JP2021149092A - Photomask blank, photomask production method, and display device production method - Google Patents

Abstract

To provide a photomask blank capable of shortening over etching time when wet etching of a phase shift film, for suppressing damage to a substrate, and forming a transfer pattern having a preferable cross sectional shape and LER, and also having preferable chemical resistance.SOLUTION: A photomask blank is an original plate for forming a photomask, and the photomask has on a transparent substrate a phase shift film pattern which is acquired by wet etching of a phase shift film. The phase shift film is formed of a single layer or a multi layer. In the phase shift film, 50% or greater and 100% or smaller of a whole film thickness includes a MoZrSi based material layer formed of a material containing molybdenum, zirconium, silicon and nitrogen, the MoZrSi based material layer is configured so that an atom ratio of molybdenum and zirconium Mo:Zr is 1.5:1 to 1:4, and a content ratio of silicon to a total amount of molybdenum, zirconium, and silicon is 70-88 atom%.SELECTED DRAWING: Figure 1

Description

The present invention relates to a photomask blank, a method for manufacturing a photomask, and a method for manufacturing a display device.

In recent years, display devices such as FPDs (Flat Panel Display) represented by LCDs (Liquid Crystal Display) are rapidly increasing in definition and high speed as well as increasing the screen size and viewing angle. One of the elements necessary for high-definition and high-speed display is the production of electronic circuit patterns such as fine elements and wiring with high dimensional accuracy. Photolithography is often used for patterning electronic circuits for display devices. Therefore, a photomask such as a phase shift mask or a binary mask for manufacturing a display device in which a fine and highly accurate pattern is formed is required.

For example, Patent Document 1 discloses a phase inversion mask blank provided with a phase inversion film on a transparent substrate. In this mask blank, the phase inversion film has a transmittance of 35% or less and 1% to 40% with respect to exposure light having a compound wavelength including i-line (365 nm), h-line (405 nm), and g-line (436 nm). A metal silicide compound containing at least one light element substance of oxygen (O), nitrogen (N), and carbon (C) so as to have a transmittance and to form a sharp inclination of the pattern cross section at the time of pattern formation. The metal silicide compound is formed by injecting a reactive gas containing the above-mentioned light element substance and an inert gas at a ratio of 0.5: 9.5 to 4: 6, which is composed of two or more multilayer films composed of the above. ing.
Examples of the metal silicide compound include aluminum (Al), cobalt (Co), tungsten (W), molybdenum (Mo), vanadium (V), palladium (Pd), titanium (Ti), platinum (Pt), and manganese (Mn). ), Iron (Fe), Nickel (Ni), Cadmium (Cd), Zirconium (Zr), Magnesium (Mg), Lithium (Li), Selenium (Se), Copper (Cu), Ittrium (Y), Sulfur (S) ), Indium (In), Tin (Sn), Boron (B), Berylium (Be), Sodium (Na), Tantal (Ta), Hafnium (Hf), Niob (Nb) Is composed of silicon (Si), or one or more light elemental substances in nitrogen (N), oxygen (O), carbon (C), boron (B), and hydrogen (H) are added to the metal VDD. Materials are described that are characterized by further containing compounds.

Korean Registered Patent No. 1801101 Japanese Patent No. 3988041

The phase shift mask used for manufacturing high-definition (1000 ppi or more) panels in recent years is a phase shift mask having a hole diameter of 6 μm or less and a line in order to enable high-resolution pattern transfer. There is a demand for a phase shift mask in which a fine phase shift film pattern having a width of 4 μm or less is formed. Specifically, there is a demand for a phase shift mask in which a fine phase shift film pattern having a hole diameter of 1.5 μm is formed.
Further, in order to realize a higher resolution pattern transfer, a phase shift mask blank having a phase shift film having a transmittance of 15% or more for the exposure light and a phase shift film pattern having a transmittance of 15% or more for the exposure light are used. The formed phase shift mask is required.
In order to satisfy the requirement of transmittance for exposure light, it is effective to increase the ratio of silicon to the atomic ratio of metal to silicon in the metal silicide compound (metal silicide-based material) constituting the phase shift film, but wet etching is performed. There are problems that the speed becomes significantly slower (wet etching time becomes longer), damage to the substrate occurs due to the wet etching solution, and the permeability of the transparent substrate decreases.

Further, Patent Document 2 describes on a transparent substrate that molybdenum is used as a first metal component, one or more metals selected from tantalum, zirconium, chromium and tungsten are used as a second metal component, and oxygen, nitrogen and more. A halftone phase shift mask blank having a phase shifter film made of a metal VDD compound containing one or more elements selected from carbon is disclosed. Then, from the viewpoint of chemical resistance of the phase shifter film and processability at the time of etching, the ratio of the first metal component to the second metal component in the metal silicide compound is the first metal component: the second. It is disclosed that the metal component = 100: 1 to 2: 1 (atomic ratio) is preferable.
The phase shifter film disclosed in Patent Document 2 is intended to pattern the phase shifter film by dry etching when producing a phase shift mask, and the phase shifter film is wet-etched. In the case of patterning, there are problems that the wet etching rate of the phase shifter film is slow, damage to the substrate is generated by the wet etching solution, and the permeability of the transparent substrate is lowered, as described above.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object of the present invention is a transfer pattern possessed by a photomask even when the transmittance of the exposure light of the phase shift film with respect to a representative wavelength is high. In the formation of, the wet etching time of the phase shift film containing metal and silicon can be shortened to suppress damage to the substrate, and it has a good cross-sectional shape and line edge roughness (LER: Line Edge Roughness), and is resistant to chemicals. It is an object of the present invention to provide a photomask blank, a method for producing a photomask, and a method for producing a display device capable of forming a transfer pattern having good properties.

The present inventor has diligently studied measures for solving these problems. First, in order to obtain a phase shift film having a high transmittance with respect to a representative wavelength of exposure light (for example, 313 nm to 436 nm), attention was paid to zirconium having a characteristic that the extinction coefficient at the representative wavelength is smaller than that of molybdenum. As a material constituting the phase shift film, a MoZrSi-based material containing molybdenum, zirconium, silicon, and nitrogen was selected.

The use of a MoZrSi-based material as a phase shift film is known in mask blanks for LSIs used in the manufacture of semiconductor devices and the like. However, if the MoZrSi-based material used for the mask blank for LSI is applied to the phase shift mask blank for manufacturing the display device as it is, it takes too much time for wet etching the phase shift film, and the substrate is damaged. It was found that the occurrence of shavings and the decrease in transmittance of the transparent substrate could not be sufficiently suppressed. As described above, even if the MoZrSi-based material used for the mask blank for LSI is simply applied to the phase shift mask blank for manufacturing the display device, the desired phase shift mask blank for manufacturing the display device cannot be obtained. ..
It was also found that, depending on the composition ratio of the MoZrSi-based material, the chemical resistance of the phase shift film was poor and the desired cleaning resistance could not be obtained, and the reflectance was too high to deteriorate the transfer characteristics.
Therefore, it is effective for the present inventors to further study and define the atomic ratio of molybdenum and zirconium and the content ratio of silicon to the total of molybdenum, zirconium and silicon as indexes in the MoZrSi-based material. I found. That is, when the phase shift film is patterned by wet etching, the wet etching rate of the phase shift film is high, and when the phase shift film is patterned, damage to the transparent substrate due to the wet etching solution is suppressed. Therefore, it has been found as a result of diligent studies by the present inventor that the above problem can be solved by adjusting the atomic ratio of molybdenum and zirconium and the content ratio of silicon to the total of molybdenum, zirconium and silicon in the MoZrSi-based material. .. The present invention has been made as a result of the above diligent studies, and requires the following configuration.

(Structure 1) A photomask blank having a phase shift film on a transparent substrate.
The photomask blank is an original plate for forming a photomask, and the photomask is a photomask having a phase shift film pattern obtained by wet etching the phase shift film on the transparent substrate. ,
The phase shift film is composed of a single layer or multiple layers, and 50% or more and 100% or less of the total film thickness of the phase shift film is molybdenum (Mo), zirconium (Zr), silicon (Si), and nitrogen. Contains a MoZrSi-based material layer made of a material containing and
In the MoZrSi-based material layer, the atomic ratio of molybdenum and zirconium is Mo: Zr = 1.5: 1 to 1: 4 (1: 0.67 to 1: 4), and molybdenum, zirconium and silicon. A photomask blank characterized in that the content ratio of silicon to the total of molybdenum is 70 to 88 atomic%.

(Structure 2) The phase shift film is characterized by having a transmittance of 20% or more and 80% or less with respect to a representative wavelength of exposure light and having an optical characteristic of a phase difference of 160 ° or more and 200 ° or less. The photomask blank according to the configuration 1.

(Structure 3) The phase shift film is a laminated film including a lower layer on the transparent substrate side and an upper layer laminated on the lower layer, and the lower layer is the MoZrSi-based material layer. The photomask blank according to configuration 1 or 2.

(Structure 4) The photomask blank according to the configuration 3, wherein the upper layer is made of a material having a representative wavelength of exposure light, which is smaller than the refractive index of the lower layer and higher than the extinction coefficient.

(Structure 5) In the phase shift film, the refractive index, extinction coefficient, and film thickness of each of the upper layer and the lower layer are set so that the back surface reflectance with respect to the representative wavelength of the exposure light is 15% or less. The photomask blank according to the configuration 4, wherein the photomask blank is provided.

(Structure 6) The photomask blank according to any one of configurations 1 to 5, wherein an etching mask film having different etching selectivity with respect to the phase shift film is provided on the phase shift film.

(Structure 7) The step of preparing the photomask blank according to any one of configurations 1 to 5 and
A step of forming a resist film on the phase shift film, wet-etching the phase shift film using the resist film pattern formed from the resist film as a mask, and forming a phase shift film pattern on the transparent substrate. A method for producing a photo mask, which comprises.

(Structure 8) The step of preparing the photomask blank according to the configuration 6 and
A step of forming a resist film on the etching mask film, wet-etching the etching mask film using the resist film pattern formed from the resist film as a mask, and forming an etching mask film pattern on the phase shift film. ,
A method for producing a photomask, which comprises a step of wet-etching the phase shift film using the etching mask film pattern as a mask to form a phase shift film pattern on the transparent substrate.

(Structure 9) A transfer pattern including the phase shift film pattern formed on the photomask by placing the photomask obtained by the photomask manufacturing method according to the configuration 7 or 8 on a mask stage of an exposure apparatus. A method for manufacturing a display device, which comprises an exposure step of exposure transfer to a resist formed on a display device substrate.

According to the photomask blank according to the present invention, even when the transmittance of the exposure light of the phase shift film with respect to the representative wavelength is high, the phase containing the metal and silicon is formed in the formation of the transfer pattern of the photomask. It is possible to obtain a photomask blank capable of shortening the wet etching time of the shift film and forming a transfer pattern having good cross-sectional shape, line edge roughness, and chemical resistance.

Further, according to the method for producing a photomask according to the present invention, a photomask is produced using the above-mentioned photomask blank. Therefore, even when the transmittance of the exposure light of the phase shift film with respect to the representative wavelength is high, the wet etching rate of the phase shift film is high, and the transmittance of the transparent substrate caused by the damage to the transparent substrate by the wet etching solution. It is possible to manufacture a photomask having a transfer pattern (phase shift film pattern) having good transfer accuracy, line edge roughness, and chemical resistance. This photomask can be used for line-and-space patterns and miniaturization of contact holes.

Further, according to the method for manufacturing a display device according to the present invention, a display device is manufactured using the photomask obtained by the above method for manufacturing a photomask. Therefore, it is possible to manufacture a display device having a fine line-and-space pattern and contact holes.

It is a schematic diagram which shows the film structure (transparent substrate / phase shift film) of the phase shift mask blank which concerns on Embodiment 1. FIG. It is a schematic diagram which shows the film structure (transparent substrate / phase shift film / etching mask film) of the phase shift mask blank which concerns on Embodiment 2. It is a schematic diagram which shows the manufacturing process of the phase shift mask which concerns on Embodiment 3. It is a schematic diagram which shows the manufacturing process of the phase shift mask which concerns on Embodiment 4. FIG.

Embodiment 1.2.
In the first and second embodiments, a phase shift mask blank (photomask blank) will be described. The phase shift mask blank of the first embodiment is an original plate for forming a phase shift mask (photomask), and this phase shift mask masks an etching mask film pattern in which a desired pattern is formed on the etching mask film. This is a phase shift mask having a transfer pattern including a phase shift film pattern obtained by wet etching the phase shift film on a transparent substrate. Further, the phase shift mask blank of the second embodiment is an original plate for forming a phase shift mask, and this phase shift mask uses a resist film pattern in which a desired pattern is formed on the resist film as a mask to form a phase. It is a phase shift mask having a transfer pattern including a phase shift film pattern obtained by wet etching a shift film on a transparent substrate. The transfer pattern in the present specification is obtained by patterning at least one optical film formed on a transparent substrate. The above optical film may be a phase shift film or an etching mask film, and may further include other films (light-shielding film, reflection-suppressing film, conductive film, etc.). That is, the transfer pattern can include a patterned phase shift film or an etching mask film, and may further include other patterned films.

FIG. 1 is a schematic view showing a film configuration of the phase shift mask blank 10 according to the first embodiment.
The phase shift mask blank 10 shown in FIG. 1 includes a transparent substrate 20, a phase shift film 30 formed on the transparent substrate 20, and an etching mask film 40 formed on the phase shift film 30.
FIG. 2 is a schematic view showing the film configuration of the phase shift mask blank 10 according to the second embodiment.
The phase shift mask blank 10 shown in FIG. 2 includes a transparent substrate 20 and a phase shift film 30 formed on the transparent substrate 20.
Hereinafter, the transparent substrate 20, the phase shift film 30, and the etching mask film 40 constituting the phase shift mask blank 10 of the first and second embodiments will be described.

The transparent substrate 20 is transparent to the exposure light. The transparent substrate 20 has a transmittance of 85% or more, preferably 90% or more, with respect to the exposure light, assuming that there is no surface reflection loss. The transparent substrate 20 is made of a material containing silicon and oxygen, and is made of a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO _2- TiO ₂ glass, etc.). Can be done. When the transparent substrate 20 is made of low thermal expansion glass, it is possible to suppress a change in the position of the phase shift film pattern due to thermal deformation of the transparent substrate 20. The transparent substrate 20 used for display devices is generally a rectangular substrate, and the length of the short side of the transparent substrate is 300 mm or more. The phase shift mask blank 10 of the present invention has a fine size (for example, a width or a diameter of 2) formed on the transparent substrate 20 even if the length of the short side of the transparent substrate 20 is as large as 300 mm or more. A phase shift mask blank 10 capable of stably transferring a phase shift film pattern (less than .0 μm) and capable of providing a phase shift mask 100.

The phase shift film 30 is composed of a single layer or multiple layers, and 50% or more and 100% or less of the total film thickness of the phase shift film 30 is composed of molybdenum (Mo), zirconium (Zr), and silicon (Si). , It is composed of a MoZrSi-based material made of a material containing nitrogen. The MoZrSi-based material may further contain transition metals of tantalum (Ta), tungsten (W), and titanium (Ti).
Further, in the phase shift film 30, if the transmittance and the phase difference with respect to the representative wavelength of the exposure light are predetermined values, the portion of 50% or less with respect to the total film thickness of the phase shift film 30 is MoZrSi. It may be composed of a material other than the system material. In this case, a metal silicide-based material containing a metal and silicon that can be etched with the same wet etching solution as the MoZrSi-based material is preferable. For example, examples of metal silicide-based materials other than MoZrSi-based materials include molybdenum silicide-based materials (MoSi-based materials), zirconium silicide-based materials (ZrSi-based materials), tantalum silicide-based materials (TaSi-based materials), and tungsten silicide-based materials (WSi-based materials). Material), titanium silicide-based material (TiSi-based material), and examples. The MoSi-based material, ZrSi-based material, TaSi-based material, WSi-based material, and TiSi-based material may contain elements such as nitrogen, oxygen, and carbon.
In the MoZrSi-based material layer, the atomic ratio of molybdenum and zirconium is Mo: Zr = 1.5: 1 to 1: 4, that is, Mo: Zr = 1: 0.67 to 1: 4. In the case of the MoZrSi-based material layer in which the ratio of Zr is smaller than the range of the atomic ratio of Mo: Zr, the wet etching rate with respect to the wet etching solution becomes slow, so that damage to the transparent substrate is likely to occur. In addition, it becomes difficult to obtain a phase shift film having a high transmittance with respect to the representative wavelength of the exposure light. Further, in the case of the MoZrSi-based material layer in which the ratio of Zr is larger than the range of the atomic ratio of Mo: Zr, the phase shift has a high transmittance (for example, 20% or more and 80% or less) with respect to the representative wavelength of the exposure light. Although the film 30 can be easily obtained, the chemical resistance (cleaning resistance) is not sufficient, which is not preferable from the viewpoint of the quality of defects generated during film formation. The atomic ratio of molybdenum to zirconium is preferably Mo: Zr = 1: 0.8 to 1: 3, and more preferably Mo: Zr = 1: 1 to 1: 2.

Further, in the MoZrSi-based material layer, it is desirable that the content ratio of silicon (Si / [Mo + Zr + Si]) to the total of molybdenum, zirconium and silicon is Si / [Mo + Zr + Si] = 70 to 88 atomic%. When Si / [Mo + Zr + Si] is less than 70 atomic%, it becomes difficult to realize a phase shift film 30 having high transmittance (for example, 20% or more and 80% or less) and chemical resistance with respect to a representative wavelength of exposure light. Further, when Si / [Mo + Zr + Si] exceeds 88 atomic%, the wet etching rate with respect to the wet etching solution becomes slow, so that damage to the transparent substrate 20 is likely to occur, and the transmittance due to the roughness of the transparent substrate 20 is increased. The drop is likely to occur. The content ratio of silicon to the total of molybdenum, zirconium and silicon is preferably Si / [Mo + Zr + Si] = 72 to 86 atomic%, and more preferably Si / [Mo + Zr + Si] = 75 to 85 atomic%.
The phase shift film 30 can be formed by a sputtering method.
In the MoZrSi-based material layer of the phase shift film 30 in the present embodiment, the atomic ratio of molybdenum and zirconium and the content ratio of silicon to the total of molybdenum, zirconium and silicon satisfy the above-mentioned range. A phase shift film capable of forming a film with a good degree of vacuum within 5 Pa, shortening the overetching time, suppressing damage to the transparent substrate 20, having a good cross-sectional shape and LER, and having good chemical resistance. The pattern 30a can be formed.

The phase shift film 30 may have a columnar structure. This columnar structure can be confirmed by observing the phase shift film 30 in cross section by SEM. That is, in the columnar structure in the present invention, the particles of the transition metal silicide compound containing molybdenum, zirconium, and silicon constituting the phase shift film 30 are oriented in the film thickness direction of the phase shift film 30 (the direction in which the particles are deposited). A state having a columnar particle structure extending toward it. The phase shift film 30 having this columnar structure is preferable in that a high transmittance can be easily obtained.

Further, in addition to the above-mentioned nitrogen, the phase shift film 30 may contain oxygen for the purpose of adjusting the transmittance, and further, for the purpose of reducing the film stress and controlling the wet etching rate, helium or the like may be contained. It may contain other elements such as carbon.

The transmittance of the phase shift film 30 with respect to the exposure light satisfies the value required for the phase shift film 30. The transmittance of the phase shift film 30 is preferably 20% or more and 80% or less, and more preferably 25% or more and 75% or less with respect to the light of a predetermined wavelength (representative wavelength) contained in the exposure light. Yes, more preferably 30% or more and 70% or less. That is, when the exposure light is composite light containing light in a wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-mentioned transmittance with respect to light of a representative wavelength included in the wavelength range. For example, when the exposure light is a composite light containing i-line, h-line and g-line, the phase shift film 30 has the above-mentioned transmittance for any of i-line, h-line and g-line.
The transmittance can be measured using a phase shift amount measuring device or the like.

The phase difference of the phase shift film 30 with respect to the exposure light satisfies the value required for the phase shift film 30. The phase difference of the phase shift film 30 is preferably 160 ° or more and 200 ° or less, and more preferably 170 ° or more and 190 ° or less with respect to the light of the representative wavelength contained in the exposure light. Due to this property, the phase of the light of the representative wavelength contained in the exposure light can be changed (shifted) to 160 ° or more and 200 ° or less. Therefore, a phase difference of 160 ° or more and 200 ° or less occurs between the light of the representative wavelength transmitted through the phase shift film 30 and the light of the representative wavelength transmitted only through the transparent substrate 20. That is, when the exposure light is composite light containing light in a wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-mentioned phase difference with respect to light having a representative wavelength included in the wavelength range. For example, when the exposure light is a composite light including i-line, h-line, and g-line, the phase shift film 30 has the above-mentioned phase difference with respect to any of i-line, h-line, and g-line.
The phase difference can be measured using a phase shift amount measuring device or the like.

Further, the phase shift film 30 may be a laminated film including a lower layer on the transparent substrate side and an upper layer laminated on the lower layer. When the phase shift film 30 is a laminated film including a lower layer and an upper layer, the defect quality of the phase shift film 30, suppression of damage to the transparent substrate 20 by the wet etching solution, and a pattern when the phase shift film 30 is patterned by wet etching. From the viewpoint of improving the cross-sectional shape, it is preferable that the lower layer is the MoZrSi-based material layer. The upper layer of the phase shift film 30 may be the same MoZrSi-based material layer as the lower layer, or may be different. When the upper layer is different from the material of the lower layer, a metal silicide-based material that can be etched with the same wet etching solution as the MoZrSi-based material, for example, a MoSi-based material, a ZrSi-based material, a TaSi-based material, a WSi-based material, or a TiSi-based material is used. can do.

Further, for the phase shift film 30, a material whose upper layer is smaller than the refractive index n at the representative wavelength of the exposure light in the lower layer (for example, 313 nm to 436 nm) and higher than the extinction coefficient k is selected. Thereby, the back surface reflectance of the phase shift film 30 on the side where the exposure light is incident can be reduced.
Specifically, the refractive index, extinction coefficient, and film thickness of the upper layer and the lower layer may be set so that the back surface reflectance with respect to the representative wavelength of the exposure light is 15% or less. Preferably, it is desirable that the back surface reflectance of the phase shift film 30 with respect to the representative wavelength of the exposure light is 10% or less.

The etching mask film 40 is made of a material that is arranged above the phase shift film 30 and has etching resistance to an etching solution that etches the phase shift film 30 (etching selectivity is different from that of the phase shift film 30). Further, the etching mask film 40 may have a function of blocking the transmission of exposure light, and the film surface reflectance of the phase shift film 30 with respect to the light incident from the phase shift film 30 side is in the wavelength range of 313 nm to 436 nm. It may have a function of reducing the film surface reflectance so as to be 15% or less. The etching mask film 40 is made of a chromium-based material containing chromium (Cr). More specifically, as a chromium-based material, a material containing chromium (Cr) or chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C). Can be mentioned. Alternatively, a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C), and further containing fluorine (F) can be mentioned. For example, examples of the material constituting the etching mask film 40 include Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF.
The etching mask film 40 can be formed by a sputtering method.

When the etching mask film 40 has a function of blocking the transmission of the exposure light, the optical density with respect to the exposure light is preferably 3 or more, more preferably, in the portion where the phase shift film 30 and the etching mask film 40 are laminated. It is 3.5 or more, more preferably 4 or more.
The optical density can be measured using a spectrophotometer, an OD meter, or the like.

The etching mask film 40 may be composed of a single film having a uniform composition depending on the function, may be composed of a plurality of films having different compositions, or may have a composition in the thickness direction. It may consist of a single membrane that changes continuously.

The phase shift mask blank 10 shown in FIG. 1 has an etching mask film 40 on the phase shift film 30, but has an etching mask film 40 on the phase shift film 30 and a resist film on the etching mask film 40. The present invention can also be applied to a phase shift mask blank provided with.

Next, a method of manufacturing the phase shift mask blank 10 of the first and second embodiments will be described. The phase shift mask blank 10 shown in FIG. 1 is manufactured by performing the following phase shift film forming step and etching mask film forming step. The phase shift mask blank 10 shown in FIG. 2 is manufactured by a phase shift film forming step.
Hereinafter, each step will be described in detail.

1. 1. Phase shift film forming step First, the transparent substrate 20 is prepared. The transparent substrate 20 is made of any glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO _2- TiO _{2 glass, etc.) as long as it is transparent to the exposure light.} It may be what is done.

Next, the phase shift film 30 is formed on the transparent substrate 20 by a sputtering method.
The phase shift film 30 is formed by a MoZrSi-based target containing molybdenum (Mo), zirconium (Zr) and silicon (Si), which are the main components of the material constituting the phase shift film 30, or molybdenum (Mo) and zirconium (Mo) and zirconium (Si). Using MoZrSiO-based targets, MoZrSiN-based targets, and MoZrSiON-based targets containing Zr), silicon (Si), oxygen (O) and / or nitrogen (N) as sputter targets, for example, helium gas, neon gas, argon gas, etc. A sputter gas atmosphere consisting of an inert gas containing at least one selected from the group consisting of krypton gas and xenon gas, or the above-mentioned inert gas and oxygen gas, nitrogen gas, carbon dioxide gas, nitrogen monoxide gas, nitrogen dioxide gas. It is carried out in a sputter gas atmosphere composed of a mixed gas with an active gas containing at least nitrogen selected from the group consisting of. For Mo, Zr, and Si in the MoZrSi-based target, MoZrSiO-based target, MoZrSiN-based target, and MoZrSiON-based target, the atomic ratio of molybdenum and zirconium in the MoZrSi-based material layer formed by sputtering is Mo: Zr = 1.5. : 1 to 1: 4 (1: 0.67 to 1: 4), and the content ratio of silicon to the total of molybdenum, zirconium, and silicon is adjusted to be 70 to 88 atomic%. Further, the phase shift film 30 may be formed by using a Mo target, a Zr target, and a Si target so as to satisfy the above-mentioned atomic ratios and content ratios of Mo, Zr, and Si, or may be formed with the MoSi target. The film may be formed using a ZrSi target.

The composition and thickness of the phase shift film 30 are adjusted so that the phase shift film 30 has the above-mentioned phase difference and transmittance. The composition of the phase shift film 30 can be controlled by the content ratio of the elements constituting the sputtering target (for example, the content of Mo, Zr, Si), the composition of the sputtering gas, the flow rate, and the like. The thickness of the phase shift film 30 can be controlled by the sputtering power, the sputtering time, or the like. Further, the phase shift film 30 is preferably formed by using an in-line sputtering apparatus. When the sputtering apparatus is an in-line type sputtering apparatus, the thickness of the phase shift film 30 can also be controlled by the transport speed of the transparent substrate 20.

When the phase shift film 30 is composed of a single film, the above-mentioned film forming process is performed only once while changing the composition and flow rate of the sputter gas with the elapsed time of the film forming process. When the phase shift film 30 is composed of a plurality of films having different compositions, the above-mentioned film forming process is performed a plurality of times by changing the composition and flow rate of the sputtering gas for each film forming process. The phase shift film 30 may be formed by using targets having different content ratios of elements constituting the sputtering target. When the film forming process is performed a plurality of times, the sputtering power applied to the sputtering target can be reduced.
In this way, the phase shift mask blank 10 of the second embodiment is obtained. In the production of the phase shift mask blank 10 of the first embodiment, the following etching mask film forming step is further performed.

3. 3. Etching Mask Film Forming Step After performing a surface treatment for adjusting the surface oxidation state of the surface of the phase shift film 30 as necessary, the etching mask film 40 is formed on the phase shift film 30 by a sputtering method. The etching mask film 40 is preferably formed using an in-line sputtering apparatus. When the sputtering apparatus is an in-line type sputtering apparatus, the thickness of the etching mask film 40 can also be controlled by the transport speed of the transparent substrate 20.
The etching mask film 40 is formed by using a sputter target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxide nitride, chromium oxide nitride, etc.), for example, helium gas, neon gas, argon. A sputter gas atmosphere consisting of an inert gas containing at least one selected from the group consisting of gas, krypton gas and xenone gas, or at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas and xenone gas. From a mixed gas of an inert gas containing at least one selected from the group consisting of oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas, and fluorine gas. It is performed in a spatter gas atmosphere. Examples of the hydrocarbon gas include methane gas, butane gas, propane gas, styrene gas and the like.

When the etching mask film 40 is composed of a single film having a uniform composition, the above-mentioned film forming process is performed only once without changing the composition and flow rate of the sputtering gas. When the etching mask film 40 is composed of a plurality of films having different compositions, the above-mentioned film forming process is performed a plurality of times by changing the composition and flow rate of the sputter gas for each film forming process. When the etching mask film 40 is composed of a single film whose composition continuously changes in the thickness direction, the above-mentioned film forming process is performed while changing the composition and flow rate of the sputtering gas with the elapsed time of the film forming process. Do it only once.
In this way, the phase shift mask blank 10 of the first embodiment is obtained.

Since the phase shift mask blank 10 shown in FIG. 1 includes the etching mask film 40 on the phase shift film 30, an etching mask film forming step is performed when the phase shift mask blank 10 is manufactured. Further, when manufacturing a phase shift mask blank having an etching mask film 40 on the phase shift film 30 and a resist film on the etching mask film 40, a resist film is formed on the etching mask film 40 after the etching mask film forming step. To form. Further, in the phase shift mask blank 10 shown in FIG. 2, when manufacturing a phase shift mask blank having a resist film on the phase shift film 30, a resist film is formed after the phase shift film forming step.

The phase shift mask blanks 10 of the first and second embodiments have a good cross-sectional shape by wet etching, and a phase shift film pattern 30a having high transmittance can be formed in a short etching time. Therefore, a phase shift mask 100 capable of accurately transferring a high-definition phase shift film pattern 30a without a decrease in the transmittance of the transparent substrate 20 due to damage to the transparent substrate 20 by the wet etching solution is manufactured. A phase shift mask blank 10 that can be obtained is obtained.

Embodiment 3.4.
In the third and fourth embodiments, a method of manufacturing the phase shift mask 100 will be described.

FIG. 3 is a schematic view showing a method of manufacturing the phase shift mask 100 according to the third embodiment. FIG. 4 is a schematic view showing a method of manufacturing the phase shift mask 100 according to the fourth embodiment.
The method for manufacturing the phase shift mask 100 shown in FIG. 3 is a method for manufacturing the phase shift mask 100 using the phase shift mask blank 10 shown in FIG. 1, and is formed on the etching mask film 40 of the following phase shift mask blank 10. A resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film and a step of forming the resist film (first resist film pattern forming step), and the resist film pattern 50 is used as a mask. A step of wet-etching the etching mask film 40 to form an etching mask film pattern 40a on the phase shift film 30 (first etching mask film pattern forming step) and a phase using the etching mask film pattern 40a as a mask. The process includes a step of wet-etching the shift film 30 to form a phase shift film pattern 30a on the transparent substrate 20 (phase shift film pattern forming step). Then, a second resist film pattern forming step and a second etching mask film pattern forming step are further included.

The method for manufacturing the phase shift mask 100 shown in FIG. 4 is a method for manufacturing the phase shift mask 100 using the phase shift mask blank 10 shown in FIG. 2, and a resist film is formed on the following phase shift mask blank 10. A resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film (first resist film pattern forming step), and the phase shift film 30 is masked by the resist film pattern 50. Is wet-etched to form a phase shift film pattern 30a on the transparent substrate 20 (phase shift film pattern forming step).
Hereinafter, each step of the manufacturing process of the phase shift mask 100 according to the third and fourth embodiments will be described in detail.

1. Manufacturing process of the phase shift mask 100 according to the third embodiment. First Resist Film Pattern Forming Step In the first resist film pattern forming step, first, a resist film is formed on the etching mask film 40 of the phase shift mask blank 10 of the first embodiment. The resist film material used is not particularly limited. For example, it may be sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Further, the resist film may be either a positive type or a negative type.
Then, a desired pattern is drawn on the resist film using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is a pattern formed on the phase shift film 30. Examples of the pattern drawn on the resist film include a line-and-space pattern and a hole pattern.
Then, the resist film is developed with a predetermined developer to form a first resist film pattern 50 on the etching mask film 40 as shown in FIG. 3 (a).

2. First Etching Mask Film Pattern Forming Step In the first etching mask film pattern forming step, first, the etching mask film 40 is etched using the first resist film pattern 50 as a mask, and the first etching mask film pattern 40a To form. The etching mask film 40 is formed of a chromium-based material containing chromium (Cr). The etching solution for etching the etching mask film 40 is not particularly limited as long as it can selectively etch the etching mask film 40. Specific examples thereof include an etching solution containing di-cerium ammonium nitrate and perchloric acid.
Then, as shown in FIG. 3B, the first resist film pattern 50 is peeled off using a resist stripping solution or by ashing. In some cases, the next phase shift film pattern forming step may be performed without peeling off the first resist film pattern 50.

3. 3. Phase shift film pattern forming step In the first phase shift film pattern forming step, the phase shift film 30 is wet-etched using the first etching mask film pattern 40a as a mask, and as shown in FIG. 3C, The phase shift film pattern 30a is formed. Examples of the phase shift film pattern 30a include a line-and-space pattern and a hole pattern. The etching solution for etching the phase shift film 30 is not particularly limited as long as it can selectively etch the phase shift film 30. For example, an etching solution containing ammonium fluoride, phosphoric acid and hydrogen peroxide, and an etching solution containing ammonium hydrogen fluoride and hydrogen peroxide can be mentioned.
Wet etching is performed in a time (over etching time) longer than the time until the transparent substrate 20 is exposed in the phase shift film pattern 30a (just etching time) in order to improve the cross-sectional shape of the phase shift film pattern 30a. Is preferable. The over-etching time is preferably set to be within a time obtained by adding 10 to 20% of the just etching time to the just etching time in consideration of the influence on the transparent substrate 20 and the like.

4. Second resist film pattern forming step In the second resist film pattern forming step, first, a resist film covering the first etching mask film pattern 40a is formed. The resist film material used is not particularly limited. For example, it may be sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Further, the resist film may be either a positive type or a negative type.
Then, a desired pattern is drawn on the resist film using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is a light-shielding band pattern that blocks the outer peripheral region of the region where the phase-shift film pattern 30a is formed, a light-shielding band pattern that blocks the central portion of the phase-shift film pattern 30a, and the like. The pattern drawn on the resist film may not have a light-shielding band pattern that shields the central portion of the phase-shift film pattern 30a from light depending on the transmittance of the phase-shift film 30 with respect to the exposure light.
Then, the resist film is developed with a predetermined developer to form a second resist film pattern 60 on the first etching mask film pattern 40a as shown in FIG. 3 (d).

5. Second Etching Mask Film Pattern Forming Step In the second etching mask film pattern forming step, the first etching mask film pattern 40a is etched with the second resist film pattern 60 as a mask, and FIG. 3 (e) shows. As shown, a second etching mask film pattern 40b is formed. The first etching mask film pattern 40a is formed from a chromium-based material containing chromium (Cr). The etching solution for etching the first etching mask film pattern 40a is not particularly limited as long as it can selectively etch the first etching mask film pattern 40a. For example, an etching solution containing di-cerium ammonium nitrate and perchloric acid can be mentioned.
Then, the second resist film pattern 60 is peeled off using a resist stripping solution or by ashing.
In this way, the phase shift mask 100 is obtained. That is, the transfer pattern included in the phase shift mask 100 according to the third embodiment can include the phase shift film pattern 30a and the second etching mask film pattern 40b.
In the above description, the case where the etching mask film 40 has a function of blocking the transmission of exposure light has been described, but the case where the etching mask film 40 has only the function of a hard mask when etching the phase shift film 30. In the above description, the second resist film pattern forming step and the second etching mask film pattern forming step are not performed, and after the phase shift film pattern forming step, the first etching mask film pattern is peeled off. , The phase shift mask 100 is manufactured. That is, the transfer pattern of the phase shift mask 100 according to the third embodiment may be composed of only the phase shift film pattern 30a. The transfer pattern may further include other membrane patterns. Examples of other films include a film that suppresses reflection and a conductive film.

According to the method for manufacturing the phase shift mask 100 of the third embodiment, since the phase shift mask blank 10 of the first embodiment is used, the transparent substrate 20 is permeated due to the damage to the transparent substrate 20 by the wet etching solution. There is no decrease in the rate, the etching time can be shortened, and the phase shift film pattern 30a having good cross-sectional shape, line edge roughness, and chemical resistance can be formed. Therefore, it is possible to manufacture the phase shift mask 100 capable of accurately transferring the high-definition phase shift film pattern 30a. The phase shift mask 100 manufactured in this way can cope with the miniaturization of line-and-space patterns and contact holes.

1. Manufacturing process of the phase shift mask 100 according to the fourth embodiment. Resist film pattern forming step In the resist film pattern forming step, first, a resist film is formed on the phase shift film 30 of the phase shift mask blank 10 of the second embodiment. The resist film material used is the same as described in the third embodiment. If necessary, the phase shift film 30 may be subjected to a surface modification treatment in order to improve the adhesion with the phase shift film 30 before forming the resist film. Similar to the above, after forming the resist film, a desired pattern is drawn on the resist film using laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm. Then, the resist film is developed with a predetermined developer to form a resist film pattern 50 on the phase shift film 30 as shown in FIG. 4 (a).
2. Phase shift film pattern forming step In the phase shift film pattern forming step, the phase shift film 30 is etched by using the resist film pattern as a mask to form the phase shift film pattern 30a as shown in FIG. 4 (b). As a result, a transfer pattern is formed. The etching solution for etching the phase shift film pattern 30a and the phase shift film 30 and the overetching time are the same as those described in the third embodiment.
Then, the resist film pattern 50 is peeled off using a resist stripping solution or by ashing (FIG. 4 (c)).
In this way, the phase shift mask 100 is obtained. The transfer pattern of the phase shift mask according to the present embodiment is composed of only the phase shift film pattern 30a, but may further include other film patterns. Examples of other films include a film that suppresses reflection and a conductive film.
According to the method for manufacturing the phase shift mask 100 of the fourth embodiment, since the phase shift mask blank 10 of the second embodiment is used, the transparent substrate 20 is permeated due to the damage to the transparent substrate 20 by the wet etching solution. There is no decrease in the rate, the etching time can be shortened, and a phase shift film pattern 30a having good cross-sectional shape, line edge roughness, and chemical resistance can be formed. Therefore, it is possible to manufacture the phase shift mask 100 capable of accurately transferring the high-definition phase shift film pattern 30a. The phase shift mask 100 manufactured in this way can cope with the miniaturization of line-and-space patterns and contact holes.

Embodiment 5.
In the fifth embodiment, a method of manufacturing the display device will be described. The display device uses a phase shift mask 100 manufactured by using the phase shift mask blank 10 described above, or a step of using the phase shift mask 100 manufactured by the method of manufacturing the phase shift mask 100 described above (mask mounting step). ) And a step of exposing and transferring a transfer pattern including the phase shift film pattern 30a to the resist film on the substrate for the display device (exposure step).
Hereinafter, each step will be described in detail.

1. 1. Mounting step In the mounting step, the phase shift mask 100 manufactured in the third or fourth embodiment is mounted on the mask stage of the exposure apparatus. Here, the phase shift mask 100 is arranged so as to face the resist film formed on the display device substrate via the projection optical system of the exposure device.

2. Pattern transfer step In the pattern transfer step, the phase shift mask 100 is irradiated with exposure light to transfer the transfer pattern including the phase shift film pattern 30a to the resist film formed on the substrate for the display device. The exposure light is a composite light containing light having a plurality of wavelengths selected from the wavelength range of 365 nm to 436 nm, or monochromatic light selected by cutting a certain wavelength range from the wavelength range of 365 nm to 436 nm with a filter or the like. For example, the exposure light is a composite light containing at least one of i-line, h-line, and g-line, or i-line monochromatic light. When composite light is used as the exposure light, the exposure light intensity can be increased and the throughput can be increased, so that the manufacturing cost of the display device can be reduced.

According to the method of manufacturing the display device of the fifth embodiment, it is possible to manufacture a high-definition display device having a high resolution, a fine line-and-space pattern, and a contact hole.

Example 1. A. Phase shift mask blank In order to manufacture the phase shift mask blank 10 of Example 1, first, a synthetic quartz glass substrate of 1214 size (1220 mm × 1400 mm) was prepared as the transparent substrate 20.

Then, the synthetic quartz glass substrate was mounted on a tray (not shown) with one main surface facing downward, and carried into the chamber of the in-line sputtering apparatus.
In order to form the phase shift film 30 on the other main surface of the transparent substrate 20, first, argon (Ar) gas and nitrogen (N ₂ ) gas are placed in the first chamber in a state where the sputtering gas pressure is 0.5 Pa. A mixed gas composed of and was introduced. Then, using a MoZrSi target in which the atomic ratio of Mo, Zr, and Si is Mo: Zr: Si = 10: 10: 80, molybdenum, zirconium, and silicon are placed on the main surface of the transparent substrate 20 by reactive sputtering. A MoZrSiN-based phase shift film 30 containing and nitrogen was formed with a film thickness of 143 nm. The atomic ratio in the target for sputtering is an example, and can be appropriately selected according to the desired composition of the phase shift film 30.

Next, the transparent substrate 20 with the phase shift film 30 is carried into the second chamber, _{and a mixed gas of argon (Ar) gas and nitrogen (N 2} ) gas is introduced into the second chamber by reactive sputtering. , Chromium nitride (CrN) containing chromium and nitrogen was formed on the phase shift film 30 (thickness: 15 nm). Next, with the inside of the third chamber kept at a predetermined degree of vacuum, a mixed gas of argon (Ar) gas and methane gas is introduced, and chromium carbide (CrC) containing chromium and carbon is formed on CrN by reactive sputtering. Formed (thickness 60 nm). Finally, a mixed gas of argon (Ar) gas and methane gas and a mixed gas of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas is introduced into the fourth chamber in a state of having a predetermined degree of vacuum, and the reaction is carried out. Chromium carbide nitride (CrCON) containing chromium, carbon, oxygen and nitrogen was formed on CrC by sex sputtering (thickness: 30 nm). As described above, the etching mask film 40 having a laminated structure of the CrN layer, the CrC layer, and the CrCON layer was formed on the phase shift film 30.
In this way, a phase shift mask blank 10 in which the phase shift film 30 and the etching mask film 40 were formed on the transparent substrate 20 was obtained.

With respect to the refractive index and extinction coefficient of the phase shift film 30 of the obtained phase shift mask blank 10, the phase shift film 30 is formed on the main surface of a synthetic quartz glass substrate prepared by setting them on the same tray. The measurement was performed using a substrate with a phase shift film (dummy substrate).
As a result, the refractive index n of the MoZrSiN-based phase shift film was 2.45 (wavelength 405 nm), and the extinction coefficient k was 0.11 (wavelength 405 nm).
Further, the transmittance and the phase difference of the surface of the phase shift film 30 of the obtained phase shift mask blank 10 were measured by MPM-100 manufactured by Lasertec. The transmittance and phase difference of the phase shift film 30 are measured by setting the phase shift film 30 on the main surface of a synthetic quartz glass substrate, which is produced by setting the same tray in the same manner as described above. A substrate with a film (dummy substrate) was used. The transmittance and phase difference of the phase shift film 30 were measured by taking out a substrate with a phase shift film (dummy substrate) from the chamber before forming the etching mask film 40. As a result, the transmittance is 50% (wavelength: 405 nm), the phase difference is 180 ° (wavelength: 405 nm), the back surface reflectance is 15.4% (wavelength: 405 nm), and the surface reflectance is 21.3% (wavelength 405 nm). )Met.

Further, the phase shift film 30 of the obtained phase shift mask blank 10 was subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS).
In the composition analysis result in the depth direction by XPS for the phase shift mask blank 10, the phase shift film 30 includes a composition gradient region at the interface between the transparent substrate 20 and the phase shift film 30, and the phase shift film 30 and the etching mask film 40. Except for the composition gradient region of the interface with, the content of each constituent element is almost constant in the depth direction, Mo is 3 atomic%, Zr is 5 atomic%, Si is 42 atomic%, and N is. It was 47 atomic% and O was 3 atomic%. The atomic ratio of molybdenum and zirconium was 1: 1 and was in the range of Mo: Zr = 1: 0.67 to 1: 4. The content ratio of silicon to the total of molybdenum, zirconium and silicon was 84 atomic%, which was in the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic%. It is considered that the reason why the phase shift film 30 contains oxygen is that a small amount of oxygen was present in the chamber at the time of film formation.

B. Phase shift mask and its manufacturing method In order to manufacture the phase shift mask 100 using the phase shift mask blank 10 manufactured as described above, first, a resist coating apparatus is applied on the etching mask film 40 of the phase shift mask blank 10. A photoresist film was applied using.
Then, through the heating and cooling steps, a photoresist film having a film thickness of 520 nm was formed.
Then, a photoresist film was drawn using a laser drawing apparatus, and a resist film pattern having a hole pattern having a hole diameter of 1.5 μm was formed on the etching mask film through development and rinsing steps.

Then, using the resist film pattern as a mask, the etching mask film was wet-etched with a chromium etching solution containing dicerium ammonium nitrate and perchloric acid to form the first etching mask film pattern 40a.

Then, using the first etching mask film pattern 40a as a mask, the phase shift film 30 is wet-etched with a molybdenum VDD etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water to shift the phase. A film pattern 30a was formed. This wet etching was performed with an overetching time of 10% in order to verticalize the cross-sectional shape and to form the required fine pattern.
Then, the resist film pattern was peeled off.

Then, using a resist coating apparatus, a photoresist film was applied so as to cover the first etching mask film pattern 40a.
Then, through the heating and cooling steps, a photoresist film having a film thickness of 520 nm was formed.
Then, a photoresist film was drawn using a laser drawing apparatus, and a second resist film pattern 60 for forming a light-shielding band was formed on the first etching mask film pattern 40a through a developing and rinsing step. ..

Then, using the second resist film pattern 60 as a mask, the first etching mask film pattern 40a formed in the transfer pattern forming region is wet-etched with a chromium etching solution containing dicerium nitrate ammonium nitrate and perchloric acid. bottom.
Then, the second resist film pattern 60 was peeled off.

In this way, a light-shielding band formed of a laminated structure of the phase shift film pattern 30a having a hole diameter of 1.5 μm, the phase shift film pattern 30a, and the etching mask film pattern 40b is formed in the transfer pattern forming region on the transparent substrate 20. The obtained phase shift mask 100 was obtained.

The cross section of the obtained phase shift mask was observed with a scanning electron microscope. In the cross-sectional view, the angle formed by the edge of the phase shift film pattern 30a of the phase shift mask and the main surface of the transparent substrate 20 was 76 °, and the phase shift film pattern 30a had a cross-sectional shape close to vertical. Further, when the phase shift film pattern 30a was observed from above and the LER of the phase shift film pattern 30a was observed, the edges of the phase shift film pattern (hole pattern) 30a were smooth and substantially linear, which was good. Met. That is, no conspicuous uneven shape was confirmed at the edge of the phase shift film pattern 30a viewed from above. The phase shift film pattern 30a formed on the phase shift mask of Example 1 had a cross-sectional shape capable of sufficiently exerting the phase shift effect. Further, the surface of the exposed transparent substrate 20 after the phase shift film 30 was removed was smooth, and the decrease in transmittance due to the surface roughness of the transparent substrate 20 was negligible. Moreover, when the obtained phase shift mask 100 was observed by electron diffraction, it was confirmed that it had an amorphous structure. Further, no penetration of the etching solution or the like was observed at either the interface of the phase shift film pattern 30a with the etching mask film pattern 40b and the interface with the transparent substrate 20, and the chemical resistance was also good. .. Therefore, it has an excellent phase shift effect in the exposure light containing light in the wavelength range of 313 nm or more and 500 nm or less, more specifically, in the exposure light of composite light containing at least one i-line, h-line and g-line. The phase shift mask 100 was obtained.
Therefore, when the phase shift mask 100 of Example 1 is set on the mask stage of the exposure apparatus and the exposure transfer is performed on the resist film on the substrate for the display device, a fine pattern of less than 2.0 μm can be transferred with high accuracy. It can be said that it can be done. Further, since the phase shift film 30 (phase shift film pattern 30a) is a dense film formed in a state where the degree of vacuum is as low as 0.5 Pa or less, the light resistance in the exposure light is also good. Can be expected.

Examples 2-4.
A. In Examples 2 to 4, the phase shift mask blank 10 and the phase shift mask 100 were manufactured by the same structure and method as in Example 1 except for the phase shift film 30. In Examples 2 to 4, the atomic ratios of Mo, Zr, and Si of the sputtering target when forming the phase shift film 30 in Example 1 described above were appropriately adjusted. The film thickness of the phase shift film 30 was appropriately adjusted so that the transmittance at a wavelength of 405 nm was 20% or more and 80% or less and the phase difference was in the range of 160 ° to 200 °.
As a result of analyzing the composition of the obtained MoZrSiN-based phase shift film 30 in the same manner as in Example 1, the atomic ratios of Mo and Zr were as follows.
Example 2 Mo: Zr = 1.5: 1 (1: 0.67),
Example 3 Mo: Zr = 1: 2,
Example 4 Mo: Zr = 1: 4,

As described above, in all of Examples 2 to 4, it was within the range of Mo: Zr = 1: 0.67 to 1: 4. Further, the content ratio of silicon to the total of molybdenum, zirconium and silicon was in the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic% in any of Examples 2 to 4.

B. Phase shift mask and its manufacturing method In the same manner as in Example 1 described above, the phase shift mask 100 is produced, and the cross-sectional shape of the phase shift film pattern 30a and the exposed transparent substrate 20 after the phase shift film 30 is removed. The surface condition was confirmed. As a result, in any of Examples 2 to 4, the angle formed by the edge of the phase shift film pattern 30a of the phase shift mask 100 and the main surface of the transparent substrate 20 when viewed in cross section exceeds 70 °. The phase shift film pattern 30a of No. 1 also had a cross-sectional shape close to vertical. Further, when the LER of these phase shift film patterns 30a was observed in the same manner as in Example 1, the edges of the phase shift film pattern (hole pattern) 30a were smooth and substantially linear in all of Examples 2 to 4. It was a good one. That is, no conspicuous uneven shape was confirmed at the edge of the phase shift film pattern 30a viewed from above. The phase shift film pattern 30a formed on the phase shift masks of Examples 2 to 4 had a cross-sectional shape capable of sufficiently exerting the phase shift effect. Further, in all of Examples 2 to 4, the surface of the exposed transparent substrate 20 after the phase shift film 30 was removed was smooth, and the decrease in transmittance due to the surface roughness of the transparent substrate 20 was negligible. Moreover, when the obtained phase shift mask 100 was observed by electron diffraction, it was confirmed that all of Examples 2 to 4 had an amorphous structure. Further, in any of Examples 2 to 4, penetration of the etching solution or the like was observed at both the interface of the phase shift film pattern 30a with the etching mask film pattern 40b and the interface with the transparent substrate 20. However, the chemical resistance was also good. Therefore, in any of Examples 2 to 4, the exposure light containing light in the wavelength range of 313 nm or more and 500 nm or less, more specifically, the composite light containing at least one of i-line, h-line and g-line. A phase shift mask 100 having an excellent phase shift effect in the exposure light was obtained.
Therefore, when the phase shift mask 100 of Examples 2 to 4 is set on the mask stage of the exposure apparatus and exposed to the resist film on the substrate for the display device, a fine pattern of less than 2.0 μm is transferred with high accuracy. It can be said that it can be done. Further, the phase shift film 30 (phase shift film pattern 30a) is formed into a dense film in a state where the degree of vacuum is as low as 0.5 Pa or less, so that the light resistance in the exposure light is also good. Can be expected.

Example 5.
A. Phase shift mask blank The phase shift mask blank 10 of Example 5 is a phase shift mask blank 10 in which the back surface reflectance of the phase shift film 30 in the exposure light is reduced. In the film formation of the phase shift film 30 in Example 1 described above, first, an argon (Ar) gas and a nitrogen (N ₂ ) gas are contained in the first chamber in a state where the sputtering gas pressure is 0.5 Pa. The mixed gas to be used was introduced. Then, using a MoZrSi target in which the atomic ratio of Mo, Zr, and Si is Mo: Zr: Si = 10: 10: 80, molybdenum, zirconium, and silicon are placed on the main surface of the transparent substrate 20 by reactive sputtering. A MoZrSiN-based underlayer film containing and nitrogen was formed with a film thickness of 105 nm. The atomic ratio in the target for sputtering is an example, and can be appropriately selected according to the desired composition of the phase shift film 30.
_{After that, a mixed gas composed of argon (Ar) gas, nitrogen (N 2} ) gas, and nitric oxide (NO) gas was introduced into the second chamber in a state where the sputtering gas pressure was 1.6 Pa. bottom. Then, using a MoSi target having an atomic ratio of Mo and Si of Mo: Si = 8: 92, MoSiON containing molybdenum, silicon, oxygen, and nitrogen is applied on the lower film of the MoZrSiN system by reactive sputtering. A 44 nm film was formed on the upper layer film of the system to form a phase shift film 30 composed of a laminated film having a lower layer film of MoZrSiN system and an upper layer film of MoSiON system.
Next, in the same manner as in Example 1, an etching mask film 40 having a laminated structure of a CrN layer, a CrC layer, and a CrCON layer is formed on the phase shift film 30, and the phase shift film 30 and the etching are performed on the transparent substrate 20. A phase shift mask blank 10 on which the mask film 40 was formed was obtained.

The refractive index and extinction coefficient of the lower layer film and the upper layer film constituting the phase shift film 30 of the obtained phase shift mask blank 10 were measured using a dummy substrate prepared by setting them on the same tray.
As a result, the refractive index n of the lower layer film of the MoZrSiN system was 2.45 (wavelength: 405 nm), and the extinction coefficient k was 0.11 (wavelength: 405 nm). The refractive index n of the upper layer film of the MoSiN system was 2.24 (wavelength: 405 nm), and the extinction coefficient k was 0.14 (wavelength: 405 nm).
Further, with respect to the phase shift film 30 of the obtained phase shift mask blank 10, the transmittance and the phase difference were measured in the same manner as in Example 1. As a result, the transmittance is 51% (wavelength: 405 nm), the phase difference is 180 ° (wavelength: 405 nm), the back surface reflectance is 9.8% (wavelength: 405 nm), and the front surface reflectance is 14.9% (wavelength: 405 nm). It was 405 nm).

Further, in the same manner as in Example 1, the phase shift film 30 of the obtained phase shift mask blank 10 was subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS).
In the composition analysis result in the depth direction by XPS for the phase shift mask blank 10, the phase shift film 30 has a composition gradient region at the interface between the transparent substrate 20 and the phase shift film 30, and the phase shift film 30 and the etching mask film 40. Except for the composition gradient region of the interface with, the content of each constituent element is almost constant in the depth direction, and the underlayer film has 3 atomic% of Mo, 5 atomic% of Zr, and 42 atoms of Si. %, N was 47 atomic%, and O was 3 atomic%. The atomic ratio of molybdenum and zirconium was Mo: Zr = 1: 1 and was in the range of Mo: Zr = 1: 0.67 to 1: 4. The content ratio of silicon to the total of molybdenum, zirconium and silicon was 84 atomic%, which was in the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic%. The upper film contained 6 atomic% of Mo, 41 atomic% of Si, 47 atomic% of N, and 6 atomic% of O. It is considered that the oxygen is contained in the lower layer film because a small amount of oxygen was present in the chamber at the time of film formation.

B. Phase shift mask and method for manufacturing the phase shift mask 100 is produced in the same manner as in the above-described embodiment, and the cross-sectional shape of the phase shift film pattern 30a and the surface of the exposed transparent substrate 20 after the phase shift film 30 is removed. I checked the status. In the cross-sectional view, the angle formed by the edge of the phase shift film pattern 30a of the phase shift mask 100 and the main surface of the transparent substrate 20 is 72 °, which exceeds 70 °, and the phase shift film pattern 30a has a cross-sectional shape close to vertical. Had had. Further, when the LER of the phase shift film pattern 30a was observed in the same manner as in Example 1, the edge of the phase shift film pattern (hole pattern) 30a was smooth and substantially linear, which was good. That is, no conspicuous uneven shape was confirmed at the edge of the phase shift film pattern 30a viewed from above. The phase shift film pattern 30a formed on the phase shift mask 100 of Example 5 had a cross-sectional shape capable of sufficiently exerting the phase shift effect. Further, the surface of the exposed transparent substrate 20 after the phase shift film 30 was removed was smooth, and the decrease in transmittance due to the surface roughness of the transparent substrate 20 was negligible. Moreover, when the obtained phase shift mask 100 was observed by electron diffraction, it was confirmed that it had an amorphous structure. Further, no penetration of the etching solution or the like was observed at either the interface of the phase shift film pattern 30a with the etching mask film pattern 40b and the interface with the transparent substrate 20, and the chemical resistance was also good. .. Therefore, an excellent phase shift effect can be obtained in an exposure light containing light in a wavelength range of 313 nm or more and 500 nm or less, more specifically, in an exposure light of composite light containing at least one of i-line, h-line and g-line. The phase shift mask 100 to have was obtained.
Therefore, when the phase shift mask 100 of Example 5 is set on the mask stage of the exposure apparatus and exposure-transferred to the resist film on the substrate for the display device, a fine pattern of less than 2.0 μm can be transferred with high accuracy. It can be said that it can be done. Further, since the phase shift film 30 (phase shift film pattern 30a) is a dense film formed in a state where the degree of vacuum is as low as 0.5 Pa or less, the light resistance in the exposure light is also good. Can be expected.

Comparative example 1.
A. In Comparative Example 1, the phase shift mask blank 10 and the phase shift mask 100 were manufactured by the same structure and method as in Example 1 except for the phase shift film 30. In Comparative Example 1, the atomic ratios of Mo, Zr, and Si of the sputtering target when forming the phase shift film 30 in Example 1 described above were appropriately adjusted. The film thickness of the phase shift film was appropriately adjusted so that the transmittance at a wavelength of 405 nm was 20% or more and 80% or less, and the phase difference was in the range of 160 ° to 200 °.
As a result of analyzing the composition of the obtained MoZrSiN-based phase shift film 30 in the same manner as in Example 1, the atomic ratios of Mo and Zr were as follows.
Comparative Example 1
Mo: Zr = 1: 1, [Si / (Mo + Zr + Si)] = 90 atomic%
As described above, in Comparative Example 1, it was in the range of Mo: Zr = 1: 0.67 to 1: 4, but it was out of the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic%. rice field.

B. Phase shift mask and its manufacturing method In the same manner as in Example 1 described above, the phase shift mask 100 is produced, and the cross-sectional shape of the phase shift film pattern 30a and the exposed transparent substrate 20 after the phase shift film 30 is removed. The surface condition was confirmed.
As a result, in Comparative Example 1, the cross-sectional shape of the phase shift film pattern 30a was not significantly different from that of the other examples and was good, but the exposed transparent substrate 20 after the phase shift film 30 was removed. The surface of the surface was rough, and it was visually cloudy. Therefore, the decrease in transmittance due to the surface roughness of the transparent substrate 20 was remarkable.
Therefore, when the phase shift mask 100 of Comparative Example 1 is set on the mask stage of the exposure apparatus and the exposure transfer is performed on the resist film on the substrate for the display device, it is not possible to transfer a fine pattern of less than 2.0 μm. is expected.

Comparative example 2.
A. In Comparative Example 2, the phase shift mask blank 10 and the phase shift mask 100 were manufactured by the same structure and method as in Example 1 except for the phase shift film 30. In Comparative Example 2, the atomic ratios of Mo, Zr, and Si of the sputtering target when forming the phase shift film 30 in Example 1 described above were appropriately adjusted. The film thickness of the phase shift film 30 was appropriately adjusted so that the transmittance at a wavelength of 405 nm was 20% or more and 80% or less and the phase difference was in the range of 160 ° to 200 °.
As a result of analyzing the composition of the obtained MoZrSiN-based phase shift film 30 in the same manner as in Example 1, the atomic ratios of Mo and Zr were as follows.
Comparative Example 2
Mo: Zr = 1: 1, [Si / (Mo + Zr + Si)] = 65 atomic%
As described above, in Comparative Example 2, it was in the range of Mo: Zr = 1: 0.67 to 1: 4, but it was out of the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic%. rice field.

B. Phase shift mask and its manufacturing method In the same manner as in Example 1 described above, the phase shift mask 100 is produced, and the cross-sectional shape of the phase shift film pattern 30a and the exposed transparent substrate 20 after the phase shift film 30 is removed. The surface condition was confirmed.
As a result, in Comparative Example 2, the surface of the exposed transparent substrate 20 after the phase shift film 30 was removed was smooth, and the decrease in transmittance due to the surface roughness of the transparent substrate 20 was negligible. The cross-sectional shape of the film pattern 30a was poor, and the cross-sectional shape could not sufficiently exhibit the phase shift effect.
Therefore, when the phase shift mask 100 of Comparative Example 2 is set on the mask stage of the exposure apparatus and the exposure transfer is performed on the resist film on the substrate for the display device, it is not possible to transfer a fine pattern of less than 2.0 μm. is expected.

Comparative example 3.
A. In Comparative Example 3, the phase shift mask blank 10 and the phase shift mask 100 were manufactured by the same structure and method as in Example 1 except for the phase shift film 30. In Comparative Example 3, the atomic ratios of Mo, Zr, and Si of the sputtering target when forming the phase shift film 30 in Example 1 described above were appropriately adjusted.
As a result of analyzing the composition of the obtained MoZrSiN-based phase shift film 30 in the same manner as in Example 1, in Comparative Example 3, the atomic ratio was Mo: Zr = 2: 1 and 1: 0.67 to It was out of the 1: 4 range. On the other hand, the content ratio of silicon to the total of molybdenum, zirconium and silicon was in the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic%.

B. Phase shift mask and its manufacturing method In the same manner as in Example 1 described above, the phase shift mask 100 is produced, and the cross-sectional shape of the phase shift film pattern 30a and the exposed transparent substrate 20 after the phase shift film 30 is removed. The surface condition was confirmed.
As a result, in Comparative Example 3, the surface of the exposed transparent substrate 20 after the phase shift film 30 was removed was smooth, and the decrease in transmittance due to the surface roughness of the transparent substrate 20 was negligible. Further, the cross-sectional shape of the phase shift film pattern 30a was not significantly different from that of the other examples, and was good. On the other hand, the transmittance at a wavelength of 405 nm was less than 15%, and sufficient transmittance could not be obtained. The film thickness was adjusted in the same manner as in the other examples and comparative examples, but a sufficient transmittance could not be obtained yet.
Therefore, when the phase shift mask 100 of Comparative Example 3 is set on the mask stage of the exposure apparatus and the exposure transfer is performed on the resist film on the substrate for the display device, it is not possible to transfer a fine pattern of less than 2.0 μm. is expected.

Comparative example 4.
A. In Comparative Example 4, the phase shift mask blank 10 and the phase shift mask 100 were manufactured by the same structure and method as in Example 1 except for the phase shift film 30. In Comparative Example 4, the atomic ratios of Mo, Zr, and Si of the sputtering target when forming the phase shift film in Example 1 described above were appropriately adjusted. The film thickness of the phase shift film 30 was appropriately adjusted so that the transmittance at a wavelength of 405 nm was 20% or more and 80% or less and the phase difference was in the range of 160 ° to 200 °.
As a result of analyzing the composition of the obtained MoZrSiN-based phase shift film 30 in the same manner as in Example 1, in Comparative Example 4, the atomic ratio of molybdenum and zirconium was Mo: Zr = 1: 5. It was out of the range of 1: 0.67 to 1: 4. On the other hand, the content ratio of silicon to the total of molybdenum, zirconium and silicon was in the range of [Si / (Mo + Zr + Si)] = 70 to 88 atomic%.

B. Phase shift mask and its manufacturing method In the same manner as in Example 1 described above, the phase shift mask 100 is produced, the cross-sectional shape of the phase shift film pattern, and the surface of the exposed transparent substrate 20 after the phase shift film 30 is removed. I checked the status.
As a result, in Comparative Example 4, the surface of the exposed transparent substrate 20 after removing the phase shift film 30 was smooth, and the decrease in transmittance due to the surface roughness of the transparent substrate 20 was negligible, but it was sufficient. The chemical resistance was not obtained, and the cross-sectional shape of the phase shift film pattern 30a was deteriorated as compared with other examples. Further, both the front surface reflectance and the back surface reflectance at a wavelength of 405 nm were high, and sufficient transfer accuracy could not be obtained.
Therefore, when the phase shift mask 100 of Comparative Example 4 is set on the mask stage of the exposure apparatus and the exposure transfer is performed on the resist film on the substrate for the display device, it is not possible to transfer a fine pattern of less than 2.0 μm. is expected.

10 ... Phase shift mask blank, 20 ... Transparent substrate, 30 ... Phase shift film, 30a ... Phase shift film pattern, 40 ... Etching mask film, 40a ... First etching mask film pattern, 40b ... Second etching mask film pattern , 50 ... 1st resist film pattern, 60 ... 2nd resist film pattern, 100 ... phase shift mask

Claims (9)

A photomask blank having a phase shift film on a transparent substrate.
The photomask blank is an original plate for forming a photomask, and the photomask is a photomask having a phase shift film pattern obtained by wet etching the phase shift film on the transparent substrate. ,
The phase shift film is composed of a single layer or multiple layers, and 50% or more and 100% or less of the total film thickness of the phase shift film is molybdenum (Mo), zirconium (Zr), silicon (Si), and nitrogen. Contains a MoZrSi-based material layer made of a material containing and
In the MoZrSi-based material layer, the atomic ratio of molybdenum and zirconium is Mo: Zr = 1.5: 1 to 1: 4, and the content ratio of silicon to the total of molybdenum, zirconium and silicon is 70 to 88. A photomask blank characterized by being atomic%. Claim 1 is characterized in that the phase shift film has optical characteristics such that the transmittance is 20% or more and 80% or less with respect to the representative wavelength of the exposure light and the phase difference is 160 ° or more and 200 ° or less. The photomask blank described. The phase shift film is a laminated film including a lower layer on the transparent substrate side and an upper layer laminated on the lower layer, and the lower layer is the MoZrSi-based material layer. 2. The photomask blank according to 2. The photomask blank according to claim 3, wherein the upper layer is made of a material having a representative wavelength of exposure light, which is smaller than the refractive index of the lower layer and higher than the extinction coefficient. The phase shift film is characterized in that the refractive index, extinction coefficient, and film thickness of each of the upper layer and the lower layer are set so that the back surface reflectance with respect to the representative wavelength of the exposure light is 15% or less. The photomask blank according to claim 4. The photomask blank according to any one of claims 1 to 5, wherein an etching mask film having different etching selectivity with respect to the phase shift film is provided on the phase shift film. The step of preparing the photomask blank according to any one of claims 1 to 5,
A step of forming a resist film on the phase shift film, wet-etching the phase shift film using the resist film pattern formed from the resist film as a mask, and forming a phase shift film pattern on the transparent substrate. A method for producing a photo mask, which comprises. The step of preparing the photomask blank according to claim 6 and
A step of forming a resist film on the etching mask film, wet-etching the etching mask film using the resist film pattern formed from the resist film as a mask, and forming an etching mask film pattern on the phase shift film. ,
A method for producing a photomask, which comprises a step of wet-etching the phase shift film using the etching mask film pattern as a mask to form a phase shift film pattern on the transparent substrate. The photomask obtained by the photomask manufacturing method according to claim 7 or 8 is placed on a mask stage of an exposure apparatus, and a transfer pattern including the phase shift film pattern formed on the photomask is displayed. A method for manufacturing a display device, which comprises an exposure step of performing exposure transfer to a resist formed on a device substrate.

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