JP7126836B2 - PHASE SHIFT MASK BLANK, METHOD FOR MANUFACTURING PHASE SHIFT MASK USING SAME, AND PATTERN TRANSFER METHOD - Google Patents

Description

The present invention relates to a phase shift mask blank, a phase shift mask manufacturing method using the same, and a pattern transfer method.

2. Description of the Related Art In recent years, as display devices such as FPDs (Flat Panel Displays) have become higher in resolution and definition, there is a demand for a phase shift mask for manufacturing display devices in which fine patterns are formed.

In conventional general phase shift mask blanks used for manufacturing phase shift masks for manufacturing display devices, on a mask substrate made of synthetic silica glass (hereinafter sometimes referred to as a synthetic silica glass substrate), A phase shift film is formed, and a light shielding film is further formed on the phase shift film. When the phase shift film is made of MoSiN, it has a transmittance of about 5% for the i-line used as the exposure light and a reflectance of 11% for the light incident from the mask substrate side.

Patent Document 1 describes a phase shift mask for manufacturing LSIs and a phase shift mask blank used for the manufacture thereof. The phase shift mask blank described in Patent Document 1 includes a transparent substrate, a highly reflective material layer disposed on the transparent substrate, a phase-shifting layer disposed on the highly reflective material layer, and a phase-shifting layer on the phase-shifting layer. and a light blocking layer disposed in a. The translucent substrate is made of quartz. The highly reflective material layer has a reflectance of 20% to 90% with respect to the amount of irradiated light. The highly reflective material layer includes silicon (Si), molybdenum (Mo), tantalum (Ta), zirconium (Zr), aluminum (Al), titanium (Ti), platinum (Pt), ruthenium (Ru), and chromium (Cr). , tin (Sn). The highly reflective material layer may additionally include one of oxygen (O) and nitrogen (N). The phase-inverting layer is made of molybdenum silicon (MoSi), molybdenum silicon nitride (MoSiN), or silicon oxide (SiO2). The light blocking layer is made of chromium (Cr).

In recent years, as display devices such as FPDs have become larger, mask substrates have also become larger. When the size of the mask substrate increases, the thermal deformation of the mask substrate due to absorption of the exposure light increases, and there is a possibility that the position of the pattern formed on the photomask may change. For this reason, it is desired to form the mask substrate using a material with extremely low thermal expansion. Patent Document 2 describes a mask substrate (hereinafter sometimes referred to as a TiO2--SiO2 glass substrate) made of a material obtained by adding TiO2 to quartz glass. This substrate has a small coefficient of thermal expansion. Further, Patent Document 3 describes a mask blank and a photomask in which a light-shielding film is formed on a TiO2--SiO2 glass substrate, and an antireflection film is further formed on the light-shielding film.

JP 2015-152924 A Retable 2010/010915 JP 2010-26398 A

As described above, the transmittance of the phase shift film used for conventional general phase shift mask blanks is about 5%. If the transmittance is small, it is caused by the thermal expansion of the phase shift film pattern due to the absorption of the exposure light in the phase shift film due to repeated use in the phase shift mask used for the manufacture of the FPD such as the next-generation organic EL panel. There is a concern that a positional change of the phase shift film pattern will occur.
Since the phase shift mask of Patent Document 1 is for LSI manufacturing, the phase shift film pattern is generally formed by dry etching. The fact that the phase shift mask of Patent Document 1 is for LSI manufacturing is because the prior art of Cited Document 1 (see paragraph 0002 of Cited Document 1) describes a photomask used in the manufacture of semiconductor elements. It is clear from In the case of a phase shift mask for manufacturing display devices such as FPDs, the phase shift film pattern is formed by wet etching. When patterning a phase shift film composed of a highly reflective material layer and a phase inverting layer in Patent Document 1 by wet etching, the etching rate of the highly reflective material layer and the phase inverting layer are extremely different, resulting in a phase shift film pattern. There is a risk that the cross-sectional shape and CD variation will deteriorate.

Therefore, the present invention has been made in view of the above-described problems. An object of the present invention is to provide a phase shift mask blank for manufacturing a phase shift mask capable of suppressing positional change, and a method for manufacturing a phase shift mask using the same.
Another object of the present invention is to provide a phase shift mask blank which can form a phase shift film pattern with a good cross-sectional shape and small CD variation by wet etching, and a method for manufacturing a phase shift mask using the same. .

The inventors of the present invention have made intensive studies to achieve the above-described object, and have found that a phase shift film is arranged on a lower layer having a function of adjusting the reflectance with respect to light incident from the transparent substrate side, and on the upper side of the lower layer. By devising the composition of the materials forming the upper and lower layers constituting the phase shift film, the phase shift film is incident from the transparent substrate side. By making the reflectance (back surface reflectance) for light in the wavelength range of 365 nm to 436 nm greater than 20%, the absorption of exposure light in the phase shift film is reduced, and the positional change of the phase shift film pattern is suppressed. I have come to the realization that it is possible. In particular, when the exposure light is compound light containing light of a plurality of wavelengths selected from the wavelength range of 365 nm to 436 nm, in addition to the optical properties of the back surface reflectance of the phase shift film, the transparent substrate of the phase shift film By setting the fluctuation range of the reflectance (back surface reflectance) for light in the wavelength range of 365 nm to 436 nm incident from the side to 10% or less, the absorption of the exposure light in the phase shift film is reduced, and the phase shift film pattern is formed. It has been found that the change in the position of the can be suppressed. In addition, by devising the composition of the materials forming the upper and lower layers constituting the phase shift film, it is possible to etch the upper and lower layers using the same etchant when patterning the phase shift film, and the etching speed of the upper layer is improved. By setting the ratio of the etching rate of the lower layer to more than 1 and 10 or less, it is possible to form a phase shift film pattern with a good cross-sectional shape and small CD variation by wet etching.

The present invention has been made based on this finding, and has the following configurations.

(Configuration 1)
A phase shift mask blank for manufacturing a phase shift mask for manufacturing a display device having a phase shift film pattern on a transparent substrate,
comprising a transparent substrate and a phase shift film formed on the transparent substrate;
The phase shift film includes a lower layer having a function of adjusting reflectance with respect to light incident from the transparent substrate side, and an upper layer disposed above the lower layer and having a function of adjusting transmittance and phase difference with respect to exposure light. and at least
The phase shift film has a predetermined optical characteristic of transmittance and phase difference with respect to exposure light,
The phase shift film has a reflectance of more than 20% with respect to light in the wavelength range of 365 nm to 436 nm incident from the transparent substrate side, and reflects light in the wavelength range of 365 nm to 436 nm incident from the transparent substrate side. 1. A phase shift mask blank, characterized in that the fluctuation width of the ratio is 10% or less.

(Configuration 2)
The phase shift mask according to Structure 1, wherein the phase shift film has a transmittance of 1% or more and 50% or less and a phase difference of 160° or more and 200° or less for light with a wavelength of 365 nm contained in the exposure light. blank.

(Composition 3)
the upper layer is composed of a material containing metal and one or both of oxygen and nitrogen;
The lower layer is made of a material containing a metal,
The upper layer and the lower layer are made of a material that can be etched using the same etchant when patterning the phase shift film, and the ratio of the etching rate of the lower layer to the etching rate of the upper layer is more than 1 and 10 or less. The phase shift mask blank according to configuration 1 or 2, characterized in that:

(Composition 4)
The phase shift mask blank according to Structure 3, wherein the phase shift film has an etching rate of 0.06 nm/sec or more and 2.5 nm/sec or less in the etchant.

(Composition 5)
Materials constituting the upper layer include a material consisting of metal and oxygen, a material consisting of metal and nitrogen, a material consisting of metal, oxygen and nitrogen, a material consisting of metal, silicon and oxygen, and a material consisting of metal, silicon and nitrogen. and a material consisting of metal, silicon, oxygen and nitrogen, and a component that speeds up or slows down the etching rate of the upper layer in an etchant used when patterning the phase shift film on these materials 5. The phase shift mask blank of any one of the preceding arrangements 1-4, wherein the phase shift mask blank is selected from materials containing

(Composition 6)
The material constituting the lower layer is a material made of metal, a material made of metal and silicon, and an etchant used for patterning the phase shift film on these materials to increase the etching rate of the lower layer. 5. A phase-shifting mask blank according to any one of arrangements 1 to 4, characterized in that it is selected from a material plus a component or a retarding component.

(Composition 7)
Structures 3 to 6, wherein the metal contained in the material forming the upper layer and the metal contained in the material forming the lower layer are each at least one selected from titanium, zirconium, molybdenum and tantalum. A phase-shifting mask blank according to any one of claims 1 to 3.

(Composition 8)
8. The phase shift mask blank according to any one of Structures 3 to 7, wherein the metal contained in the material constituting the upper layer is at least one selected from titanium and zirconium.

(Composition 9)
The phase shift mask blank according to Structure 6, wherein the metal contained in the material forming the lower layer is molybdenum, and the component that slows down the etching rate of the lower layer is carbon.

(Configuration 10)
10. The phase shift mask blank according to any one of Structures 1 to 9, wherein the transparent substrate is made of SiO2-TiO2 based glass.

(Composition 11)
11. The phase shift mask blank according to any one of Structures 1 to 10, further comprising a light shielding film formed on the phase shift film.

(Composition 12)
In a method for manufacturing a phase shift mask for manufacturing a display device,
a resist pattern forming step of forming a resist pattern on the phase shift film of the phase shift mask blank according to any one of structures 1 to 10;
and a phase shift film pattern forming step of forming a phase shift film pattern by wet-etching the phase shift film using the resist pattern as a mask.

(Composition 13)
In a method for manufacturing a phase shift mask for manufacturing a display device,
a resist pattern forming step of forming a resist pattern on the light shielding film of the phase shift mask blank according to Structure 11;
a light-shielding film pattern forming step of forming a light-shielding film pattern by wet-etching the light-shielding film using the resist pattern as a mask;
and a phase shift film pattern forming step of forming a phase shift film pattern by wet-etching the phase shift film using the light shielding film pattern as a mask.

(Composition 14)
14. A pattern transfer method, comprising irradiating exposure light to a phase shift mask obtained by the method for manufacturing a phase shift mask according to Structure 12 or 13 to transfer a pattern onto a display device substrate.

(Composition 15)
15. The pattern transfer method according to structure 14, wherein the exposure light is compound light containing light of a plurality of wavelengths selected from a wavelength range of 365 nm to 436 nm.

As described above, in the phase shift mask blank according to the present invention, the phase shift film has a reflectance (back surface reflectance) of more than 20% with respect to light in the wavelength range of 365 nm or more and 436 nm or less incident from the transparent substrate side. By reducing the absorption of the exposure light in the phase shift film, it is possible to suppress the positional change of the phase shift film pattern caused by the thermal expansion of the phase shift film pattern. In addition to the optical characteristics of the back surface reflectance of the phase shift film, the fluctuation range of the reflectance (back surface reflectance) of the phase shift film with respect to light in the wavelength range of 365 nm to 436 nm incident from the transparent substrate side is 10% or less. Therefore, when the exposure light is compound light containing light of a plurality of wavelengths selected from the wavelength range of 365 nm to 436 nm, the phase shift film can be further reduced by reducing the absorption of the exposure light by the phase shift film. Positional change of the phase shift film pattern due to thermal expansion of the pattern can be suppressed. In the phase shift mask blank according to the present invention, the upper layer and the lower layer are made of a material that can be etched using the same etchant when patterning the phase shift film, and the ratio of the etching rate of the lower layer to the etching rate of the upper layer is is more than 1 and 10 or less, a phase shift film pattern having a good cross-sectional shape and small CD variation can be formed by wet etching. Therefore, it is possible to obtain a phase shift mask blank capable of manufacturing a phase shift mask capable of accurately transferring a high-definition phase shift film pattern.

A method of manufacturing a phase shift mask according to the present invention is characterized by using the above phase shift mask blank of the present invention. Therefore, a phase shift film pattern with little positional change can be formed. In addition, a phase shift film pattern having a good cross-sectional shape and small CD variation can be formed. Therefore, it is possible to manufacture a phase shift mask capable of accurately transferring a fine phase shift film pattern.

FIG. 2 is a schematic diagram showing the film configuration of a phase shift mask blank; It is a schematic diagram which shows the manufacturing process of a phase shift mask.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following embodiment is one form for embodying the present invention, and does not limit the scope of the present invention. In addition, in the drawings, the same or equivalent parts may be denoted by the same reference numerals, and the description thereof may be simplified or omitted.

Embodiment 1.
Embodiment 1 describes a phase shift mask blank.

FIG. 1 is a schematic diagram showing the film structure of a phase shift mask blank 10. As shown in FIG.
A 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 a light shielding film 40 formed on the phase shift film 30 .

The transparent substrate 20 is transparent to exposure light. The transparent substrate 20 has a transmittance of 85% or more, preferably 90% or more, with respect to exposure light, assuming that there is no surface reflection loss. The transparent substrate 20 is made of a material containing silicon and oxygen, and can be made of a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO2--TiO2 glass, etc.). . When the transparent substrate 20 is made of low thermal expansion glass, it is possible to suppress the positional change of the phase shift film pattern due to the thermal deformation of the transparent substrate 20 .

The phase shift film 30 is arranged on a lower layer 31 having a function of adjusting the reflectance (hereinafter sometimes referred to as back surface reflectance) for light incident from the transparent substrate 20 side, and on the upper side of the lower layer 31, and is arranged above the exposure light. and an upper layer 32 having the function of adjusting the transmittance and phase difference for the light.
The back surface reflectance of the phase shift film 30 is mainly affected by the lower layer 31 , and the phase difference and transmittance of the phase shift film 30 are mainly affected by the upper layer 32 .
The lower layer 31 and the upper layer 32 can be formed by a sputtering method.

The transmittance of the phase shift film 30 is 1% or more, preferably 3% or more, with respect to light with a wavelength of 365 nm contained in the exposure light. Further, the transmittance of the phase shift film 30 is 70% or less, preferably 50% or less, more preferably 40% or less, with respect to the light with a wavelength of 365 nm contained in the exposure light. From the above, the transmittance of the phase shift film 30 is 1% or more and 70% or less, preferably 1% or more and 50% or less, and 3% or more and 40% with respect to the light having a wavelength of 365 nm contained in the exposure light. It is more preferable that it is below.
The transmittance can be measured using a phase shift amount measuring device or the like.

The phase difference of the phase shift film 30 is 160° or more, preferably 170° or more, with respect to the light with a wavelength of 365 nm contained in the exposure light. Further, the phase difference of the phase shift film 30 is 200° or less, more preferably 190° or less, with respect to the light with a wavelength of 365 nm contained in the exposure light.
The phase difference can be measured using a phase shift amount measuring device or the like.

The back surface reflectance of the phase shift film 30 is more than 20%, preferably 25% or more, and more preferably 30% or more, with respect to light in the wavelength range from 365 nm to 436 nm. Further, the rear surface reflectance of the phase shift film 30 is preferably 60% or less, more preferably 55% or less, with respect to light in the wavelength range from 365 nm to 436 nm. When the back surface reflectance is more than 20%, positional change of the phase shift film pattern due to thermal expansion of the phase shift film can be suppressed. From the above, the back surface reflectance of the phase shift film 30 is preferably 25% or more and 60% or less, more preferably 30% or more and 55% or less.
In addition, the fluctuation width of the rear surface reflectance of the phase shift film 30 is 10% or less, preferably 7% or less, more preferably 5% or less in the wavelength range from 365 nm to 436 nm.
The back surface reflectance can be measured using a spectrophotometer or the like. Also, the fluctuation width of the back surface reflectance is the difference between the maximum value and the minimum value of the back surface reflectance in the wavelength range from 365 nm to 436 nm.

The upper layer 32 contains a metal and one or both of oxygen and nitrogen so that the phase shift film 30 has the back surface reflectance and the variation width of the back surface reflectance, and the phase difference and the transmittance. The lower layer 31 is made of a material containing metal.

More specifically, the material constituting the upper layer 32 includes a material composed of metal and oxygen, a material composed of metal and nitrogen, a material composed of metal, oxygen and nitrogen, a material composed of metal, silicon and oxygen, A material consisting of metal, silicon and nitrogen and a material consisting of metal, silicon, oxygen and nitrogen can be mentioned. Metal, silicon, oxygen, and nitrogen are the major constituents of the materials that make up top layer 32 . In addition, materials to which a component that speeds up or slows down the etching rate of the upper layer 32 in the etchant used when patterning the phase shift film 30 is added to these materials.
A transition metal is preferable as the metal that is the main component of the material that constitutes the upper layer 32 . Molybdenum (Mo), titanium (Ti), zirconium (Zr), and the like are examples of transition metals that are the main component of the material forming the upper layer 32 . When the transition metals, which are the main components contained in the material forming the upper layer 32, are titanium (Ti), zirconium (Zr), and molybdenum (Mo), the phase difference and the transmittance are adjusted to the values required for the phase shift film 30. Easy to adjust. Further, when the transition metals, which are the main components contained in the material constituting the upper layer 32, are titanium (Ti) and zirconium (Zr), the etching rate of the upper layer 32 in the etchant used when patterning the phase shift film 30 is is faster, and the etching time of the phase shift film 30 can be shortened. The material forming the upper layer 32 may contain two or more kinds of metals as main components.
When the material constituting the upper layer 32 contains a component that increases the etching rate, the content of the component that increases the etching rate of the upper layer 32 is smaller than the content of each main component contained in the material that constitutes the upper layer 32. A specific example of a component that increases the etching rate of the upper layer 32 is aluminum (Al).
When the material constituting the upper layer 32 contains a component that slows down the etching rate, the content of the component that slows down the etching rate of the upper layer 32 is smaller than the content of each main component contained in the material that constitutes the upper layer 32. Specifically, carbon (C) and tantalum (Ta) are listed as components that slow down the etching rate of the upper layer 32 .
It is within the scope of the present invention that other elements are contained within the range that does not affect the characteristics of the upper layer 32 .

More specifically, the material forming the lower layer 31 includes a material made of metal and a material made of metal and silicon. Metal and silicon are the main components of the material that makes up the lower layer 31 . In addition, materials to which a component that slows down or speeds up the etching rate of the lower layer 31 in the etchant used when patterning the phase shift film 30 is added to these materials.
A transition metal is preferable as the metal that is the main component of the material that constitutes the lower layer 31 . Molybdenum (Mo), titanium (Ti), zirconium (Zr), and the like are examples of transition metals that are the main component of the material forming the lower layer 31 . When the transition metals that are the main components contained in the material forming the upper layer 32 are titanium (Ti), zirconium (Zr), and molybdenum (Mo), the transition metals that are the main components contained in the material forming the lower layer 31 are preferably titanium (Ti), zirconium (Zr), and molybdenum (Mo). When the transition metals, which are the main components contained in the material forming the lower layer 31, are titanium (Ti), zirconium (Zr), and molybdenum (Mo), when patterning the phase shift film 30, the upper layer 32 and the lower layer 31 can be easily etched using the same etchant. The material forming the lower layer 31 may contain two or more kinds of metals as main components.
When the material constituting the lower layer 31 contains a component that slows down the etching rate, the content of the component that slows down the etching rate of the lower layer 31 is smaller than the content of each main component contained in the material that constitutes the lower layer 31. Specific examples of components that slow down the etching rate of the lower layer 31 include carbon (C), silicon (Si), and tantalum (Ta).
When the material constituting the lower layer 31 contains a component that increases the etching rate, the content of the component that increases the etching rate of the lower layer 31 is smaller than the content of each main component contained in the material that constitutes the lower layer 31. A specific example of a component that increases the etching rate of the lower layer 31 is aluminum (Al).
It should be noted that it is within the scope of the present invention even if other elements are contained within a range that does not affect the properties of the lower layer 31 .

When the lower layer 31 contains one or both of oxygen and nitrogen, the total oxygen and nitrogen content of the lower layer 31 is preferably smaller than the total oxygen and nitrogen content of the upper layer 32 .
When the content of oxygen and nitrogen contained in the lower layer 31 is small, the sheet resistance of the phase shift film is lowered, so that electrostatic breakdown of the phase shift film pattern formed on the phase shift mask can be prevented.
The total content of oxygen and nitrogen can be measured using an Auger electron spectrometer, an X-ray photoelectron spectrometer (XPS), or the like.

Upper layer 32 and lower layer 31 are composed of materials that can be etched using the same etchant when patterning phase shift film 30 . Moreover, when the upper layer 32 and the lower layer 31 are etched using the same etchant, the ratio of the etching rate of the lower layer 31 to the etching rate of the upper layer 32 is more than 1 and 10 or less. When the etching rate ratio is more than 1 and 10 or less, the cross-sectional shape of the phase shift film pattern after wet etching is good, and the CD variation is small. The ratio of the etching rate of the lower layer 31 to the etching rate of the upper layer 32 is preferably more than 1 and 5 or less, more preferably more than 1 and 3 or less.
The ratio of the etching rate of the lower layer 31 to the etching rate of the upper layer 32 in the example was obtained by preparing samples in which the upper layer 32 and the lower layer 31 were separately formed on the transparent substrate 20 under respective film forming conditions. and the etching rate of the sample of the lower layer 31 from the etching time and film thickness, and then dividing the etching rate of the sample of the lower layer 31 by the etching rate of the sample of the upper layer 32 .
As a method for calculating the etching rate ratio other than the above, the reflectance of the films of the upper layer 32 and the lower layer 31 during etching is measured to detect the etching end point of the upper layer 32 and the lower layer 31, and the thickness of each layer and the etching rate are calculated. There is a method of dividing the etching rate of the lower layer 31 by the etching rate of the upper layer 32 after calculating the etching rate of the upper layer 32 and the lower layer 31 from the end time.
The etching rate of the phase shift film 30 in the etchant for etching the upper layer 32 and the lower layer 31 is preferably 0.06 nm/sec or more, more preferably 0.2 nm/sec or more. Also, the etching rate of the phase shift film 30 in the etchant for etching the upper layer 32 and the lower layer 31 is preferably 2.5 nm/sec or less, more preferably 2.0 nm/sec or less.
Etching solutions for etching the upper layer 32 and the lower layer 31 when patterning the phase shift film 30 include fluorine compounds such as ammonium hydrogen fluoride and ammonium fluoride, and oxidizing agents such as phosphoric acid, nitric acid, sulfuric acid, and hydrogen peroxide. can be used. Examples thereof include an etchant containing ammonium hydrogen fluoride and hydrogen peroxide , and an etchant containing ammonium fluoride, phosphoric acid, and hydrogen peroxide.

Examples of materials forming the upper layer 32 include MoSiN, MoSiON, MoSiO, ZrSiN, ZrSiON, ZrSiO, TiO, TiON, TiSiO, and TiSiON. In addition, those to which C or Ta is added as a component to slow down the etching rate, and those to which Al is added as a component to increase the etching rate can be used.
Examples of materials forming the lower layer 31 include Mo, MoSi, Ta, TaSi, Zr, ZrSi, Ti, and TiSi. In addition, those to which C or Ta is added as a component to slow down the etching rate, and those to which Al is added as a component to increase the etching rate can be used.
Suitable combinations of the upper layer 32 and the lower layer 31 include, for example, a combination of the upper layer 32 of MoSiN and the lower layer 31 of MoSiC (Example 1), a combination of the upper layer 32 of ZrSiN and the lower layer 31 of MoSi (Example 2), and the upper layer 32 of Examples include a combination of TiO2 and MoSi for the lower layer 31 (Example 3), and a combination of ZrSiON for the upper layer 32 and ZrSi for the lower layer 31 (Example 4).

The thicknesses of the upper layer 32 and the lower layer 31 are adjusted so that the phase shift film 30 has the back surface reflectance and the fluctuation range of the back surface reflectance, and the phase difference and the transmittance. From the viewpoint of the cross-sectional shape of the phase shift film pattern, a thin film is preferable as much as possible. The thickness of the upper layer 32 is preferably 180 nm or less, more preferably 160 nm or less. The thickness of the lower layer 31 is preferably 3 nm or more, and more preferably 5 nm or more, from the viewpoint of thickness uniformity within the substrate surface, because the thickness of the lower layer 31 is the back surface reflectance and the fluctuation range of the back surface reflectance. From the viewpoint of the cross-sectional shape of the phase shift film pattern, the thickness of the lower layer 31 is preferably as thin as possible. Specifically, the thickness of the lower layer 31 is preferably 50 nm or less, more preferably 30 nm or less.

Each of the lower layer 31 and the upper layer 32 may be composed of a single film having a uniform composition, may be composed of a plurality of films having different compositions, or may have a continuous composition in the thickness direction. It may be composed of a single film that changes to

The light shielding film 40 is made of a material that is chemically resistant to the etchant used when patterning the phase shift film 30 . A preferable material for the light shielding film 40 is a chromium-based material. More specifically, chromium (Cr) or chromium (Cr) and at least one of carbon (C), nitrogen (N), oxygen (O), and fluorine (F) are used as the chromium-based material. material containing. For example, Cr, CrC, CrN, CrO, CrCN, CrON, CrCO, and CrCON are examples of materials that constitute the light shielding film 40 .
The light shielding film 40 can be formed by a sputtering method.

In the portion where the phase shift film 30 and the light shielding film 40 are laminated, the optical density with respect to exposure light is preferably 3 or more, more preferably 4 or more.
Optical density can be measured using a spectrophotometer, an OD meter, or the like.

The light shielding film 40 may be composed of a single film with a uniform composition, may be composed of a plurality of films with different compositions, or may be composed of a single film whose composition varies continuously in the thickness direction. It may be composed of one film.

Although the phase shift mask blank 10 shown in FIG. 1 has the light shielding film 40 on the phase shift film 30, the phase shift mask blank which does not have the light shielding film 40 on the phase shift film 30 can also be used. can be applied. The present invention can also be applied to a phase shift mask blank having a light shielding film 40 on the phase shift film 30 and a resist film on the light shielding film 40 . Furthermore, the present invention can also be applied to a phase shift mask blank having no light shielding film 40 on the phase shift film 30 and having a resist film on the phase shift film 30 .

Next, a method for manufacturing the phase shift mask blank 10 of this embodiment will be described. The phase shift mask blank 10 shown in FIG. 1 is manufactured by performing the following phase shift film forming process and light shielding film forming process.
Each step will be described in detail below.

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, low thermal expansion glass (SiO2--TiO2 glass, etc.), as long as it is transparent to exposure light. can be anything.

Next, a phase shift film 30 is formed on the transparent substrate 20 by sputtering. Phase shift film 30 is formed by depositing lower layer 31 on the main surface of transparent substrate 20 and depositing upper layer 32 on lower layer 31 .

The film formation of the lower layer 31 is performed using a sputtering target containing a metal which is the main component of the material constituting the lower layer 31 or a sputtering target containing the metal and silicon, for example, helium gas, neon gas, argon gas, krypton gas and It is carried out in a sputtering gas atmosphere comprising an inert gas containing at least one selected from the group consisting of xenon gas. When carbon, which is a component that slows down the etching rate of the lower layer 31, is included in the material forming the lower layer 31, a carbon dioxide gas, a hydrocarbon-based gas, or the like is added to the sputtering gas atmosphere. Hydrocarbon gases include, for example, methane gas, butane gas, propane gas, and styrene gas. When the material forming the lower layer 31 contains tantalum, which is a component that slows down the etching rate of the lower layer 31, a sputtering target containing tantalum is used. When aluminum, which is a component that increases the etching rate of the lower layer 31, is included in the material forming the lower layer 31, a sputtering target containing aluminum is used.
Similarly, the upper layer 32 is deposited using a sputtering target containing metal and silicon, which are the main components of the material that constitutes the upper layer 32, for example, helium gas, neon gas, argon gas, krypton gas, and xenon gas. Conducted in a sputtering gas atmosphere consisting of a mixed gas of an inert gas containing at least one selected from the group and an active gas containing at least one selected from the group consisting of oxygen gas, nitrogen gas, nitrogen monoxide gas and nitrogen dioxide gas. will be When the material constituting the upper layer 32 contains aluminum, which is a component that increases the etching rate of the upper layer 32, a sputtering target containing aluminum is used. When carbon, which is a component that slows down the etching rate of the upper layer 32, is included in the material forming the upper layer 32, carbon dioxide gas, hydrocarbon-based gas, or the like is added to the sputtering gas atmosphere. Hydrocarbon gases include, for example, methane gas, butane gas, propane gas, and styrene gas. If the material forming upper layer 32 contains tantalum, which is a component that slows down the etching rate of upper layer 32, a sputter target containing tantalum is used.

When the lower layer 31 and the upper layer 32 are formed, the composition and thickness of each of the lower layer 31 and the upper layer 32 are such that the phase shift film 30 has the above-described rear surface reflectance and the fluctuation range of the rear surface reflectance, and the above-described phase difference and transmittance. The composition of each of the lower layer 31 and the upper layer 32 can be controlled by the composition and flow rate of the sputtering gas. The thickness of each of the lower layer 31 and the upper layer 32 can be controlled by sputtering power, sputtering time, and the like. Moreover, when the sputtering apparatus is an in-line type sputtering apparatus, the thickness of each of the lower layer 31 and the upper layer 32 can be controlled also by the transport speed of the substrate.

When the lower layer 31 is composed of a single film having a uniform composition, the film formation process described above is performed only once without changing the composition and flow rate of the sputtering gas. When the lower layer 31 is composed of a plurality of films with different compositions, the film formation process described above is performed a plurality of times while changing the composition and flow rate of the sputtering gas for each film formation process. When the lower layer 31 is composed of a single film whose composition changes continuously in the thickness direction, the film formation process described above is performed only once while changing the composition and flow rate of the sputtering gas. The film formation of the upper layer 32 is the same. When the film formation process is performed multiple times, the sputtering power applied to the sputtering target can be reduced.

2. Light-Shielding Film Forming Step After forming the phase shift film 30, a light-shielding film 40 is formed on the phase shift film 30 by sputtering.
A phase shift mask blank 10 is thus obtained.

The light-shielding film 40 is formed using a sputtering target containing chromium or a chromium compound, for example, from an inert gas containing at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas. or an inert gas containing at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas and xenon gas, oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, It is carried out in a sputtering gas atmosphere consisting of a mixed gas with an active gas containing at least one selected from the group consisting of carbon dioxide gas, hydrocarbon-based gas and fluorine-based gas. Hydrocarbon gases include, for example, methane gas, butane gas, propane gas, and styrene gas.

When the light-shielding film 40 is composed of a single film with a uniform composition, the above-described film formation process is performed only once without changing the composition and flow rate of the sputtering gas. When the light-shielding film 40 is composed of a plurality of films with different compositions, the film formation process described above is performed a plurality of times while changing the composition and flow rate of the sputtering gas for each film formation process. When the light-shielding film 40 is composed of a single film whose composition changes continuously in the thickness direction, the film formation process described above is performed only once while changing the composition and flow rate of the sputtering gas.

The lower layer 31, the upper layer 32, and the light-shielding film 40 are preferably formed continuously by using an in-line sputtering apparatus without exposing the transparent substrate 20 to the atmosphere by removing the transparent substrate 20 from the apparatus. Unintended surface oxidation and surface carbonization of each layer can be prevented by continuously forming films without taking them out of the apparatus. Unintended surface oxidation or surface carbonization of each layer occurs when transferring a phase shift film pattern to a resist film formed on a display device substrate or a laser beam used when writing a resist film formed on the light shielding film 40. There is a possibility that the reflectance of the exposure light used for the etching may be changed, or the etching rate of the oxidized portion or the carbonized portion may be changed.

Since the phase shift mask blank 10 shown in FIG. 1 includes the light shielding film 40 on the phase shift film 30, a light shielding film forming step is performed when manufacturing the phase shift mask blank 10. When manufacturing a phase shift mask blank having no light shielding film 40 on 30, the light shielding film forming step is not performed. When manufacturing a phase shift mask blank having the light shielding film 40 on the phase shift film 30 and the resist film on the light shielding film 40, the resist film is formed on the light shielding film 40 after the light shielding film forming step. Furthermore, when manufacturing a phase shift mask blank having no light shielding film 40 on the phase shift film 30 and having a resist film on the phase shift film 30, the light shielding film forming step is not performed, and the phase shift film forming step is performed. A resist film is formed on the phase shift film 30 later.

In the phase shift mask blank 10 of Embodiment 1, the reflectance (rear surface reflectance) of the phase shift film 30 with respect to light in the wavelength range of 365 nm or more and 436 nm or less incident from the transparent substrate 20 side is more than 20%. By reducing the absorption of the exposure light in the phase shift film 30, positional change of the phase shift film pattern caused by thermal expansion of the phase shift film pattern can be suppressed. Further, in the phase shift mask blank 10 of Embodiment 1, the reflectance (back surface reflectance) of the phase shift film 30 with respect to light in the wavelength range of 365 nm to 436 nm incident from the transparent substrate 20 side has a fluctuation range of 10% or less. Therefore, when the exposure light is compound light containing light of a plurality of wavelengths selected from the wavelength range of 365 nm to 436 nm, the phase shift film 30 further reduces the absorption of the exposure light, thereby reducing the phase A position change of the phase shift film pattern due to thermal expansion of the shift film pattern can be suppressed. Moreover, the phase shift mask blank 10 of the first embodiment is made of a material that can be etched using the same etchant when the upper layer 32 and the lower layer 31 are patterned on the phase shift film 30, and the etching rate of the upper layer 32 is Since the ratio of the etching rate of the lower layer 31 to the lower layer 31 is more than 1 and 10 or less, a phase shift film pattern having a good cross-sectional shape and small CD variations can be formed by wet etching. Therefore, it is possible to obtain a phase shift mask blank capable of manufacturing a phase shift mask capable of accurately transferring a high-definition phase shift film pattern.

Embodiment 2.
Embodiment 2 describes a method of manufacturing a phase shift mask.

FIG. 2 is a schematic diagram showing a method of manufacturing a phase shift mask.
The phase shift mask manufacturing method shown in FIG. 2 is a phase shift mask blank manufacturing method using the phase shift mask blank 10 shown in FIG. It includes a pattern forming step, a phase shift film pattern forming step, a second resist pattern forming step, and a second light shielding film pattern forming step.
Each step will be described in detail below.

1. First Resist Pattern Forming Step In the first resist pattern forming step, first, a resist film is formed on the light shielding film 40 of the phase shift mask blank 10 of the first embodiment. The resist film material to be used is not particularly limited. Any material may be used as long as it is sensitive to a laser beam having a wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Moreover, the resist film may be either positive type or negative type.
After that, a predetermined pattern is drawn on the resist film using a laser beam having a wavelength selected from a wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is the pattern formed on the phase shift film.
After that, the resist film is developed with a predetermined developer to form a first resist pattern 50 on the light shielding film 40 .

2. First Light-Shielding Film Pattern Forming Step In the first light-shielding film pattern forming step, first, the light-shielding film 40 is etched using the first resist pattern 50 as a mask to form a first light-shielding film pattern 40a. The light shielding film 40 is made of, for example, a chromium-based material containing chromium (Cr). The etchant for etching the light shielding film 40 is not particularly limited as long as it can selectively etch the light shielding film 40 . Specifically, an etchant containing ceric ammonium nitrate and perchloric acid is mentioned.
After that, the first resist pattern 50 is stripped using a resist stripper or by ashing.

3. Phase Shift Film Pattern Forming Step In the first phase shift film pattern forming step, the phase shift film 30 is etched using the first light shielding film pattern 40a as a mask, and the phase shift film 30 composed of the upper layer pattern 32a and the lower layer pattern 31a is etched. A shift film pattern 30a is formed. The upper layer 32 and the lower layer 31 included in the phase shift film 30 are composed of materials that can be etched using the same etchant. Therefore, the upper layer 32 and the lower layer 31 can be etched with the same etchant. The etchant 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 etchant containing ammonium fluoride, phosphoric acid and hydrogen peroxide, and an etchant containing ammonium hydrogen fluoride and hydrogen peroxide can be used.

4. Second Resist Pattern Forming Step In the second resist pattern forming step, first, a resist film is formed to cover the first light shielding film pattern 40a. The resist film material to be used is not particularly limited. Any material may be used as long as it is sensitive to a laser beam having a wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Moreover, the resist film may be either positive type or negative type.
After that, a predetermined pattern is drawn on the resist film using a laser beam having a wavelength selected from a wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is a light shielding band pattern for shielding the peripheral region of the region where the pattern is formed on the phase shift film.
After that, the resist film is developed with a predetermined developer to form a second resist pattern 60 on the first light shielding film pattern 40a.

5. Second Light-Shielding Film Pattern Forming Step In the second light-shielding film pattern forming step, the first light-shielding film pattern 40a is etched using the second resist pattern 60 as a mask to form a second light-shielding film pattern 40b. . The first light shielding film pattern 40a is made of a chromium-based material containing chromium (Cr). The etchant for etching the first light shielding film pattern 40a is not particularly limited as long as it can selectively etch the first light shielding film pattern 40a. For example, an etchant containing ceric ammonium nitrate and perchloric acid may be used.
After that, the second resist pattern 60 is stripped using a resist stripper or by ashing.
Thus, a phase shift mask 100 is obtained.

Since the phase shift mask blank 10 shown in FIG. 1 has the light shielding film 40 on the phase shift film 30, when manufacturing a phase shift mask using the phase shift mask blank 10 shown in FIG. 1 resist pattern forming step, a first light shielding film pattern forming step, a phase shift film pattern forming step, a second resist pattern forming step, and a second light shielding film pattern forming step. When manufacturing a phase shift mask using a phase shift mask blank which does not have the light shielding film 40 on the film 30, a resist pattern forming step and a phase shift film pattern forming step are performed. Here, in the resist pattern forming process,
A resist pattern is formed on the phase shift film 30, and in the phase shift film pattern forming process, the phase shift film pattern is formed using the resist pattern as a mask.
Further, when manufacturing a phase shift mask using a phase shift mask blank having a light shielding film 40 on the phase shift film 30 and a resist film on the light shielding film 40, in the first resist pattern forming step, A process of forming a resist film on the light shielding film 40 is not required.
Furthermore, when manufacturing a phase shift mask using a phase shift mask blank which does not have the light shielding film 40 on the phase shift film 30 and has a resist film on the phase shift film 30, the above resist pattern forming step , the process of forming a resist film on the phase shift film 30 is not required.

According to the phase shift mask manufacturing method of the second embodiment, since the phase shift mask blank of the first embodiment is used, a phase shift film pattern with little positional change can be formed. In addition, a phase shift film pattern having a good cross-sectional shape and small CD variation can be formed. Therefore, it is possible to manufacture a phase shift mask capable of accurately transferring a fine phase shift film pattern.

Embodiment 3.
In Embodiment 3, a method for manufacturing a display device will be described. The display device is manufactured by performing the following mask placement process and pattern transfer process. The pattern transfer process corresponds to the pattern transfer method.
Each step will be described in detail below.

1. Mounting Step In the mounting step, the phase shift mask manufactured in the second embodiment is mounted on the mask stage of the exposure apparatus. Here, the phase shift mask is arranged so as to face the resist film formed on the display device substrate via the projection optical system of the exposure device. For example, as an exposure apparatus, a projection exposure apparatus having an equal-magnification projection optical system is used.

2. Pattern Transfer Process In the pattern transfer process, the phase shift mask is irradiated with exposure light to transfer the phase shift film pattern to the resist film formed on the display device substrate. The exposure light is compound light containing light of multiple wavelengths selected from a wavelength range of 313 nm to 436 nm. For example, the exposure light is compound light including i-line, h-line and g-line, or compound light including j-line, i-line, h-line and g-line. When compound light is used as the exposure light, the intensity of the exposure light can be increased and the throughput can be increased, so that the manufacturing cost of the display device can be reduced.

According to the manufacturing method of the display device of the third embodiment, since the phase shift mask manufactured in the second embodiment is used, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is reduced. A high-resolution and high-definition display device can be manufactured in which line-and-space patterns and hole patterns of 1.8 μm or less are transferred without causing CD errors.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples. The following examples are examples of the present invention and do not limit the present invention.

The phase shift mask blanks of Examples 1 to 6 and Comparative Example 1 include a transparent substrate, a phase shift film formed on the transparent substrate, and a light shielding film formed on the phase shift film. A synthetic quartz glass substrate having a size of 800 mm×920 mm and a thickness of 10 mm was used as the transparent substrate.
Examples 1 to 6 and Comparative Example 1 will be described in detail below.

Example 1.
The phase shift film in the phase shift mask blank of Example 1 is composed of a lower layer (MoSi, film thickness 10 nm) and an upper layer (MoSiN, film thickness 155 nm) arranged in order from the transparent substrate side.

Due to the two-layer structure, the phase shift film had a transmittance of 3.5% and a phase difference of 179.7° for light of 365 nm.
The transmittance and phase difference were measured using MPM-100 (trade name) manufactured by Lasertech. Examples 2 to 6 and Comparative Example 1 were also measured in the same manner.

The phase shift film had a rear surface reflectance of 43.0% at a wavelength of 365 nm, 42.2% at a wavelength of 405 nm, and 42.4% at a wavelength of 436 nm. In addition, the fluctuation width of the rear surface reflectance of the phase shift film in the wavelength region from 365 nm to 436 nm was 0.8%. Therefore, positional change of the phase shift film pattern due to thermal expansion of the phase shift film can be suppressed.
The back surface reflectance was measured using SolidSpec-3700 (trade name) manufactured by Shimadzu Corporation. Examples 2 to 6 and Comparative Example 1 were also measured in the same manner. Also, the fluctuation width of the back surface reflectance was calculated from the measurement result of the back surface reflectance. It was calculated in the same manner in Examples 2-6.

When an etchant containing ammonium hydrogen fluoride and hydrogen peroxide was used, the ratio of the etch rate of the lower layer to the etch rate of the upper layer was 1.7. Therefore, the cross-sectional shape of the phase shift film pattern after wet etching is good, and the CD variation is reduced.
The etching rate of the phase shift film in the etching solution containing ammonium hydrogen fluoride and hydrogen peroxide was 0.07 nm/sec.

A phase shift mask blank of Example 1 was manufactured by the following method.
First, a synthetic quartz glass substrate, which is a transparent substrate, was prepared. Both main surfaces of the transparent substrate are mirror-polished. Both main surfaces of the transparent substrates prepared in Examples 2 to 6 and Comparative Example 1 were similarly mirror-polished.
After that, the transparent substrate was loaded into an in-line sputtering apparatus. An in-line sputtering apparatus is provided with a sputtering chamber. A MoSi target and a Cr target are placed in the sputtering chamber.
After that, a MoSi target (Mo:Si=1:4) placed in the sputtering chamber was applied with a sputtering power of 5.0 kW, and Ar gas was introduced into the sputtering chamber at a flow rate of 100 sccm. When the transparent substrate passed near the MoSi target, a lower layer made of MoSi and having a thickness of 10 nm was formed on the main surface of the transparent substrate.
After that, a sputtering power of 7.0 kW was applied to the MoSi target arranged in the sputtering chamber, and a mixed gas of Ar gas and N2 gas was mixed in the sputtering chamber so that the flow rate of Ar gas was 100 sccm and the flow rate of N2 gas was 60 sccm. The transparent substrate was transported while introducing the When the transparent substrate passed near the MoSi target, an upper layer made of MoSiN and having a thickness of 155 nm was formed on the lower layer.
Thereafter, a sputtering power of 8.6 kW was applied to the Cr target, and a mixed gas of Ar gas and CO2 gas was introduced into the sputtering chamber so that the flow rates of Ar gas and CO2 gas were 100 sccm and 20 sccm, respectively. was transported.
After that, a transparent substrate having a phase shift film composed of a lower layer (MoSi, film thickness 10 nm) and an upper layer (MoSiN, film thickness 155 nm) and a light shielding film (CrOC, film thickness 130 nm) was formed by an in-line sputtering apparatus. Removed from and washed.
The formation of the lower layer, the upper layer, and the light-shielding film were performed continuously in the in-line sputtering apparatus without exposing the transparent substrate to the atmosphere by taking it out of the in-line sputtering apparatus.

A phase shift mask was manufactured by the following method using the phase shift mask blank described above.
First, on the light-shielding film of the phase shift mask blank described above, a resist film made of novolac-based positive photoresist was formed.
After that, a 1.8 μm line-and-space pattern was drawn on the resist film using a laser beam with a wavelength of 413 nm using a laser drawing machine.
After that, the resist film was developed with a predetermined developer to form a first resist pattern on the light shielding film.
After that, the light shielding film was etched using the first resist pattern as a mask to form a first light shielding film pattern. An etchant containing ceric ammonium nitrate and perchloric acid was used as an etchant for etching the light-shielding film.
After that, the first resist pattern was stripped using a resist stripper.
Thereafter, the phase shift film was etched using the first light shielding film pattern as a mask to form a phase shift film pattern. An etchant containing ammonium hydrogen fluoride and hydrogen peroxide was used as an etchant for etching the phase shift film.
After that, a resist film made of novolac-based positive photoresist was formed to cover the first light-shielding film pattern.
After that, a predetermined pattern was drawn on the resist film using a laser beam with a wavelength of 413 nm using a laser drawing machine.
After that, the resist film was developed with a predetermined developer to form a second resist pattern on the first light-shielding film pattern.
Thereafter, the first light shielding film pattern was etched using the second resist pattern as a mask to form a second light shielding film pattern. As an etchant for etching the first light shielding film pattern, an etchant containing ceric ammonium nitrate and perchloric acid was used.

In the cross section of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above, a slight erosion occurs at the boundary between the upper layer and the lower layer in the film thickness direction of the phase shift film pattern. It was to the extent that it did not affect the mask characteristics.
The cross section of the phase shift film pattern of the phase shift mask was observed using an electron microscope (JSM7401F (trade name) manufactured by JEOL Ltd.). Similar observations were made in Examples 2 to 6 and Comparative Example 1.

The CD variation of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above was 50 nm, which was good. The CD variation is the width of deviation from the target line-and-space pattern (width of line pattern: 1.8 μm, width of space pattern: 1.8 μm).
The CD variation of the phase shift film pattern of the phase shift mask was measured using SIR8000 manufactured by Seiko Instruments Nanotechnology. Examples 2 to 6 and Comparative Example 1 were also measured in the same manner.

In the phase shift mask described above, the positional change of the phase shift film pattern is small, and the phase shift film pattern has an excellent pattern cross-sectional shape and excellent CD uniformity. In addition, since this phase shift mask has excellent optical properties (back surface reflectance, fluctuation range of back surface reflectance, transmittance, phase difference), misalignment during pattern transfer is suppressed and display It was confirmed that the resolution of the transfer pattern transferred onto the device substrate was improved, and that a line-and-space pattern with a pattern line width of 1.8 μm was transferred without CD error.
The pattern transfer using the phase shift mask was performed by a projection exposure method using an equal-magnification projection optical system. The exposure light was compound light including i-line, h-line and g-line. In Examples 2 to 6, the same procedure was carried out.

Example 2.
The phase shift film in the phase shift mask blank of Example 2 is composed of a lower layer (MoSi, film thickness 3 nm) and an upper layer (ZrSiN, film thickness 75 nm) arranged in order from the transparent substrate side. In Example 2, since the lower layer MoSi has a high etching rate, the upper layer contains Zr to increase the etching rate.

Due to the two-layer structure, the phase shift film had a transmittance of 3.1% and a phase difference of 177.4° for light of 365 nm.

The phase shift film had a rear surface reflectance of 41.5% at a wavelength of 365 nm, 41.2% at a wavelength of 405 nm, and 38.3% at a wavelength of 436 nm. In addition, the fluctuation width of the rear surface reflectance of the phase shift film in the wavelength region from 365 nm to 436 nm was 3.2%. Therefore, positional change of the phase shift film pattern due to thermal expansion of the phase shift film can be suppressed.

When an etchant containing ammonium hydrogen fluoride and hydrogen peroxide was used, the ratio of the etch rate of the lower layer to the etch rate of the upper layer was 1.9. Therefore, the cross-sectional shape of the phase shift film pattern after wet etching is good, and the CD variation is reduced.
The etching rate of the phase shift film in the etching solution containing ammonium hydrogen fluoride and hydrogen peroxide was 0.26 nm/sec.

A phase shift mask blank of Example 2 was manufactured in the same manner as in Example 1, except for the step of forming a phase shift film. The deposition process of the phase shift film of Example 2 is as follows.
First, a transparent substrate was loaded into an in-line sputtering apparatus. An in-line sputtering apparatus is provided with a sputtering chamber. A MoSi target (Mo:Si=1:4), a ZrSi target (Zr:Si=1:2), and a Cr target are arranged in the sputtering chamber.
After that, a sputtering power of 3.0 kW was applied to the MoSi target arranged in the sputtering chamber, and the transparent substrate was transported while Ar gas was introduced into the sputtering chamber at a flow rate of 55 sccm. When the transparent substrate passed near the MoSi target, a lower layer made of MoSi and having a thickness of 3 nm was formed on the main surface of the transparent substrate.
After that, a sputtering power of 5.6 kW was applied to the ZrSi target arranged in the sputtering chamber, and a mixed gas of Ar gas and N2 gas was added to the sputtering chamber so that the flow rate of Ar gas was 50 sccm and the flow rate of N2 gas was 40 sccm. The transparent substrate was transported while introducing the When the transparent substrate passed near the ZrSi target, an upper layer made of ZrSiN and having a thickness of 75 nm was formed on the lower layer.

A phase shift mask was manufactured in the same manner as in Example 1 using the phase shift mask blank described above.

In the cross section of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above, slight erosion occurs at the boundary between the upper layer and the lower layer in the film thickness direction of the phase shift film pattern, but the mask It was the extent which does not affect the characteristic.

The CD variation of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above was 45 nm, which was good.

In the phase shift mask described above, the positional change of the phase shift film pattern is small, and the phase shift film pattern has an excellent pattern cross-sectional shape and excellent CD uniformity. In addition, this phase shift mask has excellent optical properties (rear surface reflectance, variation range of rear surface reflectance, transmittance, phase difference), which suppresses misregistration during pattern transfer. It was confirmed that the resolution of the transfer pattern transferred onto the display device substrate was improved, and that a line-and-space pattern with a pattern line width of 1.8 μm was transferred without causing a CD error.

Example 3.
The phase shift film in the phase shift mask blank of Example 3 is composed of a lower layer (MoSi, film thickness 10 nm) and an upper layer (TiO2, film thickness 110 nm) arranged in order from the transparent substrate side. In Example 3, since the lower layer MoSi has a high etching rate, the upper layer is made of a material containing Ti to increase the etching rate.

Due to the two-layer structure, the phase shift film had a transmittance of 13.8% and a phase difference of 185.0° for light of 365 nm.

The phase shift film had a rear surface reflectance of 47.6% at a wavelength of 365 nm, 52.2% at a wavelength of 405 nm, and 53.6% at a wavelength of 436 nm. In addition, the fluctuation width of the rear surface reflectance of the phase shift film in the wavelength range from 365 nm to 436 nm was 6.0%. Therefore, positional change of the phase shift film pattern due to thermal expansion of the phase shift film can be suppressed.

When an etchant containing ammonium hydrogen fluoride and hydrogen peroxide was used, the ratio of the etch rate of the lower layer to the etch rate of the upper layer was 1.7. Therefore, the cross-sectional shape of the phase shift film pattern after wet etching is good, and the CD variation is reduced.
The etching rate of the phase shift film in the etching solution containing ammonium hydrogen fluoride and hydrogen peroxide was 0.15 nm/sec.

A phase shift mask blank of Example 3 was manufactured in the same manner as in Example 1, except for the step of forming a phase shift film. The deposition process of the phase shift film of Example 3 is as follows.
First, a transparent substrate was loaded into an in-line sputtering apparatus. An in-line sputtering apparatus is provided with a sputtering chamber. A MoSi target (Mo:Si=1:4), a Ti target and a Cr target are arranged in the sputtering chamber.
After that, a sputtering power of 5.5 kW was applied to the MoSi target arranged in the sputtering chamber, and the transparent substrate was transported while Ar gas was introduced into the sputtering chamber at a flow rate of 75 sccm. When the transparent substrate passed near the MoSi target, a lower layer made of MoSi and having a thickness of 3 nm was formed on the main surface of the transparent substrate.
After that, a sputtering power of 7.5 kW was applied to the Ti target placed in the sputtering chamber, and a mixed gas of Ar gas and O gas was added to the sputtering chamber so that the flow rate of Ar gas was 45 sccm and the flow rate of O gas was 35 sccm. The transparent substrate was transported while introducing the When the transparent substrate passed near the Ti target, an upper layer made of TiO2 and having a thickness of 200 nm was formed on the lower layer.

A phase shift mask was manufactured in the same manner as in Example 1 using the phase shift mask blank described above.

In the cross section of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above, slight erosion occurs at the boundary between the upper layer and the lower layer in the film thickness direction of the phase shift film pattern, but the mask It was the extent which does not affect the characteristic.

The CD variation of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above was 55 nm, which was good.

In the phase shift mask described above, the positional change of the phase shift film pattern is small, and the phase shift film pattern has an excellent pattern cross-sectional shape and excellent CD uniformity. In addition, this phase shift mask has excellent optical properties (rear surface reflectance, variation range of rear surface reflectance, transmittance, phase difference), which suppresses misregistration during pattern transfer. It was confirmed that the resolution of the transfer pattern transferred onto the display device substrate was improved, and that a line-and-space pattern with a pattern line width of 1.8 μm was transferred without causing a CD error.

Example 4.
The phase shift film in the phase shift mask blank of Example 4 is composed of a lower layer (ZrSi, film thickness 18 nm) and an upper layer (ZrSiON, film thickness 17 nm) arranged in order from the transparent substrate side. In Example 4, since the etching rate of ZrSi in the lower layer is high, the upper layer contains Zr to increase the etching rate.

Due to the above two-layer structure, the phase shift film had a transmittance of 6.4% and a phase difference of 185.9° for light of 365 nm.

The phase shift film had a rear surface reflectance of 50.8% at a wavelength of 365 nm, 55.2% at a wavelength of 405 nm, and 57.6% at a wavelength of 436 nm. Moreover, the fluctuation width of the rear surface reflectance of the phase shift film in the wavelength region from 365 nm to 436 nm was 6.8%. Therefore, positional change of the phase shift film pattern due to thermal expansion of the phase shift film can be suppressed.

When an etchant containing ammonium hydrogen fluoride and hydrogen peroxide was used, the ratio of the etch rate of the lower layer to the etch rate of the upper layer was 2.0. Therefore, the cross-sectional shape of the phase shift film pattern after wet etching is good, and the CD variation is reduced.
The etching rate of the phase shift film in the etching solution containing ammonium hydrogen fluoride and hydrogen peroxide was 0.44 nm/sec.

A phase shift mask blank of Example 4 was manufactured in the same manner as in Example 1, except for the step of forming a phase shift film. The deposition process of the phase shift film of Example 4 is as follows.
First, a transparent substrate was loaded into an in-line sputtering apparatus. An in-line sputtering apparatus is provided with a sputtering chamber. A ZrSi target (Zr:Si=1:2) and a Cr target are placed in the sputtering chamber.
After that, a sputtering power of 3.0 kW was applied to the ZrSi target arranged in the sputtering chamber, and the transparent substrate was transported while Ar gas was introduced into the sputtering chamber at a flow rate of 130 sccm. When the transparent substrate passed near the ZrSi target, a lower layer of ZrSi with a thickness of 18 nm was formed on the main surface of the transparent substrate.
After that, a sputtering power of 5.6 kW was applied to the ZrSi target arranged in the sputtering chamber, and a mixed gas of Ar gas, O gas and N gas was mixed at 100 sccm for Ar gas, 60 sccm for O gas and 40 sccm for N gas. The transparent substrate was transported while being introduced into the sputtering chamber so as to maintain the flow rate. When the transparent substrate passed near the ZrSi target, an upper layer made of ZrSiON and having a thickness of 117 nm was formed on the lower layer.

A phase shift mask was manufactured in the same manner as in Example 1 using the phase shift mask blank described above.

In the cross section of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above, slight erosion occurs at the boundary between the upper layer and the lower layer in the film thickness direction of the phase shift film pattern, but the mask It was the extent which does not affect the characteristic.

The CD variation of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above was 45 nm, which was good.

In the phase shift mask described above, the positional change of the phase shift film pattern is small, and the phase shift film pattern has an excellent pattern cross-sectional shape and excellent CD uniformity. In addition, this phase shift mask has excellent optical properties (rear surface reflectance, variation range of rear surface reflectance, transmittance, phase difference), which suppresses misregistration during pattern transfer. It was confirmed that the resolution of the transfer pattern transferred onto the display device substrate was improved, and that a line-and-space pattern with a pattern line width of 1.8 μm was transferred without causing a CD error.

Example 5.
In Example 5, a TiO2--SiO2 glass substrate was used as the transparent substrate. Therefore, positional change of the phase shift film pattern due to thermal deformation of the transparent substrate can be suppressed. The points other than the transparent substrate are the same as those of the first embodiment.

In the phase shift mask of Example 5, the positional change of the phase shift film pattern is smaller than that of Example 1, and the phase shift film pattern has an excellent pattern cross-sectional shape and excellent CD uniformity. The effect is equal to or greater than that of the shift mask.

Example 6.
In Example 6, a TiO2--SiO2 glass substrate was used as the transparent substrate. Therefore, positional change of the phase shift film pattern due to thermal deformation of the transparent substrate can be suppressed. The points other than the transparent substrate are the same as those of the fourth embodiment.

In the phase shift mask of Example 6, the positional change of the phase shift film pattern is smaller than that of Example 4, and the phase shift film pattern has an excellent pattern cross-sectional shape and excellent CD uniformity. The effect is equal to or greater than that of the shift mask.

Comparative example 1.
The phase shift film in the phase shift mask blank of Comparative Example 1 is composed of a MoSiON single layer film (thickness: 130 nm) arranged on a transparent substrate. The points other than the phase shift film are the same as those of the first embodiment.

The phase shift film had a transmittance of 7.5% and a phase difference of 180° for light of 365 nm.

The phase shift film had a rear surface reflectance of 12.5% at a wavelength of 365 nm, 10.6% at a wavelength of 405 nm, and 11.0% at a wavelength of 436 nm.

The etching rate of the phase shift film in the etchant containing ammonium hydrogen fluoride and hydrogen peroxide was 0.03 nm/sec.

A phase shift mask blank of Comparative Example 1 was manufactured in the same manner as in Example 1, except for the step of forming the phase shift film. The deposition process of the phase shift film of Comparative Example 1 is as follows.
First, a transparent substrate was loaded into an in-line sputtering apparatus. An in-line sputtering apparatus is provided with a sputtering chamber. A MoSi target (Mo:Si=1:4) and a Cr target are placed in the sputtering chamber.
After that, a sputtering power of 5.4 kW was applied to the MoSi target placed in the sputtering chamber, and a mixed gas of Ar gas and NO gas was added to the sputtering chamber so that the flow rate of the Ar gas was 50 sccm and the flow rate of the NO gas was 40 sccm. The transparent substrate was transported while introducing the When the transparent substrate passed near the MoSi target, a single-layer phase shift film made of MoSiON and having a thickness of 130 nm was formed on the main surface of the transparent substrate.

A phase shift mask was manufactured in the same manner as in Example 1 using the phase shift mask blank described above.

The cross-section of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above is tapered, and has not reached a level at which a high-definition phase shift film pattern can be transferred with high accuracy.

The CD variation of the phase shift film pattern of the phase shift mask manufactured using the phase shift mask blank described above was 100 nm, which did not reach a level at which a high-definition phase shift film pattern could be transferred with high accuracy.

In the phase shift mask described above, the positional change of the phase shift film pattern is large, and the phase shift film pattern has insufficient pattern cross-sectional shape and CD uniformity. Therefore, it is difficult to accurately transfer a fine phase shift film pattern using the phase shift mask described above.

As described above, the present invention has been described in detail based on the embodiments and examples, but the present invention is not limited thereto. It is obvious that those skilled in the art can make modifications and improvements within the technical spirit of the present invention.

The same effects as those of the present invention can be obtained with the invention having the following configuration.

(Configuration A-1)
A phase shift mask blank for manufacturing a phase shift mask for manufacturing a display device having a phase shift film pattern on a transparent substrate by wet etching,
comprising a transparent substrate and a phase shift film formed on the transparent substrate;
The phase shift film includes a lower layer having a function of adjusting reflectance with respect to light incident from the transparent substrate side, and an upper layer disposed above the lower layer and having a function of adjusting transmittance and phase difference with respect to exposure light. and at least
The phase shift film has a transmittance of 1% or more and 50% or less for light with a wavelength of 365 nm contained in the exposure light, and a phase difference of 160° or more and 200° or less,
The phase shift film has a reflectance of more than 20% for light in a wavelength range of 365 nm to 436 nm incident from the transparent substrate side,
the upper layer is composed of a material containing metal and one or both of oxygen and nitrogen;
The lower layer is made of a material containing a metal,
The upper layer and the lower layer are made of a material that can be etched using the same etchant when patterning the phase shift film, and the ratio of the etching rate of the lower layer to the etching rate of the upper layer is more than 1 and 10 or less. A phase shift mask blank characterized by:

(Configuration A-2)
The phase shift mask blank according to structure A-1, wherein the phase shift film has an etching rate of 0.06 nm/sec or more and 2.5 nm/sec or less in the etchant.

(Configuration A-3)
Materials constituting the upper layer include a material consisting of metal and oxygen, a material consisting of metal and nitrogen, a material consisting of metal, oxygen and nitrogen, a material consisting of metal, silicon and oxygen, and a material consisting of metal, silicon and nitrogen. and a material consisting of metal, silicon, oxygen and nitrogen, and a component that speeds up or slows down the etching rate of the upper layer in an etchant used when patterning the phase shift film on these materials The phase-shift mask blank of arrangement A-1 or A-2, wherein the phase-shift mask blank is selected from materials added with

(Configuration A-4)
The material constituting the lower layer is a material made of metal, a material made of metal and silicon, and an etchant used for patterning the phase shift film on these materials to increase the etching rate of the lower layer. A phase-shifting mask blank according to arrangement A-1 or A-2, characterized in that it is selected from materials plus a component or a retarding component.

(Configuration A-5)
From Configuration A-1, wherein the metal contained in the material constituting the upper layer and the metal contained in the material constituting the lower layer are each at least one selected from titanium, zirconium, molybdenum and tantalum. The phase shift mask blank according to any one of A-4.

(Configuration A-6)
The phase shift mask blank according to any one of structures A-1 to A-5, wherein the metal contained in the material forming the upper layer is at least one selected from titanium and zirconium.

(Configuration A-7)
The phase shift mask blank according to Structure A-4, wherein the metal contained in the material forming the lower layer is molybdenum, and the component that slows down the etching rate of the lower layer is carbon.

(Configuration A-8)
The phase shift mask blank according to any one of Structures A-1 to A-7, wherein the transparent substrate is made of SiO2-TiO2 based glass.

(Configuration A-9)
The phase shift mask blank according to any one of Structures A-1 to A-8, further comprising a light shielding film formed on the phase shift film.

(Configuration A-10)
In a method for manufacturing a phase shift mask for manufacturing a display device,
a resist pattern forming step of forming a resist pattern on the phase shift film of the phase shift mask blank according to any one of configurations A-1 to A-8;
and a phase shift film pattern forming step of forming a phase shift film pattern by wet-etching the phase shift film using the resist pattern as a mask.

(Configuration A-11)
In a method for manufacturing a phase shift mask for manufacturing a display device,
a resist pattern forming step of forming a resist pattern on the light shielding film of the phase shift mask blank according to configuration A-9;
a light-shielding film pattern forming step of forming a light-shielding film pattern by wet-etching the light-shielding film using the resist pattern as a mask;
and a phase shift film pattern forming step of forming a phase shift film pattern by wet-etching the phase shift film using the light shielding film pattern as a mask.

10 phase shift mask blank 20 transparent substrate 30 phase shift film 30a phase shift film pattern 31 lower layer 31a lower layer pattern 32 upper layer 32a upper layer pattern 40 light shielding film 40a first light shielding film pattern 40b second second , 50 first resist pattern, 60 second resist pattern, 100 phase shift mask.

Claims (15)

A phase shift mask blank for manufacturing a phase shift mask for manufacturing a display device having a phase shift film pattern on a transparent substrate,
comprising a transparent substrate and a phase shift film formed on the transparent substrate;
The phase shift film includes a lower layer having a function of adjusting reflectance with respect to light incident from the transparent substrate side, and an upper layer disposed above the lower layer and having a function of adjusting transmittance and phase difference with respect to exposure light. and at least
The phase shift film has a predetermined optical characteristic of transmittance and phase difference with respect to exposure light,
The phase shift film has a back surface reflectance of more than 20% with respect to light in the wavelength range of 365 nm to 436 nm incident from the transparent substrate side, and is resistant to light in the wavelength range of 365 nm to 436 nm incident from the transparent substrate side. A phase shift mask blank, wherein the difference between the maximum value and the minimum value of the back surface reflectance is 10% or less. 2. The phase shift film according to claim 1, wherein the phase shift film has a transmittance of 1% or more and 50% or less and a phase difference of 160° or more and 200° or less with respect to light having a wavelength of 365 nm contained in the exposure light. mask blank. the upper layer is composed of a material containing metal and one or both of oxygen and nitrogen;
The lower layer is made of a material containing a metal,
The upper layer and the lower layer are made of a material that can be etched using the same etchant when patterning the phase shift film, and the ratio of the etching rate of the lower layer to the etching rate of the upper layer is more than 1 and 10 or less. 3. The phase shift mask blank according to claim 1 or 2, characterized in that: 4. The phase shift mask blank according to claim 3, wherein said phase shift film has an etching rate of 0.06 nm/sec or more and 2.5 nm/sec or less in said etchant. Materials constituting the upper layer include a material consisting of metal and oxygen, a material consisting of metal and nitrogen, a material consisting of metal, oxygen and nitrogen, a material consisting of metal, silicon and oxygen, and a material consisting of metal, silicon and nitrogen. and a material consisting of metal, silicon, oxygen and nitrogen, and a component that speeds up or slows down the etching rate of the upper layer in an etchant used when patterning the phase shift film on these materials 5. A phase shift mask blank according to any one of claims 1 to 4, characterized in that it is selected from materials with added The material constituting the lower layer is a material made of metal, a material made of metal and silicon, and an etchant used for patterning the phase shift film on these materials to increase the etching rate of the lower layer. 5. A phase-shifting mask blank according to any one of claims 1 to 4, characterized in that it is selected from materials with added components or retarding components. 7. Each of the metal contained in the material forming the upper layer and the metal contained in the material forming the lower layer is at least one selected from titanium, zirconium, molybdenum and tantalum. The phase shift mask blank according to any one of Claims 1 to 3. 8. The phase shift mask blank according to any one of claims 3 to 7, wherein the metal contained in the material forming the upper layer is at least one selected from titanium and zirconium. 7. The phase shift mask blank according to claim 6, wherein the metal contained in the material forming the lower layer is molybdenum, and the component that slows down the etching rate of the lower layer is carbon. 10. The phase shift mask blank according to any one of claims 1 to 9, wherein the transparent substrate is made of _SiO2 - _TiO2 based glass. 11. The phase shift mask blank according to any one of claims 1 to 10, further comprising a light shielding film formed on the phase shift film. In a method for manufacturing a phase shift mask for manufacturing a display device,
A resist pattern forming step of forming a resist pattern on the phase shift film of the phase shift mask blank according to any one of claims 1 to 10;
and a phase shift film pattern forming step of forming a phase shift film pattern by wet-etching the phase shift film using the resist pattern as a mask. In a method for manufacturing a phase shift mask for manufacturing a display device,
a resist pattern forming step of forming a resist pattern on the light shielding film of the phase shift mask blank according to claim 11;
a light-shielding film pattern forming step of forming a light-shielding film pattern by wet-etching the light-shielding film using the resist pattern as a mask;
and a phase shift film pattern forming step of forming a phase shift film pattern by wet-etching the phase shift film using the light shielding film pattern as a mask. 14. A pattern transfer method, comprising irradiating the phase shift mask obtained by the phase shift mask manufacturing method according to claim 12 or 13 with exposure light to transfer the pattern onto a display device substrate. 15. A pattern transfer method according to claim 14, wherein said exposure light is compound light containing light of a plurality of wavelengths selected from a wavelength range of 365 nm to 436 nm.

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