JP2018116269A - Phase shift mask blank for manufacturing display device, method for manufacturing phase shift mask for manufacturing display device, and method for manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase shift mask blank for manufacturing a display device, which includes a novel phase shift mask having a remarkable property in wavelength dependency of transmittance.SOLUTION: The phase shift mask blank includes a transparent substrate and a phase shift film 30 formed on the transparent substrate. The phase shift film has at least a phase shift layer 31 having a function of adjusting a transmittance and a phase difference with respect to exposure light, and a metal layer 33 having a function of adjusting wavelength dependency of the transmittance in the wavelength range from 365 nm to 436 nm. The phase shift layer is formed of a material comprising metal, silicon and at least one element of nitrogen and oxygen; and the metal layer is formed of a material comprising metal or a material comprising a metal compound constituted by metal and at least one of carbon, fluorine, nitrogen and oxygen and having a content percentage of the metal of 55 atomic% or more and less than 100 atomic%. The wavelength dependency of transmittance of the phase shift film in the wavelength range from 365 nm to 436 nm is within 5.5%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a phase shift mask blank for manufacturing a display device, a method for manufacturing a phase shift mask for manufacturing a display device, and a method for manufacturing a display device.

  When manufacturing a liquid crystal display device or an organic EL display device, a semiconductor element such as a transistor is formed by stacking a plurality of conductive films and insulating films which have been subjected to necessary patterning. At that time, a photolithography process is often used for patterning of individual films to be stacked. For example, some thin film transistors and LSIs used in these display devices have a configuration in which a contact hole is formed in an insulating layer by a photolithography process and an upper layer pattern and a lower layer pattern are electrically connected. Recently, in such a display device, there is an increasing need to display a bright and fine image with sufficient operation speed and to reduce power consumption. In order to satisfy such a demand, it is required to miniaturize and highly integrate the constituent elements of the display device. For example, it is desired to reduce the diameter of the contact hole from 3 μm to 2.5 μm, 2 μm, 1.8 μm, and 1.5 μm. For example, it is desired to reduce the pitch width of the line and space pattern from 3 μm to 2.5 μm, 2 μm, 1.8 μm, and 1.5 μm.

  From such a background, a photomask for manufacturing a display device that can cope with the miniaturization of line and space patterns and contact holes is desired.

  In realizing the miniaturization of line and space patterns and contact holes, the resolution limit of an exposure device for manufacturing a display device is 3 μm in a conventional photomask, so that there is no sufficient process margin (Process Margin). Products with a minimum line width close to the resolution limit must be produced. For this reason, there has been a problem that the defect rate of the display device becomes high.

  For example, when a photomask having a hole pattern for forming contact holes is used and transferred to a transfer target, if the hole pattern has a diameter exceeding 3 μm, transfer is performed using a conventional photomask. I was able to. However, it has been very difficult to transfer a hole pattern having a diameter of 3 μm or less, particularly a hole pattern having a diameter of 2.5 μm or less. In order to transfer a hole pattern having a diameter of 2.5 μm or less, for example, it may be possible to switch to an exposure machine having a high NA, but a large investment is required.

  Therefore, in order to improve the resolution and cope with the miniaturization of the line and space pattern and the contact hole, a phase shift mask has attracted attention as a photomask for manufacturing a display device.

For example, Patent Document 1 proposes a phase shift mask blank for a display device including a phase shift film having a configuration in which two or more thin films are stacked on a transparent substrate. The thin films constituting the phase shift film have different compositions, but both are made of materials that can be etched by the same etching solution, and have different etching rates due to different compositions. In Patent Document 1, the etching rate of each thin film constituting the phase shift film is adjusted so that the cross-sectional inclination of the edge portion of the phase shift film pattern is formed at a steep angle (steep slope) during patterning of the phase shift film. ing.
The phase shift film specifically described in Patent Document 1 is a chromium phase shift film having a structure in which three, five, or six layers of chromium carbon oxynitride (CrCON) having different compositions are laminated. is there.

Patent Document 2 describes a phase inversion blank mask for FPD in which a phase inversion film, a metal film used as an etching mask for the phase inversion film, and a resist film are sequentially laminated on a transparent substrate. Here, the phase inversion film is made of, for example, one of MoSi, MoSiO, MoSiN, MoSiC, MoSiCO, MoSiON, MoSiCN, and MoSiCON, and the metal film (etching mask film) has an etching selectivity with the phase inversion film. It is described that it consists of one of the materials, for example, Cr, CrO, CrN, CrC, CrCO, CrON, CrCN, CrCON.
In Patent Document 2, the phase inversion film has a transmittance of 1% to 40%, preferably a transmittance of 5% to 20%, and a transmittance of 10% or less with respect to exposure light having a composite wavelength. It is described that it is desirable to have a deviation. In addition, it is described that the phase inversion film preferably has a reflectance of 30% or less, desirably 15% or less, and a reflectance deviation of 10% or less with respect to exposure light having a composite wavelength. (Here, the deviation refers to the difference between the maximum value and the minimum value among the transmittance and reflectance values of i-line, h-line, and g-line exposure light.)
However, Patent Document 2 does not describe an example in which specific phase inversion films and metal films (etching mask films) for satisfying these optical characteristics are specified.

Such a phase shift mask receives exposure light of various wavelengths output from various exposure machines.
For example, in the case of a phase shift mask for manufacturing a display device, as an exposure machine used in the process of transferring a mask pattern, for example, peak intensities for i-line (365 nm), h-line (405 nm) and g-line (436 nm), respectively. There is known a light source (ultra-high pressure UV lamp) that outputs composite light having a light source. For example, if the composite light is used as exposure light when a mask pattern of a phase shift mask is transferred onto the main surface of a mother glass substrate whose size is increasing with the recent increase in size of display devices, the amount of light can be reduced. It is possible to earn and to shorten the tact time.

Korean Registered Patent No. 1282040 Korean Registered Patent No. 1624995

First, in the phase shift mask for display device and the phase shift mask blank, “a transmittance fluctuation range (amount of change) in a wavelength range of 365 nm to 436 nm (appropriately referred to as a predetermined transmittance wavelength dependency)”. A small (for example, within 5.5%) phase shift film is basically very difficult to realize (Problem 1). The reason for this is that the composition and thickness of each layer constituting the phase shift film is adjusted to satisfy the essential optical characteristics (phase difference and transmittance) (this is given priority), and accordingly the transmittance of the phase shift film is adjusted. This is because the wavelength dependency is determined, so that only the transmittance wavelength dependency cannot be independently and freely controlled (independently adjusted to a desired value). For this reason, no actual measured values of transmittance and reflectance have been reported for specific examples in which the layer structure of the phase shift film and the material of each layer are specifically specified.
In view of the above problem 1, it is desired to provide a new phase shift film excellent in transmittance wavelength dependency.

  Furthermore, for example, a specific example in which the predetermined transmittance wavelength dependency is smaller than 1.0% and the transmittance wavelength dependency is particularly excellent has not been reported (Problem 2).

Secondly, the phase shift film used in the phase shift mask for a display device conventionally proposed in Patent Document 1 described above is a laser drawing light used when patterning a resist film used for forming a phase shift film pattern. It is not designed in consideration of the influence on the resist film due to the reflection of light. For this reason, the surface reflectance of the phase shift film with respect to laser drawing light (usually one wavelength within a wavelength range of 350 nm to 436 nm) exceeds 20%. As a result, a standing wave is generated in the resist film, and the roughness of the edge portion of the resist film pattern is deteriorated. Accordingly, there is a problem that the roughness of the edge portion of the phase shift film pattern is deteriorated.
In the above-mentioned Patent Document 2, it is described that the phase inversion film has a reflectance of 30% or less, preferably 15% or less, with respect to the exposure light of the composite wavelength, but a film for realizing it. No specific examples of the configuration and film material have been reported.
The surface reflectivity at the wavelength of the laser drawing light is ideally 10% or less, and further 5% or less. However, the surface reflectivity should be 10% or less while satisfying various optical characteristics. Is actually very difficult.
Specifically, in the case of a light-shielding film, it is only necessary to satisfy the light-shielding property (optical density). Therefore, it is relatively easy to provide an antireflection layer and add surface reflectance characteristics. On the other hand, in the case of a phase shift film, the phase difference and the transmittance also fluctuate by providing an antireflection layer. Therefore, the film design combines the characteristics of the surface reflectance with satisfying the phase difference and the transmittance. It is not easy to do. Therefore, in addition to the phase difference and the transmittance, it is not easier to combine the characteristics of the surface reflectance while satisfying the transmittance wavelength dependency (Problem 3).
Note that Patent Document 2 does not describe values obtained by actually measuring the transmittance and the reflectivity of a specific example in which the material of the phase inversion film and the metal film (etching mask film) is specifically specified. Furthermore, it is desired to exceed the reflectance level (for example, “15% or less”) described in Patent Document 2. Specifically, for example, no specific example has been reported in which the reflectance in the wavelength range of 365 nm to 436 nm is 10% or less, or the reflectance in the wavelength range of 350 nm to 436 nm is 15% or less.

Further, the phase shift film used for the phase shift mask for the display device conventionally proposed in the above-mentioned Patent Documents 1 and 2 is not designed in consideration of the back surface reflectance in the wavelength range of 365 nm to 436 nm.
For this reason, when the back surface reflectance is relatively low, there is a risk of pattern displacement due to thermal expansion due to heat absorption of exposure light by the film.
Therefore, it is not easy for the phase shift film to have the characteristics of the back surface reflectance while satisfying predetermined transmittance wavelength dependency in addition to the phase difference and the transmittance (Problem 4).

The first object of the present invention is to provide a new phase shift film excellent in transmittance wavelength dependency with respect to the above-described problem 1.
The second object of the present invention is to provide a new phase shift film which is excellent in transmittance wavelength dependency and excellent in other characteristics with respect to the above-described problem 1.
The third object of the present invention is to provide a new phase shift film that is exceptionally excellent in transmittance wavelength dependency with respect to the above-described problem 2.
The fourth object of the present invention is to provide a new phase shift film that is excellent in transmittance wavelength dependency and excellent in surface reflectivity characteristics with respect to the above-described problem 3.
The fifth object of the present invention is to provide a new phase shift film that is excellent in the transmittance wavelength dependency and also excellent in the back surface reflectance characteristics with respect to the problem 4 described above.
The present invention includes a phase shift mask blank for manufacturing a display device including the phase shift film according to the present invention, a method of manufacturing a phase shift mask using the phase shift mask blank, and a display using the phase shift mask. An object is to provide a method for manufacturing a device.

The present inventor has conducted intensive research and development to provide a new phase shift film excellent in transmittance wavelength dependency.
In the phase shift film, “transmittance wavelength dependency in a wavelength range of 365 nm to 436 nm” (appropriately referred to as “predetermined transmittance wavelength dependency”) is compared to ZrSi-based materials (for example, ZrSiON, ZrSiN, ZrSiO). MoSi-based materials (for example, MoSiN, MoSiON, MoSiOCN) were considered to have better transmittance wavelength dependency.
Furthermore, the present inventor, in the course of study, the ZrSi-based material (for example, ZrSiON, ZrSiN, ZrSiO) has a high transmittance (for example, 16% at a wavelength of 365 nm, 20% by adjusting the composition (for example, high oxidation)). , 30% and 40% transmittance), the predetermined wavelength dependency of the transmittance tends to increase (for example, the predetermined transmittance wavelength dependency is 11.0%, 18.1%, 20.5% and 25.4%). Because of this tendency, it has been found that it is very difficult to reduce the predetermined transmittance wavelength dependency.

  Under the circumstances as described above, the present inventor, in the phase shift film composed of two or more laminated films, the phase shift layer (for example, ZrSiON or ZrSiO) and the predetermined metal layer (for example, Cr or Cr) Surprisingly, by satisfying the required optical characteristics of the phase difference and the transmittance by combining with a CrC, CrCN, CrCO, etc. with a content rate of 55 atomic% or more, a predetermined transmittance wavelength dependency is obtained. It has been found that it can be made very small (for example, within 5.5%) (Problem 1 can be realized).

  Furthermore, the present inventor has a predetermined transmittance wavelength dependency of 1. by combining the phase shift layer (ZrSiON) and the metal layer (Cr, CrC (Cr content is 55 atomic% or more and less than 100 atomic%)). It has been found that a phase shift film (Problem 2) having an excellent transmittance wavelength dependency of 0% or less can be realized.

  As a result of further study, the present inventor, in a phase shift film composed of two or more laminated films, a predetermined phase shift layer (phase adjustment layer) (for example, ZrSiO, ZrSiON, MoSiO, MoSiON, etc.) And a metal layer (transmittance wavelength dependency reducing layer) (for example, Cr, CrC having a Cr content of 55 atomic% or more and less than 100 atomic%, CrCN, CrCO, etc.) in combination (in no particular order) It has been found that the wavelength dependency of the transmittance can be made very small (for example, within 5.5%) (function 1) and the back surface reflectance can be controlled (function 4).

  Further, the inventor of the present invention, in a phase shift film composed of three laminated films, sequentially from a substrate side, a predetermined phase shift layer (phase adjustment layer) (for example, ZrSiO, ZrSiON, MoSiO, MoSiON, etc.) Metal layer (transmittance wavelength dependency reducing layer) (for example, Cr, Zr, Mo metal, and CrC, CrCN, CrCO, ZrC, ZrCN, ZrCO with a content of these metals of 55 atomic% or more and less than 100 atomic% , MoC, MoCN, MoCO, and the like) and a predetermined reflectance reduction layer (for example, CrO, CrOCN, CrON, ZrSiON, MoSiON, etc.) can reduce the predetermined transmittance wavelength dependency (Function 1). (For example, within 5.5%), surface reflectance can be reduced (function 2), and surface reflectance is reduced. Kill (e.g. 10% or less) it (function 3), can be controlled backside reflectance (function 4), and found that it is possible to combine all.

  In the phase shift film composed of two or more layers or three layers, the phase shift film with the uppermost layer being Cr-based has good adhesion to the resist film formed thereon.

The present invention has the following configuration.
(Configuration 1)
In the phase shift mask blank for display device manufacture,
A transparent substrate, and a phase shift film formed on the transparent substrate,
The phase shift film is composed of two or more laminated films,
The phase shift film mainly includes a phase shift layer having a function of adjusting a transmittance and a phase difference with respect to exposure light, and a metal layer having a function of adjusting a transmittance wavelength dependency in a wavelength range of 365 nm to 436 nm. Have
The phase shift film has predetermined optical characteristics in which the transmittance and phase difference of the phase shift film with respect to exposure light have predetermined optical characteristics,
The phase shift layer is made of a material containing at least one of metal, silicon, nitrogen and oxygen,
The metal layer is composed of a metal material or a metal and at least one of carbon, fluorine, nitrogen, and oxygen, and the metal content is 55 atomic% or more and less than 100 atomic%. Made of compound materials,
The phase shift film has a transmittance wavelength dependency within a wavelength range of 365 nm or more and 436 nm or less within 5.5%.
(Configuration 2)
In the phase shift mask blank for display device manufacture,
A transparent substrate, and a phase shift film formed on the transparent substrate,
The phase shift film is arranged mainly on the phase shift layer having a function of adjusting the transmittance and phase difference with respect to the exposure light, and the light incident on the surface side of the phase shift film. A reflectance reduction layer having a function of reducing the reflectance with respect to the liquid crystal, and a function of adjusting the transmittance wavelength dependency in a range of wavelengths from 365 nm to 436 nm, which is disposed between the phase shift layer and the reflectance reduction layer. Having a metal layer,
Due to the laminated structure of the phase shift layer, the metal layer, and the reflectance reduction layer, the transmittance and phase difference of the phase shift film with respect to exposure light have predetermined optical characteristics,
The phase shift layer is made of a material containing at least one of metal, silicon, nitrogen and oxygen,
The metal layer is composed of a metal material or a metal and at least one of carbon, fluorine, nitrogen, and oxygen, and the metal content is 55 atomic% or more and less than 100 atomic%. Made of compound materials,
The phase shift mask blank according to claim 1, wherein the phase shift film has a transmittance wavelength dependency within 5.5% in a wavelength range of 365 nm to 436 nm.
(Configuration 3)
In the phase shift film, the surface reflectance of the phase shift film with respect to light incident from the surface side of the phase shift film is 10% or less in a wavelength region of 365 nm to 436 nm. The phase shift mask blank described in 1.
(Configuration 4)
In the phase shift film, the surface reflectance of the phase shift film with respect to light incident from the surface side of the phase shift film is 15% or less in a wavelength region of 350 nm to 436 nm. The phase shift mask blank described in 1.
(Configuration 5)
5. The phase according to claim 1, wherein a back surface reflectance of the phase shift film with respect to light incident from a back surface side of the transparent substrate is 20% or more in a wavelength region of 365 nm to 436 nm. Shift mask blank.
(Configuration 6)
The reflectance reduction layer is made of a metal and a material containing at least one of nitrogen, oxygen and carbon, or a material containing a metal and silicon and at least one of nitrogen, oxygen and carbon. The phase shift mask blank according to any one of configurations 2 to 5.
(Configuration 7)
The metal constituting the metal layer is any one of Cr, Zr, Mo, Ti, Ta and W. The phase shift mask blank according to any one of configurations 1 to 6,
(Configuration 8)
The phase shift mask blank according to any one of configurations 1 to 7, wherein the metal constituting the phase shift layer is any one of Zr, Mo, Ti, Ta, and W.
(Configuration 9)
The phase shift mask blank according to any one of configurations 2 to 8, wherein the metal constituting the reflectance reduction layer is any one of Cr, Zr, Mo, Ti, Ta, and W. .
(Configuration 10)
The phase shift mask blank according to any one of configurations 1 to 9, further comprising a light shielding film formed on the phase shift film.
(Configuration 11)
The phase shift according to Configuration 10, wherein the light shielding film has a film surface reflectance of 15% or less in a wavelength range of 350 nm to 436 nm with respect to light incident from the surface side of the light shielding film. Mask blank.

(Configuration 12)
In a method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the phase shift film of the phase shift mask blank according to any one of configurations 1 to 9, and a drawing process using a laser beam having any wavelength selected from a wavelength range of 350 nm to 436 nm And a step of forming a resist film pattern by development processing,
And a step of etching the phase shift film with the resist film pattern as a mask to form a phase shift film pattern.
(Configuration 13)
In a method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the light-shielding film of the phase shift mask blank described in Configuration 10 or 11, and a drawing process using a laser beam having any wavelength selected from a wavelength range of 350 nm to 436 nm, and a development process The step of forming a resist film pattern,
Etching the light shielding film using the resist film pattern as a mask to form a light shielding film pattern;
Forming a phase shift film pattern by etching the phase shift film using the light shielding film pattern as a mask.
(Configuration 14)
In the manufacturing method of the display device,
A phase shift mask arrangement in which a phase shift mask obtained by the method for producing a phase shift mask according to Configuration 12 or 13 is arranged opposite to the resist film on a substrate with a resist film on which a resist film is formed. Process,
and a pattern transfer step of transferring the phase shift film pattern by irradiating the phase shift mask with composite exposure light including i-line, h-line, and g-line.

According to the present invention, a new phase shift film having excellent transmittance wavelength dependency can be provided.
According to the present invention, it is possible to provide a new phase shift film that is excellent in transmittance wavelength dependency and excellent in other characteristics.
ADVANTAGE OF THE INVENTION According to this invention, the new phase shift film which is exceptionally excellent in the transmittance wavelength dependence can be provided.
According to the present invention, it is possible to provide a new phase shift film that is excellent in transmittance wavelength dependency and excellent in surface reflectance characteristics.
ADVANTAGE OF THE INVENTION According to this invention, the new phase shift film which is excellent also in the back surface reflectance characteristic while being excellent in the transmittance | permeability wavelength dependency can be provided.
According to the present invention, a phase shift mask blank for manufacturing a display device including the phase shift film according to the present invention, a method of manufacturing a phase shift mask using the phase shift mask blank, and the phase shift mask are used. The method for manufacturing the display device can be provided.

It is a schematic diagram which shows the film | membrane structure of the phase shift mask blank which concerns on this invention. It is a schematic diagram which shows the other film | membrane structure of the phase shift mask blank which concerns on this invention. It is a schematic diagram which shows the other film | membrane structure of the phase shift mask blank which concerns on this invention. It is the transmittance | permeability spectrum of the phase shift film of the phase shift mask blank of Example 1 of this invention. It is the transmittance | permeability spectrum of the phase shift film | membrane of the phase shift mask blank of Example 2 of this invention. It is the transmittance | permeability spectrum of the phase shift film of the phase shift mask blank of Example 3 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the following embodiment is one form at the time of actualizing this invention, Comprising: This invention is not limited within the range. 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)
In the first embodiment, a phase shift mask blank will be described.

FIG. 1 is a schematic diagram showing the film configuration of the phase shift mask blank 10.
The phase shift mask blank 10 includes a transparent substrate 20 transparent to exposure light (having translucency), and a phase shift film 30 disposed on the transparent substrate 20. In FIG. 1, the phase shift film 30 has a laminated structure including a phase shift layer 31, a metal layer 33, and a reflectance reduction layer 32 arranged in order from the transparent substrate 20 side. A laminated structure having the phase shift layer 31 and the metal layer 33 arranged in order from the transparent substrate 20 side may be used.

The phase shift layer 31 is disposed on the main surface of the transparent substrate 20. The phase shift layer 31 has a function of adjusting the transmittance and the phase difference with respect to the exposure light.
The phase shift layer 31 is formed of a material containing metal (M), silicon (Si), and at least one of nitrogen (N) and oxygen (O). The phase shift layer 31 includes metal (M), silicon (Si), and at least one of nitrogen (N) and oxygen (O), and further includes carbon (C) and fluorine (F). It may be formed of a material containing at least one of the above. For example, as a material for forming the phase shift layer 31, metal silicide oxynitride (MSSiON), metal silicide nitride (MSiN), metal silicide oxide (MSiO), metal silicide oxycarbonitride (MSiCN), metal silicide carbonization Nitride (MSiCN), metal silicide oxycarbide (MSioC), metal silicide oxynitride fluoride (MSiONF), metal silicide oxynitride (MSiNF), metal silicide oxyfluoride (MSSiOF), metal silicide oxycarbonitride ( MSiOCNF), metal silicide carbonitride / fluoride (MSiCNF), metal silicide oxycarbonitride (MSiOCF), and the like.
The metal (M) constituting the phase shift layer 31 is typically zirconium (Zr), and then molybdenum (Mo). Examples of other metals (M) constituting the phase shift layer 31 include transition metals such as titanium (Ti), tantalum (Ta), and tungsten (W).
For example, examples of the material for forming the phase shift layer 31 include ZrSiON, ZrSiN, ZrSiO, ZrSiOCN, ZrSiCN, ZrSiCO, ZrSiONF, ZrSiNF, ZrSiOF, ZrSiOCNF, ZrSiCNF, and ZrSiCOF.
For example, the material for forming the phase shift layer 31 includes MoSiON, MoSiN, MoSiO, MoSiOCN, MoSiCN, MoSiCO, MoSiONF, MoSiNF, MoSiOF, MoSiOCNF, MoSiCNF, and MoSiCOF.
For example, examples of the material for forming the phase shift layer 31 include TiSiON, TiSiN, TiSiO, TiSiOCN, TiSiCN, TiSiCO, TiSiONF, TiSiNF, TiSiOF, TiSiOCNF, TiSiCNF, and TiSiCOF.
The phase shift layer 31 may contain elements other than those listed above without departing from the effects of the present invention. The ratio (atomic ratio) of metal (M) to silicon (Si) of the metal silicide (MSi) of the phase shift layer 31 is M: Si = 1 in order to obtain the optical characteristics of the phase shift film 30 of the present invention. : 1 or more and 1: 9 or less are preferable. When patterning the phase shift film 30 by wet etching, the ratio (atomic ratio) between the metal (M) and silicon (Si) of the phase shift layer 31 is M: Si = 1: 1 to 1: 8, more preferably M: Si = 1: 1 to 1: 4.
Further, the metal (M) constituting the phase shift layer 31 may be an alloy containing one or more of the metals listed above.
The phase shift layer 31 can be formed by a sputtering method.

The reflectance reduction layer 32 is disposed on the upper side of the phase shift layer 31. The reflectance reduction layer 32 has a function of reducing the reflectance with respect to light incident from the surface side of the phase shift film 30 (that is, the side opposite to the transparent substrate 20 side with respect to the reflectance reduction layer 32).
The reflectance reduction layer 32 can be formed of a metal and a material containing at least one of nitrogen, oxygen and carbon, or a material containing a metal and silicon and at least one of nitrogen, oxygen and carbon.
For example, as a material for forming the reflectance reduction layer 32, metal oxide (MO), metal oxynitride (MON), metal oxycarbonitride (MOCN), metal oxycarbide (MOC), metal oxyfluoride (MOF) ), Metal oxynitride fluoride (MONF), metal oxycarbonitride fluoride (MOCNF), metal oxycarbide fluoride (MOCF), metal nitride (MN), metal carbide (MC), metal carbonitride (MCN) , Metal fluoride (MF), metal nitride fluoride (MNF), metal carbonitride fluoride (MCNF), metal carbide fluoride (MCF), and the like.
The metal (M) constituting the reflectance reduction layer 32 is typically chromium (Cr), zirconium (Zr), or molybdenum (Mo). Examples of the other metal (M) constituting the reflectance reduction layer 32 include transition metals such as titanium (Ti), tantalum (Ta), and tungsten (W).
For example, the reflectance reduction layer 32 is made of chromium oxide (CrO), chromium oxynitride (CrON), chromium oxycarbonitride (CrOCN), chromium oxycarbide (CrCO), chromium oxyfluoride (CrOF), chromium oxide. Nitride fluoride (CrONF), chromium oxide carbonitride fluoride (CrOCNF), chromium oxide carbonitride (CrOCF), chromium nitride (CrN), chromium carbide (CrC), chromium carbonitride (CrCN), chromium fluoride ( CrF), chromium nitride fluoride (CrNF), chromium carbonitride fluoride (CrCNF), chromium carbide fluoride (CrCF) and the like.
Further, for example, the material for forming the reflectance reduction layer 32 can be formed of metal, silicon, and a metal silicide-based material containing at least one of nitrogen, oxygen, and carbon. ZrSiON, ZrSiN, ZrSiO, ZrSiOCN, ZrSiCN ZrSiCO, ZrSiONF, ZrSiNF, ZrSiOF, ZrSiOCNF, ZrSiCNF, ZrSiCOF can be used.
In addition, for example, the material for forming the reflectance reduction layer 32 includes MoSiON, MoSiN, MoSiO, MoSiOCN, MoSiCN, MoSiCO, MoSiONF, MoSiNF, MoSiOF, MoSiOCNF, MoSiCNF, and MoSiCOF.
For example, the material for forming the reflectance reduction layer 32 includes TiSiON, TiSiN, TiSiO, TiSiOCN, TiSiCN, TiSiCO, TiSiONF, TiSiNF, TiSiOF, TiSiOCNF, TiSiCNF, and TiSiCOF.
The reflectance reduction layer 32 may contain elements other than those listed above without departing from the effects of the present invention.
When the material of the reflectance reduction layer 32 is a metal silicide (MSi) -based material, the ratio (atomic ratio) of metal (M) to silicon (Si) obtains the optical characteristics of the phase shift film 30 of the present invention. Therefore, M: Si = 1: 1 or more and 1: 9 or less is preferable. When patterning the phase shift film 30 by wet etching, the ratio (atomic ratio) of the metal (M) and silicon (Si) of the reflectance reduction layer 32 is M: Si from the viewpoint of improving the pattern cross section. = 1: 2 to 1: 8, more preferably M: Si = 1: 2 to 1: 4.
Further, the metal (M) constituting the phase shift layer 31 may be an alloy containing one or more of the metals listed above.
The reflectance reduction layer 32 can be formed by a sputtering method.

The metal layer 33 is disposed between the phase shift layer 31 and the reflectance reduction layer 32. The metal layer 33 has a function and function capable of adjusting mainly the transmittance wavelength dependency of the phase shift layer 31 as a single layer. Specifically, the metal layer 33 has an action and function that can reduce the transmittance wavelength dependency of the phase shift layer 31 as a single layer mainly by a predetermined value (predetermined width) or more. The metal layer 33 has a function and function of controlling the transmittance wavelength dependency of the phase shift film 30 in the entire laminated body to be a predetermined value or less. In addition to these functions and functions, the metal layer 33 has a function of adjusting the transmittance with respect to the exposure light, and in combination with the reflectance reduction layer 32, the surface side of the phase shift film 30 (transparent substrate 20 side is It has a function of reducing the reflectance with respect to light incident from the opposite side. In combination with the phase shift layer 31, the metal layer 33 has a function of improving the back surface reflectance with respect to light incident on the phase shift film 30 from the back surface side of the transparent substrate 20. The back surface of the transparent substrate 20 means a main surface opposite to the phase shift film 30 out of the two main surfaces of the transparent substrate 20.
The metal layer 33 is made of a material made of metal (M), or made of metal (M) and at least one of carbon (C), fluorine (F), nitrogen, and oxygen. ) Is a metal compound material having a content of 55 atomic% or more.
For example, as a material for forming the metal layer 33, metal (M), metal carbide (MC), metal fluoride (MF), metal nitride (MN), metal oxide (MO), metal carbide fluoride (MCF) , Metal oxycarbide (MOC), metal oxynitride (MON), metal oxyfluoride (MOF), metal carbonitride (MCN), metal oxynitride (MNF), metal oxycarbonitride (MOCN), metal Examples thereof include oxynitride fluoride (MONF), metal oxycarbide fluoride (MOCF), metal carbonitride fluoride (MCNF), and metal oxycarbonitride fluoride (MOCNF).
The metal element (M) content in the metal layer 33 is preferably 60 to 100 atomic%, and more preferably 65 to 95 atomic%.
The metal (M) constituting the metal layer 33 is typically chromium (Cr). Examples of other metals (M) constituting the metal layer 33 include transition metals such as zirconium (Zr), molybdenum (Mo), titanium (Ti), tantalum (Ta), and tungsten (W).
For example, as a material for forming the metal layer 33, chromium (Cr), chromium carbide (CrC), chromium fluoride (CrF), chromium nitride (CrN), chromium oxide (CrO), chromium carbide fluoride (CrCF) , Chromium oxide carbide (CrOC), chromium oxynitride (CrON), chromium oxyfluoride (CrOF), chromium carbonitride (CrCN), chromium nitride fluoride (CrNF), chromium oxycarbonitride (CrOCN), chromium Examples thereof include oxynitride fluoride (CrONF), chromium oxycarbide fluoride (CrOCF), chromium oxycarbonitride fluoride (CrCNF), and chromium oxynitride fluoride (CrOCNF).
By providing the metal layer 33, the sheet resistance of the phase shift film is lowered, so that charge up of the phase shift mask blank and the phase shift mask can be prevented. In the case where the metal layer 33 is not provided, adhesion of foreign matter or electrostatic breakdown is likely to occur due to charge-up.
The metal layer 33 may contain elements other than those listed above without departing from the effects of the present invention.
Further, the metal (M) constituting the metal layer 33 may be an alloy containing one or more of the metals listed above.
The metal layer 33 can be formed by a sputtering method.

The metal layer 33 has a metal element (M) content (atomic%) higher than the metal element (M) content (atomic%) of the reflectance reduction layer 32.
The difference between the metal element (M) content of the metal layer 33 and the metal element (M) content of the reflectance reduction layer 32 is preferably 30 to 90 atomic%, more preferably 50 to 80 atomic%. It is. When the difference in the metal element (M) content is 60 to 80 atomic%, the above wavelength range (365 nm wavelength or 365 nm to 436 nm wavelength range) at the interface between the metal layer 33 and the reflectance reduction layer 32. Since the reflectance in can be increased, the effect of reducing the reflectance is further exhibited, which is preferable.
The etching rate of the metal layer 33 can be adjusted by adding carbon (C), fluorine (F), nitrogen (N), and oxygen (O) to the metal (M). For example, when the metal (M) is chromium (Cr), the wet etching rate can be reduced by adding carbon (C) or fluorine (F) to the chromium (Cr). By adding nitrogen (N) or oxygen (O) to chromium (Cr), the wet etching rate can be increased. The etching rate of the phase shift layer 31 and the reflectance reduction layer 32 formed above and below the metal layer 33 is carbon (C) in the case of a metal silicide material of metal (M) and silicon (Si). By adding oxygen, fluorine (F), and nitrogen (N), the wet etching rate can be slowed, and by including oxygen (O) in the metal silicide material of metal (M) and silicon (Si). The wet etching rate can be increased. Further, when the material of the reflectance reduction layer 32 is a metal and a material containing at least one of nitrogen, oxygen, and carbon, when the metal is chromium (Cr), carbon (C) or fluorine (F ) Can be included to reduce the wet etching rate. By adding nitrogen (N) or oxygen (O) to chromium (Cr), the wet etching rate can be increased. By these, the etching rate of each layer which comprises the phase shift film 30 can be controlled, and the cross-sectional shape of the phase shift film 30 after an etching can be made favorable.
The metal layer 33 has a metal element (M) content higher than the metal element (M) content of the phase shift layer 31.
The difference between the metal element (M) content of the metal layer 33 and the metal element (M) content of the phase shift layer 31 is preferably 30 to 90 atomic%, more preferably 50 to 80 atomic%. is there. When the difference in the metal element (M) content between the metal layer 33 and the phase shift layer 31 is 60 to 80 atomic%, the above-mentioned wavelength range (365 nm wavelength, or the interface between the metal layer 33 and the phase shift layer 31) Since the back surface reflectance in the wavelength range of 365 nm to 436 nm can be increased, the back surface reflectance can be further increased, which is preferable.
The metal element (M) content can be measured using an X-ray photoelectron spectrometer (XPS, ESCA) or the like.

The thickness of the phase shift layer 31 in the phase shift film 3 is preferably, for example, in the range of 50 nm to 140 nm, and more preferably in the range of 60 nm to 120 nm, but is not limited thereto. From the viewpoint of increasing the back surface reflectance, the thickness of the phase shift layer 31 is preferably 70 nm to 95 nm, and more preferably 70 nm to 85 nm.
The thickness of the metal layer 33 in the phase shift film 3 is preferably thinner than the thickness of the phase shift layer. The thickness of the metal layer 33 in the phase shift film 3 is preferably thinner than the thickness of the reflectance reduction layer. The thickness of the metal layer 33 in the phase shift film 3 varies depending on the type of metal (M), and thus cannot be generally stated. For example, the thickness is in a range of 2.5 nm to 50 nm, and further, 2.5 nm to 40 nm. However, it is not limited to this. It is substantially difficult to form a metal (M) layer uniformly with a thickness of less than 2.5 nm over the substrate surface. Further, when the metal (M) layer is formed with a thickness exceeding 50 nm, the transmittance decreases, and for example, the transmittance of the phase shift film 3 at a wavelength of 365 nm may be less than 1%. From the viewpoint of increasing the surface reflectance, the metal layer 33 is preferably thicker. From the viewpoint of increasing the back surface reflectance, the thickness of the metal layer 33 is 25 nm or more. From the above viewpoint, the thickness of the metal layer 33 is preferably 25 nm or more and 50 nm or less, and more preferably 25 nm or more and 40 nm or less.
The thickness of the reflectance reduction layer 32 in the phase shift film 3 is preferably in the range of, for example, 15 nm to 40 nm, and more preferably 20 nm to 35 nm, but is not limited thereto.

Each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 preferably has a refractive index of 2.0 or more in a wavelength range of 365 nm to 436 nm. When the refractive index is 2.0 or more, the thickness of the phase shift film 30 necessary for obtaining desired optical characteristics (transmittance and phase difference) can be reduced. Therefore, the phase shift mask manufactured using the phase shift mask blank 10 provided with the phase shift film 30 can include a phase shift film pattern having excellent pattern cross-sectional shape and excellent CD uniformity.
The refractive index can be measured using an n & k analyzer or an ellipsometer.

Due to the laminated structure of the phase shift layer 31 and the metal layer 33, or the laminated structure of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32, the transmittance and phase difference of the phase shift film 30 with respect to the exposure light are set to a predetermined optical value. In addition to having characteristics, the transmittance wavelength dependency (transmission variation range) has a predetermined value.
The transmittance of the phase shift film 30 with respect to the exposure light satisfies a value necessary for the phase shift film 30. The transmittance of the phase shift film 30 is preferably 1% or more and 50% or less with respect to light having a predetermined wavelength included in exposure light (hereinafter referred to as a representative wavelength). That is, when the exposure light is a composite light including j-line (wavelength: 313 nm), i-line (wavelength: 365 nm), h-line (wavelength: 405 nm), and g-line (wavelength: 436 nm), the phase shift film 30 is It has the above-described transmittance with respect to light of a representative wavelength included in the wavelength range. For example, when the exposure light is composite light including i-line, h-line, and g-line, the phase shift film 30 has the above-described transmittance with respect to any of i-line, h-line, and g-line. .
The phase difference of the phase shift film 30 with respect to the exposure light satisfies a value necessary for the phase shift film 30. The phase difference of the phase shift film 30 is preferably 160 ° to 200 °, and more preferably 170 ° to 190 ° with respect to the light having the representative wavelength included in the exposure light. Thereby, the phase of the light of the representative wavelength contained in the exposure light can be changed from 160 ° to 200 °. For this reason, a phase difference of 160 to 200 ° is generated between the light with the representative wavelength transmitted through the phase shift film 30 and the light with the representative wavelength transmitted through only the transparent substrate 20. That is, when the exposure light is a composite light including light having a wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-described phase difference with respect to light having a representative wavelength included in the wavelength range. For example, when the exposure light is composite light including i-line, h-line, and g-line, the phase shift film 30 has the above-described phase difference with respect to any of i-line, h-line, and g-line.
The phase shift film 30 has a transmittance wavelength dependency within 5.5% within a wavelength range of 365 nm to 436 nm.
The transmittance, wavelength dependency, and phase difference of the phase shift film 30 are determined by the phase shift layer 31 and the metal layer 33 constituting the phase shift film 30, or the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32. It is possible to control by adjusting the material, composition and thickness of each. Therefore, in this embodiment, the phase shift layer 31 and the metal layer 33, or the phase shift so that the transmittance, transmittance wavelength dependency, and phase difference of the phase shift film 30 have the predetermined optical characteristics described above. The material, composition, and thickness of each of the layer 31, the metal layer 33, and the reflectance reduction layer 32 are adjusted. Note that the transmittance and transmittance wavelength dependency of the phase shift film 30 are mainly affected by the material, composition, and thickness of the phase shift layer 31 and the metal layer 33. The refractive index and the phase difference (phase shift amount) of the phase shift film 30 are mainly affected by the material, composition, and thickness of the phase shift layer 31.
The transmittance and the phase difference can be measured using a phase shift amount measuring device or the like.

The surface reflectance of the phase shift film 30 with respect to the light incident from the surface side of the phase shift film 30 is 10% or less in the wavelength region of 365 nm to 436 nm, and / or the light incident from the surface side of the phase shift film 30. The surface reflectance of the phase shift film 30 is 15% or less in the wavelength region of 350 nm to 436 nm. When the surface reflectance of the phase shift film 30 is 10% or less in the wavelength region of 365 nm to 436 nm and / or the surface reflectance of the phase shift film 30 is 15% or less in the wavelength region of 350 nm to 436 nm. When a resist film is formed thereon and pattern drawing is performed by a laser drawing machine or the like, it is less likely to be affected by standing waves caused by overlapping of light used for drawing and its reflected light. For this reason, the roughness of the edge portion of the cross section of the resist film pattern on the phase shift film 30 can be suppressed during pattern drawing, and the pattern accuracy can be improved. For this reason, a phase shift mask having excellent pattern accuracy can be formed. Further, since the surface reflectance with respect to the exposure light is reduced, when the display device is manufactured by performing pattern transfer using a phase shift mask, the transfer pattern is blurred (flared) due to the reflected light from the display device substrate. And CD errors can be prevented.
The fluctuation range of the surface reflectance of the phase shift film 30 is preferably 10% or less, more preferably 8% or less, further preferably 5% or less, and more preferably 3% or less in the wavelength region of 365 nm to 436 nm. is there. Further, the fluctuation range of the surface reflectance of the phase shift film 30 is preferably 12% or less, more preferably 10% or less, further preferably 8% or less, more preferably 5 in the wavelength region of 350 nm to 436 nm. % Or less.
The back surface reflectance of the phase shift film 30 with respect to light incident from the back surface side of the transparent substrate 20 is one of i line (365 nm), h line (405 nm), and g line (436 nm), preferably two. In the above wavelengths, it is more preferably 15% or more, more preferably 18% or more, more preferably 20% or more, and further preferably 30% or more in the wavelength range of 365 nm to 436 nm. Thereby, the phase shift film 30 can absorb the exposure light and reduce the pattern position shift caused by thermal expansion. Further, the fluctuation range of the back surface reflectance of the phase shift film 30 is 20% or less, more preferably 15% or less, more preferably 10% or less, and further preferably 5% or less in the wavelength region of 365 nm to 436 nm. Is preferred.
The surface reflectance of the phase shift film 30 and the fluctuation range thereof adjust the refractive index, extinction coefficient, and thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 constituting the phase shift film 30. Can be controlled. Since the extinction coefficient and the refractive index can be controlled by adjusting the composition, in this embodiment, the surface reflectance of the phase shift film 30 and the fluctuation range thereof have the predetermined physical properties described above. The materials, compositions, and thicknesses of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 are adjusted. The same applies to the back surface reflectance of the phase shift film 30. The surface reflectance of the phase shift film 30 and its fluctuation range are mainly affected by the material, composition, and thickness of the metal layer 33 and the reflectance reduction layer 32. Further, the back surface reflectance of the phase shift film 30 and its fluctuation range are mainly affected by the material, composition, and thickness of the metal layer 33 and the phase shift layer 31.
The surface reflectance and the back surface reflectance can be measured using a spectrophotometer or the like. The fluctuation range of the surface reflectance is obtained from the difference between the maximum reflectance and the minimum reflectance in the wavelength range of 350 nm to 436 nm or in the wavelength range of 365 nm to 436 nm. Further, the fluctuation range of the back surface reflectance is obtained from the difference between the maximum reflectance and the minimum reflectance in the wavelength range of 365 nm to 436 nm.

  The phase shift layer 31 may be composed of a single film having a uniform composition, or may be composed of a plurality of films having different compositions, or the composition continuously changes in the thickness direction. It may be composed of a single film, or may be composed of a plurality of films having different compositions, and each of the plurality of films may be composed of films whose compositions continuously change in the thickness direction. . The same applies to the metal layer 33 and the reflectance reduction layer 32.

  FIG. 2 is a schematic diagram showing another film configuration of the phase shift mask blank 10. As shown in FIG. 2, the phase shift mask blank 10 may include a light shielding film pattern 40 between the transparent substrate 20 and the phase shift film 30.

When the phase shift mask blank 10 includes the light shielding film pattern 40, the light shielding film pattern 40 is disposed on the main surface of the transparent substrate 20. The light blocking film pattern 40 has a function of blocking the transmission of exposure light.
The material for forming the light-shielding film pattern 40 is not particularly limited as long as the material has a function of blocking the transmission of exposure light. For example, a chromium-based material, a material including the above-described metal (M) (M: any one of Zr, Mo, Ti, Ta, and W), and the above-described metal (M) and silicon (Si) are included. Materials and the like. Examples of the chromium-based material include chromium (Cr) or a chromium compound containing chromium (Cr) and at least one of carbon (C) and nitrogen (N). In addition, a chromium compound containing chromium (Cr) and at least one of oxygen (O) and fluorine (F), or at least one of chromium (Cr), carbon (C), and nitrogen (N) And a chromium compound containing at least one of oxygen (O) and fluorine (F). For example, as a material for forming the light-shielding film pattern 40, Cr, CrC, CrN, CrO, CrCN, CrON, CrCO, and CrCON are listed.
The light shielding film pattern 40 can be formed by patterning a light shielding film formed by a sputtering method by etching.

In the portion where the phase shift film 30 and the light shielding film pattern 40 are laminated, the optical density with respect to the exposure light is preferably 3 or more, more preferably 4 or more, and further preferably 5 or more.
The optical density can be measured using a spectrophotometer or an OD meter.

  The light-shielding film pattern 40 may be composed of a single film having a uniform composition, or may be composed of a plurality of films having different compositions, and the composition is continuously in the thickness direction. It may be composed of a single film that changes, or it may be composed of a plurality of films having different compositions, and each of the plurality of films may be composed of films whose compositions continuously change in the thickness direction. Good.

  1 and 2, the phase shift mask blank 10 may include a resist film on the phase shift film 30.

FIG. 3 is a schematic diagram showing another film configuration of the phase shift mask blank 10.
The phase shift mask blank 10 of the present invention includes a transparent substrate 20 and a phase shift film 30 formed on the transparent substrate 20, and a light shielding film 45 formed on the phase shift film 30. Good. Further, a configuration in which a resist film (not shown) is formed on the light shielding film 45 may be employed.
In this case, as the light shielding film 45, the same contents as those described in the light shielding film pattern 40 can be applied. For example, as the material of the light shielding film 45, the same material as the material for forming the light shielding film pattern 40 can be used. If necessary, the light shielding film 45 having an antireflection function may be formed by forming the surface reflectance reduction layer 47 for reducing the film surface reflectance of the light shielding film 45 with respect to light incident on the surface side of the light shielding film 45. Absent. In this case, the light shielding film 45 includes a light shielding layer 46 having a function of shielding the transmission of exposure light from the phase shift film 30 side, and a surface reflectance reduction layer 47. When the light shielding film 45 includes the surface reflectance reduction layer 47, the film surface reflectance of the light shielding film 45 with respect to light incident from the surface side of the surface reflectance reduction layer 47 is 10% in a wavelength region of 365 nm to 436 nm. It is preferable that the film surface reflectance of the light shielding film 45 with respect to light incident from the surface side of the surface reflectance reduction layer 47 is 15% or less in the wavelength range of 350 nm to 436 nm. Further, if necessary, between the phase shift film 30 and the light shielding film pattern 40 shown in FIG. 2, between the phase shift film 30 and the light shielding film 45 shown in FIG. Other functional films can also be formed. Examples of the functional film include an etching stopper film and an etching mask film.

Next, a method for manufacturing the phase shift mask blank 10 of this embodiment will be described. The phase shift mask blank 10 is manufactured by performing the following preparation process and phase shift film formation process.
Hereinafter, each process will be described in detail.

(Preparation process)
In the preparation step, first, the transparent substrate 20 is prepared. The material of the transparent substrate 20 is not particularly limited as long as it is a material having translucency with respect to the exposure light to be used. Examples thereof include synthetic quartz glass, soda lime glass, and alkali-free glass. For example, when there is no surface reflection loss, the transparent substrate 20 has a transmittance of 85% or more, preferably 90% or more, with respect to exposure light.
In the case of manufacturing the phase shift mask blank 10 including the light-shielding film pattern 40, a light-shielding film made of, for example, a chromium-based material is formed on the transparent substrate 20 by sputtering. Thereafter, a resist film pattern is formed on the light shielding film, and the light shielding film is etched using the resist film pattern as a mask to form the light shielding film pattern 40. Thereafter, the resist film pattern is peeled off. These steps are omitted when the phase shift mask blank 10 without the light-shielding film pattern 40 is manufactured.

(Phase shift film forming process)
In the phase shift film forming step, the phase shift film 30 is formed on the transparent substrate 20 by sputtering. Here, when the light-shielding film pattern 40 is formed on the transparent substrate 20, the phase shift film 30 is formed so as to cover the light-shielding film pattern 40.

  The phase shift film 30 is formed by forming a phase shift layer 31 on the main surface of the transparent substrate 20 and forming a metal layer 33 on the phase shift layer 31. Alternatively, the phase shift film 30 is formed by forming the phase shift layer 31 on the main surface of the transparent substrate 20, forming the metal layer 33 on the phase shift layer 31, and forming the reflectance reduction layer 32 on the metal layer 33. It is formed by forming a film.

The film formation of the phase shift layer 31 and the reflectance reduction layer 32 is performed from, for example, helium gas, neon gas, argon gas, krypton gas, and xenon gas using a sputter target containing metal (M) or a metal (M) compound. An inert gas including at least one selected from the group consisting of: 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 sputtering gas atmosphere made of a mixed gas with an active gas. Examples of the hydrocarbon gas include methane gas, butane gas, propane gas, and styrene gas.
The metal layer 33 is formed using at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas using a sputtering target containing metal (M) or a metal (M) compound. Is carried out in an inert gas atmosphere. When the metal layer 33 contains carbon, the metal layer 33 is formed in a sputtering gas atmosphere made of a mixed gas of the inert gas and the hydrocarbon-based gas. When the metal layer 33 contains nitrogen, oxygen, and fluorine, the metal layer 33 is formed in the same manner as the phase shift layer 31 and the reflectance reduction layer 32.

  When the phase shift layer 31 and the metal layer 33 are formed, or when the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 are formed, the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 are formed. The material, composition, and thickness of each of the phase shift film 30 have the above-described predetermined optical characteristics of the transmittance and phase difference, and the wavelength dependency of the transmittance of the phase shift film 30 (the variation range of the transmittance). ) Has the above-mentioned predetermined characteristics, and further, the front surface reflectance and its fluctuation range, and the back surface reflectance and its fluctuation range of the phase shift film 30 are adjusted to have the above-mentioned predetermined characteristics. The composition of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be controlled by the composition and flow rate of the sputtering gas. The thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be controlled by sputtering power, sputtering time, and the like. Further, when the sputtering apparatus is an in-line type sputtering apparatus, the thickness of each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be controlled also by the transport speed of the substrate.

When the phase shift layer 31 is composed of a single film having a uniform composition, the above-described film forming process is performed only once without changing the composition and flow rate of the sputtering gas. When the phase shift layer 31 includes a plurality of films having different compositions, the above-described film formation process is performed a plurality of times while changing the composition and flow rate of the sputtering gas for each film formation process. When the phase shift layer 31 is made of a single film whose composition changes continuously in the thickness direction, the film forming process described above is performed only once while changing the composition and flow rate of the sputtering gas. When the phase shift layer 31 is composed of a plurality of films having different compositions and each of the plurality of films is composed of a film whose composition changes continuously in the thickness direction, the above-described deposition process is performed using the composition and flow rate of the sputtering gas. Perform multiple times while changing.
The same applies to the formation of the metal layer 33 and the formation of the reflectance reduction layer 32. When the film forming process is performed a plurality of times, the sputtering power applied to the sputtering target can be reduced.

It is preferable that the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 are continuously formed by using a sputtering apparatus without taking the transparent substrate 20 out of the apparatus and exposing it to the atmosphere. By continuously forming the film without taking it out of the apparatus, unintended surface oxidation and surface carbonization of each layer can be prevented. Unintentional surface oxidation or surface carbonization of each layer transfers the phase shift film pattern to the laser beam used when drawing the resist film formed on the phase shift film 30 or the resist film formed on the display device substrate. There is a possibility that the reflectance with respect to the exposure light used at the time may be changed, or the etching rate of the oxidized portion or the carbonized portion may be changed.
The phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 can be continuously formed using an in-line type sputtering apparatus or a cluster type sputtering apparatus without exposing the substrate to the atmosphere.

In addition, as shown in FIG. 3, when manufacturing the phase shift mask blank 10 provided with the phase shift film 30 and the light shielding film 45 on the transparent substrate 20, the phase shift film 30 was formed by the phase shift film formation process demonstrated above. Thereafter, a light shielding film 45 is formed on the phase shift film 30.
(Shading film forming process)
In the light shielding film forming step, the light shielding film 45 is formed on the phase shift film 30 by sputtering.
The light shielding film 45 is formed by forming a light shielding layer 46 on the phase shift film 30 and, if necessary, a surface reflectance reduction layer 47 on the light shielding layer 46. The light shielding layer 46 and the surface reflectance reduction layer 47 are formed by using one or more sputter targets including a metal (M), a metal (M) compound, a metal silicide (MSi), or a metal silicide (MSi) compound. For example, an inert gas containing at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas, and oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, It is performed in a sputtering gas atmosphere made of a mixed gas with an active gas containing at least one selected from the group consisting of carbon gas, hydrocarbon gas, and fluorine gas, or in a sputtering gas atmosphere containing at least one of the inert gases. Examples of the hydrocarbon gas include methane gas, butane gas, propane gas, and styrene gas.
When the light shielding layer 46 and the surface reflectance reducing layer 47 are formed, the material, composition, and thickness of the light shielding layer 46 and the surface reflectance reducing layer 47 are the portions where the phase shift film 30 and the light shielding film 45 are laminated. , The optical density with respect to the exposure light and the film surface reflectance are adjusted so as to have the predetermined optical characteristics described above. The composition of each of the light shielding layer 46 and the surface reflectance reduction layer 47 can be controlled by the composition and flow rate of the sputtering gas. The thicknesses of the light shielding layer 46 and the surface reflectance reduction layer 47 can be described by the sputtering power, the sputtering time, and the like. Further, when the sputtering apparatus is an in-line type sputtering apparatus, the thickness of each of the light shielding layer 46 and the surface reflectance reduction layer 47 can be controlled also by the transport speed of the substrate.
When each of the light shielding layer 46 and the surface reflectance reduction layer 47 is made of a single film having a uniform composition, the above-described film forming process is performed only once without changing the composition and flow rate of the sputtering gas. When each of the light shielding layer 46 and the surface reflectance reduction layer 47 is composed of a plurality of films having different compositions, the above-described film forming process is performed a plurality of times while changing the composition and flow rate of the sputtering gas for each film forming process. When each layer of the light shielding layer 46 and the surface reflectance reduction layer 47 is formed of a single film whose composition continuously changes in the thickness direction, the film formation process described above is performed while changing the composition and flow rate of the sputtering gas. Perform only once. When each of the light shielding layer 46 and the surface reflectance reduction layer 47 is composed of a plurality of films having different compositions and the plurality of films are each composed of a film whose composition continuously changes in the thickness direction, the above-described film formation process Is performed a plurality of times while changing the composition and flow rate of the sputtering gas.
The light shielding layer 46 and the surface reflectance reduction layer 47 can be continuously formed using an in-line type sputtering apparatus or a cluster type sputtering apparatus without exposing the substrate to the atmosphere.
In addition, when manufacturing the phase shift mask blank 10 provided with a resist film, next, a resist film is formed on a light shielding film.

  Since the phase shift mask blank 10 of the first embodiment includes the phase shift layer 31 and the metal layer 33 as the phase shift film 30, after satisfying the predetermined optical characteristics of the phase difference and the transmittance, In the wavelength range of 365 nm to 436 nm, the transmittance wavelength dependency is excellent (within 5.5%). Furthermore, the phase shift mask blank 10 having the phase shift film 30 including the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 satisfies the predetermined optical characteristics of the phase difference and the transmittance, and is 365 nm or more. In the wavelength range of 436 nm or less, the transmittance wavelength dependency is excellent (within 5.5%), the surface reflectance property is also excellent (10% or less), and the back surface reflectance property is also excellent.

(Embodiment 2)
In the second embodiment, a method of manufacturing a phase shift mask using the phase shift mask blank 10 of the first embodiment will be described. Embodiment 2 includes Embodiment 2-1 and Embodiment 2-2. Embodiment 2-1 is a method of manufacturing a phase shift mask using the phase shift mask blank 10 in which the phase shift film 30 and the resist film are formed on the transparent substrate 20. The embodiment 2-2 is a method of manufacturing a phase shift mask using the phase shift mask blank 10 in which the phase shift film 30, the light shielding film 45, and the resist film are formed on the transparent substrate 20. In the manufacturing method of the phase shift mask of the embodiment 2-1, the phase shift mask is manufactured by performing the following resist film pattern forming step and phase shift film pattern forming step. In the method of manufacturing the phase shift mask according to the embodiment 2-2, the phase shift mask is manufactured by performing the following resist film pattern forming step, light shielding film pattern forming step, and phase shift film pattern forming step.
Hereinafter, each process will be described in detail.

(Resist film pattern formation process)
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 first embodiment described in FIG. 1 or FIG. The resist film material to be used is not particularly limited. The resist film material is, for example, one that is sensitive to laser light having any wavelength selected from a wavelength range of 350 nm to 436 nm, which will be described later, or is selected from a wavelength range of 365 nm to 436 nm. Those which are sensitive to laser light having any wavelength are used. Further, the resist film may be either a positive type or a negative type.
Then, using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm or a laser beam having any wavelength selected from the wavelength range of 365 nm to 436 nm, a predetermined film is applied to the resist film. Draw a pattern. Examples of the pattern drawn on the resist film include a line and space pattern and a hole pattern.
Thereafter, the resist film is developed with a predetermined developer to form a resist film pattern on the phase shift film 30.
If the phase shift mask blank 10 is already provided with a resist film on the phase shift film 30, the step of forming the resist film on the phase shift film 30 is omitted.

(Light shielding film pattern forming process)
In the light shielding film pattern forming step in the manufacturing method of the phase shift mask of the embodiment 2-2, the light shielding film 45 (FIG. 3) is etched using the resist film pattern as a mask to form the light shielding film pattern.
The etching medium (etching solution, etching gas) for etching the light shielding film 45 is not particularly limited as long as each of the light shielding layer 46 and the surface reflectance reduction layer 47 constituting the light shielding film 45 can be selectively etched.
Specifically, for example, as an etchant for wet etching a metal silicide-based material, at least one fluorine compound selected from hydrofluoric acid, hydrosilicofluoric acid, and ammonium hydrogen fluoride, hydrogen peroxide, An etching solution containing at least one oxidizing agent selected from nitric acid and sulfuric acid, and an etching solution containing at least one oxidizing agent selected from hydrogen peroxide, ammonium fluoride, phosphoric acid, sulfuric acid, and nitric acid. Can be mentioned. Examples of the etching gas for dry etching the metal silicide material layer include a fluorine-based gas and a chlorine-based gas. Examples of the fluorine-based gas include CF4 gas, CHF3 gas, SF6 gas, and those obtained by mixing O2 gas with these gases.
For example, as an etchant for wet-etching a chromium-based material, an etching solution containing ceric ammonium nitrate and perchloric acid, or an etching gas composed of a mixed gas of chlorine gas and oxygen gas can be given.
(Phase shift film pattern formation process)
In the phase shift film pattern forming step, in the method of manufacturing the phase shift mask of the embodiment 2-1, first, the phase shift film 30 is etched using the resist film pattern as a mask to form the phase shift film pattern. On the other hand, in the manufacturing method of the phase shift mask of the embodiment 2-2, the light shielding film 45 is etched using the resist film pattern as a mask to form the light shielding film pattern, and then the phase shift is performed using the light shielding film pattern as a mask. The film 30 is etched to form a phase shift film pattern.
The etching medium (etching solution, etching gas) for etching the phase shift film 30 can selectively etch each of the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 constituting the phase shift film 30. There is no particular limitation.
Specifically, for example, as an etchant for wet etching a metal silicide-based material, at least one fluorine compound selected from hydrofluoric acid, hydrosilicofluoric acid, and ammonium hydrogen fluoride, hydrogen peroxide, An etching solution containing at least one oxidizing agent selected from nitric acid and sulfuric acid, and an etching solution containing at least one oxidizing agent selected from hydrogen peroxide, ammonium fluoride, phosphoric acid, sulfuric acid, and nitric acid. Can be mentioned. More specifically, an etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water can be used. Examples of the etching gas for dry etching the metal silicide material layer include a fluorine-based gas and a chlorine-based gas. Examples of the fluorine-based gas include CF4 gas, CHF3 gas, SF6 gas, and those obtained by mixing O2 gas with these gases.
For example, as an etchant for wet-etching a chromium-based material, an etching solution containing ceric ammonium nitrate and perchloric acid, or an etching gas composed of a mixed gas of chlorine gas and oxygen gas can be given.
Thereafter, the resist film pattern is stripped using a resist stripping solution or by ashing.
In the manufacturing method of the phase shift mask of the embodiment 2-2, the light shielding film pattern may be removed by an etching medium for etching the light shielding film 45, or the phase shift film pattern has a size different from the phase shift film pattern size. In the case of forming a light shielding film pattern having a pattern size, after forming a resist film pattern on the light shielding film pattern again, a light shielding film pattern forming step is performed using the resist film pattern as a mask.

  Since the phase shift mask of the second embodiment includes the phase shift layer 31 and the metal layer 33 as the phase shift film 30, it satisfies the predetermined optical characteristics of the phase difference and the transmittance and is 365 nm or more. In the wavelength range of 436 nm or less, the transmittance wavelength dependency is excellent (within 5.5%). Furthermore, the phase shift mask blank 10 having the phase shift film 30 including the phase shift layer 31, the metal layer 33, and the reflectance reduction layer 32 satisfies the predetermined optical characteristics of the phase difference and the transmittance, and is 365 nm or more. In the wavelength range of 436 nm or less, the transmittance wavelength dependency is excellent (within 5.5%), the surface reflectance property is also excellent (10% or less), and the back surface reflectance property is also excellent. Moreover, it has the characteristic which can improve the resolution of the transfer pattern transcribe | transferred on a display apparatus board | substrate corresponding to the characteristic of a phase shift mask being excellent.

(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.
Hereinafter, each process will be described in detail.

(Installation process)
In the placing step (placement step), the phase shift mask manufactured in the second embodiment is placed (placed) on the mask stage of the exposure apparatus. Here, the phase shift mask is arranged so that the pattern formation surface side faces the resist film formed on the display device substrate via the projection optical system of the exposure apparatus.

(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 a resist film formed on the display device substrate. The exposure light is a composite light including a plurality of wavelengths selected from a wavelength range of 365 nm to 436 nm, a composite light including a plurality of wavelengths selected from a wavelength range of 313 nm to 436 nm, and a wavelength of 313 nm to 436 nm. This is monochromatic light that is selected by cutting a certain wavelength region from the region with a filter or the like. For example, the exposure light is composite light including i-line, h-line and g-line, mixed light including j-line, i-line, h-line and g-line, or i-line monochromatic light. When composite light is used as exposure light, the exposure light intensity can be increased to increase the throughput, so that the manufacturing cost of the display device can be reduced.
As shown in FIG. 3, the transmittance spectrum obtained in Example 1 has a characteristic that it bends in a region having a shorter wavelength than the ig line (the inclination becomes extremely steep). From this feature, there is an advantage that an action of a band cut filter that cuts light in a wavelength region shorter than the ig line can be obtained.

  According to the display device manufacturing method of the third embodiment, a high-resolution and high-definition display device can be manufactured. For example, a fine pattern (for example, a contact hole of 1.8 μm or a line and space pattern having a pattern line width of 1.8 μm) can be formed.

(Embodiment 4)
In the fourth embodiment, a specific example of the phase shift mask blank will be described.

  As described above, the present inventor, in the phase shift film composed of three laminated films, sequentially from the substrate side, a predetermined phase shift layer (for example, ZrSiO, ZrSiON, MoSiO, MoSiON, etc.) and a predetermined metal layer (For example, Cr, Zr, and Mo metals, and CrC, CrCN, CrCO, ZrC, ZrCN, ZrCO, MoC, MoCN, MoCO, etc. whose content of these metals is 55 atomic percent or more and less than 100 atomic percent) and predetermined By combining with a reflectance reduction layer (for example, CrO, CrOCN, CrON, ZrSiON, MoSiON, etc.), the predetermined transmittance wavelength dependency can be reduced (Function 1) (for example, within 5.5%). The surface reflectance can be reduced (function 2), and the surface reflectance can be reduced (for example, 10% or less). Function 3), can be controlled back surface reflectance can (be larger) (function 4), and found that it is possible to combine all. Further, when a phase shift mask is produced using the phase shift mask blank, a combination of materials having different etching selectivity between the phase shift layer and the metal layer, the phase shift layer, the metal layer, and the reflectance reduction layer When the material is a combination of materials with different etching selectivity, the metal layer, the metal layer, and the reflectance reduction layer formed on the phase shift layer have the function of an etching mask (hard mask), so CD variation is reduced. It has been found that it can also have (function 5).

As a typical example of the above, a phase shift film having a three-layer structure in which a phase shift layer made of ZrSiON / a metal layer made of Cr / a reflectance reduction layer made of CrON or CrCON is sequentially formed from the transparent substrate side. It is done. In addition, a phase shift film having a three-layer structure including a phase shift layer made of ZrSiON / a metal layer made of CrC / CrO, CrOCN, or a CrON reflectivity reduction layer in order from the transparent substrate side can be mentioned.
Based on these, embodiments in which the material of each layer is replaced with the materials listed above as materials that can be selected in each layer are included in the present invention.

  In the above-described three-layer phase shift film, when the phase shift layer is replaced from ZrSiON to MoSiON or MoSiN, the predetermined transmittance wavelength dependency (for example, within 5.5%) is about the same, but the wavelength is 365 nm. The transmittance is relatively reduced to about 3%. In this case, it is useful as a phase shift film having a low transmittance (for example, 1% to 3%). This will be described later.

  Further, in the above-described three-layer phase shift film, even when the reflectance reduction layer is replaced with CrO, CrOCN, or CrON from MoSiN, the predetermined transmittance wavelength dependency (for example, within 5.5%) is approximately the same. However, the transmittance decreases to 3% or less at a wavelength of 365 nm. On the other hand, even when the reflectivity-reducing layer is replaced with CrO, CrOCN, or CrON with ZrSiO, ZrSiON, MoSiO, MoSiON, by adjusting the oxygen content contained in the reflectivity-reducing layer and / or the thickness of the metal layer The predetermined transmittance wavelength dependency (for example, within 5.5%) is about the same, and the transmittance can be adjusted to 5% or more at a wavelength of 365 nm.

  Hereinafter, based on an Example and a comparative example, this invention is demonstrated more concretely. The following examples are merely examples of the present invention and do not limit the present invention.

Example 1
(Phase shift mask blank)
In Example 1, a phase shift mask blank having a configuration of QZ (transparent substrate) / ZrSiON / CrC / CrO will be described.
The phase shift film in the phase shift mask blank of Example 1 includes a phase shift layer (ZrSiON, film thickness 90 nm), a metal layer (CrC, film thickness 20 nm), and a reflectance reduction layer (CrO) arranged in order from the transparent substrate side. And a film thickness of 35 nm).
A synthetic quartz glass substrate (QZ) having a size of 800 mm × 920 mm and a thickness of 10 mm was used as the transparent substrate. Both main surfaces of the transparent substrate are mirror-polished. Both main surfaces of the transparent substrate used in the following examples and comparative examples are similarly mirror-polished.

The phase shift film in which the phase shift layer, the metal layer, and the reflectance reduction layer were laminated on the transparent substrate had a refractive index of 2.40 at a wavelength of 365 nm and an extinction coefficient of 0.436 at a wavelength of 365 nm.
In addition, the refractive index and extinction coefficient of the phase shift layer were measured using n & k Analyzer 1280 (trade name) manufactured by n & k Technology.

The content of each element in the phase shift layer (ZrSiON) was 22 atomic% for Zr, 22 atomic% for Si, 14 atomic% for O, and 42 atomic% for N.
The metal layer (CrC) had a Cr content of 95 atomic% and a C content of 5 atomic%.
As for the content of each element of the reflectance reduction layer (CrO), the Cr content was 70 atomic%, and the O content was 30 atomic%.
In addition, the content rate of each said element was measured by the X ray photoelectron spectroscopy (XPS). In the following Examples and Comparative Examples, the same apparatus was used for measuring the element content.

  Due to the three-layer structure described above, the phase shift film has a transmittance of 1.5% at a wavelength of 313 nm, 5.1% at a wavelength of 365 nm, 6.0% at a wavelength of 405 nm, and 413 nm. The wavelength was 6.0%, and the wavelength of 436 nm was 5.9%. Further, this phase shift film had a transmittance variation width (transmittance wavelength dependency) of 0.8% in a wavelength range of 365 nm to 436 nm.

  Due to the three-layer structure described above, the phase shift film has a phase difference of 181.1 ° at a wavelength of 365 nm, 151.5 ° at a wavelength of 405 nm, 147.2 ° at a wavelength of 413 nm, and 436 nm. The wavelength was 137.1 °. Further, this phase shift film had a phase difference fluctuation range of 44.0 ° in a wavelength range of 365 nm to 436 nm.

FIG. 4 shows the transmittance spectrum of the phase shift film of the phase shift mask crank according to the first embodiment.
The transmittance and the phase difference were measured using MPM-100 (trade name) manufactured by Lasertec. In the following examples and comparative examples, the same apparatus was used for measuring transmittance and phase difference. The transmittance values in the examples and comparative examples are all based on Air.

The phase shift film has a surface reflectance of 7.5% at a wavelength of 350 nm, 4.9% at a wavelength of 365 nm, 0.7% at a wavelength of 405 nm, and 0.3% at a wavelength of 413 nm. And 0.3% at a wavelength of 436 nm. Further, this phase shift film had a fluctuation range of surface reflectance of 4.6% in a wavelength range of 365 nm to 436 nm. Further, this phase shift film had a fluctuation range of the surface reflectance of 7.2% in a wavelength range of 350 nm to 436 nm.
The surface reflectance was measured by using So1idSpec-3700 (trade name) manufactured by Shimadzu Corporation. In the following examples and comparative examples, the same apparatus was used for measuring the surface reflectance.

The phase shift film had a back-surface reflectance of 8.1% at a wavelength of 365 nm, 45.0% at a wavelength of 405 nm, and 59.56% at a wavelength of 436 nm. Moreover, this phase shift film had a fluctuation range of the back surface reflectance of 51.3% in the wavelength range of 365 nm to 436 nm.
The back surface reflectance was measured using So1idSpec-3700 (trade name) manufactured by Shimadzu Corporation. In the following Examples and Comparative Examples, the same apparatus was used for measuring the back surface reflectance.

(Manufacture of phase shift mask blanks)
The 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.
Thereafter, the transparent substrate was carried into the sputtering chamber of the sputtering apparatus.
Thereafter, a spanter power of 5.0 kW is applied to a ZrSi target (Zr: Si = 1: 2) (atomic (%) ratio) disposed in the sputtering chamber, and a mixed gas of Ar gas, O 2 gas, and N 2 gas Was introduced into the sputtering chamber, and a 90 nm-thick phase shift layer made of ZrSiON was formed on the main surface of the transparent substrate. Here, the mixed gas was introduced into the sputtering chamber such that Ar had a flow rate of 50 sccm, O 2 had a flow rate of 5 sccm, and N 2 had a flow rate of 50 sccm.
Thereafter, a sputtering power of 2.0 kW is applied to the Cr target, and a mixed gas of Ar gas and CH4 gas (a mixed gas containing CH4 gas at a concentration of 2.5% in Ar gas) is placed in the sputtering chamber. While introducing, a 20 nm thick metal layer made of CrC was formed on the phase shift layer. Here, the mixed gas of Ar gas and CH4 gas was introduced into the sputtering chamber so as to have a flow rate of 150 sccm.
After that, while applying a sputtering power of 6.0 kW to the Cr target and introducing a mixed gas of Ar gas and O 2 gas into the sputtering chamber, a 35 nm-thickness reflectance reduction layer made of CrO is formed on the metal layer. did. Here, the mixed gas was introduced into the sputtering chamber so that the flow rate of Ar was 60 sccm and O 2 was 50 sccm.
Thereafter, a transparent substrate on which a phase shift film composed of a phase shift layer (ZrSiON, film thickness 90 nm), a metal layer (Cr, film thickness 20 nm), and a reflectance reduction layer (CrO, film thickness 35 nm) is formed is sputtered. Removed from the apparatus and cleaned.

(Manufacture of phase shift mask)
A phase shift mask was manufactured by the following method using the phase shift mask blank described above.
First, a resist film made of a novolac positive photoresist was formed on the phase shift film of the above-described phase shift mask blank.
Thereafter, a predetermined pattern (1.8 μm line and space pattern) was drawn on the resist film by using a laser beam having a wavelength of 413 nm by a laser drawing machine.
Thereafter, the resist film was developed with a predetermined developer to form a resist film pattern on the phase shift film. At this time, the deterioration of the roughness of the edge portion of the resist film pattern cross section, which seems to be caused by the standing wave, was not confirmed.
Thereafter, the phase shift film was etched using the resist film pattern as a mask to form a phase shift film pattern.
A chromium etching solution (an etching solution containing ceric ammonium nitrate and perchloric acid) was used as an etching solution for the metal layer and the reflectance reduction layer constituting the phase shift film.
An etching solution of zirconium silicide obtained by diluting a mixed solution of hydrogen peroxide, ammonium fluoride and phosphoric acid with pure water was used as an etching solution for the phase shift layer constituting the phase shift film.
At the stage where the etching is completed, the phase shift layer (ZrSiON) is side-etched more than the upper metal layer (CrC) and the reflectance reduction layer (CrO), resulting in a step. Therefore, with the resist film pattern remaining, the metal layer (Cr) and the reflectance reduction layer (CrO) are once again side-mounted with the chromium etching solution with the metal layer (CrC) and the reflectance reduction layer (CrO). Two-step etching was performed to eliminate the step between the two.
Thereafter, the resist film pattern was stripped using a resist stripping solution.

The phase shift film pattern cross section of the phase shift mask manufactured using the above-described phase shift mask blank was of a level that does not affect the mask characteristics.
In addition, the phase shift film pattern cross section of the phase shift mask was observed using an electron microscope (JSM7401F (trade name) manufactured by JEOL Ltd.). In the following examples and comparative examples, the same apparatus was used to observe the phase shift film pattern cross section.

The CD variation of the phase shift film pattern of the phase shift mask manufactured using the above-described phase shift mask blank was 50 nm, which was good. The CD variation is a deviation width from a target line-and-space pattern (line pattern width: 1.8 μm, space pattern width: 1.8 μm).
The CD variation in the phase shift film pattern of the phase shift mask was measured using SIR8000 manufactured by Seiko Instruments Nano Technology. In the following examples and comparative examples, the same apparatus was used for measuring CD variation of the phase shift film pattern.

  The above-described phase shift mask blank and phase shift mask satisfy exceptional optical characteristics of phase difference and transmittance, and in the wavelength range of 365 nm or more and 436 nm or less, are particularly excellent in transmittance wavelength dependency (1% In addition, the surface reflectance characteristics were excellent (4.9% or less) and the back surface reflectance characteristics were excellent (40% or more except 365 nm). In addition, the resolution of the transfer pattern transferred onto the display device substrate is improved in response to the excellent characteristics of the phase shift mask, and the line and space pattern having a pattern line width of 1.8 μm is transferred without causing a CD error. Confirmed that it has been. Note that the pattern transfer process using the phase shift mask in the manufacturing process of the display device is a projection exposure of the same magnification exposure with a numerical aperture (NA) of 0.1, and the exposure light is i-line, h-line and g-line. It was set as the composite light containing. Thereafter, the manufacturing process of the display device in Examples 2 to 4 and Comparative Example 1 was performed under these exposure conditions.

(Example 2)
(Phase shift mask blank)
In Example 2, a phase shift mask blank having a configuration of QZ / MoSiON / CrC / CrO will be described.
In Example 2, the material and film thickness of the phase shift layer and the film thickness of the metal layer are different from the phase shift mask blank of Example 1.
The phase shift film in the phase shift mask blank of Example 2 includes a phase shift layer (MoSiON, film thickness of 135 nm), a metal layer (CrC, film thickness of 10 nm), and a reflectance reduction layer (CrO) arranged in order from the transparent substrate side. And a film thickness of 35 nm).

  The phase shift film in which the phase shift layer, the metal layer, and the reflectance reduction layer were laminated on the transparent substrate had a refractive index of 2.40 at a wavelength of 365 nm and an extinction coefficient of 0.515 at a wavelength of 365 nm.

The content of each element in the phase shift layer (MoSiON) was 30 atomic% for Mo, 20 atomic% for Si, 20 atomic% for O, and 30 atomic% for N.
Values of Cr content and C content of the metal layer (CrC) are the same as those in Example 1.
Values of Cr content and O content of the reflectance reduction layer (CrO) are the same as those in Example 1.

Due to the above-described three-layer structure, the phase shift film has a transmittance of 1.3% at a wavelength of 313 nm, 3.1% at a wavelength of 365 nm, 5.1% at a wavelength of 405 nm, and at a wavelength of 413 nm. 5.5% and 6.4% at a wavelength of 436 nm. Further, this phase shift film had a transmittance fluctuation range (transmittance wavelength dependency) of 3.4% in a wavelength range of 365 nm to 436 nm.
Although the transmittance is lower than that of Example 1 (3.1% at a wavelength of 365 nm), the transmittance wavelength dependency is small, so that the resolution is good.
FIG. 5 shows the transmittance spectrum of the phase shift film of the phase shift mask crank according to the second embodiment.

  Due to the above-described three-layer structure, the phase shift film has a phase difference of 180.9 ° at a wavelength of 365 nm, 160.6 ° at a wavelength of 405 nm, 156.5 ° at a wavelength of 413 nm, and 436 nm. The wavelength was 145.5 °. Further, this phase shift film had a phase difference fluctuation range of 35.3 ° in a wavelength range of 365 nm to 436 nm.

  The phase shift film has a surface reflectance of 7.3% at a wavelength of 350 nm, 5.7% at a wavelength of 365 nm, 3.4% at a wavelength of 405 nm, and 3.2% at a wavelength of 413 nm. It was 3.7% at a wavelength of 436 nm. Further, this phase shift film had a fluctuation range of the surface reflectance of 2.1% in a wavelength range of 365 nm to 436 nm. Further, this phase shift film had a fluctuation range of the surface reflectance of 4.1% in a wavelength region of 350 nm to 436 nm.

  The phase shift film had a back surface reflectance of 20% or more in a wavelength range of 365 nm to 436 nm.

(Manufacture of phase shift mask blanks)
In Example 2, a sputtering power of 5.0 kW was applied to the MoSi target (Mo: Si = 1: 4) (atomic (%) ratio) during the formation of the phase shift layer, and Ar gas, O 2 gas, and N 2 gas were applied. A phase shift layer made of MoSiON and having a film thickness of 135 nm was formed on the main surface of the transparent substrate. Here, Ar gas was introduced into the sputtering chamber so that the flow rate was 60 sccm, O 2 was 40 sccm, and N 2 was 50 sccm.
The phase shift mask blank of Example 2 was manufactured by the same method as Example 1 except for the other points.

(Manufacture of phase shift mask)
In Example 2, a molybdenum silicide etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water at the time of etching the phase shift layer was used.
In other respects, the phase shift mask of Example 2 was manufactured in the same manner as in Example 1.

  The CD variation of the phase shift film pattern of the phase shift mask manufactured using the above-described phase shift mask blank was 56 nm, which was favorable.

  The phase shift mask blank and the phase shift mask described above satisfy the predetermined optical characteristics of the phase difference and the transmittance, and are excellent in transmittance wavelength dependency in the wavelength range of 365 nm to 436 nm (3.3%). In addition, the surface reflectance characteristics were excellent (5.7% or less), and the back surface reflectance characteristics were also excellent (20% or more). Corresponding to the excellent characteristics of the phase shift mask, positional displacement during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line and space pattern was transferred without causing a CD error.

(Example 3)
(Phase shift mask blank)
In Example 3, a phase shift mask blank having a configuration of QZ / MoSiN / CrC / CrO will be described.
In Example 3, the material and film thickness of the phase shift layer and the film thickness of the metal layer are different from the phase shift mask blank of Example 2.
The phase shift film in the phase shift mask blank of Example 3 includes a phase shift layer (MoSiN, film thickness 85 nm), a metal layer (CrC, film thickness 5 nm), and a reflectance reduction layer (CrO) arranged in this order from the transparent substrate side. And a film thickness of 35 nm).

  The phase shift film in which the phase shift layer, the metal layer, and the reflectance reduction layer were laminated on the transparent substrate had a refractive index of 2.40 at a wavelength of 365 nm and an extinction coefficient of 0.436 at a wavelength of 365 nm.

The content of each element in the phase shift layer (MoSiN) was 10 atomic% for Mo, 30 atomic% for Si, and 60 atomic% for N.
The value of the Cr content of the metal layer (Cr) is the same as in Example 2.
Values of Cr content and O content of the reflectance reduction layer (CrO) are the same as those in Example 2.

Due to the above-described three-layer structure, the phase shift film has a transmittance of 1.0% at a wavelength of 313 nm, 2.7% at a wavelength of 365 nm, 4.4% at a wavelength of 405 nm, and at a wavelength of 413 nm. 4.8% and 5.7% at a wavelength of 436 nm. Further, this phase shift film had a transmittance variation width (transmittance wavelength dependency) of 3.0% in a wavelength region of 365 nm to 436 nm.
Although the transmittance is lower than that of Example 2 (2.7% at a wavelength of 365 nm), the transmittance wavelength dependency is small, so that the resolution is good.
FIG. 6 shows the transmittance spectrum of the phase shift film of the phase shift mask crank of Example 3.

  Due to the three-layer structure described above, the phase shift film has a phase difference of 181.7 ° at a wavelength of 365 nm, 162.1 ° at a wavelength of 405 nm, 158.4 ° at a wavelength of 413 nm, and 436 nm. The wavelength was 148.7 °. Further, this phase shift film had a phase difference variation width of 32.9 ° in a wavelength range of 365 nm to 436 nm.

  The phase shift film has a surface reflectance of 9.3% at a wavelength of 350 nm, 7.9% at a wavelength of 365 nm, 5.5% at a wavelength of 405 nm, and 5.2% at a wavelength of 413 nm. It was 4.8% at a wavelength of 436 nm. Further, this phase shift film had a fluctuation range of surface reflectance of 3.1% in a wavelength range of 365 nm to 436 nm. Further, this phase shift film had a fluctuation range of the surface reflectance of 4.6% in a wavelength region of 350 nm to 436 nm.

  The phase shift film had a back surface reflectance of 20% or more in a wavelength range of 365 nm to 436 nm.

(Manufacture of phase shift mask blanks)
In Example 3, 5.6 kW of sputtering power was applied to the MoSi target (Mo: Si = 1: 4) (atomic (%) ratio) during the formation of the phase shift layer, and mixing of Ar gas and N 2 gas was performed. While introducing the gas into the sputtering chamber, a 85 nm thick phase shift layer made of MoSiN was formed on the main surface of the transparent substrate. Here, Ar gas was introduced into the sputtering chamber so that the flow rate was 40 sccm and N 2 was 60 sccm.
In other respects, the phase shift mask blank and the phase shift mask of Example 3 were manufactured in the same manner as in Example 2.

  The CD variation of the phase shift film pattern of the phase shift mask manufactured using the above-described phase shift mask blank was 60 nm, which was favorable.

  The phase shift mask blank and the phase shift mask described above satisfy the predetermined optical characteristics of the phase difference and the transmittance, and are excellent in transmittance wavelength dependency in the wavelength range of 365 nm to 436 nm (3.0%). In addition, the surface reflectance characteristics were excellent (7.9% or less), and the back surface reflectance characteristics were also excellent (20% or more). Corresponding to the excellent characteristics of the phase shift mask, positional displacement during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line and space pattern was transferred without causing a CD error.

Example 4
In the fourth embodiment, a phase shift mask blank having a ZrSiON / Cr phase shift film and a MoSi light shielding film on QZ will be described.
Example 4 is different from the phase shift mask blank of Example 1 in that a phase shift film without a reflectance reduction layer is formed and a light shielding film made of a MoSi-based material having an antireflection function is formed on the phase shift film. .
The phase shift film in the phase shift mask blank of Example 4 is composed of a phase shift layer (ZrSiON, film thickness 130 nm) and a metal layer (Cr, film thickness 10 nm), which are sequentially arranged from the transparent substrate side. The MoSi-based light-shielding film formed on the phase shift film was a light-shielding film having an antireflection function made of MoSiN (film thickness 25 nm) / MoSi (film thickness 65 nm) / MoSiON (film thickness 25 nm).

The phase shift film has a transmittance of about 5.1% at a wavelength of 365 nm due to the two-layer structure described above, and the phase shift film has a transmittance fluctuation range (transmittance wavelength dependency) of 365 nm to 436 nm. It was within 5.5% in the wavelength range.
Further, in the phase shift mask blank of Example 4, the film surface reflectance of the light shielding film has 10% or less at the wavelength of 413 nm of the laser drawing light, and the back surface reflectance of the phase shift film is 365 nm to 436 nm. It was 20% or more in the wavelength region.

  The phase shift film had a phase difference in the range of 160 ° to 200 ° at a wavelength of 365 nm due to the above-described two-layer structure.

  The CD variation of the phase shift film pattern of the phase shift mask manufactured using the above-described phase shift mask blank was 62 nm, which was favorable.

  The above-described phase shift mask blank and phase shift mask satisfy the predetermined optical characteristics of phase difference and transmittance, and are excellent in transmittance wavelength dependency within a wavelength range of 365 nm to 436 nm (within 5.5%). ) As well as excellent back surface reflectance characteristics (20% or more). Corresponding to the excellent characteristics of the phase shift mask, positional displacement during pattern transfer is suppressed, the resolution of the transfer pattern transferred onto the display device substrate is improved, and the pattern line width is 1.8 μm. It was confirmed that the line and space pattern was transferred without causing a CD error.

(Comparative Example 1)
The phase shift film in the phase shift mask blank of Comparative Example 1 is composed of only a phase shift layer (CrOCN, film thickness 122 nm). The phase shift mask blank of Comparative Example 1 is different from the phase shift mask blank of the above-described example in that the phase shift film does not include a metal layer and a reflectance reduction layer.
The phase shift film in the phase shift mask blank of Comparative Example 1 was formed under the following film formation conditions.
The content of each element in the phase shift film (CrOCN) was 44 atomic% for Cr, 8 atomic% for C, 30 atomic% for O, and 18 atomic% for N.
The transmittance of the phase shift film was 4.6% at a wavelength of 365 nm, 8.0% at a wavelength of 405 nm, and 11.0% at a wavelength of 436 nm. Further, this phase shift film had a transmittance fluctuation range (transmittance wavelength dependency) of 6.4% in a wavelength range of 365 nm to 436 nm.
The phase shift film has a phase difference of 179.6 ° at a wavelength of 365 nm, 164.7 ° at a wavelength of 405 nm, 161.7 ° at a wavelength of 413 nm, and 436 nm due to the single-layer structure described above. It was 153.1 ° in wavelength. Further, this phase shift film had a phase difference fluctuation range of 26.5 ° in a wavelength range of 365 nm to 436 nm.
The phase shift film has a surface reflectance of 24.0% at a wavelength of 365 nm, 25.1% at a wavelength of 405 nm, 25.3% at a wavelength of 413 nm, and 26.26 at a wavelength of 436 nm. 0%. Further, the phase shift film has a variation range of the surface reflectance of 2.0% in a wavelength range of 365 nm to 436 nm.
The phase shift film had a back surface reflectance of 17.9% at a wavelength of 365 nm, 19.9% at a wavelength of 405 nm, and 20.3% at a wavelength of 436 nm. Further, the fluctuation range of the back surface reflectance of the phase shift film was 2.4% in the wavelength range of 365 nm to 436 nm.

(Manufacture of phase shift mask blanks)
The phase shift mask blank of Comparative Example 1 was manufactured by the following method.
First, a synthetic quartz glass substrate, which is a transparent substrate, was prepared.
Thereafter, the transparent substrate was carried into the sputtering chamber of the sputtering apparatus.
Thereafter, a sputtering power of 3.5 kW is applied to the chromium target disposed in the sputtering chamber, and a mixed gas of Ar gas, N 2 gas, and CO 2 gas is introduced into the sputtering chamber, and a phase shift film having a film thickness of 122 nm made of CrOCN Was deposited. Here, the mixed gas was introduced into the sputtering chamber such that Ar had a flow rate of 46 sccm, N 2 had a flow rate of 32 sccm, and CO 2 had a flow rate of 18.5 sccm.
Thereafter, the transparent substrate on which the phase shift film was formed was taken out of the sputtering apparatus and washed.

(Manufacture of phase shift mask)
A phase shift mask was manufactured by the following method using the phase shift mask blank described above.
First, a resist film made of a novolac positive photoresist was formed on the phase shift film of the above-described phase shift mask blank.
Thereafter, a predetermined pattern (1.8 μm line and space pattern) was drawn on the resist film by using a laser beam having a wavelength of 413 nm by a laser drawing machine. Thereafter, the resist film was developed with a predetermined developer to form a resist film pattern on the phase shift film.
Then, using the resist film pattern as a mask, the phase shift film is etched with a chromium etching solution containing ceric ammonium nitrate and perchloric acid to form a phase shift film pattern, and then using a resist stripping solution, The resist film pattern was peeled off.
The CD variation of the phase shift film pattern of the phase shift mask manufactured using the above-described phase shift mask blank is 90 nm, which is a level required for the phase shift mask used for manufacturing a high-resolution, high-definition display device. It was not reached.
Since the phase shift mask according to Comparative Example 1 described above has a large CD variation and the film surface reflectance of the phase shift film pattern with respect to the exposure light is high, a high-resolution and high-definition display using the above-described phase shift mask. The device could not be manufactured.

  As mentioned above, although this invention was demonstrated in detail based on embodiment and an Example, this invention is not limited to this. It is obvious that those having ordinary knowledge in the relevant field can make modifications and improvements within the technical idea of the present invention.

  10 phase shift mask blank, 20 transparent substrate, 30 phase shift film, 31 phase shift layer, 32 reflectance reduction layer, 33 metal layer, 40 light shielding film pattern, 45 light shielding film, 46 light shielding layer, 47 surface reflectance reduction layer

Claims (14)

In the phase shift mask blank for display device manufacture,
A transparent substrate, and a phase shift film formed on the transparent substrate,
The phase shift film is composed of two or more laminated films,
The phase shift film mainly includes a phase shift layer having a function of adjusting a transmittance and a phase difference with respect to exposure light, and a metal layer having a function of adjusting a transmittance wavelength dependency in a wavelength range of 365 nm to 436 nm. Have
The phase shift film has predetermined optical characteristics in which the transmittance and phase difference of the phase shift film with respect to exposure light have predetermined optical characteristics,
The phase shift layer is made of a material containing at least one of metal, silicon, nitrogen and oxygen,
The metal layer is composed of a metal material or a metal and at least one of carbon, fluorine, nitrogen, and oxygen, and the metal content is 55 atomic% or more and less than 100 atomic%. Made of compound materials,
The phase shift film has a transmittance wavelength dependency within a wavelength range of 365 nm or more and 436 nm or less within 5.5%. In the phase shift mask blank for display device manufacture,
A transparent substrate, and a phase shift film formed on the transparent substrate,
The phase shift film is arranged mainly on the phase shift layer having a function of adjusting the transmittance and phase difference with respect to the exposure light, and the light incident on the surface side of the phase shift film. A reflectance reduction layer having a function of reducing the reflectance with respect to the liquid crystal, and a function of adjusting the transmittance wavelength dependency in a range of wavelengths from 365 nm to 436 nm, which is disposed between the phase shift layer and the reflectance reduction layer. Having a metal layer,
Due to the laminated structure of the phase shift layer, the metal layer, and the reflectance reduction layer, the transmittance and phase difference of the phase shift film with respect to exposure light have predetermined optical characteristics,
The phase shift layer is made of a material containing at least one of metal, silicon, nitrogen and oxygen,
The metal layer is composed of a metal material or a metal and at least one of carbon, fluorine, nitrogen, and oxygen, and the metal content is 55 atomic% or more and less than 100 atomic%. Made of compound materials,
The phase shift mask blank according to claim 1, wherein the phase shift film has a transmittance wavelength dependency within 5.5% in a wavelength range of 365 nm to 436 nm.   2. The phase shift film according to claim 1, wherein a surface reflectance of the phase shift film with respect to light incident from a surface side of the phase shift film is 10% or less in a wavelength region of 365 nm to 436 nm. 2. The phase shift mask blank according to 2.   4. The phase shift film according to claim 2, wherein the phase shift film has a surface reflectance of 15% or less in a wavelength region of 350 nm to 436 nm with respect to light incident from the phase shift film side. 5. The described phase shift mask blank.   The back surface reflectance of the said phase shift film with respect to the light which injects from the back surface side of the said transparent substrate is 20% or more in a wavelength range of 365 nm-436 nm, It is any one of Claim 1 to 4 characterized by the above-mentioned. Phase shift mask blank.   The reflectance reduction layer is made of a metal and a material containing at least one of nitrogen, oxygen and carbon, or a material containing a metal and silicon and at least one of nitrogen, oxygen and carbon. A phase shift mask blank according to any one of claims 2 to 5.   The phase shift mask blank according to any one of claims 1 to 6, wherein the metal constituting the metal layer is any one of Cr, Zr, Mo, Ti, Ta, and W.   The phase shift mask blank according to any one of claims 1 to 7, wherein the metal constituting the phase shift layer is any one of Zr, Mo, Ti, Ta, and W.   9. The phase shift mask according to claim 2, wherein the metal constituting the reflectance reduction layer is any one of Cr, Zr, Mo, Ti, Ta and W. blank.   The phase shift mask blank according to claim 1, further comprising a light shielding film formed on the phase shift film.   11. The phase according to claim 10, wherein the light shielding film has a film surface reflectance of 15% or less in a wavelength region of 350 nm to 436 nm with respect to light incident from a surface side of the light shielding film. Shift mask blank. In a method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the phase shift film of the phase shift mask blank according to any one of claims 1 to 9, and drawing using a laser beam having any wavelength selected from a wavelength range of 350 nm to 436 nm A step of forming a resist film pattern by processing and development processing;
And a step of etching the phase shift film with the resist film pattern as a mask to form a phase shift film pattern. In a method of manufacturing a phase shift mask for manufacturing a display device,
A resist film is formed on the light-shielding film of the phase shift mask blank according to claim 10 or 11, and a drawing process using a laser beam having any wavelength selected from a wavelength range of 350 nm to 436 nm, and development A step of forming a resist film pattern by processing;
Etching the light shielding film using the resist film pattern as a mask to form a light shielding film pattern;
Forming a phase shift film pattern by etching the phase shift film using the light shielding film pattern as a mask. In the manufacturing method of the display device,
The phase shift mask which arrange | positions the phase shift mask obtained by the manufacturing method of the phase shift mask of Claim 12 or 13 facing the said resist film with respect to the board | substrate with a resist film in which the resist film was formed on the board | substrate. Mask placement process;
and a pattern transfer step of transferring the phase shift film pattern by irradiating the phase shift mask with composite exposure light including i-line, h-line, and g-line.

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