JP2016045233A - Phase shift mask blank and method for manufacturing the same, and method for manufacturing the phase shift mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase shift mask blank capable of patterning a phase shift film in a cross-sectional shape in which a phase shift effect is sufficiently exhibited, by wet etching, and a method for manufacturing such the phase shift mask blank, and also to provide a method for manufacturing a phase shift mask having a phase shift film pattern capable of sufficiently exhibiting the phase shift effect.SOLUTION: A phase shift mask blank 1 has a structure in which a phase shift film 3 comprising a metal, silicon, and oxygen and/or nitrogen is formed on a transparent substrate 2. The phase shift film 3 has a main layer 3a and an outermost surface layer 3b which are made of the same materials. The refractive index at the wavelength 365 nm of the main layer upper part on a side of the outermost surface layer 3b is smaller than the refractive index at the wavelength 365 nm of the main layer lower part on a side of the transparent substrate 2.SELECTED DRAWING: Figure 1

Description

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

  Currently, there are a VA (Vertical alignment) method and an IPS (In Plane Switching) method as a method adopted in a liquid crystal display device. By these methods, a high-definition, high-speed display performance and wide viewing angle liquid crystal display device is realized. In the liquid crystal display device to which these methods are applied, the response speed and the viewing angle can be improved by forming the pixel electrode with a line and space pattern using a transparent conductive film. Recently, in order to further improve the response speed and viewing angle, improve the light utilization efficiency of the liquid crystal display device, that is, reduce the power consumption of the liquid crystal display device and improve the contrast, the pitch width of the line and space pattern is fine. Is required. For example, it is desired to reduce the pitch width of the line-and-space pattern (the total of the line width L and the space width S) from 6 μm to 5 μm, and further from 5 μm to 4 μm. In this case, at least one of the line width L and the space width S is often less than 3 μm. For example, there are many cases where L <3 μm, or L ≦ 2 μm, or S <3 μm, or S ≦ 2 μm.

  In manufacturing a liquid crystal display device or an organic EL display device, an 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, in the case of a thin film transistor (“TFT”) used in these display devices, a contact hole formed in a passivation (insulating layer) among a plurality of patterns constituting the TFT penetrates the insulating layer. The structure which conducts to the connecting portion on the lower layer side is adopted. At this time, if the patterns on the upper layer side and the lower layer side are accurately positioned and the shape of the contact hole is not reliably formed, correct operation of the display device cannot be guaranteed. Also in this case, it is necessary to increase the integration of device patterns as well as to improve the display performance, and there is a demand for pattern miniaturization. That is, the diameter of the hole pattern is required to be less than 3 μm. For example, a hole pattern with a diameter of 2.5 μm or less and further with a diameter of 2.0 μm or less is required, and in the near future, formation of a pattern with a diameter of 1.5 μm or less, which is less than this, is considered desirable.

  From such a background, for example, a photomask for manufacturing a display device that can cope with miniaturization of a line and space pattern and a contact hole 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 line and space patterns and contact holes, for example, a phase shift mask has attracted attention as a photomask for manufacturing a display device.

Recently, a phase shift mask having a chromium phase shift film has been developed as a photomask for manufacturing a liquid crystal display device.
In Patent Document 1, a transparent substrate, a light shielding layer formed on the transparent substrate, and a phase difference of 180 degrees with respect to any light in a wavelength region of 300 nm to 500 nm formed around the light shielding layer. A halftone phase shift mask is described that includes a phase shift layer made of a chromium oxynitride-based material that can be provided. In this phase shift mask, the light shielding layer on the transparent substrate is patterned, the phase shift layer is formed on the transparent substrate so as to cover the light shielding layer, the photoresist layer is formed on the phase shift layer, and the photoresist layer is formed. A resist pattern is formed by exposure and development, and the phase shift layer is patterned using the resist pattern as an etching mask.

JP 2011-13283 A

  The present inventors diligently studied a phase shift mask provided with a chromium phase shift film. As a result, when the chromium phase shift film is patterned by wet etching using the resist pattern as a mask, the wet etching solution penetrates into the interface between the resist film and the chromium phase shift film, and the etching of the interface portion proceeds quickly. I understood. The cross-sectional shape of the edge portion of the formed chromium-based phase shift film pattern is a tapered shape with an inclination and a skirt.

  When the cross-sectional shape of the edge portion of the chromium-based phase shift film pattern is a taper shape, the phase shift effect is reduced as the film thickness of the edge portion of the chromium-based phase shift film pattern decreases. For this reason, a phase shift effect cannot fully be exhibited. The penetration of the wet etching solution into the interface between the resist film and the chromium phase shift film is caused by poor adhesion between the chromium phase shift film and the resist film. For this reason, it is difficult to strictly control the cross-sectional shape of the edge portion of the chromium-based phase shift film pattern, and it is very difficult to control the line width (CD).

  Furthermore, the present inventors diligently studied a method for verticalizing the cross-sectional shape of the edge portion of the phase shift film pattern in order to solve these problems. Up to now, a method of inclining the film composition (eg, nitrogen content) of the phase shift film to change the etching rate in the film thickness direction, or adding an additive (eg, Al, Ga) to the phase shift film A method for controlling the etching time has been developed. However, with these methods, it has been very difficult to realize the uniformity of transmittance over the entire large-area phase shift mask.

  For this reason, the present invention has been made in view of the above-described problems, and a phase shift mask blank capable of patterning a phase shift film into a cross-sectional shape that can sufficiently exhibit a phase shift effect by wet etching, and its manufacture. It is an object of the present invention to provide a method and a method of manufacturing a phase shift mask having a phase shift film pattern that can sufficiently exhibit the phase shift effect.

(Configuration 1)
A phase shift mask blank in which a phase shift film containing metal, silicon, oxygen and / or nitrogen is formed on a transparent substrate, the phase shift film comprising a main layer made of the same material, an outermost surface And a refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side is smaller than a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side. Mask blank.

(Configuration 2)
The phase shift mask blank according to Configuration 1, wherein a difference (Δn) between a refractive index at a wavelength of 365 nm below the main layer and a refractive index at a wavelength of 365 nm above the main layer is −0.01 or less.

(Configuration 3)
The phase shift mask blank according to Configuration 1, wherein a difference (Δn) between a refractive index at a wavelength of 365 nm above the main layer and a refractive index at a wavelength of 365 nm below the main layer is −0.10 or less.

(Configuration 4)
4. The phase shift mask blank according to any one of Configurations 1 to 3, wherein a refractive index at a wavelength of 365 nm above the main layer is 2.50 or more.

(Configuration 5)
5. The phase shift mask blank according to any one of Configurations 1 to 4, wherein an etching mask film is formed on the phase shift film.

(Configuration 6)
6. The phase shift mask blank according to Configuration 5, wherein the etching mask film has a light shielding film having a light shielding function.

(Configuration 7)
The phase shift mask blank according to Configuration 5 or Configuration 6, wherein the etching mask film is made of a material containing chromium.

(Configuration 8)
The phase shift mask blank according to any one of Configurations 1 to 7, wherein the phase shift mask blank is an original for producing a phase shift mask by wet etching.

(Configuration 9)
A phase shift mask blank manufacturing method for forming a phase shift film containing a metal, silicon, oxygen and / or nitrogen on a transparent substrate by a sputtering method using an in-line type sputtering apparatus, on the transparent substrate, A film forming step of forming the phase shift film having a main layer and an outermost surface layer made of the same material, wherein the film forming step uses a metal silicide sputter target containing metal and silicon, In the latter half of the film formation of the phase shift film, an atmosphere containing a larger amount of the active gas than in the first half of the film formation is supplied, and the reactive sputtering is performed by a mixed gas containing an inert gas and the active gas. A method of manufacturing a phase shift mask blank.

(Configuration 10)
An active gas that oxidizes and / or nitrides the phase shift film is supplied from the downstream side to the sputter target in the transport direction of the transparent substrate in the vicinity of the sputter target, thereby forming the first half of the film formation in the second half of the film formation. The manufacturing method of the phase shift mask blank of the structure 9 characterized by setting it as atmosphere containing more active gas.

(Configuration 11)
The flow rate of the active gas is adjusted so that the refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side is smaller than the refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side. The manufacturing method of the phase shift mask blank of the structure 9 to do.

(Configuration 12)
Active so that a difference (Δn) between a refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side and a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side is −0.01 or less. The method of manufacturing a phase shift mask blank according to any one of Configurations 9 to 11, wherein the flow rate of the gas is adjusted.

(Configuration 13)
Active so that a difference (Δn) between a refractive index at a wavelength of 365 nm at the uppermost main layer on the outermost surface layer side and a refractive index at a wavelength of 365 nm at the lower lower layer on the transparent substrate side is −0.10 or less. The method of manufacturing a phase shift mask blank according to any one of Configurations 9 to 11, wherein the flow rate of the gas is adjusted.

(Configuration 14)
14. The structure according to claim 9, further comprising a film forming process for forming an etching mask film on the phase shift film after the film forming process for forming the phase shift film. A method of manufacturing a phase shift mask blank.

(Configuration 15)
Using the phase shift mask blank according to any one of Configurations 1 to 8 or the phase shift mask blank produced by the manufacturing method according to any of Configurations 9 to 14, the phase shift film is patterned by wet etching. A method of manufacturing a phase shift mask for producing a phase shift mask.

  According to the phase shift mask blank of the present invention, the phase shift film composed of the metal silicide material is formed. This phase shift film has a main layer made of substantially the same material and an outermost surface layer. The refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side is the main layer on the transparent substrate side. It is smaller than the refractive index at the lower wavelength of 365 nm. In the phase shift mask blank having such a configuration, the phase shift film can be patterned into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect by wet etching. Since this phase shift mask blank can make the cross-sectional shape of the edge portion of the phase shift film pattern obtained by patterning the phase shift film into a cross-sectional shape that can sufficiently exhibit the phase shift effect, The resolution can be improved and a master for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics can be obtained.

  Further, according to the method of manufacturing a phase shift mask blank according to the present invention, a phase shift film made of a metal silicide material on a transparent substrate and having a main layer and an outermost surface layer made of the same material is inline type. A film forming step of forming a film by a sputtering method using a sputtering apparatus; In this film forming process, an active gas having a component that slows the wet etching rate of the phase shift film using a sputter target containing metal and silicon is added to the active gas from the first half of the film formation in the latter half of the phase shift film formation. Is carried out by reactive sputtering using a mixed gas containing the inert gas and the active gas. By such a manufacturing method, a phase shift mask blank capable of patterning (etching) the phase shift film into a cross-sectional shape that can sufficiently exhibit the phase shift effect can be manufactured. Since the cross-sectional shape of the edge portion of the phase shift film pattern can be a cross-sectional shape that can sufficiently exhibit the phase shift effect, it is possible to improve the resolution and pattern the phase shift film pattern with good CD characteristics. A phase shift mask blank can be manufactured.

  Moreover, according to the manufacturing method of the phase shift mask which concerns on this invention, a phase shift mask is manufactured using the phase shift mask blank mentioned above. For this reason, the phase shift mask which has a phase shift film pattern which can fully exhibit a phase shift effect can be manufactured. Since the phase shift film pattern can sufficiently exhibit the phase shift effect, it is possible to improve the resolution and manufacture a phase shift mask having a phase shift film pattern having good CD characteristics. This phase shift mask can cope with the miniaturization of line and space patterns and contact holes.

It is sectional drawing which shows the structure of the phase shift mask blank by Embodiment 1 of this invention. It is a schematic diagram which shows the in-line type | mold sputtering apparatus which can be used for film-forming of a phase shift mask blank. It is sectional drawing which shows the structure of the phase shift mask blank by Embodiment 2 of this invention. (A)-(e) is sectional drawing which shows each process of the manufacturing method of the phase shift mask by Embodiment 3 of this invention. (A)-(h) is sectional drawing which shows each process of the manufacturing method of the phase shift mask by Embodiment 4 of this invention. It is a figure which shows the refractive index in wavelength 190nm-1000nm with respect to the main layer upper part and main layer lower part of the phase shift film of the phase shift mask blank of Example 1. FIG. It is a figure which shows the refractive index in wavelength 190nm-1000nm with respect to the main layer upper part and main layer lower part of the phase shift film of the phase shift mask blank of the comparative example 1. 3 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of the phase shift film pattern of Example 1. 6 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Comparative Example 1. It is sectional drawing for demonstrating the cross-sectional angle in the cross section of the edge part of the phase shift film pattern of a phase shift mask. It is a figure which shows the refractive index in wavelength 190nm-1000nm with respect to the main layer upper part and main layer lower part of the phase shift film of the phase shift mask blank of Example 3. FIG. 6 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Example 3. It is a figure which shows the refractive index in wavelength 190nm-1000nm with respect to the main layer upper part and main layer lower part of the phase shift film of the phase shift mask blank of Example 4. FIG. 6 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Example 4. It is a figure which shows the relational characteristic of the difference ((DELTA) n) of the refractive index in wavelength 365nm of the main layer lower part with respect to the refractive index in wavelength 365nm in the upper part of the main layer of the phase shift film 3, and the cross-sectional angle of a phase shift film pattern cross section.

  Hereinafter, embodiments of the present invention will be specifically described 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.

<Embodiment 1>
In Embodiment 1, a phase shift mask blank for manufacturing a display device and a manufacturing method thereof will be described.
FIG. 1 is a cross-sectional view showing a configuration of a phase shift mask blank according to Embodiment 1 of the present invention, and FIG. 2 is a schematic view showing an in-line type sputtering apparatus that can be used for forming a phase shift mask blank.

  As shown in FIG. 1, the phase shift mask blank 1 of Embodiment 1 has a configuration in which a phase shift film 3 made of a metal silicide material is laminated on a transparent substrate 2.

The manufacturing method of the phase shift mask blank 1 of Embodiment 1 configured as described above includes a preparation step of preparing a transparent substrate and a film formation step of forming a phase shift film on the main surface of the transparent substrate by sputtering. (Hereinafter sometimes referred to as a phase shift film forming step).
Hereinafter, each process will be described in detail.

1. Preparation Step First, the transparent substrate 2 is prepared.
The material of the transparent substrate 2 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.

2. Next, as shown in FIG. 1, a phase shift film 3 made of a metal silicide material is formed on the transparent substrate 2 by a sputtering method using an in-line type sputtering apparatus.
In detail, a sputtering target containing a metal and silicon is used to apply a sputtering power, and an inert gas and an active gas that oxidizes and / or nitrides the phase shift film are supplied to the transparent substrate 2 in the vicinity of the sputtering target. Phase shift containing metal, silicon and oxygen and / or nitrogen by reactive sputtering with a mixed gas containing an inert gas and an active gas supplied from the downstream side to the sputtering target in the transport direction of A film forming process for forming the film 3 is performed.
Here, it does not matter whether the inert gas and the active gas supplied from the downstream side to the sputtering target are mixed before the supply. For example, the inert gas and the active gas may be mixed in advance at a predetermined flow rate, and the mixed gas may be supplied from one gas inlet, or the inert gas and the active gas at a predetermined flow rate may be supplied respectively. You may supply from a dedicated gas inlet.
Thereafter, an exposure step of exposing the phase shift film 3 to a gas atmosphere containing a component that slows the wet etching rate of the phase shift film 3 may be performed continuously after the film formation step without exposing the phase shift film 3 to the atmosphere. .

  The phase shift film 3 has a property of changing the phase of exposure light (phase shift effect). Due to this property, a predetermined phase difference is generated between the exposure light transmitted through the phase shift film 3 and the exposure light transmitted through only the transparent substrate 2. When the exposure light is composite light including light in the wavelength range of 300 nm or more and 500 nm or less, the phase shift film 3 is formed so as to generate a predetermined phase difference with respect to the light of the representative wavelength. For example, when the exposure light is composite light including i-line, h-line, and g-line, the phase shift film 3 causes a phase difference of 180 degrees with respect to any of i-line, h-line, and g-line. To form. Further, in order to exert the phase shift effect, for example, the phase difference of the phase shift film 3 in the i-line is set in a range of 180 degrees ± 10 degrees, and is preferably set to about 180 degrees. Further, the transmittance of the phase shift film 3 is preferably 1% or more and 20% or less at a representative wavelength of any of i-line, h-line, and g-line. Particularly preferably, the transmittance of the phase shift film 3 is preferably 3% or more and 10% or less at a representative wavelength of any of i-line, h-line, and g-line.

The metal silicide material constituting the phase shift film 3 may contain metal and silicon as long as it has a predetermined transmittance and phase difference with respect to exposure light, and further contains other elements. It doesn't matter. Other elements may be elements that can control the refractive index (n) and extinction coefficient (k) in exposure light, and are selected from at least one element selected from oxygen (O) and nitrogen (N). The As other elements, carbon (C) and fluorine (F) may be contained. For example, metal silicide oxide, metal silicide oxynitride, metal silicide nitride, metal silicide carbonitride, metal silicide oxycarbide, metal silicide oxynitride, and the like can be given. Further, from the viewpoint of pattern controllability by wet etching, the metal silicide material constituting the phase shift film 3 is a material containing a metal, silicon, and a component that slows the wet etching rate of the phase shift film 3. Is preferred. Examples of components that reduce the wet etching rate of the phase shift film 3 include nitrogen (N) and carbon (C). Examples of the metal include transition metals such as molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), and zirconium (Zr). Examples of the metal silicide material constituting the phase shift film 3 include metal silicide nitride, metal silicide oxynitride, metal silicide oxycarbide, metal silicide oxynitride, and metal silicide oxynitride. It is done. Specifically, molybdenum silicide (MoSi) nitride, tantalum silicide (TaSi) nitride, tungsten silicide (WSi) nitride, titanium silicide (TiSi) nitride, zirconium silicide (ZrSi) nitride, Molybdenum silicide oxynitride, tantalum silicide oxynitride, tungsten silicide oxynitride, titanium silicide oxynitride, zirconium silicide oxynitride, molybdenum silicide oxycarbide, tantalum silicide oxycarbide, titanium silicide Oxide carbide, tungsten silicide oxycarbide, zirconium silicide oxycarbide, molybdenum silicide carbonitride, tantalum silicide carbonitride, titanium silicide carbonitride, zirconium silicide Id carbonitrides, tungsten silicide carbonitrides, molybdenum silicides carbonitrides, tantalum silicides carbonitrides, titanium silicides carbonitrides, tungsten silicides carbonitrides, zirconium silicides Nitride is mentioned.
When the material constituting the phase shift film 3 is metal, silicon, or nitrogen, the composition is a desired phase difference (180 ° ± 20 °) with respect to exposure light, transmittance (1% to 20%), wet Adjustment is performed from the viewpoint of etching characteristics (cross-sectional shape of the phase shift film 3 pattern and CD variation) and chemical resistance. The ratio of metal to silicon is preferably metal: silicon = 1: 1 or more and 1: 9 or less. The nitrogen content is preferably 25 atom% or more and 55 atom% or less, more preferably 30 atom% or more and 50 atom% or less.

The film forming process of the phase shift film 3 uses a sputter target containing a metal and silicon, and includes a sputter containing a gas having components whose refractive index (n) and extinction coefficient (k) in exposure light can be controlled. Performed in a gas atmosphere. The sputtering gas atmosphere includes an inert gas and an active gas that oxidizes and / or nitrides the phase shift film. The active gas includes oxygen gas (O ₂ ), carbon monoxide gas (CO), carbon dioxide gas (CO ₂ ), nitrogen gas (N ₂ ), nitrogen monoxide gas (NO), and nitrogen dioxide gas (NO ₂ ). Nitrous oxide gas (N ₂ O), hydrocarbon gas (CH ₄ etc.), fluorocarbon gas (CF ₄ etc.), fluorine nitride gas (NF ₃ etc.) and the like. Further, from the viewpoint of pattern controllability by wet etching, the film forming process of the phase shift film 3 uses a sputtering target containing a metal and silicon, and has a gas having a component that slows the wet etching rate of the phase shift film 3. It is preferable to carry out in a sputtering gas atmosphere containing. Examples of the component that slows the wet etching rate of the phase shift film 3 include nitrogen (N) and carbon (C) as described above. As a gas having a component that slows the wet etching rate of the phase shift film 3, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, dinitrogen monoxide gas, carbon monoxide gas, carbon dioxide gas, hydrocarbon gas (CH ₄ ), active gases such as fluorine-containing gas (CF ₄ etc.), fluorine nitride-based gas (NF ₃ etc.). As the inert gas, helium gas, neon gas, argon gas, krypton gas, xenon gas and the like may be contained. The sputtering gas atmosphere is, for example, an inert gas including at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas, and a group consisting of nitrogen gas, nitrogen monoxide gas, and nitrogen dioxide gas. It consists of a mixed gas with an active gas containing at least one selected.

  After the phase shift film 3 is formed, an exposure step of exposing the phase shift film 3 to an exposure gas atmosphere containing a gas having a component that slows the wet etching rate of the phase shift film 3 may be performed. As a component that slows the wet etching rate of the phase shift film 3, as described above, for example, nitrogen (N) is cited. Examples of the gas having a component that slows the wet etching rate of the phase shift film 3 include an active gas such as nitrogen gas. In the gas atmosphere for exposure, helium gas, neon gas, argon gas, krypton gas, xenon gas, etc. may be contained as an inert gas. When the exposure gas atmosphere is a mixed gas atmosphere of nitrogen gas and inert gas, the ratio of nitrogen gas to inert gas (nitrogen gas / inert gas) is 20% or more, preferably 30% or more.

  The film thickness of the phase shift film 3 is appropriately adjusted in the range of 80 nm or more and 140 nm or less so that desired optical characteristics (phase difference) can be obtained.

As shown in FIG. 1, the phase shift film 3 is generally composed of a main layer 3a made of the same material and an outermost surface layer formed in the depth direction from the outermost surface of the main layer 3a by surface oxidation after film formation. 3b. The main layer 3a has a characteristic that the composition ratio of each element in the film depth direction is substantially uniform (at least it can be said that it is substantially uniform in the analysis result by X-ray photoelectron spectroscopy), and the phase of the phase shift film 3 It is a main body region of the phase shift film 3 that exhibits a shift effect. Further, when the etching mask film 4 is formed immediately after the phase shift film 3 is formed, or when the etching mask film 4 is continuously formed in vacuum after the phase shift film 3 is formed, the phase shift is performed. The outermost surface layer 3b is not formed between the film 3 and the etching mask film 4, and the phase shift film 3 is composed only of the main layer 3a.
The phase shift film 3 may be either a single layer film or a laminated film. When the phase shift film 3 is formed of a laminated film, the composition and composition ratio are matched between the interfaces of each layer, and the etching rate during wet etching is made constant, for example, so-called erosion in the cross section to be etched. It is preferable to prevent the occurrence of the phenomenon. In the case of a laminated film, it is preferable that the film forming process of the phase shift film 3 is performed a plurality of times under the same film forming conditions. The plurality of film forming steps are preferably performed continuously in the same in-line sputtering apparatus. When performing a plurality of film forming steps continuously, for example, an in-line type sputtering apparatus as described below is used. When the film forming process is performed a plurality of times, the sputtering power applied to the sputter target when forming the phase shift film 3 can be reduced.
The thickness of the outermost surface layer 3b is preferably, for example, 0.1 nm or more and 10 nm or less, but is not limited to this range.

Through the above-described phase shift film formation step, the refractive index at a wavelength of 365 nm of the upper part of the outermost surface layer 3b side (hereinafter sometimes referred to as the upper part of the main layer) of the main layer 3a of the phase shift film 3 is changed. Among these, the refractive index at a wavelength of 365 nm of the lower part on the transparent substrate 2 side (hereinafter sometimes referred to as the main layer lower part) can be made smaller. The phase shift film 3 having such a configuration can have a cross-sectional shape that can sufficiently exhibit the phase effect by patterning by wet etching.
In addition, the refractive index at a wavelength of 365 nm above the main layer is desirably 2.50 or more. Furthermore, the difference (Δn) between the refractive index at the wavelength of 365 nm at the lower part of the main layer and the refractive index at the wavelength of 365 nm at the upper part of the main layer is preferably −0.01 or less, more preferably −0.10 or less. . When the refractive index difference (Δn) at a wavelength of 365 nm exceeds −0.01, it may be difficult to obtain a cross-sectional shape that can exhibit the phase effect by patterning the phase shift film 3 by wet etching. Yes (when it is −0.10 or less, it is possible to obtain a cross-sectional shape almost perpendicular).
Note that the above-described phase shift film forming step makes the refractive index of the upper part of the main layer smaller than the refractive index of the lower part of the main layer at the measurement wavelength, not only at the wavelength of 365 nm but also in the wavelength range of 190 nm to 1000 nm. (See FIGS. 6, 11, and 13 to be described later).

In the main layer 3a of the phase shift film 3, as described above, the composition ratio of each element in the film depth direction is substantially uniform. Here, the composition ratio of each element in the film depth direction being substantially uniform means that the content of each element in the film depth direction of the phase shift film 3 obtained under the film formation conditions in the film formation step is the center. This means that the content of each element in the main layer 3a is within a predetermined range of fluctuation with respect to the central content. For example, it is ± 2.5 atomic% with respect to the central content of each element of metal, silicon, nitrogen, and oxygen.
Incidentally, the substantially uniform composition ratio of each element in the film depth direction in the main layer 3a of the phase shift film 3 is intended to give a stepwise or continuous composition change in the film thickness direction during the film forming process. In addition, it is also achieved by forming the phase shift film 3 without performing the operation of changing the supply method and supply amount of the sputtering raw material and sputtering gas.

  Such a phase shift film forming step can be performed using, for example, an inline-type sputtering apparatus 11 shown in FIG.

  The sputtering apparatus 11 is an inline type, and includes five chambers: a carry-in chamber LL, a first sputter chamber SP1, a buffer chamber BU, a second sputter chamber SP2, and a carry-out chamber ULL. These five chambers are arranged sequentially in sequence.

  The transparent substrate 2 mounted on the tray (not shown) has a carry-in chamber LL, a first sputter chamber SP1, a buffer chamber BU, a second sputter chamber SP2, and a carry-out chamber in the direction of arrow S at a predetermined carrying speed. It can be transported in the ULL order. In addition, the transparent substrate 2 mounted on the tray (not shown) has a discharge chamber ULL, a second sputtering chamber SP2, a buffer chamber BU, a first sputtering chamber SP1, and a loading chamber LL in a direction opposite to the arrow S. Can be put back in order.

A partition plate separates between the carry-in chamber LL and the first sputter chamber SP1 and between the second sputter chamber SP2 and the carry-out chamber ULL. The carry-in chamber LL and the carry-out chamber ULL can be partitioned from the outside of the sputtering apparatus 11 by a partition plate.
The carry-in chamber LL, the buffer chamber BU, and the carry-out chamber ULL are connected to an exhaust device (not shown) that performs exhaust.

In the first sputter chamber SP1, a first sputter target 13 containing metal and silicon for forming the phase shift film 3 is disposed on the carry-in chamber LL side, and the arrow of the transparent substrate 2 in the vicinity of the first sputter target 13 is disposed. A first gas introduction port GA11 is disposed at a position upstream of the first sputter target 13 in the transport direction indicated by S, and a second gas introduction port GA12 is disposed at a position downstream of the first sputter target 13. Has been placed. Further, in the first sputter chamber SP1, a second sputter target 14 containing metal and silicon for forming the phase shift film 3 is disposed on the buffer chamber BU side, and the transparent substrate 2 in the vicinity of the second sputter target 14 is disposed. The third gas introduction port GA21 is disposed at a position upstream of the second sputter target 14 in the transport direction indicated by the arrow S, and the fourth gas introduction port is disposed at a position downstream of the second sputter target 14. GA22 is arrange | positioned.
Here, the interval between the first sputter target 13 and the downstream second gas introduction port GA12 is set wider than the interval between the first sputtering target 13 and the first gas introduction port GA11 on the upstream side. This is because the sputter gas atmosphere is changed by providing a distance between the sputter target and the downstream gas inlet, as will be described later. Similarly, the distance between the second sputter target 14 and the fourth gas inlet GA22 on the downstream side is set wider than the distance between the second sputter target 14 and the third gas inlet GA21 on the upstream side. .
In the first sputtering chamber SP1, the distance between the sputtering target and the downstream gas introduction port is set to, for example, 15 cm or more and 50 cm or less, and the interval between the sputtering target and the upstream gas introduction port is, for example, 1 cm. It is preferably set to 5 cm or less.

In the second sputter chamber SP2, a third sputter target 15 containing metal and silicon for forming the phase shift film 3 is disposed on the buffer chamber BU side, and the arrow of the transparent substrate 2 in the vicinity of the third sputter target 15 is disposed. The fifth gas introduction port GA31 is disposed at a position upstream of the third sputter target 15 in the transport direction indicated by S, and the sixth gas introduction port GA32 is disposed at a position downstream of the third sputter target 15. Has been placed. Further, in the second sputter chamber SP2, a fourth sputter target 16 containing a metal and silicon for forming the phase shift film 3 is disposed on the carry-out chamber ULL side, and the transparent substrate 2 in the vicinity of the fourth sputter target 16 is disposed. The seventh gas inlet GA41 is disposed at a position upstream of the fourth sputter target 16 in the transport direction indicated by the arrow S, and the eighth gas inlet is positioned downstream of the fourth sputter target 16. GA42 is arranged.
Here, similarly to the first sputter chamber SP1, the distance between the third sputter target 15 and the sixth gas inlet GA32 on the downstream side is the distance between the third sputter target 15 and the fifth gas inlet GA31 on the upstream side. Is set wider than. Similarly, the interval between the fourth sputter target 16 and the downstream-side eighth gas introduction port GA42 is set wider than the interval between the fourth sputtering target 16 and the upstream-side seventh gas introduction port GA41. .
In the second sputter chamber SP2, as in the first sputter chamber SP1, the distance between the sputter target and the downstream gas inlet is set to, for example, 15 cm to 50 cm, and the sputter target and the upstream gas The distance from the introduction port is preferably set to 1 cm or more and 5 cm or less, for example.
In FIG. 2, the first sputter target 13, the second sputter target 14, the third sputter target 15, and the fourth sputter target 16 are hatched.

Here, the case of forming the phase shift film 3 made of a single layer film (one film formation) will be described.
First, the transparent substrate 2 mounted on a tray (not shown) is carried into the carry-in chamber LL of the sputtering apparatus 11.
Next, after the inside of the sputtering apparatus 11 is set to a predetermined degree of vacuum, for example, a sputtering gas having a predetermined flow rate is supplied from the second gas introduction port GA12 on the downstream side of the first sputtering target 13, and an inert gas and an active gas are supplied. The mixed gas is introduced into the first sputtering chamber SP1 and a predetermined sputtering power is applied to the first sputtering target 13. The application of the sputtering power and the introduction of the sputtering gas are continued until the transparent substrate 2 is transported to the unloading chamber ULL.
Due to the supply of the sputtering gas from the downstream side, the existence rate of the inert gas having a relatively long flight distance is increased on the upstream side of the chamber (a location far from the second gas introduction port GA12). It is considered that the atmosphere of the inert gas / rich sputtering gas in which the content of the active gas is larger than the predetermined content is obtained. Further, as the gas moves from the upper stream side to the lower stream side, the content of the inert gas gradually decreases to the predetermined content (the influence of the difference in the flight distance gradually disappears), resulting in a sputtering gas atmosphere. At a position close to the gas inlet GA12, it is considered that a sputtering gas atmosphere containing an inert gas and an active gas having a predetermined content is obtained. That is, the phase shift film is formed in an atmosphere in which the active gas is richer in the latter half of the film formation than in the first half of the film formation.

  Note that “supplying the sputtering gas from the downstream side” does not mean that “only” is supplied from the downstream side to the sputtering target (must be made only from the downstream side), for example, supply from both the upstream and downstream sides. It may be something like that. As a result, it is only necessary to be able to “make the atmosphere in which the active gas is richer (contained more) in the latter half of the film formation than in the first half of the film formation” (that is, with respect to the sputtering target). The supply of sputtering gas from the downstream side is one of the specific means for achieving the above-mentioned “active gas rich (a lot of active gas is contained) in the latter half of film formation”. If it is possible to achieve “active gas rich (contains a lot of active gas)” in the latter half, it is sufficient).

  Thereafter, the transparent substrate 2 mounted on the tray (not shown) is moved in the direction of the arrow S at a predetermined transport speed in the direction of the arrow S, the carry-in chamber LL, the first sputter chamber SP1, the buffer chamber BU, the second sputter chamber SP2, and Transport in the order of the unloading chamber ULL. When the transparent substrate 2 passes near the first sputter target 13 of the first sputter chamber SP1, the main surface of the transparent substrate 2 is made of substantially the same metal silicide material by reactive sputtering. A phase shift film 3 (including the outermost surface layer by oxidation after film formation) made of a single layer film is formed with a predetermined film thickness. The phase shift film 3 is formed in the above-described sputtering gas atmosphere. For this reason, the film formation under the main layer of the phase shift film 3 is performed mainly in an inert gas-rich (a lot of inert gas) sputtering gas atmosphere on the upper stream side of the chamber. The upper film is formed mainly in a sputtering gas atmosphere containing an inert gas and an active gas having a predetermined content on the downstream side. By reactive sputtering in such a sputter gas atmosphere, it is considered that the main layer 3a of the phase shift film 3 proceeds mainly in the latter half of the film formation when the transparent substrate 2 passes downstream. Then, the refractive index of the phase shift film 3 is measured by a spectroscopic ellipsometer under the simulation conditions in which the phase shift film 3 is an inclined film (GradedLayer) in which an oxide film is formed on the outermost surface and the main layer has a refractive index gradient. As a result, the refractive index at a wavelength of 365 nm above the main layer was smaller than the refractive index at a wavelength of 365 nm below the main layer. Patterning is performed by wet etching by making the refractive index at the wavelength 365 nm above the main layer of the phase shift film 3 thus formed, that is, the phase shift film 3 smaller than the refractive index at the wavelength 365 nm below the main layer. The cross-sectional shape of the cross-section to be etched at the edge portion of the phase shift film pattern 3 ′ obtained in this way can be a vertical cross-sectional shape or a nearly vertical cross-sectional shape that can sufficiently exhibit the phase shift effect.

  On the other hand, when the phase shift film is formed by supplying the sputtering gas from the first gas inlet 11 disposed on the upstream side of the first sputtering target 13, the predetermined content is not increased from the upstream side to the downstream side. Since the sputtering gas atmosphere containing the active gas and the active gas is formed, the transparent substrate 2 passes from the first half of the film formation before passing over the first sputter target 13 to the second half of the film formation after passing through the first sputtering target 13. It is thought that film formation proceeds. As a result, when the film is formed under the upstream supply condition of the sputtering gas, an oxide film is formed on the outermost surface of the phase shift film 3, and the simulation condition is that the main layer is a gradient film (film having a refractive index gradient). When the refractive index of the phase shift film 3 is measured by a spectroscopic ellipsometer, the refractive index at a wavelength of 365 nm increases from the lower part of the main layer to the upper part of the main layer, so that the refractive index at the wavelength of 365 nm above the main layer is the wavelength of 365 nm below the main layer. It becomes larger than the refractive index at. The cross-sectional shape of the cross section to be etched at the edge portion of the phase shift film pattern obtained by patterning the phase shift film thus formed by wet etching is tapered.

During the formation of the phase shift film 3, the main valve (not shown) of the exhaust device (not shown) connected to the buffer chamber BU may be closed to stop the exhaust. Further, the transparent substrate 2 may be transported without flowing the sputtering gas into the second sputtering chamber SP2 with the main valve (not shown) closed.
Furthermore, instead of the first sputter target 13 described above, the phase shift film 3 made of a single layer film may be formed using the second sputter target 14. In this case, a predetermined flow rate of sputtering gas is introduced into the first sputtering chamber SP1 from the fourth gas introduction port GA22 downstream of the second sputtering target 14, and a predetermined sputtering power is applied to the second sputtering target 14. Further, instead of the first sputter target 13 or the second sputter target 14 in the first sputter chamber SP1, the phase shift made of a single layer film using the third sputter target 15 or the fourth sputter target 16 in the second sputter chamber SP2. The film 3 may be formed. In this case, a sputter gas having a predetermined flow rate is introduced into the second sputter chamber SP2 from the sixth gas introduction port GA32 (or the eighth gas introduction port GA42) downstream of the third sputter target 15 (or the fourth sputter target 16). Then, a predetermined sputtering power is applied to the third sputter target 15 (or the fourth sputter target 16).

The case where the phase shift film 3 made of a laminated film is formed (deposition multiple times) will be described.
In this case, the transport of the transparent substrate 2 in the direction of the arrow S and the transport in the direction opposite to the arrow S are repeated, and each time the metal substrate is used in the direction of the arrow S, the metal silicide single unit constituting a part of the phase shift film 3. During the first film formation method for forming the phase shift film 3 by sequentially laminating the layer films and the single transfer of the transparent substrate 2 in the direction of the arrow S, the first sputter target 13 to the fourth A second film forming method for forming the phase shift film 3 by sequentially laminating metal silicide single layer films constituting a part of the phase shift film 3 using at least two of the sputter targets 16; There is a third film formation method that combines the first film formation method and the second film formation method. These film forming methods are appropriately selected according to the number of layers of the phase shift film 3.
In these film forming methods, as in the case of forming the phase shift film 3 made of a single layer film, when the transparent substrate 2 is transported in the direction of the arrow S, a sputtering gas having a predetermined flow rate is formed. The phase shift film 3 is formed by supplying from the downstream side of the sputter target used for the above.

In the first film forming method, for example, the following procedure is followed.
The single layer film formed as described above is the first layer of the metal silicide single layer film constituting a part of the phase shift film 3, and then the transparent substrate 2 is placed in the direction opposite to the arrow S. The metal silicide single layer constituting a part of the phase shift film 3 is returned in the order from the carry-out chamber ULL to the carry-in chamber LL, and again, like the above-described film formation of the first metal silicide single-layer film. A second layer of the film is formed.
The same applies when forming the third and subsequent layers of the metal silicide single layer film constituting a part of the phase shift film 3.
By the film forming process using the first film forming method, two or more layers of the same metal silicide-based material having a predetermined film thickness are formed on the main surface of the transparent substrate 2. A phase shift film 3 made of a laminated film having a laminated structure is formed.

In the second film forming method, for example, the following procedure is followed.
First, the transparent substrate 2 is carried into the carry-in chamber LL of the sputtering apparatus 11.
Next, after the inside of the sputtering apparatus 11 is set to a predetermined degree of vacuum, a sputtering gas having a predetermined flow rate is introduced into the first sputtering chamber SP1 from the second gas introduction port GA12 on the downstream side of the first sputtering target 13, and the first sputtering chamber SP1. A sputter gas having the same component as that of the sputter gas introduced into the first sputter chamber SP1 is introduced into the second sputter chamber SP2 from the sixth gas introduction port GA32 on the downstream side of the three sputter target 15 at a predetermined flow rate. A predetermined sputtering power is applied to each of the target 13 and the third sputtering target 15. The application of the sputtering power and the introduction of the sputtering gas are continued until the transparent substrate 2 is transported to the unloading chamber ULL.
Thereafter, the transparent substrate 2 is sequentially transferred from the carry-in chamber LL to the carry-out chamber ULL in the direction of the arrow S at a predetermined transfer speed. When the transparent substrate 2 passes near the first sputter target 13 in the first sputter chamber SP1, one layer of a metal silicide single layer film having a predetermined thickness is formed on the main surface of the transparent substrate 2 by reactive sputtering. The eyes are deposited.
After that, when the transparent substrate 2 passes near the third sputter target 15 in the second sputter chamber SP2, a metal silicide system having a predetermined film thickness is formed on the first metal silicide single layer film by reactive sputtering. A second layer of the single layer film is formed.
When the phase shift film 3 composed of a laminated film having a three-layer structure is formed, in addition to the above-described sputter target, the second sputter target 14 of the first sputter chamber SP1 is further used. A sputtering gas is supplied at a predetermined flow rate from the fourth gas introduction port GA22 on the side, and a predetermined sputtering power is applied to the second sputtering target 14. In this case, the metal silicide single layer film formed when passing near the second sputter target 14 is the second layer of the phase shift film 3 and is formed when passing near the third sputter target 15. The metal silicide single layer film is the third layer of the phase shift film 3.
By the film-forming process using such a second film-forming method, two layers or three or more layers composed of the same metal silicide-based material having a predetermined film thickness are formed on the main surface of the transparent substrate 2. A phase shift film 3 made of a laminated film having a laminated structure is formed.

In the third film formation method, any of the first film formation method and the second film formation method described above may be performed first.
For example, the second film formation method is performed first, a multi-layered metal silicide-based single layer film is laminated during one transport of the transparent substrate 2, and then the first film formation method is performed. By laminating a required number of metal silicide single-layer films, the phase shift film 3 made of a laminated film having a predetermined number of layers can be formed.
By a film forming process using such a third film forming method, a large number of layers of three or more layers are formed on the main surface of the transparent substrate 2 and are made of the same metal silicide material with a predetermined film thickness. A phase shift film 3 made of a laminated film having the above is formed.

  After forming the phase shift film 3 on the main surface of the transparent substrate 2 in this way, the transparent substrate 2 is taken out of the sputtering apparatus 11.

  The phase shift mask blank 1 of Embodiment 1 is manufactured by such a preparation process and a phase shift film formation process.

  According to the phase shift mask blank 1 of Embodiment 1 manufactured in this way, the phase shift film 3 containing metal, silicon, oxygen and / or nitrogen is formed on the transparent substrate 2. The phase shift film 3 has a main layer 3a made of the same material and an outermost surface layer 3b which is a surface oxide layer of the main layer 3a. The refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer 3b side is smaller than the refractive index at a wavelength of 365 nm below the main layer on the transparent substrate 2 side. In the phase shift mask blank 1 having such a configuration, the phase shift film 3 can be patterned into a cross-sectional shape that can sufficiently exhibit the phase shift effect by wet etching. In this phase shift mask blank 1, the cross-sectional shape of the cross section to be etched at the edge portion of the phase shift film pattern 3 ′ obtained by patterning the phase shift film 3 is a cross-sectional shape that can sufficiently exhibit the phase shift effect. Therefore, the resolution can be improved, and an original for manufacturing a phase shift mask having the phase shift film pattern 3 'having good CD characteristics can be obtained.

  In addition, according to the method for manufacturing the phase shift mask blank 1 of Embodiment 1, the main layer 3a containing the metal, silicon, oxygen and / or nitrogen on the transparent substrate 2 and made of the same material, and the main layer 3a. It includes a phase shift film forming step of forming the phase shift film 3 having the outermost surface layer 3b which is the surface oxide layer of the layer 3a by a sputtering method using an in-line type sputtering apparatus. In this phase shift film forming step, the first sputter target 13 containing metal silicide is used, and an inert gas and an active gas that oxidizes and nitrides the phase shift film 3 are supplied to the transparent substrate 2 in the vicinity of the first sputter target 13. The first sputtering target 13 in the transport direction is supplied from the downstream side, and is performed by reactive sputtering using a mixed gas containing an inert gas and an active gas. According to the phase shift film 3 thus formed, the phase shift mask blank 1 that can be patterned into a cross-sectional shape that can sufficiently exhibit the phase shift effect in wet etching can be manufactured. Since the cross-sectional shape of the cross-section to be etched at the edge portion of the phase shift film pattern 3 ′ can be a cross-sectional shape that can sufficiently exhibit the phase shift effect, the phase shift film pattern having improved resolution and good CD characteristics The phase shift mask blank 1 that can be patterned into 3 'can be manufactured.

  In the first embodiment, a mixed gas in which an inert gas and an active gas are mixed in advance is supplied from one gas inlet (for example, the second gas inlet GA12 when the first sputter target 13 is used). Although the phase shift film forming step has been described, the present invention is not limited to this, and the phase shift film forming step is performed while supplying the inert gas and the active gas from the dedicated gas inlets without mixing in advance. Also good.

  In the first embodiment, the case where the inline-type sputtering apparatus 11 having the above-described configuration is used in the film forming process has been described. However, an inline-type sputtering apparatus having another configuration may be used. (For example, any target such as the one without the fourth sputter target 16, the seventh gas introduction port GA41, and the eighth gas introduction port GA42 and the one without the gas introduction port, or the target and the gas introduction port are added. Etc.)

  Furthermore, in the in-line type sputtering apparatus shown in FIG. 2, each gas inlet (second gas inlet GA12, fourth gas inlet GA22, sixth gas inlet GA32, eighth gas inlet) arranged on the downstream side is arranged. If at least one of the GAs 42) is provided, the phase shift film 3 in the first embodiment can be formed. Therefore, each gas inlet (first gas inlet) arranged on the upper side of the river is intentionally provided. All or part of GA11, third gas inlet GA21, fifth gas inlet GA31, seventh gas inlet GA41) may not be provided.

<Embodiment 2>
In the second embodiment, a phase shift mask blank for manufacturing a display device and a manufacturing method thereof, which are different from those in the first embodiment, will be described.
FIG. 3 is a sectional view showing the configuration of the phase shift mask blank 10 according to the second embodiment of the present invention. In addition, the same code | symbol is used about the structure similar to Embodiment 1, and description here is abbreviate | omitted or simplified.

  As shown in FIG. 3, the phase shift mask blank 10 according to the second embodiment includes a phase shift film 3 made of a metal silicide-based material, a metal silicide-based material and a material having etching selectivity on a transparent substrate 2, For example, the etching mask film 4 made of a chromium-based material has a laminated structure.

  The manufacturing method of the phase shift mask blank 10 of Embodiment 2 configured as described above includes a preparation step of preparing a transparent substrate, and a film formation step of forming a phase shift film by sputtering on the main surface of the transparent substrate. (Hereinafter also referred to as a phase shift film forming step) and an etching mask film forming step of forming an etching mask film on the phase shift film by sputtering.

  Since the substrate preparation step and the phase shift film formation step are the same as those in the first embodiment, description thereof will be omitted, and the etching mask film formation step will be described below.

Etching Mask Film Formation Step The etching mask film 4 may be either a light shielding property or a light semi-transmissive property. The chromium-based material constituting the etching mask film 4 is not particularly limited as long as it contains chromium (Cr). Examples of the chromium-based material constituting the etching mask film include chromium, chromium oxide, chromium nitride, chromium carbide, chromium fluoride, and a material containing at least one of them.
This etching mask film forming step uses a sputtering target containing chromium or a chromium 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. , Oxygen gas, nitrogen gas, carbon dioxide gas, nitric oxide-based gas, hydrocarbon-based gas, and fluorine-based gas, and a sputtering gas atmosphere composed of a mixed gas with an active gas containing at least one selected from the group consisting of fluorine-based gases.

  The etching mask film 4 may be either a single layer or a plurality of layers. When the etching mask film 4 is composed of a plurality of layers, for example, in the case of a laminated structure composed of a light shielding layer formed on the phase shift film 3 side and an antireflection layer formed on the light shielding layer, There is a case of a laminated structure including an insulating layer formed so as to be in contact with the shift film 3, a light shielding layer formed on the insulating layer, and an antireflection layer formed on the light shielding layer. The light shielding layer may be composed of one layer or a plurality of layers. Examples of the light shielding layer include a chromium nitride film (CrN), a chromium carbide film (CrC), and a chromium carbon nitride film (CrCN). The antireflection layer may be either a single layer or a plurality of layers. Examples of the antireflection layer include a chromium oxynitride film (CrON). The insulating layer is made of, for example, CrCO or CrCON containing less than 50 atomic% of Cr, and has a thickness of 10 nm to 50 nm. When the etching mask film 4 made of a chromium-based material is wet-etched, metal ions are dissolved from the phase shift film 3 made of a metal silicide-based material. At that time, electrons are generated. When the insulating layer is formed so as to be in contact with the phase shift film 3, it is possible to prevent electrons generated when metal ions are dissolved from the phase shift film 3 from being supplied to the etching mask film 4. For this reason, the in-plane etching rate when the etching mask film 4 is wet-etched can be made uniform.

The etching mask film 4 is formed by the sputtering apparatus 11 (FIG. 2) described in the first embodiment. However, in the second embodiment, the second sputter target 14, the third sputter target 15, and the fourth sputter target 16 use a chromium target or a chromium compound target containing chromium.
In the case where the etching mask film 4 is continuously formed without taking out the transparent substrate 2 outside the sputtering apparatus 11 after the phase shift film 3 is formed, the transparent substrate 2 mounted on a tray (not shown) is used. In the direction opposite to the arrow S, the unloading chamber ULL, the second sputtering chamber SP2, the buffer chamber BU, the first sputtering chamber SP1, and the loading chamber LL are returned in this order. On the other hand, when the etching mask film 4 is formed after the transparent substrate 2 is once taken out of the sputtering apparatus 11 after the phase shift film 3 is formed, the transparent substrate 2 mounted on a tray (not shown) is used. After carrying in to carrying-in chamber LL, as above-mentioned, the inside of sputtering device 11 is made into predetermined vacuum degree.

  In the case of forming the etching mask film 4 having a laminated structure composed of the light shielding layer and the antireflection layer, after that, the sputtering apparatus 11 is kept at a predetermined degree of vacuum from the fourth gas introduction port GA22. A sputtering gas having a flow rate of is introduced, and a predetermined sputtering power is applied to the second sputtering target 14. Further, a predetermined flow rate of sputtering gas is introduced from the sixth gas introduction port GA 32, and a predetermined sputtering power is applied to the third sputtering target 15. Further, a predetermined flow rate of sputtering gas is introduced from the eighth gas introduction port GA 42, and a predetermined sputtering power is applied to the fourth sputtering target 16. The application of the sputtering power and the introduction of the sputtering gas are continued until the transparent substrate 2 is transported to the unloading chamber ULL.

  Thereafter, the transparent substrate 2 mounted on the tray (not shown) is moved in the direction of the arrow S at a predetermined transfer speed in the direction of the arrow S, the first sputtering chamber SP1, the buffer chamber BU, the second sputtering chamber SP2, and Transport in the order of the unloading chamber ULL. When the transparent substrate 2 passes near the second sputter target 14 in the first sputter chamber SP1, a light shielding layer made of a chromium-based material having a predetermined thickness is formed on the phase shift film 3 by reactive sputtering. Be filmed. Further, when the transparent substrate 2 passes near the third sputter target 15 and the fourth sputter target 16 in the second sputter chamber SP2, it is made of a chromium-based material having a predetermined thickness on the light shielding layer by reactive sputtering. A light shielding layer and an antireflection layer are formed.

  After forming an etching mask film 4 having a laminated structure composed of a light shielding layer and an antireflection layer on the phase shift film 3, the transparent substrate 2 is taken out of the sputtering apparatus 11.

  In the case of forming an etching mask film 4 having a laminated structure composed of an insulating layer, a light shielding layer, and an antireflection layer, after the phase shift film 3 is formed on the transparent substrate 2, the inside of the sputtering apparatus 11 is set to a predetermined state. In a vacuum state, a predetermined flow rate of sputtering gas is introduced from the fourth gas introduction port GA22, and a predetermined sputtering power is applied to the second sputtering target.

  Thereafter, the transparent substrate 2 mounted on the tray (not shown) is moved in the direction of the arrow S at a predetermined transfer speed in the direction of the arrow S, the first sputtering chamber SP1, the buffer chamber BU, the second sputtering chamber SP2, and Transport in the order of the unloading chamber ULL. When the transparent substrate 2 passes near the second sputter target 14 in the first sputter chamber SP1, an insulating layer made of a chromium-based material having a predetermined thickness is formed on the phase shift film 3 by reactive sputtering. Be filmed.

  Thereafter, in order to form a light shielding layer and an antireflection layer, the transparent substrate 2 mounted on the tray (not shown) is placed in the direction opposite to the arrow S in the carry-out chamber ULL, the second sputter chamber SP2, the buffer chamber. Returning to the order of BU, the first sputter chamber SP1, and the carry-in chamber LL, the light shielding layer and the antireflection layer are formed as described above.

  After forming an etching mask film 4 having a laminated structure including an insulating layer, a light shielding layer, and an antireflection layer on the phase shift film 3, the transparent substrate 2 is taken out of the sputtering apparatus 11.

  The phase shift mask blank 10 for manufacturing a display device according to the second embodiment manufactured in this way is a phase shift film composed of a transparent substrate 2 and a metal silicide-based material formed on the main surface of the transparent substrate 2. 3 and an etching mask film 4 made of a chromium-based material formed on the phase shift film 3, and the outermost layer 3 b side of the main layer 3 a of the phase shift film 3 as in the first embodiment. The refractive index at a wavelength of 365 nm of the upper part (hereinafter sometimes referred to as the upper part of the main layer) is the refractive index at a wavelength of 365 nm of the lower part (hereinafter also referred to as the lower part of the main layer) on the transparent substrate 2 side of the main layer 3a. Is formed smaller.

  According to the phase shift mask blank 10 of the second embodiment manufactured in this way, the phase shift film is formed in a cross-sectional shape that can sufficiently exhibit the phase shift effect in the wet etching of the phase shift film 3 as in the first embodiment. Patterning is possible, resolution can be improved, and a master for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics can be obtained. Further, by providing the etching mask film 4 made of a chromium-based material, the adhesion with the resist layer formed thereon can be improved, and at the same time, the thickness of the resist layer can be reduced.

In the present embodiment, the light-shielding film (etching mask film 4) is laminated on the phase shift film 3. However, the light-shielding film is formed between the transparent substrate 2 and the phase shift film 3. It may be.
Such a configuration includes a preparation process for preparing the transparent substrate 2, a film forming process for forming the light shielding film 4 on the main surface of the transparent substrate 2 by sputtering, and a light shielding film pattern by patterning the light shielding film 4. Formed by a light shielding film pattern forming step for forming 4 ′ and a phase shift film forming step for forming a phase shift film 3 containing metal, silicon, oxygen and / or nitrogen on the light shielding film pattern 4 ′ can do.

  As described above, the phase shift mask blank of the present invention includes a main layer made of the same material, a main layer composed of a phase shift film containing a metal, silicon, and oxygen and / or nitrogen formed on a transparent substrate. And a refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side is made smaller than a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side. Thereby, even if any phase shift mask blank of the phase shift mask blank of Embodiment 1 mentioned above and the phase shift mask blank of Embodiment 2 is used, the phase shift mask of Embodiment 3 and Embodiment 4 described later is used. By the manufacturing method, the cross-sectional shape of the edge portion of the phase shift film pattern formed on the transparent substrate can be a cross-sectional shape that can sufficiently exhibit the phase shift effect. Therefore, a phase shift mask having a phase shift film pattern with improved resolution and good CD characteristics can be obtained.

<Embodiment 3>
In the third embodiment, a method of manufacturing a phase shift mask for manufacturing a display device (a method of manufacturing a phase shift mask based on the phase shift mask blank of the first embodiment) will be described.
4 (a) to 4 (e) are cross-sectional views showing the steps of the method of manufacturing a phase shift mask according to the third embodiment of the present invention. The same components as those in FIG. Duplicate explanation is omitted.

  The phase shift mask 30 of Embodiment 3 has a configuration in which a phase shift film pattern 3 ′ is formed on the transparent substrate 2.

In the phase shift mask manufacturing method of the third embodiment configured as described above, first, a resist film pattern 5 ′ is formed on the phase shift film 3 of the phase shift mask blank 1 (see FIG. 1) described in the first embodiment. A resist film pattern forming step of forming is performed.
Specifically, in this resist film pattern formation step, first, as shown in FIG. 4A, a phase shift mask blank 1 in which a phase shift film 3 made of a metal silicide material is formed on a transparent substrate 2 is prepared. To do. Thereafter, as shown in FIG. 4B, a resist film 5 is formed on the phase shift film 3. At this time, if the adhesion between the phase shift film 3 and the resist film 5 is not sufficient, a surface treatment (for example, hexamethyldisilazane (HMDS) for improving the adhesion between the phase shift film 3 and the resist film 5 is performed. Processing). Thereafter, as shown in FIG. 4C, after a pattern having a predetermined size is drawn on the resist film 5, the resist film 5 is developed with a predetermined developer to form a resist film pattern 5 '.
Examples of the pattern drawn on the resist film 5 include a line and space pattern and a hole pattern.

Next, as shown in FIG. 4D, a phase shift film pattern forming step is performed in which the phase shift film 3 is wet-etched using the resist film pattern 5 ′ as a mask to form the phase shift film pattern 3 ′.
The etchant for wet-etching the phase shift film 3 is not particularly limited as long as it can selectively etch the phase shift film 3 made of a metal silicide material. For example, etching including at least one fluorine compound selected from hydrofluoric acid, silicohydrofluoric acid, and ammonium hydrogen fluoride, and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid Liquid.

  After the formation of the phase shift film pattern 3 ′, the resist film pattern 5 ′ is peeled off as shown in FIG.

  The phase shift mask 30 of the third embodiment is manufactured by such a resist film pattern forming process and a phase shift film pattern forming process.

  The phase shift film pattern 3 'has a property of changing the phase of the exposure light. Due to this property, a predetermined phase difference is generated between the exposure light transmitted through the phase shift film pattern 3 ′ and the exposure light transmitted only through the transparent substrate 2. When the exposure light is a composite light including light having a wavelength range of 300 nm or more and 500 nm or less, the phase shift film pattern 3 ′ is formed so as to generate a predetermined phase difference with respect to the light having the representative wavelength. For example, when the exposure light is composite light including i-line, h-line, and g-line, the phase shift film pattern 3 ′ has a phase difference of 180 degrees with respect to any of i-line, h-line, and g-line. Form to occur. Further, in order to exert the phase shift effect, for example, the phase difference of the phase shift film pattern 3 ′ in the i-line is set in a range of 180 degrees ± 10 degrees, preferably approximately 180 degrees. Further, for example, the transmittance of the phase shift film pattern 3 ′ for i-line is preferably set in the range of 1% to 20%, particularly preferably 3% to 15%.

  The composition ratio of each element of the phase shift film pattern 3 ′ is such that the outermost surface layer 3 b and the phase shift film pattern 3 ′ formed from the outermost surface of the phase shift film pattern 3 ′ toward the film depth direction and the transparent substrate 2 Is substantially uniform in the main layer 3a excluding the interface region. However, the composition is not uniform in the interface region close to the outermost surface layer 3 b and the transparent substrate 2 formed from the outermost surface of the phase shift film pattern 3 ′ toward the film depth direction.

The cross-sectional shape of the cross section to be etched at the edge portion of the phase shift film pattern 3 ′ is not easily tapered.
Here, the cross-sectional angle (θ) (see FIG. 12 described later) of the cross section to be etched at the edge portion of the phase shift film pattern 3 ′ is 90 degrees or 90 degrees as much as possible in order to sufficiently exhibit the phase shift effect. An angle close to degrees is desirable.
However, even if the cross-sectional angle (θ) is not 90 degrees or an angle close to 90 degrees, the phase shift effect can be sufficiently exhibited. For example, the phase shift close to the resist film pattern 5 ′ is possible even if there is a slight skirt in the cross section to be etched near the transparent substrate 2 in the cross section to be etched at the edge of the phase shift film pattern 3 ′. If many portions of the cross-section to be etched at the edge portion of the film pattern 3 'are 90 degrees or an angle close to 90 degrees, the phase shift effect can be sufficiently exhibited.

  The phase shift mask 30 for manufacturing a display device manufactured as described above is used for projection exposure of equal magnification exposure and sufficiently exhibits a phase shift effect. In particular, as the exposure environment, the numerical aperture (NA) is preferably 0.06 to 0.15, more preferably 0.08 to 0.10, and the coherence factor (σ) is preferably 0.5 to. 1.0.

  According to the method of manufacturing the phase shift mask 30 of the third embodiment, the phase shift mask 30 is manufactured using the phase shift mask blank 1 described in the first embodiment. For this reason, the phase shift mask 30 having the phase shift film pattern 3 ′ that can sufficiently exhibit the phase shift effect can be manufactured. Since the phase shift film pattern 3 ′ can sufficiently exhibit the phase shift effect, the resolution can be improved and the phase shift mask 30 having the phase shift film pattern 3 ′ having good CD characteristics can be manufactured. This phase shift mask 30 can cope with the miniaturization of line and space patterns and contact holes.

  In the third embodiment, the phase shift mask blank 1 having the configuration of the transparent substrate / phase shift film is used as the original plate for manufacturing the phase shift mask 30. However, the present invention is not limited to this. For example, a phase shift mask blank having a transparent substrate / phase shift film / resist film configuration (see FIG. 3B) may be used as a master for manufacturing the phase shift mask 30.

  In the third embodiment, before the resist film pattern forming step, the phase shift film 3 of the phase shift mask blank 1 may be subjected to film cleaning as necessary. A known cleaning method can be used for the film cleaning. However, it is preferable to use a cleaning method other than a cleaning method using a cleaning liquid (for example, sulfuric acid / hydrogen peroxide) containing a sulfur (S) component. In the film cleaning using the cleaning liquid containing the sulfur (S) component, the sulfur (S) component remains on the phase shift film 3. Therefore, when the phase shift film 3 is patterned by the remaining sulfur (S) component to obtain the phase shift film pattern 3 ′, the cross-sectional shape of the cross section to be etched at the edge portion is likely to be a tapered shape. It is.

<Embodiment 4>
In the fourth embodiment, a method for manufacturing a phase shift mask based on the phase shift mask blank of the second embodiment will be described.
5 (a) to 5 (h) are cross-sectional views showing the steps of the method of manufacturing the phase shift mask according to the fourth embodiment of the present invention. The same components as those in FIG. Duplicate explanation is omitted.

First, a resist pattern forming step for forming a resist pattern is performed on the etching mask film 4 of the phase shift mask blank 10 described in the second embodiment.
Specifically, in this resist pattern forming step, first, a resist film 5 is formed on the etching mask film 4 (FIG. 5B). Thereafter, a pattern having a predetermined size is drawn on the resist film 5. Thereafter, the resist film is developed with a predetermined developer to form a resist pattern 5 ′ (FIG. 5C).
Examples of the pattern drawn on the resist film 5 include a line and space pattern and a hole pattern.

Next, an etching mask film pattern forming step is performed in which the etching mask film 4 is wet etched using the resist pattern 5 'as a mask to form the etching mask film pattern 4' (FIG. 5D).
The etchant for wet etching the etching mask film 4 is not particularly limited as long as it can selectively etch the etching mask film 4. Specifically, an etching solution containing ceric ammonium nitrate and perchloric acid can be used.

Next, a phase shift film pattern forming step is performed in which the phase shift film 3 is wet etched using the etching mask film pattern 4 'as a mask to form the phase shift film pattern 3' (FIG. 5E).
The etchant for wet-etching the phase shift film 3 is not particularly limited as long as it can selectively etch the phase shift film 3. For example, etching including at least one fluorine compound selected from hydrofluoric acid, silicohydrofluoric acid, and ammonium hydrogen fluoride, and at least one oxidizing agent selected from hydrogen peroxide, nitric acid, and sulfuric acid Liquid. Specifically, an etching solution obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water can be used.

In the case of manufacturing a type of phase shift mask having a light shielding film pattern on the phase shift film pattern, the etching mask film pattern 4 ′ is narrower than the phase shift film pattern 3 ′ after the phase shift film pattern 3 ′ is formed. To pattern.
Specifically, after removing the resist film pattern 5 ′, a photoresist film 55 is formed so as to cover the etching mask film pattern 4 ′, and the photoresist film 55 is drawn using a laser drawing apparatus, and development and rinsing are performed. Through the process, a resist film pattern 55 ′ is formed on the etching mask film pattern 4 ′ (FIG. 5F).
Thereafter, using the resist film pattern 55 ′ as a mask, the etching mask film 4 ′ is wet-etched with a chromium etching solution containing ceric ammonium nitrate and perchloric acid, and is narrower than the width of the phase shift film pattern 3 ′. An etching mask film pattern 4 ″ is formed (FIG. 5G).
Thereafter, the resist film pattern 55 ′ is peeled off (FIG. 5H).
In this case, the phase shift film pattern 3 ′ has a property of changing the phase of the exposure light, and the etching mask film pattern 4 ″ has a light shielding property.
In the case of manufacturing a type of phase shift mask that does not have a light shielding film pattern on the phase shift film pattern, the etching mask film pattern 4 ′ is peeled after the phase shift film pattern 3 ′ is formed. In this case, the phase shift film pattern 3 'has a property of changing the phase of the exposure light.

  A phase shift mask for manufacturing a display device is manufactured through such a resist pattern forming process, an etching mask film pattern forming process, and a phase shift film pattern forming process.

The phase shift mask of the present embodiment manufactured in this way includes a transparent substrate and a phase shift film pattern made of a metal silicide material formed on the main surface of the transparent substrate. In the case of a type having a light shielding film pattern on the phase shift film pattern, an etching mask film pattern made of a chromium-based material formed on the phase shift film pattern is further provided. A portion where the phase shift film pattern is disposed constitutes a phase shift portion, and a portion where the transparent substrate is exposed constitutes a light transmission portion.
Examples of the phase shift film pattern include a line and space pattern and a hole pattern.

  Hereinafter, based on an Example, this invention is demonstrated more concretely.

(Example 1 and Comparative Example 1)
In Example 1 and Comparative Example 1, a phase shift mask blank having a phase shift film (material: MoSiN) and an etching mask film on a transparent substrate 2 and a phase shift mask manufactured using the phase shift mask blank will be described. .
In the phase shift mask blank 1 of Example 1, the phase shift film 3 is reacted with a reactive gas (from a gas inlet arranged on the downstream side of the sputtering target made of molybdenum silicide (Mo: Si = 1: 4)). (Sputtering gas) was introduced and a film was formed by reactive sputtering (at this time, the opening of the main valve (not shown) of the buffer chamber BU was adjusted, and N ₂ gas was introduced into the second sputtering chamber SP2). In contrast to the manufactured phase shift mask blank of Comparative Example 1, the phase shift film is formed from a gas inlet disposed on the upstream side of the sputtering target made of molybdenum silicide (Mo: Si = 1: 4). A reactive gas (sputtering gas) is introduced and a film is formed by reactive sputtering (at this time, the main bar of the buffer chamber BU). The degree of opening of the lub (not shown) was adjusted, and Ar gas was introduced into the second sputter chamber SP2.

A. Phase shift mask blank and manufacturing method thereof In order to manufacture the phase shift mask blank 1 of Example 1 and Comparative Example 1 having the above-described configuration, first, as a transparent substrate 2, an 8092 size (800 mm × 920 mm) synthetic quartz glass substrate is used. Got ready.

Thereafter, the transparent substrate 2 is carried into an in-line type sputtering apparatus 11 in which a sputtering target made of molybdenum silicide (Mo: Si = 1: 4) shown in FIG. 2 is arranged. As shown in FIG. A phase shift film 3 (thickness 110 nm) made of molybdenum silicide nitride (MoSiN) was formed on the main surface.
The phase shift film 3 is introduced into the first sputtering chamber SP1 from the second gas introduction port GA12 disposed on the downstream side of the first sputtering target 13 made of molybdenum silicide (Mo: Si = 1: 4). ) A mixed gas (Ar: 50 sccm, N ₂ : 100 sccm) containing a gas and nitrogen (N ₂ ) gas is introduced, the sputtering power is set to 10 kW, the transport speed of the transparent substrate 2 is set to 350 mm / min, and the reactive sputtering is performed. A film was formed on the transparent substrate 2. A phase shift film 3 (film thickness: 110 nm) was formed by one film formation.
Note that the phase shift film 3 of Example 1 is formed by adjusting the opening of a main valve (not shown) of an exhaust device (not shown) connected to the buffer chamber BU, and in the second sputter chamber SP2. Was performed under the condition where nitrogen (N ₂ ) gas was introduced from the third gas inlet GA31.

On the other hand, a phase shift film (thickness 110 nm) formed on the transparent substrate 2 is a first gas introduction port GA11 arranged on the upstream side of the first sputter target 13 made of molybdenum silicide (Mo: Si = 1: 4). Then, a mixed gas having the same components as in Example 1 is introduced at the same flow rate (Ar: 50 sccm, N ₂ : 100 sccm) as in Example 1, and Ar gas is introduced into the second sputtering chamber SP2 from the third gas inlet GA31. A phase shift mask blank of Comparative Example 1 was obtained by forming the film once as in Example 1 except that the introduced conditions were adopted.

For the phase shift film 3 of the phase shift mask blank 1 of Example 1 and the phase shift film of the phase shift mask blank of Comparative Example 1, composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS).
As a result, in both Example 1 and Comparative Example 1, a surface oxide layer 3b having a film thickness of about 5 nm in which the oxygen content increases toward the film surface side is formed on the outermost surface layer of the phase shift film. The main layer 3a with almost no change in the content of each element (Mo, Si, N, O) is formed at a depth of about 5 nm to about 105 nm, except near the interface with the synthetic quartz glass substrate (transparent substrate 2). It had been.
In any of Example 1 and Comparative Example 1, in the main layer 3a, the fluctuation range of the content of each element of molybdenum (Mo), silicon (Si), nitrogen (N), and oxygen (O) is small and substantially uniform. It is. The content of each element in the main layer 3a of the phase shift film 3 is 15 atomic% for Mo, 38 atomic% for Si, 45 atomic% for N, and 2 atomic% or less for O. 5 atomic% or less (within ± 2.5 atomic% with respect to the central value (average content) of the content of each element).

Next, the refractive index (n) and extinction coefficient (k) values of the phase shift films of Example 1 and Comparative Example 1 were measured with a spectroscopic ellipsometer. Spectral scanning was performed at 55 ° and 65 °, and the simulation was performed under the following conditions where the mean squared error (MSE) was 5.0 or less.
Main layer: Graded layer
Outermost surface layer: oxide film (Cauchy)

  The MSE of Example 1 was 0.880, and the MSE of Comparative Example 1 was 1.034.

  FIG. 6 is a diagram showing the relationship of the refractive index (n) at a wavelength of 190 nm to 1000 nm with respect to the main layer upper portion and the main layer lower portion of the phase shift film 3 of the phase shift mask blank 10 of Example 1, and FIG. It is a figure which shows the relationship of the refractive index (n) in wavelength 190nm-1000nm with respect to the main layer upper part of the phase shift film of this phase shift mask blank, and the main layer lower part.

As shown in FIG. 6, in the wavelength range, the refractive index (n-Top) of the upper part of the main layer of the phase shift film 3 in the phase shift mask blank 10 of Example 1 is the refractive index (n-Bottom) of the lower part of the main layer. It was found to be smaller than In particular, in i-line (wavelength 365 nm), which is one of wavelengths of an exposure light source (ultra-high pressure mercury lamp: mixed light of i-line, h-line, and g-line) used when manufacturing a display device, The refractive index is smaller than the refractive index of the lower part of the main layer, the refractive index of the upper part of the main layer is 2.60, the refractive index of the lower part of the main layer is 2.74, and the refractive index of the lower part of the main layer relative to the upper part of the main layer. The difference (Δn = main layer upper refractive index−main layer lower refractive index) was −0.14.
On the other hand, as shown in FIG. 7, in the wavelength range, the refractive index (n-Top) of the upper part of the main layer of the phase shift film in the phase shift mask blank of Comparative Example 1 is the refractive index (n-Bottom) of the lower part of the main layer. It was found to be larger than In particular, for i-line (wavelength 365 nm), the refractive index of the upper part of the main layer is 2.69, the refractive index of the lower part of the main layer is 2.65, and the difference in refractive index between the upper part of the main layer and the lower part of the main layer (Δn = Main layer upper refractive index−main layer lower refractive index) was +0.04.

In both Example 1 and Comparative Example 1, the refractive index is measured at a depth of about 5 to 7 nm from the outermost surface of the phase shift film in the upper part of the main layer, and in the lower part of the main layer. The depth from the outermost surface was about 100 to 105 nm.
As is clear from these results, Example 1 in which the phase shift film 3 was formed using the downstream supply condition of the sputtering gas was compared with the case where the phase shift film was formed using the upstream supply condition of the sputtering gas. Compared with Example 1, it turned out that the change tendency of the refractive index of the depth direction of a phase shift film is opposite.

In addition, about the phase shift film | membrane of each phase shift mask blank of Example 1 and Comparative Example 1, the transmittance | permeability was measured with the spectrophotometer U-4100 made from Hitachi High Technology, and a phase difference was measured with MPM-100 made from Lasertec. Was measured. The transmittance values in Example 1 and Comparative Example 1 are all based on Air.
For measuring the transmittance and phase difference of the phase shift film 3, the phase shift film 3 (on the main surface of the transparent substrate 2 of 6025 size (152 mm × 152 mm) set in the same substrate holder (not shown). A substrate with a phase shift film (dummy substrate) on which a film thickness of 110 nm was formed was used.
As a result, the transmittance of Example 1 and Comparative Example 1 at a wavelength of 365 nm was 5.2%, and the phase difference at a wavelength of 365 nm was 180 degrees.
From this result, it was found that desired transmittance and phase difference can be obtained even if the phase shift film is formed under the downstream supply condition of the sputtering gas.

Further, the reflectivity of the phase shift film 3 of the phase shift mask blank 10 of Example 1 and Comparative Example 1 was measured with a spectrophotometer U-4100 manufactured by Hitachi High Technology.
As a result, the reflectance spectrum of Example 1 at wavelengths of 200 nm to 800 nm was substantially the same as the reflectance spectrum of Comparative Example 1. From this result, it was found that a desired reflectance spectrum can be obtained even when the phase shift film is formed under the condition of downstream supply of the sputtering gas.

Next, a light shielding layer and an antireflection layer to be the etching mask film 4 were formed on the phase shift film 3. The light-shielding layer and the antireflection layer have a film surface reflectance with respect to a specific wavelength (for example, g-line) of 15% or less and an optical density OD of 3.0 or more. The gas type, flow rate, and transport speed of the transparent substrate for the fourth gas inlet GA22, the sixth gas inlet GA32, and the eighth gas inlet GA42 near the chromium target of the sputter target 15 and the fourth sputter target 16 are adjusted. Furthermore, the sputtering power applied to each sputtering target was appropriately adjusted. From the fourth gas introduction port GA22, a mixed gas containing argon (Ar) gas and nitrogen (N ₂ ) gas, and from the sixth gas introduction port GA32, a mixed gas containing argon (Ar) gas and methane (CH ₄ ) gas. From the eighth gas introduction port GA42, a mixed gas containing argon (Ar) gas and nitrogen monoxide (NO) gas was introduced. In addition, the application of the sputtering power to each sputtering target and the introduction of the mixed gas from each gas inlet continued until the transparent substrate 2 was transported to the carry-out chamber ULL. In addition, the conveyance speed of the transparent substrate 2 was 400 mm / min.
As a result, on the phase shift film 3, a light shielding layer composed of a laminated film of a chromium nitride film (CrN) having a thickness of 25 nm and a chromium carbide film (CrC) having a thickness of 70 nm, and a chromium oxynitride film (CrON) having a thickness of 20 nm. A laminated film with an antireflection layer made of
Thus, an etching mask film 4 having a laminated structure in which a light shielding layer made of a laminated film of CrN and CrC and an antireflection layer made of CrON were formed in order on the phase shift film 3.

Thereafter, the second sputtering chamber and the carry-out chamber are completely partitioned by the partition plate, and then the carry-out chamber is returned to the atmospheric pressure state, and the transparent substrate on which the phase shift film 3 and the etching mask film 4 are formed is sputtered by the sputtering apparatus 11. It was taken out from.
Thus, the phase shift mask blank 10 in which the phase shift film 3 and the etching mask film 4 were formed on the transparent substrate 2 was obtained.

B. Phase Shift Mask and Manufacturing Method Thereof To manufacture the phase shift masks of Example 1 and Comparative Example 1 using the phase shift mask blanks of Example 1 and Comparative Example 1 manufactured as described above, On the etching mask film 4 of the phase shift mask blank of Example 1 and Comparative Example 1, a photoresist film 5 was applied using a resist coating apparatus.
Thereafter, a photoresist film 5 having a film thickness of 1000 nm was formed through a heating / cooling process.
Thereafter, a photoresist film 5 is drawn using a laser drawing apparatus, and after development and rinsing steps, a line pattern having a line pattern width of 2.0 μm and a space pattern width of 2.0 μm is formed on the etching mask film 4. A resist film pattern 5 ′ having a space pattern was formed.

Thereafter, using the resist film pattern 5 ′ as a mask, the etching mask film 4 was wet etched with a chromium etching solution containing ceric ammonium nitrate and perchloric acid to form an etching mask film pattern 4 ′.
Next, using the etching mask film pattern 4 ′ as a mask, the phase shift film 3 is wet-etched with a molybdenum silicide etchant obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water, and the phase shift film Pattern 3 'was formed.

Thereafter, the resist film pattern 5 ′ was peeled off.
Thereafter, a photoresist film 55 was applied using a resist coating apparatus so as to cover the etching mask film pattern 4 ′.
Thereafter, a 1000 nm-thick photoresist film 55 was formed through a heating / cooling process.
Thereafter, a photoresist film 55 was drawn using a laser drawing apparatus, and a resist film pattern 55 ′ having a line pattern width of 1.0 μm was formed on the etching mask film pattern 4 ′ through development and rinsing processes.
Thereafter, using the resist film pattern 55 ′ as a mask, the etching mask film 4 ′ is wet-etched with a chromium etching solution containing ceric ammonium nitrate and perchloric acid, and is narrower than the width of the phase shift film pattern 3 ′. An etching mask film pattern 4 ″ was formed.
Thereafter, the resist film pattern 55 ′ was peeled off.

  In this way, the phase shift film pattern 3 ′ obtained by patterning the phase shift film 3 on the transparent substrate 2, and the etching mask film pattern narrower than the width of the phase shift film pattern 3 ′ on the phase shift film pattern 3 ′. The phase shift mask 50 of Example 1 in which 4 ″ was formed and the phase shift mask of Comparative Example 1 were obtained.

  The cross section to be etched at the edge portion of each phase shift film pattern 3 ′ of the phase shift mask 50 of Example 1 and the phase shift mask of Comparative Example 1 was observed with a scanning electron microscope before the resist film pattern 5 ′ was peeled off. .

  8 is a cross-sectional photograph of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask of Example 1, and FIG. 9 is a cross-sectional photograph of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask of Comparative Example 1. FIG. 10 is a cross-sectional view for explaining a cross-sectional angle (θ) that is a determination index of the cross-sectional shape of the edge portion.

  In FIG. 10, the cross section of the phase shift film pattern 3 ′ is composed of an upper side, a lower side, and a side side 23 corresponding to the upper surface, the lower surface, and the side surface of the phase shift film pattern 3 ′. In FIG. 10, the auxiliary line 21 indicates the position of the upper side corresponding to the upper surface of the phase shift film pattern 3 ′, and the auxiliary line 22 indicates the position of the lower side corresponding to the lower surface of the phase shift film pattern 3 ′. In this case, the angle θ formed by the straight line connecting the contact point 26 between the upper side and the side side and the position 27 of the side side at a height of 2/3 of the film thickness from the upper surface and the upper side is 85 It is preferable that the angle is in the range of 120 to 120 degrees. In FIG. 10, the auxiliary line 24 indicates a position at a height that is two-thirds lower than the film thickness from the upper surface.

  As shown in FIG. 8, the cross section of the phase shift film pattern 3 ′ of Example 1 is a shape that is completely vertical at a portion in contact with the transparent substrate 2 and substantially vertical at a portion in contact with the etching mask film pattern 4 ′. there were. The angle θ formed by the straight line connecting the contact point between the upper side and the side side and the position of the side side at a height of 2/3 of the film thickness from the upper surface and the upper side was 85 degrees.

Next, CD variation of the phase shift film pattern of the phase shift mask of Example 1 was measured by SIR8000 manufactured by Seiko Instruments Nano Technology. The CD variation was measured at 5 × 5 points in a 740 mm × 860 mm area excluding the peripheral area of the substrate. The CD variation is a deviation width from a target line and space pattern (line pattern width: 2.0 μm, space pattern width: 2.0 μm). In the following examples and comparative examples, the same apparatus was used to measure CD variation.
The CD variation was very good at 0.090 μm.

Moreover, as shown in FIG. 9, the cross section of the phase shift film pattern of Comparative Example 1 was a linear taper shape. The angle θ formed by the upper side and the straight line connecting the contact point between the upper side and the side side and the position of the side side at a height of 2/3 of the film thickness from the upper surface was 135 degrees.
In addition, it was found that the CD variation of the phase shift film pattern of the phase shift mask of Comparative Example 1 was (0.180 μm), which was larger than Example 1.

Next, a light intensity distribution curve at a wavelength of 365 nm in Example 1 and Comparative Example 1 in which a spatial image of light passing through a phase shift mask having a phase shift film pattern having a 2.5 μm square contact hole pattern was simulated ( Comparison of transmission profiles).
The light intensity distribution curve of Example 1 has a sharp peak intensity at the center of the contact hole as compared with Comparative Example 1, the light intensity change is large at the pattern boundary part, and the light intensity in the peripheral area outside the pattern boundary part. The change was small. Therefore, it was found that the phase shift mask of Example 1 showed a stronger light intensity gradient and higher resolution than Comparative Example 1.

(Example 2)
In the second embodiment, a phase shift mask blank in which the etching mask film 4 is not formed on the phase shift film 3 in the first embodiment and a phase shift mask manufactured using the phase shift mask blank will be described.

A. Phase shift mask blank and manufacturing method thereof In the same manner as in Example 1 described above, the phase shift film 3 was formed on the transparent substrate 2 to obtain the phase shift mask blank 1 of Example 2.

B. Phase shift mask and manufacturing method thereof In order to manufacture the phase shift mask of Example 2 using the phase shift mask blank 1 of Example 2 described above, first, the phase shift film 3 of the phase shift mask blank 1 of Example 2 is used. After the surface was treated with HMDS (hexamethyldisilazane), a photoresist film 5 was applied using a resist coating apparatus.
Thereafter, a photoresist film 5 having a film thickness of 1000 nm was formed through a heating / cooling process.
Thereafter, a photoresist film 5 is drawn using a laser drawing apparatus, and after development and rinsing steps, a line pattern having a line pattern width of 2.0 μm and a space pattern width of 2.0 μm is formed on the phase shift film 3. A resist film pattern 5 ′ having a space pattern was formed.

Next, using the resist film pattern 5 'as a mask, the phase shift film 3 is wet-etched with a molybdenum silicide etchant obtained by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water, and the phase shift film pattern 3 'was formed.
Thereafter, the resist film pattern 5 ′ was peeled off.
Thus, the phase shift mask 30 of Example 2 in which the phase shift film pattern 3 ′ obtained by patterning the phase shift film 3 was formed on the transparent substrate 2 was obtained.

The cross section to be etched of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask 30 of Example 2 was observed with a scanning electron microscope.
As a result, the cross section of the phase shift film pattern 3 ′ of Example 2 was slightly linearly tapered as compared with the cross section of the phase shift film pattern 3 ′ of Example 1, but the upper side and the side side The angle θ formed by the straight line connecting the contact point and the position of the side edge at a height that is two-thirds lower than the film thickness from the upper surface and the upper side was as good as 120 degrees.
Similarly to Example 1, the CD variation of the phase shift film pattern 3 ′ of the phase shift mask of Example 2 was 0.105 μm, which was favorable.

(Example 3)
The phase shift mask blank of Example 3 and the phase shift mask manufactured using this phase shift mask blank are the same as those of the exhaust device (not shown) connected to the buffer chamber BU when the phase shift film is formed. A main valve (not shown) is opened, and a mixed gas (Ar: 50 sccm, N ₂ : 100 sccm) containing argon (Ar) gas and nitrogen (N ₂ ) gas from the third gas introduction port GA31 into the second sputtering chamber SP2. The phase shift mask blank and the phase shift mask were produced in the same manner as in Example 1 except that the above was introduced.
In the same manner as in Example 1, the refractive index (n) and extinction coefficient (k) of the phase shift film of Example 3 were measured with a spectroscopic ellipsometer. FIG. 11 shows the result (a graph showing the refractive index for wavelengths 190 nm to 1000 nm in the upper part of the main layer and the lower part of the main layer of the phase shift film).

As shown in FIG. 11, in the wavelength range, the refractive index (n-Top) of the upper part of the main layer of the phase shift film 3 in the phase shift mask blank of Example 3 is the refractive index (n-Bottom) of the lower part of the main layer. It turned out to be smaller. In particular, in i-line (wavelength 365 nm), which is one of wavelengths of an exposure light source (ultra-high pressure mercury lamp: mixed light of i-line, h-line, and g-line) used when manufacturing a display device, The refractive index is smaller than the refractive index of the lower part of the main layer, the refractive index of the upper part of the main layer is 2.60, the refractive index of the lower part of the main layer is 2.72, and the refractive index of the lower part of the main layer relative to the upper part of the main layer. The difference (Δn = main layer upper refractive index−main layer lower refractive index) was −0.12.
The transmittance of Example 3 at a wavelength of 365 nm was 5.2%, and the phase difference at a wavelength of 365 nm was 180 degrees. As in Example 1, the desired transmittance and phase difference were obtained. Further, with respect to the phase shift film of the phase shift mask blank of Example 3, the reflectance of the phase shift film was measured in the same manner as in Example 1. As a result, the reflectance spectrum of Example 3 at wavelengths of 200 nm to 800 nm was substantially the same as the reflectance spectrum of Example 1.

Next, the to-be-etched cross section of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask 30 of Example 3 was observed with a scanning electron microscope before the resist film pattern 5 ′ was peeled, as in Example 1. .
FIG. 12 is a cross-sectional photograph of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask of Example 3.
As shown in FIG. 12, the cross section of the phase shift film pattern 3 ′ of Example 3 has a very small skirt at the portion in contact with the transparent substrate 2, and is almost vertical at the portion in contact with the etching mask film pattern 4 ′. It was a shape. The angle θ formed by the upper side and the straight line connecting the contact point between the upper side and the side side and the position of the side side at a height of 2/3 of the film thickness from the upper surface was 97 degrees.
Further, the CD variation of the phase shift film pattern of the phase shift film of Example 3 was as very good as 0.098 μm.

Example 4
In Example 4, a phase shift mask blank and a phase shift mask were produced using this phase shift mask blank in the same manner as in Example 1 except that the phase shift film 3 in Example 1 was laminated (four-layer structure). .

A. Phase Shift Mask Blank and Manufacturing Method Thereof As a transparent substrate 2, a synthetic quartz glass substrate having the same size as that of Example 1 was prepared.
In Example 4, in the phase shift film forming step, the first gas introduced into the upstream side of the first sputter target 13 made of molybdenum silicide (Mo: Si = 1: 4) in the sputtering apparatus 11 shown in FIG. A gas mixture (Ar: 30 sccm, N ₂ : 30 sccm) containing argon (Ar) gas and nitrogen (N ₂ ) gas was introduced from the opening GA11, the sputtering power was 4 kW, and the transport speed of the transparent substrate 2 was 400 mm / min. As a result, a molybdenum silicide nitride film (MoSiN) having a thickness of 27.5 nm was formed on the transparent substrate 2 by reactive sputtering.
When forming the molybdenum silicide nitride film, the opening degree of the main valve (not shown) of the exhaust device (not shown) connected to the buffer chamber BU is reduced, and the third gas in the second sputter chamber SP2 is reduced. A situation where a mixed gas (Ar: 30 sccm, N ₂ : 30 sccm) containing argon (Ar) gas and nitrogen (N ₂ ) gas has an influence on the atmosphere of the first sputter chamber from the introduction port GA31 (in the second sputter chamber) The introduced mixed gas was supplied to the downstream side of the first sputter target 13).

After the first layer of molybdenum silicide nitride film is formed on the transparent substrate 2, the transparent substrate 2 mounted on the tray (not shown) is transported in the direction opposite to the arrow S and returned to the loading chamber LL. It was.
Thereafter, a second layer, a third layer, and a fourth layer molybdenum silicide nitride film are formed by the same method as that for the first layer molybdenum silicide nitride film, and are formed of four layers of molybdenum silicide nitride films on the transparent substrate 2. A phase shift film having a total film thickness of 110 nm was formed.

The refractive index (n) and extinction coefficient (k) of the phase shift film of Example 4 were measured with a spectroscopic ellipsometer. FIG. 13 shows the result (a graph showing the refractive index for wavelengths 190 nm to 1000 nm in the main layer upper portion and the main layer lower portion of the phase shift film).
As shown in FIG. 13, in the wavelength range, the refractive index (n-top) of the upper part of the main layer of the phase shift film 3 in the phase shift mask blank 10 of Example 4 is the refractive index (n-Bottom) of the lower part of the main layer. It was found to be smaller than In particular, in i-line (wavelength 365 nm), which is one of wavelengths of an exposure light source (ultra-high pressure mercury lamp: mixed light of i-line, h-line, and g-line) used when manufacturing a display device, The refractive index is smaller than the refractive index of the lower part of the main layer, the refractive index of the upper part of the main layer is 2.66, the refractive index of the lower part of the main layer is 2.68, and the refractive index of the lower part of the main layer relative to the upper part of the main layer. The difference (Δn = main layer upper refractive index−main layer lower refractive index) was −0.02.

  The transmittance of Example 4 at a wavelength of 365 nm was 5.2%, and the phase difference at a wavelength of 365 nm was 180 degrees. As in Example 1, the desired transmittance and phase difference were obtained. Further, with respect to the phase shift film of the phase shift mask blank of Example 4, the reflectance of the phase shift film was measured in the same manner as in Example 1. As a result, the reflectance spectrum of Example 4 at wavelengths of 200 nm to 800 nm was substantially the same as the reflectance spectrum of Example 1.

Next, the to-be-etched cross section of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask 50 of Example 4 was observed with a scanning electron microscope before the resist film pattern 5 ′ was peeled, as in Example 1. .
FIG. 14 is a cross-sectional photograph of the edge portion of the phase shift film pattern 3 ′ of the phase shift mask of Example 4.
As shown in FIG. 14, the cross section of the phase shift film pattern 3 ′ in Example 4 was shaped so as to have a skirt at the portion in contact with the transparent substrate 2 and almost vertical at the portion in contact with the etching mask film pattern. . The angle θ formed by the upper side and the straight line connecting the contact point between the upper side and the side side and the position of the side side at a height of 2/3 of the film thickness from the upper surface was 105 degrees.

Thereafter, an etching mask film 4 is formed on the phase shift film 3 by the same method as in Example 1, and a phase shift mask blank in which the phase shift film 3 and the etching mask film 4 are formed on the transparent substrate 2 is formed. Further, a phase shift mask was produced by the same method as in Example 1.
The CD variation of the phase shift film pattern of the phase shift film of Example 4 was as good as 0.096 μm.

  In Example 4, the phase shift film 3 has a laminated structure and the film formation conditions of each layer are the same. However, in the film formation conditions of each layer, the “atmosphere in which the active gas becomes richer ( The film may be formed as an “atmosphere containing a lot of active gas)”.

The examples and comparative examples have been described above.
The difference (Δn) between the refractive index at the wavelength 365 nm at the wavelength 365 nm above the main layer of the phase shift film 3 in Examples 1, 3, 4 and Comparative Example described above, and the phase shift film 3 FIG. 15 shows the relationship with the cross-sectional angle of the phase shift film pattern cross section of the phase shift mask manufactured using the formed phase shift mask blank.
As shown in FIG. 15, when Δn is negative, that is, the refractive index at the wavelength 365 nm above the main layer in the phase shift film 3 is smaller than the refractive index at the wavelength 365 nm below the main layer, the cross-sectional shape of the phase shift film pattern The (cross-sectional angle) is not less than 85 degrees and not more than 120 degrees, and therefore the CD variation of the phase shift mask is also good. Preferably, Δn (n-TOP-n-Bottom) is −0.20 or more and −0.01 or less, more preferably −0.15 or more and −0.02 or less.
In order to obtain good CD characteristics, the phase shift mask may have an inversely tapered shape (cross-sectional angle <90 degrees) as well as a taper shape (cross-sectional angle> 90 degrees). Need to be suppressed. When Δn (that is, the difference between the refractive index at the wavelength of 365 nm at the upper part of the main layer and the refractive index at the wavelength of 365 nm at the lower part of the main layer) is negatively increased, the cross-sectional shape of the phase shift film pattern tends to be an inversely tapered shape If it is too long, good CD characteristics cannot be obtained as in the case of the tapered cross section. Therefore, Δn (n-TOP-n-Bottom) is preferably −0.20 or more, and more preferably −0.15 or more, in order to suppress the reverse taper shape. .

  Moreover, although the above-mentioned Example demonstrated the example of the phase shift mask blank for display apparatus manufacture, and the phase shift mask for display apparatus manufacture, it is not restricted to this. The phase shift mask blank and the phase shift mask of the present invention can also be applied to semiconductor device manufacturing, MEMS (micro electro mechanical system) manufacturing, printed circuit boards, and the like.

  In the above-described embodiment, an example in which the size of the transparent substrate is 8092 size (800 mm × 920 mm) has been described. However, the size is not limited to this and may be other sizes. In the case of a phase shift mask blank for manufacturing a display device, a large transparent substrate is used, and the size of the transparent substrate is 10 inches or longer on one side. The size of the transparent substrate to be used is, for example, 330 mm × 450 mm or more and 2280 mm × 3130 mm or less.

Further, in the case of phase shift mask blanks for semiconductor device manufacturing, MEMS manufacturing, and printed circuit boards, a small transparent substrate is used, and the length of one side of the transparent substrate is 9 inches or less. The size of the transparent substrate used for the phase shift mask blank of the said use is 63.1 mm x 63.1 mm or more and 228.6 mm x 228.6 mm or less, for example. Normally, 6025 size (152 mm x 152 mm) and 5009 size (126.6 mm x 126.6 mm) are used for semiconductor manufacturing and MEMS manufacturing, and 7012 size (177.4 mm x 177.4 mm) for printed circuit boards. Alternatively, a 9012 size (228.6 mm × 228.6 mm) is used.
In the above-described embodiments, the outermost surface layer surface-oxidized to the phase shift film has been described. However, the present invention is not limited to this, and the film density, film composition, crystal structure, surface morphology, The outermost surface layer having different surface roughness may be used.
In the above-described embodiment, the example in which the phase shift film is measured under the simulation condition of the oxide layer and the graded film (GradedLayer) when measuring the refractive index with the spectroscopic ellipso has been described. In the case where a thin etching mask film that can be measured by a spectroscopic ellipso is formed on the phase shift film, it can be performed under simulation conditions in consideration of the etching mask film.

1,10. . . 1. Phase shift mask blank . . 2. Transparent substrate . . Phase shift film 3a. . . Main layer 3b. . . Outermost surface layer 3 ′. . . Phase shift film pattern,
4). . . Etching mask film (light-shielding film)
4 '. . . Etching mask film pattern,
5). . . Resist film 5 '. . . Resist film pattern 11. . . Sputtering apparatus LL. . . Loading chamber SP1. . . First sputter chamber 13. . . First sputter target GA11. . . First gas inlet GA12. . . Second gas inlet 14. . . Second sputter target GA21. . . Third gas inlet GA22. . . Fourth gas inlet BU. . . Buffer chamber SP2. . . Second sputter chamber 15. . . Third sputter target GA31. . . Fifth gas inlet GA32. . . Sixth gas inlet 16. . . Fourth sputter target GA41. . . Seventh gas inlet GA42. . . Eighth gas inlet ULL. . . Unloading chamber 30, 50. . . Phase shift mask

Claims (15)

A phase shift mask blank in which a phase shift film containing a metal, silicon, oxygen and / or nitrogen is formed on a transparent substrate,
The phase shift film has a main layer made of the same material, and an outermost surface layer,
A phase shift mask blank, wherein a refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side is smaller than a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side.   The phase shift mask blank according to claim 1, wherein a difference (Δn) between a refractive index at a wavelength of 365 nm above the main layer and a refractive index at a wavelength of 365 nm below the main layer is -0.01 or less. .   2. The phase shift mask blank according to claim 1, wherein a difference (Δn) between a refractive index at a wavelength of 365 nm above the main layer and a refractive index at a wavelength of 365 nm below the main layer is −0.10 or less. .   The phase shift mask blank according to any one of claims 1 to 3, wherein a refractive index at a wavelength of 365 nm on the main layer is 2.50 or more.   The phase shift mask blank according to any one of claims 1 to 4, wherein an etching mask film is formed on the phase shift film.   6. The phase shift mask blank according to claim 5, wherein the etching mask film has a light shielding film having a light shielding function.   The phase shift mask blank according to claim 5, wherein the etching mask film is a material containing chromium.   The phase shift mask blank according to any one of claims 1 to 7, wherein the phase shift mask blank is an original for producing a phase shift mask by wet etching. A phase shift mask blank manufacturing method comprising forming a phase shift film containing a metal, silicon, oxygen and / or nitrogen on a transparent substrate by a sputtering method using an in-line type sputtering apparatus,
A film forming step of forming the phase shift film having a main layer and an outermost surface layer made of the same material on the transparent substrate, wherein the film forming step includes a metal silicide sputter target including a metal and silicon; The active gas is supplied in the latter half of the phase shift film so that the atmosphere contains more active gas than the first half of the film formation, and the reactivity of the inert gas and the mixed gas containing the active gas is increased. A method for producing a phase shift mask blank, which is performed by sputtering.   An active gas that oxidizes and / or nitrides the phase shift film is supplied from the downstream side to the sputter target in the transport direction of the transparent substrate in the vicinity of the sputter target, thereby forming the first half of the film formation in the second half of the film formation. The method for producing a phase shift mask blank according to claim 9, wherein the atmosphere contains more active gas.   The flow rate of the active gas is adjusted so that the refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side is smaller than the refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side. A method for producing a phase shift mask blank according to claim 9.   Active so that a difference (Δn) between a refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side and a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side is −0.01 or less. The method of manufacturing a phase shift mask blank according to any one of claims 9 to 11, wherein the flow rate of the gas is adjusted.   Active so that a difference (Δn) between a refractive index at a wavelength of 365 nm at the uppermost main layer on the outermost surface layer side and a refractive index at a wavelength of 365 nm at the lower lower layer on the transparent substrate side is −0.10 or less. The method of manufacturing a phase shift mask blank according to any one of claims 9 to 11, wherein the flow rate of the gas is adjusted.   14. The method according to claim 9, further comprising a film forming step of forming an etching mask film on the phase shift film after the film forming step of forming the phase shift film. The manufacturing method of the phase shift mask blank of description.   The phase shift mask blank according to any one of claims 1 to 8 or the phase shift mask blank produced by the manufacturing method according to any one of claims 9 to 14, and patterning the phase shift film by wet etching. A method of manufacturing a phase shift mask for manufacturing a phase shift mask.

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