JP2023099947A - Phase shift mask blank, phase shift mask, production method - Google Patents

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

The present invention relates to techniques suitable for use in phase shift mask blanks, phase shift masks, and manufacturing methods.

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, mask blanks in which a mask layer is formed on a quartz substrate using a chromium compound may be used as the mask layer.

Here, it is common to use WET etching for patterning large masks used for FPDs and the like. In such a wet etching process, after laminating a resist layer on a mask layer made of a chromium-based material and patterning the resist layer, etching is performed by immersing or spraying a chromium etchant to form a patterned mask. forming a mask layer.
As a result, a photomask is manufactured in which the light-transmitting region in which the exposed pattern of the transparent substrate is not arranged and the light-shielding region in which the light-shielding layer is laminated on the transparent substrate are arranged adjacent to each other. (Patent document 1).

In recent years, there has been a great progress toward higher definition, and along with this, the miniaturization of photomasks has also progressed. Therefore, there is an increasing need for edge-enhanced phase shift masks as well as conventional masks using light-shielding films.
Conventionally, a phase shift mask is required to have a high contrast during exposure. Therefore, a phase shift layer is formed of a chromium compound as a mask layer on a quartz substrate, and a light shielding layer (binary A rim type phase shift mask with a layer) formed thereon may be used.
At this time, it is known to use a silicide film such as a molybdenum silicide film as an etching stop film used in WET etching (Patent Document 2).

JP 2019-008114 A WO2013/190786

Recently, however, unlike semiconductor device manufacturing, in FPD manufacturing, a phase shift mask in which a chromium-based phase shift layer called Cr-PSM is laminated as a single layer on a glass substrate is used as a phase shift mask. may form fine patterns. This is because, in recent years, the display of smartphones and the like has become increasingly high-definition, and along with this, the formation of fine patterns in display masks is required. The reason is that fine patterns can be formed by relatively simply using the phase shift effect.

As described above, in phase shift mask blanks having a chromium-based mask layer, if the adhesion between the resist layer and the chromium-based mask layer is insufficient, the etchant penetrates between the resist layer and the chromium-based mask layer. As a result, the shape of the formed mask pattern deteriorates. In particular, when the mask layer is formed as a chromium-based single layer, there has been a strong demand to improve this.

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

The inventors of the present application considered the following reasons why the adhesion between the phase shift layer and the resist layer is lowered, the etchant permeates, and the patterned shape is destroyed.

A phase-shifting layer made of a chromium compound has a very high oxygen content in order to have the necessary phase-shifting power and other optical properties. Therefore, the oxygen concentration at the surface that needs to adhere to the resist layer is similarly high. For this reason, the phase shift layer made of a chromium compound has a surface with high hydrophilicity, and the adhesion to the resist layer is lowered.

Therefore, in the wet etching process, the etchant penetrates between the chromium-based mask layer and the resist layer, and etching progresses in the vicinity of this interface to remove unnecessary portions. As a result, along the edge of the resist pattern, on the side surface extending in the film thickness direction of the mask layer expected to be formed perpendicular to the glass substrate surface, the mask layer is etched under the resist pattern. A sloped portion is formed. In other words, a phenomenon occurs in which the accuracy of the pattern shape in the phase shift pattern is lowered corresponding to the notch portion.

Therefore, in order to maintain the shape accuracy of the phase shift pattern, it is necessary to improve the adhesion between the phase shift layer and the resist layer. In order to realize this, it was considered effective to improve the hydrophobicity of the surface of the phase shift layer, that is, to increase the contact angle of water on the surface of the phase shift layer. At the same time, it is important to keep the phase-shifting ability and optical properties of the entire phase-shifting layer unchanged.
Taking these points into consideration, the inventors of the present application completed the present invention as follows.

(1) A phase shift mask blank according to one aspect of the present invention is
A phase shift mask blank having a mask layer serving as a phase shift mask,
having a phase shift layer laminated on a transparent substrate and containing chromium, oxygen and carbon;
The phase shift layer has an oxygen concentration of 70% or more in 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 separated from the transparent substrate in the film thickness direction.
Thus, the above problem was solved.
(2) In the phase shift mask blanks of the present invention, in (1) above,
The high carbon region in the phase shift layer is 10 nm or less in the film thickness direction,
be able to.
(3) The phase shift mask blank of the present invention is 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.
be able to.
(4) The phase shift mask blanks of the present invention, in any one of (1) to (3) above,
wherein the phase shift layer is positioned on the outermost surface of the mask layer laminated on the transparent substrate;
be able to.
(5) A method for manufacturing a phase shift mask blank according to another aspect of the present invention is the method for manufacturing a phase shift mask blank according to any one of (1) to (4) above,
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, carbon is contained in the surface of the phase shift layer to be laminated to form the high carbon region.
be able to.
(6) The method for manufacturing a phase shift mask blank of the present invention is the above (5),
In the phase shift layer forming step,
forming the high-carbon region by setting the partial pressure of a carbon-containing gas as a supply gas in sputtering to contain carbon in the surface of the phase shift layer;
be able to.
(7) A phase shift mask according to another aspect of the present invention is manufactured from the phase shift mask blanks described in any one of (1) to (4) above, or the phase shift mask blanks described in (5) or (6) above A phase shift mask manufactured by the phase shift mask blank manufacturing method of
In the mask pattern, the phase shift pattern formed from the phase shift layer has an oxygen concentration of 70% or more in the entire film thickness direction, and a surface separated from the transparent substrate in the film thickness direction has a carbon concentration. Having a high carbon region of 3.5 atm% or more,
be able to.
(8) The phase shift mask of the present invention is the above (7),
The high carbon region in the phase shift pattern is 10 nm or less in the film thickness direction,
be able to.
(9) The phase shift mask of the present invention is the above (7) or (8),
The contact angle of water on the surface of the high carbon region in the phase shift pattern is 50 degrees or more.
be able to.
(10) The phase shift mask of the present invention, in any one of (7) to (9) above,
wherein the phase shift pattern is positioned on the outermost surface of the mask pattern laminated on the transparent substrate;
be able to.
(11) A method of manufacturing a phase shift mask according to another aspect of the present invention is the method of manufacturing a phase shift mask according to any one of (7) to (10) above,
a resist pattern forming step of forming a resist pattern on the mask layer;
A phase shift pattern forming step of forming a pattern on the phase shift layer;
has
In the phase shift pattern forming step, the high carbon region remains,
be able to.

(1) A phase shift mask blank according to one aspect of the present invention is
A phase shift mask blank having a mask layer serving as a phase shift mask,
having a phase shift layer laminated on a transparent substrate and containing chromium, oxygen and carbon;
The phase shift layer has an oxygen concentration of 70% or more in 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 separated from the transparent substrate in the film thickness direction.
Thus, the above problem was solved.

According to the above configuration, by having the high carbon region on the surface of the phase shift layer, the wettability on the surface of the phase shift layer is improved while maintaining the optical properties of the phase shift layer. It is possible to improve the adhesion with the resist layer in. As a result, the etchant penetrates into the interface between the phase shift layer and the resist layer during wet etching for forming the phase shift pattern, and as the etching progresses, the pattern shape accuracy of the phase shift pattern decreases. can be prevented.

(2) In the phase shift mask blanks of the present invention, in (1) above,
The high carbon region in the phase shift layer is 10 nm or less in the film thickness direction,
be able to.

According to the above configuration, it is possible to improve wettability on the surface of the phase shift layer and improve adhesion between the surface of the phase shift layer and the resist layer while maintaining the optical properties of the phase shift layer. As a result, the etchant penetrates into the interface between the phase shift layer and the resist layer during wet etching for forming the phase shift pattern, and as the etching progresses, the pattern shape accuracy of the phase shift pattern decreases. can be prevented.
Furthermore, since the high-carbon region has the above thickness, the high-carbon region remains without disappearing even after etching or washing in the pattern formation process, etc., and the characteristics of the phase shift layer or the phase shift pattern surface are maintained. can do.

(3) The phase shift mask blank of the present invention is 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.
be able to.

According to the above configuration, it is possible to improve wettability on the surface of the phase shift layer and improve adhesion between the surface of the phase shift layer and the resist layer while maintaining the optical properties of the phase shift layer. As a result, the etchant penetrates into the interface between the phase shift layer and the resist layer during wet etching for forming the phase shift pattern, and as the etching progresses, the pattern shape accuracy of the phase shift pattern decreases. can be prevented.
In particular, for resists that require hydrophobicity in order to improve adhesion, such as Nagase ChemteX's GRX-M series resist materials, which are commonly used for metal etching for flat displays. Therefore, it is possible to improve the adhesion between the phase shift layer and the resist layer.

(4) The phase shift mask blanks of the present invention, in any one of (1) to (3) above,
wherein the phase shift layer is positioned on the outermost surface of the mask layer laminated on the transparent substrate;
be able to.

According to the above configuration, the wettability on the surface of the phase shift layer located on the outermost surface of the mask layer is improved, and the optical properties of the phase shift layer are maintained while the phase shift layer surface adheres to the resist layer. can improve sexuality. That is, the adhesion of the surface of the mask layer to the resist layer can be improved. As a result, during wet etching for forming a phase shift pattern, that is, a mask pattern as a photomask, the etchant enters the interface between the mask layer and the resist layer, and as the etching progresses, the pattern shape of the mask pattern changes. It is possible to prevent a decrease in accuracy.

(5) A method for manufacturing a phase shift mask blank according to another aspect of the present invention is the method for manufacturing a phase shift mask blank according to any one of (1) to (4) above,
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, carbon is contained in the surface of the phase shift layer to be laminated to form the high carbon region.
be able to.

According to the above configuration, the high-carbon region can be formed only by adding carbon to the surface of the phase shift layer in the conventional phase shift layer forming process. This makes it possible to improve wettability on the surface of the phase shift layer and improve adhesion between the surface of the phase shift layer and the resist layer while maintaining the optical properties of the phase shift layer. As a result, the etchant penetrates into the interface between the phase shift layer and the resist layer during wet etching for forming the phase shift pattern, and as the etching progresses, the pattern shape accuracy of the phase shift pattern decreases. It is possible to manufacture phase shift mask blanks without any problems.

Here, when carbon is contained in the surface of the phase shift layer, means for supplying a carbon-containing gas into the supply gas during film formation of the phase shift layer having the corresponding thickness, or a phase shift layer after film formation. Means for supplying a carbon-containing material to the surface of the layer, particularly means for modifying the surface of the phase shift layer with a carbon-containing gas, or means for modifying the surface of the phase shift layer by applying a carbon-containing material, carbon It is possible to adopt a means of modifying the phase shift layer by carbon doping of the containing material, or the like.

(6) The method for manufacturing a phase shift mask blank of the present invention is the above (5),
In the phase shift layer forming step,
forming the high-carbon region by setting the partial pressure of a carbon-containing gas as a supply gas in sputtering to contain carbon in the surface of the phase shift layer;
be able to.

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. As a result, the etchant penetrates into the interface between the phase shift layer and the resist layer during wet etching for forming the phase shift pattern, and as the etching progresses, the pattern shape accuracy of the phase shift pattern decreases. can be prevented.
Moreover, by simply supplying a carbon-containing gas to the chamber in which the phase shift layer is formed, the high-carbon region can be easily formed while maintaining vacuum and airtightness without taking the transparent substrate in and out of the chamber. It becomes possible.

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

According to the above configuration, by having the high-carbon region on the surface of the phase shift pattern, the wettability on the surface of the phase shift pattern is improved, and the adhesion between the surface of the phase shift pattern and the resist pattern is improved. , during wet etching for forming the phase shift pattern, the etchant is prevented from entering the interface between the phase shift pattern and the resist pattern, and unnecessary etching at the interface does not progress. This makes it possible to form a phase shift mask that maintains high shape accuracy in a high-definition phase shift pattern and optical characteristics required for the phase shift pattern.

(8) The phase shift mask of the present invention is the above (7),
The high carbon region in the phase shift pattern is 10 nm or less in the film thickness direction,
be able to.

According to the above configuration, the wettability of the surface of the phase shift pattern is improved, the adhesion of the surface of the phase shift pattern to the resist pattern is improved, and the phase shift pattern is formed during wet etching for forming the phase shift pattern. The etchant is prevented from entering the interface with the resist pattern, and unnecessary etching at the interface does not proceed. This makes it possible to form a phase shift mask that maintains high shape accuracy in a high-definition phase shift pattern and optical characteristics required for the phase shift pattern.
Furthermore, since the high-carbon region has the above thickness, the high-carbon region remains without disappearing even after etching or cleaning in the pattern formation process, etc., and the surface wettability and optical characteristics in the phase shift pattern are improved. can be maintained to ensure shape accuracy.

(9) The phase shift mask of the present invention is the above (7) or (8),
The contact angle of water on the surface of the high carbon region in the phase shift pattern is 50 degrees or more.
be able to.

According to the above configuration, the wettability of the surface of the phase shift pattern is improved, the adhesion of the surface of the phase shift pattern to the resist pattern is improved, and the phase shift pattern is formed during wet etching for forming the phase shift pattern. The etchant is prevented from entering the interface with the resist pattern, and unnecessary etching at the interface does not proceed. This makes it possible to form a phase shift mask that maintains high shape accuracy in a high-definition phase shift pattern and optical characteristics required for the phase shift pattern.
In particular, for resists that require hydrophobicity in order to improve adhesion, such as Nagase ChemteX's GRX-M series resist materials, which are commonly used for metal etching for flat displays. As a result, it is possible to improve the adhesion between the phase shift pattern and the resist pattern, and maintain high shape accuracy in the high-definition phase shift pattern.

(10) The phase shift mask of the present invention, in any one of (7) to (9) above,
wherein the phase shift pattern is positioned on the outermost surface of the mask pattern laminated on the transparent substrate;
be able to.

According to the above configuration, the wettability of the surface of the phase shift pattern located on the outermost surface of the mask pattern is improved, and the phase shift pattern adheres to the resist pattern on the surface while maintaining the optical characteristics of the phase shift pattern. can improve sexuality. That is, the adhesion between the surface of the mask pattern and the resist pattern can be improved. As a result, during wet etching for forming a phase shift pattern, that is, a mask pattern as a photomask, an etchant enters the interface between the mask pattern and the resist pattern. It is possible to prevent a decrease in accuracy.

(11) A method of manufacturing a phase shift mask according to another aspect of the present invention is the method of manufacturing a phase shift mask according to any one of (7) to (10) above,
a resist pattern forming step of forming a resist pattern on the mask layer;
A phase shift pattern forming step of forming a pattern on the phase shift layer;
has
In the phase shift pattern forming step, the high carbon region remains,
be able to.

According to the above configuration, the wettability of the surface of the phase shift layer located on the outermost surface of the mask layer is improved, and the adhesion of the phase shift layer to the resist pattern is maintained while maintaining the optical characteristics of the phase shift pattern. can improve sexuality. That is, it is possible to improve the adhesion between the surface of the mask layer and the resist pattern. As a result, during wet etching for forming a phase shift pattern, that is, a mask pattern as a photomask, an etchant enters the interface between the mask pattern and the resist pattern. It is possible to prevent a decrease in accuracy.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to improve the adhesiveness of a phase shift layer and a resist layer, and to produce the effect that the shape accuracy and optical characteristic in a phase shift pattern can be maintained simultaneously. .

1 is a cross-sectional view showing a first embodiment of a phase shift mask blank according to the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows 1st Embodiment of the manufacturing method of the phase shift mask blanks based on this invention. It is process sectional drawing which shows 1st Embodiment of the manufacturing method of the phase shift mask which concerns on this invention. It is process sectional drawing which shows 1st Embodiment of the manufacturing method of the phase shift mask which concerns on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows 1st Embodiment of the phase shift mask which concerns on this invention. 1 is a flow chart showing manufacturing steps in a first embodiment of a method for manufacturing phase shift mask blanks and a phase shift mask according to the present invention. 1 is a schematic diagram showing a film forming apparatus in a first embodiment of a method for manufacturing phase shift mask blanks according to the present invention; FIG. 1 is a schematic diagram showing a film forming apparatus in a first embodiment of a method for manufacturing phase shift mask blanks according to the present invention; FIG. 4 is a graph showing the carbon concentration in the depth direction in the phase shift layer in the first embodiment of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 5 is a graph showing the oxygen concentration in the depth direction in the phase shift layer in the first embodiment of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 5 is a graph showing the chromium concentration in the depth direction in the phase shift layer in the first embodiment of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 4 is a graph showing the nitrogen concentration in the depth direction in the phase shift layer in the first embodiment of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 4 is an image showing the contact angle in the phase shift layer in the example of the phase shift mask blanks and the method for manufacturing the phase shift mask according to the present invention. 4 is an image showing a contact angle in a phase shift layer in a method for manufacturing a phase shift mask blank and a phase shift mask. 4 is an image showing the penetration width in the phase shift pattern in the embodiment of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 4 is an image showing a penetration width in a phase shift pattern in a method of manufacturing a phase shift mask blank and a phase shift mask. 4 is a graph showing the relationship between the surface carbon concentration and the contact angle in the phase shift layer in the examples of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 5 is a graph showing the relationship between the surface carbon concentration and the penetration width in the phase shift layer in the example of the phase shift mask blanks and the phase shift mask manufacturing method according to the present invention. 1 shows the relationship between surface carbon concentration, contact angle, and penetration width 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.

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of phase shift mask blanks, a phase shift mask, and a manufacturing method according to the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing the phase shift mask blanks according to this embodiment, and FIG. 2 is a cross-sectional view showing the phase shift mask blanks according to this embodiment. be.

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

Furthermore, in the phase shift mask blank 10B according to the present embodiment, as shown in FIG. 1, a photoresist layer 15 is formed in advance as shown in FIG. A membrane configuration is also possible.

In addition to the phase shift layer 12, the phase shift mask blank 10B according to the present embodiment may have a structure in which an antireflection layer, a chemical resistant layer, a protective layer, an adhesion layer, an etching stop layer, a light shielding layer, etc. are laminated. . Furthermore, a photoresist layer 15 may be formed on these laminated films as shown in FIG.

As the glass substrate (transparent substrate) 11, a material having excellent transparency and optical isotropy is used, and for example, a quartz glass substrate can be used. The size of the glass substrate 11 is not particularly limited, and is appropriately selected according to the substrate to be exposed using the mask (for example, a substrate for FPD such as LCD (liquid crystal display), plasma display, OEL (organic electroluminescence) display, etc.). be done.

In this embodiment, as the glass substrate (transparent substrate) 11, a rectangular substrate having a side of about 100 mm to 3000 mm or more can be applied. Substrates can also be used.

Further, the flatness of the glass substrate 11 may be reduced by polishing the surface of the glass substrate 11 . The flatness of the glass substrate 11 can be set to 20 μm or less, for example. As a result, the depth of focus of the mask is increased, making it possible to greatly contribute to fine and highly accurate pattern formation. Furthermore, the flatness is 10 μm or less, and the smaller the better.

The phase shift layer 12 is mainly composed of Cr (chromium) and further contains 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 can also have different compositions in the thickness direction. One or two or more selected from nitrides may be laminated to form a structure.
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.

The film thickness of the phase shift layer 12 is set according to the optical properties required for the phase shift layer 12, and changes according to the composition ratio of Cr, N, C, O, and the like. The film thickness of the phase shift layer 12 can be 50 nm to 150 nm.

For example, the composition ratio in the phase shift layer 12 is selected from a range of carbon content (carbon concentration) of 0.5 atm % to 10.3 atm %, and oxygen content (oxygen concentration) 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% Further, the composition ratio can be set so that the composition ratio of Cr, N, C, O, etc. is 100 atm % in total, so that the composition ratio can be selected from each range. Therefore, in the phase shift layer 12, the total composition ratio of Cr, N, C, O, etc. is appropriately selected from the above ranges so that the total composition ratio of Cr, N, C, O, etc. is 100 atm % in order to exhibit the predetermined optical characteristics.

Specifically, as an example of the composition ratio in the phase shift layer 12, it is possible to set the carbon concentration to about 2 atm %, the oxygen concentration to about 73 atm %, the chromium concentration to about 22.5 atm %, and the nitrogen concentration to about 2 atm %. is. In this case, if it is not 100 atm %, it does not mean that the balance has some other composition, it simply indicates that there is a measurement error and an error in the addition.

As a result, 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, for example, the film thickness It can be set to about 90 nm.
The composition ratio and film thickness of the phase shift layer 12 are set according to the optical properties required for the phase shift mask 10 to be manufactured, and are not limited to the above values.

On the surface of the phase shift layer 12, a high carbon region 12c having a high carbon concentration of about 3.5 atm % or more is formed. 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.

Moreover, the composition ratio of elements other than carbon in the high-carbon region 12 c has the same composition ratio of Cr, N, O, etc. as that of the phase shift layer 12 .
That is, the high-carbon region 12c may also be configured by laminating one or more selected from Cr oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides. can. Furthermore, the high carbon regions 12c can have different compositions across the thickness.

As will be described later, the high-carbon region 12c has a predetermined adhesiveness (hydrophobicity), a thickness so as to obtain predetermined optical characteristics, and a composition ratio (atm%) of Cr, N, C, and O. be done. In the high-carbon region 12c, by increasing the carbon concentration in the chromium compound, the hydrophilicity can be reduced, the hydrophobicity can be improved, and the contact angle of water can be 50 degrees or more. Thereby, the adhesion between the high carbon region 12c and the photoresist layer 15 can be improved.

In the high-carbon region 12c, the carbon concentration at the outermost surface is set to about 1.5 to 2 times the carbon concentration in the phase shift layer 12 that is close to the glass substrate 11 in the thickness direction.
Specifically, the average carbon concentration in the phase shift layer 12 is about 2%, 1 to 3 atm%, while the highest carbon concentration in the high carbon region 12c is about 6 atm%, at least 5.5 atm% or more, It can be 5 atm % or more.

The film thickness of the high-carbon region 12c is determined by the conditions required for the high-carbon region 12c, that is, film properties such as adhesion (hydrophobicity) to the photoresist layer 15 described later and optical properties required for the phase shift layer 12. set by The film characteristics of these light shielding layers 14 change depending on the composition ratio of Cr, N, C, O and the like. The film thickness of the high carbon region 12c can be set depending on the optical properties required for the phase shift mask 10, in particular.

The high carbon region 12c can be set to have a film thickness of 10 nm or less. Specifically, the high carbon region 12c has a film thickness of about 0.5 to 10 nm, preferably about 2 to 5 nm, about 3 to 6 nm, about 1 to 4 nm, about 1 to 6 nm, about 2 to 4 nm, 3 to It can be set on the order of 5 nm.

Here, as will be described later, the high-carbon region 12c only needs to maintain predetermined states of wettability on the surface, contact angle of water, and adhesion to the resist layer 15, so that the surface properties thereof should be exhibited. is possible, there is no need to limit the film thickness or the like. However, if the high-carbon region 12c is too thick, such as about 15 nm or more, the optical properties of the phase shift layer 12 may be affected, which may affect the optical properties of the mask layer, which is not preferable.

The high-carbon region 12c has the highest carbon concentration at its outermost surface, and the carbon concentration gradually decreases as it approaches the glass substrate 11 in the thickness direction. It has a graded carbon concentration such that

Here, the carbon concentration in the high-carbon region 12c means the carbon concentration at the outermost surface, which is involved in surface properties. In other words, as will be described later, the topmost surface of the high carbon region 12c becomes extremely shallow with a slight thickness dimension due to processes such as etching, cleaning, etc. in the phase shift mask blanks manufacturing process and the photomask manufacturing process. Even if it is removed, the carbon concentration on the surface of the remaining portion should be set to be within the above-described predetermined range.

Therefore, when it is assumed that the surface of the high-carbon region 12c is removed by the above-described treatment, the carbon concentration, the concentration gradient, and the thickness are adjusted so as to maintain a predetermined carbon concentration. can be set.

By setting the film thickness and composition of the high-carbon region 12c as described above, the adhesiveness to the photoresist layer 15 used for etching a chromium-based film, for example, is improved during patterning formation in photolithography. Since the etchant does not permeate at the interface with the photoresist layer 15, a good pattern shape can be obtained and a desired pattern can be formed.

If the high-carbon region 12c is not set to meet the above conditions, the photoresist layer 15 peels off without a predetermined adhesion to the photoresist layer 15, and the etchant penetrates the interface. It is not preferable because it becomes impossible to perform pattern formation. In addition, if the film thickness of the high-carbon region 12c is not set according to the above conditions, it becomes difficult to set the optical characteristics of the mask layer as a photomask to the desired conditions, or the mask pattern is not preferable because the cross-sectional shape of the

Here, in the high carbon region 12c and the phase shift layer 12, it is possible to reduce the hydrophilicity by increasing the oxygen concentration and the nitrogen concentration in the chromium compound, improve the hydrophobicity, and increase the adhesion. be. At the same time, the refractive index and extinction coefficient are lowered by increasing the oxygen concentration and nitrogen concentration in the chromium compound, or the refractive index and extinction coefficient are lowered by lowering the oxygen concentration and nitrogen concentration in the chromium compound. It is also possible to increase the value of

The method of manufacturing the phase shift mask blanks according to the present 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. The high carbon region 12c is formed at the same time as the film or after the film formation.
In addition, when other layers are provided in addition to the high-carbon region 12c and the phase shift layer 12, a step of forming the corresponding layers can be provided.

Hereinafter, the phase shift mask blanks and the method of manufacturing the phase shift mask according to the present embodiment will be described with reference to the drawings.

FIG. 3 is a cross-sectional view showing the manufacturing process of the phase shift mask blanks and the phase shift mask in this embodiment. FIG. 4 is a cross-sectional view showing the manufacturing process of the phase shift mask blanks and the phase shift mask in this embodiment. FIG. 5 is a cross-sectional view showing the phase shift mask in this embodiment. FIG. 6 is a flow chart showing the manufacturing process of the phase shift mask blanks and the phase shift mask in this embodiment.
In the phase shift mask (photomask) 10 in this embodiment, as shown in FIG. 5, a pattern is formed in the phase shift layer 12, which is a mask layer laminated as the phase shift mask blanks 10B, and the high carbon region 12c. assumed.

First, the manufacturing method of the phase shift mask blanks 10B in this embodiment will be described based on the drawings. The phase shift mask blank 10B in this embodiment is manufactured by the manufacturing apparatus shown in FIG. 7 or FIG.
FIG. 7 is a schematic diagram showing a manufacturing apparatus for phase shift mask blanks in this embodiment.

The manufacturing apparatus S10 shown in FIG. 7 is an apparatus capable of inter-back sputtering. The manufacturing apparatus S10 has a load/unload chamber S11 and a film formation chamber (vacuum processing chamber, film formation section) S12.

A transport mechanism S11a and an exhaust mechanism S11f are provided in the loading/unloading chamber S11.
The transport mechanism S11a transports the glass substrate 11 loaded from the outside to the film forming chamber S12. The transport mechanism S11a transports 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 for roughly evacuating 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.

The film formation chamber S12 is provided with 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 exhaust mechanism S12f as film formation mechanisms. ing.

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 can also carry in the glass substrate S from the loading/unloading chamber S11. The substrate holding mechanism S12a can also carry out the glass substrate 11 to the loading/unloading chamber S11.

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 source S12d applies a negative sputtering voltage to the cathode electrode (backing plate) S12c having the target S12b.

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

Specifically, in the film forming mechanism of the film forming 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. FIG.

At the same time, in the film forming mechanism of the film forming chamber S12, as the gas supplied from the gas introduction mechanism S12e, the process gas contains carbon, nitrogen, oxygen, etc., corresponding to the film formation of the phase shift layer 12, and argon. , and a sputtering gas such as nitrogen gas are set as a predetermined gas partial pressure.
In addition, the high vacuum exhaust mechanism S12f performs exhaust according to film forming conditions.
Also, in the film forming mechanism S13, the sputtering voltage applied from the power supply S12d to the backing plate S12c is set corresponding to the film formation of the phase shift layer 12. FIG.

In the manufacturing apparatus S10 shown in FIG. 7, a phase shift layer 12 as a mask layer is first formed by sputtering in a film forming chamber (vacuum processing chamber) S12 on a glass substrate 11 carried in from a loading/unloading chamber S11. to form a film. Next, the high carbon region 12c is formed by sputtering film formation in the film formation chamber (vacuum processing chamber) S12. At this time, the film forming gas supplied to the film forming 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 loading/unloading chamber S11.

During film formation, a sputtering gas and a reaction gas are supplied from the gas introduction mechanism S12e to the film formation chamber S12, and a sputtering voltage is applied to the backing plate (cathode electrode) S12c from an external power supply. Alternatively, a predetermined magnetic field may be formed on the target S12b by a magnetron magnetic circuit. Ions of the sputtering gas excited by the plasma in the film-forming chamber S12 collide with the target S12b of the cathode electrode S12c to eject particles of the film-forming material. After the ejected particles are combined with the reaction gas, they adhere to the glass substrate S, thereby forming a predetermined film on the surface of the glass substrate S. FIG.

FIG. 8 is a schematic diagram showing a manufacturing apparatus for manufacturing phase shift mask blanks in this embodiment.
The manufacturing apparatus S20 shown in FIG. 8 is an apparatus capable of in-line sputtering. The manufacturing apparatus S20 has a load chamber S21, a film formation chamber (vacuum processing chamber, film formation section) S22, and an unload chamber S23.

A transport mechanism S21a and an exhaust mechanism S21b are provided in the load chamber S21.
The transport mechanism S21a transports the glass substrate 11 loaded from the outside to the film forming chamber S22. The exhaust mechanism S21b is a rotary pump or the like for roughly evacuating the inside of the load chamber S21.
The load chamber S21 is connected to a film forming chamber (vacuum processing chamber) S22 via a sealing mechanism S27.

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.

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 can also load the glass substrate 11 from the load chamber S21. The substrate holding mechanism S22a can also unload the glass substrate 11 to the unload chamber S23.

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. FIG.
A cathode electrode (backing plate) S22c, a power source S22d, a gas introduction mechanism S22e, and a high vacuum evacuation mechanism S22f are configured to supply materials for forming the phase shift layer 12, the high carbon region 12c, and the like.

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 forming chamber S22.
The high-vacuum exhaust mechanism S22f is, for example, a turbo-molecular pump that evacuates the inside of the film forming chamber S22 to a high vacuum.
The film formation chamber S22 is connected to the unload chamber S23 via a sealing mechanism S28.

A transport mechanism S23a and an exhaust mechanism S23b are provided in the unload chamber S23.
The transport mechanism S23a transports the glass substrate 11 loaded from the film forming chamber S22 to the outside. The exhaust mechanism S23b is a rotary pump or the like for roughly evacuating the inside of the unload chamber S23.

In the manufacturing apparatus S20 shown in FIG. 8, the phase shift layer 12 and the high carbon region 12c are formed by sputtering film formation in the film formation chamber (vacuum processing chamber) S22 on the glass substrate 11 carried in from the load chamber S21. . 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 the unload chamber S23.

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

Here, in the description of the manufacturing method of the phase shift mask blanks 10B in this embodiment, the processing using the manufacturing apparatus S20 shown in FIG. 8 will be described. When the phase shift mask blanks MB are manufactured by the manufacturing apparatus S10 shown in FIG. 7, the code of the S20 series should be read as the S10 series, and the unload chamber S25 should be read as the load/unload chamber S11 and the like. .

In the substrate preparation step S00 shown in FIG. 6, the glass substrate S subjected to the above-described surface treatment and the like is prepared. After that, the glass substrate 11 is loaded into the 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 vacuumed by the exhaust mechanism S21b.

In this state, the sealing mechanism S27 is released, the glass substrate 11 is transferred by the transfer mechanism S21a, the glass substrate 11 transferred by the substrate holding mechanism S22a is received, and the glass substrate is placed in the film formation chamber (vacuum processing chamber) S22. 11 is brought in.
In the film forming chamber S22, the sealing mechanism S27 is sealed after the glass substrate 11 is loaded.
In the film formation chamber (vacuum processing chamber) S22, the glass substrate 11 is held by the substrate holding mechanism S22a.

In the phase shift layer film forming step S01 shown in FIG. 6, in the film forming chamber (vacuum processing chamber) S22 shown in FIG. A sputtering gas and a reaction gas are supplied from the gas introduction mechanism S22e to the film formation chamber S22, and a sputtering voltage is applied to the backing plate (cathode electrode) S22c from an external power source. Alternatively, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputtering gas excited by the plasma in the film-forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film-forming material. Then, after the ejected particles are combined with the reaction gas, they adhere to the glass substrate S, thereby forming the phase shift layer 12 on the surface of the glass substrate 11 .

Here, the target S22b is replaced with a target S22b having a composition necessary for forming the phase shift layer 12 in advance. A target made of chromium is presented as the target S22b. Further, as a film forming gas necessary for forming the phase shift layer 12, an oxygen-containing gas, a carbon-containing gas, a nitrogen-containing gas, etc. are supplied at a predetermined flow rate from the gas introduction mechanism S22e, and each partial pressure is controlled. to bring its composition within the set range.
At this time, the phase shift layer 12 to be deposited has a predetermined oxygen composition ratio, carbon composition ratio, nitrogen composition ratio, and chromium composition ratio in the thickness direction, as shown in FIGS. , respectively.

When forming the phase shift layer 12 by changing the composition in the film thickness direction, it is also possible to vary individual gas partial pressures in the atmosphere gas according to the film thickness. In particular, when forming the high carbon region 12c, the carbon-containing gas is supplied and switched to control its partial pressure so that its composition is within a set range.

Here, examples of the oxygen-containing gas include CO ₂ (carbon dioxide), O ₂ (oxygen), N ₂ O (dinitrogen monoxide), NO (nitrogen monoxide), CO (carbon monoxide), and the like. can.
Carbon-containing gases include CO ₂ (carbon dioxide), CH ₄ (methane), C ₂ H ₆ (ethane), CO (carbon monoxide), and the like.
Furthermore, nitrogen-containing gases include N ₂ (nitrogen gas), N ₂ O (dinitrogen monoxide), NO (nitrogen monoxide), N ₂ O (dinitrogen monoxide), NH ₃ (ammonia), and the like. be able to.
It should be noted that the target S22b can be exchanged if necessary in the film formation of the phase shift layer 12 and the high carbon region 12c. For example, a target material with a high carbon content can be considered.

In the high carbon region forming step S02 shown in FIG. 6, in the film forming chamber S22 shown in FIG. 8, the inside of the film forming chamber S22 is evacuated to a high vacuum by the high vacuum evacuation mechanism S22f. A sputtering gas and a reaction gas are supplied from the gas introduction mechanism S22e to the film formation chamber S22, and a sputtering voltage is applied to the backing plate (cathode electrode) S22c from an external power supply. Alternatively, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputtering gas excited by the plasma in the film-forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film-forming material. Then, after the ejected particles are combined with the reaction gas, they adhere to the glass substrate S, thereby forming a film of the high carbon region 12c on the surface of the glass substrate S (FIG. 1).

Here, the target S22b can be replaced in advance with a composition necessary for film formation of the high carbon region 12c. Alternatively, as a film forming gas necessary for film forming of the high carbon region 12c, a predetermined flow rate of an oxygen-containing gas, a carbon-containing gas, a nitrogen-containing gas, or the like is supplied from the gas introduction mechanism S22e, and the partial pressure thereof is controlled. to bring its composition within the set range.

Specifically, CO ₂ (carbon dioxide) can be selected as the carbon-containing gas, and the partial pressure of this carbon-containing gas can be increased compared to the phase shift layer forming step S01. Alternatively, the gas flow rate of the carbon-containing gas can be increased compared to the phase shift layer deposition step S01.
At this time, as shown in later-described FIGS. 9 to 12, the high-carbon region 12c to be formed has a predetermined oxygen composition ratio, carbon composition ratio, nitrogen composition ratio, and chromium composition ratio in the thickness direction. , respectively.

Furthermore, in addition to the deposition of the phase shift layer 12 and the high carbon region 12c, when depositing other films, the deposition is performed by sputtering under the sputtering conditions of the corresponding target, gas, etc., or by another deposition method. The corresponding films are laminated to form the phase shift mask blank 10B of this embodiment.

As the photoresist layer forming step S03 shown in FIG. 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 (FIG. 2). The photoresist layer 15 may be positive or negative, but may be positive. A liquid resist, an adhesive film, or the like is used as the photoresist layer 15 .

The photoresist layer (resist layer) 15 may be a GRX-M series resist material manufactured by Nagase ChemteX Co., Ltd., which is generally used for metal etching for flat displays, or the like.

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

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

Next, in a cleaning step S06 shown in FIG. 6, photoresist pattern 15P1 is removed using a predetermined cleaning liquid.
Sulfuric acid hydrogen peroxide mixture or ozone water can be used as the cleaning liquid.

As a result, as shown in FIG. 5, a phase shift mask (a phase shift mask ( photomask) 10 can be obtained.

According to the phase shift mask 10 of the present embodiment, in the phase shift mask blank 10B in which the single layer phase shift layer 12 is laminated as the mask layer which is the optical layer, the extremely thin high carbon region 12c is formed on the surface of the phase shift layer 12. By forming, the wettability on the surface of the phase shift layer 12 is improved, the adhesion with the photoresist layer 15 is improved, and the interface between the phase shift layer 12 and the photoresist layer 15 in the phase shift pattern formation step S05 It is possible to prevent the etchant from permeating the phase shift layer 12 and the photoresist layer 15 from progressing at the interface between the phase shift layer 12 and the photoresist layer 15 . As a result, the side wall of the pattern edge portion of the phase shift pattern 12P1, that is, the side surface perpendicular to the surface of the glass substrate 11 is hollowed out from the originally planned vertical pattern shape to the lower side of the photoresist pattern 15P1. It is possible to prevent the pattern shape accuracy of the phase shift pattern from deteriorating.

A second embodiment of the phase shift mask blanks and phase shift mask according to the present invention will be described below.
This embodiment differs from the above-described first embodiment in the method of forming the high-carbon region, and the description of other configurations corresponding to those of the above-described first embodiment is omitted.

The high-carbon region 12c according to the present embodiment is formed by forming the phase shift layer 12 and then plasma-treating the surface in a carbon-containing gas atmosphere. Here, carbon can be contained by forming plasma in a 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 the carbon-containing gas, gases such as methane, carbon dioxide, and carbon monoxide can be used as in the first embodiment.

In this embodiment, it is possible to stably transform only the surface layer of the phase shift mask into a desired state.

A third embodiment of the phase shift mask blanks and phase shift mask according to the present invention will be described below.
This embodiment differs from the above-described first embodiment in the method of forming the high-carbon region, and the description of other configurations corresponding to those of the above-described first embodiment is omitted.

The high-carbon region 12c according to the present embodiment is formed by depositing the phase shift layer 12, applying a carbon-containing material to the surface, and performing plasma treatment in that state. Here, in order to contain carbon, an organic compound such as hexamethyldisiloxane as a carbon-containing material is applied to the surface of the phase shift layer 12 and placed in the plasma processing space, thereby causing a phase shift with respect to the plasma. This can be done by exposing the surface of the layer 12 under prescribed conditions for a prescribed period of time.

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

Examples of the present invention will be described below.
Here, as specific examples of the phase shift layer 12 and the high-carbon region 12c in the present invention, confirmation tests thereof will be described.

<Experimental example 1>
As Experimental Example 1, a film of a chromium compound is formed as a phase shift layer on a glass substrate using a sputtering method or the like. The chromium compound film formed here is a film containing chromium, oxygen, nitrogen, carbon, or the like. As the phase shift layer, a high carbon region was formed on the outermost surface. The formation of the high carbon region formed an extremely thin film with a different composition concentration and an increased carbon concentration as the outermost layer.

The specifications for the phase shift layer deposition are shown below.
・Carbon-containing gas; CO ₂ (carbon dioxide)
・Target: Chromium Below, the specifications in the high-carbon region are shown.
・Carbon-containing gas: mixed gas of CH ₄ (methane) and argon ・Target: chromium ・As for changes in gas supply during film formation, the target gas flow ratio is almost constant. Only the carbon-containing gas is added and the flow ratio is increased corresponding to the film thickness of the high carbon region.

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

<Experimental example 2>
As Experimental Example 2, similarly to Experimental Example 1, a film of a chromium compound is formed as a phase shift layer using a sputtering method or the like. In Experimental Example 2, no high carbon region was formed.

The composition of this film was evaluated using Auger electron spectroscopy.
The results are shown in FIGS. 9-12.
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 in the phase shift layer of Experimental Example 1. FIG.

<Contact angle measurement>
Next, in order to see the wettability on the surface of Experimental Examples 1 and 2, the contact angle of water on the surface is 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 the photographed image.
The results are shown in FIGS. 13 and 14. FIG.
As shown in FIGS. 13 and 14, in Experimental Example 1 with a high surface carbon concentration, the water contact angle was 58 degrees, and in Experimental Example 2 with a low surface carbon concentration, the water contact angle was 26 degrees. .

<Measurement of penetration width>
Next, as Experimental Example 4, as confirmation of the adhesion with the photoresist layer on the surface of Experimental Examples 1 and 2, after forming a resist pattern, etching was performed, and the penetration width due to the penetration of the etchant was measured.

The patterning specifications are shown below.
Resist; Resist type GRX-M237
film thickness 735nm
Pre-bake 87°C 48min
Exposure: Contact exposure machine (Tamarack)
Development: DIP type developer AZ DEVELOPER (diluted with 50% pure water)
Development time: 0 sec more than specified Etching: Paddle type Etchant: MPM-E
Etching time; more than 0 sec than specified

Cross sections of the patterned phase shift pattern and resist pattern were observed. SEM images thereof are shown in FIGS. In each figure, the phase shift layer is shown as Cr-PSM.
As shown in FIGS. 15 and 16, in Experimental Example 2, penetration occurred and the interface was hollowed out by about 150 nm, whereas in Experimental Example 1, penetration did not occur, It can be seen that the phase shift layer and the resist layer are in close contact at the interface.

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

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

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

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. It is also found that the shape accuracy in pattern formation can be ensured by providing the high-carbon region, or by performing resist formation and etching with the high-carbon region remaining.

As an example of utilization of the present invention, miniaturization of masks for flat displays can be cited.

DESCRIPTION OF SYMBOLS 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 (11)

A phase shift mask blank having a mask layer serving as a phase shift mask,
having a phase shift layer laminated on a transparent substrate and containing chromium, oxygen and carbon;
The phase shift layer has an oxygen concentration of 70% or more in 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 separated from the transparent substrate in the film thickness direction.
A phase shift mask blank characterized by: The high carbon region in the phase shift layer is 10 nm or less in the film thickness direction,
2. The phase shift mask blank according to claim 1, characterized in that: 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 blanks according to claim 1 or 2, characterized in that: wherein the phase shift layer is positioned on the outermost surface of the mask layer laminated on the transparent substrate;
4. The phase shift mask blank according to any one of claims 1 to 3, characterized in that: A method for manufacturing a phase shift mask blank according to any one of claims 1 to 4,
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, carbon is contained in the surface of the phase shift layer to be laminated to form the high carbon region.
A method of manufacturing a phase shift mask blank characterized by: In the phase shift layer forming step,
forming the high-carbon region by setting the partial pressure of a carbon-containing gas as a supply gas in sputtering to contain carbon in the surface of the phase shift layer;
6. The method of manufacturing a phase shift mask blank according to claim 5, wherein: A phase shift mask manufactured from the phase shift mask blank according to any one of claims 1 to 4 or manufactured by the phase shift mask blank manufacturing method 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 in the entire film thickness direction, and a surface separated from the transparent substrate in the film thickness direction has a carbon concentration. Having a high carbon region of 3.5 atm% or more,
A phase shift mask characterized by: The high carbon region in the phase shift pattern is 10 nm or less in the film thickness direction,
8. A phase shift mask according to claim 7, characterized in that: The contact angle of water on 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 or 8, characterized in that: wherein the phase shift pattern is positioned on the outermost surface of the mask pattern laminated on the transparent substrate;
10. The phase shift mask according to any one of claims 7 to 9, characterized in that: A method for manufacturing a phase shift mask according to any one of claims 7 to 10,
a resist pattern forming step of forming a resist pattern on the mask layer;
A phase shift pattern forming step of forming a pattern on the phase shift layer;
has
In the phase shift pattern forming step, the high carbon region remains,
A method of manufacturing a phase shift mask, characterized by:

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