JP2020042208A - Mask blank, transfer mask and method for manufacturing semiconductor device - Google Patents

Abstract

To provide a mask blank having a function of transmitting exposure light of an ArF excimer laser at a predetermined transmittance and having a reduced reflectance on a back surface.SOLUTION: The mask blank includes a pattern-forming thin film disposed on one main surface of a light-transmitting substrate, and an antireflection film disposed on the other main surface and having a stacked structure of, from the light-transmitting substrate side, a first layer, a second layer and a third layer. Refractive indices n, n, nof the first layer, the second layer and the third layer, respectively, at a wavelength of exposure light by an ArF excimer laser satisfy the relationship of n<nand n>n. Extinction coefficients k, k, kof the first layer, the second layer and the third layer, respectively, at the wavelength of the exposure light satisfy the relationship of k>k>k. Film thicknesses d, d, dof the first layer, the second layer and the third layer, respectively, satisfy the relationship of d>dand d<d.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mask blank and a transfer mask manufactured using the mask blank. The present invention also relates to a method for manufacturing a semiconductor device using the above-described transfer mask.

  Generally, in a manufacturing process of a semiconductor device, a fine pattern is formed using a photolithography method. Further, in order to form this fine pattern, a number of substrates, which are usually called transfer masks, are used. In miniaturizing a pattern of a semiconductor device, it is necessary to shorten the wavelength of an exposure light source used in photolithography in addition to miniaturizing a mask pattern formed on a transfer mask. In recent years, the wavelength of an exposure light source for manufacturing semiconductor devices has been shortened from a KrF excimer laser (wavelength: 248 nm) to an ArF excimer laser (wavelength: 193 nm).

As a type of transfer mask, a halftone phase shift mask is known in addition to a conventional binary mask having a light-shielding pattern made of a chromium-based material on a light-transmitting substrate.
Patent Literature 1 discloses a binary mask blank including a light-shielding film and front and rear anti-reflection films. In Patent Document 1, in order to suppress a flare (Flare) affecting adjacent shots due to reflection from a light-shielding band and an excess exposure amount error (Dose Error) in a pattern area, a light-shielding film is provided under the light-shielding film. formed in contact, silicon, transition metals, including oxygen and nitrogen, the refractive index _{n 2} is 1.0 to 3.5 of the membrane, the extinction coefficient _{k 2} of the film of 2.5 or less, the thickness t2 is 5 A backside antireflection film of 40 nm is provided. The reflectivity (hereinafter, referred to as back surface reflectivity) with respect to the incidence of light from the transparent substrate side is about 30% or less, and specifically, as shown in the embodiment, about 29% or about 23%. % Binary mask blank is realized.

  Patent Document 2 discloses a photomask having a transparent substrate 11, a pattern 12, and a thin film 13 made of calcium fluoride, intended to perform exposure that is less affected by peripheral patterns. The pattern 12 is formed on the first main surface of the transparent substrate 11, and has at least one of a light shielding film, a translucent film, and a phase control film. The thin film 13 made of calcium fluoride is formed on the second main surface of the transparent substrate 11 and functions as an anti-reflection film that suppresses re-reflected light on the back surface of the transparent substrate 11.

  In recent years, an illumination system used for performing exposure transfer on a resist film on a semiconductor device has become more sophisticated and complicated. Patent Literature 3 discloses a method of configuring an irradiation source of a lithographic apparatus to improve the imaging of a mask pattern on a substrate. The method comprises dividing an illumination source into groups of pixels, each group comprising one or more source points in a pupil plane of the illumination source, and changing a polarization state of each group of pixels. Determining a gradual effect on each of the plurality of critical dimensions resulting from a change in the polarization state of each group of pixels, and using the determined gradual effects to determine a first plurality of each of the plurality of critical dimensions. Calculating an initial illumination source; and using the calculated first plurality of sensitivity factors to calculate a lithographic response as a result of a change in the polarization state of the initial illumination source pixels. Iteratively calculating a metric, wherein a change in the polarization state of an initial source pixel group produces a modified illumination source; Based on the results in which a step of adjusting the initial radiation source.

Japanese Patent No. 5054766 JP 2001-337441 A JP 2012-74695 A

  In recent years, further miniaturization of a transfer pattern has been demanded, and an illumination system used when performing exposure transfer has been sophisticated and complicated. For example, in the illumination system disclosed in Patent Document 3, control is performed so as to optimize the position and angle of the irradiation source. In such a complicated illumination system, when exposing a transfer mask with exposure light of a relatively short wavelength ArF excimer laser, stray light due to multiple reflections is generated in the translucent substrate of the transfer mask. It is easier. In the photomask provided with the thin film 13 made of calcium fluoride in Patent Document 2, re-reflected light on the back surface of the substrate (light traveling inside the substrate is reflected on the back surface of the substrate, and the inside of the substrate is reflected on the back surface). Of the light emitted from the irradiation source to the back surface (the other main surface) of the substrate, the light reflected on the back surface to the irradiation source side although the light traveling toward the semiconductor device side can be suppressed. Light (backside reflected light) could not be sufficiently suppressed. For this reason, the back surface reflected light interferes with the light from the irradiation source, which hinders further improvement in transfer accuracy.

  Therefore, the present invention has been made to solve the conventional problem, and in a mask blank having a pattern forming thin film on one main surface of a light-transmitting substrate, the mask blank is exposed to ArF excimer laser exposure light. A thin film having a function of reducing the reflectance of the other main surface of the light-transmitting substrate with respect to the exposure light (the reflectance of the back surface of the substrate) while having a function of transmitting light at a predetermined transmittance. It is intended to provide a mask blank provided on a main surface. It is another object of the present invention to provide a transfer mask manufactured using the mask blank. An object of the present invention is to provide a method for manufacturing a semiconductor device using such a transfer mask.

In order to achieve the above object, the present invention has the following configuration.
(Configuration 1)
A mask blank comprising a light-transmitting substrate having two opposing main surfaces and a pattern-forming thin film provided on one of the main surfaces,
An anti-reflection film having a structure in which a first layer, a second layer, and a third layer are stacked in this order from the light-transmitting substrate side on the other main surface;
When the refractive indices of the first layer, the second layer, and the third layer at the wavelength of the exposure light of the ArF excimer laser are n ₁ , n ₂ , and n ₃ , respectively, n ₁ <n ₂ and n ₂ > n. _Satisfy the relationship of ₃ ,
The first layer, when the second layer and the extinction coefficient at the wavelength of the exposure light of the third layer was _{k 1,} k 2, _{k 3 respectively,} satisfy the relationship of k _1> k 2> _{k 3} ,
The first layer, when the thickness of the second layer and the third layer and _{d 1,} d 2, _{d 3, respectively,} and satisfy the relationship d 1> _{d 2} and _d 2 _{<d 3} Mask blank.

(Configuration 2)
When the refractive index of the light-transmitting substrate at the wavelength of the exposure light is n _S , the relationship of n _S <n ₁ <n ₂ is satisfied;
_2. The mask blank according to Configuration 1, wherein a relationship of k _S <k ₂ <k ₁ is satisfied, where k _S is an extinction coefficient of the translucent substrate at the wavelength of the exposure light.
(Configuration 3)
The mask blank according to Configuration 1 or 2, wherein the first layer is provided in contact with a surface of the translucent substrate.

(Configuration 4)
The first layer is formed of a material including silicon and nitrogen, or a material including one or more elements selected from a semimetal element and a nonmetal element, and silicon and nitrogen,
The second layer is formed of a material including silicon and nitrogen, or a material including one or more elements selected from metalloid elements and nonmetal elements, and silicon and nitrogen,
The structure according to Claim 1, wherein the third layer is formed of a material composed of silicon and oxygen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and oxygen. 3. The mask blank according to any one of 3.
(Configuration 5)
The mask blank according to Configuration 4, wherein the second layer has a higher nitrogen content than the first layer.

(Configuration 6)
The pattern forming thin film includes a phase shift film,
The phase shift film has a structure in which a first A layer, a second A layer, and a third A layer are stacked in this order from the translucent substrate side,
When the refractive indices of the first A layer, the second A layer, and the third A layer at the wavelength of the exposure light are n _1A , n _2A , and n _3A , respectively, the relationship of n _1A > n _2A and n _2A <n _3A is satisfied. The filling,
When the extinction coefficients of the first A layer, the second A layer, and the third A layer at the wavelength of the exposure light are k _1A , k _2A , and k _3A , respectively, k _1A <k _2A and k _2A > k _3A Fill the relationship,
When the thicknesses of the first A layer, the second A layer, and the third A layer are d _1A , d _2A , and d _3A , respectively, the relationship of d _1A <d _3A and d _2A <d _3A is satisfied. 6. The mask blank according to any one of the configurations 1 to 5, wherein
(Configuration 7)
7. The mask blank according to configuration 6, wherein the thickness d _3A of the third A layer is at least twice the thickness d _1A of the second A layer.

(Configuration 8)
The mask blank according to Configuration 6 or 7, wherein the first A layer is provided in contact with a surface of the translucent substrate.
(Configuration 9)
The first A layer, the second A layer, and the third A layer are formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and nitrogen. 9. The mask blank according to any one of Configurations 6 to 8, wherein:

(Configuration 10)
The mask blank according to Configuration 9, wherein the second A layer has a lower nitrogen content than the first A layer and the third A layer.
(Configuration 11)
The phase shift film has a function of transmitting the exposure light at a transmittance of 2% or more, and has passed through the air by the same distance as the thickness of the phase shift film with respect to the exposure light transmitted through the phase shift film. The mask blank according to any one of Configurations 6 to 10, having a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the exposure light.

(Configuration 12)
The pattern forming thin film includes a phase shift film,
The phase shift film has a structure in which a first B layer and a second B layer are stacked in this order from the transparent substrate side,
When the refractive index of the first B layer and the second B layer at the wavelength of the exposure light is n _1B and n _2B , respectively, the relationship of n _1B <n _2B is satisfied;
When the extinction coefficients at the wavelength of the exposure light of the first B layer and the second B layer are k _1B and k _2B , respectively, the relationship of k _1B <k _2B is satisfied;
The mask blank according to any one of Configurations 1 to 5, wherein the relationship of d _1B <d _2B is satisfied when the thickness of the first B layer and the thickness of the second B layer are d _1B and d _2B , respectively.

(Configuration 13)
13. The mask blank according to Configuration 12, wherein the first B layer is provided in contact with a surface of the translucent substrate.

(Configuration 14)
The first B layer is formed of a material including silicon, nitrogen, and oxygen, or a material including one or more elements selected from a semimetal element and a nonmetal element, and silicon, nitrogen, and oxygen;
The structure 12 or wherein the second B layer is formed of a material including silicon and nitrogen, or a material including one or more elements selected from a semimetal element and a nonmetal element and silicon and nitrogen. 14. The mask blank according to 13.
(Configuration 15)
15. The mask blank according to configuration 14, wherein the second B layer has a higher nitrogen content than the first B layer.

(Configuration 16)
The phase shift film has a function of transmitting the exposure light at a transmittance of 15% or more, and has passed the air by the same distance as the thickness of the phase shift film with respect to the exposure light transmitted through the phase shift film. The mask blank according to any one of Configurations 12 to 15, having a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the exposure light.
(Configuration 17)
17. A transfer mask, wherein a transfer pattern is provided on the translucent substrate or the pattern forming thin film in the mask blank according to any one of the constitutions 1 to 16.

(Configuration 18)
18. A method for manufacturing a semiconductor device, comprising a step of exposing and transferring a transfer pattern to a resist film on a semiconductor substrate using the transfer mask according to Configuration 17.

  The mask blank of the present invention has a function of transmitting at a predetermined transmittance to exposure light of an ArF excimer laser in a mask blank having a pattern forming thin film on one main surface of a light-transmitting substrate. A mask blank provided with a thin film having a function of reducing the reflectance of the other main surface of the light-transmitting substrate with respect to the exposure light of the ArF excimer laser (the back surface reflectance of the substrate) on the other main surface. can do.

It is a sectional view showing the composition of the mask blank in a 1st embodiment of the present invention. It is a sectional view showing composition of a mask blank in a 2nd embodiment of the present invention. It is sectional drawing which shows the structure of the mask blank in 3rd Embodiment of this invention. FIG. 3 is a schematic cross-sectional view illustrating a step of manufacturing the phase shift mask in the first embodiment of the present invention. FIG. 11 is a schematic cross-sectional view illustrating a step of manufacturing a phase shift mask in the second and third embodiments of the present invention.

  Hereinafter, embodiments of the present invention will be described. The inventors of the present application have a function of transmitting the exposure light of the ArF excimer laser (hereinafter, also simply referred to as “exposure light”) at a predetermined transmittance and a function of reducing the reflectance of the back surface of the substrate. We conducted intensive research on the means we have.

  In the case of performing exposure with exposure light of an ArF excimer laser, the back surface of the light-transmitting substrate (the main surface opposite to the one main surface on which the pattern forming thin film is provided; that is, the other main surface) is exposed from the air. When the exposure light is incident on the substrate, light reflected on the back surface of the light-transmitting substrate is generated by about 5% of the incident light (that is, the light intensity of the exposure light incident on the inside of the light-transmitting substrate is reduced by about 5%). I do.) In order to reduce the light reflected on the back surface of the light transmitting substrate, it is effective to provide an anti-reflection film on the back surface side of the light transmitting substrate. This anti-reflection film is also required to have a function of allowing a sufficient amount of exposure light to enter the interior of the translucent substrate, but to achieve both this function and the anti-reflection function requires a single-layer anti-reflection film. I found it difficult.

The present inventor further studied the layer structure of the antireflection film, the refractive index, extinction coefficient, and film thickness that each layer should satisfy. As a result, the antireflection film provided on the back surface (the other main surface) of the light-transmitting substrate has a structure in which the first layer, the second layer, and the third layer are stacked in this order from the light-transmitting substrate side. When the refractive indexes at the wavelength of the exposure light of the ArF excimer laser of the second layer and the third layer are n ₁ , n ₂ , and n ₃ , respectively, the relationship of n ₁ <n ₂ and n ₂ > n ₃ is satisfied. When the extinction coefficients at the wavelengths of the exposure light of the first layer, the second layer, and the third layer are k ₁ , k ₂ , and k ₃ , respectively, the relationship k ₁ > k ₂ > k ₃ is satisfied, and the first layer, When the thicknesses of the second layer and the third layer are d ₁ , d ₂ , and d ₃ , respectively, by satisfying the relations d ₁ > d ₂ and d ₂ <d ₃ , the exposure light of the ArF excimer laser is desired. Reflection that has the function of reducing the reflectance of the back surface of the substrate while having the function of transmitting at a transmittance of It found that to form a mask blank having a sealing film. The present invention has been made by the above intensive studies.

FIG. 1 is a cross-sectional view illustrating a configuration of a mask blank 100 according to the first embodiment of the present invention. The mask blank 100 of the present invention shown in FIG. 1 has a structure in which a pattern forming thin film 2 serving as an etching stopper and a hard mask film, a light shielding film 3 and a hard mask film 4 are laminated in this order on a light transmitting substrate 1. (In the present embodiment, the “pattern forming thin film 2” will be appropriately described as “etching stopper / hard mask film 2”.)
The translucent substrate 1 can be formed of quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (such as SiO ₂ —TiO ₂ glass), in addition to synthetic quartz glass. Among these, synthetic quartz glass has a high transmittance to ArF excimer laser light and is particularly preferable as a material for forming the light-transmitting substrate 1 of the mask blank. Translucent substrate 1, a refractive index _{n S} with respect to the exposure light is 1.5 to 1.6, and is preferably an extinction coefficient _{k S} is 0.1 or less. The lower limit of the extinction coefficient k _S of the transparent substrate 1 is 0.0.

  The etching stopper / hard mask film 2 needs to be a material having high etching selectivity with the light-shielding film 3 immediately above. In this embodiment, a chromium-based material is selected as the material of the etching stopper / hard mask film 2. Thereby, high etching selectivity with the light-shielding film 3 made of a silicon-based material or a tantalum-based material can be secured.

  The etching stopper / hard mask film 2 is made of a material containing chromium (Cr) and at least one element selected from nitrogen (N), oxygen (O), carbon (C), hydrogen (H) and boron (B). It is preferable to form with. Further, the material of the etching stopper and the hard mask film 2 may include a noble gas such as helium (He), argon (Ar), krypton (Kr), and xenon (Xe). Specifically, for example, materials such as CrN, CrON, CrOC, and CrOCN are exemplified. It is preferable that the composition of the etching stopper / hard mask film 2 is substantially constant, and specifically, the difference in the content of each constituent element in the thickness direction is less than 10 atomic%.

  It is preferable that the chromium content of the etching stopper / hard mask film 2 be 50 atomic% or more in that the side etching that occurs when patterning by dry etching can be suppressed. The etching stopper and hard mask film 2 preferably has a chromium content of 80 atomic% or less in that the etching rate when patterning by dry etching can be sufficiently ensured.

  The method for forming the etching stopper and the hard mask film 2 is not particularly limited, but a sputtering film forming method is preferable. The sputtering film forming method is preferable because a film having a uniform thickness can be formed. Since a highly conductive target is used for forming the etching stopper and the hard mask film 2, it is more preferable to use DC sputtering, which has a relatively high film forming rate.

  The thickness of the etching stopper / hard mask film 2 is not particularly limited, but is preferably, for example, in the range of 3 nm to 20 nm, and more preferably, 3.5 nm to 15 nm.

Next, the light shielding film 3 will be described.
In the present embodiment, the light shielding film 3 is made of a material containing one or more elements selected from silicon and tantalum.
In the present embodiment, by selecting a silicon-based material or a tantalum-based material as the material of the light-shielding film 3, high etching selectivity with the etching stopper / hard mask film 2 made of a chromium-based material can be secured.

Examples of a material containing one or more elements selected from silicon and tantalum forming the light shielding film 3 include the following materials.
Examples of the material containing silicon include a material containing silicon and nitrogen, and a material containing one or more elements selected from semimetal elements and nonmetal elements in this material. In this case, the metalloid element is preferably at least one element selected from boron, germanium, antimony, and tellurium. In this case, the nonmetal element includes a nonmetal element in a narrow sense (nitrogen, carbon, oxygen, phosphorus, sulfur, selenium), a halogen, and a noble gas.

  Other suitable materials containing silicon for the light-shielding film 3 include materials containing one or more elements selected from oxygen, nitrogen, carbon, boron and hydrogen in silicon and transition metals. As the transition metal in this case, for example, molybdenum (Mo), tungsten (W), titanium (Ti), tantalum (Ta), zirconium (Zr), hafnium (Hf), niobium (Nb), vanadium (V), Cobalt (Co), nickel (Ni), ruthenium (Ru), tin (Sn), chromium (Cr), and the like. Such a material containing silicon and a transition metal has a high light-shielding performance, and the thickness of the light-shielding film 3 can be reduced.

  In addition, as the material containing tantalum, a material containing one or more elements selected from nitrogen, oxygen, boron and carbon in addition to tantalum metal is used. Specifically, for example, Ta, TaN, Preferred are TaO, TaON, TaBN, TaBO, TaBON, TaCN, TaCO, TaCON, TaBCN, TaBOCN and the like.

  The method for forming the light-shielding film 3 is not particularly limited, but a sputtering film forming method is preferable. The sputtering film forming method is preferable because a film having a uniform thickness can be formed. When the light-shielding film 3 is formed of a material composed of silicon and nitrogen, or a material containing one or more elements selected from a semimetal element and a nonmetal element in this material, the target has low conductivity, so that RF sputtering or It is preferable to form a film using ion beam sputtering. On the other hand, when the light-shielding film 3 is formed of a material containing at least one element selected from oxygen, nitrogen, carbon, boron and hydrogen or a material containing tantalum in silicon and a transition metal, the conductivity of the target is compared. Therefore, it is preferable to form the film using DC sputtering, which has a relatively high film forming speed.

  The light-shielding film 3 may have a single-layer structure or a laminated structure. For example, a two-layer structure of a light-shielding layer and a front-surface antireflection layer, or a three-layer structure in which a back-surface antireflection layer is added.

  The light-shielding film 3 is required to ensure a predetermined light-shielding property. For example, the optical density (OD) with respect to exposure light of an ArF excimer laser (wavelength 193 nm) effective for forming a fine pattern is required to be 2.8 or more. And more preferably 3.0 or more.

  The thickness of the light-shielding film 3 is not particularly limited, but is preferably 80 nm or less, more preferably 70 nm or less in order to form a fine pattern with high accuracy. On the other hand, since the light-shielding film 3 is required to secure a predetermined light-shielding property (optical density) as described above, the thickness of the light-shielding film 3 is preferably 30 nm or more, and more preferably 40 nm or more. More preferred.

  Further, as in the present embodiment, for the purpose of reducing the thickness of the resist film formed on the surface of the mask blank 100, a hard mask film made of a material having an etching selectivity with respect to the light shielding film 3 is formed on the light shielding film 3. It is sometimes referred to as an “etching mask film.”

  Since the hard mask film 4 functions as an etching mask when a pattern is formed on the light shielding film 3 by dry etching, the material of the hard mask film 4 has sufficient resistance to the dry etching environment of the light shielding film 3. It must be formed of a material. For dry etching of the light-shielding film 3 made of a silicon-based material or a tantalum-based material, a fluorine-based gas is usually used as an etching gas. It is preferable to use a chromium-containing material having sufficient etching selectivity with respect to the light-shielding film 3.

  Examples of the chromium-based material for forming the hard mask film 4 include a chromium compound obtained by adding one or more elements selected from elements such as oxygen, carbon, nitrogen, hydrogen, and boron to chromium. The hard mask film 4 is patterned by dry etching using a mixed gas of a chlorine-based gas and an oxygen gas using the pattern of the resist film formed on the surface of the mask blank 10 as a mask. It is preferable that the etching rate in dry etching using a mixed gas with oxygen gas is high, and from this viewpoint, the hard mask film 4 is preferably made of a material containing at least chromium and oxygen. The material of the hard mask film 4 may include a noble gas such as helium (He), argon (Ar), krypton (Kr), and xenon (Xe). Specifically, for example, materials such as CrN, CrON, CrOC, and CrOCN are exemplified. It is more preferable that the hard mask film 4 is a single layer film using the same material as the etching stopper and the hard mask film 2. In this case, the surface of the hard mask film 4 on the side opposite to the light-transmitting substrate 1 side and a region in the vicinity thereof are difficult to avoid the progress of oxidation, so that the single-layer film having a composition gradient portion with an increased oxygen content is used. Become.

  The method for forming the hard mask film 4 does not need to be particularly limited, but a sputtering film forming method is preferable. The sputtering film forming method is preferable because a film having a uniform thickness can be formed. Since a highly conductive target is used to form the hard mask film 4, it is more preferable to use DC sputtering, which has a relatively high film forming rate.

  Although the thickness of the hard mask film 4 does not need to be particularly limited, the hard mask film 4 functions as an etching mask when the light shielding film 3 immediately below is patterned by dry etching using a fluorine-based gas. Therefore, it is necessary to have a film thickness that does not disappear at least before the etching of the light shielding film 3 immediately below is completed. On the other hand, if the thickness of the hard mask film 4 is large, it is difficult to reduce the thickness of the resist pattern immediately above. From such a viewpoint, the thickness of the hard mask film 4 is preferably, for example, in a range of 3 nm to 20 nm, and more preferably, 3.5 nm to 15 nm.

Although not shown in FIG. 1, the mask blank of the present invention includes a mask blank having the above configuration and having a resist film on the surface.
The resist film is made of an organic material, and is preferably a resist material for electron beam lithography. In particular, a chemically amplified resist material is preferably used.
The resist film is usually formed on the surface of the mask blank by a coating method such as a spin coating method. The resist film is preferably formed to have a thickness of, for example, 200 nm or less from the viewpoint of forming a fine pattern. However, by providing the hard mask film 4, the resist film can be made thinner. It can be a film thickness.

Further, the mask blank 100 in the present embodiment includes an antireflection film 7 on the back surface (the other main surface) of the light-transmitting substrate 1. The antireflection film 7 has a structure in which a first layer 71, a second layer 72, and a third layer 73 are stacked from the light transmitting substrate 1 side. It is necessary that the desired anti-reflection film 7 has a desired transmittance and a desired back surface reflectance. For this purpose, in the antireflection film 7, the first layer 71, when the ArF excimer laser refractive index at the wavelength of the exposure light of the second layer 72 and third layer 73 was a _{n 1,} n 2, _{n 3,} respectively , N ₁ <n ₂ and n ₂ > n ₃ , and the extinction coefficients of the first layer 71, the second layer 72, and the third layer 73 at the wavelength of the exposure light are k ₁ , k ₂ , and k ₃ , respectively. The present inventor has found that it is necessary to satisfy the relationship of k ₁ > k ₂ > k ₃ .

On top of that, the refractive index _{n 1} of the first layer 71 is preferably less than 2.0, more preferably a 1.9 or less. The refractive index _{n 1} of the first layer 71 is preferable to be 1.0 or more, and more preferably 1.2 or more. Further, the extinction coefficient _{k 1} of the first layer 71 is preferably 1.0 or more, and more preferably 1.2 or more. Further, the extinction coefficient _{k 1} of the first layer 71 is preferable to be 2.2 or less, more preferably 2.0 or less. In addition, the refractive index n ₁ and the extinction coefficient k ₁ of the first layer 71 are numerical values derived by regarding the entire first layer 71 as one optically uniform layer (for the other layers described later). The refractive index and the extinction coefficient are similarly derived.)

The refractive index _{n 2} of the second layer 72 is preferable to be 2.0 or more, and more preferably 2.1 or more. The refractive index _{n 2} of the second layer 72 is preferable to be 3.0 or less, more preferably 2.8 or less. Extinction coefficient _{k 2} of the second layer 72 is preferably 0.5 or less, more preferably 0.4 or less. Further, the extinction coefficient _{k 2} of the second layer 72 is preferable to be 0.1 or more, and more preferably 0.2 or more.
The refractive index _{n 3} of the third layer 73 is preferable to be 1.8 or less, more preferably 1.7 or less. The refractive index _{n 3} of the third layer 73 is preferable to be 1.5 or more, and more preferably 1.55 or more. On the other hand, the extinction coefficient _{k 3} of the third layer 73 is preferable to be 0.1 or less, more preferably 0.05 or less.

When the refractive index of the light-transmitting substrate 1 at the wavelength of the exposure light is n _S , the relationship of n _S <n ₁ <n ₂ is satisfied, and the extinction coefficient of the light-transmitting substrate 1 at the wavelength of the exposure light is When k _S is satisfied, it is preferable that the relationship k _S <k ₂ <k ₁ is satisfied.

  The refractive index n and the extinction coefficient k of the thin film including the antireflection film 7 are not determined only by the composition of the thin film. The film density and crystal state of the thin film are also factors that influence the refractive index n and the extinction coefficient k. Therefore, conditions for forming a thin film by reactive sputtering are adjusted so that the thin film has a desired refractive index n and an extinction coefficient k. To form the first layer 71, the second layer 72, and the third layer 73 within the above-described range of the refractive index n and the extinction coefficient k, a noble gas and a reactive gas ( It is not limited only to adjusting the ratio of the mixed gas of oxygen gas and nitrogen gas. There is a wide variety of positional relationships, such as the pressure in the film formation chamber when forming a film by reactive sputtering, the power applied to the sputtering target, and the distance between the target and the transparent substrate 1. These film forming conditions are specific to the film forming apparatus, and are appropriately adjusted so that the formed first layer 71, second layer 72, and third layer 73 have desired refractive index n and extinction coefficient k. Is what is done.

In order to obtain desired transmittance and backside reflectance over the entire antireflection film 7, the thicknesses of the first layer 71, the second layer 72, and the third layer 73 are set to d ₁ and d ₂ , respectively. , when a _{d 3,} it is at least necessary to satisfy the relationship d 1> _{d 2} and _d 2 _{<d 3.}

Thickness _{d 1} of the first layer 71 is preferable to be 30nm or less, more preferably 25nm or less. The thickness _{d 1} of the first layer 71 is preferably at 14nm or more, and more preferably more than 17 nm.
Thickness _{d 2} of the second layer 72 is preferable to be 10nm or less, and more preferably 8nm or less. The thickness _{d 2} of the second layer 72 is preferably 4nm or more, and more preferably 5nm or more.
Thickness _{d 3} of the third layer 73 is preferable to be 20nm or less, and more preferably less 17 nm. The thickness _{d 3} of the third layer 73 is preferably 10nm or more, and more preferably 13nm or more.

The first layer 71 and the second layer 72 are preferably formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from semimetal elements and nonmetal elements, and silicon and nitrogen. Among these metalloid elements, it is preferable to include one or more elements selected from boron, germanium, antimony, and tellurium because the conductivity of silicon used as a sputtering target can be expected to be increased. In addition, it is preferable to include one or more elements selected from nitrogen, carbon, fluorine, and hydrogen among the nonmetallic elements. The non-metallic elements also include noble gases such as helium (He), argon (Ar), krypton (Kr), and xenon (Xe).
In addition, the third layer 73 is preferably formed of a material composed of silicon and oxygen, or a material composed of one or more elements selected from the above-mentioned metalloid elements and nonmetal elements, and silicon and oxygen. By forming the third layer 73 with such a material, it is possible to suppress the occurrence of haze that is likely to occur in a silicon-containing film having a high nitrogen content.

  The second layer 72 preferably has a higher nitrogen content than the first layer 71. The nitrogen content in the material forming the first layer 71 is preferably 40 atomic% or less, more preferably 35 atomic% or less. The first layer 71 needs to contribute to the transmittance of the antireflection film 7, but in order to increase both the difference in the refractive index and the difference in the extinction coefficient from the second layer, the refractive index increases, and This is because it is preferable to suppress the nitrogen content that causes the extinction coefficient to decrease. Further, the nitrogen content in the material forming the first layer 71 is preferably 10 atomic% or more, and more preferably 15 atomic% or more. If the nitrogen content is small, the extinction coefficient of the first layer 71 will be high, and the transmittance for exposure light will be greatly reduced.

The second layer 72 preferably has a nitrogen content of 50 atomic% or more, more preferably 55 atomic% or more, and is composed of stoichiometrically stable material Si ₃ N _4. Is more preferred. The second layer 72 is preferably formed of a material having a high refractive index, because the refractive index can be increased by increasing the nitrogen content.

  The oxygen content of the third layer 73 is preferably larger than the oxygen content of each of the first layer 71 and the second layer 72. The oxygen content of the third layer 73 is preferably at least 50 atomic%, more preferably at least 55 atomic%.

  The first layer 71 is preferably provided in contact with the other main surface (back surface) of the translucent substrate 1. The configuration in which the first layer 71 is in contact with the surface of the light-transmitting substrate 1 reduces the back surface reflectivity caused by the laminated structure of the first layer 71, the second layer 72, and the third layer 73 of the antireflection film 7. This is because a more effective effect can be obtained. Another thin film may be provided between the translucent substrate 1 and the antireflection film 7 as long as the effect on the effect of reducing the back surface reflectance of the antireflection film 7 is small. In this case, the thickness of the other thin film needs to be 10 nm or less, preferably 7 nm or less, and more preferably 5 nm or less. The extinction coefficient k of the material forming another thin film is preferably less than 0.1, more preferably 0.05 or less, and even more preferably 0.01 or less. In this case, the refractive index n of the material forming the other thin film is preferably 1.9 or less, and more preferably 1.7 or less. The material forming another thin film preferably has a refractive index n of 1.55 or more. The other thin film is preferably formed using a material containing silicon, aluminum, and oxygen. Further, another thin film may be formed of a material containing hafnium and oxygen.

  Although the first layer 71, the second layer 72, and the third layer 73 in the antireflection film 7 are formed by sputtering, any sputtering such as DC sputtering, RF sputtering, and ion beam sputtering can be applied. Considering the film formation rate, it is preferable to apply DC sputtering. In the case of using a target with low conductivity, it is preferable to apply RF sputtering or ion beam sputtering; however, in consideration of a film formation rate, it is more preferable to apply RF sputtering.

Further, although not particularly limited, before forming the anti-reflection film 7 on the rear surface of the light-transmitting substrate 1, the above-described etching stopper / hard mask film 2, light shielding film 3, and hard mask film 4 are formed through the transparent mask. It is preferable to form a film on the surface of the optical substrate 1.
Further, the antireflection film 7 may be formed over the entire back surface of the light-transmitting substrate 1, but is not limited thereto, and may be formed in a part of the rear surface of the light-transmitting substrate 1 (for example, the light-transmitting substrate 1). 1 may be formed in a region corresponding to a region outside a region where a transfer pattern to be set on the front side of the substrate 1 is formed (for example, a region outside a square having a side of 132 mm with reference to the center of the substrate). Good. This is preferable in that the amount of exposure light incident on the translucent substrate 1 can be maximized and the reflectance of the rear surface of the substrate can be reduced by the antireflection film 7. When the anti-reflection film 7 is formed in a partial area on the back surface of the translucent substrate 1, a shielding member is provided in a predetermined area of the translucent substrate 1 (an area where the anti-reflection film 7 is not formed). The sputtering may be performed in this state.

  In the mask blank 100 of the present embodiment, a configuration similar to that of the above-mentioned other thin film is formed between one main surface of the light-transmitting substrate 1 and the etching stopper / hard mask film 2 from one main surface side. A structure in which a thin film provided and a phase shift film having a single-layer structure made of a material containing silicon and oxygen are stacked in this order may be interposed. In this case, the phase shift film has a function of transmitting the exposure light with a transmittance of 90% or more, and the exposure light transmitted through the phase shift film passes through the air by the same distance as the thickness of the phase shift film. It preferably has a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the exposure light. Generally, when manufacturing a chromeless phase shift mask or an engraved Levenson type phase shift mask from a mask blank, the surface of the light-transmitting substrate is dug to form a phase shift pattern, but it is necessary to form a pattern on this phase shift film. Thus, a phase shift pattern can be formed without digging a substrate.

  The mask blank 100 of the present embodiment has the above-described configuration, and has a function of transmitting the exposure light of the ArF excimer laser at a predetermined transmittance, and also has a function of transmitting the back surface of the light-transmitting substrate 1. An antireflection film 7 having a function of reducing reflectance can be provided.

  FIG. 2 is a cross-sectional view illustrating a configuration of a mask blank 110 according to the second embodiment of the present invention. The mask blank 110 according to the present embodiment has a structure in which a pattern forming thin film 2 functioning as a phase shift film, a light shielding film 3 and a hard mask film 4 are stacked in this order on a light transmitting substrate 1 (this embodiment). In the description, the “pattern forming thin film 2” will be appropriately referred to as “phase shift film 2”.) The phase shift film 2 has a structure in which a first A layer 21, a second A layer 22, a third A layer 23, and a fourth A layer 24 are stacked from the light transmitting substrate 1 side. Note that the configurations of the translucent substrate 1, the antireflection film 7, and the resist film are the same as those described in the first embodiment, and a description thereof will not be repeated.

  The phase shift film 2 of the present embodiment has a function of transmitting the exposure light at a transmittance of 2% or more, and a function of transmitting the exposure light transmitted through the phase shift film 2 in the air by the same distance as the thickness of the phase shift film 2. And a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the transmitted exposure light. The transmittance of the phase shift film 2 for exposure light is preferably 3% or more, more preferably 4% or more. On the other hand, the transmittance of the phase shift film 2 of the present embodiment to exposure light is preferably 15% or less, more preferably 14% or less.

  The lower limit of the phase difference in the phase shift film 2 is preferably 155 degrees or more, and more preferably 160 degrees or more. On the other hand, the upper limit of the phase difference in the phase shift film 2 is preferably 190 degrees or less.

The phase shift film 2 has a structure in which a first A layer 21, a second A layer 22, and a third A layer 23 are stacked from the light transmitting substrate 1 side. The phase shift film 2, the 1A layer 21, the 2A layer 22 and the ArF excimer laser respectively _n 1A refractive index at the wavelength of the exposure light of the 3A layer _23, n _2A, when the _{n 3A, n 1A} > N _2A and n _2A <n _3A are satisfied, and the extinction coefficients of the first A layer 21, the second A layer 22, and the third A layer 23 at the wavelength of the exposure light are k _1A , k _2A , and k _3A , respectively. , K _1A <k _2A and k _2A > k _3A . By doing so, a function of transmitting the exposure light of the ArF excimer laser at a predetermined transmittance (2% or more) and a function of generating a predetermined phase difference with respect to the exposure light of the ArF excimer laser transmitted therethrough. Further, the reflectance (phase shift) of the exposure light transmitted through the inside of the light transmitting substrate 1 is reflected by the light reflected at the interface between the light transmitting substrate 1 (one main surface) and the phase shift film 2. The present inventor has found that the phase shift film 2 having a reduced reflectance on the back surface of the film 2 can be reduced, and stray light generated at the time of exposure to the phase shift mask can be suppressed. Thereby, it is possible to suppress the reflection of the barcode or the alignment mark provided outside the pattern formation region of the phase shift mask on the transfer target, which is caused by the stray light.

Also, as in the present embodiment, in the phase shift film 2 including the fourth A layer 24, when the refractive index of the fourth A layer 24 at the wavelength of the exposure light of the ArF excimer laser is n _4A , n _1A > n _4A And the relationship of n _3A > n _4A is satisfied, and the relationship of k _1A > k _4A and the relationship of k _3A > k _4A are satisfied when the extinction coefficient of the fourth A layer 24 at the wavelength of the exposure light of the ArF excimer laser is k _4. Preferably, it is It is more preferable that the relationship of n _2A > n _4A is satisfied. Although the phase shift film 2 of the present embodiment is configured to include the fourth A layer 24, the phase shift film 2 that satisfies the above-described conditions of the transmittance and the phase difference may include the fourth A layer 24. Is not required.

In addition, the refractive index n _1A of the first A layer 21 is preferably 2.0 or more, and more preferably 2.1 or more. The refractive index n1 of the _{first A} layer 21 is preferably 3.0 or less, more preferably 2.8 or less. The extinction coefficient k _1A of the first A layer 21 is preferably 0.5 or less, and more preferably 0.4 or less. Further, the extinction coefficient k _1A of the first A layer 21 is preferably 0.1 or more, and more preferably 0.2 or more.

The refractive index _{n 2A} of the 2A layer 22 is preferably less than 2.0, more preferably a 1.9 or less. The refractive index _{n 2A} of the 2A layer 22 is preferable to be 1.0 or more, and more preferably 1.2 or more. Further, the extinction coefficient k _2A of the second A layer 22 is preferably 1.0 or more, and more preferably 1.2 or more. Further, the extinction coefficient k _2A of the second A layer 22 is preferably 2.2 or less, and more preferably 2.0 or less.
In order for the phase shift film 2 to satisfy the above conditions, the refractive index n _3A of the third A layer 23 is preferably 2.0 or more, and more preferably 2.1 or more. Further, the refractive index n _3A of the third A layer 23 is preferably 3.0 or less, more preferably 2.8 or less. The extinction coefficient k _3A of the third A layer 23 is preferably 0.5 or less, and more preferably 0.4 or less. Further, the extinction coefficient _{k 3A} of the 3A layer 23 is preferable to be 0.1 or more, and more preferably 0.2 or more.
The 4A layer 24 preferably has a refractive index n _4A of 1.8 or less, more preferably 1.7 or less. In addition, the fourth A layer 24 preferably has a refractive index n _4A of 1.5 or more, more preferably 1.55 or more. On the other hand, the fourth A layer 24 preferably has an extinction coefficient k _4A of 0.1 or less, more preferably 0.05 or less.

In order for the phase shift film 2 to satisfy the above conditions, in addition to the optical characteristics of the first A layer 21, the second A layer 22, and the third A layer 23, the first A layer 21, the second A layer 22, and the third A layer 23 When the film thicknesses are d _1A , d _2A , and d _3A respectively, it is at least necessary to satisfy the relations d _1A <d _3A and d _2A <d _3A .

The ratio of the first A layer 21 that contributes to the adjustment of the back surface reflectance of the phase shift film 2 is higher than that of the other two layers. Further, the ratio of the second A layer 22 that contributes to the adjustment of the transmittance of the phase shift film 2 is higher than that of the other two layers. Therefore, the degree of freedom in designing the thickness of the first A layer 21 and the second A layer 22 is relatively narrow. The third A layer 23 is required to contribute to the adjustment for the phase shift film 2 to have the required predetermined phase difference, and is desirably thicker than the other two layers. The thickness d _3A of the third A layer 23 is preferably at least twice the thickness d _1A of the first A layer 21, more preferably at least 2.2 times, and more preferably at least 2.5 times. preferable. Further, the thickness d _3A of the third A layer 23 is more preferably 5 times or less the thickness d _1A of the first A layer 21.

Thickness _{d 1A} of the 1A layer 21 is preferable to be 20nm or less, and more preferably less 18 nm. Further, the thickness d _1A of the first A layer 21 is preferably 3 nm or more, more preferably 5 nm or more.

Thickness _{d 2A} of the 2A layer 22 is preferable to be 20nm or less, and more preferably less 18 nm. The thickness _{d 2A} of the 2A layer 22 is preferably 2nm or more, and more preferably 3nm or more.
Preferably the film thickness _{d 3A} of the 3A layer 23 is 60nm or less, more preferably 50nm or less. The thickness _{d 3A} of the 3A layer 23 is preferably larger than 20 nm, more preferably a 25nm or more.
Thickness _{d 4A} of the 4A layer 24 is preferable to be 15nm or less, more preferably 10nm or less. The thickness _{d 4A} of the 4A layer 24 is preferably 1nm or more, and more preferably 2nm or more.

The first A layer 21, the second A layer 22, and the third A layer 23 are formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements and silicon and nitrogen. Preferably. Among these metalloid elements, it is preferable to include one or more elements selected from boron, germanium, antimony, and tellurium because the conductivity of silicon used as a sputtering target can be expected to be increased. In addition, it is preferable to include one or more elements selected from nitrogen, carbon, fluorine, and hydrogen among the nonmetallic elements. The non-metallic elements also include noble gases such as helium (He), argon (Ar), krypton (Kr), and xenon (Xe).
The fourth A layer 24 is preferably formed of a material composed of silicon and oxygen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and oxygen. By forming the fourth A layer 24 with such a material, it is possible to suppress the occurrence of haze that is likely to occur in a silicon-containing film having a high nitrogen content.

  The second A layer 22 preferably has a lower nitrogen content than any of the first A layer 21 and the third A layer 23. The nitrogen content in the material forming the second A layer 22 is preferably 40 atomic% or less, and more preferably 35 atomic% or less. The second A layer 22 needs to contribute to the transmittance of the phase shift film 2, but in order to increase both the difference in the refractive index and the difference in the extinction coefficient between the first A layer 21 and the third A layer 23, This is because it is preferable to suppress the nitrogen content that causes a rise in the refractive index and a decrease in the extinction coefficient. Further, the nitrogen content in the material forming the second A layer 22 is preferably 10 atomic% or more, and more preferably 15 atomic% or more. If the nitrogen content is small, the extinction coefficient of the second A layer 22 is increased, and the transmittance for exposure light is greatly reduced.

The first A layer 21 and the third A layer 23 are preferably at least 50 atomic%, more preferably at least 55 atomic%, and are composed of a stoichiometrically stable material, Si ₃ N ₄ . Is more preferable. The first A layer and the third A layer are preferably formed of a material having a high refractive index, because the refractive index can be increased by increasing the nitrogen content.

  The oxygen content of the fourth A layer 24 is preferably larger than each oxygen content of the first A layer 21, the second A layer 22, and the third A layer 23. The oxygen content of the fourth A layer 24 is preferably at least 50 atomic%, more preferably at least 55 atomic%.

  The first A layer 21 is preferably provided in contact with the surface of the translucent substrate 1. When the first A layer 21 is in contact with the surface of the light-transmitting substrate 1, the phase shift film 2 formed by the laminated structure of the first A layer 21, the second A layer, and the third A layer 23 of the phase shift film 2 is formed. This is because the effect of reducing the back surface reflectivity of the substrate can be further obtained. An etching stopper film may be provided between the translucent substrate 1 and the phase shift film 2 as long as the effect on the effect of reducing the back surface reflectance of the phase shift film 2 is small. In this case, the thickness of the etching stopper film needs to be 10 nm or less, preferably 7 nm or less, and more preferably 5 nm or less. Further, from the viewpoint of functioning effectively as an etching stopper, the thickness of the etching stopper film needs to be 3 nm or more. The extinction coefficient k of the material forming the etching stopper film needs to be less than 0.1, and is preferably 0.05 or less, more preferably 0.01 or less. Further, in this case, the refractive index n of the material forming the etching stopper film needs to be at least 1.9 or less, and is preferably 1.7 or less. The material forming the etching stopper film preferably has a refractive index n of 1.55 or more. Further, it is preferable that the etching stopper film is formed of a material containing silicon, aluminum and oxygen. Further, another thin film may be formed of a material containing hafnium and oxygen.

  It is preferable that the material for forming the first A layer 21 and the second A layer 22 and the material for forming the third A layer 23 except for the oxidized surface layer are both formed of the same element. The first A layer 21, the second A layer 22, and the third A layer 23 are patterned by dry etching using the same etching gas. Therefore, the first A layer 21, the second A layer 22, and the third A layer 23 are desirably etched in the same etching chamber. If the elements constituting the first A layer 21, the second A layer 22, and the third A layer 23 are the same, dry etching is performed on the first A layer 21, the second A layer 22, and the third A layer 23. An environmental change in the etching chamber when an object changes can be reduced.

  The first A layer 21, the second A layer 22, and the third A layer 23 in the phase shift film 2 are formed by sputtering, but any sputtering such as DC sputtering, RF sputtering, and ion beam sputtering can be applied. Considering the film formation rate, it is preferable to apply DC sputtering. In the case of using a target with low conductivity, it is preferable to apply RF sputtering or ion beam sputtering; however, in consideration of a film formation rate, it is more preferable to apply RF sputtering.

  The mask blank 110 includes the light shielding film 3 on the phase shift film 2. Usually, in the peripheral region of the transfer mask including the phase shift mask, the OD is preferably 2.7 or more. The phase shift film 2 has a function of transmitting exposure light at a predetermined transmittance, and it is difficult to secure a predetermined value of optical density using only the phase shift film 2. For this reason, it is necessary to stack the light shielding film 3 on the phase shift film 2 at the stage of manufacturing the mask blank 110 in order to secure an insufficient optical density. With such a configuration of the mask blank 110, the light-shielding film 3 in a region where the phase shift effect is used (basically, a transfer pattern forming region) is removed in the course of manufacturing the phase shift mask 210 (see FIG. 5). By doing so, it is possible to manufacture the phase shift mask 210 in which the optical density of the predetermined value is secured in the outer peripheral region.

  As the light-shielding film 3, any of a single-layer structure and a laminated structure of two or more layers can be applied. Each layer of the light-shielding film 3 having a single-layer structure and the light-shielding film 3 having a laminated structure of two or more layers has the same composition in the thickness direction of the film or the layer, but has the same composition in the thickness direction of the layer. The configuration may be inclined.

  The mask blank 110 in the embodiment shown in FIG. 2 has a configuration in which the light shielding film 3 is stacked on the phase shift film 2 without any other film. For the light shielding film 3 in this configuration, it is necessary to apply a material having a sufficient etching selectivity to an etching gas used when forming a pattern on the phase shift film 2. The light-shielding film 3 of the present embodiment is preferably formed of a material containing chromium. Examples of the material containing chromium that forms the light-shielding film 3 include, in addition to chromium metal, a material containing chromium and one or more elements selected from oxygen, nitrogen, carbon, boron, and fluorine. The material of the light-shielding film 3 may include a noble gas such as helium (He), argon (Ar), krypton (Kr), and xenon (Xe). Specifically, for example, materials such as CrN, CrON, CrOC, and CrOCN are exemplified.

  Generally, a chromium-based material is etched with a mixed gas of a chlorine-based gas and an oxygen gas, and chromium metal does not have a very high etching rate with respect to this etching gas. Considering that the etching rate of the mixed gas of the chlorine-based gas and the oxygen gas with respect to the etching gas is increased, the material for forming the light-shielding film 3 may be chromium containing one or more elements selected from oxygen, nitrogen, carbon, boron and fluorine. Is preferable. Further, the chromium-containing material forming the light-shielding film 3 may contain one or more elements of molybdenum, indium, and tin. By containing at least one of molybdenum, indium, and tin, the etching rate for a mixed gas of a chlorine-based gas and an oxygen gas can be further increased.

  Further, the light-shielding film 3 may be formed of a material containing a transition metal and silicon as long as etching selectivity for dry etching can be obtained with the material forming the fourth A layer 24 (particularly, the surface layer portion). . This is because a material containing a transition metal and silicon has a high light-shielding performance, and the thickness of the light-shielding film 3 can be reduced. The transition metal contained in the light shielding film 3 includes molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), chromium (Cr), hafnium (Hf), nickel (Ni), and vanadium (V). , Zirconium (Zr), ruthenium (Ru), rhodium (Rh), zinc (Zn), niobium (Nb), palladium (Pd), and the like, or alloys of these metals. Examples of the metal element other than the transition metal element contained in the light shielding film 3 include aluminum (Al), indium (In), tin (Sn), gallium (Ga), and the like.

  On the other hand, as a mask blank 110 of another embodiment, a light-shielding film 3 having a structure in which a layer made of a material containing chromium and a layer made of a material containing a transition metal and silicon are stacked in this order from the phase shift film 2 side is provided. You may. The specific matters of the material containing chromium and the material containing transition metal and silicon in this case are the same as in the case of the light shielding film 3 described above.

  In the mask blank 110, it is preferable that a hard mask film 4 formed of a material having an etching selectivity to an etching gas used when etching the light shielding film 3 is further laminated on the light shielding film 3. Since the hard mask film 4 is basically not restricted by the optical density, the thickness of the hard mask film 4 can be made much smaller than the thickness of the light shielding film 3. The resist film of the organic material is sufficient if it has a thickness enough to function as an etching mask until the dry etching for forming a pattern on the hard mask film 4 is completed. The thickness can be greatly reduced. Thinning the resist film is effective in improving the resolution of the resist and preventing pattern collapse, and is extremely important in meeting the demand for miniaturization.

When the light shielding film 3 is formed of a material containing chromium, the hard mask film 4 is preferably formed of a material containing silicon. Since the hard mask film 4 in this case tends to have low adhesion to the organic material resist film, the surface of the hard mask film 4 is subjected to HMDS (Hexamethyldisilazane) treatment to improve the surface adhesion. Is preferred. It is more preferable that the hard mask film 4 in this case is formed of SiO ₂ , SiN, SiON, or the like.

  In addition, as the material of the hard mask film 4 in the case where the light-shielding film 3 is formed of a material containing chromium, a material containing tantalum can be applied in addition to the above. In this case, the material containing tantalum includes, in addition to tantalum metal, a material in which tantalum contains one or more elements selected from nitrogen, oxygen, boron and carbon. For example, Ta, TaN, TaO, TaON, TaBN, TaBO, TaBON, TaCN, TaCO, TaCON, TaBCN, TaBOCN and the like can be mentioned. When the light-shielding film 3 is formed of a material containing silicon, the hard mask film 4 is preferably formed of the material containing chromium.

  The mask blank 110 of the present embodiment has the above-described configuration, and has a function of transmitting exposure light of an ArF excimer laser at a predetermined transmittance (2% or more), and a function of the light-transmitting substrate 1. And the function of reducing the back surface reflectance of the phase shift film 2 can be provided. Then, stray light generated at the time of exposing the phase shift mask 210 to be described later can be suppressed, and reflection of a barcode or an alignment mark caused by the stray light can be suppressed.

  FIG. 3 is a cross-sectional view illustrating a configuration of a mask blank 120 according to the third embodiment of the present invention. The mask blank 120 according to the present embodiment has a structure in which a pattern forming thin film 2 functioning as a phase shift film, a light shielding film 3 and a hard mask film 4 are stacked in this order on a light transmitting substrate 1 (this embodiment). In the description, the “pattern forming thin film 2” will be appropriately referred to as “phase shift film 2”.) The phase shift film 2 has a structure in which a first B layer 21, a second B layer 22, and a third B layer 23 are stacked from the light transmitting substrate 1 side. Note that the configurations of the light-transmitting substrate 1, the light-shielding film 3, the hard mask film 4, and the anti-reflection film 7 are the same as those described in the second embodiment, and a description thereof is omitted.

  The phase shift film 2 of the present embodiment has a function of transmitting the exposure light at a transmittance of 15% or more, and a function of transmitting the exposure light transmitted through the phase shift film 2 in air by the same distance as the thickness of the phase shift film 2. And a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the transmitted exposure light. It is preferable that the transmittance of the phase shift film 2 for the exposure light be 16% or more. On the other hand, the transmittance of the phase shift film 2 for exposure light is preferably 40% or less, more preferably 36% or less.

  The lower limit of the phase difference in the phase shift film 2 is preferably 155 degrees or more, and more preferably 160 degrees or more. On the other hand, the upper limit of the phase difference in the phase shift film 2 is preferably 190 degrees or less.

The phase shift film 2 has a structure in which a first B layer 21 and a second B layer 22 are stacked from the light transmitting substrate 1 side. The phase shift film 2 satisfies the relationship of n _1B <n _2B , where the refractive indexes of the first B layer 21 and the second B layer 22 at the wavelength of the exposure light of the ArF excimer laser are n _1B and n _2B , respectively. When the extinction coefficients at the wavelength of the exposure light of the first B layer 21 and the second B layer 22 are k _1B and k _2B , respectively, the relationship of k _1B <k _2B is satisfied. By doing so, a function of transmitting the exposure light of the ArF excimer laser at a predetermined transmittance (15% or more) and a function of generating a predetermined phase difference with respect to the exposure light of the ArF excimer laser transmitting the exposure light. In addition, the phase shift film 2 can be a phase shift film 2 in which the reflectance on the back surface of the phase shift film 2 is also reduced, and stray light generated at the time of exposure to the phase shift mask can be suppressed. The present inventor has found that the interference can be suppressed.
Further, as in the present embodiment, in the phase shift film 2 including the third B layer 23, when the refractive index of the third B layer 23 at the wavelength of the exposure light of the ArF excimer laser is n _3B , n _3B <n _1B When the extinction coefficient at the wavelength of the exposure light of the ArF excimer laser of the 3B layer 23 is k _3B , the relationship k _3B <k _1B is preferably satisfied. Although the phase shift film 2 of the present embodiment is configured to include the third B layer 23, the phase shift film 2 that satisfies the above-described conditions of the transmittance and the phase difference may include the third B layer 23. Is not required.

In addition, the refractive index n _1B of the first B layer 21 is preferably 1.8 or more, and more preferably 1.85 or more. Further, the refractive index n _1B of the first B layer 21 is preferably less than 2.2, and more preferably 2.15 or less. The extinction coefficient k _1B of the first B layer 21 is preferably 0.15 or less, and more preferably 0.14 or less. The extinction coefficient k _1B of the first B layer 21 is preferably equal to or greater than 0.05, and more preferably equal to or greater than 0.06.

Further, the refractive index n _2B of the second B layer 22 is preferably 2.2 or more, more preferably 2.25 or more. The refractive index _{n 2B} of the 2B layer 22 is preferable to be 3.0 or less, more preferably 2.8 or less. Further, the extinction coefficient k _2B of the second B layer 22 is preferably 0.2 or more, and more preferably 0.25 or more. Further, the extinction coefficient k _2B of the second B layer 22 is preferably 0.5 or less, and more preferably 0.4 or less.
The refractive index n _3B of the third B layer 23 is preferably 1.7 or less, and more preferably 1.65 or less. Further, the refractive index n _3B of the third B layer 23 is preferably 1.50 or more, and more preferably 1.52 or more. Extinction coefficient _{k 3B} of the 3B layer 23 is preferably 0.02 or less, more preferably 0.01 or less. Further, the extinction coefficient _{k 3B} of the 3B layer 23 is more preferably a 0.00 or more.

In order for the phase shift film 2 to satisfy the above conditions, in addition to the optical characteristics of the first B layer 21 and the second B layer 22, the thicknesses of the first B layer 21 and the second B layer 22 are d _1B and d _2B , respectively. At least, it is necessary to satisfy the relationship of d _1B <d _2B . When the thickness of the third layer 23 is d _3B , it is preferable that the relationship d _3B <d _1B is satisfied.

The thickness d _1B of the first B layer 21 is preferably less than 33 nm, and more preferably 32 nm or less. Further, the thickness d _1B of the first B layer 21 is preferably larger than 10 nm, and more preferably 15 nm or more.
Thickness _{d 2B} of the 2B layer 22 is preferable to be more than 33 nm, and more preferably is not less than 34 nm. The thickness _{d 2B} of the 2B layer 22 is preferably 50nm or less, more preferably below 48 nm.
Preferably the film thickness _{d 3B} of the 3B layer 23 is 30nm or less, more preferably 25nm or less. The thickness d _3B of the third B layer 23 is preferably 2 nm or more, and more preferably 3 nm or more.

The first B layer 21 is preferably formed of a material composed of silicon, nitrogen and oxygen, or a material composed of one or more elements selected from semimetal elements and nonmetal elements, silicon, nitrogen and oxygen. Further, the second B layer 22 is preferably formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and nitrogen.
The third B layer 23 is preferably formed of a material composed of silicon and oxygen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and oxygen. It is preferable that the oxygen content of the third B layer 23 be larger than the oxygen content of the first B layer 21. The oxygen content of the third B layer 23 is preferably at least 50 atomic%, more preferably at most 55 atomic%. By forming the 3B layer 23 with such a material, it is possible to suppress the occurrence of haze which is likely to occur in a silicon-containing film having a high nitrogen content.
Preferred semimetal elements and nonmetal elements in each layer of the phase shift film 2 of the present embodiment are as described in the second embodiment.

  The second B layer 22 preferably has a higher nitrogen content than the first B layer 21. The nitrogen content of the first B layer 21 is preferably at most 40 atomic%, more preferably at most 30 atomic%. Further, the nitrogen content of the first B layer 21 is preferably at least 10 atomic%, more preferably at least 15 atomic%. This is because, in order to increase the difference in the refractive index from the second B layer 21, it is preferable to suppress the nitrogen content that causes the increase in the refractive index. Although the extinction coefficient of the second B layer 21 is reduced by suppressing the nitrogen content, the extinction coefficient of the second B layer 21 can be increased by increasing the oxygen content, and the transmission of the entire phase shift film 2 can be improved. The ratio can be easily adjusted to 15% or more.

  On the other hand, the nitrogen content of the second B layer 22 is preferably 45 atomic% or more, more preferably 50 atomic% or more, and further preferably 55 atomic% or more. The second B layer 22 is preferably formed of a material having a high refractive index, because the refractive index can be increased by increasing the nitrogen content.

  The first B layer 21 is preferably provided in contact with the surface of the translucent substrate 1. When the first B layer 21 is configured to be in contact with the surface of the translucent substrate 1, the phase shift film 2 formed by the laminated structure of the first B layer 21, the second B layer, and the third B layer 23 of the phase shift film 2 is used. This is because the effect of reducing the back surface reflectivity of the substrate can be further obtained. If the effect on the effect of reducing the back surface reflectance of the phase shift film 2 is small, an etching stopper film may be provided between the translucent substrate 1 and the phase shift film 2 as in the second embodiment. Good.

It is preferable that the oxygen content of the first B layer 21 be larger than the oxygen content of the second B layer 22. The oxygen content of the first B layer 21 is preferably at least 10 atomic%, more preferably at least 15 atomic%. Further, the oxygen content of the first B layer 21 is preferably 45 atomic% or less, more preferably 40 atomic% or less. On the other hand, the oxygen content of the second B layer 22 is preferably 5 atomic% or less, more preferably 2 atomic% or less. More preferably, the second B layer 22 does not contain oxygen. This is because the refractive index of the second B layer 22 decreases as the oxygen content of the second B layer 22 increases.
It is preferable that the oxygen content of the third B layer 23 be larger than the oxygen content of the first B layer 21. The oxygen content of the third B layer 23 is preferably at least 50 atomic%, more preferably at least 55 atomic%.

  The mask blank 120 of the present embodiment has the above-described configuration, and has a function of transmitting exposure light of an ArF excimer laser at a predetermined transmittance (15% or more) and a function of transmitting the light-transmitting substrate 1. And the function of reducing the back surface reflectance of the phase shift film 2 can be provided. Then, stray light generated at the time of exposing the phase shift mask 220, which will be described later, can be suppressed, and reflection of a barcode or an alignment mark caused by the stray light can be suppressed.

  In each embodiment, a mask blank (mask blank 100) for a chromeless phase shift mask and a mask blank (mask blanks 110 and 120) for a halftone type phase shift mask have been described. The present invention is not limited to these, and can be used, for example, as a mask blank for a binary mask or a mask blank for manufacturing a dug Levenson-type phase shift mask.

Next, a method for manufacturing a phase shift mask (transfer mask) using the mask blank 100 of the first embodiment will be described.
FIG. 4 shows a phase shift mask (transfer mask) 200 according to the first embodiment of the present invention manufactured from the mask blank 100 of the first embodiment, and a manufacturing process thereof. As shown in FIG. 4G, the phase shift mask 200 is a digging type phase shift mask in which a phase shift pattern 1 a as a transfer pattern is formed on the translucent substrate 1 of the mask blank 100. (Chromeless phase shift mask).

  First, a resist film is formed in contact with the hard mask film 4 in the mask blank 100 by a spin coating method. Next, a first pattern corresponding to the transfer pattern dug into the translucent substrate 1 is exposed and drawn on the resist film with an electron beam, and further subjected to a predetermined process such as a developing process. 5a is formed (see FIG. 4A). Subsequently, using the first resist pattern 5a as a mask, dry etching is performed using a mixed gas of a chlorine-based gas and an oxygen-based gas to form a first pattern (hard mask pattern 4a) on the hard mask film 4. (See FIG. 4B).

  Next, after the first resist pattern 5a is removed, dry etching using a fluorine-based gas is performed using the hard mask pattern 4a as a mask to form a first pattern (light shielding pattern 3a) on the light shielding film 3. (See FIG. 4 (c)). Subsequently, dry etching using a mixed gas of a chlorine-based gas and an oxygen-based gas is performed using the light-shielding pattern 3a as a mask to form a first pattern (etching stopper film pattern 2a) on the hard mask film 2 serving as an etching stopper. Then, the hard mask pattern 4a is removed (see FIG. 4D).

  Next, a resist film is formed on the entire surface of the mask blank 100 on which the light-shielding pattern 3a is formed by the spin coating method in the same manner as described above. The resist film is exposed and drawn with a second pattern, which is a pattern (a light-shielding band pattern) to be formed on the light-shielding film 3, with an electron beam, and further subjected to a predetermined process such as a development process. 6b is formed (see FIG. 4E). Subsequently, using the second resist pattern 6b as a mask, dry etching using a fluorine-based gas is performed to peel off and remove the exposed light-shielding pattern 3a of the light-shielding film 3, and to form the etching stopper and the hard mask film 2 as well. By using the etched stopper film pattern 2a as a mask, the light-transmitting substrate 1 is dry-etched to form a phase-shift pattern 1a of a substrate digging type (see FIG. 4F). As a dry etching gas, a mixed gas of a fluorine-based gas and helium is used.

Next, using the light-shielding pattern 3b as a mask, the exposed etching stopper film pattern 2a is peeled off by dry etching using a mixed gas of chlorine gas and oxygen gas, and the remaining resist pattern 6b is removed ( FIG. 5 (g)).
As described above, the digging type phase shift pattern 1a is formed on the translucent substrate 1, and the digging type phase shift mask (transfer mask) provided with the light shielding pattern (light shielding band pattern) in the outer peripheral region. ) 200 can be completed.

The chlorine-based gas used in the dry etching is not particularly limited as long as it contains Cl. For example, Cl ₂ , SiCl ₂ , CHCl ₃ , CH ₂ Cl ₂ , CCl ₄ , BCl _{3 and the} like can be mentioned. The fluorine-based gas used in the dry etching is not particularly limited as long as F is contained. For example, CHF ₃ , CF ₄ , C ₂ F ₆ , C ₄ F ₈ , SF _{6 and the} like can be mentioned. In particular, a fluorine-based gas containing no C has a relatively low etching rate with respect to a glass substrate, so that damage to the glass substrate can be further reduced.

The phase shift mask 200 of the present invention is manufactured using the mask blank 100 described above, and the transfer pattern is provided on the translucent substrate 1 of the mask blank 100. Therefore, it is possible to manufacture the phase shift mask 200 having a function of transmitting the exposure light of the ArF excimer laser at a predetermined transmittance and a function of reducing the rear surface reflectance of the light transmitting substrate.
Further, according to the method for manufacturing a semiconductor device including a step of exposing and transferring a transfer pattern to a resist film on a semiconductor substrate using the phase shift mask 200 manufactured from the mask blank 100 of the present embodiment, It is possible to manufacture a high-quality semiconductor device on which a highly accurate device pattern is formed.

  FIG. 5 shows phase shift masks (transfer masks) 210 and 220 according to the second and third embodiments of the present invention manufactured from the mask blanks 110 and 120 according to the second and third embodiments, and manufacturing steps thereof. Is shown. As shown in FIG. 5G, the phase shift masks 210 and 220 have a phase shift pattern 2 a as a transfer pattern formed on the phase shift film 2 of the mask blanks 110 and 120, and a light shielding pattern 3 on the light shielding film 3. 3c is formed. In the case of a configuration in which the hard mask film 4 is provided on the mask blanks 110 and 120, the hard mask film 4 is removed during the production of the phase shift masks 210 and 220.

  The method of manufacturing the phase shift masks 210 and 220 according to the second and third embodiments of the present invention uses the mask blanks 110 and 120, and forms a transfer pattern on the light shielding film 3 by dry etching. Forming a transfer pattern on the phase shift film 2 by dry etching using the light-shielding film 3 having the transfer pattern as a mask, and dry etching using the resist film (second resist pattern) 6c having the light-shielding pattern as a mask Forming a light-shielding pattern 3 c on the light-shielding film 3. Hereinafter, a method of manufacturing the phase shift masks 210 and 220 according to the present invention will be described according to the manufacturing process illustrated in FIG. Here, a method of manufacturing the phase shift masks 210 and 220 using the mask blanks 110 and 120 in which the hard mask film 4 is laminated on the light shielding film 3 will be described. The case where a material containing chromium is applied to the light-shielding film 3 and a material containing silicon is applied to the hard mask film 4 will be described.

  First, a resist film is formed by spin coating in contact with the hard mask film 4 in the mask blanks 110 and 120. Next, a first pattern which is a transfer pattern (phase shift pattern) to be formed on the phase shift film 2 is exposed and drawn on the resist film with an electron beam, and further subjected to a predetermined process such as a development process. A first resist pattern 5a having a shift pattern was formed (see FIG. 5A). Subsequently, using the first resist pattern 5a as a mask, dry etching using a fluorine-based gas was performed to form a first pattern (hard mask pattern 4a) on the hard mask film 4 (see FIG. 5B). .

  Next, after removing the resist pattern 5a, dry etching using a mixed gas of a chlorine-based gas and an oxygen gas is performed using the hard mask pattern 4a as a mask to form a first pattern (light-shielding pattern 3a) on the light-shielding film 3. Is formed (see FIG. 5C). Subsequently, dry etching using a fluorine-based gas is performed using the light-shielding pattern 3a as a mask to form a first pattern (phase shift pattern 2a) on the phase shift film 2 and remove the hard mask pattern 4a (FIG. 5 (d)).

  Next, a resist film was formed on the mask blanks 100 and 110 by a spin coating method. Next, a second pattern, which is a pattern (light-shielding pattern) to be formed on the light-shielding film 3, is exposed and drawn on the resist film with an electron beam, and further subjected to a predetermined process such as a development process to provide a light-shielding pattern. A second resist pattern 6c was formed (see FIG. 5E). Subsequently, using the second resist pattern 6c as a mask, dry etching is performed using a mixed gas of a chlorine-based gas and an oxygen gas to form a second pattern (light-shielding pattern 3c) on the light-shielding film 3 (FIG. 5 ( f)). Further, the second resist pattern 6c was removed, and the phase shift masks 210 and 220 were obtained through predetermined processing such as cleaning (see FIG. 5G).

  The chlorine-based gas and the fluorine-based gas used in the dry etching are the same as those in the manufacturing process of the phase shift mask 200 according to the first embodiment.

  The phase shift masks 210 and 220 of the present invention are manufactured using the mask blanks 110 and 120 described above. For this reason, the phase shift film 2 (phase shift pattern 2a) on which the transfer pattern is formed has a transmittance of 2% or more or 15% or more to the exposure light of the ArF excimer laser, and the exposure light transmitted through the phase shift pattern 2a. And the exposure light that has passed through the air by the same distance as the thickness of the phase shift pattern 2a is in the range of 150 degrees or more and 200 degrees or less. Further, in the phase shift masks 210 and 220, the back surface reflectance of the phase shift pattern 2a is reduced, and the back surface reflectance of the translucent substrate 1 is also reduced. Thus, when exposure transfer is performed on a transfer target (a resist film on a semiconductor wafer or the like) using the phase shift mask 200, the influence of the stray light on the exposure transfer image can be suppressed.

  The method of manufacturing a semiconductor device according to the present invention is characterized in that a transfer pattern is exposed and transferred to a resist film on a semiconductor substrate using the phase shift masks 210 and 220 described above. The phase shift masks 210 and 220 have both a function of transmitting the ArF excimer laser exposure light at a predetermined transmittance and a function of generating a predetermined phase difference with respect to the transmitted ArF excimer laser exposure light. The rear surface reflectance of the shift pattern 2a is greatly reduced as compared with the conventional one, and the rear surface reflectance of the light transmitting substrate 1 is also reduced. For this reason, the phase shift masks 210 and 220 are set in an exposure apparatus, and exposure light of an ArF excimer laser is irradiated from the transparent substrate 1 side of the phase shift masks 210 and 220 to transfer an object to be transferred (on a semiconductor wafer). Even if a step of exposing and transferring to a resist film is performed, it is possible to suppress the reflection of the barcode and the alignment mark formed on the phase shift masks 210 and 220 on the transfer target, and to transfer the barcode and the alignment mark onto the transfer target with high accuracy. A desired pattern can be transferred.

Hereinafter, embodiments of the present invention will be described more specifically with reference to examples.
(Example 1)
[Manufacture of mask blanks]
A translucent substrate 1 made of synthetic quartz glass having a main surface dimension of about 152 mm × about 152 mm and a thickness of about 6.35 mm was prepared. The light-transmitting substrate 1 has an end face and a main surface polished to a predetermined surface roughness, and then subjected to a predetermined cleaning process and a drying process. The optical properties of the transparent substrate 1 was measured, the refractive index _{n S} is 1.556, extinction coefficient _{k S} was 0.00.

Next, the main surface of the light transmitting substrate 1 is subjected to reactive sputtering in a mixed gas atmosphere of argon (Ar), carbon dioxide (CO ₂ ), and helium (He) using a target made of chromium. On the (one main surface), an etching stopper / hard mask film 2 made of a CrOC film containing chromium, oxygen and carbon was formed with a thickness of 10 nm.

Next, the translucent substrate 1 on which the etching stopper and the hard mask film 2 are formed is placed in a single-wafer RF sputtering apparatus, and nitrogen (N ₂ ), argon (Ar) and A mixed gas of helium (He) (flow ratio: Ar: N ₂ : He = 30: 3: 100) is used as a sputtering gas, and reactive sputtering (RF sputtering) using an RF power source is performed on the surface of the etching stopper / hard mask film 2. In contact therewith, a light-shielding film 3 made of a SiN film containing silicon and nitrogen (Si: 75.5 atomic%, N: 24.5 atomic%) was formed with a thickness of 47 nm. The optical density of the laminated film of the etching stopper / hard mask film 2 and the light shielding film 3 was 3.0 or more at the wavelength of ArF excimer laser (193 nm).

Next, the translucent substrate 1 on which the light-shielding film 3 is formed is placed in a single-wafer DC sputtering apparatus. Using a chromium target, argon (Ar), carbon dioxide (CO ₂ ), and helium ( By performing DC sputtering using a mixed gas of He) under the same film forming conditions as when forming the hard mask film 2 serving as an etching stopper, the surface of the light shielding film 3 is formed of a CrOC film containing chromium, oxygen, and carbon. The hard mask film 4 was formed with a thickness of 10 nm.

Next, the translucent substrate 1 is set in a single-wafer DC sputtering apparatus so that the back surface (the other main surface) of the translucent substrate 1 is exposed, and a silicon (Si) target is used, and argon (Ar) is used. ) And nitrogen (N ₂ ) as a sputtering gas, the first layer 71 (SiN) of the antireflection film 7 made of silicon and nitrogen is formed on the back surface of the translucent substrate 1 by reactive sputtering (RF sputtering). A film (Si: N = 68 atomic%: 32 atomic%) was formed with a thickness of 20 nm. Subsequently, silicon and nitrogen are formed on the first layer 71 by reactive sputtering (RF sputtering) using a mixed gas of argon (Ar) and nitrogen (N ₂ ) as a sputtering gas using a silicon (Si) target. The second layer 72 (SiN film Si: N = 43 atomic%: 57 atomic%) of the antireflection film 7 was formed with a thickness of 6 nm. Subsequently, silicon and oxygen are formed on the second layer 72 by reactive sputtering (RF sputtering) using a mixed gas of argon (Ar) and oxygen (O ₂ ) as a sputtering gas using a silicon (Si) target. The third layer 73 of the antireflection film 7 (SiO film Si: O = 33 atomic%: 67 atomic%) was formed with a thickness of 15 nm. According to the above procedure, the antireflection film 7 in which the first layer 71, the second layer 72, and the third layer 73 were stacked in contact with the back surface of the translucent substrate 1 was formed with a thickness of 41 nm.

  Note that the antireflection film 7 is a region for forming a transfer pattern set on the main surface (one main surface) of the translucent substrate 1 (a square inner region having a side of 132 mm with respect to the center of the substrate). Was not formed on the area of the other main surface corresponding to. Specifically, the first layer 21, the second layer 22, and the third layer 23 were formed by reactive sputtering with the other main surface in a region where the antireflection film 7 was not formed covered with a shielding member. The compositions of the first layer 21, the second layer 22, and the third layer 23 are the results obtained by measurement by X-ray photoelectron spectroscopy (XPS). Hereinafter, the same applies to other films.

Further, the wavelength of the exposure light of the ArF excimer laser of the antireflection film 7 was measured for another translucent substrate on which only the antireflection film 7 was formed using a phase shift amount measuring device (MPM193 manufactured by Lasertec). When the transmittance for light having a wavelength of 193 nm) was measured, the transmittance was 12.5%. When the optical characteristics of the first layer 71, the second layer 72, and the third layer 73 of the antireflection film 7 were measured with a spectral ellipsometer (M-2000D manufactured by JA Woollam), the first layer was measured. 71, the refractive index _{n 1} is 1.648, extinction coefficient _{k 1} is 1.861, the second layer 72 has a refractive index _{n 2} is 2.595, extinction coefficient _{k 2} is located at 0.357 , third layer 73 has a refractive index _{n 3} is 1.590, extinction coefficient _{k 3} it was 0.000. The back surface reflectance of the antireflection film 7 with respect to the light having the wavelength of the exposure light of the ArF excimer laser was 0.5%.

[Manufacture of phase shift mask]
Next, using the mask blank 100 of the first embodiment, the phase shift mask 200 of the first embodiment was manufactured in the following procedure. First, a chemically amplified resist for electron beam writing (PRL009, manufactured by Fuji Film Electronics Materials Co., Ltd.) is applied to the upper surface of the mask blank 100 by spin coating, and a predetermined baking process is performed to obtain a film having a thickness of 80 nm. A resist film was formed. Next, a predetermined device pattern (a pattern corresponding to a transfer pattern dug into the substrate) was drawn on the resist film using an electron beam drawing machine, and then the resist film was developed to form a resist pattern 5a. (See FIG. 4A). The resist pattern 5a includes a line-and-space pattern having a line width of 50 nm.

Next, using the resist pattern 5a as a mask, dry etching of the hard mask film 4 was performed by dry etching to form a pattern 4a on the hard mask film 4 (see FIG. 4B). As an etching gas, a mixed gas of chlorine gas (Cl ₂ ) and oxygen gas (O ₂ ) (Cl ₂ : O ₂ = 13: 1 (flow ratio)) is used, and the power when a bias voltage is applied is 50 W. Dry etching was performed.

Next, after removing the resist pattern 5a, the SiN-based light-shielding film 3 is dry-etched by using the pattern 4a of the hard mask film 4 as a mask and using a fluorine-based gas (SF ₆ ) as an etching gas. 3 was formed with a pattern 3a (see FIG. 4C).

Next, using the pattern 3a of the light shielding film 3 as a mask, dry etching of the etching stopper and the hard mask film 2 is performed by dry etching to form a pattern 2a on the etching stopper and the hard mask film 2, and the hard mask pattern 4a is formed. It was removed (see FIG. 4 (d)). As an etching gas, a mixed gas of chlorine gas (Cl ₂ ) and oxygen gas (O ₂ ) (Cl ₂ : O ₂ = 13: 1 (flow ratio)) is used, and the power when a bias voltage is applied is 50 W. Dry etching was performed.

  Next, a resist film similar to the above is formed on the entire surface of the mask blank on which the pattern 3a of the light-shielding film 3 is formed, and a predetermined light-shielding pattern (light-shielding band pattern) is drawn on the resist film. Then, a resist pattern 6b having a light-shielding pattern was formed by development (see FIG. 4E).

Next, by using the resist pattern 6b as a mask, the exposed pattern 3a of the light-shielding film 3 is removed by dry etching using a fluorine-based gas, and the etching stopper film formed on the etching stopper / hard mask film 2 is formed. Using the pattern 2a as a mask, the light-transmitting substrate 1 (synthetic quartz substrate) was dry-etched to form a substrate-digging type phase shift pattern 1a (see FIG. 4F). At this time, the substrate was dug to a depth (about 173 nm) at which a phase difference of 180 degrees was obtained. Note that a mixed gas of a fluorine-based gas (CF ₄ ) and helium (He) was used as an etching gas for dry etching.

Next, using the resist pattern 6b as a mask, the resist pattern 6b is exposed by dry etching using a mixed gas (Cl ₂ : O ₂ = 4: 1 (flow ratio)) of chlorine gas (Cl ₂ ) and oxygen gas (O ₂ ). The removed etching stopper film pattern 2a was removed and removed, and the remaining resist pattern 6b was removed (see FIG. 4G).

  As described above, the digging type phase shift pattern 1a is formed on the translucent substrate 1, and the digging type phase shift mask (transfer mask) provided with the light shielding pattern (light shielding band pattern) in the outer peripheral region. ) 200 was completed (see FIG. 4 (g)).

  As a result of inspecting the obtained phase shift mask 200 for a mask pattern by a mask inspection apparatus, it was confirmed that a phase shift pattern was formed within an allowable range from a design value.

(Example 2)
[Manufacture of mask blanks]
The mask blank 110 of Example 2 was manufactured in the same procedure as in Example 1 except for the phase shift film 2, the light shielding film 3, and the hard mask film 4.
Specifically, the light-transmitting substrate 1 is placed in a single-wafer RF sputtering apparatus, and an RF using a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) as a sputtering gas using a silicon (Si) target. By sputtering, the first A layer 21 (SiN film Si: N = 43 at%: 57 at%) of the phase shift film 2 made of silicon and nitrogen in contact with the surface (one main surface) of the translucent substrate 1 has a thickness of 12 nm. The thickness was formed. Subsequently, silicon and nitrogen are formed on the first A layer 21 by reactive sputtering (RF sputtering) using a silicon (Si) target and a mixed gas of argon (Ar) and nitrogen (N ₂ ) as a sputtering gas. The second A layer 22 (SiN film Si: N = 68 atomic%: 32 atomic%) of the phase shift film 2 was formed with a thickness of 15 nm. Subsequently, silicon and nitrogen are formed on the second A layer 22 by reactive sputtering (RF sputtering) using a silicon (Si) target and a mixed gas of argon (Ar) and nitrogen (N ₂ ) as a sputtering gas. The third A layer 23 (SiN film Si: N = 43 atomic%: 57 atomic%) of the phase shift film 2 was formed with a thickness of 42 nm. Subsequently, using a silicon (Si) target, a reactive gas (RF sputtering) using a mixed gas of argon (Ar) and oxygen (O ₂ ) as a sputtering gas is formed on the third A layer 23 from silicon and oxygen. The fourth A layer 24 of the phase shift film 2 (SiO film Si: O = 33 at%: 67 at%) was formed with a thickness of 3 nm. According to the above procedure, the phase shift film 2 in which the first A layer 21, the second A layer 22, the third A layer 23, and the fourth A layer 24 were stacked in contact with the surface of the translucent substrate 1 was formed with a thickness of 72 nm.

Next, the transmittance and the phase difference of the phase shift film 2 with respect to the light (wavelength 193 nm) of the exposure light of the ArF excimer laser were measured using a phase shift amount measuring device (MPM193 manufactured by Lasertec). The rate was 6.2% and the phase difference was 178.2 degrees (deg). In addition, each optical characteristic of the first A layer 21, the second A layer 22, the third A layer 23, and the fourth A layer 24 of the phase shift film 2 was measured with a spectral ellipsometer (M-2000D manufactured by JA Woollam). However, the first A layer 21 has a refractive index n _1A of 2.595 and an extinction coefficient k _1A of 0.357, and the second A layer 22 has a refractive index n _2A of 1.648 and an extinction coefficient k _2A of 1. 861, the third A layer 23 has a refractive index n _3A of 2.595 and an extinction coefficient k _3A of 0.357, and the fourth A layer 24 has a refractive index n _4A of 1.590 and an extinction coefficient of _k4A was 0.000. The back surface reflectance of the phase shift film 2 with respect to the light having the wavelength of the exposure light of the ArF excimer laser was 3.8%.

Next, the translucent substrate 1 on which the phase shift film 2 is formed is set in a single-wafer DC sputtering apparatus, and argon (Ar), carbon dioxide (CO ₂ ), nitrogen ( A light-shielding film 3 made of CrOCN (CrOCN film Cr: O: C: N = 55 atoms) on the phase shift film 2 by reactive sputtering (DC sputtering) using a mixed gas of N ₂ ) and helium (He) as a sputtering gas. %: 22 at%: 12 at%: 11 at%) with a thickness of 43 nm. When the phase shift film 2 and the light-shielding film 3 were laminated on the light-transmitting substrate 1, the back surface reflectance for light having the wavelength of the exposure light of the ArF excimer laser was 4.7%. When the optical density (OD) of the laminated structure of the phase shift film 2 and the light shielding film 3 with respect to light having a wavelength of 193 nm was measured, it was 3.0 or more. Further, another translucent substrate 1 was prepared, only the light-shielding film 3 was formed under the same film-forming conditions, and the optical characteristics of the light-shielding film 3 were measured by the above-mentioned spectral ellipsometer. 92, the extinction coefficient k was 1.50.

Next, the translucent substrate 1 on which the phase shift film 2 and the light-shielding film 3 are laminated is set in a single-wafer RF sputtering apparatus, and argon (Ar) gas is sputtered using a silicon dioxide (SiO ₂ ) target. Using a gas, a hard mask film 4 made of silicon and oxygen was formed on the light shielding film 3 by RF sputtering to a thickness of 5 nm.
Then, under the same film forming conditions as in Example 1, the antireflection film 7 in which the first layer 71, the second layer 72, and the third layer 73 are laminated on the back surface (the other main surface) of the translucent substrate 1 is formed. It was formed with a thickness of 41 nm.
According to the above procedure, a structure in which the phase shift film 2, the light-shielding film 3, and the hard mask film 4 having a four-layer structure are laminated on the surface of the light-transmitting substrate 1 is provided. A mask blank 110 including the antireflection film 7 having a layer structure was manufactured.
For this mask blank 110, the back surface reflectance was measured and found to be 0.0%. The back reflectance of the mask blank refers to the light emitted from the surface of the antireflection film 7 (the light reflected at the interface between the air and the antireflection film 7, the light reflected by the light transmitting substrate 1 and the phase shift film 2). This is the reflectance associated with the light combined at the interface and the like (the same applies to Example 3 and Comparative Example 1 below).

[Manufacture of phase shift mask]
Next, using the mask blank 110 of the second embodiment, the phase shift mask 210 of the second embodiment was manufactured in the following procedure. First, HMDS processing was performed on the surface of the hard mask film 4. Subsequently, a resist film made of a chemically amplified resist for electron beam writing was formed to a thickness of 80 nm in contact with the surface of the hard mask film 4 by spin coating. Next, a first pattern which is a phase shift pattern to be formed on the phase shift film 2 is drawn by an electron beam on the resist film, and a predetermined developing process and a cleaning process are performed. One resist pattern 5a was formed (see FIG. 5A). At this time, a pattern having a shape corresponding to a barcode or an alignment mark was also formed on the first resist pattern 5a outside the pattern formation region.

Next, using the first resist pattern 5a as a mask, dry etching using CF ₄ gas was performed to form a first pattern (hard mask pattern 4a) on the hard mask film 4 (see FIG. 5B). . At this time, a pattern having a shape corresponding to the bar code and the alignment mark was also formed on the hard mask film 4 outside the pattern formation region. After that, the first resist pattern 5a was removed.

Subsequently, using the hard mask pattern 4a as a mask, dry etching is performed using a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 10: 1), and the first pattern (light shielding pattern) is formed on the light shielding film 3. 3a) was formed (see FIG. 5C). At this time, a pattern having a shape corresponding to the barcode and the alignment mark was also formed on the light shielding film 3 outside the pattern formation region. Next, using the light shielding pattern 3a as a mask, dry etching using a fluorine-based gas (SF ₆ + He) is performed to form a first pattern (phase shift pattern 2a) on the phase shift film 2 and at the same time a hard mask pattern. 4a was removed (see FIG. 5D). At this time, a pattern having a shape corresponding to the barcode and the alignment mark was also formed on the phase shift film 2 outside the pattern formation region.

Next, a resist film made of a chemically amplified resist for electron beam lithography was formed to a thickness of 150 nm on the light-shielding pattern 3a by spin coating. Next, a second pattern, which is a pattern (light-shielding pattern) to be formed on the light-shielding film, is exposed and drawn on the resist film, and a predetermined process such as a developing process is performed. A pattern 6c was formed (see FIG. 5E). Subsequently, dry etching is performed using a mixed gas of chlorine and oxygen (gas flow ratio Cl ₂ : O ₂ = 4: 1) using the second resist pattern 6c as a mask, and the second pattern ( A light-shielding pattern 3c) was formed (see FIG. 5F). Further, the second resist pattern 6c was removed, and a predetermined process such as cleaning was performed to obtain a phase shift mask 210 (see FIG. 5G).

  Using the AIMS 193 (manufactured by Carl Zeiss), a simulation of an exposure transfer image when the phase shift mask 200 was exposed and transferred to a resist film on a semiconductor device with exposure light of an ArF excimer laser was performed. When the exposure transfer image obtained by this simulation was verified, the design specification was sufficiently satisfied. Further, in the exposure transfer image, no CD variation due to reflection of a barcode or an alignment mark was observed. From the above, the phase shift mask 210 manufactured from the mask blank of the second embodiment can be applied to the resist film on the semiconductor device even when the phase shift mask 210 is set in the exposure apparatus and subjected to exposure and transfer using the exposure light of the ArF excimer laser. It can be said that exposure transfer can be performed with high precision.

(Example 3)
[Manufacture of mask blanks]
The mask blank 120 of Example 3 was manufactured in the same procedure as Example 2 except for the phase shift film 2. The phase shift film 2 according to the third embodiment includes a first B layer 21, a second B layer 22, and a third B layer 23 having different thicknesses and compositions from those of the second embodiment. Specifically, the translucent substrate 1 is placed in a single-wafer RF sputtering apparatus, and a mixed gas of argon (Ar) gas, oxygen (O ₂ ) and nitrogen (N ₂ ) is used using a silicon (Si) target. The first B layer 21 of the phase shift film 2 made of silicon, oxygen and nitrogen (SiON film Si: O: N = 40 at.%: 35 at.) In contact with the surface of the translucent substrate 1 by RF sputtering using %: 25 atomic%) with a thickness of 29.5 nm. Subsequently, silicon and nitrogen are formed on the first B layer 21 by reactive sputtering (RF sputtering) using a mixed gas of argon (Ar) and nitrogen (N ₂ ) as a sputtering gas using a silicon (Si) target. The second B layer 22 (SiN film Si: N = 43 atomic%: 57 atomic%) of the phase shift film 2 was formed with a thickness of 41.5 nm. Subsequently, silicon and oxygen are formed on the second B layer 22 by reactive sputtering (RF sputtering) using a mixed gas of argon (Ar) and oxygen (O ₂ ) as a sputtering gas using a silicon (Si) target. The third B layer 23 of the phase shift film 2 (SiO film Si: O = 33 atomic%: 67 atomic%) was formed with a thickness of 3 nm. According to the above procedure, the phase shift film 2 in which the first B layer 21, the second B layer 22, and the third B layer 23 were stacked in contact with the surface of the translucent substrate 1 was formed with a thickness of 74 nm.

When the transmittance and the phase difference of the phase shift film 2 with respect to the light (wavelength 193 nm) of the exposure light of the ArF excimer laser were measured using the above-described phase shift amount measuring apparatus, the transmittance was 27.7%. The phase difference was 179.3 degrees (deg). Further, when the optical characteristics of the first B layer 21, the second B layer 22, and the third B layer 23 of the phase shift film 2 were measured by the above-mentioned spectral ellipsometer, the first B layer 21 had a refractive index n _1B of 1.990, The extinction coefficient k _1B is 0.085, the second B layer 22 has a refractive index n _2B of 2.595, the extinction coefficient k _2B is 0.357, and the third B layer 23 has a refractive index n _3B. 1.590, extinction coefficient _{k 3B} was 0.000. The back surface reflectance of the phase shift film 2 with respect to the light having the wavelength of the exposure light of the ArF excimer laser (the reflectance on the light-transmitting substrate 1 side) was 8.4%. When the phase shift film 2 and the light-shielding film 3 are laminated on the light-transmitting substrate 1, the back surface reflectance (reflectance on the light-transmitting substrate 1 side) with respect to the light having the wavelength of the exposure light of the ArF excimer laser is 8.3. %Met. When the optical density (OD) of the laminated structure of the phase shift film 2 and the light shielding film 3 with respect to light having a wavelength of 193 nm was measured, it was 3.0 or more.
Then, on the back surface of the light-transmitting substrate 1, the antireflection film 7 in which the first layer 71, the second layer 72, and the third layer 73 are laminated is formed with a thickness of 41 nm under the same film forming conditions as in the first embodiment. did.

According to the above procedure, a structure in which the phase shift film 2 including the first B layer 21, the second B layer 22, and the third B layer 23, the light-shielding film 3, and the hard mask film 4 are provided on the translucent substrate 1, The mask blank 120 of Example 3 including the antireflection film 7 having a three-layer structure on the back surface of the translucent substrate 1 was manufactured.
The back surface reflectance of the mask blank 120 was measured and found to be 0.6%.

[Manufacture of phase shift mask]
Next, using the mask blank 120 of the third embodiment, a phase shift mask 220 of the third embodiment was manufactured in the same procedure as in the first embodiment.

  Using the AIMS 193 (manufactured by Carl Zeiss), a simulation of an exposure transfer image when the phase shift mask 220 was exposed and transferred to a resist film on a semiconductor device with exposure light of an ArF excimer laser was performed. When the exposure transfer image obtained by this simulation was verified, the design specification was sufficiently satisfied. Further, in the exposure transfer image, no CD variation due to reflection of a barcode or an alignment mark was observed. As described above, even if the phase shift mask 220 manufactured from the mask blank of the third embodiment is set in the exposure apparatus and subjected to the exposure and transfer with the exposure light of the ArF excimer laser, the phase shift mask 220 can be applied to the resist film on the semiconductor device. It can be said that exposure transfer can be performed with high precision.

(Comparative Example 1)
[Manufacture of mask blanks]
The mask blank of Comparative Example 1 was manufactured in the same procedure as in Example 2 except for the antireflection film. The antireflection film of Comparative Example 1 has a configuration in which the first layer and the second layer of the antireflection film of Example 2 are interchanged.
Specifically, a light-transmitting substrate is placed in a single-wafer DC sputtering apparatus so that the back surface of the light-transmitting substrate is exposed, and argon (Ar) and nitrogen (N ₂ ), The second layer of an antireflection film made of silicon and nitrogen (SiN film Si: N = 43 atomic%) on the back surface of the light-transmitting substrate by reactive sputtering (RF sputtering) using a mixed gas of sputtering gas. (57 atomic%) with a thickness of 6 nm. Subsequently, silicon and nitrogen are formed on the first layer 71 by reactive sputtering (RF sputtering) using a mixed gas of argon (Ar) and nitrogen (N ₂ ) as a sputtering gas using a silicon (Si) target. A second layer of the antireflection film (SiN film Si: N = 68 atomic%: 32 atomic%) was formed with a thickness of 20 nm. Subsequently, reflection of silicon and oxygen is performed on the second layer by reactive sputtering (RF sputtering) using a silicon (Si) target and a mixed gas of argon (Ar) and oxygen (O ₂ ) as a sputtering gas. A third layer of the prevention film (SiO film: Si: O = 33 at%: 67 at%) was formed with a thickness of 15 nm. According to the above procedure, the antireflection film 7 in which the first layer, the second layer, and the third layer were stacked in contact with the back surface of the translucent substrate was formed with a thickness of 41 nm.
In other words, the antireflection film of Comparative Example 2 has a relation of n ₁ <n ₂ and n ₂ > n ₃ with respect to the refractive index at the wavelength of the exposure light of the first layer, the second layer, and the third layer, and extinction. Neither the relationship of k ₁ > k ₂ > k ₃ for the coefficient nor the relationship of d ₁ > d ₂ and d ₂ <d ₃ for the film thickness is satisfied.

  The reflectivity of the antireflection film on the back surface with respect to the exposure light of the ArF excimer laser was 18.8%, which was significantly high.

  Further, a thin film for pattern formation functioning as a phase shift film, a light-shielding film and a hard mask film are provided in this order on the surface of the light-transmitting substrate in the same manner as in the second embodiment. On the back surface, an antireflection film having the structure described above in Comparative Example 1 was formed to manufacture a mask blank. The mask blank of Comparative Example 1 had a rear surface reflectance of 18.8% with respect to the exposure light of the ArF excimer laser, which was significantly higher.

[Manufacture of phase shift mask]
Next, using the mask blank of Comparative Example 1, a phase shift mask of Comparative Example 1 was manufactured in the same procedure as in Example 1.

Simulation of an exposure transfer image when the halftone phase shift mask of Comparative Example 1 was exposed and transferred to a resist film on a semiconductor device by using exposure light of an ArF excimer laser using AIMS193 (manufactured by Carl Zeiss). Was done. When the exposure transfer image obtained by the simulation was verified, the design specification was not satisfied. From the above, it can be said that the phase shift mask manufactured from the mask blank of Comparative Example 2 cannot perform exposure transfer with high accuracy on the resist film on the semiconductor device.
Also, based on the measurement results of the back surface reflectance of the mask blank 120 of Example 3, when the antireflection film of Comparative Example 1 was applied to the antireflection film 7 of the mask blank 120 of Example 3, it was manufactured from this mask blank. It is presumed that the phase shift mask cannot perform exposure transfer with high accuracy on a resist film on a semiconductor device.

1 Translucent substrate 2 Pattern forming thin film (etching stopper / hard mask film, phase shift film)
21 1A layer, 1B layer 22 2A layer, 2B layer 23 3A layer, 3B layer 24 4A layer 2a Thin film pattern (phase shift pattern)
3 light-shielding film 3a, 3b light-shielding pattern 4 hard mask film 4a hard mask pattern 5a first resist pattern 6b, 6c second resist pattern 7 anti-reflection film 71 first layer 72 second layer 73 third layer 100, 110, 120 Mask blank 200, 210, 220 Phase shift mask

Claims (18)

A mask blank comprising a light-transmitting substrate having two opposing main surfaces and a pattern-forming thin film provided on one of the main surfaces,
An anti-reflection film having a structure in which a first layer, a second layer, and a third layer are stacked in this order from the light-transmitting substrate side on the other main surface;
When the refractive indices of the first layer, the second layer, and the third layer at the wavelength of the exposure light of the ArF excimer laser are n ₁ , n ₂ , and n ₃ , respectively, n ₁ <n ₂ and n ₂ > n. _Satisfy the relationship of ₃ ,
The first layer, when the second layer and the extinction coefficient at the wavelength of the exposure light of the third layer was _{k 1,} k 2, _{k 3 respectively,} satisfy the relationship of k _1> k 2> _{k 3} ,
The first layer, when the thickness of the second layer and the third layer and _{d 1,} d 2, _{d 3, respectively,} and satisfy the relationship d 1> _{d 2} and _d 2 _{<d 3} Mask blank. When the refractive index of the light-transmitting substrate at the wavelength of the exposure light is n _S , the relationship of n _S <n ₁ <n ₂ is satisfied;
_2. The mask blank according to claim _{1, wherein} a relationship of k _S <k ₂ <k ₁ is satisfied, where k _S is an extinction coefficient of the light-transmitting substrate at the wavelength of the exposure light.   The mask blank according to claim 1, wherein the first layer is provided in contact with a surface of the translucent substrate. The first layer is formed of a material including silicon and nitrogen, or a material including one or more elements selected from a semimetal element and a nonmetal element, and silicon and nitrogen,
The second layer is formed of a material including silicon and nitrogen, or a material including one or more elements selected from metalloid elements and nonmetal elements, and silicon and nitrogen,
The said 3rd layer is formed with the material which consists of silicon and oxygen, or the material which consists of one or more elements selected from a semimetal element and a nonmetal element, and silicon and oxygen. 4. The mask blank according to any one of items 1 to 3.   The mask blank according to claim 4, wherein the second layer has a higher nitrogen content than the first layer. The pattern forming thin film includes a phase shift film,
The phase shift film has a structure in which a first A layer, a second A layer, and a third A layer are stacked in this order from the translucent substrate side,
When the refractive indices of the first A layer, the second A layer, and the third A layer at the wavelength of the exposure light are n _1A , n _2A , and n _3A , respectively, the relationship of n _1A > n _2A and n _2A <n _3A is satisfied. The filling,
When the extinction coefficients of the first A layer, the second A layer, and the third A layer at the wavelength of the exposure light are k _1A , k _2A , and k _3A , respectively, k _1A <k _2A and k _2A > k _3A Fill the relationship,
When the thicknesses of the first A layer, the second A layer, and the third A layer are d _1A , d _2A , and d _3A , respectively, the relationship of d _1A <d _3A and d _2A <d _3A is satisfied. The mask blank according to any one of claims 1 to 5, wherein The mask blank according to claim 6, wherein the thickness _d3A of the third A layer is at least twice the thickness _d1A of the second A layer.   The mask blank according to claim 6, wherein the first A layer is provided in contact with a surface of the translucent substrate.   The first A layer, the second A layer, and the third A layer are formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and nitrogen. The mask blank according to any one of claims 6 to 8, wherein:   The mask blank according to claim 9, wherein the second A layer has a lower nitrogen content than the first A layer and the third A layer.   The phase shift film has a function of transmitting the exposure light at a transmittance of 2% or more, and has passed through the air by the same distance as the thickness of the phase shift film with respect to the exposure light transmitted through the phase shift film. The mask blank according to any one of claims 6 to 10, having a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the exposure light. The pattern forming thin film includes a phase shift film,
The phase shift film has a structure in which a first B layer and a second B layer are stacked in this order from the transparent substrate side,
When the refractive index of the first B layer and the second B layer at the wavelength of the exposure light is n _1B and n _2B , respectively, the relationship of n _1B <n _2B is satisfied;
When the extinction coefficients at the wavelength of the exposure light of the first B layer and the second B layer are k _1B and k _2B , respectively, the relationship of k _1B <k _2B is satisfied;
Wherein the 1B layer and the second 2B layer thickness each _d 1B _of, when the _{d 2B,} the mask blank according to any one of claims 1 to 5, characterized by satisfying the relation of d 1B _{<d 2B} .   The mask blank according to claim 12, wherein the first B layer is provided in contact with a surface of the translucent substrate. The first B layer is formed of a material including silicon, nitrogen, and oxygen, or a material including one or more elements selected from a semimetal element and a nonmetal element, and silicon, nitrogen, and oxygen;
13. The method according to claim 12, wherein the second B layer is formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from metalloid elements and nonmetal elements, and silicon and nitrogen. Or the mask blank according to 13.   The mask blank according to claim 14, wherein the second B layer has a higher nitrogen content than the first B layer.   The phase shift film has a function of transmitting the exposure light at a transmittance of 15% or more, and has passed the air by the same distance as the thickness of the phase shift film with respect to the exposure light transmitted through the phase shift film. The mask blank according to any one of claims 12 to 15, having a function of generating a phase difference of 150 degrees or more and 200 degrees or less with the exposure light.   17. A transfer mask, wherein a transfer pattern is provided on the translucent substrate or the pattern forming thin film in the mask blank according to any one of claims 1 to 16.   A method for manufacturing a semiconductor device, comprising a step of exposing and transferring a transfer pattern onto a resist film on a semiconductor substrate using the transfer mask according to claim 17.

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