Phase shift mask blanks, phase shift masks, and manufacturing methods

Abstract

To improve adhesion between a phase shift layer and a resist layer and also improve shape accuracy of a phase shift pattern.SOLUTION: A phase shift mask blank 10B includes a mask layer to be a phase shift mask 10, wherein the phase shift mask blank includes a phase shift layer 12 which is laminated on a transparent substrate 11 and contains chromium, oxygen and carbon, wherein the phase shift layer has an oxygen level of 70% or more over the entire area in its thickness direction, and the phase shift layer includes a high carbon region 12c having a carbon level of 3.5 atm% or more on a surface remote from the transparent substrate in the thickness direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a phase shift mask blank, a phase shift mask, and a technique suitable for use in a manufacturing method thereof. [Background technology]

[0002] 2. Description of the Related Art In the manufacture of FPDs (flat panel displays) such as liquid crystal displays and organic EL displays, or in the manufacture of semiconductor devices, a mask layer is used in a photoresist process. In this case, a mask blank in which a mask layer made of a chromium compound is formed on a quartz substrate may be used as the mask layer.

[0003] Here, wet etching is generally used for patterning large masks used in FPDs, etc. In this wet etching process, a resist layer is laminated on a mask layer made of a chromium-based material, the resist layer is patterned, and then the mask is immersed in or sprayed with a chromium etchant to perform etching, thereby forming a patterned mask layer. This produces a photomask in which a light-transmitting region where no exposed pattern is arranged on the transparent substrate and a light-shielding region where a light-shielding layer is laminated on the transparent substrate are arranged adjacent to each other (Patent Document 1).

[0004] In recent years, the trend toward higher resolution has progressed significantly, and photomasks have also become increasingly miniaturized. This has led to a growing need for edge-enhancing phase-shift masks in addition to conventional masks that use light-shielding films. Conventionally, phase shift masks are required to have a high contrast during exposure, so rim-type phase shift masks have been used, in which a phase shift layer made of a chromium compound is formed as a mask layer on a quartz substrate, and a light-shielding layer (binary layer) made of a metal film such as a chromium film is formed on top of that. In this case, it is known to use a silicide film such as a molybdenum silicide film as an etching stop film used in the wet etching (Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-008114 [Patent Document 2] International Publication No. 2013 / 190786 Summary of the Invention [Problem to be solved by the invention]

[0006] However, unlike semiconductor device manufacturing, in recent years, in FPD manufacturing, these fine patterns are sometimes formed using phase shift masks called Cr-PSM, which are phase shift masks in which a single chromium-based phase shift layer is laminated on a glass substrate. This is because the recent progress in high-definition displays for smartphones and other devices has led to a demand for the formation of fine patterns in display masks, and Cr-PSM uses only a chromium film as the mask material, making it possible to form fine patterns relatively easily by using the phase shift effect.

[0007] Thus, in a phase shift mask blank having a chromium-based mask layer, if the adhesion between the resist layer and the chromium-based mask layer is insufficient, the etchant will seep into the gap between the resist layer and the chromium-based mask layer, deteriorating the shape of the mask pattern that is formed. There has been a strong demand for improving this, particularly when the mask layer is formed as a single chromium-based layer.

[0008] The present invention has been made in view of the above circumstances, and aims to achieve the following objects. 1. To improve adhesion with the resist layer while maintaining the optical properties of the mask layer. 2. To improve the definition of the pattern shape when patterning a mask layer by wet etching. [Means for solving the problem]

[0009] The inventors of the present application have considered the cause of the deterioration of the adhesion between the phase shift layer and the resist layer, which allows the etchant to penetrate and destroy the patterned shape, as follows.

[0010] A phase shift layer made of a chromium compound contains a very high amount of oxygen to provide the necessary phase shifting ability and other optical properties. Therefore, the oxygen concentration at the surface that must adhere to the resist layer is also high. This results in a high hydrophilicity at the surface of the phase shift layer made of a chromium compound, which reduces adhesion to the resist layer.

[0011] Therefore, during the wet etching process, the etchant penetrates between the chromium-based mask layer and the resist layer, and etching proceeds near this interface, resulting in the removal of unnecessary portions. As a result, along the edges of the resist pattern, sloped portions are formed below the resist pattern on the side surfaces of the mask layer extending in the film thickness direction, which are expected to be formed perpendicular to the glass substrate surface. In other words, the accuracy of the pattern shape of the phase shift pattern is reduced due to these cutout portions.

[0012] Therefore, to maintain the accuracy of the phase-shift pattern, it is necessary to improve the adhesion between the phase-shift layer and the resist layer. To achieve this, we considered that improving the hydrophobicity of the phase-shift layer surface, i.e., increasing the contact angle with water on the phase-shift layer surface, would be effective. At the same time, it is important to maintain the phase-shifting ability and optical properties of the entire phase-shift layer without changing them. Taking these points into consideration, the inventors of the present invention have completed the present invention as follows.

[0013] (1) A phase shift mask blank according to one aspect of the present invention, A phase shift mask blank having a mask layer that serves as a phase shift mask, a phase shift layer containing chromium, oxygen, and carbon deposited on a transparent substrate; the phase shift layer has an oxygen concentration of 70% or more throughout the entire thickness direction; the phase shift layer has a high carbon region with a carbon concentration of 3.5 atm% or more on a surface thereof separated from the transparent substrate in a thickness direction thereof; This solved the above problem. (2) The phase shift mask blank of the present invention, in the above (1), the high-carbon region in the phase shift layer has a thickness of 10 nm or less in a film thickness direction; It is possible. (3) The phase shift mask blank of the present invention is characterized in that, in the above (1) or (2), the contact angle of water on the surface of the high carbon region in the phase shift layer is 50 degrees or more; It is possible. (4) The phase shift mask blank of the present invention is any one of the above (1) to (3), the phase shift layer is located on the outermost surface of the mask layer laminated on the transparent substrate; It is possible. (5) Another aspect of the present invention provides a method for producing a phase shift mask blank according to any one of (1) to (4) above, comprising the steps of: a phase shift layer forming step of laminating the phase shift layer containing chromium and oxygen on the transparent substrate, In the phase shift layer forming step, the high carbon region is formed by incorporating carbon into the surface of the phase shift layer to be laminated. It is possible. (6) The method for producing a phase shift mask blank of the present invention comprises the steps of: In the phase shift layer forming step, a partial pressure of a carbon-containing gas is set as a supply gas in sputtering to contain carbon in the surface of the phase shift layer, thereby forming the high-carbon region; It is possible. (7) A phase shift mask according to another aspect of the present invention is a phase shift mask manufactured from a phase shift mask blank according to any one of (1) to (4) above, or manufactured by a method for manufacturing a phase shift mask blank according to (5) or (6) above, In the mask pattern, the phase shift pattern formed from the phase shift layer has an oxygen concentration of 70% or more throughout the entire region in the film thickness direction, and has a high carbon region with a carbon concentration of 3.5 atm% or more on a surface separated from the transparent substrate in the film thickness direction. It is possible. (8) The phase shift mask of the present invention is the one described above in (7), the high carbon region in the phase shift pattern has a thickness of 10 nm or less in a film thickness direction; It is possible. (9) The phase shift mask of the present invention is the one described above in (7) or (8), the water contact angle of the surface of the high carbon region in the phase shift pattern is 50 degrees or more; It is possible. (10) A phase shift mask according to the present invention is any one of the above (7) to (9), the phase shift pattern is located on the outermost surface of the mask pattern laminated on the transparent substrate; It is possible. (11) Another aspect of the present invention provides a method for manufacturing a phase shift mask according to any one of (7) to (10) above, comprising the steps of: a resist pattern forming step of forming a resist pattern on the mask layer; a phase shift pattern forming step of forming a pattern in the phase shift layer; and In the phase shift pattern forming step, the high carbon region remains. It is possible.

[0014] (1) A phase shift mask blank according to one aspect of the present invention, A phase shift mask blank having a mask layer that serves as a phase shift mask, a phase shift layer containing chromium, oxygen, and carbon deposited on a transparent substrate; the phase shift layer has an oxygen concentration of 70% or more throughout the entire thickness direction; the phase shift layer has a high carbon region with a carbon concentration of 3.5 atm% or more on a surface thereof separated from the transparent substrate in a thickness direction thereof; This solved the above problem.

[0015] According to the above configuration, the high-carbon region on the surface of the phase shift layer improves the wettability of the surface of the phase shift layer while maintaining the optical properties of the phase shift layer, thereby improving the adhesion of the surface of the phase shift layer to the resist layer. This makes it possible to prevent an etchant from penetrating the interface between the phase shift layer and the resist layer during wet etching to form a phase shift pattern, which would otherwise cause the etching to progress and result in a decrease in the accuracy of the pattern shape of the phase shift pattern.

[0016] (2) The phase shift mask blank of the present invention, in the above (1), the high-carbon region in the phase shift layer has a thickness of 10 nm or less in a film thickness direction; It is possible.

[0017] According to the above configuration, the wettability of the surface of the phase shift layer can be improved while maintaining the optical properties of the phase shift layer, thereby improving the adhesion of the surface of the phase shift layer to the resist layer, thereby preventing the etchant from penetrating the interface between the phase shift layer and the resist layer during wet etching to form a phase shift pattern, which would otherwise cause the etching to progress and result in a decrease in the accuracy of the pattern shape of the phase shift pattern. Furthermore, since the high carbon region has the above-mentioned thickness, the high carbon region remains without being eliminated even by etching or cleaning in the pattern formation process, etc., and the properties of the phase shift layer or phase shift pattern surface can be maintained.

[0018] (3) The phase shift mask blank of the present invention is characterized in that, in the above (1) or (2), the contact angle of water on the surface of the high carbon region in the phase shift layer is 50 degrees or more; It is possible.

[0019] According to the above configuration, the wettability of the surface of the phase shift layer can be improved while maintaining the optical properties of the phase shift layer, thereby improving the adhesion of the surface of the phase shift layer to the resist layer, thereby preventing the etchant from penetrating the interface between the phase shift layer and the resist layer during wet etching to form a phase shift pattern, which would otherwise cause the etching to progress and result in a decrease in the accuracy of the pattern shape of the phase shift pattern. In particular, it is possible to improve the adhesion between the phase shift layer and the resist layer for resists that require hydrophobicity in order to improve adhesion, such as the GRX-M series resist materials from Nagase ChemteX Corporation, which are commonly used for metal etching in flat panel displays.

[0020] (4) The phase shift mask blank of the present invention is any one of the above (1) to (3), the phase shift layer is located on the outermost surface of the mask layer laminated on the transparent substrate; It is possible.

[0021] According to the above configuration, the wettability of the surface of the phase shift layer located at the outermost surface of the mask layer can be improved, and the adhesion of the surface of the phase shift layer to the resist layer can be improved while maintaining the optical properties of the phase shift layer. That is, the adhesion of the surface of the mask layer to the resist layer can be improved. This makes it possible to prevent an etchant from penetrating the interface between the mask layer and the resist layer during wet etching to form a phase shift pattern, i.e., a mask pattern as a photomask, and thus to prevent a decrease in the pattern shape accuracy of the mask pattern due to the progress of etching.

[0022] (5) Another aspect of the present invention provides a method for producing a phase shift mask blank according to any one of (1) to (4) above, comprising the steps of: a phase shift layer forming step of laminating the phase shift layer containing chromium and oxygen on the transparent substrate, In the phase shift layer forming step, the high carbon region is formed by incorporating carbon into the surface of the phase shift layer to be laminated. It is possible.

[0023] According to the above configuration, in a conventional phase shift layer formation process, a high-carbon region can be formed simply by incorporating carbon into the surface of the phase shift layer. This improves the wettability of the surface of the phase shift layer while maintaining the optical properties of the phase shift layer, thereby improving the adhesion of the surface of the phase shift layer to the resist layer. This makes it possible to manufacture phase shift mask blanks that do not suffer from a decrease in the pattern shape accuracy of the phase shift pattern due to the progress of etching caused by the penetration of etchant into the interface between the phase shift layer and the resist layer during wet etching to form a phase shift pattern.

[0024] Here, when carbon is to be incorporated into the surface of the phase shift layer, it is possible to employ a means for supplying a carbon-containing gas into the supply gas during the formation of the phase shift layer to the desired thickness, a means for supplying a carbon-containing material to the surface of the phase shift layer after the film formation, in particular, a means for modifying the surface of the phase shift layer with a carbon-containing gas, a means for modifying the surface of the phase shift layer by applying a carbon-containing material, or a means for modifying the phase shift layer by carbon-doping a carbon-containing material.

[0025] (6) The method for producing a phase shift mask blank of the present invention comprises the steps of: In the phase shift layer forming step, a partial pressure of a carbon-containing gas is set as a supply gas in sputtering to contain carbon in the surface of the phase shift layer, thereby forming the high-carbon region; It is possible.

[0026] According to the above configuration, the wettability of the surface of the phase shift layer can be improved, and the adhesion of the surface of the phase shift layer to the resist layer can be improved, thereby preventing a decrease in the accuracy of the pattern shape of the phase shift pattern due to the progress of etching caused by an etchant penetrating into the interface between the phase shift layer and the resist layer during wet etching to form a phase shift pattern. Moreover, by simply supplying a carbon-containing gas to the chamber in which the phase shift layer is formed, it is possible to easily form a high-carbon region while maintaining a vacuum and airtight condition, without having to take the transparent substrate in or out of the chamber.

[0027] (7) A phase shift mask according to another aspect of the present invention is a phase shift mask manufactured from a phase shift mask blank according to any one of (1) to (4) above, or manufactured by a method for manufacturing a phase shift mask blank according to (5) or (6) above, In the mask pattern, the phase shift pattern formed from the phase shift layer has an oxygen concentration of 70% or more throughout the entire region in the film thickness direction, and has a high carbon region with a carbon concentration of 3.5 atm% or more on a surface separated from the transparent substrate in the film thickness direction. It is possible.

[0028] According to the above configuration, the presence of a high-carbon region on the surface of the phase shift pattern improves the wettability of the surface of the phase shift pattern, thereby improving adhesion between the surface of the phase shift pattern and the resist pattern, thereby preventing etchant from penetrating the interface between the phase shift pattern and the resist pattern during wet etching to form the phase shift pattern, and preventing unnecessary etching at the interface. This makes it possible to form a phase shift mask that maintains high shape accuracy in the high-resolution phase shift pattern and the optical properties required for the phase shift pattern.

[0029] (8) The phase shift mask of the present invention is the one described above in (7), the high carbon region in the phase shift pattern has a thickness of 10 nm or less in a film thickness direction; It is possible.

[0030] According to the above-mentioned configuration, the wettability of the surface of the phase shift pattern is improved, and the adhesion of the surface of the phase shift pattern to the resist pattern is improved, so that during wet etching to form the phase shift pattern, an etchant is prevented from penetrating into the interface between the phase shift pattern and the resist pattern, and unnecessary etching at the interface does not proceed. As a result, a phase shift mask can be formed that maintains high shape accuracy in the high-resolution phase shift pattern and the optical properties required for the phase shift pattern. Furthermore, since the high carbon region has the above-mentioned thickness, the high carbon region remains even when subjected to etching or cleaning in a pattern formation process, etc., thereby maintaining the surface wetting properties and optical properties of the phase shift pattern and ensuring shape accuracy.

[0031] (9) The phase shift mask of the present invention is the one described above in (7) or (8), the water contact angle of the surface of the high carbon region in the phase shift pattern is 50 degrees or more; It is possible.

[0032] According to the above-mentioned configuration, the wettability of the surface of the phase shift pattern is improved, and the adhesion of the surface of the phase shift pattern to the resist pattern is improved, so that during wet etching to form the phase shift pattern, an etchant is prevented from penetrating into the interface between the phase shift pattern and the resist pattern, and unnecessary etching at the interface does not proceed. As a result, a phase shift mask can be formed that maintains high shape accuracy in the high-resolution phase shift pattern and the optical properties required for the phase shift pattern. In particular, for resists that require hydrophobicity to improve adhesion, such as Nagase ChemteX's GRX-M series resist materials, which are commonly used for metal etching in flat panel displays, the adhesion between the phase shift pattern and the resist pattern can be improved, making it possible to maintain high shape accuracy in high-resolution phase shift patterns.

[0033] (10) A phase shift mask according to the present invention is any one of the above (7) to (9), the phase shift pattern is located on the outermost surface of the mask pattern laminated on the transparent substrate; It is possible.

[0034] According to the above configuration, the wettability of the surface of the phase shift pattern located at the outermost surface of the mask pattern can be improved, and the adhesion of the surface of the phase shift pattern to the resist pattern can be improved while maintaining the optical properties of the phase shift pattern. That is, the adhesion of the surface of the mask pattern to the resist pattern can be improved. This makes it possible to prevent an etchant from penetrating the interface between the mask pattern and the resist pattern during wet etching to form the phase shift pattern, i.e., the mask pattern as a photomask, and causing the etching to progress, thereby preventing a decrease in the accuracy of the pattern shape of the mask pattern.

[0035] (11) Another aspect of the present invention provides a method for manufacturing a phase shift mask according to any one of (7) to (10) above, comprising the steps of: a resist pattern forming step of forming a resist pattern on the mask layer; a phase shift pattern forming step of forming a pattern in the phase shift layer; and In the phase shift pattern forming step, the high carbon region remains. It is possible.

[0036] According to the above-mentioned configuration, the wettability of the surface of the phase shift layer located at the outermost surface of the mask layer can be improved, and the adhesion of the surface of the phase shift layer to the resist pattern can be improved while maintaining the optical properties of the phase shift pattern. That is, the adhesion of the surface of the mask layer to the resist pattern can be improved. This makes it possible to prevent an etchant from penetrating the interface between the mask pattern and the resist pattern during wet etching to form the phase shift pattern, i.e., the mask pattern as a photomask, and thus to prevent the accuracy of the pattern shape of the mask pattern from decreasing as the etching progresses. [Effects of the Invention]

[0037] According to the present invention, it is possible to achieve the effect of improving the adhesion between the phase shift layer and the resist layer, thereby maintaining both the shape accuracy and the optical characteristics of the phase shift pattern. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a cross-sectional view showing a first embodiment of a phase shift mask blank according to the present invention. [Figure 2] 1 is a cross-sectional view showing a first embodiment of a method for producing a phase shift mask blank according to the present invention. [Figure 3] 1A to 1C are cross-sectional views showing the steps of a first embodiment of a method for manufacturing a phase shift mask according to the present invention. [Figure 4] 1A to 1C are cross-sectional views showing the steps of a first embodiment of a method for manufacturing a phase shift mask according to the present invention. [Figure 5] 1 is a cross-sectional view showing a first embodiment of a phase shift mask according to the present invention. [Figure 6] 1 is a flowchart showing manufacturing steps in a first embodiment of a method for manufacturing a phase shift mask blank and a phase shift mask according to the present invention. [Figure 7] 1 is a schematic diagram showing a film formation apparatus in a first embodiment of a method for producing a phase shift mask blank according to the present invention. [Figure 8] 1 is a schematic diagram showing a film formation apparatus in a first embodiment of a method for producing a phase shift mask blank according to the present invention. [Figure 9] 4 is a graph showing the carbon concentration in the depth direction in the phase shift layer in the first embodiment of the method for manufacturing a phase shift mask blank and a phase shift mask according to the present invention. [Figure 10] 4 is a graph showing the oxygen concentration in the depth direction in the phase shift layer in the phase shift mask blank and the first embodiment of the method for manufacturing a phase shift mask according to the present invention. [Figure 11]3 is a graph showing the chromium concentration in the depth direction in the phase shift layer in the phase shift mask blank and the first embodiment of the method for manufacturing a phase shift mask according to the present invention. [Figure 12] 4 is a graph showing the nitrogen concentration in the depth direction in the phase shift layer in the phase shift mask blank and the first embodiment of the method for manufacturing a phase shift mask according to the present invention. [Figure 13] 10 is an image showing the contact angle in a phase shift layer in an example of a phase shift mask blank and a method for manufacturing a phase shift mask according to the present invention. [Figure 14] 1 is an image showing the contact angle in a phase shift layer in a phase shift mask blank and a phase shift mask manufacturing method. [Figure 15] 10 is an image showing the penetration width in a phase shift pattern in an example of a phase shift mask blank and a method for manufacturing a phase shift mask according to the present invention. [Figure 16] 1 is an image showing the penetration width in a phase shift pattern in a phase shift mask blank and a phase shift mask manufacturing method. [Figure 17] 1 is a graph showing the relationship between the surface carbon concentration and the contact angle in the phase shift layer in an example of a method for manufacturing a phase shift mask blank and a phase shift mask according to the present invention. [Figure 18] 1 is a graph showing the relationship between the surface carbon concentration and the penetration width in the phase shift layer in an example of a method for manufacturing a phase shift mask blank and a phase shift mask according to the present invention. [Figure 19] 1 shows the relationship between the surface carbon concentration, contact angle, and penetration width in the phase shift layer in an example of a phase shift mask blank and a method for manufacturing a phase shift mask according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0039] A first embodiment of a phase shift mask blank, a phase shift mask, and a manufacturing method thereof according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a phase shift mask blank in this embodiment, and FIG. 2 is a cross-sectional view showing a phase shift mask blank in this embodiment, in which reference numeral 10B denotes a phase shift mask blank.

[0040] The phase shift mask blank 10B according to this embodiment is intended to be used as a phase shift mask (photomask) for use with exposure light having a wavelength in the range of approximately 300 nm to 312 nm to 365 nm to 436 nm. A phase shift mask blank 10B according to this embodiment is composed of a glass substrate (transparent substrate) 11 and a phase shift layer 12 formed on this glass substrate 11, as shown in FIG.

[0041] Furthermore, the phase shift mask blank 10B according to this embodiment can also be configured such that a photoresist layer 15 is formed in advance on a mask layer consisting of a single phase shift layer 12 as shown in FIG. 1, as shown in FIG. 2.

[0042] The phase shift mask blank 10B according to this embodiment may have a laminated structure including an anti-reflection layer, a chemical-resistant layer, a protective layer, an adhesion layer, an etching stop layer, a light-shielding layer, etc. in addition to the phase shift layer 12. Furthermore, a photoresist layer 15 may be formed on these laminated films, as shown in FIG.

[0043] A material having excellent transparency and optical isotropy, such as a quartz glass substrate, is used as the glass substrate (transparent substrate) 11. The size of the glass substrate 11 is not particularly limited and is appropriately selected depending on the substrate to be exposed using the mask (for example, a substrate for an FPD such as an LCD (liquid crystal display), a plasma display, or an OEL (organic electroluminescence) display).

[0044] In this embodiment, a rectangular substrate with a side length of approximately 100 mm to 3000 mm or more can be used as the glass substrate (transparent substrate) 11, and further, a substrate with a thickness of 1 mm or less, a substrate with a thickness of several mm, or a substrate with a thickness of 10 mm or more can also be used.

[0045] The surface of the glass substrate 11 may be polished to reduce the flatness of the glass substrate 11. The flatness of the glass substrate 11 can be, for example, 20 μm or less. This increases the depth of focus of the mask, which contributes greatly to the formation of fine and highly accurate patterns. Furthermore, the smaller the flatness, the better, as is 10 μm or less.

[0046] The phase shift layer 12 is made of a material containing Cr (chromium) as a main component, and further containing C (carbon), O (oxygen), and N (nitrogen). The phase shift layer 12 has a high carbon region 12c, which will be described later, on the surface on the side away from the glass substrate 11 in the thickness direction. The phase shift layer 12 may have a composition that varies in the thickness direction. In this case, the phase shift layer 12 may be formed by laminating one or more materials selected from Cr alone, and oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides of Cr. As will be described later, the thickness of the phase shift layer 12 and the composition ratio (atm %) of Cr, N, C, O, etc. are set so as to obtain predetermined optical characteristics and resistivity.

[0047] The thickness of the phase shift layer 12 is set depending on the optical properties required of the phase shift layer 12, and varies depending on the composition ratio of Cr, N, C, O, etc. The thickness of the phase shift layer 12 can be set to 50 nm to 150 nm.

[0048] For example, the composition ratios of the phase shift layer 12 can be set so that the carbon content (carbon concentration) is selected from the range of 0.5 atm% to 10.3 atm%, the oxygen content (oxygen concentration) is selected from the range of 70.0 atm% to 76.0 atm%, the nitrogen content (nitrogen concentration) is selected from the range of 1.8 atm% to 42.3 atm%, and the chromium content (chromium concentration) is selected from the range of 10.3 atm% to 42.4 atm%, and further, the composition ratios of Cr, N, C, O, etc. can be selected from each range so that the total of the composition ratios of these elements is 100 atm%. Therefore, in the phase shift layer 12, the composition ratios of Cr, N, C, O, etc. are appropriately selected from each of the above ranges so that the total of the composition ratios is 100 atm% in order to exhibit predetermined optical characteristics.

[0049] Specifically, the phase shift layer 12 may have a composition ratio of about 2 atm% carbon, 73 atm% oxygen, 22.5 atm% chromium, and 2 atm% nitrogen, etc. In this case, if the ratio is less than 100 atm%, it does not mean that the remainder contains other compositions, but simply indicates that there is a measurement error and an error in the summation of the measurements.

[0050] As a result, for example, when the phase shift layer 12 has a refractive index of about 2.4 to 3.1 and an extinction coefficient of 0.3 to 2.1 in a wavelength range of about 365 nm to 436 nm, the thickness can be set to about 90 nm. The composition ratio and film thickness of phase shift layer 12 are set depending on the optical characteristics required for phase shift mask 10 to be manufactured, and are not limited to the above values.

[0051] A high-carbon region 12c having a carbon concentration of about 3.5 atm% or more is formed on the surface of the phase shift layer 12. The high-carbon region 12c is formed over the entire surface of the phase shift layer 12 farthest from the glass substrate 11 in the thickness direction.

[0052] The composition ratio of the high carbon region 12c other than carbon is the same as that of the phase shift layer 12, including Cr, N, O, and the like. That is, high carbon region 12c may also be configured by laminating one or more materials selected from the group consisting of oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides of Cr. Furthermore, high carbon region 12c may have a composition that varies along its thickness.

[0053] As described below, the thickness and composition ratio (atm %) of Cr, N, C, and O of high-carbon region 12c are set so as to obtain predetermined adhesion (hydrophobicity) and predetermined optical characteristics. In high-carbon region 12c, increasing the carbon concentration in the chromium compound reduces hydrophilicity and improves hydrophobicity, making it possible to increase the water contact angle to 50 degrees or more. This allows for improved adhesion between high-carbon region 12c and photoresist layer 15.

[0054] The carbon concentration at the outermost surface of the high carbon region 12c is set to be about 1.5 to 2 times higher than the carbon concentration in the phase shift layer 12 that is closest to the glass substrate 11 in the thickness direction. Specifically, the average carbon concentration in the phase shift layer 12 is about 2% or 1 to 3 atm%, while the highest carbon concentration in the high carbon region 12c can be about 6 atm%, at least 5.5 atm%, or 5 atm% or more.

[0055] The thickness of high-carbon region 12c is set based on the conditions required for high-carbon region 12c, i.e., film properties such as adhesion (hydrophobicity) with photoresist layer 15 (described later) and the optical properties required for phase shift layer 12. These film properties of light-shielding layer 14 vary depending on the composition ratio of Cr, N, C, O, etc. The thickness of high-carbon region 12c can be set based on the optical properties required for phase shift mask 10.

[0056] The high carbon region 12c can be set to a thickness of 10 nm or less. Specifically, the high carbon region 12c can be set to a thickness of about 0.5 to 10 nm, preferably about 2 to 5 nm, 3 to 6 nm, 1 to 4 nm, 1 to 6 nm, 2 to 4 nm, or 3 to 5 nm.

[0057] Here, as will be described later, it is sufficient for high carbon region 12c to maintain predetermined surface wettability, water contact angle, and adhesion to resist layer 15, and therefore there is no need to limit the film thickness, etc., as long as the surface characteristics can be maintained. However, if high carbon region 12c is too thick, such as about 15 nm or more, it is not preferable because it may affect the optical properties of phase shift layer 12 and the optical properties as a mask layer.

[0058] The high carbon region 12c has a gradient carbon concentration such that the carbon concentration is highest at its outermost surface and gradually decreases as it approaches the glass substrate 11 in the thickness direction, until it becomes equivalent to the carbon concentration in the phase shift layer 12.

[0059] Here, the carbon concentration in high-carbon region 12c refers to the carbon concentration at the outermost surface, which is related to the surface characteristics. That is, as will be described later, even if the outermost surface of high-carbon region 12c is removed very shallowly with a small thickness by a process such as etching or cleaning in a phase-shift mask blank manufacturing process or a photomask manufacturing process, the carbon concentration at the surface of the remaining portion should be set to be within the above-mentioned predetermined range.

[0060] Therefore, if it is assumed in advance that the surface of the high carbon region 12c will be removed by the above-mentioned process, the carbon concentration, concentration gradient, and thickness of the high carbon region 12c can be set so as to maintain a predetermined carbon concentration.

[0061] By setting the film thickness and composition of the high carbon region 12c as described above, adhesion to the photoresist layer 15 used for etching a chromium-based film, for example, is improved during patterning by photolithography, and penetration of the etching solution at the interface with the photoresist layer 15 does not occur, resulting in a good pattern shape and enabling the formation of a desired pattern.

[0062] If high carbon region 12c is not set to the above conditions, the adhesion with photoresist layer 15 will not be in a predetermined state, causing photoresist layer 15 to peel off, allowing the etching solution to penetrate into the interface and making it impossible to form a pattern, which is undesirable. Also, if the film thickness of high carbon region 12c is not set to the above conditions, it will be difficult to set the optical properties of the mask layer as a photomask to the desired conditions, or the cross-sectional shape of the mask pattern may not be in the desired state, which is undesirable.

[0063] Here, it is possible to reduce hydrophilicity and improve hydrophobicity and adhesion by increasing the oxygen and nitrogen concentrations in the chromium compound in the high-carbon region 12c and the phase shift layer 12. At the same time, it is also possible to lower the refractive index and extinction coefficient by increasing the oxygen and nitrogen concentrations in the chromium compound, or to raise the refractive index and extinction coefficient by decreasing the oxygen and nitrogen concentrations in the chromium compound.

[0064] The method for manufacturing a phase shift mask blank in this embodiment includes a step of forming a phase shift layer 12 on a glass substrate (transparent substrate) 11 and a step of forming a high carbon region 12c, and the high carbon region 12c is formed simultaneously with or after the formation of the phase shift layer 12. If there are layers other than the high carbon region 12c and the phase shift layer 12, a step of depositing the corresponding layers may be included.

[0065] The method for manufacturing a phase shift mask blank and a phase shift mask according to this embodiment will be described below with reference to the drawings.

[0066] Fig. 3 is a cross-sectional view showing the manufacturing process of a phase shift mask blank and a phase shift mask according to this embodiment. Fig. 4 is a cross-sectional view showing the manufacturing process of a phase shift mask blank and a phase shift mask according to this embodiment. Fig. 5 is a cross-sectional view showing a phase shift mask according to this embodiment. Fig. 6 is a flowchart showing the manufacturing process of a phase shift mask blank and a phase shift mask according to this embodiment. As shown in FIG. 5, phase shift mask (photomask) 10 in this embodiment is formed by forming a pattern in phase shift layer 12, which is a mask layer stacked as phase shift mask blank 10B, and high carbon region 12c.

[0067] First, a method for manufacturing a phase shift mask blank 10B in this embodiment will be described with reference to the drawings. The phase shift mask blank 10B in this embodiment is manufactured by a manufacturing apparatus shown in FIG. FIG. 7 is a schematic diagram showing a manufacturing apparatus for a phase shift mask blank in this embodiment.

[0068] 7 is an inter-back sputtering apparatus that includes a load / unload chamber S11 and a film formation chamber (vacuum processing chamber, film formation unit) S12.

[0069] The load / unload chamber S11 is provided with a transfer mechanism S11a and an exhaust mechanism S11f. The transfer mechanism S11a transfers the glass substrate 11 carried in from the outside to the film formation chamber S12. The transfer mechanism S11a transfers the glass substrate 11 on which film formation has been completed from the film formation chamber S12 to the outside. The exhaust mechanism S11b is a rotary pump or the like that roughly evacuates the inside of the load / unload chamber S11. The loading / unloading chamber S11 is connected to the film forming chamber S12 via a sealing mechanism S17.

[0070] The film formation chamber S12 is provided with a film formation mechanism including a substrate holding mechanism S12a, a cathode electrode (backing plate) S12c having a target S12b, a power source S12d, a gas introduction mechanism S12e, and a high-vacuum evacuation mechanism S12f.

[0071] The substrate holding mechanism S12a receives the glass substrate 11 transported by the transport mechanism S11a, and holds the glass substrate 11 so as to face the target S12b during film formation. The substrate holding mechanism S12a is also capable of loading a glass substrate S from the load / unload chamber S11. The substrate holding mechanism S12a is also capable of unloading a glass substrate S into the load / unload chamber S11.

[0072] The target S12b is made of a material having a composition necessary for forming the phase shift layer 12 and the high carbon region 12c on the glass substrate 11, which will be described later. The power supply S12d applies a negative sputtering voltage to the cathode electrode (backing plate) S12c having the target S12b.

[0073] The gas introduction mechanism S12e supplies gas into the film formation chamber S12. The high vacuum pumping mechanism S12f is a turbo molecular pump or the like that draws a high vacuum inside the film formation chamber S12. The cathode electrode (backing plate) S12c, the power source S12d, the gas introduction mechanism S12e, and the high-vacuum exhaust mechanism S12f are configured to supply materials for forming the phase shift layer 12 and the high-carbon region 12c, respectively.

[0074] Specifically, in the film formation mechanism of the film formation chamber S12, the target S12b is made of a material containing chromium as a composition necessary for forming the phase shift layer 12 on the glass substrate 11.

[0075] At the same time, in the film formation mechanism of the film formation chamber S12, the gas supplied from the gas introduction mechanism S12e is set to a process gas containing carbon, nitrogen, oxygen, etc., corresponding to the formation of the phase shift layer 12, and is set to a predetermined gas partial pressure together with a sputtering gas such as argon or nitrogen gas. In addition, evacuation is performed from the high vacuum evacuation mechanism S12f according to the film formation conditions. In the film-forming mechanism S13, the sputtering voltage applied from the power supply S12d to the backing plate S12c is set in accordance with the formation of the phase shift layer 12.

[0076] 7, a phase shift layer 12 serving as a mask layer is first formed on a glass substrate 11 carried in from a load / unload chamber S11 in a deposition chamber (vacuum processing chamber) S12 by sputtering. Next, a high carbon region 12c is formed in the deposition chamber (vacuum processing chamber) S12 by sputtering. At this time, the deposition gas supplied to the deposition chamber (vacuum processing chamber) S12 is switched. Then, the glass substrate 11 on which the phase shift layer 12 and the high carbon region 12c are formed is carried out from the load / unload chamber S11 to the outside.

[0077] During film formation, sputtering gas and reactive gas are supplied to the film formation chamber S12 from the gas introduction mechanism S12e, and a sputtering voltage is applied to the backing plate (cathode electrode) S12c from an external power supply. A predetermined magnetic field may also be formed on the target S12b by a magnetron magnetic circuit. Ions of the sputtering gas excited by plasma in the film formation chamber S12 collide with the target S12b on the cathode electrode S12c, ejecting particles of the film formation material. The ejected particles then combine with the reactive gas and adhere to the glass substrate S, forming a predetermined film on the surface of the glass substrate S.

[0078] FIG. 8 is a schematic diagram showing a manufacturing apparatus for manufacturing a phase shift mask blank in this embodiment. 8 is an in-line sputtering apparatus that includes a load chamber S21, a film formation chamber (vacuum processing chamber, film formation unit) S22, and an unload chamber S23.

[0079] The load chamber S21 is provided with a transfer mechanism S21a and an exhaust mechanism S21b. The transfer mechanism S21a transfers the glass substrate 11 carried in from the outside to the film formation chamber S22. The exhaust mechanism S21b is a rotary pump or the like that roughly evacuates the inside of the load chamber S21. The load chamber S21 is connected to a film formation chamber (vacuum processing chamber) S22 via a sealing mechanism S27.

[0080] The film formation chamber S22 is provided with a substrate holding mechanism S22a, a cathode electrode (backing plate) S22c having a target S22b, a power source S22d, a gas introduction mechanism S22e, and a high-vacuum evacuation mechanism S22f.

[0081] The substrate holding mechanism S22a receives the glass substrate 11 transported by the transport mechanism S21a, and holds the glass substrate S so as to face the target S22b during film formation. The substrate holding mechanism S22a is also capable of loading the glass substrate 11 from the load chamber S21, and unloading the glass substrate 11 to the unload chamber S23.

[0082] The target S22b is made of a material having a composition necessary for forming the phase shift layer 12 and the high carbon region 12c on the glass substrate 11. The cathode electrode (backing plate) S22c, the power source S22d, the gas introduction mechanism S22e, and the high-vacuum exhaust mechanism S22f are configured to supply materials for forming the phase shift layer 12, the high-carbon region 12c, and the like.

[0083] The power supply S22d applies a negative sputtering voltage to the cathode electrode (backing plate) S22c having the target S22b. The gas introduction mechanism S22e introduces gas into the film formation chamber S22. The high vacuum pumping mechanism S22f is a turbo molecular pump or the like that draws a high vacuum inside the film formation chamber S22. The film forming chamber S22 is connected to the unloading chamber S23 via a sealing mechanism S28.

[0084] The unloading chamber S23 is provided with a transfer mechanism S23a and an exhaust mechanism S23b. The transfer mechanism S23a transfers the glass substrate 11 carried in from the film formation chamber S22 to the outside. The exhaust mechanism S23b is a rotary pump or the like that roughly evacuates the inside of the unload chamber S23.

[0085] 8, a phase shift layer 12 and a high-carbon region 12c are formed on a glass substrate 11 carried in from a load chamber S21 in a film-forming chamber (vacuum processing chamber) S22 by sputtering. At this time, the film-forming gas supplied to the film-forming chamber (vacuum processing chamber) S22 is switched. Thereafter, the glass substrate 11 on which film formation has been completed is carried out from an unload chamber S23 to the outside.

[0086] As shown in FIG. 6, the method for manufacturing the phase shift mask blank 10B in this embodiment includes a substrate preparation step S00, a phase shift layer formation step S01, a high carbon region formation step S02, a photoresist layer formation step S03, a resist pattern formation step S04, a phase shift pattern formation step S05, and a cleaning step S06.

[0087] Here, in describing the method for manufacturing phase shift mask blanks 10B in this embodiment, processing using the manufacturing apparatus S20 shown in Fig. 8 will be described. When manufacturing phase shift mask blanks MB using the manufacturing apparatus S10 shown in Fig. 7, the reference numerals in the S20s should be read as S10s, and the unload chamber S25 should be read as the load / unload chamber S11, etc.

[0088] 6, a glass substrate S is prepared after the above-described surface treatment etc. Thereafter, the glass substrate S is carried into a load chamber S21 shown in FIG. In the load chamber S21, the glass substrate 11 is supported by the transfer mechanism S21a, and after the load chamber S21 is sealed, the inside of the load chamber S21 is roughly evacuated to a vacuum by the exhaust mechanism S21b.

[0089] In this state, the sealing mechanism S27 is released, the glass substrate 11 is transported by the transport mechanism S21a, and the glass substrate 11 transported by the substrate holding mechanism S22a is received and carried into the film formation chamber (vacuum processing chamber) S22. In the film formation chamber S22, after the glass substrate 11 is carried in, the sealing mechanism S27 is sealed. In the film formation chamber (vacuum processing chamber) S22, the glass substrate 11 is held by a substrate holding mechanism S22a.

[0090] In the phase shift layer forming step S01 shown in Fig. 6, a high vacuum is evacuated to the inside of the film forming chamber (vacuum processing chamber) S22 shown in Fig. 8 by a high vacuum pumping mechanism S22f. Then, a sputtering gas and a reactive gas are supplied to the film forming chamber S22 by a gas introduction mechanism S22e, and a sputtering voltage is applied to a backing plate (cathode electrode) S22c from an external power supply. A predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

[0091] Ions of the sputtering gas excited by the plasma in the film formation chamber S22 collide with the target S22b of the cathode electrode S22c, causing particles of the film formation material to fly out. The particles then combine with the reactive gas and adhere to the glass substrate S, thereby forming a phase shift layer 12 on the surface of the glass substrate 11.

[0092] Here, the target S22b is replaced in advance with a target S22b having a composition required for forming the phase shift layer 12. A target made of chromium is proposed as the target S22b. Furthermore, as the deposition gas required for forming the phase shift layer 12, a gas containing oxygen, a gas containing carbon, a gas containing nitrogen, etc. are supplied at predetermined flow rates from a gas introduction mechanism S22e, and the partial pressures of the gases are controlled to set the composition within a set range. At this time, the phase shift layer 12 to be formed can have predetermined composition ratios of oxygen, carbon, nitrogen, and chromium in the thickness direction, as shown in FIGS. 9 to 12 described later.

[0093] When the phase shift layer 12 is formed with its composition varied in the film thickness direction, the partial pressure of each gas in the atmosphere gas can be varied depending on the film thickness. In particular, when forming the high-carbon region 12c, a carbon-containing gas is supplied and its partial pressure is controlled to keep the composition within a set range.

[0094] Here, examples of the oxygen-containing gas include CO2 (carbon dioxide), O2 (oxygen), N2O (nitrous oxide), NO (nitric oxide), and CO (carbon monoxide). Furthermore, examples of carbon-containing gases include CO2 (carbon dioxide), CH4 (methane), C2H6 (ethane), and CO (carbon monoxide). Furthermore, examples of nitrogen-containing gases include N2 (nitrogen gas), N2O (dinitrogen monoxide), NO (nitric oxide), N2O (dinitrogen monoxide), and NH3 (ammonia). If necessary, the target S22b can be replaced with a target material having a high carbon content, for example, in the deposition of the phase shift layer 12 and the high carbon region 12c.

[0095] In the high-carbon region forming step S02 shown in Fig. 6, the interior of the film formation chamber S22 shown in Fig. 8 is evacuated to a high vacuum by a high-vacuum exhaust mechanism S22f. Then, a sputtering gas and a reactive gas are supplied to the film formation chamber S22 from a gas introduction mechanism S22e, and a sputtering voltage is applied to a backing plate (cathode electrode) S22c from an external power supply. In addition, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

[0096] Ions of the sputtering gas excited by the plasma in the film formation chamber S22 collide with the target S22b of the cathode electrode S22c, causing particles of the film formation material to fly out. The particles then combine with the reactive gas and adhere to the glass substrate S, thereby forming a high-carbon region 12c on the surface of the glass substrate S (FIG. 1).

[0097] Here, the target S22b may be replaced in advance with a target S22b having a composition required for forming the high carbon region 12c. Alternatively, a predetermined flow rate of an oxygen-containing gas, a carbon-containing gas, a nitrogen-containing gas, or the like may be supplied from the gas introduction mechanism S22e as the film formation gas required for forming the high carbon region 12c, and the partial pressures of the gases may be controlled to set the composition within a set range.

[0098] Specifically, CO2 (carbon dioxide) is selected as the carbon-containing gas, and the partial pressure of this carbon-containing gas can be increased compared to that in the phase shift layer forming step S01. Alternatively, the gas flow rate of the carbon-containing gas can be increased compared to that in the phase shift layer forming step S01. At this time, the high carbon region 12c to be formed can have predetermined composition ratios of oxygen, carbon, nitrogen, and chromium in the thickness direction, as shown in FIGS. 9 to 12 described later.

[0099] Furthermore, if other films are to be stacked in addition to the formation of the phase shift layer 12 and the high carbon region 12c, the films are formed by sputtering using the corresponding sputtering conditions such as target and gas, or the relevant films are stacked by other film formation methods to form the phase shift mask blank 10B of this embodiment.

[0100] In the photoresist layer forming step S03 shown in Figure 6, a photoresist layer 15 is formed on the high carbon region 12c, which is the uppermost layer in the high carbon region forming step S02 (Figure 2). The photoresist layer 15 may be either positive or negative, but is preferably positive. As the photoresist layer 15, a liquid resist, an adhesive film, or the like is used.

[0101] The photoresist layer (resist layer) 15 can be made of a resist material such as the GRX-M series from Nagase ChemteX Corporation, which is generally used for metal etching in flat displays.

[0102] In resist pattern forming step S04 shown in FIG. 6, photoresist layer 15 is exposed and developed to form photoresist pattern 15P1 having a predetermined pattern shape (opening pattern) on high carbon region 12c (FIG. 3). Photoresist pattern 15P1 functions as an etching mask for high carbon region 12c and phase shift layer 12, and its shape is determined appropriately according to the etching patterns of high carbon region 12c and phase shift layer 12.

[0103] Next, in a phase shift pattern forming step S05 shown in FIG. 6, high carbon region 12c and phase shift layer 12 are sequentially wet-etched using a predetermined etching solution through photoresist pattern 15P1. At this time, in etching the chromium-containing high carbon region 12c and the phase shift layer 12, an etching solution containing a chromium etchant, for example, cerium diammonium nitrate, can be used. As a result, a high carbon region pattern 12cP1 and a phase shift pattern 12p1 are formed (FIG. 4).

[0104] Next, in a cleaning step S06 shown in FIG. 6, the photoresist pattern 15P1 is removed using a predetermined cleaning liquid. As the cleaning liquid, sulfuric acid / hydrogen peroxide mixture or ozone water can be used.

[0105] This allows for the production of a phase shift mask (photomask) 10 in which a predetermined optically set high carbon region pattern 12cP1 and a phase shift pattern 12P1 are formed, each having a phase shift region and a transmission region with the desired optical characteristics, as shown in Figure 5.

[0106] According to phase shift mask 10 of the present embodiment, phase shift mask blank 10B has a single phase shift layer 12 laminated as a mask layer, which is an optical layer, and by forming extremely thin high-carbon region 12c on the surface of phase shift layer 12, the wettability of the surface of phase shift layer 12 is improved, thereby improving adhesion to photoresist layer 15, and preventing penetration of the etching solution at the interface between phase shift layer 12 and photoresist layer 15 in phase shift pattern formation step S05, thereby preventing etching from progressing at the interface between phase shift layer 12 and photoresist layer 15. This prevents the sidewalls of the pattern edges of phase shift pattern 12P1, i.e., the side surfaces perpendicular to the surface of glass substrate 11, from being gouged out below photoresist pattern 15P1 from the originally intended vertical pattern shape, thereby preventing a decrease in the pattern shape accuracy of the phase shift pattern.

[0107] A second embodiment of the phase shift mask blank and phase shift mask according to the present invention will be described below. This embodiment differs from the first embodiment described above in terms of the method for forming the high carbon region, and a description of other configurations that correspond to those of the first embodiment described above will be omitted.

[0108] The high-carbon region 12c according to this embodiment is formed by performing plasma treatment in a carbon-containing gas atmosphere on the surface of the phase shift layer 12 after the phase shift layer 12 is formed. Here, carbon can be incorporated by forming plasma in the carbon-containing gas atmosphere and exposing the surface of the phase shift layer 12 to the plasma under predetermined conditions for a predetermined time. Here, as in the first embodiment, gases such as methane, carbon dioxide, and carbon monoxide can be used as the carbon-containing gas.

[0109] In this embodiment, it is possible to achieve the effect of stably transforming only the surface layer of the phase shift mask into a desired state.

[0110] A third embodiment of the phase shift mask blank and phase shift mask according to the present invention will now be described. This embodiment differs from the first embodiment described above in terms of the method for forming the high carbon region, and a description of other configurations that correspond to those of the first embodiment described above will be omitted.

[0111] The high-carbon region 12c according to this embodiment is formed by coating the surface of the phase shift layer 12 with a carbon-containing material and then performing plasma treatment in that state after the phase shift layer 12 is formed. Here, carbon can be incorporated by coating the surface of the phase shift layer 12 with an organic compound such as hexamethyldisiloxane as the carbon-containing material, placing the phase shift layer 12 in a plasma treatment space, and exposing the surface of the phase shift layer 12 to the plasma under predetermined conditions for a predetermined time.

[0112] In this embodiment, it is possible to easily change the outermost surface layer of a phase shift mask into a desired state without using a vacuum device. [Example]

[0113] Hereinafter, examples of the present invention will be described. Here, confirmation tests for the phase shift layer 12 and the high carbon region 12c of the present invention will be described as specific examples.

[0114] <Experimental Example 1> In Experimental Example 1, a chromium compound film was formed as a phase shift layer on a glass substrate using a sputtering method or the like. The chromium compound film formed here contained chromium, oxygen, nitrogen, carbon, etc. As a phase shift layer, a high-carbon region was formed on the outermost surface. The high-carbon region was formed by forming an extremely thin film with a different composition concentration and an increased carbon concentration on the outermost surface.

[0115] The parameters for forming the phase shift layer are shown below. Carbon-containing gases; CO2 (carbon dioxide) Target; Chrome The specifications for the high carbon region are shown below. Carbon-containing gases: CH4 (methane) and argon mixtures Target; Chrome As for gas supply changes during film formation, the target gas flow ratio is almost constant. Only carbon-containing gas is added and the flow ratio is increased according to the film thickness in the high carbon region.

[0116] <Composition evaluation> The composition of this film was evaluated by Auger electron spectroscopy. The results are shown in Figures 9 to 12. In Figures 9 to 12, the horizontal axis represents the depth direction distance (time), and the vertical axis represents the composition ratio (%) of each measurement target. 9 to 12, in Experimental Example 1, the composition ratios of Cr, O, and N are all almost constant in the film thickness direction (horizontal axis), whereas it was confirmed that a high-carbon region with a high carbon concentration was formed on the outermost surface of C shown in Fig. 9, which is the left side of the figure. In Fig. 9, the right end position of the high-carbon region is indicated by an arrow.

[0117] <Experimental Example 2> In Experimental Example 2, a film of a chromium compound was formed as a phase shift layer by sputtering or the like, similarly to Experimental Example 1. In Experimental Example 2, no high carbon region was formed.

[0118] The composition of this film was evaluated by Auger electron spectroscopy. The results are shown in FIGS. As shown in FIGS. 9 to 12, the composition ratio of Cr, O, N, and C in Experimental Example 2 can be considered to be approximately the same as that of the phase shift layer in Experimental Example 1.

[0119] <Contact angle measurement> Next, in order to check the wettability of the surfaces of the above Experimental Examples 1 and 2, the contact angle of water on the surface was measured. Here, pure water was dropped on the surface of the formed film, and the contact angle was measured visually. Specifically, the contact angle was measured from a photographed image. The results are shown in Figures 13 and 14. As shown in FIGS. 13 and 14, in Experimental Example 1 where the surface carbon concentration was high, the water contact angle was 58 degrees, and in Experimental Example 2 where the surface carbon concentration was low, the water contact angle was 26 degrees.

[0120] <Penetration width measurement> Next, in Experimental Example 4, in order to confirm the adhesion of the photoresist layer to the surface of Experimental Examples 1 and 2, a resist pattern was formed, and then etching was carried out, and the penetration width due to penetration of the etching solution was measured.

[0121] The patterning specifications are shown below. Resist; Resist type GRX-M237 Film thickness: 735 nm Pre-bake 87℃ 48min Exposure: Contact exposure machine (Tamarack) Development: DIP type Developer AZ DEVELOPER (50% diluted with pure water) Development time: 0 seconds longer than specified Etching: Paddle type Etching solution: MPM-E Etching time: 0 seconds longer than specified

[0122] The cross sections of the patterned phase shift pattern and resist pattern were observed. The SEM images are shown in Figures 15 and 16. In each figure, the phase shift layer is shown as Cr-PSM. As shown in Figures 15 and 16, in Experimental Example 2, penetration occurred, causing the interface to be gouged out by about 150 nm, whereas in Experimental Example 1, no penetration occurred, and it can be seen that the phase shift layer and the resist layer were in close contact at the interface.

[0123] <Experimental Example 3> In Experimental Example 3, a chromium compound film was formed as a phase shift layer by sputtering or the like, similarly to Experimental Examples 1 and 2. In Experimental Example 3, the carbon concentration was set to 3.1%, and no high-carbon region was formed. Similarly, the contact angle and penetration width of water were measured. The results are shown in FIGS. 17 to 19.

[0124] <Experimental Example 4> In Experimental Example 4, a chromium compound film was formed as a phase shift layer by sputtering or the like, similarly to Experimental Examples 1 to 3. In Experimental Example 3, the carbon concentration was set to 3.9% to form a high-carbon region. Similarly, the contact angle and penetration width of water were measured. The results are shown in FIGS. 17 to 19.

[0125] <Experimental Example 5> In Experimental Example 5, a chromium compound film was formed as a phase shift layer by sputtering or the like, similarly to Experimental Examples 1 to 4. In Experimental Example 3, the carbon concentration was set to 5.2% to form a high carbon region. Similarly, the contact angle and penetration width of water were measured. The results are shown in FIGS. 17 to 19.

[0126] These results show that the surface wettability, water contact angle, adhesion to the resist layer, and penetration width change depending on the surface carbon concentration. Furthermore, it is clear that the accuracy of the shape during pattern formation can be ensured by forming a high-carbon region or by forming a resist and etching it while leaving the high-carbon region. [Industrial Applicability]

[0127] An example of the application of the present invention is miniaturization of masks for flat panel displays. [Explanation of symbols]

[0128] 10...Phase shift mask 10B...Phase shift mask blanks 11...Glass substrate (transparent substrate) 12...Phase shift layer 12c...High carbon region 12P1...Phase shift pattern 15...Photoresist layer 15P1...Resist pattern

Claims

1. A phase shift mask blank having a mask layer that serves as a phase shift mask, a phase shift layer containing chromium, oxygen, and carbon deposited on a transparent substrate; the phase shift layer has an oxygen concentration of 70% or more throughout the entire thickness direction; the phase shift layer has a high carbon region having a carbon concentration of 3.5 atm % or more on a surface thereof separated from the transparent substrate in a thickness direction thereof; A phase shift mask blank characterized by:

2. the high-carbon region in the phase shift layer has a thickness of 10 nm or less in a film thickness direction; 2. The phase shift mask blank according to claim 1.

3. the contact angle of water on the surface of the high carbon region in the phase shift layer is 50 degrees or more; 3. The phase shift mask blank according to claim 1 or 2.

4. the phase shift layer is located on the outermost surface of the mask layer laminated on the transparent substrate; 4. The phase shift mask blank according to claim 1.

5. A method for producing a phase shift mask blank according to any one of claims 1 to 4, comprising the steps of: a phase shift layer forming step of laminating the phase shift layer containing chromium and oxygen on the transparent substrate, In the phase shift layer forming step, the high carbon region is formed by incorporating carbon into the surface of the phase shift layer to be laminated.

1. A method for producing a phase shift mask blank, comprising:

6. In the phase shift layer forming step, a partial pressure of a carbon-containing gas is set as a supply gas in sputtering to contain carbon in the surface of the phase shift layer, thereby forming the high-carbon region; 6. The method for producing a phase shift mask blank according to claim 5.

7. A phase shift mask manufactured from the phase shift mask blank according to any one of claims 1 to 4 or by the method for manufacturing a phase shift mask blank according to claim 5 or 6, In the mask pattern, the phase shift pattern formed from the phase shift layer has an oxygen concentration of 70% or more throughout the entire region in the film thickness direction, and has a high carbon region with a carbon concentration of 3.5 atomic % or more on a surface separated from the transparent substrate in the film thickness direction. A phase shift mask characterized by:

8. the high carbon region in the phase shift pattern has a thickness of 10 nm or less in a film thickness direction; 8. The phase shift mask according to claim 7.

9. the water contact angle of the surface of the high carbon region in the phase shift pattern is 50 degrees or more; 9. The phase shift mask according to claim 7, wherein the first and second electrodes are formed on the first and second substrates.

10. the phase shift pattern is located on the outermost surface of the mask pattern laminated on the transparent substrate; 10. The phase shift mask according to claim 7, wherein the first and second electrodes are formed on the first and second substrates.

11. 11. A method for manufacturing a phase shift mask according to claim 7, comprising the steps of: a resist pattern forming step of forming a resist pattern on the mask layer; a phase shift pattern forming step of forming a pattern in the phase shift layer; and In the phase shift pattern forming step, the high carbon region remains.

10. A method for manufacturing a phase shift mask, comprising:

Images