JP6661262B2 - Phase shift mask blank, method for manufacturing the same, and method for manufacturing phase shift mask - Google Patents

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, for example, using the phase shift mask blank.

  Currently, the VA (Vertical alignment) system and the IPS (In Plane Switching) system are adopted as the system adopted in the liquid crystal display device. With these methods, a liquid crystal display device having high definition, high-speed display performance, and a wide viewing angle has been realized. In a liquid crystal display device to which these methods are applied, the response speed and the viewing angle can be improved by forming the pixel electrodes in a line and space pattern of a transparent conductive film. Recently, from the viewpoints of further improving the response speed and the viewing angle, and improving the light use efficiency of the liquid crystal display device, that is, from the viewpoint of reducing the power consumption and improving the contrast of the liquid crystal display device, the pitch width of the line and space pattern is reduced. Is required. For example, it is desired to reduce the pitch width of the line and space pattern (the sum 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, L ≦ 2 μm, 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 or insulating films on which necessary patterning has been performed. At that time, a photolithography process is often used for patterning the individual films to be laminated. For example, in the case of thin film transistors (“TFTs”) used in these display devices, of a plurality of patterns constituting a TFT, a contact hole formed in a passivation (insulating layer) penetrates the insulating layer. A configuration is adopted in which conduction is made to a connection portion on the lower layer side. 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 formed reliably, correct operation of the display device cannot be guaranteed. In this case, too, together with the improvement in display performance, high integration of device patterns is required, and miniaturization of patterns is required. That is, the diameter of the hole pattern is required to be smaller than 3 μm. For example, a hole pattern having a diameter of 2.5 μm or less, and further, a diameter of 2.0 μm or less is required, and it is considered that a pattern having a diameter of 1.5 μm or less, which is smaller than the hole pattern, will be desired in the near future.

  From such a background, for example, a photomask for manufacturing a display device that can cope with miniaturization of a line and space pattern or a contact hole is desired.

  In realizing miniaturization of line-and-space patterns and contact holes, conventional photomasks have a resolution limit of 3 μm for an exposure machine for manufacturing a display device, so that there is no sufficient process likelihood (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 increases.

  For example, when a photomask having a hole pattern for forming a contact hole is used and this is to be transferred to an object to be transferred, a hole pattern having a diameter exceeding 3 μm is transferred 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, it is conceivable to switch to, for example, an exposure machine having a high NA, but a large investment is required.

  Therefore, in order to improve resolution and cope with miniaturization of line-and-space patterns and contact holes, for example, a phase shift mask is attracting attention as a photomask for manufacturing a display device.

Recently, for example, a phase shift mask including a chromium-based phase shift film has been developed as a photomask for manufacturing a semiconductor device such as an LSI or a super LSI that can be used in manufacturing a display device.
As a conventional chromium-based phase shift mask, a chrome-based phase shift film blank formed by laminating a plurality of single-layer films with different compositions on a transparent substrate was used as a production master. Are known (Patent Documents 1 and 2).

Patent Document 1 discloses a phase shift having a transparent substrate, a transparent region on the transparent substrate, and a region of a translucent layer composed of a multilayer film of a chromium compound formed by physical vapor deposition such as sputtering. A mask is described (see claim 1). This phase shift mask uses a resist film pattern formed on a translucent layer as an etching mask, and is patterned by wet etching with a Cr etchant (see paragraph 0017) or dry etching with Cl ₂ + O ₂ gas (see paragraphs 0017 and 0025). Describes that a vertical processing section can be obtained, and a phase shift mask having good cleaning resistance in physical cleaning such as brush cleaning can be obtained (see paragraph 0029).
Further, it is described that the etching characteristics of a translucent layer composed of a multilayer film can be controlled by the difference in the structure of each layer, and a vertical etching fault can be obtained as compared with a single layer under the same continuous etching condition ( See paragraph 0016). This translucent layer is composed of, for example, a first semi-light-shielding film 2 (65 nm thick) made of CrON and a second semi-light-shielding film 3 (65 nm thick) made of CrOCN (see paragraph 0022, FIG. 1). ). The refractive indices n at a wavelength of 356 nm of the first semi-light-shielding film 2 (CrON) and the second semi-light-shielding film 3 (CrOCN) are 2.3 and 2.4, respectively (see paragraphs 0020 and 0022).

Patent Document 2 discloses a transparent substrate, a translucent region having a translucent region and a transparent region on the transparent substrate, wherein the translucent region is constituted by a translucent film made of a multilayer film of chromium or a chromium compound. A shift mask is described. This phase shift mask uses a resist film pattern formed on a translucent film as an etching mask, and performs wet etching with a Cr etchant (see paragraph 0028), Cl ₂ + O ₂ gas (see paragraph 0028), and CH ₂ Cl ₂ (dichloromethane). It is described that a favorable halftone phase shift mask can be obtained by patterning by dry etching (see paragraphs 0035 and 0043) using + O ₂ gas (see paragraphs 0036 and 0043).
The translucent film of this phase shift mask is formed by laminating a plurality of single-layer films made of different materials (see paragraph 0014, FIGS. 1 to 3). In the case of a two-layer structure, for example, in the case of a two-layer structure, for example, a single-layer film 3 (125 nm in thickness) made of CrOCN formed on the transparent substrate 1 side and a single-layer film 4 of CrN formed thereon ( (Film thickness 9 nm) (see paragraph 0014, FIG. 1). The refractive indices n of the single-layer film 3 and the single-layer film 4 at the i-line (wavelength 365 nm) are 2.4 and 1.9, respectively (see paragraph 0033). When the translucent film has a three-layer structure, for example, a single-layer film 7 (70 nm thick) made of CrOCN formed on the transparent substrate 1 side and a single-layer film 8 made of CrN formed thereon (Thickness: 5 nm) and a single-layer film 9 (thickness: 54.9 nm) made of CrOCN formed thereon (see paragraph 0014, FIG. 3). The refractive indices n of the single film 7, the single film 8, and the single film 9 at the i-line (wavelength 365 nm) are 2.46, 1.94, and 2.46, respectively (see paragraph 0039).

Patent No. 3312702 Patent No. 3262302

  The present inventors have intensively studied a phase shift mask including a chromium-based phase shift film. As a result, when the chromium-based phase shift film is patterned by wet etching using the resist film pattern as a mask, the wet etchant penetrates into the interface between the resist film and the chromium-based phase shift film, and the interface portion is rapidly etched. I understand. For this reason, the cross-sectional shape of the edge portion of the formed chromium-based phase shift film pattern was inclined over the entire edge portion, and had a tapered shape with a skirt toward the transparent substrate.

  When the cross-sectional shape of the edge portion of the chromium-based phase shift film pattern is tapered, the phase shift effect decreases as the thickness of the edge portion of the chrome-based phase shift film pattern decreases. Therefore, the chromium-based phase shift film pattern cannot sufficiently exhibit the phase shift effect. The infiltration of the wet etching solution into the interface between the resist film and the chromium-based phase shift film is caused by poor adhesion between the chromium-based 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, it is not possible to obtain sufficient resolution, and it is very difficult to control the line width (CD). .

  Further, the present inventors have intensively studied a method for verticalizing the cross-sectional shape of the edge portion of the chromium-based phase shift film pattern in order to solve these problems. Until now, for example, by adjusting the content of nitrogen to increase the etching rate or the content of carbon to decrease the etching rate, the film composition of the chromium-based phase shift film is inclined to increase the etching rate in the film thickness direction. (See, for example, Patent Documents 1 and 2). In each of these methods, in order to make the edge portion of the phase shift film pattern a vertical cross section, different materials having different etching characteristics are selected, and a plurality of single-layer films made of the different materials are laminated to form a phase shift film. This is a method for forming a film. However, with these methods, as the size of the transparent substrate increases, it is difficult to control the film thickness distribution and composition in the large plate surface, and particularly to ensure the uniformity of the cross-sectional shape. A phase shift film that does not ensure in-plane uniformity of transmittance, phase difference, and cross-sectional shape can exhibit a desired phase shift effect constantly, and it is very difficult to obtain a phase shift mask having a good in-plane CD range. Was.

  Therefore, 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 capable of sufficiently exhibiting a phase shift effect by wet etching, and manufacturing the same. It is an object of the present invention to provide a method and a method for manufacturing a phase shift mask having a phase shift film pattern capable of sufficiently exhibiting a phase shift effect.

  In order to solve the above-described problems, the present invention has the following configurations.

(Configuration 1) A phase shift mask blank in which a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate,
The phase shift film has a main layer and an outermost surface layer made of the same material, and the refractive index of the upper main layer on the outermost layer side at a wavelength of 365 nm is lower than the wavelength of the lower main layer on the transparent substrate side. A phase shift mask blank having a refractive index smaller than that at 365 nm.

(Structure 2) The structure 1 wherein the refractive index at a wavelength of 365 nm below the main layer is 2.50 or more, and the refractive index at a wavelength of 365 nm above the main layer is 2.45 or less. Phase shift mask blank.

(Structure 3) The structure 1 or 2, wherein a difference between a refractive index of the upper portion of the main layer at a wavelength of 365 nm and a refractive index of the lower portion of the main layer at a wavelength of 365 nm is 0.05 or more and 0.25 or less. Phase shift mask blank.

(Structure 4) The phase shift mask blank according to any one of structures 1 to ³ , wherein the film density of the outermost surface layer is 2.0 g / cm ³ or more.

(Structure 5) The phase shift mask blank according to any one of structures 1 to 4, wherein the phase shift film further contains carbon.

(Structure 6) A method for manufacturing a phase shift mask blank, wherein a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate by a sputtering method using an inline-type sputtering apparatus.
A film forming step of forming the phase shift film having a main layer and an outermost layer made of the same material on the transparent substrate, wherein the film forming step uses a sputter target containing chromium; An active gas and an active gas for oxidizing and nitriding the phase shift film are supplied from the downstream side to the sputter target in the transport direction of the transparent substrate in the vicinity of the sputter target, and the inert gas and the A method for producing a phase shift mask blank, wherein the method is performed by reactive sputtering using a mixed gas containing an active gas.
Note that the phase shift mask blank of Configuration 1 is manufactured by the manufacturing method of Configuration 6.

(Structure 7) The phase according to Structure 6, 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. Manufacturing method of shift mask blank.

(Structure 8) The phase shift mask blank according to Structure 6 or 7, further comprising a vacuum ultraviolet irradiation step of performing a vacuum ultraviolet irradiation process on the outermost surface of the phase shift film after the film forming step. Method.

(Configuration 9) The higher the vacuum ultraviolet irradiation diplomatic the preparation of a phase shift mask blank according to Structure 8, wherein the changing the film density of the outermost surface of the phase shift film to 2.0 g / cm ³ or more Method.

(Structure 10) The method for manufacturing a phase shift mask blank according to any one of structures 6 to 9, wherein the mixed gas further includes an active gas for carbonizing the phase shift film.

(Configuration 11) A phase shift mask blank according to any one of Configurations 1 to 5, or a phase shift mask blank manufactured by the method for manufacturing a phase shift mask blank according to any one of Configurations 6 to 10. Forming a resist film pattern on the phase shift film, wet-etching the phase shift film using the resist film pattern as a mask, and forming a phase shift film pattern on the transparent substrate. Manufacturing method of mask.

  As described above, according to the phase shift mask blank of the present invention, the phase shift film containing chromium, oxygen, and nitrogen is formed on the transparent substrate. This phase shift film has a main layer made of 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 is lower than the wavelength of the lower layer on the transparent substrate side. It is smaller than the refractive index at 365 nm. In the phase shift mask blank having such a configuration, the phase shift film can be patterned by wet etching into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect. Since the phase shift mask blank can have a cross-sectional shape of an edge portion of the phase shift film pattern obtained by patterning the phase shift film, the cross-sectional shape can sufficiently exhibit the phase shift effect. It is possible to improve the resolution and use it as a master for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics.

  Further, according to the method for manufacturing a phase shift mask blank according to the present invention, a phase shift film containing chromium, oxygen, and nitrogen on a transparent substrate and having a main layer and an outermost surface layer made of the same material is provided. And a film forming step of forming a film by a sputtering method using an in-line type sputtering apparatus. In this film forming step, a sputter target containing chromium is used, and an inert gas and an active gas for oxidizing and nitriding the phase shift film are supplied to the sputter target in the transport direction of the transparent substrate near the sputter target. Is supplied from the downstream side, and is performed by reactive sputtering using a mixed gas containing the inert gas and the active gas. According to such a manufacturing method, it is possible to manufacture a phase shift mask blank capable of patterning (etching) a phase shift film into a cross-sectional shape capable of sufficiently exhibiting a phase shift effect. 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 resolution and pattern the phase shift film pattern having good CD characteristics. A phase shift mask blank can be manufactured.

  According to the method for manufacturing a phase shift mask according to the present invention, a phase shift mask is manufactured using the above-described phase shift mask blank. Therefore, it is possible to manufacture a phase shift mask having a phase shift film pattern that can sufficiently exhibit the phase shift effect. Since the phase shift film pattern can sufficiently exhibit the phase shift effect, the resolution can be improved, and a phase shift mask having a phase shift film pattern having good CD characteristics can be manufactured. This phase shift mask can cope with miniaturization of line and space patterns and contact holes.

FIG. 2 is a cross-sectional view illustrating a configuration of a phase shift mask blank according to Embodiment 1 of the present invention. It is a schematic diagram which shows the in-line type sputtering apparatus which can be used for film formation of a phase shift mask blank. (A)-(e) is sectional drawing which shows each process of the manufacturing method of the phase shift mask by Embodiment 3 of this invention. FIG. 13 is a cross-sectional view illustrating a configuration of a phase shift mask blank according to Embodiment 4 of the present invention. (A)-(f) is sectional drawing which shows each process of the manufacturing method of the phase shift mask blank shown in FIG. (A)-(e) is sectional drawing which shows each process of the manufacturing method of the phase shift mask by Embodiment 5 of this invention using the phase shift mask blank shown in FIG.4 and FIG.5 (f). . FIG. 4 is a diagram showing the refractive index at a wavelength of 190 nm to 1000 nm for the upper main layer and the lower main layer of the phase shift film of the phase shift mask blank of Example 1. FIG. 9 is a diagram showing the refractive index at a wavelength of 190 nm to 1000 nm with respect to the upper main layer and the lower main layer of the phase shift film of the phase shift mask blank of Comparative Example 1. FIG. 4 is a diagram showing the refractive index at a wavelength of 365 nm from the outermost surface layer to the lower part of the main layer of the phase shift films of the phase shift mask blanks of Example 1 and Comparative Example 1. 4 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Example 1. 5 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Comparative Example 1. FIG. 4 is a cross-sectional view for explaining a cross-sectional angle in a cross section of an edge portion of a phase shift film pattern of a phase shift mask. FIG. 9 is a diagram showing the refractive index at a wavelength of 190 nm to 1000 nm with respect to the upper main layer and the lower main layer of the phase shift film of the phase shift mask blank of Example 2. FIG. 9 is a diagram showing the refractive index at a wavelength of 190 nm to 1000 nm with respect to the upper main layer and the lower main layer of the phase shift film of the phase shift mask blank of Comparative Example 2. FIG. 9 is a diagram showing the refractive index at a wavelength of 365 nm from the outermost surface layer to the lower part of the main layer of the phase shift films of the phase shift mask blanks of Example 2 and Comparative Example 2. 9 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Example 2. 13 is a cross-sectional photograph showing a cross-sectional shape of an edge portion of a phase shift film pattern of Comparative Example 2.

  Hereinafter, a phase shift mask blank and a method for manufacturing the same according to an embodiment of the present invention, and a method for manufacturing a phase shift mask using the phase shift mask blank will be described in detail.

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

  The phase shift mask blank 1 according to the first embodiment has a configuration in which a phase shift film 3 containing chromium, oxygen, and nitrogen is formed on a transparent substrate 2, as shown in FIG.

The method of manufacturing the phase shift mask blank 1 according to the first embodiment configured as described above includes a preparation step of preparing the transparent substrate 2 and chromium, oxygen, and nitrogen on the main surface of the transparent substrate 2 by sputtering. And a film forming step of forming the contained phase shift film 3 (hereinafter, may be referred to as a phase shift film forming step).
Hereinafter, each step 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 has a property of transmitting the exposure light to be used. For example, synthetic quartz glass, soda lime glass, and alkali-free glass can be used.

2. Phase Shift Film Forming Step Next, as shown in FIG. 1, a phase shift film 3 containing chromium, oxygen, and nitrogen is formed on the main surface of the transparent substrate 2 by a sputtering method using an in-line sputtering device.
In detail, in this phase shift film forming step, a sputter target containing chromium is used, a sputter power is applied, and an inert gas and an active gas for oxidizing and nitriding the phase shift film are made transparent in the vicinity of the sputter target. The phase shift film 3 containing chromium, oxygen, and nitrogen is supplied from the downstream side to the sputter target in the transport direction of the substrate 2 by reactive sputtering using a mixed gas containing an inert gas and an active gas. A film forming process for forming a film is performed.
Here, it does not matter whether the inert gas and the active gas supplied from the downstream side to the sputter target are mixed before the supply. For example, at a predetermined flow rate, after mixing the inert gas and the active gas in advance, the mixed gas may be supplied from one gas inlet, or the predetermined flow rates of the inert gas and the active gas may be respectively supplied. The gas may be supplied from a dedicated gas inlet.

  The phase shift film 3 has a property of changing the phase of the 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 only through the transparent substrate 2. When the exposure light is a composite light including light in a 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 a composite light including i-line, h-line, and g-line, the phase shift film 3 generates a phase difference of 180 degrees with respect to any of the i-line, h-line, and g-line. Formed. Further, in order to exhibit the phase shift effect, for example, the phase difference of the phase shift film 3 at the i-line is set in a range of 180 degrees ± 10 degrees, and is preferably set to approximately 180 degrees. Further, for example, it is preferable that the transmittance of the phase shift film 3 for the i-line is set in a range of 1% or more and 20% or less. In particular, the vacuum ultraviolet (hereinafter sometimes referred to as VUV) irradiation treatment as described in a second embodiment described later affects the quality of the outermost surface of the phase shift film 3, and as a result, the phase shift film formed by wet etching. In order to obtain a cross-sectional shape capable of sufficiently exhibiting the phase effect by the patterning described above, it is preferable to set the film composition so that the transmittance of the phase shift film 3 at the i-line is set in the range of 3% or more and 15% or less.

The phase shift film 3 is made of a chromium-based material containing at least chromium (Cr), oxygen (O), and nitrogen (N). The chromium-based material may further contain carbon (C) as required in addition to the above three elements. When a chromium-based material containing carbon is used, the chemical resistance and cleaning resistance of the phase shift film 3 can be improved.
Specifically, examples of the chromium-based material forming the phase shift film 3 include chromium oxynitride (CrON) and chromium carbonitride (CrOCN). Further, these chromium-based materials may contain hydrogen (H) and fluorine (F) without departing from the effects of the present invention.

The phase shift film 3 can be formed by, for example, the following sputtering target and sputtering gas atmosphere.
As the sputter target used for forming the phase shift film 3, a target containing chromium (Cr) is selected. Specifically, chromium (Cr), chromium nitride, chromium oxide, chromium carbide, chromium oxynitride, chromium oxynitride, chromium oxycarbide, and chromium oxycarbonitride No.
The sputtering gas atmosphere at the time of forming the phase shift film 3 contains an inert gas and an active gas for oxidizing and nitriding the phase shift film. The inert gas is a gas that does not contain a film composition component that constitutes the formed phase shift film 3, and includes a helium (He) gas, a neon (Ne) gas, an argon (Ar) gas, a krypton ( Kr) gas and xenon (Xe) gas, and at least one of these gases is selected. The active gas is a gas containing a film composition component that constitutes the formed phase shift film 3, and includes an oxygen (O ₂ ) gas, a nitrogen (N ₂ ) gas, a nitrogen monoxide (NO) gas, Examples include a nitrogen dioxide (NO ₂ ) gas and a nitrous oxide (N ₂ O) gas, and at least one of these gases is selected. Further, the sputtering gas may include an active gas for carbonizing the phase shift film. Examples of the active gas to be carbonized include carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas, and hydrocarbon-based gas, and at least one of these gases is selected. Examples of the hydrocarbon-based gas include methane gas, butane gas, propane gas, and styrene gas. Further, the sputtering gas may include a fluorine-based gas as an active gas at a supply amount within a range not departing from the effects of the present invention. Examples of the fluorine-based gas include CF ₄ gas, CHF ₃ gas, SF ₆ gas, and a mixture of these gases with an O ₂ gas.
The combination of the above-mentioned material for forming the sputtering target and the type of gas in the sputtering gas atmosphere, and the content ratio of the active gas and the inert gas in the sputtering gas atmosphere depend on the type and composition of the material forming the phase shift film 3. It is determined appropriately according to the situation.

  The thickness of the phase shift film 3 is appropriately adjusted within a range of 80 nm or more and 180 nm or less so that desired optical characteristics (phase difference) can be obtained.

As shown in FIG. 1, the phase shift film 3 includes a main layer 3a made of the same material and an outermost surface layer 3b formed in the depth direction from the outermost surface of the main layer 3a by surface oxidation after film formation. Have. The main layer 3a has such a characteristic that the composition ratio of each element in the film depth direction is substantially uniform (at least it can be said that the composition ratio is substantially uniform in the analysis result by the X-ray photoelectron spectroscopy). This is a main body region of the phase shift film 3 that exhibits a shift effect.
The phase shift film 3 may be either a single layer film or a laminated film. When the phase shift film 3 is composed of a laminated film, the composition and the composition ratio between the interfaces of the respective layers are made to match each other, and for example, by making the etching rate at the time of wet etching constant, 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 step of forming the phase shift film 3 be performed a plurality of times under the same film forming conditions. It is preferable that a plurality of film forming steps be continuously performed in the same in-line type sputtering apparatus. In the case where a plurality of film forming steps are continuously performed, for example, an in-line type sputtering apparatus described later 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.

By the above-described phase shift film forming step, the refractive index at a wavelength of 365 nm of the upper portion of the main layer 3a of the phase shift film 3 on the outermost layer 3b side (hereinafter, also referred to as the upper portion of the main layer) is determined. Of these, the refractive index at a wavelength of 365 nm at the lower portion of the transparent substrate 2 (hereinafter sometimes referred to as the lower portion of the main layer) can be made smaller. The phase shift film 3 having such a configuration can have a cross-sectional shape that can sufficiently exhibit a phase effect by patterning by wet etching.
The refractive index at a wavelength of 365 nm below the main layer is desirably 2.50 or more, and the refractive index at a wavelength of 365 nm above the main layer is desirably 2.45 or less. Further, the difference between the refractive index at a wavelength of 365 nm above the main layer and the refractive index at a wavelength of 365 nm below the main layer is preferably 0.05 or more and 0.25 or less. When the difference in the refractive index at a wavelength of 365 nm is less than 0.05 or more than 0.25, it is difficult to obtain a cross-sectional shape that can exhibit a phase effect by patterning the phase shift film 3 by wet etching. Could be.
By the above-described phase shift film forming step, the refractive index of the upper portion of the main layer is made smaller than the refractive index of the lower portion of the main layer at the measurement wavelength not only at the wavelength of 365 nm but also at a wavelength of 190 nm to 1000 nm, for example. (See FIGS. 7 and 13 described below).

The content of each element constituting the phase shift film 3 is appropriately adjusted so as to have desired optical characteristics (transmittance to exposure light, phase difference).
When the material constituting the phase shift film 3 is CrON, the content of each element in the main layer 3a can be determined by X-ray Photoelectron Spectroscopy (hereinafter sometimes referred to as XPS). According to the analysis results, chromium is adjusted to be in a range of 35 atomic% to 65 atomic%, oxygen is adjusted to be 16 atomic% to 50 atomic%, and nitrogen is adjusted to be in a range of 6 atomic% to 30 atomic%. Preferably, chromium is 41 at.% Or more and 58 at.% Or less, oxygen is 21 at.% Or more and 43 at.% Or less, and nitrogen is 11 at.
When the material constituting the phase shift film 3 is CrCOCN, the content of each element in the main layer 3a is 35 atomic% or more and 60 atomic% or less, and the oxygen content is It is adjusted to be 15 atomic% or more and 45 atomic% or less, nitrogen is adjusted to be 5 atomic% or more and 25 atomic% or less, and carbon is adjusted to be 2 atomic% or more and 15 atomic% or less. Preferably, chromium is 40 to 55 at%, oxygen is 20 to 40 at%, nitrogen is 10 to 20 at%, and carbon is 3 to 10 at%. % Or less.
Further, 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, that the composition ratio of each element in the film depth direction is substantially uniform means that the center of the content of each element in the film depth direction of the phase shift film 3 obtained under the film forming conditions in the above film forming step. This means that the content of each element of the main layer 3a is within a predetermined range of fluctuation with respect to the central content based on the typical value. For example, when the material constituting the phase shift film 3 is CrON, the fluctuation range of chromium is ± 5.0 atomic% with respect to the central content of chromium, and the fluctuation range of oxygen is the central content of oxygen. ± 6.5 at.%, And the fluctuation range of nitrogen is ± 4.5 at.% With respect to the central nitrogen content. Preferably, the variation range of chromium is ± 3.5 at%, the variation range of oxygen is ± 5.5 at%, and the variation range of nitrogen is ± 3.5 at%. When the material constituting the phase shift film 3 is CrCOCN, the fluctuation range of chromium is ± 5.0 atomic% with respect to the central content of chromium, and the fluctuation range of oxygen is the central content of oxygen. ± 6.5 atomic%, the fluctuation range of nitrogen is ± 4.5 atomic% with respect to the central content of nitrogen, and the fluctuation range of carbon is ± 4 with respect to the central content of carbon. 0 atomic%. Preferably, the fluctuation range of chromium is ± 3.5 at%, the fluctuation range of oxygen is ± 5.5 at%, the fluctuation range of nitrogen is ± 3.5 at%, and the fluctuation range of carbon is ± 3.0 at%. It is.
It should be noted that 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 determined during the film forming process for the purpose of giving a stepwise or continuous composition change in the film thickness direction. This can be achieved by forming the phase shift film 3 without performing an operation of changing the method or amount of supplying the sputtering raw material or the sputtering gas.

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

  The sputtering apparatus 11 is of an in-line type, and includes five chambers: a loading chamber LL, a first sputtering chamber SP1, a buffer chamber BU, a second sputtering chamber SP2, and a loading chamber ULL. These five chambers are sequentially arranged in order.

  The transparent substrate 2 mounted on a tray (not shown) is loaded at a predetermined transport speed in the direction of arrow S in the direction of arrow S, the first sputter chamber SP1, the buffer chamber BU, the second sputter chamber SP2, and the unload chamber. They can be transported in the order of ULL. In addition, the transparent substrate 2 mounted on a tray (not shown) is provided with the carry-out chamber ULL, the second sputter chamber SP2, the buffer chamber BU, the first sputter chamber SP1, and the carry-in chamber LL in the direction opposite to the arrow S. Can be returned in order.

The partition between the carry-in chamber LL and the first sputter chamber SP1, and the space between the second sputter chamber SP2 and the carry-out chamber ULL are each partitioned by a partition plate. Further, the loading chamber LL and the unloading chamber ULL can be separated from the outside of the sputtering device 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 exhausts air.

In the first sputter chamber SP1, a first sputter target 13 containing chromium for forming the phase shift film 3 is disposed on the side of the loading chamber LL, and is indicated by an arrow S on the transparent substrate 2 near the first sputter target 13. The first gas inlet GA11 is disposed at a position upstream of the first sputter target 13 in the transport direction, and the second gas inlet GA12 is disposed at a position downstream of the first sputter target 13. I have. In the first sputter chamber SP1, a second sputter target 14 containing chromium for forming the phase shift film 3 is disposed on the buffer chamber BU side, and the arrow S of the transparent substrate 2 near the second sputter target 14 is disposed. The third gas inlet GA21 is disposed at a position upstream of the second sputter target 14 with respect to the transport direction indicated by, and the fourth gas inlet GA22 is disposed at a position downstream of the second sputter target 14. Have been.
Here, the distance between the first sputter target 13 and the downstream second gas inlet GA12 is set wider than the distance between the first sputter target 13 and the upstream first gas inlet GA11. This is because the sputter gas atmosphere is changed by providing a distance between the sputter target and the downstream gas inlet as described later. Similarly, the distance between the second sputter target 14 and the downstream fourth gas inlet GA22 is set wider than the distance between the second sputter target 14 and the upstream third gas inlet GA21. .
In the first sputter chamber SP1, the distance between the sputter target and the downstream gas inlet is set to, for example, 15 cm or more and 50 cm or less, and the distance between the sputter target and the upstream gas inlet is, for example, 1 cm. It is preferable to set it to 5 cm or less.

In the second sputter chamber SP2, a third sputter target 15 containing chromium for forming the phase shift film 3 is disposed on the buffer chamber BU side, and is indicated by an arrow S on the transparent substrate 2 near the third sputter target 15. In the transport direction, a fifth gas inlet GA31 is arranged at a position upstream of the third sputter target 15 and a sixth gas inlet GA32 is arranged at a position downstream of the third sputter target 15. I have.
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 equal to the distance between the third sputter target 15 and the fifth gas inlet GA31 on the upstream side. Is set wider than
In the second sputter chamber SP2, similarly to the first sputter chamber SP1, the distance between the sputter target and the downstream gas inlet is set to, for example, 15 cm or more and 50 cm or less, and the sputter target and the upstream gas The distance from the inlet is preferably set, for example, to 1 cm or more and 5 cm or less.
In FIG. 2, the first sputter target 13, the second sputter target 14, and the third sputter target 15 are indicated by hatching.

Here, a case where the phase shift film 3 formed of a single-layer film is formed (one-time film formation) will be described.
First, the transparent substrate 2 mounted on a tray (not shown) is loaded into the loading 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 sputter gas having a predetermined flow rate is supplied from the second gas inlet GA12 on the downstream side of the first sputter target 13 to an inert gas and an active gas. The mixed gas containing the 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 transferred to the unloading chamber ULL.
Due to the supply of the sputtering gas from the downstream side, on the upstream side of the chamber (at a location far from the second gas inlet GA12), the abundance ratio of the inert gas having a relatively long flight distance increases, and accordingly, It is considered that the atmosphere becomes an inert gas-rich sputtering gas atmosphere in which the content of the active gas is larger than a predetermined content. Further, as the gas moves from the upstream side to the downstream side, the sputtering gas atmosphere has a tendency that the content of the inert gas gradually decreases to a predetermined content (the influence of the difference in the flight distance gradually decreases). At a position near the gas inlet GA12, it is considered that a sputtering gas atmosphere containing a predetermined amount of an inert gas and an active gas is contained.

Thereafter, the transfer chamber LL, the first sputter chamber SP1, the buffer chamber BU, the second sputter chamber SP2, and the transparent substrate 2 mounted on a tray (not shown) are transported at a predetermined transport speed in the direction of arrow S. It is transported 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, a single-layer film composed of the same chromium-based material is formed on the main surface of the transparent substrate 2 by reactive sputtering. The phase shift film 3 having a predetermined thickness is formed. The formation of such a phase shift film 3 is performed in the above-described sputtering gas atmosphere. For this reason, the film formation of the phase shift film 3 below the main layer is performed mainly on the upstream side of the chamber in an inert gas rich sputter gas atmosphere, and the film formation on the main layer upper side is performed on the downstream side. Is performed mainly in a sputtering gas atmosphere containing a predetermined content of an inert gas and an active gas. It is considered that the formation of 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, due to the reactive sputtering in the sputtering gas atmosphere. Therefore, it is considered that the refractive index at a wavelength of 365 nm decreases from the lower portion of the main layer to the upper portion of the main layer, and the refractive index of the upper portion of the main layer at a wavelength of 365 nm can be made smaller than the refractive index of the lower portion of the main layer at a wavelength of 365 nm. According to the phase shift film 3 thus formed, 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 by wet etching can sufficiently exhibit the phase shift effect. , A vertical cross-sectional shape or a cross-sectional shape close to vertical.
Here, the cause of the verticalization of the cross-sectional shape of the etched cross section at the edge of the phase shift film pattern 3 'will be described. The verticalization of the cross-sectional shape is mainly achieved by adhesion between the phase shift film pattern 3 ′ and the resist film (about the degree of penetration of the etching solution), isotropic and anisotropic etching, and etching in the depth direction of the film. Differences in speed, etc. are factors.
When the film is formed under the condition of the downstream supply of the sputtering gas in the present embodiment, the refractive index at a wavelength of 365 nm in the depth direction is small in the upper part of the main layer and large in the lower part of the main layer. For this reason, the etching rate becomes lower at the upper portion of the main layer and becomes higher at the lower portion of the main layer in the section to be etched at the edge portion of the phase shift film pattern 3 '. Thus, it is considered that until the isotropic etching reaches the lower portion of the main layer, the isotropic etching to the upper portion of the main layer does not proceed too much, and the cross-sectional shape of the cross section to be etched becomes vertical.

On the other hand, when a phase shift film is formed by supplying a sputter gas from the first gas inlet GA11 disposed on the upstream side of the first sputter target 13, a predetermined content of the phase shift film extends from the upstream side to the downstream side. Since the sputtering gas atmosphere contains an inert gas and an active gas, the main layer of the phase shift film is formed from the first half of the film formation before the transparent substrate 2 passes above the first sputter target 13 to the second half of the film formation after the transparent substrate 2 passes. It is considered that the film formation proceeds. When the film is formed under the condition of upstream supply of the sputtering gas, 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. Larger than. The cross-sectional shape of the cross-section to be etched at the edge of the phase shift film pattern obtained by patterning the phase shift film thus formed by wet etching is tapered.
Here, the reason why the cross-sectional shape of the etched section at the edge of the phase shift film pattern is tapered is that the refractive index at a wavelength of 365 nm is large in the upper part of the main layer and small in the lower part of the main layer. In the cross section to be etched, the etching rate is higher in the upper portion of the main layer and is lower in the lower portion of the main layer. Thus, it is considered that the isotropic etching proceeds to the upper portion of the main layer before the isotropic etching reaches the lower portion of the main layer, so that the cross-sectional shape of the cross section to be etched 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 in a state where the main valve (not shown) is closed, without flowing the sputtering gas into the second sputtering chamber SP2.
Further, the phase shift film 3 composed of a single layer film may be formed by using the second sputter target 14 instead of the first sputter target 13 described above. In this case, a predetermined flow rate of the sputter gas is introduced into the first sputter chamber SP1 from the fourth gas inlet GA22 downstream of the second sputter target 14, and a predetermined sputter power is applied to the second sputter target 14. In addition, instead of the first sputtering target 13 or the second sputtering target 14 of the first sputtering chamber SP1, the third sputtering target 15 of the second sputtering chamber SP2 is used to form the phase shift film 3 made of a single-layer film. May go. In this case, a predetermined flow rate of the sputter gas is introduced into the second sputter chamber SP2 from the sixth gas inlet GA32 on the downstream side of the third sputter target 15, and a predetermined sputter power is applied to the third sputter target 15.

A case where the phase shift film 3 formed of a laminated film is formed (a plurality of film formations) will be described.
In this case, the transfer of the transparent substrate 2 in the direction of the arrow S and the transfer in the direction opposite to the arrow S are repeated, and each time the transfer in the direction of the arrow S is performed, the chromium-based single layer forming a part of the phase shift film 3 is formed. A first film forming method of forming the phase shift film 3 by sequentially stacking the films, and a first sputtering target 13 and a second sputtering method during one transfer of the transparent substrate 2 in the direction of arrow S. Using at least two of the target 14 and the third sputter target 15, a chromium-based single-layer film constituting a part of the phase shift film 3 is sequentially laminated to form the phase shift film 3. And a third film forming method combining the first film forming method and the second film forming 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 arrow S, a sputtering gas of 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 used as the first layer of the chromium-based single-layer film constituting a part of the phase shift film 3, and then the transparent substrate 2 is moved in the direction opposite to the arrow S, From the carry-out chamber ULL to the carry-in chamber LL, return to the order, and again, in the same manner as the formation of the first-layer chromium-based single-layer film described above, the chromium-based single-layer film 2 A layer is formed.
The same applies to the case where the third and subsequent layers of the chromium-based single-layer film constituting a part of the phase shift film 3 are formed.
By the film forming process using such a first film forming method, two or three or more layers of the same chromium-based material having a predetermined thickness are formed on the main surface of the transparent substrate 2. A phase shift film 3 composed of a laminated film having a structure is formed.

In the second film forming method, for example, the following procedure is followed.
First, the transparent substrate 2 is loaded into the loading chamber LL of the sputtering device 11.
Next, after the inside of the sputtering apparatus 11 is set to a predetermined degree of vacuum, a predetermined flow rate of a sputtering gas is introduced into the first sputtering chamber SP1 from the second gas inlet GA12 on the downstream side of the first sputtering target 13, and A sputter gas having the same composition as the sputter gas introduced into the first sputter chamber SP1 is introduced into the second sputter chamber SP2 from the sixth gas inlet GA32 on the downstream side of the third sputter target 15 at a predetermined flow rate. A predetermined sputtering power is applied to the target 13 and the third sputtering target 15, respectively. The application of the sputtering power and the introduction of the sputtering gas are continued until the transparent substrate 2 is transferred to the unloading chamber ULL.
Thereafter, the transparent substrate 2 is sequentially transported at a predetermined transport speed in the direction of arrow S from the loading chamber LL to the unloading chamber ULL. When the transparent substrate 2 passes near the first sputter target 13 of the first sputter chamber SP1, the first layer of the chromium-based single-layer film having a predetermined thickness is formed on the main surface of the transparent substrate 2 by reactive sputtering. Is formed.
Thereafter, when the transparent substrate 2 passes near the third sputter target 15 in the second sputter chamber SP2, a predetermined thickness of the chromium single layer is formed on the first chromium single layer film by reactive sputtering. A second layer of the film is deposited.
When forming the phase shift film 3 composed of a three-layer laminated film, in addition to the above-mentioned sputter target, the second sputter target 14 of the first sputter chamber SP1 is further used, and the downstream of the second sputter target 14 is used. A sputter gas is supplied at a predetermined flow rate from the fourth gas inlet GA22 on the side, and a predetermined sputter power is applied to the second sputter target. In this case, the chromium-based single-layer film formed when passing near the second sputter target 14 becomes the second layer of the phase shift film 3, and the chromium single-layer film formed when passing near the third sputter target 15 is used. The system single layer film is the third layer of the phase shift film 3.
By the film forming process using the second film forming method, two or three or more layers of the same chromium-based material having a predetermined thickness are formed on the main surface of the transparent substrate 2. A phase shift film 3 composed of a laminated film having a 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-forming method is performed first, a multilayer chromium-based single-layer film is stacked during one transfer of the transparent substrate 2, and then the first film-forming method is performed. By stacking a chromium-based single-layer film with an appropriate number of layers, the phase shift film 3 formed of a stacked film having the number of layers to be stacked can be formed.
By the film forming process using the third film forming method, a large number of three or more layers made of the same chromium-based material having a predetermined thickness are formed on the main surface of the transparent substrate 2. A phase shift film 3 made of a laminated film having the same is formed.

  After the phase shift film 3 is formed 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 the first embodiment is manufactured by such a preparation step and a phase shift film forming step.

  According to the phase shift mask blank 1 of the first embodiment manufactured as described above, the phase shift film 3 containing chromium, oxygen, and nitrogen is formed on the transparent substrate 2. This 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 by wet etching into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect. In the 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 set to a cross sectional shape that can sufficiently exhibit the phase shift effect. Therefore, it is possible to improve the resolution and use it as a master for manufacturing a phase shift mask having a phase shift film pattern 3 'having good CD characteristics.

  Further, according to the method of manufacturing phase shift mask blank 1 of Embodiment 1, main layer 3a containing chromium, oxygen, and nitrogen and made of the same material on transparent substrate 2, and the surface of main layer 3a A phase shift film forming step of forming the phase shift film 3 having the outermost surface layer 3b, which is an oxide layer, by a sputtering method using an in-line type sputtering apparatus is included. In this phase shift film forming step, a first sputter target 13 containing chromium is used, and an inert gas and an active gas for oxidizing and nitriding the phase shift film 3 are applied to the transparent substrate 2 near the first sputter target 13. It is supplied from the downstream side to the first sputter target 13 in the transport direction, and is performed by reactive sputtering using a mixed gas containing an inert gas and an active gas. The phase shift mask blank 1 capable of patterning the phase shift film 3 thus formed into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect by 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 resolution is improved and the phase shift film pattern having good CD characteristics is obtained. 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, when the first sputter target 13 is used, the second gas inlet GA12). 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 an inert gas and an active gas from dedicated gas inlets without mixing in advance. You may.

  Further, in the first embodiment, the case where the in-line type sputtering apparatus 11 having the above-described configuration is used in the film forming process has been described, but an in-line type sputtering apparatus having another configuration may be used. As another in-line type sputtering apparatus, for example, a fourth sputter target (not shown) containing chromium for forming the phase shift film 3 is arranged in the second sputter chamber SP2 on the carry-out chamber ULL side, A seventh gas inlet (not shown) is arranged at a position on the upstream side of the fourth sputter target in the transport direction indicated by the arrow S of the transparent substrate 2 near the fourth sputter target, and A configuration in which an eighth gas inlet (not shown) is arranged at a position downstream of the vehicle. As described above, even when the fourth sputter target (not shown) is arranged, similarly to the arrangement relationship between the other sputter targets and the gas introduction ports arranged on both sides in the transport direction, the fourth sputter target (not shown) is used. The distance between the downstream gas inlet (not shown) and the eighth gas inlet (not shown) is larger than the distance between the fourth sputter target (not shown) and the seventh gas inlet (not shown) upstream. Is also preferably set to be wide.

  Further, in the in-line type sputtering apparatus shown in FIG. 2, the second gas inlet GA12 disposed downstream of the first sputter target 13 and the fourth gas inlet GA22 disposed downstream of the second sputter target 14. If at least one of the sixth gas inlets GA32 disposed downstream of the third sputter target 15 is provided, the phase shift film 3 in the first embodiment can be formed. Therefore, the first gas inlet GA11 arranged upstream of the first sputter target 13, the third gas inlet GA21 arranged upstream of the second sputter target 14, and the third sputter target 15 It is not necessary to provide all or part of the fifth gas inlet GA31 disposed upstream.

Embodiment 2 FIG.
In the second embodiment, a method of manufacturing a phase shift mask blank (transparent substrate / phase shift film) for manufacturing a display device, which is different from the first embodiment, will be described.

  The phase shift mask blank 1 according to the second embodiment has a configuration in which a phase shift film 3 containing chromium, oxygen, and nitrogen and irradiated with VUV is formed on a transparent substrate 2. The phase shift mask blank 1 according to the second embodiment has the same film configuration as the phase shift mask blank 1 according to the first embodiment shown in FIG. 1 in appearance.

The method of manufacturing the phase shift mask blank 1 according to the second embodiment having the above-described configuration is the same as the method of manufacturing the phase shift mask blank 1 described in the first embodiment or the phase shift mask blank described in the first embodiment. The method includes a VUV irradiation step performed on the phase shift film 3 of the phase shift mask blank 1 obtained by the method.
Hereinafter, the VUV irradiation step will be described in detail.

In the VUV irradiation step, the outermost surface of the phase shift film 3 is subjected to VUV irradiation processing.
Here, the VUV irradiation treatment means that an irradiation unit (not shown) of a VUV irradiation apparatus (not shown) is arranged on the outermost surface of the phase shift film 3 as an irradiation target at predetermined intervals along the surface direction. ), While the outermost surface is irradiated with VUV from an irradiation unit (not shown) while scanning the surface.
VUV used in the VUV irradiation treatment refers to ultraviolet light having a short wavelength. It is known that VUV is attenuated mainly by absorption in the atmosphere, but can be attenuated in a vacuum. In the present invention, VUV means ultraviolet light having a wavelength of 10 nm to 200 nm, and it is preferable to use one having a wavelength of 100 nm to 200 nm. Specifically, as the VUV, for example, excimer light having a wavelength of 126 nm (argon), 146 nm (krypton), and 172 nm (xenon) can be used. In the present invention, xenon excimer light having a wavelength of 172 nm is used. Preferably, it is used. Note that heat treatment may be performed with or after the VUV irradiation. However, the reforming effect can be obtained without heating at a high temperature (for example, 200 ° C. or higher).

VUV irradiation conditions in the VUV irradiation treatment are preferably as follows.
The irradiation atmosphere is not particularly limited, and may be an inert gas such as nitrogen or a vacuum, but the reforming effect can be obtained even in the air. However, when performing the VUV irradiation process in the atmosphere, it is preferable to reduce the distance between the irradiation unit (not shown) of the VUV irradiation apparatus and the outermost surface of the phase shift film 3 in consideration of the VUV attenuation rate. .
It is important that the VUV irradiation energy be energy sufficient for the modification processing of the phase shift film 3. For example, the uppermost surface of the phase shift film 3 is set to 20 J / cm ² or more, preferably 30 J / cm ² or more, more preferably 40 J / cm ² or more. In addition, from the viewpoint of irradiation efficiency, it is preferably 60 J / cm ² or less.
VUV irradiation, for example, using radiation unit having a source light illumination ^{30W / cm 2 ~50W / cm 2} ( not shown) (not shown), to the outermost surface of the phase shift film 3, more than 20 minutes Irradiation (in the case where the same portion on the outermost surface is irradiated a plurality of times by scanning, irradiation for the total time) can be performed. Specifically, when the light source (not shown) has an illuminance of 40 W / cm ² , the length of the irradiation area is 200 mm, the scanning speed is 10 mm / sec, and the attenuation rate is 70%, the VUV is about 20 minutes. Irradiation can provide an irradiation energy of 45 J / cm ² to the outermost surface. Here, the attenuation rate refers to a ratio of a remaining amount after attenuation to an irradiation amount from an irradiation unit (not shown).
It is preferable that the VUV irradiation be performed not from the transparent substrate 2 side but from the outermost surface side of the phase shift film 3 from the viewpoint of the attenuation rate and the irradiation efficiency of the transparent substrate 2.

In the phase shift mask blank 1 according to the second embodiment thus manufactured, the phase shift film 3 is modified by the VUV irradiation step, and the film density of the outermost surface of the phase shift film 3 is 2.0 g / cm. ³ or more. It is preferable that the film density on the outermost surface is 2.0 g / cm ³ or more, from the viewpoint of improving chemical resistance and washing resistance, and it is more preferable that the film density be 2.2 g / cm ³ or more.

The phase shift film 3 has the following characteristics by the VUV irradiation step.
(1) In the VUV irradiation step, the maximum value of the refractive index at, for example, a wavelength of 365 nm of the outermost surface layer 3b of the phase shift film 3 is reduced as compared with the case where the VUV irradiation step is not performed. In order to reduce the tendency of the phase shift film 3 to decrease in the depth direction by reducing the tendency of the main layer 3a to decrease in the depth direction at a wavelength of, for example, 365 nm, the main layer 3a is modified. (For example, see Example 1 (FIG. 9) and Example 2 (FIG. 15) described later). Here, it is considered that the reason why the refractive index of the outermost surface layer 3b decreases is that the apparent refractive index decreases due to an increase in surface roughness due to the VUV irradiation step. By such a modification treatment, the phase shift film 3 can have a low refractive index in the upper portion of the main layer and a high refractive index in the lower portion of the main layer. In the section to be etched at the edge portion of the phase shift film pattern 3 ′ to be etched, the etching rate becomes lower at the upper portion of the main layer and the etching rate becomes higher at the lower portion of the main layer, so that the tapered cross section of the section to be etched is suppressed, The cross-sectional shape can sufficiently exhibit the phase shift effect. It should be noted that reducing the maximum value and the decreasing tendency of the refractive index of the outermost surface layer 3b and decreasing the increasing tendency of the refractive index of the main layer 3a by the VUV irradiation step is because the refractive index in the phase shift film 3 is reduced. Since the change is small, it is considered that the isotropic etching in the patterning easily proceeds, which contributes to the suppression of the tapered cross-sectional shape of the cross section to be etched.
On the other hand, using a sputter target containing chromium, an inert gas and an active gas for oxidizing and nitriding the phase shift film are applied to the sputter target in the transport direction of the transparent substrate in the vicinity of the sputter target. In a conventional phase shift mask blank having a phase shift film supplied and formed from the upstream side, the VUV irradiation step is performed on the outermost surface layer of the phase shift film as compared with the case where the VUV irradiation step is not performed. For example, the maximum value of the refractive index at a wavelength of 365 nm is reduced, the increasing tendency of the refractive index in the depth direction is increased, and the decreasing tendency of the main layer, for example, the refractive index at a wavelength of 365 nm in the depth direction is reduced, or A modification is made such that the refractive index difference in the depth direction of the phase shift film 3 is increased by making the phase shift film 3 substantially flat (for example, Comparative Example 1 described later). 9), see Comparative Example 2 (FIG. 15)).
(2) Since the VUV treatment step has an effect of improving the wettability of the outermost surface, the adhesion between the phase shift film 3 and the resist film can be improved. Therefore, tapering is suppressed by slowing the penetration of the etchant into the interface between the resist film and the phase shift film 3 by the VUV treatment.
(3) In the VUV irradiation step, a modification can be performed in which the film density on the outermost surface is changed to be high. The reason why the film density on the outermost surface of the phase shift film 3 is increased is that VUV irradiation treatment supplies other atoms to the holes around the chromium atoms present on the outermost surface and fills the holes. Conceivable. Other atoms include, for example, oxygen atoms. In this case, it is considered that by filling the vacancies with oxygen atoms, the density of “CrO” on the outermost surface increases, and as a result, the film density on the outermost surface increases.
Specifically, the film density on the outermost surface can be changed to 2.0 g / cm ³ or more by the VUV irradiation step. It is considered that an increase in the film density on the outermost surface may contribute to improving the adhesion to the resist film 5 used for patterning the phase shift film 3.
Further, assuming that the increase in the film density on the outermost surface is caused by the increase in the density of “CrO” as described above, the assumption is that the cross-sectional shape of the etched section at the edge portion of the phase shift film pattern 3 ′ is This is considered to be supported by the effect that the cross-sectional shape can sufficiently exhibit the shift effect. That is, when oxygen (O) is supplied to the outermost surface, the content of nitrogen (N) for increasing the etching rate is relatively reduced, so that isotropic etching (wet etching) at the time of patterning the phase shift film 3 is performed. In (2), the etching rate of the section to be etched (near the outermost surface) near the resist film 5 in the section to be etched at the edge portion is reduced. For this reason, the etched cross-section near the resist film 5 can withstand up to the lower portion of the edge after the main surface of the transparent substrate 2 is exposed by etching. This is because it is considered that the occurrence of the so-called biting phenomenon due to the etching liquid is reduced in the portion.
The film density on the outermost surface can be measured by, for example, X-ray reflectivity analysis (XRR). The value of the film density on the outermost surface in the example and the comparative example is such that the numerical index Fit R indicating the validity of the fitting at the time of performing the simulation by dividing the phase shift film 3 into a plurality of parts in the film thickness direction is 0.025. It was obtained under the following simulation conditions.
(4) The VUV irradiation step does not change the composition ratio of each element in the film depth direction of the main layer 3a. Therefore, the composition ratio of each element in the film depth direction of the main layer 3a remains substantially uniform as in the case where the VUV irradiation step is not performed. That is, even if the VUV irradiation step is performed, the composition ratio of each element in the film depth direction of the main layer 3a of the phase shift film 3 before the VUV irradiation step does not significantly change. Desired optical characteristics (transmittance, phase difference) can be maintained.
(5) As described above, the VUV irradiation step hardly changes the transmittance of the phase shift film 3 during film formation, and the edge portion of the phase shift film pattern 3 ′ obtained by patterning the phase shift film 3. Is completely different from the case where the VUV irradiation step is not performed, and can be a cross-sectional shape that can sufficiently exhibit the phase shift effect. In the VUV irradiation step, the reflectance of the phase shift film 3 during film formation hardly changes. This indicates that the CD variation of the phase shift film pattern 3 'can be controlled to a very narrow range, and it is considered that the VUV irradiation step is also effective in this regard.

  The phase shift mask blank 1 according to the second embodiment is manufactured by a preparation step, a phase shift film forming step, and a VUV irradiation step.

According to the phase shift mask blank 1 of Embodiment 2 manufactured in this way, the phase shift film 3 containing chromium, oxygen, and nitrogen and subjected to the VUV irradiation treatment is formed on the transparent substrate 2. ing. As in the first embodiment, this 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, and the film density on the outermost surface is 2.0 g / cm ³ or more. It is. For this reason, in the phase shift mask blank 1, the phase shift film 3 can be patterned by wet etching into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect. In the 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 obtained by patterning the phase shift film 3 is set to a cross sectional shape that can sufficiently exhibit the phase shift effect. Therefore, it is possible to improve the resolution and use it as a master for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics.

Further, according to the method of manufacturing phase shift mask blank 1 of Embodiment 2, main layer 3a containing chromium, oxygen, and nitrogen on transparent substrate 2 and made of the same material, and main layer 3a A phase shift film forming step of forming the phase shift film 3 having the outermost surface layer 3b, which is a surface oxide layer, by a sputtering method using an in-line type sputtering device, and irradiating VUV to the outermost surface of the formed phase shift film 3 A VUV irradiation step for performing a process is included. In the phase shift film forming step, as in the first embodiment, the first sputter target 13 is used, and an inert gas and an active gas are supplied to the first sputter target 13 from the downstream side, and the It is performed by reactive sputtering using an active gas and a mixed gas containing the active gas. Thereby, the refractive index at the wavelength of 365 nm above the main layer on the outermost surface layer 3b side of the formed phase shift film 3 can be made smaller than the refractive index at the wavelength of 365 nm below the main layer on the transparent substrate 2 side. . Further, the VUV irradiation step reduces the maximum value of the refractive index of the outermost surface layer 3b of the phase shift film 3 at, for example, a wavelength of 365 nm, reduces the tendency of the refractive index to decrease, and reduces the refractive index of the main layer 3a at a wavelength of, for example, 365 nm. The tendency to increase the refractive index is reduced, and the film density on the outermost surface is changed to 2.0 g / cm ³ or more. Therefore, the phase shift mask blank 1 capable of patterning the phase shift film 3 into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect by 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 can be a cross-sectional shape that can sufficiently exhibit the phase shift effect, the resolution can be improved, and the phase shift film pattern having good CD characteristics can be obtained. The phase shift mask blank 1 that can be patterned can be manufactured.

  Note that a VUV irradiation step as a subsequent step may be performed on the phase shift film 3 of the transparent substrate 2 formed by the phase shift film forming step in Embodiment 2 immediately after the film formation, or After storing in a predetermined case for a predetermined period after film formation, a VUV irradiation step may be performed. The storage may be, for example, for a period of about one month, but is not limited to this. If the VUV processing step is performed before storage, for example, even after storage for about one month, the phase formed by wet etching using the resist pattern as a mask regardless of the presence or absence of cleaning (excluding sulfuric acid cleaning) The cross-sectional shape of the shift film pattern is better than the cross-sectional shape that has not been subjected to VUV processing. When performing the VUV irradiation step after storage, it is not necessary to perform a predetermined film cleaning. Although the exposed portion such as the outermost surface of the phase shift film 3 may be slightly contaminated during storage, even if it is contaminated, it does not affect the modification effect by the VUV irradiation step. Preferably, it is desirable to perform the VUV irradiation step immediately before forming the resist film. Also, in the process of manufacturing a photomask blank, if the surface of the phase shift film 3 is washed with sulfuric acid and then a resist pattern is formed on the phase shift film 3, the cross-sectional shape of the phase shift film pattern becomes tapered. By performing VUV irradiation after the shift film 3 is washed with sulfuric acid and before forming the resist film, the cross-sectional shape of the phase shift film pattern is unlikely to be tapered, and may be made vertical. That is, if the surface of the phase shift film 3 is washed with sulfuric acid, the adhesion between the resist film and the film surface of the phase shift film 3 is significantly reduced, so that the cross-sectional shape after the wet etching process using the resist pattern as a mask has a very large taper. Because of the shape, the resolution of the phase shift film cannot be used effectively. By performing the VUV irradiation step even after washing the phase shift film 3 with sulfuric acid, the sectional shape of the phase shift film pattern can be significantly improved. Further, by strengthening the rinsing of the phase shift film 3 after sulfuric acid cleaning and reducing the sulfur component as much as possible, the VUV irradiation step may be performed to make the cross-sectional shape of the phase shift film pattern vertical.

  The phase shift mask blank 1 of Embodiment 2 in which the VUV irradiation step has been performed may be used as a production master in a method for producing a phase shift mask immediately after the VUV irradiation step. Further, even if the phase shift mask blank 1 is stored in a predetermined case for a predetermined period, the modifying effect of the VUV irradiation process on the phase shift film 3 is maintained. For this reason, after storage, it can be used as a production master in a method for producing a phase shift mask. As described above, since the phase shift mask blank 1 can be stored, a certain amount of the phase shift mask blank 1 is stocked, and can be used at the time of shipping, manufacturing of the phase shift mask, etc., and the handling property can be improved. it can. The storage may be for a period of about two weeks, for example, but is not limited to this.

Embodiment 3 FIG.
In the third embodiment, a method of manufacturing a phase shift mask (transparent substrate / phase shift film pattern) for manufacturing a display device will be described.
3 (a) to 3 (e) are cross-sectional views showing steps of a method for manufacturing a phase shift mask according to Embodiment 3 of the present invention. And duplicate explanations are omitted.

  The phase shift mask 30 according to the third embodiment has a configuration in which a phase shift film pattern 3 ′ is formed on a transparent substrate 2.

In the manufacturing method of the phase shift mask of the third embodiment configured as described above, first, the phase shift mask blank 1 (see FIG. 1) described in the first or second embodiment, or the first or second embodiment. A resist film pattern forming step of forming a resist film pattern 5 ′ on the phase shift film 3 of the phase shift mask blank 1 obtained by the method for manufacturing a phase shift mask blank described in (1) is performed.
Specifically, in this resist film pattern forming step, first, as shown in FIG. 3A, a phase shift mask blank 1 in which a phase shift film 3 made of a chromium-based material is formed on a transparent substrate 2 is prepared. . Thereafter, a resist film 5 is formed on the phase shift film 3 as shown in FIG. Thereafter, as shown in FIG. 3C, a pattern of a predetermined size is drawn on the resist film 5, and then the resist film 5 is developed with a predetermined developing solution 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. 3D, a phase shift film pattern forming step of forming the phase shift film pattern 3 'by wet-etching the phase shift film 3 using the resist film pattern 5' as a mask is performed.
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 chromium-based material. Specifically, an etching solution containing ceric ammonium nitrate and perchloric acid can be used.

  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 according to the third embodiment is manufactured by such a resist film pattern forming step and a phase shift film pattern forming step.

  The phase shift film pattern 3 ′ has a property of changing the phase of the exposure light, similarly to the phase shift film 3 of the phase shift mask blank 1. 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 in 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 of the representative wavelength. For example, when the exposure light is a 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 the i-line, h-line, and g-line. It is formed to produce. In order to exhibit the phase shift effect, for example, the phase difference of the phase shift film pattern 3 ′ at the i-line is set in a range of 180 ± 10 degrees, and is preferably set to approximately 180 degrees. Further, for example, the transmittance of the phase shift film pattern 3 ′ at the i-line is preferably set in the range of 1% to 20%, particularly preferably in the range of 3% to 15%.

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

Since the outermost surface of the phase shift film 3 has been subjected to the above-described VUV irradiation process, the cross-sectional shape of the etched cross section at the edge portion of the phase shift film pattern 3 ′ is unlikely to be 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. It is desirable that the angle be close to degrees.
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, of the cross-sections to be etched at the edges of the phase shift film pattern 3 ′, even if there is a slight skirt in the cross-section to be etched at the edge near the transparent substrate 2, the phase shift is close to the resist film pattern 5 ′. 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 exerted.

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

  According to the method of manufacturing phase shift mask 30 of the third embodiment, phase shift mask blank 1 described in the first or second embodiment or the method of manufacturing phase shift mask blank described in the first or second embodiment is used. The phase shift mask 30 is manufactured using the obtained phase shift mask blank 1. Therefore, it is possible to manufacture the phase shift mask 30 having the phase shift film pattern 3 ′ that can sufficiently exhibit the phase shift effect. Since the phase shift film pattern 3 'can sufficiently exhibit the phase shift effect, it is possible to improve the resolution and manufacture the phase shift mask 30 having the phase shift film pattern 3' having good CD characteristics. This phase shift mask 30 can cope with 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, but the present invention is not limited to this. For example, a phase shift mask blank having a configuration of a transparent substrate / phase shift film / resist film (see FIG. 3B) may be used as a production master of 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 needed. 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 containing sulfur (S) component (for example, sulfuric acid / hydrogen peroxide). In film cleaning using a cleaning liquid containing a 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 residual 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 tends to be tapered. It is.

Embodiment 4 FIG.
In the fourth embodiment, a phase shift mask blank (transparent substrate / light-shielding film pattern / phase shift film) for manufacturing a display device and a method for manufacturing the same will be described.
FIG. 4 is a cross-sectional view showing a configuration of a phase shift mask blank according to Embodiment 4 of the present invention. FIGS. FIG. 4 is a cross-sectional view showing a process, in which the same components as those in FIGS.

  The phase shift mask blank 10 according to the fourth embodiment includes a transparent substrate 2, a light-shielding film pattern 4 ′ formed on the main surface of the transparent substrate 2, a light-shielding film pattern 4 ′ and a light-shielding film pattern 4 ′ on the main surface of the transparent substrate 2. And the phase shift film 3 formed on the substrate.

The manufacturing method of the phase shift mask blank 10 according to the fourth embodiment configured as described above includes a preparing step of preparing the transparent substrate 2 and forming the light shielding film 4 on the main surface of the transparent substrate 2 by sputtering. A light-shielding film forming step (hereinafter, sometimes referred to as a light-shielding film forming step), a light-shielding film pattern forming step of patterning the light-shielding film 4 to form a light-shielding film pattern 4 ′, A phase shift film forming step of forming the phase shift film 3 containing oxygen and nitrogen is included.
Hereinafter, each step will be described in detail.

1. Preparation Step First, the transparent substrate 2 is prepared.
This preparation step is performed in the same manner as the preparation step in the first embodiment.

2. Light-Shielding Film Forming Step Next, as shown in FIG. 5A, a light-shielding film 4 is formed on the main surface of the transparent substrate 2 by sputtering.
Specifically, in this light-shielding film forming step, a film-forming step of forming a light-shielding film 4 made of a predetermined material by applying a sputtering power in a sputtering gas atmosphere is performed.

  The material and thickness of the light-shielding film 4 are adjusted so that the optical density of the light-shielding film 4 with respect to the exposure light in total with the phase shift film 3 is 2.8 or more, preferably 3.0 or more. .

The material forming the light shielding film 4 is not particularly limited, but is preferably a material used for a mask blank. Examples of the material used for the mask blank include a material containing chromium, a material containing tantalum, and a material containing metal and silicon (Si) (metal silicide material). The material containing chromium is not particularly limited as long as it contains chromium (Cr). For example, chromium (Cr), chromium oxide, chromium nitride, chromium carbide, and chromium fluoride Is mentioned. The material containing tantalum is not particularly limited as long as it contains tantalum (Ta), and examples thereof include tantalum (Ta), a tantalum oxide, and a tantalum nitride. Examples of the metal silicide material include a metal silicide nitride, a metal silicide oxide, a metal silicide oxynitride, a metal silicide carbonitride, a metal silicide oxycarbide, and a metal silicide oxycarbonitride. Can be Examples of the metal include transition metals such as molybdenum (Mo), tantalum (Ta), tungsten (W), and titanium (Ti). The composition of the metal and silicon is adjusted from the viewpoint of the optical characteristics of the light shielding film 4. The ratio of metal to silicon is appropriately selected depending on the type of metal and the optical characteristics required for the light-shielding film, and preferably, metal: silicon = 1: 1 to 1: 9.
The material forming the light-shielding film 4 may include other elements such as oxygen (O), nitrogen (N), and carbon (C) as necessary.

  The light-shielding film 4 may be either a single layer or a plurality of layers. When the light-shielding film 4 is composed of a plurality of layers, for example, there is a case where the light-shielding layer is formed on the phase shift film 3 side and an antireflection layer is formed on the light-shielding layer. The light-shielding layer may be either a single 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 carbonitride film (CrCN). The anti-reflection layer is provided on the surface of the light-shielding film for the purpose of reducing the reflectance of exposure light, and the anti-reflection layer may be formed of one layer or a plurality of layers. Is also good. An example of the antireflection layer is a chromium oxynitride film (CrON).

  For forming the light shielding film 4, a sputtering device such as a cluster type sputtering device or an in-line type sputtering device is used.

The light-shielding film 4 can be formed by, for example, the following sputtering target and sputtering gas atmosphere.
As a sputter target used for forming the light-shielding film 4 made of a material containing chromium, one containing chromium (Cr) or a chromium compound is selected. Specifically, chromium (Cr), chromium nitride, chromium oxide, chromium carbide, chromium oxynitride, chromium oxynitride, chromium oxycarbide, and chromium oxycarbonitride No.
The sputtering gas atmosphere at the time of forming the light-shielding film 4 made of a material containing chromium includes nitrogen (N ₂ ) gas, nitric oxide (NO) gas, nitrogen dioxide (NO ₂ ) gas, and nitrous oxide (N ₂ O). An active gas containing at least one selected from the group consisting of gas, carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas, oxygen (O ₂ ) gas, hydrocarbon-based gas and fluorine-based gas, and helium (He) A) a gas mixture of an inert gas containing at least one selected from the group consisting of gas, neon (Ne) gas, argon (Ar) gas, krypton (Kr) gas, and xenon (Xe) gas. Examples of the hydrocarbon-based gas include methane gas, butane gas, propane gas, and styrene gas.
The combination of the material for forming the sputtering target and the type of gas in the sputtering gas atmosphere and the mixing ratio of the active gas and the inert gas in the sputtering gas atmosphere depend on the type and composition of the chromium-based material forming the light shielding film 4. Is appropriately determined according to the conditions.

As the sputter target used for forming the light-shielding film 4 made of a material containing tantalum, a sputter target containing tantalum (Ta) or a tantalum compound is selected. Specific examples include tantalum (Ta), a tantalum oxide, and a tantalum nitride.
At the time of forming the light-shielding film 4 made of a material containing tantalum, the sputtering gas atmosphere is nitrogen (N ₂ ) gas, nitric oxide (NO) gas, nitrogen dioxide (NO ₂ ) gas, nitrous oxide (N ₂ O). An active gas containing at least one selected from the group consisting of gas, carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas and oxygen (O ₂ ) gas, helium (He) gas, neon (Ne) gas, It is composed of a mixed gas with an inert gas containing at least one selected from the group consisting of argon (Ar) gas, krypton (Kr) gas and xenon (Xe) gas.
The combination of the above-described material for forming the sputtering target and the type of gas in the sputtering gas atmosphere, and the mixing ratio of the active gas and the inert gas in the sputtering gas atmosphere depend on the type of the tantalum-containing material constituting the light-shielding film 4. It is appropriately determined according to the composition.

As a sputter target used for forming the light shielding film 4 made of a metal silicide material, a sputter target containing metal and silicon (Si) is selected. Specifically, metal silicide, metal silicide nitride, metal silicide oxide, metal silicide carbide, metal silicide oxynitride, metal silicide carbonitride, metal silicide oxycarbide, and metal silicide Oxycarbonitrides.
At the time of forming the light-shielding film 4 made of a metal silicide material, the sputtering gas atmosphere is nitrogen (N ₂ ) gas, nitric oxide (NO) gas, nitrogen dioxide (NO ₂ ) gas, nitrous oxide (N ₂ O) gas. , An active gas containing at least one selected from the group consisting of carbon monoxide (CO) gas, carbon dioxide (CO ₂ ) gas and oxygen (O ₂ ) gas, helium (He) gas, neon (Ne) gas, argon It is made of a mixed gas with an inert gas containing at least one selected from the group consisting of (Ar) gas, krypton (Kr) gas and xenon (Xe) gas.
The combination of the above-described material for forming the sputtering target and the type of gas in the sputtering gas atmosphere and the mixing ratio of the active gas and the inert gas in the sputtering gas atmosphere depend on the type and composition of the metal silicide material constituting the light shielding film 4. Is appropriately determined according to the conditions.

The light-shielding film forming step can be performed, for example, using the sputtering apparatus 11 shown in FIG.
Here, a case where the light-shielding film 4 made of a material containing chromium is formed will be described as an example.
First, for example, when forming a light-shielding film 4 having a laminated structure composed of a light-shielding layer and an anti-reflection layer, a first sputtering including chromium for forming the light-shielding layer of the light-shielding film 4 is performed in the first sputtering chamber SP1. The target 13 is arranged, and the third sputter target 15 containing chromium for forming the antireflection layer of the light shielding film 4 is arranged in the second sputter chamber SP2.

  Thereafter, in order to form the light-shielding film 4, the transparent substrate 2 mounted on a tray (not shown) is carried into the carry-in chamber LL.

  Thereafter, with the inside of the sputtering apparatus 11 kept at a predetermined degree of vacuum, a predetermined flow rate of a sputter gas is introduced from the second gas inlet GA12, and a predetermined sputter power is applied to the first sputter target 13. Further, a predetermined flow rate of a sputtering gas is introduced from the sixth gas inlet GA32, and a predetermined sputtering power is applied to 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 transferred to the unloading chamber ULL.

  Thereafter, the transfer chamber LL, the first sputtering chamber SP1, the buffer chamber BU, the second sputtering chamber SP2, and the transparent substrate 2 mounted on a tray (not shown) are transported in the direction of arrow S at a predetermined transport speed. It is transported 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, a light-shielding layer composed of a chromium-based material having a predetermined thickness is formed on the main surface of the transparent substrate 2 by reactive sputtering. Is formed. When the transparent substrate 2 passes near the third sputter target 15 in the second sputter chamber SP2, an antireflection layer made of a chromium-based material having a predetermined thickness is formed on the light shielding layer by reactive sputtering. A film is formed.

  After forming a light-shielding film 4 having a laminated structure composed of a light-shielding layer and an anti-reflection layer on the main surface of the transparent substrate 2, the transparent substrate 2 is taken out of the sputtering apparatus 11.

3. Next, a light-shielding film pattern forming step of forming a light-shielding film pattern 4 ′ on the main surface of the transparent substrate 2 is performed.
More specifically, in this light-shielding film pattern forming step, first, a resist film 5 is formed on the light-shielding film 4 as shown in FIG. Thereafter, as shown in FIG. 5C, a pattern having a predetermined size is drawn on the resist film 5, and then the resist film 5 is developed with a predetermined developing solution 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. 5D, a light-shielding film pattern forming step of forming the light-shielding film pattern 4 'by wet-etching the light-shielding film 4 using the resist film pattern 5' as a mask is performed.
When the light-shielding film 4 is made of a chromium-based material, the etchant for wet-etching the light-shielding film 4 is not particularly limited as long as it can selectively etch the light-shielding film 4. Specifically, an etching solution containing ceric ammonium nitrate and perchloric acid can be used.
When the light-shielding film 4 is made of a metal silicide material, the etchant for wet-etching the light-shielding film 4 is not particularly limited as long as it can selectively etch the light-shielding film 4. For example, etching including at least one fluorine compound selected from hydrofluoric acid, hydrosilicofluoric 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 is used.
When the light-shielding film 4 is made of a tantalum-based material, the etchant for wet-etching the light-shielding film 4 is not particularly limited as long as it can selectively etch the light-shielding film 4. Specifically, an etching solution containing sodium hydroxide and hydrogen peroxide can be used.
After the formation of the light-shielding film pattern 4 ', the resist film pattern 5' is peeled off as shown in FIG.

4. Phase Shift Film Forming Step Next, as shown in FIG. 5F, a phase shift film forming step of forming the phase shift film 3 on the light shielding film pattern 4 ′ on the transparent substrate 2 is performed.
This phase shift film forming step is performed similarly to the phase shift film forming step in the first embodiment.

  The phase shift mask blank 10 of the fourth embodiment is manufactured by such a preparation step, a light shielding film forming step, a light shielding film pattern forming step, and a phase shift film forming step.

  According to the phase shift mask blank 10 of the fourth embodiment manufactured in this manner, the light-shielding film pattern 4 ′ is provided on the main surface of the transparent substrate 2 and directly on the main surface of the transparent substrate 2. A phase shift film 3 containing chromium, oxygen, and nitrogen is formed. This 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 10 having such a configuration, the phase shift film 3 can be patterned by wet etching into a cross-sectional shape that can sufficiently exhibit the phase shift effect. In the phase shift mask blank 10, the cross-sectional shape of the etched cross-section at the edge portion of the phase shift film pattern 3 'obtained by patterning the phase shift film 3 is set to a cross-sectional shape that can sufficiently exhibit the phase shift effect. Therefore, it is possible to improve the resolution and use it as a master for manufacturing a phase shift mask having a phase shift film pattern having good CD characteristics.

  Further, according to the method for manufacturing the phase shift mask blank 10 of the fourth embodiment, chromium is directly formed on the main surface of the transparent substrate 2 via the light-shielding film pattern 4 ′ and directly on the main surface of the transparent substrate 2. A phase shift film 3 having a main layer 3a containing oxygen and nitrogen and made of the same material and having an outermost surface layer 3b which is a surface oxide layer of the main layer 3a is formed by a sputtering method using an in-line type sputtering apparatus. It includes a film forming step of forming a film. In this phase shift film forming step, a first sputter target 13 containing chromium is used, and an inert gas and an active gas for oxidizing and nitriding the phase shift film 3 are applied to the transparent substrate 2 near the first sputter target 13. It is supplied from the downstream side to the first sputter target 13 in the transport direction, and is performed by reactive sputtering using a mixed gas containing an inert gas and an active gas. The phase shift mask blank 10 capable of patterning the phase shift film 3 thus formed into a cross-sectional shape capable of sufficiently exhibiting the phase shift effect by 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 can be a cross-sectional shape that can sufficiently exhibit the phase shift effect, the resolution can be improved, and the phase shift film pattern having good CD characteristics can be obtained. The phase shift mask blank 10 that can be patterned can be manufactured.

  In the fourth embodiment, as in the second embodiment, the VUV irradiation step may be performed on the outermost surface of the phase shift film 3 after the phase shift film formation step.

Embodiment 5 FIG.
In the fifth embodiment, a method of manufacturing a phase shift mask (transparent substrate / light-shielding film pattern / phase shift film pattern) for manufacturing a display device will be described.
6 (a) to 6 (e) are cross-sectional views showing steps of a method for manufacturing a phase shift mask according to Embodiment 5 of the present invention using the phase shift mask blank shown in FIG. 5 are denoted by the same reference numerals, and redundant description will be omitted.

  The phase shift mask 31 manufactured by the method for manufacturing a phase shift mask blank according to the fifth embodiment has a light-shielding film pattern 4 ′ on the main surface of the transparent substrate 2 and directly on the main surface of the transparent substrate 2. , A phase shift film pattern 3 ′ containing chromium, oxygen, and nitrogen is formed.

In the manufacturing method of the phase shift mask of the fifth embodiment configured as described above, first, the phase shift mask blank 10 (see FIG. 4) described in the fourth embodiment or the phase shift mask described in the fourth embodiment. A resist film pattern forming step of forming a resist film pattern 5 'is performed on the phase shift film 3 of the phase shift mask blank 10 (see FIG. 5 (f)) obtained by the shift mask blank manufacturing method.
More specifically, in this resist film pattern forming step, first, as shown in FIG. 6A, a light-shielding film pattern 4 ′ is formed on the main surface of the transparent substrate 2, and First, a phase shift mask blank 10 on which a phase shift film 3 containing chromium, oxygen, and nitrogen is formed is prepared. Thereafter, a resist film 5 is formed on the phase shift film 3 as shown in FIG. Thereafter, as shown in FIG. 6C, a pattern of a predetermined size is drawn on the resist film 5, and then the resist film 5 is developed with a predetermined developing solution 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. 6D, a phase shift film pattern forming step of forming the phase shift film pattern 3 'by wet etching the phase shift film 3 using the resist film pattern 5' as a mask is performed.
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 chromium-based material. Specifically, an etching solution containing ceric ammonium nitrate and perchloric acid can be used.
The obtained phase shift film pattern 3 ′ has a property of changing the phase of the exposure light, similarly to the phase shift film pattern 3 ′ in the second embodiment, and the cross-sectional shape of the cross section of the edge portion to be etched is Since the phase shift film according to the present invention is formed and the outermost surface of the phase shift film 3 has been subjected to the above-described VUV irradiation treatment, it is unlikely to have a tapered shape.

  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 31 of the fifth embodiment is manufactured by such a resist film pattern forming step and a phase shift film pattern forming step.
The phase shift mask 31 for manufacturing a display device manufactured as described above is used for projection exposure of the same-size exposure, and exhibits a sufficient phase shift effect. In particular, as the exposure environment, the numerical aperture (NA) is preferably from 0.06 to 0.15, more preferably from 0.08 to 0.10, and the coherence factor (σ) is preferably from 0.5 to 1.0.

  According to the method for manufacturing the phase shift mask 31 of the fifth embodiment, the phase obtained by the method for manufacturing the phase shift mask blank 10 described in the fourth embodiment or the phase shift mask blank described in the fourth embodiment. The phase shift mask 31 is manufactured using the shift mask blank 10. Therefore, it is possible to manufacture the phase shift mask 31 having the phase shift film pattern 3 ′ that can sufficiently exhibit the phase shift effect. Since the phase shift film pattern 3 'can sufficiently exhibit the phase shift effect, it is possible to improve the resolution and manufacture the phase shift mask 31 having the phase shift film pattern 3' having good CD characteristics. This phase shift mask 31 can cope with miniaturization of line and space patterns and contact holes.

  In the fifth embodiment, the phase shift mask blank 10 having the configuration of the transparent substrate / light-shielding film pattern / phase shift film (see FIG. 6A) has been described as an original plate for manufacturing the phase shift mask 31. However, the present invention is not limited to this. For example, a phase shift mask blank having a configuration of a transparent substrate / light-shielding film pattern / phase shift film / resist film (see FIG. 6B) may be used as a master for manufacturing the phase shift mask 31.

  Further, in the fifth embodiment, similarly to the third embodiment, before the above-described resist film pattern forming step, the phase shift film 3 of the phase shift mask blank 10 may be subjected to film cleaning as necessary. Good. 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 containing sulfur (S) component (for example, sulfuric acid / hydrogen peroxide).

  Hereinafter, the present invention will be described more specifically based on examples.

Example 1 and Comparative Example 1.
In Example 1 and Comparative Example 1, a phase shift mask blank having a phase shift film (material: CrOCN) and a phase shift mask manufactured using the phase shift mask blank will be described.
In the phase shift mask blank 1 according to the first embodiment, a reactive gas (sputter gas) is introduced into the phase shift film 3 from a gas inlet disposed downstream of a sputter target made of chromium. (At this time, the main valve (not shown) of the buffer chamber BU is closed, and no gas is supplied to the second sputter chamber SP2). A mask blank is formed by introducing a reactive gas (sputter gas) through a gas inlet port located on the upstream side of a chromium sputter target and depositing the phase shift film by reactive sputtering. The main valve (not shown) of the chamber BU is opened, and the same gas is supplied to the second sputtering chamber SP2. In that they are manufactured, it is different.

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

Thereafter, the transparent substrate 2 is carried into an in-line type sputtering apparatus 11 in which a sputter target made of chromium shown in FIG. 2 is arranged, and as shown in FIG. A phase shift film 3 (125 nm in film thickness) made of CrOCN) was formed.
The phase shift film 3 is provided in the first sputter chamber SP1 from a second gas inlet GA12 disposed downstream of the first sputter target 13 made of chromium, from an argon (Ar) gas and a carbon dioxide (CO ₂ ) gas. And a mixed gas containing nitrogen (N ₂ ) gas (Ar: 46 sccm, N ₂ : 46 sccm, CO ₂ : 45 sccm), the sputter power is set to 3.5 kw, and the transport speed of the transparent substrate 2 is set to 200 mm / min. A film was formed on the transparent substrate 2 by reactive sputtering. The phase shift film 3 (film thickness 125 nm) was formed by one film formation.
The phase shift film 3 of the first embodiment is formed by closing the main valve (not shown) of the exhaust device (not shown) connected to the buffer chamber BU to stop the exhaust, and to stop the second sputter chamber SP2. This was performed under the condition that the sputtering gas was not introduced into the inside. When the phase shift film 3 is formed under these conditions, it is expected that the cross-sectional shape of the edge portion of the phase shift film pattern may be tapered. The film forming conditions were adjusted so that the rate was less than 5%.

On the other hand, a phase shift film (125 nm thick) formed on the transparent substrate 2 was mixed with the same components as in Example 1 through the first gas inlet GA11 disposed on the upstream side of the first sputter target 13 made of chromium. One time as in Example 1 except that the gas was introduced at a flow rate different from that of Example 1 (Ar: 46 sccm, N ₂ : 46 sccm, CO ₂ : 35 sccm) and the sputtering power was set to 3.40 kw. The phase shift mask blank of Comparative Example 1 was obtained by film formation.

With respect to 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 having a thickness of about 8 nm in which the oxygen content increases toward the film surface was formed on the outermost surface layer of the phase shift film. Except for the vicinity of the interface with the synthetic quartz glass substrate (transparent substrate 2), a main layer having almost no change in the content of each element (Cr, C, O, N) is formed at a depth of about 8 nm to about 115 nm. Was.
In each of Example 1 and Comparative Example 1, in the main layer, the fluctuation range of the content of each element of chromium (Cr), oxygen (O), nitrogen (N), and carbon (C) was small and substantially uniform. is there. The content of each element in the main layer of the phase shift film was 50 ± 3 atomic% for Cr, 29 ± 5 atomic% for O, 15 ± 3 atomic% for N, and 6 ± 3 atomic% for C.

Next, the values of the refractive index (n) and the extinction coefficient (k) 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 under which the Mean Squared Error (MSE) was 5.0 or less.
Main layer: Laminated film (Graded layer)
Outermost layer: oxide film (Cauchy)

  The MSE of Example 1 was 4.852, and the MSE of Comparative Example 1 was 4.867.

  FIG. 7 is a view showing the relationship between the refractive index (n) at a wavelength of 190 nm to 1000 nm with respect to the main layer upper part and the main layer lower part of the phase shift film 3 of the phase shift mask blank 1 of Example 1, and FIG. FIG. 9 is a diagram showing the relationship between the refractive index (n) at a wavelength of 190 nm to 1000 nm for the main layer upper part and the main layer lower part of the phase shift film of the phase shift mask blank of FIG. FIG. 7 is a diagram showing the refractive index at a wavelength of 365 nm from the outermost surface layer of the blank phase shift film to the lower portion of the main layer.

As shown in FIG. 7, it was found that the refractive index of the upper part of the main layer of the phase shift film 3 in the phase shift mask blank 1 of Example 1 was smaller than the refractive index of the lower part of the main layer in the wavelength range. In particular, at the i-line (wavelength 365 nm), which is one of the wavelengths of an exposure light source (ultra-high pressure mercury lamp: a mixture of i-line, h-line, and g-line) used when manufacturing a display device, the upper part of the main layer is exposed. The refractive index was lower than the refractive index of the lower part of the main layer, the refractive index of the upper part of the main layer was 2.41, and the refractive index of the lower part of the main layer was 2.60.
On the other hand, as shown in FIG. 8, in the wavelength range, it was found that the refractive index of the upper part of the main layer of the phase shift film in the phase shift mask blank of Comparative Example 1 was larger than the refractive index of the lower part of the main layer. In particular, at the i-line (wavelength 365 nm), the refractive index at the upper part of the main layer was 2.60, and the refractive index at the lower part of the main layer was 2.53.
In each of Example 1 and Comparative Example 1, the measurement position of the refractive index was set at a depth of about 10 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 surface was about 100 nm.
As shown in FIG. 9, in Example 1, the refractive index at the wavelength of 365 nm in the outermost surface layer 3b of the phase shift film 3 tends to decrease, and the refractive index at the wavelength of 365 nm in the main layer 3a tends to increase. On the other hand, in Comparative Example 1, the refractive index at a wavelength of 365 nm increased in the outermost layer of the phase shift film, and the refractive index at a wavelength of 365 nm decreased in the main layer. As is apparent from these results, in Example 1 in which the phase shift film 3 was formed by using the downstream supply condition of the sputtering gas, the phase shift film was formed by using the upstream supply condition of the sputtering gas. It was found that the change tendency of the refractive index in the depth direction of the phase shift film was exactly opposite to that in Example 1.

With respect to the phase shift films of the phase shift mask blanks of Example 1 and Comparative Example 1, the film density on the outermost surface was measured by X-ray reflectivity analysis (XRR).
The film density on the outermost surface was measured by measuring the film density of the phase shift film 3 from the surface layer in a depth direction of 2.2 nm. As a result, the film density of the outermost surface of the phase shift film 3 of Example 1 was 2.36 g / cm ³ , and the film density of the outermost surface of the phase shift film of Comparative Example 1 was 2.28 g / cm ³ . . The numerical index Fit R indicating the validity of the fitting when calculating the film density was 0.012 in Example 1 and 0.013 in Comparative Example 1.

The transmittance of each of the phase shift films of the phase shift mask blanks of Example 1 and Comparative Example 1 was measured by a spectrophotometer U-4100 manufactured by Hitachi High-Technologies Corporation, and the phase difference was measured by MPM-100 manufactured by Lasertec. Was measured. The transmittance values in Example 1 and Comparative Example 1 are Air-based values.
To measure the transmittance and the 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) is used. A substrate (dummy substrate) with a phase shift film having a thickness of 125 nm was used.
As a result, the transmittance at a wavelength of 365 nm of Example 1 was 3.0%, and the transmittance at a wavelength of 365 nm of Comparative Example 1 was 5.3%.
The phase difference at a wavelength of 365 nm in Example 1 was 185 degrees, and the phase difference at a wavelength of 365 nm in Comparative Example 1 was 181.8 degrees. From this result, it was found that a desired phase difference could be obtained even if the phase shift film was formed under the condition of downstream supply of the sputtering gas.

The reflectance of the phase shift films of the phase shift mask blanks of Example 1 and Comparative Example 1 was measured by a spectrophotometer U-4100 manufactured by Hitachi High-Technologies Corporation.
As a result, the reflectance spectrum of Example 1 at a wavelength 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 could be obtained even if the phase shift film was formed under the condition of downstream supply of the sputtering gas.

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, A photoresist film 5 was applied on the phase shift films 3 of the phase shift mask blanks of Example 1 and Comparative Example 1 using a resist coating device.
After that, a photoresist film 5 having a thickness of 1000 nm was formed through a heating / cooling process.
Thereafter, the photoresist film 5 is drawn using a laser drawing device, and after a development and rinsing step, a line and line pattern having a width of 2.0 μm and a space pattern of 2.0 μm is formed on the phase shift film 3. A resist film pattern 5 'having a space pattern was formed.

  Thereafter, using the resist film pattern 5 'as a mask, the phase shift film 3 was wet-etched with a chromium etchant containing ceric ammonium nitrate and perchloric acid to form a phase shift film pattern 3'.

  Thereafter, the resist film pattern 5 'was peeled off.

  Thus, the phase shift mask 30 (transparent substrate / phase shift) of the first embodiment in which the phase shift film pattern 3 ′ obtained by patterning the phase shift film 3 that has not been subjected to the VUV irradiation process is formed on the transparent substrate 2 is formed. Film pattern) and the phase shift mask of Comparative Example 1 (transparent substrate / phase shift film pattern).

The cross section to be etched of the edge portion of each phase shift film pattern 3 'of the phase shift mask 30 of Example 1 and the phase shift mask of Comparative Example 1 was observed by a scanning electron microscope before the resist film pattern 5' was peeled off. .
FIG. 10 is a cross-sectional photograph of the edge of the phase shift film pattern 3 ′ of the phase shift mask of Example 1, and FIG. 11 is a cross-sectional photograph of the edge of the phase shift film pattern of the phase shift mask of Comparative Example 1. FIG. 12 is a cross-sectional view for explaining a cross-sectional angle (θ) serving as a judgment index of a cross-sectional shape of an edge portion.
In FIG. 12, the thickness of the phase shift film 3 is denoted by T, the auxiliary line drawn from the outermost surface to a depth of T / 10 is denoted by L1, and drawn from the main surface side of the transparent substrate 2 to the height of T / 10. The auxiliary line is denoted by L2, the intersection of the cross section F to be etched of the phase shift film 3 with the auxiliary line L1 is denoted by C1, and the intersection of the etched cross section F and the auxiliary line L2 is denoted by C2. Here, the cross-sectional angle (θ) is an angle formed by a connecting line connecting the intersection C1 and the intersection C2 and the main surface of the transparent substrate 2.
The resist interface angle is an angle formed by the etched section F near the resist and the outermost surface, and the transparent substrate interface angle is an angle formed by the etched section F near the transparent substrate and the main surface of the transparent substrate.
Further, the length of the tapered lower surface is defined as a point at which one point of the intersection of the cross section F to be etched near the resist and the outermost surface is projected vertically on the main surface of the transparent substrate as it is, and It is the length of one point at the tip of the hem.

In FIG. 10, the resist interface angle of the cross section to be etched at the edge portion of Example 1 is 100 degrees, the transparent substrate interface angle is 50 degrees, the taper lower surface length is 50 nm, and the cross section angle (θ) is 80 degrees. Degree.
On the other hand, the resist interface angle of the cross section to be etched at the edge portion of Comparative Example 1 shown in FIG. 11 is 155 degrees, the transparent substrate interface angle is 25 degrees, the taper lower surface length is 200 nm, and the cross-sectional angle (θ) Was 25 degrees. The cross section to be etched in Comparative Example 1 had a tapered shape with a longer skirt than the cross section to be etched in Example 1.
As is clear from these results, it was found that the cross section to be etched in Example 1 had a significantly larger cross section angle (θ) than the cross section to be etched in Comparative Example 1, and was closer to a vertical cross section. That is, by forming the phase shift film under the downstream supply condition of the sputtering gas, the cross-sectional angle (θ) of the cross-section to be etched at the edge portion increases.

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 Nanotechnology. The CD variation was measured at 5 × 5 points in an area of 740 mm × 860 mm 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 for measuring CD variations.
The CD variation was as good as 0.087 μm.

  The CD variation of the phase shift film pattern of the phase shift mask of Comparative Example 1 was 0.205 μm, which was larger than that of Example 1.

Next, light intensity distribution curves at a wavelength of 365 nm in Example 1 and Comparative Example 1 simulating the aerial images of light passing through a phase shift mask in which a phase shift film pattern having a 2.5 μm square contact hole pattern was formed ( Transmittance 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, and has a large light intensity change at the pattern boundary portion, and a light intensity change at a peripheral region outside the pattern boundary portion. The change was small. Therefore, it was found that the phase shift mask of Example 1 exhibited a higher light intensity gradient and higher resolution than Comparative Example 1.

Example 2 and Comparative Example 2.
In Example 2 and Comparative Example 2, unlike Example 1 and Comparative Example 1, a phase shift mask blank having a phase shift film (material: CrOCN) subjected to a VUV irradiation process performed after the phase shift film 3 was formed. A phase shift mask manufactured using this phase shift mask blank will be described.
The phase shift mask blank 1 of the second embodiment is manufactured by depositing the phase shift film 3 under the downstream supply conditions of the sputtering gas and then performing the VUV irradiation treatment, as in the first embodiment. On the other hand, the phase shift mask blank of Comparative Example 2 is manufactured by forming the phase shift film under the upstream supply condition of the sputtering gas and then performing the VUV irradiation treatment similarly to Comparative Example 1. , They are different.

A. Phase Shift Mask Blank and Manufacturing Method Thereof As a transparent substrate 2, a synthetic quartz glass substrate having the same size as in Example 1 was prepared.
In the second embodiment, in the phase shift film forming step, the same components as in the first embodiment are supplied to the sputtering apparatus 11 shown in FIG. 2 from the second gas inlet GA12 disposed downstream of the first sputter target 13 made of chromium. Was introduced at the same flow rate as in Comparative Example 1 (Ar: 46 sccm, N ₂ : 46 sccm, CO ₂ : 35 sccm), and the sputtering power was 3.55 kw. The other film forming conditions were the same as in Example 1, and the phase shift film 3 (film thickness 125 nm) was formed by one film formation.
On the other hand, in Comparative Example 2, the phase shift film forming step was performed under the same film forming conditions as in Comparative Example 1, and a phase shift film (125 nm thick) was formed by one film formation.

Thereafter, VUV irradiation treatment was performed on the outermost surfaces of the phase shift films of Example 2 and Comparative Example 2.
For the VUV irradiation treatment, an irradiation device (not shown) for irradiating VUV (xenon excimer light, wavelength 172 nm) with energy of 40 mW / cm ² was used, and irradiation energy of 45 J / cm ^{2 was} applied to the outermost surface of the phase shift film 3. Irradiation corresponding to.
In this manner, the phase shift mask blank 1 of the second embodiment in which the phase shift film 3 subjected to the VUV irradiation treatment is formed, and the phase shift mask blank of the comparative example 2 in which the phase shift film subjected to the VUV irradiation treatment is formed I got

  The phase shift films of the phase shift mask blanks of Example 2 and Comparative Example 2 were subjected to composition analysis in the depth direction by X-ray photoelectron spectroscopy (XPS). It was found that the content of each element (Cr, C, O, N) showed the same tendency as in Example 1.

  Next, as in Example 1, the values of the refractive index (n) and the extinction coefficient (k) of the phase shift film of Example 2 were measured by a spectroscopic ellipsometer. The MSE of Example 2 was 4.498, and the MSE of Comparative Example 2 was 4.505.

FIG. 13 is a diagram showing the relationship between the refractive index (n) at the wavelength of 190 nm to 1000 nm with respect to the main layer upper part and the main layer lower part of the phase shift film 3 of Example 2, and FIG. FIG. 15 is a diagram showing the relationship between the refractive index (n) at a wavelength of 190 nm to 1000 nm with respect to the upper layer and the lower layer. FIG. 15 shows the relationship from the outermost surface layer of the phase shift film of the phase shift mask blank of Example 2 and Comparative Example 2. It is a figure which shows the refractive index in wavelength 365nm with respect to a layer lower part.
As shown in FIG. 13, it was found that in the wavelength range, the refractive index of the upper part of the main layer of the phase shift film 3 in the phase shift mask blank 1 of Example 2 was smaller than the refractive index of the lower part of the main layer. In particular, at the i-line (wavelength 365 nm), which is one of the wavelengths of the exposure light source (ultra-high pressure mercury lamp: mixed light of i-line, h-line, and g-line) used in manufacturing a display device, the upper part of the main layer is The refractive index was 2.43, and the refractive index under the main layer was 2.57.
On the other hand, as shown in FIG. 14, in the wavelength range, the refractive index of the upper part of the main layer of the phase shift film in the phase shift mask blank of Comparative Example 2 was found to be substantially the same as the refractive index of the lower part of the main layer. . In particular, at the i-line (wavelength 365 nm), the refractive index of the upper portion of the main layer was 2.59, and the refractive index of the lower portion of the main layer was 2.57.
As shown in FIG. 15, in the second embodiment, similarly to the first embodiment, the refractive index at the wavelength of 365 nm decreases in the outermost surface layer 3b of the phase shift film 3, and the refractive index at the wavelength of 365 nm in the main layer 3a. On the other hand, in Comparative Example 2, as in Comparative Example 1, the refractive index at a wavelength of 365 nm increased in the outermost surface layer of the phase shift film, and the refractive index at a wavelength of 365 nm in the main layer. Showed a tendency to decrease. As is clear from these results, in Example 2 in which the phase shift film 3 was formed by using the downstream supply condition of the sputtering gas, the phase shift film was formed by using the upstream supply condition of the sputtering gas. Compared with Example 2, even when the VUV irradiation treatment was performed, it was found that the change tendency of the refractive index in the depth direction of the phase shift film was exactly opposite to the relationship between Example 1 and Comparative Example 1.
Further, in Example 2 shown in FIG. 15, the maximum value of the refractive index at the wavelength of 365 nm of the outermost surface layer 3b of the phase shift film 3 is about 2 compared to Example 1 in FIG. From 0.77 to about 2.70, it was found that the tendency of decrease in the refractive index was reduced, and the tendency of increase in the refractive index of the main layer 3a at a wavelength of 365 nm was reduced.
On the other hand, in Comparative Example 2 shown in FIG. 15, the maximum value of the refractive index at the wavelength of 365 nm, for example, of the outermost surface layer of the phase shift film is about 2.0 compared to Comparative Example 1 in FIG. 9 in which the VUV irradiation step is not performed. From 5 to about 2.38, it was found that the tendency of the increase in the refractive index was increased, and the tendency of the main layer to decrease in the refractive index at a wavelength of, for example, 365 nm was reduced or substantially flat.

With respect to the phase shift films of the phase shift mask blanks of Example 2 and Comparative Example 2, the film density on the outermost surface was measured by X-ray reflectivity analysis (XRR) as in Example 1. The film density on the outermost surface of Example 2 was 2.33 g / cm ³ , and the film density on the outermost surface of Comparative Example 2 was 2.29 g / cm ³ . The numerical index Fit R indicating the validity of the fitting when calculating the film density was 0.013 in Example 2 and 0.012 in Comparative Example 2.

Next, in the same manner as in Example 1, the transmittance, the reflectance, and the phase difference of the phase shift films of the phase shift mask blanks of Example 2 and Comparative Example 2 were measured.
As a result, the transmittance at a wavelength of 365 nm in Example 2 was 5.1%, the phase difference at a wavelength of 365 nm in Example 2 was 182.0 degrees, and the reflectance spectrum of Example 2 was the same as that of Example 1. It was almost the same.
On the other hand, the transmittance of Comparative Example 2 at a wavelength of 365 nm is 5.4%, the phase difference of Comparative Example 2 at a wavelength of 365 nm is 181.5 degrees, and the reflectance spectrum of Comparative Example 2 is substantially the same as that of Example 1. It was similar.

B. Phase shift mask and manufacturing method thereof Using the phase shift mask blanks of Example 2 and Comparative example 2 manufactured as described above, the phase shift masks of Example 2 and Comparative example 2 were formed in the same manner as in Example 1. Manufactured.

In this manner, the phase shift mask 30 (transparent substrate / phase shift film) of the second embodiment in which the phase shift film pattern 3 ′ obtained by patterning the phase shift film 3 subjected to the VUV irradiation process is formed on the transparent substrate 2. Pattern).
On the other hand, in the same manner as in Example 2, the phase shift mask of Comparative Example 2 in which a phase shift film pattern obtained by patterning a phase shift film subjected to a VUV irradiation process was formed on the transparent substrate 2 (transparent substrate / phase Shift film pattern).

  The cross sections to be etched at the edge portions of the phase shift film patterns of the phase shift masks of Example 2 and Comparative Example 2 were observed with a scanning electron microscope before the resist film pattern was stripped.

The resist interface angle of the etched section of the edge portion of Example 2 shown in FIG. 16 is 90 degrees, the transparent substrate interface angle is 90 degrees, the length of the tapered lower surface is 0 nm, and the cross-sectional angle (θ) is 90 degrees. Degree.
As is clear from this result, the cross section to be etched in Example 2 had a larger cross-sectional angle (θ) than the cross section to be etched in Example 1, and was closer to a vertical cross-sectional shape. That is, the VUV irradiation process increases the cross-sectional angle (θ) of the cross-section to be etched at the edge portion.

The resist interface angle of the etched section of the edge portion of Comparative Example 2 shown in FIG. 17 is 130 degrees, the transparent substrate interface angle is 50 degrees, the taper lower surface length is 80 nm, and the cross-sectional angle (θ) is 50 degrees. Degree.
As is clear from this result, the cross section to be etched in Comparative Example 2 has a larger cross-sectional angle (θ) than the cross section to be etched in Comparative Example 1, the length of the tapered lower surface is shorter, and the cross section is slightly vertical. I found it approaching. That is, the VUV irradiation process increases the cross-sectional angle (θ) of the cross-section to be etched at the edge portion.

Next, CD variations of the phase shift film patterns of the phase shift masks of Example 2 and Comparative Example 2 were measured as in Example 1.
The CD variation of Example 2 was as good as 0.059 μm. As is clear from these results, it was found that the CD variation of Example 2 was even smaller than the CD variation of Example 1 which was not subjected to the VUV irradiation step.
On the other hand, the CD variation of Comparative Example 2 was 0.156 μm. As is clear from the results, the CD variation of Comparative Example 2 is smaller than the CD variation of Comparative Example 1 not subjected to the VUV irradiation step, but is smaller than the CD variation of Examples 1 and 2 in the downstream supply condition of the sputtering gas. It turned out to be much larger.

Next, as in Example 1, a light intensity distribution curve (transmittance profile) at a wavelength of 365 nm was examined.
The light intensity distribution curve of Example 2 has a sharper peak intensity at the center of the contact hole as compared with Comparative Example 2, and has a large change in light intensity at the pattern boundary portion, and a light intensity change in a peripheral region outside the pattern boundary portion. The change was small. Therefore, it was found that the phase shift mask of Example 2 exhibited a higher light intensity gradient and higher resolution than Comparative Example 2.

Example 3 and Comparative Example 3.
In Example 3 and Comparative Example 3, a phase shift mask blank having the phase shift film 3 (material: CrON) and a phase shift mask manufactured using the phase shift mask blank will be described.
The phase shift mask blank 1 of the third embodiment is manufactured by forming the phase shift film 3 under the downstream supply condition of the sputtering gas in the same manner as in the first embodiment. The shift mask blank differs from the shift mask blank in that the phase shift film is manufactured by forming the phase shift film under the upstream supply condition of the sputtering gas, as in Comparative Example 1.

A. Phase Shift Mask Blank and Manufacturing Method Thereof As a transparent substrate 2, a synthetic quartz glass substrate having the same size as in Example 1 was prepared.
Thereafter, the transparent substrate 2 is introduced into the in-line type sputtering apparatus 11 shown in FIG. 2, and a phase shift film 3 (157 nm thick) made of chromium oxynitride (CrON) is formed once on the main surface of the transparent substrate 2. To obtain a phase shift mask blank 1.
The phase shift film 3 is supplied from a second gas inlet GA12 downstream of the first sputter target 13 made of chromium from a mixed gas containing argon (Ar) gas and nitric oxide (NO) gas (Ar: 46 sccm, NO: (50 sccm) was introduced, the sputtering power was set to 3.5 kw, the transport speed of the transparent substrate 2 was set to 400 mm / min, and one film was formed on the transparent substrate 2 by reactive sputtering.

  On the other hand, in Comparative Example 3, in the phase shift film forming step, the sputtering apparatus 11 shown in FIG. A mixed gas of the same components was introduced, and the sputtering power was 7.85 kw. The other film forming conditions were the same as in Example 3, and the phase shift film 3 (film thickness: 157 nm) was formed by a single film formation to obtain the phase shift mask blank of Comparative Example 3.

  The composition of the phase shift films of the phase shift mask blanks of Example 3 and Comparative Example 3 in the depth direction was analyzed by XPS. In each of Example 3 and Comparative Example 3, each element in the depth direction ( It was found that the content of (Cr, O, N) was substantially constant in the main layer, and changed in the same manner as in Example 1 in the outermost layer and the interface region near the transparent substrate 2.

  Next, as in Example 1, the values of the refractive index (n) and the extinction coefficient (k) of the phase shift films 3 of Example 3 and Comparative Example 3 were measured with a spectroscopic ellipsometer. The MSE of Example 3 was 4.458, and the MSE of Comparative Example 3 was 4.500.

Next, in the same manner as in Example 1, the refractive index, the transmittance, the reflectance, and the phase difference of the phase shift films of the phase shift mask blanks of Example 3 and Comparative Example 3 were measured.
As a result, the refractive index of the upper portion of the main layer was 2.42 and the refractive index of the lower portion of the main layer was 2.56 at the i-line (wavelength 365 nm) in Example 3. The transmittance at a wavelength of 365 nm in Example 3 was 5.6%, the phase difference at a wavelength of 365 nm in Example 3 was 179 degrees, and the reflectance spectrum of Example 3 was substantially the same as that of Example 1. .
On the other hand, the refractive index of the upper part of the main layer at the i-line (wavelength 365 nm) of Comparative Example 3 was 2.61 and the refractive index of the lower part of the main layer was 2.49. The transmittance of Comparative Example 3 at a wavelength of 365 nm was 6.0%, the phase difference of Comparative Example 3 at a wavelength of 365 nm was 178 degrees, and the reflectance spectrum of Comparative Example 3 was substantially the same as that of Example 3. .

The film density of the outermost surfaces of the phase shift films of the phase shift mask blanks of Example 3 and Comparative Example 3 was measured by X-ray reflectivity analysis (XRR) in the same manner as in Example 1. film density of the surface was 1.84 g / cm ^3, the film density of the outermost surface of Comparative example 3 was 1.82 g / cm ^3. The numerical index Fit R indicating the validity of the fitting when calculating the film density was 0.011 in Example 3 and 0.013 in Comparative Example 3.

B. Phase shift mask and manufacturing method thereof Using the phase shift mask blanks of Example 3 and Comparative example 3 manufactured as described above, the phase shift masks of Example 3 and Comparative example 3 were manufactured in the same manner as in Example 1. Manufactured.

In this manner, a phase shift film pattern 3 ′ was formed on the transparent substrate 2 under the conditions of the downstream supply of the sputtering gas, and the phase shift film 3 obtained by not subjecting to the VUV irradiation step was patterned. A phase shift mask 30 (transparent substrate / phase shift film pattern) of Example 3 was obtained.
On the other hand, the phase shift film of Comparative Example 3 was formed on the transparent substrate 2 under the upstream supply condition of the sputtering gas, and the phase shift film pattern was formed by patterning the phase shift film obtained without receiving the VUV irradiation step. A mask (transparent substrate / phase shift film pattern) was obtained.

  Before the resist film pattern was peeled off, the cross sections to be etched at the edges of the phase shift film patterns of the phase shift masks of Example 3 and Comparative Example 3 were observed with a scanning electron microscope.

In Example 3, the resist interface angle of the cross section to be etched at the edge portion was 105 degrees, the transparent substrate interface angle was 45 degrees, the length of the tapered lower surface was 65 nm, and the cross section angle (θ) was 75 degrees. .
On the other hand, the resist interface angle of the cross section to be etched at the edge portion of Comparative Example 3 was 140 degrees, the transparent substrate interface angle was 40 degrees, the length of the tapered lower surface was 150 nm, and the cross section angle (θ) was 40 degrees. there were.
As is clear from these results, the cross section to be etched in Example 3 has a significantly larger cross section angle (θ) than the cross section to be etched in Comparative Example 3, and the cross sectional shape of Comparative Example 3 is It turns out that it becomes a taper shape which pulls a longer hem.

Next, CD variations of the phase shift film patterns of the phase shift masks of Example 3 and Comparative Example 3 were measured as in Example 1.
The CD variation of Example 3 was as good as 0.106 μm, whereas the CD variation of Comparative Example 3 was 0.175 μm.

Next, as in Example 1, a light intensity distribution curve (transmittance profile) at a wavelength of 365 nm was examined.
The light intensity distribution curve of Example 3 has a sharp peak intensity at the center of the contact hole as compared with Comparative Example 3, a large change in light intensity at a pattern boundary portion, and a large light intensity change in a peripheral region outside the pattern boundary portion. The change was small. Therefore, it was found that the phase shift mask of Example 3 exhibited a higher light intensity gradient and higher resolution than Comparative Example 3.

Embodiment 4. FIG.
In the fourth embodiment, as in the third embodiment, the phase shift mask blank including CrON as a constituent material and having the phase shift film 3 subjected to the VUV irradiation treatment, as in the second embodiment, and the phase shift mask blank A phase shift mask manufactured using the method will be described.

A. Phase Shift Mask Blank and Manufacturing Method Thereof As a transparent substrate 2, a synthetic quartz glass substrate having the same size as in Example 1 was prepared.
Thereafter, the transparent substrate 2 is introduced into the in-line type sputtering apparatus 11 shown in FIG. 2, and a phase shift film 3 (157 nm thick) made of chromium oxynitride (CrON) is formed once on the main surface of the transparent substrate 2. To obtain a phase shift mask blank 1.
The phase shift film 3 is supplied from a second gas inlet GA12 downstream of the first sputter target 13 made of chromium from a mixed gas containing argon (Ar) gas and nitrogen monoxide (NO) gas (Ar: 46 sccm, NO: 70 sccm), the sputtering power was set to 8.0 kW, and the transport speed of the transparent substrate 2 was set to 400 mm / min.
After that, VUV irradiation processing was performed on the outermost surface of the phase shift film 3 under the same irradiation conditions as in Example 2.

  Thus, the phase shift mask blank 1 in which the phase shift film 3 subjected to the VUV irradiation treatment was formed on the transparent substrate 2 was obtained.

  The composition of the phase shift film 3 of the phase shift mask blank 1 of Example 4 in the depth direction was analyzed by XPS. As a result, the content of each element (Cr, O, N) in the depth direction was determined. It turned out that it shows the same change tendency as.

  Next, as in Example 1, the values of the refractive index (n) and the extinction coefficient (k) of the phase shift film 3 of Example 3 were measured with a spectroscopic ellipsometer. The MSE of Example 4 was 4.489.

Next, similarly to Example 1, the refractive index, transmittance, reflectance, and phase difference of the phase shift film 3 of the phase shift mask blank 1 of Example 4 were measured.
As a result, the refractive index of the upper part of the main layer was 2.45 and the refractive index of the lower part of the main layer was 2.53 at the i-line (wavelength 365 nm) in Example 4. The transmittance at a wavelength of 365 nm of Example 4 was 5.7%, the phase difference at a wavelength of 365 nm of Example 4 was 179 degrees, and the reflectance spectrum of Example 4 was substantially the same as that of Example 3. .

The film density of the outermost surface of the phase shift film 3 of the phase shift mask blank 1 of Example 4 was measured by X-ray reflectivity analysis (XRR) in the same manner as in Example 1, and the film density of the outermost surface was , 2.19 g / cm ³ . The numerical index Fit R indicating the validity of the fitting when calculating the film density was 0.013 in Example 4.

B. Phase Shift Mask and Manufacturing Method Thereof A phase shift mask 30 having a phase shift film pattern 3 ′ formed by patterning the phase shift film 3 subjected to the VUV irradiation process on the transparent substrate 2 is formed by the same method as in the first embodiment. 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 4 was observed by a scanning electron microscope before the resist film pattern 5' was peeled off.
As a result, in Example 4, the resist interface angle of the cross section to be etched at the edge portion was 90 degrees, the transparent substrate interface angle was 90 degrees, the taper lower surface length was 0 nm, and the cross section angle (θ) was 90 degrees. Met. In other words, the cross section to be etched of the phase shift film pattern 3 ′ of Example 4 using CrON as a constituent material and subjected to the VUV irradiation treatment is the phase shift film of Example 3 using CrON as the constituent material and not subjected to the VUV irradiation step. Similar to the cross section to be etched of the pattern 3 ', there was no skirt at all, and the cross section was completely vertical.

Next, CD variation of the phase shift film pattern of the phase shift mask 30 of Example 4 was measured in the same manner as in Example 1.
The CD variation was as good as 0.062 μm.

Next, as in Example 1, a light intensity distribution curve (transmittance profile) at a wavelength of 365 nm was examined.
The light intensity distribution curve of Example 4 showed a strong light intensity gradient similarly to the phase shift mask of Example 2, indicating that the resolution was high.

In the above-described embodiment, the example of the phase shift mask blank 1 in which the phase shift film 3 formed on the transparent substrate 2 is a single-layer film has been described, but the present invention is not limited to this. Even if the phase shift film 3 is a laminated film having the same material, such as a two-layer structure, a three-layer structure, and a four-layer structure, the same effects as those of the above embodiment can be obtained.
In the above-described embodiment, the phase shift mask blank 1 in which only the phase shift film 3 is formed on the transparent substrate 2 and the phase shift mask 30 in which only the phase shift film pattern 3 ′ is formed on the transparent substrate 2 are described. Although described, it is not limited to this. Even in the case of the phase shift mask blank 10 (see FIG. 4) having the light shielding film pattern 4 ′ and the phase shift film 3 on the transparent substrate 2, the phase shift mask blank having the phase shift film 3 and the resist film 5 on the transparent substrate 2 In the case of (see FIG. 5B), the phase shift mask 31 having the light-shielding film pattern 4 ′ and the phase shift film pattern 3 ′ on the transparent substrate 2 (see FIG. 6E) is similar to the above embodiment. Has the effect of
Further, in a phase shift mask blank (not shown) having the phase shift film 3 and the light shielding film 4 on the transparent substrate 2, the light shielding film 4 formed on the phase shift film 3 is replaced by a light shielding layer, a light shielding layer, and an anti-reflection layer. May be used.

Further, in the above-described embodiments, examples of the phase shift mask blank for manufacturing the display device and the example of the phase shift mask for manufacturing the display device have been described. However, the present invention is not limited to this. The phase shift mask blank and the phase shift mask of the present invention can be applied to semiconductor device manufacturing, MEMS (microelectromechanical system) manufacturing, printed circuit board, and the like.
Further, in the above-described embodiment, an example is described in which the size of the transparent substrate is 8092 size (800 mm × 920 mm). However, the size is not limited to this and may be another size. 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 has a side length of 10 inches or more. The size of the transparent substrate used is, for example, not less than 330 mm × 450 mm and not more than 2280 mm × 3130 mm.
Further, in the case of a phase shift mask blank for semiconductor device manufacturing, MEMS manufacturing, and printed circuit board, a small transparent substrate is used, and the size of the transparent substrate is 9 inches or less on one side. The size of the transparent substrate used for the phase shift mask blank for the above application is, for example, 63.1 mm × 63.1 mm or more and 228.6 mm × 228.6 mm or less. Usually, 6025 size (152 mm × 152 mm) or 5009 size (126.6 mm × 126.6 mm) is used for semiconductor manufacturing and MEMS manufacturing, and 7012 size (177.4 mm × 177.4 mm) for printed circuit boards. Alternatively, a 9012 size (228.6 mm × 228.6 mm) is used.

1, 10 phase shift mask blank, 2 transparent substrate, 3 phase shift film,
3a main layer, 3b outermost layer, 4 light shielding film, 5 resist film, 3 'phase shift film pattern,
4 'light-shielding film pattern, 5' resist film pattern,
F section to be etched, C1, C2 intersection, T film thickness, θ section angle,
11 sputtering equipment, LL loading chamber,
SP1 first sputter chamber, BU buffer chamber,
SP2 2nd sputter chamber, UL unloading 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,
15 third sputter target, GA31 fifth gas inlet,
GA32 sixth gas inlet, 30, 31 phase shift mask.

Claims (7)

A phase shift mask blank in which a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate,
The phase shift film is made of a material composed of chromium, oxygen, nitrogen, and carbon, and the composition ratio of each element in the film depth direction is such that the fluctuation range of chromium is ± 5. 0 atomic%, the fluctuation range of oxygen is ± 6.5 atomic% with respect to the central content of oxygen, the fluctuation range of nitrogen is ± 4.5 atomic% with respect to the central content of nitrogen , A main layer whose variation width is within ± 4.0 atomic% with respect to a central content of carbon, and a top surface layer which is a surface oxide layer of the main layer;
In the outermost surface layer, the oxygen content increases toward the film surface side, and the film density is 2.0 g / cm ³ or more,
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 by a spectral ellipsometer is smaller than a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side.   2. The phase shift according to claim 1, wherein the refractive index at a wavelength of 365 nm below the main layer is 2.50 or more, and the refractive index at a wavelength of 365 nm above the main layer is 2.45 or less. Mask blank.   3. The phase shift according to claim 1, wherein a difference 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 0.05 or more and 0.25 or less. Mask blank. Chrome 35 atomic% to 60 atomic% of chromium, 15 atomic% to 45 atomic%, nitrogen 25 atom% 5 atom% or less, and wherein the carbon is 15 atomic% or less 2 atomic% or more The phase shift mask blank according to any one of claims 1 to 3 . A method for producing a phase shift mask blank in which a phase shift film containing chromium, oxygen, and nitrogen is formed on a transparent substrate by a sputtering method using an inline-type sputtering apparatus,
The phase shift film has a main layer made of chromium, oxygen, nitrogen, and carbon, and an outermost surface layer of surface oxidation,
The composition ratio of each element in the film depth direction of the main layer is such that the variation range of chromium is ± 5.0 atomic% with respect to the central content of chromium, and the variation range of oxygen is the central content of oxygen. ± 6.5 atomic%, the fluctuation range of nitrogen ± 4.5 atomic% with respect to the central content of nitrogen, and the fluctuation range of carbon ± 4 with respect to the central content of carbon. Within 0 atomic%,
The main layer is formed by using a sputtering target containing chromium and performing reactive sputtering using an inert gas and a mixed gas containing an active gas of carbon dioxide (CO ₂ ) gas and nitrogen (N ₂ ) gas. The mixed gas 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,
A phase characteristic wherein a refractive index at a wavelength of 365 nm above the main layer on the outermost surface layer side by a spectral ellipsometer is smaller than a refractive index at a wavelength of 365 nm below the main layer on the transparent substrate side. Manufacturing method of shift mask blank. After the film forming step, the outermost surface of the phase shift film is subjected to a vacuum ultraviolet light irradiation step of performing a vacuum ultraviolet light irradiation treatment, so that the film density of the outermost surface of the phase shift film is 2.0 g / cm ^3. The method for manufacturing a phase shift mask blank according to claim 5, wherein: A resist is provided on the phase shift film of the phase shift mask blank according to any one of claims 1 to 4 , or a phase shift mask blank manufactured by the method of manufacturing a phase shift mask blank according to claim 5 or 6. A method for manufacturing a phase shift mask, comprising: forming a film pattern; and wet etching the phase shift film using the resist film pattern as a mask to form a phase shift film pattern on the transparent substrate.

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