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

Abstract

To provide an excellent phase shift mask capable of advantageously adopting to an exposure environment of a mask for manufacturing a display device and capable of stably transferring a fine hole pattern.SOLUTION: A phase shift mask includes a phase shift film with a transfer pattern including a correction hole part formed on a light transmissive substrate. The correction hole part includes: an engraved light transmissive part in a hole shape where a surface of the light transmissive substrate is engraved; a correction film formed so as to surround a circumference of the engraved light transmissive part; and a phase shift film formed so as to surround a circumference of the correction film. A phase difference ΦP occurring at the exposure light having passed through the phase shift film is 150 to 210 degrees. A phase difference ΦM occurring at the exposure light having passed through the correction film is smaller than the phase difference ΦP. A phase difference ΦH occurring between the exposure light having passed through the correction film and the exposure light having passed through the engraved light transmissive part is 150 to 210 degrees. A difference between a transmittance TM of the correction film to the exposure light and a transmittance TP of the phase shift film to the exposure light is 2% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] In recent years, display devices such as FPDs (Flat Panel Displays) represented by OLEDs (Organic Light Emitting Diodes) have rapidly advanced in terms of increasing screen size, widening viewing angles, and flexibility (e.g., folding), as well as increasing definition and display speed. One of the elements required for achieving this high definition and high display speed is the fabrication of electronic circuit patterns such as elements and wiring with fine and high dimensional accuracy. Photolithography is often used for patterning the electronic circuits for display devices. For this reason, a phase shift mask with fine and high-precision patterns is required for display device manufacturing. This phase shift mask is made by forming the parts equivalent to the light-shielding parts of a binary mask using a halftone film with low transmittance and a phase shift of 180 degrees.

[0003] For example, Patent Document 1 describes a method for manufacturing a phase shift mask having a transfer pattern including a semi-transparent portion formed by patterning a semi-transparent film 2 on a transparent substrate 1, in which the semi-transparent portion 12 has a predetermined transmittance and a phase difference of approximately 180 degrees with respect to a representative wavelength of exposure light, the method including a correction film formation step of forming a correction film 4 in a predetermined area including a defect in the semi-transparent portion, the correction film being 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. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-20120 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, in the case of a thin film transistor ("TFT") used in the display device, if the contact hole formed in the interlayer insulating film among the multiple patterns constituting the TFT does not reliably connect the upper and lower patterns, correct operation is not guaranteed. On the other hand, in order to maximize the aperture ratio of the display device and make it a bright and power-saving display device, the diameter of the contact hole is required to be sufficiently small. Accordingly, it is desired that the diameter of the hole pattern provided in the photomask for forming such contact holes is also finer (for example, less than 3 μm). For example, a hole pattern with a diameter of 2.5 μm or less, or even 2.0 μm or less, is required, and it is considered that in the near future, the formation of a pattern with a diameter smaller than this, 1.5 μm or less, is also desired. In this background, a manufacturing technology for a display device that can reliably transfer minute contact holes is required.

[0006] For example, when a defect occurs in a pattern portion formed by a phase shift film of a halftone phase shift mask, it is not necessarily easy to repair the defect. In general, when a defect occurs in a phase shift mask and is to be repaired by a repair film, it is known to use an FIB (focused ion beam) device as a repairing means. However, it has been found that the method of simply depositing a repair film on a defective portion of a phase shift mask using an FIB device may not be able to restore the same functionality as a phase shift mask without defects.It has been found that even if a repair film is deposited on a defective portion of a phase shift mask using an FIB device, it is not easy to form a repair film that has a phase shift amount of approximately 180 degrees with respect to the exposure light and a desired transmittance set for the phase shift film on the normal portion. On the other hand, a method using a laser CVD method is also known for repairing defects in a phase shift mask that forms a semi-transmitting portion. However, in the case of the laser CVD method, a process of removing the deposited repair film by wet etching is unavoidable, and it is difficult to repair defects in a minute hole pattern with the desired accuracy.

[0007] The present invention has been made to solve the above-mentioned problems. That is, an object of the present invention is to provide an excellent phase shift mask that is advantageously suited to the exposure environment of a mask for manufacturing a display device and is capable of stably transferring a fine hole pattern, a method for manufacturing the same, and a method for manufacturing a display device. [Means for solving the problem]

[0008] The present invention has the following configuration as a means for solving the above problems.

[0009] (Configuration 1) A phase shift mask having a phase shift film on a light-transmitting substrate, the phase shift film having a transfer pattern including a correction hole portion formed thereon, the correction hole portion includes a carved light-transmitting portion having a hole shape formed by carving a surface of the light-transmitting substrate, a correction film formed so as to surround an outer periphery of the carved light-transmitting portion, and a phase shift film formed so as to surround the correction film; The phase difference Φ between the exposure light transmitted through the phase shift film and the exposure light transmitted through air a distance equal to the thickness of the phase shift film. P is between 150 and 210 degrees, The phase difference Φ between the exposure light transmitted through the correction film and the exposure light transmitted through air a distance equal to the thickness of the correction film M is the phase difference Φ P Smaller than A phase difference Φ generated between the exposure light transmitted through the correction film and the exposure light transmitted through the carved light transmitting portion H is between 150 and 210 degrees, The transmittance T of the correction film for the exposure light M and the transmittance T of the phase shift film for the exposure light.P The phase shift mask according to claim 1, wherein the difference between the first and second phase shift masks is 2% or less.

[0010] (Configuration 2) The transmittance T of the phase shift film P 2. The phase shift mask according to claim 1, wherein the difference is 10% or more.

[0011] (Configuration 3) Transmittance T of the correction film M 2. The phase shift mask according to claim 1, wherein the difference is 10% or more.

[0012] (Configuration 4) A phase difference Φ between the exposure light transmitted through the correction film and the exposure light transmitted through air a distance equal to the thickness of the correction film M 2. The phase shift mask according to claim 1, wherein the angle is 100 degrees or less. (Configuration 5) The phase shift mask according to configuration 1, wherein the exposure light includes at least light having a wavelength of 365 nm.

[0013] (Configuration 6) A method for manufacturing a phase shift mask having a phase shift film on a light-transmitting substrate, the method comprising the steps of: forming a transfer pattern including a hole portion formed of a hole-shaped light-transmitting portion in the phase shift film provided on the light-transmitting substrate; a step of performing a defect inspection on the transfer pattern of the phase shift film to identify a hole portion having a defect; Repairing the defect, The step of repairing the defect includes a step of forming a repair film for a hole portion in which the defect exists so as to surround an outer periphery of the light-transmitting portion, and a step of digging a surface of the light-transmitting substrate of the light-transmitting portion to form a dug-in light-transmitting portion, The phase difference Φ between the exposure light transmitted through the phase shift film and the exposure light transmitted through air a distance equal to the thickness of the phase shift film. P is between 150 and 210 degrees, The phase difference Φ between the exposure light transmitted through the correction film and the exposure light transmitted through air a distance equal to the thickness of the correction filmM is the phase difference Φ P Smaller than A phase difference Φ generated between the exposure light transmitted through the correction film and the exposure light transmitted through the carved light transmitting portion H is between 150 and 210 degrees, The transmittance T of the correction film for the exposure light M and the transmittance T of the phase shift film for the exposure light. P The method for manufacturing a phase shift mask is characterized in that the difference between the above and the above is 2% or less.

[0014] (Configuration 7) The transmittance T of the phase shift film P 7. The method for producing a phase shift mask according to structure 6, wherein the difference is 10% or more.

[0015] (Configuration 8) Transmittance T of the correction film M 7. The method for producing a phase shift mask according to structure 6, wherein the difference is 10% or more. (Configuration 9) The method for producing a phase shift mask according to configuration 6, wherein the exposure light includes at least light having a wavelength of 365 nm.

[0016] (Configuration 10) A step of placing the phase shift mask according to any one of configurations 1 to 5 on a mask stage of an exposure tool; a step of irradiating the phase shift mask with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device; A method for manufacturing a display device comprising the steps of:

[0017] (Configuration 11) A step of placing a phase shift mask manufactured by the method for manufacturing a phase shift mask according to any one of configurations 6 to 9 on a mask stage of an exposure tool; a step of irradiating the phase shift mask with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device; A method for manufacturing a display device comprising the steps of: Effect of the Invention

[0018] According to the present invention, it is possible to provide an excellent phase shift mask which is advantageously suited to the exposure environment of a mask for manufacturing a display device and capable of stably transferring a fine hole pattern, a method for manufacturing the same, and a method for manufacturing a display device. [Brief description of the drawings]

[0019] [Figure 1] 1A and 1B are a schematic plan view and a schematic cross-sectional view of an example of a phase shift mask according to a first embodiment of the present invention. [Diagram 2] 13A and 13B are a schematic plan view and a schematic cross-sectional view of another example of a phase shift mask according to the second embodiment of the present invention. [Diagram 3] FIG. 4 is a diagram showing an aerial image of light intensity formed on a transferred object when the phase shift mask according to the first embodiment of the present invention is used. [Figure 4] FIG. 11 is a diagram showing an aerial image of light intensity formed on a transfer target when a phase shift mask according to a second embodiment of the present invention is used. [Diagram 5] FIG. 13 is a diagram showing an aerial image of light intensity formed on a transfer target when a phase shift mask according to a comparative example of the present invention is used. [Figure 6] 1 is a graph showing the relationship between phase difference and transmittance for light with a wavelength of 334 nm in a repair film formed by the repair device (FIB device) used in the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First, the background to the completion of the present invention will be described. The present inventors have conducted extensive research into the configuration of an excellent phase shift mask that is advantageously suited to the exposure environment of a mask for manufacturing a display device and that can stably transfer a fine hole pattern. The FIB device mainly uses gallium ions to deposit a carbon-based film. The present inventor investigated the relationship between phase difference and transmittance for a repair film formed by a current FIB device. The results are shown in FIG. 6. FIG. 6 is a graph showing the relationship between phase difference and transmittance for light with a wavelength of 334 nm in a repair film formed by a repair device (FIB device) used in an embodiment of the present invention. As shown in FIG. 6, the phase difference and the transmittance are inversely proportional to each other, and it is difficult to achieve both a desired phase difference (for example, 180 degrees) and a desired transmittance (for example, 10%) in this repair film. The graph showing the relationship between phase difference and transmittance of the repair film has approximately the same tendency in the case of i-line (wavelength 365 nm) light. The graph showing the relationship between phase difference and transmittance of the repair film also has a similar inverse proportional tendency in the case of h-line (wavelength 405 nm) light. Even when repairing a pattern of a phase shift film with a higher transmittance in h-line exposure light using this repair film, it is difficult to achieve both a desired phase difference and a desired transmittance.

[0021] Therefore, the inventor changed his idea and investigated whether it would be possible to stably transfer a fine hole pattern by forming a correction film formed by a current FIB device so that only either the phase difference or the transmittance is within a desired range. As a result, he found that by forming a correction film so that the transmittance is within a desired range and by forming a correction hole part so as to secure a desired phase difference by digging into the surface (transparent part) of the transparent substrate surrounded by the correction film, it is possible to obtain performance comparable to that of a hole part formed in a phase shift film and stably transfer a fine hole pattern. The phase shift mask of the present invention has been arrived at as a result of the above-mentioned extensive research.

[0022] <Phase Shift Mask of the First Embodiment> An example of a phase shift mask according to the first embodiment of the present invention is shown in Figure 1. Figure 1(a) is a schematic plan view, and Figure 1(b) is a schematic cross-sectional view. As shown in FIG. 1, the phase shift mask 100 comprises 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 a correction hole portion formed on the light-transmitting substrate 1. The correction hole portion 3B is composed of an engraved light-transmitting portion 1B having a hole shape formed by engraving the surface of the light-transmitting substrate 1, a correction film 4 formed so as to surround the outer periphery of the engraved light-transmitting portion 1B, and a phase shift film 2 formed so as to surround the correction film 4. The transfer pattern (phase shift pattern) in this embodiment includes a hole portion 3A composed of a non-engraved hole-shaped light-transmitting portion 1A (hereinafter, may be simply referred to as "light-transmitting portion 1A") formed in the phase shift film 2 as shown in Fig. 1 (hereinafter, the non-engraved hole portion 3A may be simply referred to as "hole portion 3A").

[0023] The size of the light transmitting portion 1A of the hole portion 3A is preferably 4.0 μm or less, more preferably 3.0 μm or less, and even more preferably 2.5 μm or less. On the other hand, the size of the light transmitting portion 1A of the hole portion 3A is preferably 0.8 μm or more. Similarly to the hole portion 3A, the size of the carved light transmitting portion 1B of the correction hole portion 3B is preferably 4.0 μm or less, more preferably 3.0 μm or less, and even more preferably 2.5 μm or less. On the other hand, the size of the carved light transmitting portion 1B of the correction hole portion 3B is preferably 0.8 μm or more.

[0024] In FIG. 1, the shape of the holes 3A and 3B is shown to be substantially square in plan view, but is not limited thereto. The shape of the holes 3A and 3B may be other shapes such as a rectangle, a polygon, a circle, an ellipse, etc. When the shape of the holes 3A and 3B is substantially square, the size means the length of one side. When the shape of the holes is rectangular, the size means the length of the long side. When the shape of the holes 3A and 3B is polygonal, the size means the diameter of a circle inscribed in the polygon. When the shape of the holes 3A and 3B is circular, the size means the diameter. When the shape of the holes 3A and 3B is elliptical, the size means the length of the major axis (major axis).

[0025] The light-transmitting substrate 1 is transparent to the exposure light. The light-transmitting substrate 1 has a transmittance of 85% or more, preferably 90% or more, to the exposure light, assuming that there is no surface reflection loss. The light-transmitting substrate 1 is made of a material containing silicon and oxygen, and can be made of glass materials such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda-lime glass, and low-thermal expansion glass (SiO2-TiO2 glass, etc.).

[0026] 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 suitable, and titanium and molybdenum are more preferable. The phase shift film may be made of a material containing chromium (Cr), for example, a chromium-based material containing Cr and at least one of oxygen (O) and nitrogen (N). Specific examples include CrO, CrN, CrON, etc. The phase shift film 2 is preferably one that can be wet etched.

[0027] As the exposure light, for example, light having a wavelength range of 300 to 500 nm can be used. As the light source of an exposure device for manufacturing a display device, for example, a light source including any one or more of i-line, h-line, and g-line (for example, a high-pressure mercury lamp) can be suitably used. The representative wavelength of the exposure light can be any wavelength included in the above wavelength range. In addition, when it is desired to shift the center of gravity of the wavelength range of the exposure light to the short wavelength side as the pattern becomes finer, light having a wavelength range on the shorter wavelength side than the above wavelength range (e.g., 250 to 400 nm) can be used as the exposure light, and for example, light having a wavelength range on the short wavelength side including two or more of 313 nm, 334 nm, and 365 nm can be used as the exposure light. Furthermore, light with a single wavelength of i-line (365 nm) can also be used as the exposure light. Thus, it is preferable that the exposure light contains at least light with a wavelength of 365 nm. In this specification, unless otherwise specified, the i-line (365 nm) is used as an example of a representative wavelength.

[0028] The phase shift film 2 has a phase shift effect for the representative wavelength of the exposure light. That is, there is a phase difference Φ between the exposure light that has passed through the phase shift film 2 and the exposure light that has passed through air a distance equal to the thickness of the phase shift film 2. P The phase difference Φ P is preferably about 180 degrees. In this specification, about 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, it is preferable that the phase shift film 2 has a phase difference of about 180 degrees for all of the main wavelengths (e.g., i-line, h-line, g-line) contained in the exposure light.

[0029] The transmittance of the phase shift film 2 to the exposure light satisfies a value required for the phase shift film 2. The transmittance T P is preferably 10% or more for the light of the representative wavelength contained in the exposure light. P is preferably 50% or less, and more preferably 40% or less, of the light having a representative wavelength contained in the exposure light.

[0030] In order to ensure optical performance, the thickness of the phase shift film 2 is preferably 200 nm or less, more preferably 180 nm or less, and even more preferably 150 nm or less. In order to ensure a desired transmittance, the thickness of the phase shift film 2 is preferably 50 nm or more, and more preferably 60 nm or more.

[0031] The phase shift film 2 can be formed by a known film formation method such as a sputtering method, etc. The transfer pattern can be formed by a known method using wet etching, etc.

[0032] The repair film 4 is formed in an area including a white defect in which the phase shift film 2 is missing. The repair film 4 is a metal film that is substantially free of oxygen, or a carbon-containing film. In this specification, "substantially free of oxygen" means that the O content is less than 5%.

[0033] When the repair film 4 is a carbon-containing film, the content of C is preferably 90 to 100%. This can improve chemical resistance. The repair film 4 may contain elements other than C (e.g., Ga, Si, W, Pt, Au, etc.). When the repair film is a metal film, it may be, for example, a film containing Mo or Cr.

[0034] The correction film 4 has a transmittance T M The transmittance T of the correction film 4 to the exposure light is M and the transmittance T of the phase shift film 2 for the exposure light. P The difference between the transmittance T of the correction film 4 and the transmittance T of the correction film 4 is preferably 2% or less (within a range of ±2%), and more preferably 1% or less (within a range of ±1%). M is preferably 10% or more. The phase difference Φ between the exposure light transmitted through the correction film 4 and the exposure light transmitted through air a distance equal to the thickness of the correction film 4 M is the phase difference Φ P The phase difference Φ M can be less than or equal to 100 degrees. M can be greater than 0 degrees.

[0035] The width of the repair film 4 is sufficient to ensure a width within a range in which a white defect can be repaired, and is preferably 0.4 μm or more. Also, the width of the repair film 4 is preferably 10 μm or less.

[0036] In order to achieve the above optical characteristics, the thickness of the repair film 4 is preferably 90 nm or less, more preferably 80 nm or less. On the other hand, the thickness of the repair film 4 is preferably 30 nm or more, more preferably 50 nm or more. The correction film 4 can be formed by using an FIB device.

[0037] The repair hole portion 3B is a carved light transmitting portion 1B having a hole shape formed by carving the surface of the light transmitting substrate 1. There is a phase difference Φ of approximately 180 degrees (150 degrees or more and 210 degrees or less) between the exposure light transmitted through the correction film 4 and the exposure light transmitted through the recessed light transmitting portion 1B. H The phase difference Φ H is 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 difference Φ D is preferably 50 degrees or more and 140 degrees or less, more preferably 65 degrees or more and 125 degrees or less, and even more preferably 80 degrees or more and 110 degrees or less. The depth of the dug light transmitting portion 1B of the correction hole portion 3B is set to the above phase difference Φ H , Φ D It is preferable that the depth is set so that It is preferable that the size (width dimension) of the carved light transmitting portion 1B of the repair hole portion 3B is the same as that of the light transmitting portion 1A of the hole portion 3A. The carved light transmitting portion 1B can be formed by using, for example, an FIB device.

[0038] By configuring the correction hole portion 3B in this manner, it is possible to ensure a phase difference and transmittance that are comparable to those of the hole portion 3A in the light transmitting portion 1A, and it is possible to exhibit a good phase shifting function.

[0039] The phase shift mask 100 in the first embodiment of the present invention has the above-mentioned configuration, making it an excellent phase shift mask 100 that is advantageously suited to the exposure environment of masks for manufacturing display devices and can stably transfer fine hole patterns.

[0040] In this embodiment, a transfer pattern including hole portions 3A and correction hole portions 3B is described, but this is not necessarily limited to this, and for example, the hole patterns of the transfer pattern may all be composed of correction hole portions 3B. In addition, in FIG. 1, the shape of these holes is shown to be approximately square when viewed from above, but this is not limited to this and may be other shapes such as polygonal, circular, or elliptical (the same applies to the following embodiments).

[0041] <Phase Shift Mask of the Second Embodiment> Another example of a phase shift mask according to the second embodiment of the present invention is shown in Fig. 2. Fig. 2(a) is a schematic plan view, and Fig. 2(b) is a schematic cross-sectional view. The matters relating to the light-transmitting substrate 1, phase shift film 2, correction film 4, hole portion 3A, and correction hole portion 3B in the phase shift mask 110 of the second embodiment are the same as those in the first embodiment, so the description thereof will be omitted. 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. This light-shielding film 5 has a light-shielding pattern including a light-shielding band in an area other than the transfer pattern (FIG. 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 repair film 4 constituting the repair hole portion 3B).

[0042] The light-shielding film 5 is disposed above the phase shift film 2, and is made of a material that has etching resistance to the etching solution that etches the phase shift film 2 (has etching selectivity different from that of the phase shift film 2). 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 not containing silicon. Substantially not containing silicon means that the silicon content is less than 2%. More specifically, the chromium-based material may be a material containing chromium (Cr) or chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C). In addition, the chromium-based material may be a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C), and further containing fluorine (F). For example, the material constituting the light-shielding film 5 may be Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF.

[0043] The light-shielding film 5 can be formed by a known film-forming method such as a sputtering method.

[0044] The light-shielding film 5 has a function of blocking the transmission of exposure light, and the optical density with respect to the exposure light in the portion where the phase shift film 2 and the light-shielding film 5 are laminated is preferably 3 or more, more preferably 3.5 or more, and further preferably 4 or more. In this embodiment, the light-shielding film 5 is provided on the phase shift film 2, but it may be an etching mask film having an etching selectivity different from that of the phase shift film 2. In this case, it is preferable that the light-shielding film is a low-transmittance film having a lower transmittance than the phase shift film.

[0045] 2 has a configuration in which the phase shift film 2 and the light-shielding film 5 are laminated in this order on the light-transmitting substrate 1, but the light-shielding film 5 may be laminated in this order on the phase shift film 2. In this case, since the light-shielding film 5 having a light-shielding pattern is first formed on the light-transmitting substrate 1, the phase shift film 2 can be laminated and the phase shift pattern can be formed, and therefore etching selectivity does not need to be present between the phase shift film 2 and the light-shielding film 5.

[0046] By virtue of having the above-described configuration, phase shift mask 110 in the second embodiment of the present invention can be an excellent phase shift mask that is advantageously suited to the exposure environment of masks for manufacturing display devices and can stably transfer fine hole patterns.

[0047] Next, a method for producing a phase shift mask according to the present invention will be described. The method for producing a phase shift mask of the present invention is a method for producing a phase shift mask including a phase shift film having a transfer pattern formed on a light-transmitting substrate, the method comprising the steps of: forming a transfer pattern including a hole portion composed of a hole-shaped light-transmitting portion in a phase shift film provided on a light-transmitting substrate; a step of performing a defect inspection on the transferred pattern of the phase shift film to identify holes having defects; and correcting the defect, The process of repairing the defect includes a process of forming a repair film around the outer periphery of the light-transmitting portion of the hole where the defect exists, and a process of digging into the surface of the light-transmitting substrate of the light-transmitting portion to form a dug-in light-transmitting portion.

[0048] <Method of manufacturing the phase shift mask according to the first embodiment> When manufacturing phase shift mask 100 of the first embodiment, a mask blank is prepared in which a phase shift film is formed on a light-transmitting substrate. The specific configurations of the light-transmitting substrate and phase shift film formed in the mask blank are similar to those of light-transmitting substrate 1 and phase shift film 2 formed in phase shift mask 100 of the first embodiment, except that no transfer pattern is formed. Then, a transfer pattern including hole portions 3A consisting of hole-shaped light-transmitting portions is formed in 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 holes formed from the resist film as a mask, thereby forming a transfer pattern including hole portions 3A in the phase shift film 2. A defect inspection is carried out on the transferred pattern of the phase shift film 2 to identify the hole portion 3A in which a defect exists. A step of repairing the defect is carried out on the hole 3A where the defect exists. The process of repairing the defect includes a process of forming a repair film 4 around the outer periphery of the light-transmitting portion 1A in the hole portion 3A where the defect exists, and a process of digging into the surface of the light-transmitting substrate 1 of the light-transmitting portion 1A to form a dug-in light-transmitting portion 1B.

[0049] The repair film 4 can be formed by using an FIB device. A known FIB device can be used as the FIB device for forming the repair film 4. For example, Ga (gallium) can be used as the ion source. The source gas for forming the repair film 4 by the FIB method is, for example, pyrene (C 16 H 10 ), phenanthrene (C 14 H 10 Gases containing hydrocarbon compounds such as styrene (C8H8), gases 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), (MeCp)PtMe3 gas called (trimethyl)methylcyclopentadienyl platinum (IV), and copper(+1) hexafluoro acethylacetonate trimethylvinylsilane called Cu(hfac)TMVS can be used. In this embodiment, a case where pyrene is used as the raw material gas will be described. Examples of source gases for Mo-containing films include MoF6, Mo(CO)6, MoCl5, etc. Examples of source gases for Cr-containing films include Cr(C6H6)2, etc.

[0050] Using an FIB device, the transmittance T of the phase shift film 2 for the exposure light is measured for the representative wavelength of the exposure light. P The difference between the transmittance and the transmittance T is 2% or less. M The correction film 4 is formed to a predetermined thickness so that the correction film 4 has a phase difference Φ M is the phase difference Φ of the phase shift film 2 with respect to the exposure light P (See Figure 6.)

[0051] The engraved light transmitting portion 1B can be formed by using an FIB device. As an ion source, for example, Ga (gallium) can be used. There are no particular limitations on the source gas for forming the recessed light-transmitting portion 1B by the FIB method, so long as it has the property of being able to etch the light-transmitting substrate 1. For example, a fluorine-based etching gas can be used. Using an FIB device, the phase difference Φ generated between the exposure light transmitted through the repair film 4 and the exposure light transmitted through the engraved light-transmitting portion 1B is H A carved light transmitting portion 1B having a predetermined depth and a predetermined width is formed so that the angle is 150 degrees or more and 210 degrees or less. The step of forming the repair film 4 and the step of forming the engraved light transmitting portion 1B may be performed in either order, or may be performed in parallel. In this manner, it is possible to manufacture phase shift mask 100 of the first embodiment, which is provided with phase shift film 2 on which a transfer pattern including correction hole portion 3B is formed.

[0052] <Method of manufacturing a phase shift mask according to the second embodiment> When manufacturing the phase shift mask of the second embodiment, a mask blank is prepared in which a phase shift film and a light-shielding film are formed on a light-transmitting substrate. The specific configurations of the light-transmitting substrate, phase shift film, and light-shielding film formed in the mask blank are the same as those of the light-transmitting substrate 1, phase shift film 2, and light-shielding film 5 formed in the phase shift mask 110 of the second embodiment, except that no transfer pattern or light-shielding pattern is formed. Then, a light-shielding pattern is formed on the light-shielding film 5, and a transfer pattern including a hole portion consisting of a hole-shaped light-transmitting portion 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 from 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 has been formed as a mask, thereby forming a transfer pattern 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 the light-shielding pattern including the light-shielding band formed from the second resist film as a mask, thereby forming a light-shielding pattern on the light-shielding film 5.

[0053] A defect inspection is carried out on the transferred pattern of the phase shift film 2 to identify the hole portion 3A in which a defect exists. For hole portion 3A having a defect, a process of repairing the defect and forming repaired hole portion 3B is carried out as follows.

[0054] In the same manner as in the case of manufacturing the phase shift mask 100 of the first embodiment, the transmittance T of the phase shift film 2 for the exposure light is measured using an FIB device. P The transmittance T of the phase shift film 2 for the exposure light is set to 2% or less. P The difference between the transmittance and the transmittance T is 2% or less. M The correction film 4 is formed to a predetermined thickness so that the correction film 4 has a phase difference Φ M is the phase difference Φ of the phase shift film 2 with respect to the exposure light P (See Figure 6) Then, in the same manner as in the case of manufacturing the phase shift mask 100 of the first embodiment, a phase difference Φ H A carved light transmitting portion 1B having a predetermined depth and a predetermined width is formed so that the angle is 150 degrees or more and 210 degrees or less. In this manner, it is possible to manufacture phase shift mask 110 of the second embodiment, which includes phase shift film 2 on which a transfer pattern including correction hole portion 3B is formed.

[0055] <Display Device Manufacturing Method> The manufacturing method of the display device of this embodiment will be described. The manufacturing method of the display device of this embodiment includes a step of placing the phase shift mask according to any of the above-mentioned embodiments or a phase shift mask manufactured by the manufacturing method of the phase shift mask according to any of the above-mentioned embodiments on a mask stage of an exposure tool, 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. Each step will be described in detail below.

[0056] In the placing step, the phase shift mask according to the above-described embodiment is placed on a mask stage of an exposure tool. Here, the phase shift mask is disposed so as to face a resist film formed on a substrate for a display device via a projection optical system of the exposure tool.

[0057] In the pattern transfer process, the phase shift mask is irradiated with exposure light to transfer a transfer pattern including a thin film pattern for pattern formation to a resist film formed on a substrate for a display device. The exposure light is a composite light including a plurality of wavelengths selected from a wavelength range of 313 nm to 436 nm, or a monochromatic light selected by cutting a certain wavelength range from the wavelength range of 313 nm to 436 nm using a filter or the like, or a monochromatic light emitted from a light source having a wavelength range of 313 nm to 436 nm. For example, the exposure light is a composite light including at least one of i-rays, h-rays, and g-rays, or a monochromatic light of i-rays. By using a composite light as the exposure light, the exposure light intensity can be increased to improve the throughput. Therefore, the manufacturing cost of the display device can be reduced.

[0058] According to the manufacturing method of the display device of this embodiment, a high-resolution, high-definition display device having fine contact holes can be manufactured. EXAMPLES

[0059] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0060] The transfer performance of the phase shift mask of this embodiment was compared and evaluated by optical simulation. That is, an optical simulation was performed to determine the transfer performance of a phase shift mask having a transfer pattern for forming a hole pattern with a diameter of 1.5 μm on a transfer target object when the exposure conditions were set to the same value.

[0061] Example 1 1, 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 P and a phase difference of 180 degrees Φ P The transfer pattern includes a hole portion 3A consisting of a hole-shaped light-transmitting portion 1A and a correction hole portion 3B having a carved light-transmitting portion 1B. The size (one side of a square) of the light-transmitting portion 1A of the hole portion 3A and the carved 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 with a representative wavelength of 334 nm. M and a phase difference of 85 degrees Φ P and has a phase difference Φ of 180 degrees with the exposure light transmitted through the recessed light transmitting portion 1B. H (That is, the recessed light-transmitting portion 1B has a phase difference Φ of 95 degrees with the exposure light transmitted through the light-transmitting portion 1A.) D The thickness of the repair film 4 is 70 nm, and the depth of the carved light transmitting portion 1B is 240 nm. In addition, optical simulations were performed for repair film 4 formed in repair hole portion 3B with sizes (width dimensions) of 1 μm, 2 μm, 3 μm, and 5 μm, and for hole portion 3A.

[0062] 3 is a diagram showing an aerial image of light intensity formed on a transfer target when phase shift mask 100 according to the first embodiment of the present invention is used. Fig. 3 shows the results of an optical simulation of hole 3A and correction hole 3B of phase shift film 2 according to the first embodiment. For example, to transfer a fine light-transmitting pattern with a small diameter, the exposure light that passes through the photomask must have a good aerial image on the transferred object, i.e., a good profile of the transmitted light intensity curve. Specifically, it is essential that the slope forming the peak of the transmitted light intensity is sharp and rises nearly vertically, and that the absolute value of the peak light intensity is high (if sub-peaks are formed around it, the intensity must be sufficiently high relative to those peaks).

[0063] As shown in FIG. 3, in the repair hole portion 3B formed with the repair film 4 of any size in Example 1, the absolute value of the peak light intensity and the slope forming the peak were equal to or greater than those of the profile of the hole portion 3A ("Ref" in FIG. 3), and the repair hole portion 3B had a preferable profile equal to or greater than those of the hole portion 3A.

[0064] To more quantitatively evaluate a phase shift mask from the viewpoint of optical performance, the following indices can be used. (1) Depth of focus (DOF) The depth of focus required to achieve a target CD (Critical Dimension) within a range of ±10%. The higher the DOF value, the less the effect of the flatness of the target object (such as a display panel substrate) will be, allowing fine patterns to be formed reliably and CD (line width) variations to be suppressed. (2) MEEF (Mask Error Enhancement Factor) A value that indicates the ratio of the Mask CD error to the CD error of the pattern formed on the recipient. The lower the MEEF, the more the CD error of the pattern formed on the recipient can be reduced. (3) Exposure latitude (EL) This represents the percentage of exposure tolerance that satisfies the panel CD target of 1.5μm ±10% CD variation. The phase shift mask of Example 1 was evaluated for these items and the results are shown in Table 1 (Table 1 excerpts show repair film 4 sizes (widths) of 1 μm, 2 μm, and 5 μm).

[0065] [Table 1] As shown in Table 1, the modified hole portion 3B in Example 1 in which the carved light transmitting portion was formed had a good or comparable value for DOF compared to the hole portion 3A. A better value for MEEF was obtained than the hole portion 3A. A value comparable for EL was also obtained compared to the hole portion 3A.

[0066] From these results, it can be said that even if the phase shift mask of Example 1 is set on the mask stage of an exposure tool and exposed and transferred onto a resist film on a display device, the hole pattern that is ultimately formed on the display device can be formed with high precision.

[0067] Example 2 1, 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 P and a phase difference of 180 degrees Φ P The transfer pattern includes a hole portion 3A consisting of a hole-shaped light-transmitting portion 1A and a correction hole portion 3B having a carved light-transmitting portion 1B. The size (one side of a square) of the light-transmitting portion 1A of the hole portion 3A and the carved 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 with a representative wavelength of 334 nm. M and a phase difference of 105 degrees Φ P and has a phase difference Φ of 180 degrees with the exposure light transmitted through the recessed light transmitting portion 1B. H (That is, the recessed light-transmitting portion 1B has a phase difference Φ of 75 degrees with the exposure light transmitted through the light-transmitting portion 1A.) DThe thickness of the repair film 4 is 80 nm, and the depth of the carved light transmitting portion 1B is 200 nm. In addition, optical simulations were performed for repair film 4 formed in repair hole portion 3B with sizes (width dimensions) of 1 μm, 2 μm, 3 μm, and 5 μm, and for hole portion 3A.

[0068] 4 is a diagram showing an aerial image of light intensity formed on a transfer target when using the phase shift mask of Example 2 of the present invention. In FIG. 4, the results of an optical simulation of the hole portion of phase shift film 2 and correction hole portion 3B in Example 2 are shown. As shown in FIG. 4, in the repair hole portion 3B formed with the repair film 4 of any size in Example 2, the absolute value of the peak light intensity and the slope forming the peak were equal to or greater than those of the profile of the hole portion 3A ("Ref" in FIG. 4), and the repair hole portion 3B had a preferable profile equal to or greater than those of the hole portion 3A.

[0069] As in Example 1, the phase shift mask of Example 3 was evaluated for optical performance, and the results are shown in Table 2 (Table 2 excerpts the masks with the correction film 4 having sizes (width dimensions) of 1 μm, 2 μm, and 5 μm).

[0070] [Table 2] As shown in Table 2, the modified hole portion 3B in Example 2 in which the carved light transmitting portion 1B was formed had a good or comparable value for DOF compared to the hole portion 3A. A better value for MEEF was obtained than the hole portion 3A. A value comparable for EL was also obtained compared to the hole portion 3A.

[0071] From these results, it can be said that even if the phase shift mask of Example 2 is set on the mask stage of an exposure tool and exposed and transferred onto a resist film on a display device, the hole pattern that is ultimately formed on the display device can be formed with high precision.

[0072] Comparative Example 1 The phase shift mask of Comparative Example 1 includes a phase shift film having a transfer pattern formed on a light-transmitting substrate, as shown in Fig. 1. The phase shift film has a transmittance T P and a phase difference of 180 degrees Φ P The transfer pattern includes a hole portion consisting of a hole-shaped light-transmitting portion and a correction hole portion having a light-transmitting portion. The size (one side of a 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 with a representative wavelength of 334 nm. M and a phase difference of 85 degrees Φ P (In the comparative example, the repair hole portion is not dug.) The repair film has a thickness of 70 nm. In addition, optical simulations were performed on the repair hole portion with the repair film size (width dimension) of 1 μm, 1.5 μm, 2 μm, and 5 μm.

[0073] Fig. 5 is a diagram showing an aerial image of light intensity formed on a transfer target when using a phase shift mask of Comparative Example 1 of the present invention. Fig. 5 shows the results of an optical simulation of the hole portion and the correction hole portion of the phase shift film of Comparative Example 1. As shown in Figure 5, for the correction film formed in the correction hole, regardless of the size (width dimension), the absolute value of the peak light intensity was low relative to the hole profile ("Ref" in Figure 5), and there was a large variation in the slope forming the peak of the transmitted light intensity, both of which were outside the acceptable range.

[0074] From these results, it is predicted that even if the phase shift mask of Comparative Example 1 is set on the mask stage of an exposure tool and exposed and transferred to a resist film on a display device, the hole pattern that is ultimately formed on the display device cannot be formed with sufficient precision. [Explanation of symbols]

[0075] 1 Translucent substrate 1A Translucent part 1B Digged transparent part 2 Phase shift film 3A Hall Section 3B Correction hole section 4 Modified membrane 5. Light-shielding film 100,110 Phase shift mask

Claims

1. A phase shift mask comprising a phase shift film having a transfer pattern including a correction hole portion formed on a light-transmitting substrate, the correction hole portion includes a carved light-transmitting portion having a hole shape formed by carving a surface of the light-transmitting substrate, a correction film formed so as to surround an outer periphery of the carved light-transmitting portion, and a phase shift film formed so as to surround the correction film; The phase difference Φ between the exposure light transmitted through the phase shift film and the exposure light transmitted through air a distance equal to the thickness of the phase shift film. Ｐ is equal to or greater than 150 degrees and equal to or less than 210 degrees, The phase difference Φ between the exposure light transmitted through the correction film and the exposure light transmitted through air a distance equal to the thickness of the correction film Ｍ is the phase difference Φ Ｐ Smaller than A phase difference Φ generated between the exposure light transmitted through the correction film and the exposure light transmitted through the carved light transmitting portion Ｈ is equal to or greater than 150 degrees and equal to or less than 210 degrees, The transmittance T of the correction film for the exposure light Ｍ and the transmittance T of the phase shift film for the exposure light. Ｐ The phase shift mask according to claim 1, wherein the difference between the first and second phase shift masks is 2% or less.

2. The transmittance T of the phase shift film Ｐ 2. The phase shift mask according to claim 1, wherein the difference is 10% or more.

3. Transmittance T of the correction film Ｍ 2. The phase shift mask according to claim 1, wherein the difference is 10% or more.

4. The phase difference Φ between the exposure light transmitted through the correction film and the exposure light transmitted through air a distance equal to the thickness of the correction film Ｍ 2. The phase shift mask according to claim 1, wherein the angle is 100 degrees or less.

5. 2. The phase shift mask according to claim 1, wherein the exposure light includes at least light having a wavelength of 365 nm.

6. A method for manufacturing a phase shift mask having a phase shift film on a light-transmitting substrate, the method comprising the steps of: forming a transfer pattern including a hole portion formed of a hole-shaped light-transmitting portion in the phase shift film provided on the light-transmitting substrate; a step of performing a defect inspection on the transfer pattern of the phase shift film to identify a hole portion having a defect; Repairing the defect, The step of repairing the defect includes a step of forming a repair film for a hole portion in which the defect exists so as to surround an outer periphery of the light-transmitting portion, and a step of digging a surface of the light-transmitting substrate of the light-transmitting portion to form a dug-in light-transmitting portion, The phase difference Φ between the exposure light transmitted through the phase shift film and the exposure light transmitted through air a distance equal to the thickness of the phase shift film. Ｐ is equal to or greater than 150 degrees and equal to or less than 210 degrees, The phase difference Φ between the exposure light transmitted through the correction film and the exposure light transmitted through air a distance equal to the thickness of the correction film Ｍ is the phase difference Φ Ｐ Smaller than A phase difference Φ generated between the exposure light transmitted through the correction film and the exposure light transmitted through the carved light transmitting portion Ｈ is equal to or greater than 150 degrees and equal to or less than 210 degrees, The transmittance T of the correction film for the exposure light Ｍ and the transmittance T of the phase shift film for the exposure light. Ｐ and the difference between the first and second mask patterns is 2% or less.

7. The transmittance T of the phase shift film Ｐ 7. The method of claim 6, wherein the difference is 10% or more.

8. Transmittance T of the correction film Ｍ 7. The method of claim 6, wherein the difference is 10% or more.

9. 7. The method for producing a phase shift mask according to claim 6, wherein the exposure light includes at least light having a wavelength of 365 nm.

10. A step of placing the phase shift mask according to any one of claims 1 to 5 on a mask stage of an exposure tool; a step of irradiating the phase shift mask with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device; A method for manufacturing a display device comprising the steps of:

11. a step of placing a 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 tool; a step of irradiating the phase shift mask with exposure light to transfer a transfer pattern onto a resist film provided on a substrate for a display device; A method for manufacturing a display device comprising the steps of:

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