JP2018010081A - Phase shift mask blank, method for manufacturing phase shift mask using the same, and phase shift mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a phase shift mask blank for improving a resolution limit of a line assist pattern and a space assist pattern by a normal phase shift mask process.SOLUTION: The phase shift mask blank includes a phase shift film and an etching mask laminated in this order on a substrate. The etching mask is composed of two-layer films both containing chromium, oxygen and nitrogen, in which the underlay film in the two-layer films contains chromium by 30 atomic% or more and less than 40 atomic%, oxygen by 55 atomic% or more and nitrogen by less than 10 atomic %; and the overlay film in the two-layer films contains chromium by 30 atomic% or more and less than 40 atomic%, oxygen by less than 10 atomic% and nitrogen by 55 atomic% or more.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a phase shift mask blank used in the manufacture of semiconductor devices and the like, a method of manufacturing a phase shift mask using the same, and a phase shift mask.

  In recent years, with the miniaturization of semiconductor elements, high resolution is required for projection exposure. Therefore, in the photomask field, a phase shift method has been developed as a technique for improving the resolution of a transfer pattern. The principle of the phase shift method is that the transmitted light interferes with each other by adjusting the phase of the transmitted light that has passed through the opening to be approximately 180 degrees reversed from the phase of the transmitted light that has passed through the portion adjacent to the opening. The light intensity at the boundary is weakened (phase shift effect), and as a result, the resolution and depth of focus of the transfer pattern are improved. Photomasks using this principle are generally called phase shift masks.

  The phase shift mask blank used for the phase shift mask has the most general structure in which a phase shift film and a light shielding film are sequentially laminated on a transparent substrate such as a glass substrate. The phase shift film usually has a phase difference of 175 to 180 degrees and a transmittance of about 6%, and is mainly formed of a single layer film or a multilayer film containing MoSi (molybden silicide) as a main component. The light shielding film is adjusted to have a desired transmittance and film thickness combined with the phase shift film, and is mainly formed of a film containing Cr (chromium) as a main component. The light shielding film usually has an etching mask function for etching the phase shift film.

  As a pattern formation method of the phase shift mask, a resist film is formed on the light shielding film of the phase shift mask blank, a pattern is drawn on the resist film by light or an electron beam, and this is developed to form a resist pattern. Using the resist pattern as an etching mask, the light shielding film is etched to form a light shielding film pattern. Further, a general method is to form the phase shift pattern by etching the phase shift film using the light shielding film pattern as an etching mask and then removing the resist film and the light shielding film.

  For phase shift masks that require highly accurate pattern formation, dry etching using gas plasma is the mainstream for etching. For dry etching of a light shielding film containing Cr as a main component, chlorine-based etching (Cl / O system) containing oxygen, and for dry etching of a phase shift film containing MoSi as a main component, fluorine-based etching (F system) Is used.

  With the miniaturization of the transfer pattern, a technique for finely forming the phase shift mask pattern is also required. In particular, the assist pattern for assisting the resolution of the main pattern of the phase shift mask needs to be formed smaller than the main pattern so that it is not transferred onto the wafer during exposure. In a phase shift mask having a minimum circuit line width of 14 nm on a wafer, the assist pattern line width is required to be 50 nm or less. At the same time, a line width of 70 nm or less is also required for an assist pattern in a space that becomes a reverse tone (black and white inversion).

  A chemically amplified resist for forming a fine pattern is composed of a base resin, an acid generator and the like, and can cause many reactions by the acid generated by exposure acting as a catalyst. As a result, high sensitivity can be achieved and a fine phase shift mask pattern of 0.2 μm or less can be formed. However, the chemically amplified resist reaches the resolution limit because the fine pattern collapses due to the collision of the developer in the development process.

Japanese Patent No. 5797812

Tatsuo Maya, “Fundamentals of Ultra-Fine Machining-Electronic Device Process Technology-Second Edition”, Nikkan Kogyo Shimbun, September 28, 2001, p. 66-70

  Therefore, in the method described in Patent Document 1, in order to produce a fine assist pattern, pattern collapse in the development process is reduced by forming a resist thin film. For this purpose, a Cr film having a high etching rate was developed by adding carbon to the Cr film as an etching mask. As a result, the initial resist was thinned to improve pattern collapse in the development process. However, since the Cr film is easily etched, a large side etching occurs in the horizontal direction, so that a part of the Cr film is thinned or disappeared during the etching of the Cr film, and the phase shift is performed using the remaining Cr film as a mask. When the film is etched, a desired dimension cannot be obtained, resulting in a defective pattern shape.

  Further, it is known that the Cr film containing carbon described in Patent Document 1 has a large film loss due to cleaning. Therefore, when the resist film is removed after the Cr film is etched and then the phase shift film is etched, the size of the Cr film is reduced in the resist film. Further, after removing the resist with a solvent, rinsing with pure water is performed to remove the solvent. However, if the Cr pattern is thin, the pattern disappears from the Cr film. Next, when the phase shift film is etched, a problem that a desired pattern cannot be produced is caused.

  In the case of a phase shift mask, it is generally required to form an outer peripheral pattern having a transmittance of 0.1% or less in the outer peripheral portion of the mask outside the effective area including the circuit pattern, including the phase shift film and the light shielding film. The outer peripheral pattern is for shielding external light and leakage light at the time of transfer exposure, and preventing multiple exposure when performing transfer exposure on a single wafer with multiple surfaces. When carbon is added to the Cr film, which is a light shielding film, the transmittance of the film increases. Therefore, in order to reduce the transmittance to 0.1% or less by combining the phase shift film and the light shielding film, it is necessary to increase the thickness of the Cr film. There is. In this case, it becomes difficult to achieve the resolution of the space assist pattern. This is because the etchant during the dry etching does not reach the bottom of the Cr film in the space and causes a defect.

  The present invention has been made to solve the above-described problems, and solves the line assist pattern and the space assist pattern by a normal phase shift mask process that does not require a special development process or dry etching process. It is an object to provide a phase shift mask blank that improves the image limit.

As means for solving the above problems, the invention of claim 1 is a phase shift mask blank comprising a laminated film in which a phase shift film and an etching mask are laminated in this order on a substrate,
Each of the etching masks consists of a two-layer film containing chromium, oxygen, and nitrogen,
The lower layer film of the two-layer film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content of less than 10 atomic%,
The upper layer film of the two-layer film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of less than 10 atomic%, and a nitrogen content of 55 atomic% or more. This is a phase shift mask blank.

  According to a second aspect of the present invention, the etching mask has a total film thickness of the two-layer film of 30 nm to 60 nm, and the phase shift film has a transmittance of 6% to 20% for exposure light. The phase shift mask blank according to claim 1, wherein the phase shift mask blank is 60 nm or more and 90 nm or less.

  According to a third aspect of the present invention, the etching mask has a total film thickness of the two-layer film of 30 nm or more and 60 nm or less, and a multilayer reflection film for extreme ultraviolet region light between the substrate and the phase shift film. The phase shift mask blank according to claim 1 is characterized.

  The invention according to claim 4 is the phase shift mask blank according to any one of claims 1 to 3, further comprising a resist film having a thickness of 70 nm to 125 nm on the upper layer film. is there.

  The invention according to claim 5 is characterized in that a sheet resistance value of the laminated film composed of the phase shift film and the etching mask is 400Ω / □ or less. This is a shift mask blank.

Invention of Claim 6 is a manufacturing method of the phase shift mask using the phase shift mask blank as described in any one of Claims 1-5,
Forming a pattern on the etching mask by performing dry etching using a chlorine-based gas containing oxygen on the etching mask using the resist pattern formed on the etching mask as a mask;
Forming a pattern on the phase shift film by performing dry etching using a fluorine-based gas on the phase shift film using the pattern formed on the etching mask as a mask;
A method of manufacturing a phase shift mask comprising the step of removing the etching mask by performing dry etching using a chlorine-based gas containing oxygen after pattern formation on the phase shift film. .

The invention of claim 7 is a phase shift mask comprising a circuit pattern made of a phase shift film on a substrate,
A pattern of a laminated film in which a phase shift film and an etching mask are laminated in this order on the outer periphery of the mask outside the effective area including the circuit pattern,
The uppermost layer film farthest from the substrate in the laminated film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of less than 10 atomic%, and a nitrogen content of 55 atomic% or more.
The film following the uppermost film in the laminated film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content of less than 10 atomic%. A phase shift mask characterized by the above.

According to the phase shift mask blank of the present invention, the etching mask is a two-layer film of a Cr-oxynitride film containing a lot of nitrogen and a Cr-oxynitride film containing a lot of oxygen, so that the dry etching cross-sectional shape of the etching mask is good It is possible to keep on. That is, with respect to the assist pattern of a line having a dimension of 50 nm or less, side etching in the horizontal direction does not occur during dry etching of the etching mask, and thinning and disappearance of the dry etching film can be reduced. Further, by using the two-layer film, the thickness of the etching mask can be made thinner than that of the carbon-containing Cr film. As a result, the etchant can be delivered to the bottom of the space part during dry etching of the etching mask, and the omission defect can be improved. As a result, a phase shift mask with improved resolution of the assist pattern can be obtained for the space.

The schematic cross section which shows the structure of the transmission type phase shift mask blank which is (a) 1st Embodiment of this invention, and (b) 2nd Embodiment. The schematic cross section which shows the structure of the reflection type phase shift mask blank which is the 3rd Embodiment of this invention. The schematic cross section which shows the structure of the transmission type phase shift mask which is the 4th Embodiment of this invention. The schematic cross section for demonstrating the etching condition of the etching mask in the manufacturing process of the phase shift mask (transmission type) of this invention. The schematic cross section which shows the manufacturing process of the phase shift mask (transmission type) of this invention. The schematic cross section for demonstrating the etching condition of the to-be-etched film in the chamber of a general dry etching apparatus.

  Hereinafter, a structure of a phase shift mask blank according to an embodiment of the present invention, and a manufacturing method and structure of the phase shift mask will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component unless there is a reason for convenience, and the overlapping description is abbreviate | omitted. Further, in the drawings used in the following description, in order to make the features easy to understand, the portions that become the features may be shown in an enlarged manner, and the dimensional ratios of the respective components are not necessarily the same as the actual ones.

  FIG. 1 is a schematic cross-sectional view showing the structure of a transmission type phase shift mask blank that is (a) the first embodiment and (b) the second embodiment of the present invention. The phase shift mask blank 200 according to the first embodiment of the present invention includes a phase shift film 102 that provides a post-mask phase shift effect on a transparent substrate 103, and an etching mask (in contact with the phase shift film 102). 2 layers of an upper layer film 100 and a lower layer film 101). The phase shift mask blank 250 of the second embodiment further includes a resist 104 on the phase shift mask blank 200 of the first embodiment.

  The upper layer film 100 of the etching mask is a film having a Cr content of 30 atomic% or more and less than 40 atomic%, an oxygen content of less than 10 atomic%, and a nitrogen content of 55 atomic% or more. The film has a Cr content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content of less than 10 atomic%. Therefore, the etching mask in the phase shift mask blank of the present invention is a two-layer film made of Cr based on both upper and lower layers. The reason why the composition ratio of the upper layer film 100 and the lower layer film 101 of the etching mask is defined as described above will be described later.

  In the phase shift mask blank 250 of the second embodiment, the film thickness of the resist 104 is preferably 70 nm or more and 125 nm or less in order to prevent the resist pattern from collapsing when forming a fine pattern.

  The etching mask preferably has a total film thickness of two layers of an upper layer film and a lower layer film of 30 nm or more and 60 nm or less. If the total film thickness is less than 30 nm, the risk of disappearing during the etching of the phase shift film increases, and it becomes difficult to suppress the transmittance of the outer peripheral pattern to 0.1% or less. On the other hand, if the thickness is larger than 60 nm, the omission defect is likely to occur with respect to the preferable resist film thickness (70 nm to 125 nm), and it becomes difficult to form an etching mask pattern having a good shape and size.

  In the phase shift mask blank of the present invention, as described above, the upper layer film 100 of the etching mask is a Cr film having a high nitrogen content, and the lower layer film 101 of the etching mask is a Cr film having a high oxygen content. The reason why the lower layer film 101 of the etching mask is a film having a high oxygen content is that, as will be described later, the oxidation component in a portion where side etching is likely to occur during etching is increased to suppress side etching. However, when the oxidation component increases, the transparency of the film increases and it becomes difficult to suppress the transmittance of the outer peripheral pattern to 0.1% or less. For this reason, the upper layer film 100 of the etching mask is made a Cr film having a high nitrogen content, thereby suppressing an increase in transmittance.

  The etching mask has a two-layer structure of a Cr film (upper layer film) with a high nitrogen content and a Cr film (lower layer film) with a high oxygen content, and the total film thickness of the two layers is 30 nm to 60 nm as described above. In order to reduce the transmittance of the outer peripheral pattern composed of the laminated film of the phase shift film and the etching mask to 0.1% or less, the upper layer film 100 has a Cr content of 30 atomic% or more and less than 40 atomic% and contains oxygen The film has a composition ratio of less than 10 atomic% and a nitrogen content of 55 atomic% or more, and the lower layer film 101 has a Cr content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content. A film having a composition ratio of less than 10 atomic% is preferable.

The upper layer film 100 and the lower layer film 101 do not necessarily have a constant composition ratio as long as they are within the above composition ratio. That is, a composition ratio gradient film in which the composition ratio continuously changes within the above composition ratio may be used. Such a composition ratio gradient film can be produced, for example, by controlling the Ar / O ₂ gas flow rate ratio or Ar / N ₂ gas flow rate ratio during sputtering film formation to change continuously.

  The phase shift film preferably has a transmittance with respect to exposure light of 6% or more and 20% or less because the resolution of the transfer pattern and the depth of focus can be improved by the phase shift effect according to the exposure conditions. Further, the thickness of the phase shift film is preferably 60 nm or more and 90 nm or less in order to obtain a phase difference of about 180 degrees and the transmittance. The phase shift film may be a single layer film or a multilayer film as long as the above conditions are satisfied.

  FIG. 2 is a schematic cross-sectional view showing the structure of a reflective phase shift mask blank 300 according to the third embodiment of the present invention. In the third embodiment, the total thickness of the two-layer films (310, 311) is 30 nm or more and 60 nm or less, and the multilayer reflective film 314 for extreme ultraviolet region light is provided between the substrate 313 and the phase shift film 312 in the etching mask. I have. Here, the wavelength of the extreme ultraviolet light is 13 nm to 14 nm.

  In the phase shift mask blanks of the first to third embodiments, the conductivity of the laminated film composed of the phase shift film and the etching mask is 400 Ω / □ when the laminated film is formed on a non-conductive substrate. The following is preferable. When the sheet resistance is larger than 400Ω / □, charge-up occurs during electron beam drawing, and the drawing pattern is liable to be displaced. It is preferable that the etching mask has a two-layer structure of not only a lower layer film having a high oxygen content but also an upper layer film having a high nitrogen content so that the sheet resistance value is 400 Ω / □ or less.

  FIG. 3 is a schematic cross-sectional view showing the structure of a transmission type phase shift mask according to the fourth embodiment of the present invention. It is manufactured using the phase shift mask blank of the first and second embodiments. In the fourth embodiment, a circuit pattern including the phase shift film pattern 102a is provided, and the phase shift film pattern 102a and the etching mask (upper layer film) pattern 100a are provided on the outer periphery of the mask outside the effective area including the circuit pattern. Similarly, an outer peripheral pattern 106 in which the lower layer film pattern 101a is laminated is provided. Here, the upper layer film farthest from the substrate 103 is a film having a chromium content of 30 atomic% to less than 40 atomic%, an oxygen content of less than 10 atomic%, and a nitrogen content of 55 atomic% or more. The film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content of less than 10 atomic%. The transmittance of the outer peripheral pattern 106 with respect to the exposure light is preferably 0.1% or less.

  By using the reflective phase shift mask blank according to the third embodiment shown in FIG. 2, a laminated film is formed on the outer periphery of the mask similarly outside the effective area including the circuit pattern and the circuit pattern formed of the phase shift film pattern. Although a reflection type phase shift mask having an outer peripheral pattern made of can be produced, illustration is omitted. The reflectance of the outer peripheral pattern with respect to the exposure light is desirably 0.1% or less.

  Hereinafter, in the phase shift mask blank of the present invention, the reason why a fine mask pattern can be obtained without side etching during etching of the etching mask will be described. For convenience, the situation of the conventional phase shift mask blank will be described first, and the phase shift mask blank of the present invention will be described in comparison.

  FIG. 6 is a schematic cross-sectional view for explaining a situation during etching of a film to be etched in a chamber of a general dry etching apparatus. There are several types of dry etching apparatuses using gas plasma. Here, the most commonly used RIE (Reactive ion etching) system is shown.

  In the plasma, the introduced gas collides with electrons, and reactive ions and active radicals dissociated into various forms are generated together with neutral particles, which causes etching. In the RIE method, a film to be etched was placed. The electric field generated by the ion sheath generated on the electrode side is used. That is, etching progresses when the cations accelerated by the electric field created by the ion sheath (lower potential becomes closer to the surface to be etched) bombard the radicals adsorbed on the surface to be etched.

  Here, as shown in FIG. 6A, the electric field is distorted by the resist pattern 504a (in the figure, the lines of electric force below the opening are omitted), and the resist pattern 504a is charged so that an acceleration trajectory is formed. Bending cations are born and bombard the sidewalls of the film to be etched together with cations scattered by collision with neutral particles (not shown). In the case where the film to be etched is Si or the like, a side wall protective film 501a generated from the introduced gas or etching product is formed on the side wall of the film to be etched, and side etching does not occur in order to prevent side wall etching (for example, Non-patent document 1).

In the case of Cr dry etching, since Cl ₂ gas alone does not proceed, a Cl / O-based gas is used, and etching proceeds by generating CrO ₂ Cl ₂ having a high vapor pressure. However, this reaction is radical-based etching, and a sidewall protective film cannot be formed. Therefore, as shown in FIG. 6B, the side wall is etched by radical reaction and ion bombardment, and the cross-sectional shape of the Cr pattern tends to be a bow shape with a narrow center or a reverse taper shape with a narrow bottom, like etching of Si A vertical shape cannot be obtained.

  FIG. 4 is a schematic cross-sectional view for explaining a situation during etching of the etching mask in the manufacturing process of the phase shift mask of the present invention. In the phase shift mask blank of the present invention, the etching mask is a Cr-based two-layer film, and the lower layer film is an oxygen-rich Cr-oxynitride film. On the side, it is easier to charge than conventional Cr-based films. For this reason, the energy of the cation impacting the side wall is relaxed, and the number of ions traveling in the direction perpendicular to the surface to be etched increases. In addition, the increase in the oxidation component of Cr causes passivation and suppresses etching by radicals. In this way, in the phase shift mask blank of the present invention, the occurrence of side etching is suppressed.

  FIG. 5 is a flowchart showing a phase shift mask manufacturing process using the phase shift mask blank of the present invention from the form of the phase shift mask blank 250 of the second embodiment in which the resist 104 is formed. Specific contents will be described in Examples.

In the embodiment, in order to verify the effectiveness of the phase shift mask blank of the present invention and the method of manufacturing the phase shift mask using the same, the resolution limit of the fine pattern corresponding to the line and space assist pattern is examined. did.

  A phase shift mask blank 200 according to the first embodiment of the present invention was prepared. Here, the phase shift film and the Cr-based two-layer film were as follows.

<Phase shift film>
MoSi single layer film, film thickness 65nm

<Cr-based upper layer film>
Cr content: 35 atm%, oxygen content: 5 atm%, nitrogen content: 60 atm%,
Film thickness: 15nm

<Cr-based underlayer>
Cr content: 35 atm%, oxygen content: 60 atm%, nitrogen content: 5 atm%,
Film thickness: 15nm
On the phase shift mask blank 200, a negative type chemically amplified electron beam resist SEBN3015 (manufactured by Shin-Etsu Chemical Co., Ltd.) is spin-coated to a thickness of 1500 mm to form a resist film, and the phase shift mask blank 250 of the second embodiment is used. (FIG. 5 <S-1>).

Next, the short side dimension of the isolated line pattern and the isolated space pattern is changed by 2 nm from the pattern size of 30 nm to 80 nm so as to correspond to the assist pattern of the line and space at a dose of 35 μC / cm ² , respectively. Was set to 120 nm, and 50,000 electron beams were drawn with respective line widths (short side dimensions). Thereafter, heat treatment (PEB = Post exposure bake) was performed at 110 ° C. for 10 minutes using a heat treatment apparatus. Next, development was performed for 90 seconds by paddle development to form a resist pattern 104a (FIG. 5 <S-2>).

  Next, dry etching was performed on the etching mask composed of a Cr-based two-layer film using a chlorine-based gas containing oxygen under the following conditions (FIG. 5 <S-3>). At this time, no omission of etching occurred.

<Dry etching conditions for Cr-based two-layer film>
Apparatus: ICP (Inductively Coupled Plasma = inductively coupled plasma) System gas: Cl ₂ + O ₂ + He, gas pressure: 6 mTorr
ICP power: 400W

Next, dry etching was performed on the phase shift film using a fluorine-based gas under the following conditions (FIG. 5 <S-4>).

<MoSi phase shift film dry etching conditions>
Device: ICP
Gas: SF ₆ + O ₂ , Gas pressure: 5 mTorr
ICP power: 325W

  Next, the resist pattern 104a is stripped by washing with sulfuric acid (FIG. 5 <S-5>), and the etching mask patterns 100a and 101a are stripped by performing dry etching with a chlorine-based gas containing oxygen, thereby forming the present invention. The phase shift mask 400 using the phase shift mask blank was prepared (FIG. 5 <S-6>).

<Evaluation>
The resolution limit of the fine pattern was evaluated using an appearance inspection apparatus. When the inspection machine detects one or more pattern disappearances or pattern defects in isolated line patterns and isolated space patterns (50,000 each) with the short side dimension changed by 2 nm from 30 nm to 80 nm in design. Was defined as the defect, and the minimum dimension at which the inspection machine did not detect the defect was defined as the resolution limit. Table 1 shows the results. As a comparative example, the result of producing a phase shift mask using a conventional phase shift mask blank using a Cr-based single layer film as an etching mask is shown.

  As shown in Table 1, when the phase shift mask blank of the present invention was used, the resolution limit reached a finer line width as compared with the conventional blank, and it was confirmed that the resolution was improved. This is because the phase shift mask blank of the present invention uses an etching mask that does not cause side etching in the horizontal direction in the dry etching section of the etching mask. Thus, a phase shift mask blank that improves the resolution limit of the line assist pattern and the space assist pattern was obtained by a normal phase shift mask process that does not require a special development process or dry etching process.

  A phase shift mask blank of the present invention and a method of manufacturing a phase shift mask using the same include a phase shift mask blank for manufacturing a phase shift mask having a fine mask pattern such as a fine assist pattern, and manufacture of the phase shift mask. It is applicable as a method.

100, 310 .... Etching mask (upper layer film)
100a ... Etching mask (upper layer film) pattern 101, 311, ... Etching mask (lower layer film)
101a ... Etching mask (lower layer film) pattern 101b ... Etching mask (lower layer film) during etching
102, 312, 502 ... Phase shift film 102a ... Phase shift film pattern 103, 503 ... Transparent substrate 104, 504 ... Resist 104a, 504a ... Resist pattern 105 ...・ Effective area 106 ・ ・ ・ ・ Peripheral pattern 200, 250 ・ ・ ・ ・ Phase shift mask blank (transmission type)
300 ・ ・ ・ ・ Phase shift mask blank (reflection type)
313 ... substrate 314 ... multilayer reflective film 400, 450 ... phase shift mask (transmission type)
501, 601... Etched film during etching 501 a.

Claims (7)

A phase shift mask blank comprising a laminated film in which a phase shift film and an etching mask are laminated in this order on a substrate,
Each of the etching masks consists of a two-layer film containing chromium, oxygen, and nitrogen,
The lower layer film of the two-layer film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content of less than 10 atomic%,
The upper layer film of the two-layer film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of less than 10 atomic%, and a nitrogen content of 55 atomic% or more. Phase shift mask blank.   The etching mask has a total thickness of the two-layer film of 30 nm to 60 nm, and the phase shift film has a transmittance of 6% to 20% for exposure light and a thickness of 60 nm to 90 nm. The phase shift mask blank according to claim 1.   2. The etching mask according to claim 1, wherein the total thickness of the two-layer film is 30 nm or more and 60 nm or less, and a multilayer reflection film for extreme ultraviolet region light is provided between the substrate and the phase shift film. The described phase shift mask blank.   The phase shift mask blank according to claim 1, further comprising a resist film having a thickness of 70 nm to 125 nm on the upper layer film.   The phase shift mask blank according to any one of claims 1 to 4, wherein a sheet resistance value of the laminated film including the phase shift film and the etching mask is 400 Ω / □ or less. It is a manufacturing method of a phase shift mask using the phase shift mask blank according to any one of claims 1 to 5,
Forming a pattern on the etching mask by performing dry etching using a chlorine-based gas containing oxygen on the etching mask using the resist pattern formed on the etching mask as a mask;
Forming a pattern on the phase shift film by performing dry etching using a fluorine-based gas on the phase shift film using the pattern formed on the etching mask as a mask;
A method of manufacturing a phase shift mask, comprising the step of removing the etching mask by performing dry etching using a chlorine-based gas containing oxygen after pattern formation on the phase shift film. A phase shift mask having a circuit pattern made of a phase shift film on a substrate,
A pattern of a laminated film in which a phase shift film and an etching mask are laminated in this order on the outer periphery of the mask outside the effective area including the circuit pattern,
The uppermost layer film farthest from the substrate in the laminated film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of less than 10 atomic%, and a nitrogen content of 55 atomic% or more.
The film following the uppermost film in the laminated film is a film having a chromium content of 30 atomic% or more and less than 40 atomic%, an oxygen content of 55 atomic% or more, and a nitrogen content of less than 10 atomic%. A phase shift mask characterized by

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