the correction film, The phase difference Φ generated between the exposure light after passing through the phase shift film and the exposure light after passing through the air at a distance equal to the film thickness of the phase shift film is P is 150 degrees or more and 210 degrees or less, The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the air at a distance equal to the film thickness of the correction film is M is smaller than the phase difference Φ P , The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the hollowed-in light-transmitting portion H is 150 degrees or more and 210 degrees or less, The transmittance T of the correction film to the exposure light M The transmittance T of the phase shift film to the exposure light P The difference is less than 2%.

2. The phase-shift mask according to claim 1, characterized in that: The transmittance T of the phase shift film P More than 10%.

3. The phase-shift mask according to claim 1, characterized in that: The transmittance T of the correction film M More than 10%.

4. The phase-shift mask according to claim 1, characterized in that: The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the air at a distance equal to the film thickness of the correction film is M Below 100 degrees.

5. The phase-shift mask according to claim 1, characterized in that: The exposure light includes at least light having a wavelength of 365 nm.

6. A method for manufacturing a phase shift mask, wherein the phase shift mask comprises a phase shift film having a transfer pattern formed on a light-transmitting substrate, wherein: The manufacturing method comprises the following steps: forming a transfer pattern on the phase shift film disposed on the light-transmitting substrate, the transfer pattern including a hole portion consisting of a light-transmitting portion in a hole shape; Performing defect inspection on the transfer pattern of the phase shift film to determine a hole portion having a defect; as well as Correct the defects, The step of correcting the defect includes: forming a correction film on the hole portion having the defect so as to surround the outer periphery of the light-transmitting portion; and a step of digging into the surface of the light-transmitting substrate of the light-transmitting portion to form a dug light-transmitting portion, The phase difference Φ generated between the exposure light after passing through the phase shift film and the exposure light after passing through the air at a distance equal to the film thickness of the phase shift film is P is 150 degrees or more and 210 degrees or less, The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the air at a distance equal to the film thickness of the correction film is M is smaller than the phase difference Φ P , The phase difference Φ generated between the exposure light after passing through the correction film and the exposure light after passing through the hollowed-in light-transmitting portion H is 150 degrees or more and 210 degrees or less, The transmittance T of the correction film to the exposure light M The transmittance T of the phase shift film to the exposure light P The difference is less than 2%.

7. The method for manufacturing a phase-shift mask according to claim 6, characterized in that: The transmittance T of the phase shift film P More than 10%.

8. The method for manufacturing a phase-shift mask according to claim 6, characterized in that: The transmittance T of the correction film M More than 10%.

9. The method for manufacturing a phase-shift mask according to claim 6, characterized in that: The exposure light includes at least light having a wavelength of 365 nm.

10. A method for manufacturing a display device, characterized in that: The process is as follows: placing the phase shift mask according to any one of claims 1 to 5 on a mask stage of an exposure device; and The phase shift mask is irradiated with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device.

11. A method for manufacturing a display device, characterized in that: The process is as follows: placing the phase shift mask manufactured by the method for manufacturing a phase shift mask according to any one of claims 6 to 9 on a mask stage of an exposure device; and The phase shift mask is irradiated with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device.

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