JP6738941B2 - Mask blank, phase shift mask, and semiconductor device manufacturing method - Google Patents

Description

The present invention relates to a mask blank and a phase shift mask manufactured using the mask blank. The present invention also relates to a method of manufacturing a semiconductor device using the above phase shift mask.

In a semiconductor device manufacturing process, a fine pattern is formed by using a photolithography method. Further, a number of transfer masks are usually used for forming this fine pattern. In order to miniaturize the pattern of the semiconductor device, in addition to miniaturizing the mask pattern formed on the transfer mask, it is necessary to shorten the wavelength of the exposure light source used in photolithography. In recent years, an ArF excimer laser (wavelength 193 nm) is increasingly used as an exposure light source when manufacturing a semiconductor device.

One type of transfer mask is a halftone type phase shift mask. The halftone type phase shift mask has a light transmitting portion that transmits the exposure light and a phase shifting portion (of a halftone phase shift film) that diminishes and transmits the exposure light. The phase of the exposure light transmitted by is substantially inverted (phase difference of about 180 degrees). Due to this phase difference, the contrast of the optical image at the boundary between the light transmitting portion and the phase shift portion is increased, so that the halftone phase shift mask becomes a transfer mask with high resolution.

In the halftone phase shift mask, the higher the transmittance of the halftone phase shift film with respect to the exposure light, the higher the contrast of the transferred image tends to be. For this reason, a so-called high transmittance halftone type phase shift mask is used, especially when a high resolution is required. A molybdenum silicide (MoSi)-based material is widely used for the phase shift film of the halftone phase shift mask. However, it has recently been revealed that the MoSi-based film has low resistance to exposure light of an ArF excimer laser (so-called ArF light resistance).

A SiN-based material composed of silicon and nitrogen is also known as a phase shift film of a halftone type phase shift mask, and is disclosed in Patent Document 1, for example. Further, as a method of obtaining desired optical characteristics, Patent Document 2 discloses a halftone type phase shift mask using a phase shift film composed of a periodic multilayer film of a Si oxide layer and a Si nitride layer. It is described therein that, with respect to light having a wavelength of 157 nm, which is F ₂ excimer laser light, a predetermined phase difference can be obtained with a transmittance of 5%. Since a SiN-based material has high ArF light resistance, a high transmittance halftone phase shift mask using a SiN-based film as a phase shift film has been attracting attention.

JP-A-7-134392 Japanese Patent Publication No. 2002-535702

When a single-layer phase shift film made of a silicon nitride material is used, there is a limitation on the transmittance of ArF excimer laser exposure light (hereinafter referred to as ArF exposure light), and increasing the transmittance above 18% is a material. It is difficult due to its optical characteristics.

When oxygen is introduced into silicon nitride, the transmittance can be increased. However, when a single-layer phase shift film made of a silicon oxynitride material is used, etching selectivity with a translucent substrate formed of a material containing silicon oxide as a main component can be improved when patterning the phase shift film by dry etching. There is a problem of becoming smaller.

As a method for solving the above-mentioned problems, for example, a method in which the phase shift film has a two-layer structure composed of a silicon nitride layer and a silicon oxide layer which are sequentially arranged from the transparent substrate side can be considered. Patent Document 1 discloses a halftone type phase shift mask provided with a phase shift film having a two-layer structure composed of a silicon nitride layer and a silicon oxide layer, which are sequentially arranged from the transparent substrate side.

By using a two-layer structure composed of a silicon nitride layer and a silicon oxide layer as the phase shift film, the degree of freedom in designing the refractive index, the extinction coefficient, and the film thickness for ArF exposure light is increased, and the phase shift film having the two-layer structure is obtained. Can have a desired transmittance and phase difference for ArF exposure light. However, as a result of detailed study, it was found that the halftone phase shift mask provided with the phase shift film having a two-layer structure composed of a silicon nitride layer and a silicon oxide layer has the following problems.

Both the silicon nitride layer and the silicon oxide layer have significantly higher ArF light resistance than the MoSi-based film described above. However, the silicon nitride layer has lower ArF light resistance than the silicon oxide layer. That is, when a phase shift mask is manufactured from a mask blank provided with this phase shift film and the phase shift mask is set in an exposure apparatus and exposure transfer by ArF exposure light is repeated, the line width of the pattern of the phase shift film is reduced. The portion of the silicon nitride layer tends to be thicker than the portion of the silicon oxide layer. Therefore, although the silicon oxide layer is unlikely to be thickened by repeated irradiation of ArF exposure light, the line width of the pattern in the entire phase shift film is relatively large when it is repeatedly irradiated with ArF exposure light. There was a problem of becoming.

Further, both the silicon nitride layer and the silicon oxide layer have significantly higher resistance (chemical resistance) to a chemical solution used for cleaning and the like, as compared with the above-mentioned MoSi-based film. However, the silicon nitride layer has lower chemical resistance than the silicon oxide layer. That is, in the process of manufacturing a phase shift mask from a mask blank provided with this phase shift film, and when the cleaning with a chemical solution is repeatedly performed after manufacturing the phase shift mask, the line width of the pattern of the phase shift film is in the portion of the silicon oxide layer. Compared with this, the silicon nitride layer portion is more likely to decrease. Therefore, although the silicon oxide layer has high chemical resistance, there is a problem that the amount of reduction in the line width of the pattern in the entire phase shift film becomes relatively large when the cleaning with the chemical solution is repeated.

On the other hand, in the above-described two-layer structure phase shift film, when the material forming the high transmission layer is changed from silicon oxide to silicon oxynitride, the same optical characteristics as when the high transmission layer is formed of silicon oxide Can be obtained. However, even in the case of the phase shift film having this structure, problems of ArF light resistance and chemical resistance occur.

The present invention has been made to solve the above problems, and a phase shift film including at least a nitrogen-containing layer such as a silicon nitride layer and an oxygen-containing layer such as a silicon oxide layer on a transparent substrate. It is an object of the present invention to provide a mask blank for a halftone type phase shift mask in which the ArF light resistance and chemical resistance of the entire phase shift film are improved.

Another object of the present invention is to provide a phase shift mask manufactured using this mask blank. Further, the present invention aims to provide a method of manufacturing such a phase shift mask. The present invention has an object to provide a method for manufacturing a semiconductor device using such a phase shift mask.

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

(Structure 1)
A mask blank having a phase shift film on a transparent substrate,
The phase shift film includes at least a nitrogen-containing layer and an oxygen-containing layer,
The oxygen-containing 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 non-metal elements, and oxygen and silicon,
The nitrogen-containing layer is formed of a material consisting of silicon and nitrogen, or a material consisting of one or more elements selected from non-metal elements and metalloid elements, and nitrogen and silicon,
X-ray photoelectron spectroscopic analysis is performed on the nitrogen-containing layer to obtain a maximum peak PSi_f of photoelectron intensity of Si2p narrow spectrum in the nitrogen-containing layer, and X-ray photoelectron spectroscopic analysis is performed on the transparent substrate. A numerical value (PSi_f)/(PSi_s) obtained by dividing the maximum peak PSi_f in the nitrogen-containing layer by the maximum peak PSi_s in the nitrogen-containing layer when the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is acquired. Is 1.09 or less.

(Configuration 2)
2. The mask blank according to Structure 1, wherein the nitrogen-containing layer has a nitrogen content of 50 atomic% or more.
(Structure 3)
3. The mask blank according to Configuration 1 or 2, wherein the oxygen-containing layer has a total content of nitrogen and oxygen of 50 atomic% or more.

(Structure 4)
The mask blank according to any one of configurations 1 to 3, wherein the oxygen-containing layer has an oxygen content of 15 atomic% or more.
(Structure 5)
The maximum peak of the photoelectron intensity of the Si2p narrow spectrum is the maximum peak in the range of the binding energy of 96 [eV] or more and 106 [eV] or less, The mask blank according to any one of configurations 1 to 4. ..

(Structure 6)
6. The mask blank according to any one of Configurations 1 to 5, wherein the X-rays with which the phase shift film is irradiated by the X-ray photoelectron spectroscopy analysis are AlKα rays.
(Structure 7)
The number of Si ₃ N ₄ bonds present in the nitrogen-containing layer was determined to be Si ₃ N ₄ bonds, Si _a N _b bonds (where b/[a+b]<4/7), Si—Si bonds, Si—O bonds and 7. The mask blank according to any one of configurations 1 to 6, wherein a ratio divided by the total number of existing Si-ON bonds is 0.88 or more.

(Structure 8)
The phase shift film has a function of transmitting the exposure light of the ArF excimer laser with a transmittance of 10% or more, and has the same distance in the air as the thickness of the phase shift film with respect to the exposure light transmitted through the phase shift film. 8. The mask blank according to any one of configurations 1 to 7, having a function of causing a phase difference of 150 degrees or more and 200 degrees or less with the exposure light that has passed through.
(Configuration 9)
The mask blank according to any one of Configurations 1 to 8, further comprising a light-shielding film on the phase shift film.

(Configuration 10)
A phase shift mask comprising a phase shift film having a transfer pattern formed on a transparent substrate,
The phase shift film includes at least a nitrogen-containing layer and an oxygen-containing layer,
The oxygen-containing 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 non-metal elements, and oxygen and silicon,
The nitrogen-containing layer is formed of a material consisting of silicon and nitrogen, or a material consisting of one or more elements selected from non-metal elements and metalloid elements, and nitrogen and silicon,
X-ray photoelectron spectroscopic analysis is performed on the nitrogen-containing layer to obtain a maximum peak PSi_f of photoelectron intensity of Si2p narrow spectrum in the nitrogen-containing layer, and X-ray photoelectron spectroscopic analysis is performed on the transparent substrate. A numerical value (PSi_f)/(PSi_s) obtained by dividing the maximum peak PSi_f in the nitrogen-containing layer by the maximum peak PSi_s in the nitrogen-containing layer when the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is acquired. Is 1.09 or less.

(Configuration 11)
11. The phase shift mask according to Structure 10, wherein the nitrogen-containing layer has a nitrogen content of 50 atomic% or more.
(Configuration 12)
12. The phase shift mask according to Configuration 10 or 11, wherein the oxygen-containing layer has a total content of nitrogen and oxygen of 50 atomic% or more.

(Configuration 13)
13. The phase shift mask according to any one of Configurations 10 to 12, wherein the oxygen-containing layer has an oxygen content of 15 atomic% or more.
(Configuration 14)
The maximum peak of the photoelectron intensity of the Si2p narrow spectrum is the maximum peak in the range of binding energy of 96 [eV] or more and 106 [eV] or less, The phase shift according to any one of Configurations 10 to 13. mask.

(Structure 15)
15. The phase shift mask according to any one of Configurations 10 to 14, wherein the X-rays that are applied to the phase shift film in the X-ray photoelectron spectroscopy analysis are AlKα rays.
(Configuration 16)
The number of Si ₃ N ₄ bonds present in the nitrogen-containing layer was determined to be Si ₃ N ₄ bonds, Si _a N _b bonds (where b/[a+b]<4/7), Si—Si bonds, Si—O bonds and 16. The phase shift mask according to any one of Configurations 10 to 15, wherein a ratio divided by the total number of existing Si-ON bonds is 0.88 or more.

(Configuration 17)
The phase shift film has a function of transmitting the exposure light of the ArF excimer laser with a transmittance of 10% or more, and has the same distance in the air as the thickness of the phase shift film with respect to the exposure light transmitted through the phase shift film. 17. The phase shift mask according to any one of Structures 10 to 16, having a function of producing a phase difference of 150 degrees or more and 200 degrees or less with the exposure light that has passed through.
(Structure 18)
18. The phase shift mask according to any one of configurations 10 to 17, further comprising a light blocking film having a light blocking pattern formed on the phase shift film.

(Structure 19)
19. A method of manufacturing a semiconductor device, comprising the step of exposing and transferring a transfer pattern onto a resist film on a semiconductor substrate using the phase shift mask according to any one of Structures 10 to 18.

The mask blank of the present invention is a mask blank provided with a phase shift film on a transparent substrate, the phase shift film includes at least a nitrogen-containing layer and an oxygen-containing layer, the oxygen-containing layer is a silicon and oxygen. Or a material containing one or more elements selected from metalloid elements and non-metal elements, and oxygen and silicon, and the nitrogen-containing layer is a material containing silicon and nitrogen, or non-metal elements and semi-metal elements. The maximum peak PSi_f of the photoelectron intensity of the Si2p narrow spectrum in the nitrogen-containing layer is determined by performing X-ray photoelectron spectroscopy analysis on the nitrogen-containing layer, which is formed of a material composed of one or more elements selected from metallic elements and nitrogen and silicon. When the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is acquired by performing the X-ray photoelectron spectroscopy analysis on the transparent substrate, the maximum peak PSi_f in the nitrogen-containing layer is measured by the light transmission. The numerical value (PSi_f)/(PSi_s) divided by the maximum peak PSi_s in the flexible substrate is 1.09 or less. By using the mask blank having such a structure, ArF light resistance and chemical resistance of the entire phase shift film can be improved.

In addition, the phase shift mask of the present invention is characterized in that the phase shift film having a transfer pattern has the same structure as the phase shift film of the mask blank of the present invention. By using such a phase shift mask, ArF light resistance and chemical resistance of the entire phase shift film can be improved. Therefore, the phase shift mask of the present invention has high transfer accuracy when exposure transfer is performed to a transfer target such as a resist film on a semiconductor substrate.

The semiconductor device manufacturing method of the present invention is characterized by including a step of exposing and transferring a transfer pattern to a resist film on a semiconductor substrate using the phase shift mask of the present invention. Therefore, the semiconductor device manufacturing method of the present invention can perform the exposure transfer of the transfer pattern onto the resist film with high transfer accuracy.

It is sectional drawing which shows the structure of the mask blank in embodiment of this invention. FIG. 9 is a cross-sectional view showing a manufacturing process of the phase shift mask in the embodiment of the present invention. FIG. 3 is a diagram showing a result (Si2p narrow spectrum) of an X-ray photoelectron spectroscopy analysis performed on the phase shift film and the transparent substrate of the mask blank according to Example 1. FIG. 6 is a diagram showing a result (Si2p narrow spectrum) of an X-ray photoelectron spectroscopy analysis performed on the phase shift film and the transparent substrate of the mask blank according to Comparative Example 1.

First, the background to the completion of the present invention will be described. In the case where the phase shift film of the mask blank has a laminated structure including a silicon nitride-based material layer (nitrogen-containing layer) and a silicon oxide-based material layer (oxygen-containing layer), the inventors of the present invention performed ArF light resistance of the phase shift film. The research was conducted from the viewpoint of sex and chemical resistance.

The phenomenon that the line width of the pattern of the silicon-based material film becomes thick when irradiated with ArF exposure light occurs because the silicon atom in the state of being bound to another element (including another silicon atom) is excited. It is considered that the cause is that volume expansion occurs by breaking the bond and advancing the reaction of bonding with oxygen. Therefore, in the case of a silicon oxide-based material layer in which a large amount of silicon that has been bonded to oxygen is already present before the irradiation with ArF exposure light, the pattern line width due to volume expansion does not occur even when the ArF exposure light is irradiated. Hard to get fat. Further, silicon bonded to oxygen is less likely to dissolve in a chemical solution than silicon bonded to elements other than oxygen. By including oxygen in the silicon nitride-based material layer, ArF light resistance and chemical resistance can be enhanced. However, if oxygen is contained in the silicon nitride-based material layer, it is unavoidable that the refractive index n and the extinction coefficient k are lowered, and the degree of freedom in designing the phase shift film is greatly reduced. Therefore, this means is not applicable. It's hard.

As a result of earnest studies, the present inventors have found that if a silicon nitride-based material that is less likely to be excited by silicon when irradiated with ArF exposure light is used for the silicon nitride-based material layer of the phase shift film, The inventors have come to the idea that the ArF light resistance of the entire phase shift film can be improved.

The present inventors have used X-ray photoelectron spectroscopy (XPS:XPS) as an index of whether or not silicon in a silicon nitride-based material layer is in a state of being easily excited when exposed to ArF exposure light. -Ray Photoelectron Spectroscopy) was applied. First, it was examined that X-ray photoelectron spectroscopy analysis was performed on the silicon nitride-based material layer to obtain a Si2p narrow spectrum, and that the difference between the maximum peaks was used as an index. The maximum peak of the photoelectron intensity of the Si2p narrow spectrum in the silicon nitride-based material layer corresponds to the number of photoelectrons emitted from the bond of nitrogen and silicon per unit time. Photoelectrons are electrons that have been excited by the irradiation of X-rays and have jumped out of the atomic orbit. A material having a large number of photoelectrons emitted when it is irradiated with X-rays and easily excited is a material having a small work function. It can be said that such a silicon nitride-based material having a small work function is easily excited even when irradiated with ArF exposure light.

However, the number of photoelectrons detected by X-ray photoelectron spectroscopy varies depending on the measurement conditions (type of X-ray used, irradiation intensity, etc.) even with the same silicon nitride-based material layer, so it is used as it is as an index. It is not possible. As a result of research on this problem, the maximum peak of the photoelectron intensity of the Si2p narrow spectrum in the silicon nitride-based material layer divided by the maximum peak of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate may be used as an index. I came up with the idea.

The transparent substrate is formed of a relatively stable material containing SiO ₂ as a main component. The translucent substrate used for the mask blank is required to have very small variation in materials such as small variation in optical characteristics. Therefore, the variation of the work function of each material among the plurality of transparent substrates is very small. Under the same measurement conditions, the difference in the maximum peak of the photoelectron intensity of the Si2p narrow spectrum between different translucent substrates is small, so the influence of the difference in the measurement conditions is largely reflected in this maximum peak of the photoelectron intensity. The maximum peak of the photoelectron intensity of the Si2p narrow spectrum in the translucent substrate is the number of photoelectrons emitted from the bond of oxygen and silicon per unit time. It is a preferable reference value for correcting the difference in the maximum peak of the photoelectron intensity of.

As a result of further intensive research, the present inventors have provided on a translucent substrate a phase shift film including at least a silicon nitride-based material layer (nitrogen-containing layer) and a silicon oxide-based material layer (oxygen-containing layer). In the mask blank, when the X-ray photoelectron spectroscopy analysis was performed on the silicon nitride-based material layer and the light-transmissive substrate, the maximum peak PSi_f of the photoelectron intensity of the Si2p narrow spectrum in the silicon nitride-based material layer was determined to be translucent. It was concluded that the ArF light resistance can be enhanced if the numerical value (PSi_f)/(PSi_s) divided by the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the substrate is 1.09 or less.

On the other hand, in the silicon nitride-based material layer having the above numerical value (PSi_f)/(PSi_s) of 1.09 or less, it is difficult for silicon in the layer to be excited when it is irradiated with ArF exposure light. It can be said that such a silicon nitride-based material layer has a high abundance ratio of bonds between nitrogen and silicon in a strongly bonded state. It was concluded that when the chemical solution comes into contact with this silicon nitride-based material layer, the bond between nitrogen and silicon is hard to be broken, and it is difficult to dissolve in the chemical solution.

As a result of the above-mentioned intensive studies, the mask blank of the present invention was derived. That is, the mask blank of the present invention includes a phase shift film on a transparent substrate, and the phase shift film includes a nitrogen-containing layer (silicon nitride-based material layer) and an oxygen-containing layer (silicon oxide-based material layer). At least, the oxygen-containing 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 non-metal elements, and oxygen and silicon, and the nitrogen-containing layer is composed of silicon. Formed of a material consisting of nitrogen and silicon, or a material consisting of one or more elements selected from non-metal elements and semi-metal elements, nitrogen and silicon, and nitrogen-containing layers being subjected to X-ray photoelectron spectroscopy analysis. When the maximum peak PSi_f of the photoelectron intensity of the Si2p narrow spectrum in the layer is obtained, and the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is obtained by performing X-ray photoelectron spectroscopy analysis on the transparent substrate. The numerical value (PSi_f)/(PSi_s) obtained by dividing the maximum peak PSi_f in the nitrogen-containing layer by the maximum peak PSi_s in the translucent substrate is 1.09 or less.

Next, each embodiment of the present invention will be described. The mask blank of the present invention can be applied to a mask blank for producing a phase shift mask. Hereinafter, a mask blank for manufacturing a halftone type phase shift mask will be described. FIG. 1 is a sectional view showing a configuration of a mask blank 100 according to an embodiment of the present invention. The mask blank 100 shown in FIG. 1 has a structure in which a phase shift film 2, a light shielding film 3, and a hard mask film 4 are laminated in this order on a transparent substrate 1.

The translucent substrate 1 can be formed of a glass material such as quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO ₂ —TiO ₂ glass) in addition to synthetic quartz glass. Among these, synthetic quartz glass has a high transmittance for ArF excimer laser light (wavelength 193 nm) and is particularly preferable as a material for forming a transparent substrate of a mask blank.

The phase shift film 2 is required to have a transmittance that allows the phase shift effect to effectively function. The phase shift film 2 is required to have at least a transmittance of 1% or more for ArF exposure light. The phase shift film 2 preferably has a transmittance for ArF exposure light of 10% or more, more preferably 15% or more, and further preferably 20% or more.
Further, the phase shift film 2 is preferably adjusted so that the transmittance for ArF exposure light is 40% or less, and more preferably 30% or less.

In recent years, NTD (Negative Tone Development) has come to be used as an exposure/development process for a resist film on a semiconductor substrate (wafer), in which a bright field mask (transfer mask having a high pattern aperture ratio) is often used. Used. In the bright field phase shift mask, by setting the transmittance of the phase shift film to the exposure light to be 10% or more, the balance between the 0th order light and the 1st order light of the light transmitted through the light transmitting portion becomes good. When this balance is improved, the effect of the exposure light transmitted through the phase shift film interfering with the 0th-order light and attenuating the light intensity is further increased, and the pattern resolution on the resist film is improved. Therefore, the transmittance of the phase shift film 2 for ArF exposure light is preferably 10% or more. When the transmittance for ArF exposure light is 15% or more, the pattern edge enhancement effect of the transfer image (projection optical image) due to the phase shift effect is further enhanced. On the other hand, if the transmittance of the phase shift film 2 for ArF exposure light exceeds 40%, the influence of side lobes becomes too strong, which is not preferable.

In order to obtain an appropriate phase shift effect, the phase shift film 2 provides a predetermined phase difference between the transmitted ArF exposure light and the light that has passed through the air by the same distance as the thickness of the phase shift film 2. It is required to have a function to generate. Further, the phase difference is preferably adjusted so as to fall within a range of 150 degrees or more and 200 degrees or less. The lower limit value of the phase difference in the phase shift film 2 is more preferably 160 degrees or more, and further preferably 170 degrees or more. On the other hand, the upper limit value of the phase difference in the phase shift film 2 is more preferably 190 degrees or less.

The phase shift film 2 preferably has a thickness of 90 nm or less, and more preferably 80 nm or less. On the other hand, the phase shift film 2 preferably has a thickness of 40 nm or more. If the thickness of the phase shift film 2 is less than 40 nm, there is a possibility that the predetermined transmittance and phase difference required for the phase shift film may not be obtained.

The phase shift film 2 is a laminated film of two or more layers including at least a nitrogen-containing layer (silicon nitride material layer) and an oxygen-containing layer (silicon oxide material layer). The phase shift film 2 may have at least one nitrogen-containing layer and at least one oxygen-containing layer, and may further have one or more nitrogen-containing layers and oxygen-containing layers. For example, the phase shift film 2 may have a structure having two or more sets of a laminated structure including a nitrogen-containing layer and an oxygen-containing layer (a laminated structure of four or more layers), and oxygen between the two nitrogen-containing layers. The structure may be such that a containing layer is provided. The phase shift film 2 may include material layers other than the nitrogen-containing layer and the oxygen-containing layer as long as the effects of the present invention can be obtained.

The nitrogen-containing layer is preferably formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from non-metal elements and metalloid elements, and nitrogen and silicon. The nitrogen-containing layer may contain any metalloid element in addition to silicon. Among these semi-metal elements, it is preferable to contain 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.

The nitrogen-containing layer may contain any non-metal element in addition to nitrogen. In this case, the non-metal element includes a non-metal element in a narrow sense (nitrogen, carbon, oxygen, phosphorus, sulfur, selenium), halogen and noble gas. Among these non-metal elements, it is preferable to contain one or more elements selected from carbon, fluorine and hydrogen. The nitrogen-containing layer preferably has an oxygen content of 10 atom% or less, more preferably 5 atom% or less, and does not positively contain oxygen (composition by X-ray photoelectron spectroscopy or the like). It is more preferable that the lower limit of detection is not exceeded when the analysis is performed. When the oxygen content of the nitrogen-containing layer is large, the difference in optical characteristics between the nitrogen-containing layer and the oxygen-containing layer is small, and the degree of freedom in designing the phase shift film is small.

The nitrogen-containing layer may contain a noble gas. The noble gas is an element capable of increasing the film forming rate and improving the productivity by existing in the film forming chamber when forming the nitrogen-containing layer by reactive sputtering. When the noble gas is turned into plasma and collides with the target, target constituent elements fly out from the target, and a nitrogen-containing layer is formed on the translucent substrate 1 while taking in the reactive gas. A slight amount of the noble gas in the film forming chamber is taken in until the target constituent element jumps out of the target and adheres to the transparent substrate 1. Preferred noble gases required for this reactive sputtering include argon, krypton, and xenon. Further, in order to relieve the stress in the nitrogen-containing layer, helium or neon having a small atomic weight can be positively incorporated into the thin film.

The nitrogen-containing layer preferably has a nitrogen content of 50 atomic% or more. The silicon-based film has a very small refractive index n with respect to ArF exposure light and a large extinction coefficient k with respect to ArF exposure light (hereinafter, simply referred to as a refractive index n, means the refractive index n with respect to ArF exposure light). In other words, when simply referred to as an extinction coefficient k, it means the extinction coefficient k for ArF exposure light.). As the content of nitrogen in the silicon-based film increases, the refractive index n tends to increase and the extinction coefficient k tends to decrease. Considering securing the phase difference with a smaller thickness while securing the predetermined transmittance required for the phase shift film 2, it is preferable that the nitrogen content of the nitrogen-containing layer is 50 atomic% or more, It is more preferably 51 atomic% or more and even more preferably 52 atomic% or more. The nitrogen content of the nitrogen-containing layer is preferably 57 atom% or less, and more preferably 56 atom% or less. If it is attempted to make the nitrogen-containing layer contain more nitrogen than the mixing ratio of Si ₃ N ₄ , it becomes difficult to make the nitrogen-containing layer have an amorphous or microcrystalline structure. Moreover, the surface roughness of the nitrogen-containing layer is significantly deteriorated.

The nitrogen-containing layer preferably has a silicon content of 35 atomic% or more, more preferably 40 atomic% or more, and further preferably 45 atomic% or more.

The nitrogen-containing layer is preferably formed of a material composed of silicon and nitrogen. The material composed of silicon and nitrogen in this case can be regarded as including a material containing a noble gas.

The nitrogen-containing layer is subjected to X-ray photoelectron spectroscopic analysis to obtain the maximum peak PSi_f of the photoelectron intensity of the Si2p narrow spectrum in the nitrogen-containing layer, and the translucent substrate 1 is subjected to X-ray photoelectron spectroscopic analysis to obtain translucency. When the maximum peak PSi_s of the photoelectron intensity of the Si 2p narrow spectrum in the substrate 1 is acquired, the numerical value (PSi_f)/(PSi_s) obtained by dividing the maximum peak PSi_f in the nitrogen-containing layer by the maximum peak PSi_s in the transparent substrate 1 is 1.09. The following is preferable. As described above, the nitrogen-containing layer whose numerical value (PSi_f)/(PSi_s) is 1.09 or less is difficult to be excited even when it is irradiated with ArF exposure light. With such a nitrogen-containing layer, ArF light resistance can be improved. Further, in the nitrogen-containing layer, as described above, the existence ratio of the bond between nitrogen and silicon in the strongly bonded state is high. Moreover, chemical resistance can be improved by using such a nitrogen-containing layer. The numerical value (PSi_f)/(PSi_s) is preferably 1.085 or less, and more preferably 1.08 or less.

On the other hand, in the case of dry etching using a fluorine-based gas such as SF ₆ performed when patterning the phase shift film 2, the nitrogen-containing layer has a faster etching rate than the oxygen-containing layer. Therefore, when the phase shift film 2 is patterned by dry etching, a step tends to occur on the side wall of the pattern.

When patterning the nitrogen-containing layer by dry etching with the fluorine-based gas described above, the fluorine gas in the excited state cuts the bond between nitrogen and silicon, and produces a fluoride of silicon having a relatively low boiling point to volatilize, A pattern is formed in the nitrogen-containing layer. In the nitrogen-containing layer having a numerical value (PSi_f)/(PSi_s) of 1.09 or less, it can be said that the etching rate of dry etching with respect to the fluorine-based gas becomes slow because the bond between nitrogen and silicon is hard to break. Thereby, the etching rate difference between the nitrogen-containing layer and the oxygen-containing layer of the phase shift film 2 becomes small, and the step difference on the side wall of the pattern formed on the phase shift film 2 by dry etching can be reduced.

On the other hand, as a mask defect correction technique for a halftone type phase shift mask, by supplying xenon difluoride (XeF ₂ ) gas to the black defect portion of the phase shift film while irradiating the portion with an electron beam. A defect repair technique of changing the black defect portion into a volatile fluoride and removing it by etching (hereinafter, such defect repair performed by irradiating charged particles such as an electron beam is simply referred to as EB defect repair) is used. Sometimes. When EB defect correction is performed on the phase shift film 2 after the transfer pattern is formed, the correction rate of the nitrogen-containing layer tends to be faster than the correction rate of the oxygen-containing layer. In addition, in the case of EB defect correction, since the pattern of the phase shift film 2 in which the sidewall is exposed is etched, the side etching, which is the etching that proceeds in the sidewall direction of the pattern, is particularly likely to enter the nitrogen-containing layer. .. Therefore, the pattern shape after the EB defect correction tends to be a step shape that creates a step between the nitrogen-containing layer and the oxygen-containing layer.

XeF ₂ gas used for EB defect correction is known as an etching gas in a non-excited state when performing isotropic etching on a silicon-based material. The etching is performed by a process of surface adsorption of a non-excited state XeF ₂ gas on a silicon-based material, separation into Xe and F, generation of a higher fluoride of silicon, and volatilization. In the EB defect correction for a thin film pattern of a silicon-based material, a non-excited fluorine-based gas such as XeF ₂ gas is supplied to the black defect portion of the thin film pattern, and the fluorine-based gas is adsorbed on the surface of the black defect portion. Then, the black defect portion is irradiated with an electron beam. As a result, the silicon atom in the black defect portion is excited to promote the bond with fluorine, and volatilizes into a higher fluoride of silicon much faster than in the case where the electron beam is not irradiated. It can be said that the nitrogen-containing layer, which has a small number of photoelectrons emitted when irradiated with X-rays and is hard to be excited, is a material which is hard to be excited even when it is irradiated with an electron beam.

The nitrogen-containing layer having the above numerical value (PSi_f)/(PSi_s) of 1.09 or less is hard to be excited by electron beam irradiation, and the correction rate when EB defect correction is performed can be delayed. .. As a result, the difference in correction rate between the nitrogen-containing layer and the oxygen-containing layer of the phase shift film 2 in the EB defect correction becomes small, and the step difference on the side wall of the pattern at the position where the EB defect correction of the phase shift film 2 is performed can be reduced. it can.

In the above X-ray photoelectron spectroscopic analysis, as the X-rays with which the transparent substrate 1 and the nitrogen-containing layer are irradiated, both AlKα rays and MgKα rays can be applied, but AlKα rays are preferably used. In this specification, the case of performing X-ray photoelectron spectroscopic analysis using AlKα X-rays is described.

The method of performing the X-ray photoelectron spectroscopy analysis on the transparent substrate 1 and the nitrogen-containing layer to acquire the Si2p narrow spectrum is generally performed by the following procedure. That is, first, a wide spectrum is acquired by performing a wide scan to acquire the photoelectron intensity (the number of photoelectrons emitted from the measurement object irradiated with X-rays per unit time) with a wide band of binding energy, and the transmission spectrum is acquired. All peaks derived from the constituent elements of the optical substrate 1 and the nitrogen-containing layer are identified. Then, each narrow spectrum is acquired by performing a narrow scan, which has a higher resolution than the wide scan but has a narrow band width of the binding energy that can be acquired, with a band width around the peak (Si2p) of interest. On the other hand, the constituent elements of the transparent substrate 1 and the nitrogen-containing layer, which are the objects to be measured using X-ray photoelectron spectroscopy in the present invention, are known in advance. Further, the narrow spectrum required in the present invention is limited to the Si2p narrow spectrum. Therefore, in the case of the present invention, the step of acquiring the wide spectrum may be omitted and the Si2p narrow spectrum may be acquired.

The maximum peak (PSi_f, PSi_s) of the photoelectron intensity in the Si2p narrow spectrum obtained by performing the X-ray photoelectron spectroscopy analysis on the transparent substrate 1 and the nitrogen-containing layer has a binding energy of 96 [eV] or more and 106 [eV] or more. ] It is preferable that the maximum peak is in the following range. This is because the peak outside the range of the binding energy may not be the photoelectrons emitted from the Si—N bond or the Si—O bond.

In the nitrogen-containing layer, the number of Si ₃ N ₄ bonds present is changed to Si ₃ N ₄ bonds, Si _a N _b bonds (where b/[a+b]<4/7), Si—Si bonds, Si—O bonds and The ratio divided by the total number of Si-ON bonds present is preferably 0.88 or more. The nitrogen-containing layer in which the existence ratio of stable bonds is high has high ArF light resistance and chemical resistance. Among the above bonds, the Si—O bond is the most stable bond, but it is difficult to make the nitrogen-containing layer contain a large amount of oxygen because of the above restrictions. Among the bonds with silicon other than oxygen, the Si ₃ N ₄ bond is the most stable bond, and the nitrogen-containing layer having a high Si ₃ N ₄ bond ratio as described above has ArF light resistance and chemical resistance. high.

The total thickness of all the nitrogen-containing layers provided in the phase shift film 2 is preferably 30 nm or more. If the total film thickness of all the nitrogen-containing layers is less than 30 nm, the predetermined transmittance (40% or less) and phase difference (150 degrees or more and 200 degrees or less) required for the phase shift film may not be obtained. .. The total film thickness of all the nitrogen-containing layers is more preferably 35 nm or more, further preferably 40 nm or more. On the other hand, the total film thickness of all the nitrogen-containing layers provided in the phase shift film 2 is preferably 60 nm or less, and more preferably 55 nm or less.

The oxygen-containing layer 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 non-metal elements, and oxygen and silicon. The oxygen-containing layer may contain any metalloid element in addition to silicon. Among these semi-metal elements, it is preferable to contain 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.

The oxygen-containing layer may contain any non-metal element in addition to oxygen. In this case, the non-metal element includes a non-metal element in a narrow sense (nitrogen, carbon, oxygen, phosphorus, sulfur, selenium), halogen and noble gas. Among these non-metal elements, it is preferable to contain one or more elements selected from carbon, fluorine and hydrogen. The oxygen-containing layer may contain a noble gas for the same reason as the nitrogen-containing layer.

The oxygen-containing layer preferably has a total content of nitrogen and oxygen of 50 atomic% or more. Considering increasing the degree of freedom in designing the phase shift film 2 (particularly the transmittance), the total content of nitrogen and oxygen in the oxygen-containing layer is preferably 50 atomic% or more, and 55 atomic% or more. More preferably, it is more preferably 60 atomic% or more. The total content of nitrogen and oxygen in the oxygen-containing layer is preferably 66 atom% or less. If the nitrogen-containing layer is made to contain nitrogen and oxygen in an amount larger than the mixing ratio of SiO ₂ and Si ₃ N ₄ , it becomes difficult to make the oxygen-containing layer have an amorphous or microcrystalline structure. Moreover, the surface roughness of the oxygen-containing layer is significantly deteriorated.

The oxygen-containing layer is preferably formed of a material composed of silicon, nitrogen and oxygen. In particular, when the degree of freedom in designing the phase shift film is widened in a region having high transmittance, the oxygen-containing layer may be formed of a material composed of silicon and oxygen. It should be noted that the material composed of silicon, nitrogen and oxygen and the material composed of silicon and oxygen in these cases can be regarded as including a material containing a noble gas.

The oxygen-containing layer preferably has an oxygen content of 15 atomic% or more. The extinction coefficient k of the silicon-based film becomes significantly smaller as the content of oxygen increases, as compared with the case of increasing the content of nitrogen. When the degree of design freedom of the phase shift film is widened in a region having high transmittance, the oxygen content of the oxygen-containing layer is preferably 15 atom% or more, more preferably 20 atom% or more, and 25 atom% or more. It is more preferable that it is above.

The total film thickness of all oxygen-containing layers provided in the phase shift film 2 is preferably 10 nm or more, more preferably 15 nm or more, and further preferably 20 nm or more. On the other hand, the total film thickness of all oxygen-containing layers provided in the phase shift film 2 is preferably 50 nm or less, and more preferably 45 nm or less.

It is most preferable that the nitrogen-containing layer and the oxygen-containing layer have an amorphous structure because, for example, the pattern edge roughness becomes good when a pattern is formed by etching. When the nitrogen-containing layer and the oxygen-containing layer have a composition that makes it difficult to form an amorphous structure, it is preferable that the amorphous structure and the microcrystalline structure are mixed.

The refractive index n of the nitrogen-containing layer is preferably 2.3 or more, more preferably 2.4 or more. Further, the nitrogen-containing layer preferably has an extinction coefficient k for ArF exposure light of 0.5 or less, and more preferably 0.4 or less. On the other hand, the nitrogen-containing layer preferably has a refractive index n of 3.0 or less, more preferably 2.8 or less. The extinction coefficient k of the nitrogen-containing layer is preferably 0.16 or more, more preferably 0.2 or more.

The oxygen-containing layer preferably has a refractive index n of 1.5 or more, and more preferably 1.8 or more. The oxygen-containing layer preferably has an extinction coefficient k for ArF exposure light of 0.15 or less, and more preferably 0.1 or less. On the other hand, the oxygen-containing layer preferably has a refractive index n of 2.2 or less, and more preferably 1.9 or less. The extinction coefficient k of the oxygen-containing layer is preferably 0 or more.

The refractive index n and the extinction coefficient k of a thin film 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, various conditions for forming a thin film by reactive sputtering are adjusted so that the thin film has a desired refractive index n and extinction coefficient k. In order to make the nitrogen-containing layer and the oxygen-containing layer within the desired ranges of the refractive index n and the extinction coefficient k, when forming a thin film by reactive sputtering, the ratio of the mixed gas of noble gas and reactive gas is set. It is not limited to adjusting. The pressure in the film forming chamber when forming a thin film by reactive sputtering, the power applied to the target, the positional relationship such as the distance between the target and the transparent substrate, and the like are wide-ranging. Further, these film forming conditions are peculiar to the film forming apparatus and are appropriately adjusted so that the formed thin film has a desired refractive index n and extinction coefficient k.

The nitrogen-containing layer and the oxygen-containing layer are formed by sputtering, but any sputtering such as DC sputtering, RF sputtering and ion beam sputtering can be applied. In the case of using a target having low conductivity (silicon target, a silicon compound target that does not contain a metalloid element or has a small content), it is preferable to apply RF sputtering or ion beam sputtering, but the film formation rate is taken into consideration. Then, it is more preferable to apply RF sputtering.

When the film stress of the phase shift film 2 is large, there arises a problem that the position shift of the transfer pattern formed on the phase shift film 2 becomes large when the phase shift mask is manufactured from the mask blank. The film stress of the phase shift film 2 is preferably 275 MPa or less, more preferably 165 MPa or less, and further preferably 110 MPa or less. The phase shift film 2 formed by the above-mentioned sputtering has a relatively large film stress. Therefore, it is preferable to reduce the film stress of the phase shift film 2 by subjecting the phase shift film 2 formed by sputtering to heat treatment, light irradiation treatment using a flash lamp or the like.

In the mask blank 100, the light shielding film 3 is preferably provided on the phase shift film 2. Generally, in the phase shift mask 200 (see FIG. 2F), the outer peripheral area of the area where the transfer pattern is formed (transfer pattern forming area) is exposed and transferred to a resist film on a semiconductor wafer by using an exposure device. It is required to secure an optical density (OD) of a predetermined value or more so that the resist film is not affected by the exposure light transmitted through the outer peripheral region. At least in the outer peripheral region of the phase shift mask 200, the optical density is required to be higher than 2.0. As described above, the phase shift film 2 has a function of transmitting exposure light at a predetermined transmittance, and it is difficult to secure the above optical density only with the phase shift film 2. For this reason, it is desired that the light-shielding film 3 be laminated on the phase shift film 2 at the stage of manufacturing the mask blank 100 in order to secure the insufficient optical density. With such a structure of the mask blank 100, when the phase shift film 2 is manufactured, the light-shielding film 3 in the region where the phase shift effect is used (basically the transfer pattern forming region) is removed. In addition, the phase shift mask 200 in which the above optical density is secured can be manufactured. In the mask blank 100, the optical density in the laminated structure of the phase shift film 2 and the light shielding film 3 is preferably 2.5 or more, more preferably 2.8 or more. In order to reduce the thickness of the light shielding film 3, it is preferable that the laminated structure of the phase shift film 2 and the light shielding film 3 has an optical density of 4.0 or less.

The light-shielding film 3 may have a single-layer structure or a laminated structure of two or more layers. In addition, 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 may have substantially the same composition in the thickness direction of the film or layers, and may have the same composition in the thickness direction of the layers. The composition may be graded.

The light-shielding film 3 is made of a material having sufficient etching selectivity with respect to an etching gas used when forming a pattern on the phase shift film 2 when another film is not interposed between the light-shielding film 3 and the phase shift film 2. Need to apply. In this case, the light shielding film 3 is preferably made of a material containing chromium. As a material containing chromium forming the light-shielding film 3, in addition to chromium metal, a material containing one or more elements selected from oxygen, nitrogen, carbon, boron and fluorine in chromium can be mentioned.

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

On the other hand, in the mask blank 100, when another film is interposed between the light-shielding film 3 and the phase shift film 2, the other film (etching stopper/etching mask film) made of the above-mentioned material containing chromium is used. ) Is formed, and the light-shielding film 3 is formed of a material containing silicon. A material containing chromium is etched by a mixed gas of chlorine-based gas and oxygen gas, but a resist film formed of an organic-based material is easily etched by this mixed gas. A material containing silicon is generally etched with a fluorine-based gas or a chlorine-based gas. Since these etching gases basically do not contain oxygen, the reduction amount of the resist film formed of an organic material can be reduced as compared with the case of etching with a mixed gas of chlorine-based gas and oxygen gas. Therefore, the thickness of the resist film can be reduced.

The material containing silicon forming the light-shielding film 3 may contain a transition metal or a metal element other than the transition metal. This is because when the phase shift mask 200 is manufactured from this mask blank 100, the pattern formed by the light-shielding film 3 is basically a light-shielding band pattern in the outer peripheral region, and the ArF exposure light is higher than that in the transfer pattern forming region. This is because the integrated amount of irradiation is small and the light-shielding film 3 rarely remains in a fine pattern, and even if the ArF light resistance is low, a substantial problem hardly occurs. Further, when the light-shielding film 3 contains a transition metal, the light-shielding performance is greatly improved as compared with the case where the light-shielding film 3 is not contained, and the thickness of the light-shielding film 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), vanadium (V). Examples thereof include any one metal of zirconium (Zr), ruthenium (Ru), rhodium (Rh), niobium (Nb), palladium (Pd), and alloys of these metals.

On the other hand, as the silicon-containing material forming the light-shielding film 3, a material containing silicon and nitrogen, or a material containing one or more elements selected from semi-metal elements and non-metal elements in the material containing silicon and nitrogen is applied. You may.

In the mask blank 100 including the light shielding film 3 laminated on the phase shift film 2, the mask blank 100 is formed of a material having etching selectivity with respect to the etching gas used when the light shielding film 3 is etched on the light shielding film 3. More preferably, the hard mask film 4 is further laminated. Since the light-shielding film 3 has an essential function of ensuring a predetermined optical density, there is a limit in reducing the thickness thereof. It suffices for the hard mask film 4 to have a film thickness that can function as an etching mask until the dry etching for forming a pattern on the light-shielding film 3 immediately below the hard mask film 4 is completed. Not subject to the restrictions of. Therefore, the thickness of the hard mask film 4 can be made significantly smaller than the thickness of the light shielding film 3. Since the resist film made of an organic material needs to have a film thickness sufficient to function as an etching mask until the dry etching for forming a pattern on the hard mask film 4 is completed, it is more than conventional. The thickness of the resist film can be greatly reduced.

When the light-shielding film 3 is made of a material containing chromium, the hard mask film 4 is preferably made of the above-mentioned material containing silicon. Since the hard mask film 4 in this case tends to have low adhesiveness to the resist film of an organic material, the surface of the hard mask film 4 is subjected to HMDS (Hexamethyldisilane) treatment to improve the adhesiveness of the surface. It is preferable. The hard mask film 4 in this case is more preferably formed of SiO ₂ , SiN, SiON, or the like. Further, 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 is also applicable in addition to the above. Examples of the material containing tantalum in this case include tantalum metal, and materials containing tantalum containing one or more elements selected from nitrogen, oxygen, boron and carbon. Examples of the material include Ta, TaN, TaON, TaBN, TaBON, TaCN, TaCON, TaBCN, TaBOCN and the like. On the other hand, when the light-shielding film 3 is made of a material containing silicon, the hard mask film 4 is preferably made of the above-mentioned material containing chromium.

In the mask blank 100, it is preferable that a resist film of an organic material having a film thickness of 100 nm or less is formed in contact with the surface of the hard mask film 4. In the case of a fine pattern corresponding to the DRAM hp 32 nm generation, a transfer pattern (phase shift pattern) to be formed on the hard mask film 4 may be provided with SRAF (Sub-Resolution Assist Feature) having a line width of 40 nm. However, even in this case, since the cross-sectional aspect ratio of the resist pattern can be made as low as 1:2.5, it is possible to prevent the resist pattern from being collapsed or detached at the time of developing or rinsing the resist film. it can. It is more preferable that the resist film has a film thickness of 80 nm or less.

FIG. 2 shows a schematic sectional view of a step of manufacturing the phase shift mask 200 from the mask blank 100 according to the embodiment of the present invention.

A phase shift mask 200 of the present invention is a phase shift mask 200 including a phase shift film 2 having a transfer pattern formed on a transparent substrate 1, and the phase shift film 2 (phase shift pattern 2a) is nitrogen. At least a containing layer and an oxygen-containing layer, the oxygen-containing 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 non-metal elements, and oxygen and silicon, The nitrogen-containing layer is formed of a material composed of silicon and nitrogen, or a material composed of one or more elements selected from non-metal elements and metalloid elements, and nitrogen and silicon. X-ray photoelectron spectroscopy is applied to the nitrogen-containing layer. The maximum peak PSi_f of the photoelectron intensity of the Si2p narrow spectrum in the nitrogen-containing layer is obtained by performing an analysis, and the X-ray photoelectron spectroscopy analysis is performed on the transparent substrate 1 to obtain the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate 1. Is obtained by dividing the maximum peak PSi_f in the nitrogen-containing layer by the maximum peak PSi_s in the light-transmissive substrate when the maximum peak PSi_s is obtained (PSi_f)/(PSi_s) is 1.09 or less. is there.

The phase shift mask 200 has the same technical characteristics as the mask blank 100. The matters relating to the transparent substrate 1, the phase shift film 2 and the light shielding film 3 in the phase shift mask 200 are the same as those in the mask blank 100. In such a phase shift mask 200, the ArF light resistance of the entire phase shift film 2 (phase shift pattern 2a) is improved, and the chemical resistance is also improved. Therefore, even when the phase shift mask 200 is set on the mask stage of an exposure apparatus that uses ArF excimer laser as exposure light and the phase shift pattern 2a is exposed and transferred to the resist film on the semiconductor device, the resist film on the semiconductor device is also transferred. In addition, it is possible to transfer the pattern with sufficient accuracy to meet the design specifications.

An example of a method of manufacturing the phase shift mask 200 will be described below according to the manufacturing process shown in FIG. In this example, the light-shielding film 3 is made of a material containing chromium, and the hard mask film 4 is made of a material containing silicon.

First, a resist film was formed by a spin coating method in contact with the hard mask film 4 in the mask blank 100. 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, and a predetermined process such as a developing process is further performed to form the phase shift pattern. A first resist pattern 5a having the above is formed (see FIG. 2A). Then, dry etching using a fluorine-based gas was performed using the first resist pattern 5a as a mask to form a first pattern (hard mask pattern 4a) on the hard mask film 4 (see FIG. 2B). ..

Next, after removing the resist pattern 5a, dry etching using a mixed gas of chlorine-based gas and oxygen gas is performed using the hard mask pattern 4a as a mask, and the first pattern (the light-shielding pattern 3a is formed on the light-shielding film 3). ) Is formed (see FIG. 2C). Then, using the light-shielding pattern 3a as a mask, dry etching using a fluorine-based gas is performed to form a first pattern (phase shift pattern 2a) on the phase shift film 2, and at the same time, the hard mask pattern 4a is also removed ( See FIG. 2D).

Next, a resist film was formed on the mask blank 100 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, and a predetermined process such as a developing process is further performed to form a second light-shielding pattern. A resist pattern 6b was formed. Then, using the second resist pattern 6b as a mask, dry etching was performed using a mixed gas of chlorine-based gas and oxygen gas to form a second pattern (light-shielding pattern 3b) on the light-shielding film 3 (FIG. 2). (See (E)). Further, the second resist pattern 6b was removed, and predetermined processing such as cleaning was performed to obtain a phase shift mask 200 (see FIG. 2F).

The chlorine-based gas used in the above dry etching is not particularly limited as long as it contains Cl. For example, examples of chlorine-based gas include Cl ₂ , SiCl ₂ , CHCl ₃ , CH ₂ Cl ₂ , CCl ₄ , BCl _{3 and the} like. Further, the fluorine-based gas used in the above dry etching is not particularly limited as long as it contains F. For example, a fluorine-based _{gas, CHF 3, CF 4, C} 2 F 6, C 4 F 8, SF 6 , and the like. In particular, since the fluorine-based gas containing no C has a relatively low etching rate of the glass material with respect to the transparent substrate 1, the damage to the transparent substrate 1 can be further reduced.

Further, the method for manufacturing a semiconductor device of the present invention is characterized in that the pattern is exposed and transferred onto a resist film on a semiconductor substrate by using the phase shift mask 200 manufactured by using the mask blank 100. Since the mask blank 100 of the present invention and the phase shift mask 200 manufactured using the mask blank 100 have the effects as described above, the phase shift mask is used for the mask stage of the exposure apparatus using ArF excimer laser as the exposure light. Even when 200 is set and the phase shift pattern 2a is exposed and transferred to the resist film on the semiconductor device, the pattern can be transferred to the resist film on the semiconductor device with sufficient accuracy to meet design specifications.

On the other hand, as another embodiment related to the present invention, a mask blank having the following configuration can be given. That is, the mask blank of the another embodiment is provided with a phase shift film on a transparent substrate, and the phase shift film contains oxygen on the surface on the side opposite to the transparent substrate and the region in the vicinity thereof. The phase shift film is a single layer film having a compositionally graded portion in which the amount is increased, and the phase shift film is made of a material composed of silicon and nitrogen, or one or more elements selected from a non-metal element and a metalloid element, and nitrogen and silicon. X-ray photoelectron spectroscopy analysis is performed on the phase shift film formed of a material to obtain the maximum peak PSi_f of photoelectron intensity of Si2p narrow spectrum in the phase shift film, and X-ray photoelectron spectroscopy analysis is performed on the transparent substrate. When the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is obtained by performing the calculation, the maximum peak PSi_f in the phase shift film is divided by the maximum peak PSi_s in the transparent substrate (PSi_f)/(PSi_s). It is characterized by being 1.09 or less.

The region of the phase shift film excluding the composition gradient portion has the same characteristics as the nitrogen-containing layer of the phase shift film of the present invention. Further, the compositionally graded portion of the phase shift film has high ArF light resistance and chemical resistance because the oxygen content is large. Therefore, the mask blank of this another embodiment has a higher ArF light resistance as a whole of the phase shift film and a higher chemical resistance than the mask blank including the phase shift film made of the conventional silicon nitride-based material having a single-layer structure. It is also very popular. Note that other matters regarding the phase shift film of the other embodiment are the same as those of the nitrogen-containing layer in the phase shift film of the embodiment of the present invention.

Further, a phase shift mask of another embodiment having the same characteristics as the mask blank of the other embodiment described above can also be mentioned. That is, the phase shift mask of the another embodiment includes a phase shift film having a transfer pattern formed on a transparent substrate, and the phase shift film includes a surface opposite to the transparent substrate and its surface. The phase shift film is a single-layer film having a composition gradient portion with an increased oxygen content in a nearby region, and the phase shift film is a material composed of silicon and nitrogen, or one or more elements selected from non-metal elements and metalloid elements. X-ray photoelectron spectroscopy analysis is performed on the phase shift film, which is formed of a material composed of nitrogen, silicon and silicon, and the maximum peak PSi_f of the photoelectron intensity of the Si2p narrow spectrum in the phase shift film is obtained. When the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate was obtained by performing X-ray photoelectron spectroscopy analysis, the maximum peak PSi_f in the phase shift film was divided by the maximum peak PSi_s in the transparent substrate ( It is characterized in that PSi_f)/(PSi_s) is 1.09 or less.

As in the case of the mask blank of the above-described another embodiment, the phase shift mask of this other embodiment has a phase shift mask as compared with the phase shift mask including the phase shift film made of the silicon nitride-based material of the conventional single layer structure. The ArF light resistance of the entire shift film is high and the chemical resistance is high. Also, when the phase shift mask of this other embodiment is set on the mask stage of the exposure apparatus using ArF excimer laser as the exposure light and the phase shift pattern is exposed and transferred to the resist film on the semiconductor device, the phase shift mask on the semiconductor device is also exposed. The pattern can be transferred onto the resist film with sufficient accuracy to meet the design specifications.

Hereinafter, the embodiment of the present invention will be described more specifically by way of 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 6.25 mm was prepared. The light-transmissive substrate 1 had its end face and main surface polished to a predetermined surface roughness, and then subjected to a predetermined cleaning treatment and drying treatment.

Next, a phase shift film 2 having a two-layer structure in which a nitrogen-containing layer and an oxygen-containing layer were laminated was formed on the transparent substrate 1 by the following procedure. First, the translucent substrate 1 is installed in a single-wafer RF sputtering apparatus, a silicon (Si) target is used, and a mixed gas of krypton (Kr), helium (He), and nitrogen (N ₂ ) is used as a sputtering gas, A nitrogen-containing layer (silicon nitride layer) of the phase shift film 2 made of silicon and nitrogen was formed to a thickness of 58 nm on the transparent substrate 1 by reactive sputtering (RF sputtering) with an RF power source.

Subsequently, the translucent substrate 1 is set in a single-wafer RF sputtering apparatus, a silicon dioxide (SiO ₂ ) target is used, and argon (Ar) gas is used as a sputtering gas, and reactive sputtering (RF sputtering) is performed by an RF power source. Thus, the oxygen-containing layer (silicon oxide layer) of the phase shift film 2 made of silicon and oxygen was formed on the nitrogen-containing layer to a thickness of 11 nm.

Next, the translucent substrate 1 on which the phase shift film 2 was formed was placed in an electric furnace and heat-treated in the atmosphere under the conditions of a heating temperature of 550° C. and a treatment time of 1 hour. The electric furnace used had the same structure as the vertical furnace disclosed in FIG. 5 of JP-A-2002-162726. The heat treatment in the electric furnace was carried out in a state where the atmosphere passed through the chemical filter was introduced into the furnace. After the heat treatment in the electric furnace, a coolant was injected into the electric furnace to perform forced cooling to the predetermined temperature (about 250° C.) on the substrate. This forced cooling was performed in a state where nitrogen gas as a refrigerant was introduced into the furnace (substantially a nitrogen gas atmosphere). After the forced cooling, the substrate was taken out of the electric furnace and naturally cooled in the atmosphere until the temperature dropped to room temperature (25° C. or lower).

The transmittance and the phase difference at the wavelength of the light of the ArF excimer laser (about 193 nm) and the phase difference were measured with respect to the phase shift film 2 after the heat treatment with a phase shift amount measuring device (MPM-193 manufactured by Lasertec Corporation). 21% and the phase difference was 177 degrees. In addition, after forming a phase shift film on the main surface of another transparent substrate under the same conditions and further performing heat treatment under the same conditions, a spectroscopic ellipsometer (M-2000D manufactured by JA Woollam Co., Ltd.). ) Was used to measure the optical characteristics of this phase shift film. As a result, the nitrogen-containing layer has a refractive index n of 2.56 at a wavelength of 193 nm and an extinction coefficient k of 0.35, and the oxygen-containing layer has a refractive index n of 1.59 at a wavelength of 193 nm and an extinction coefficient k. Was 0.00.

Next, another phase shift film was formed on the main surface of another translucent substrate under the same film forming conditions as those of the phase shift film 2 of Example 1 above, and heat treatment was further performed under the same conditions. Next, X-ray photoelectron spectroscopy analysis was performed on the other transparent substrate and the phase shift film after the heat treatment. In this X-ray photoelectron spectroscopy analysis, the surface of the phase shift film (also the transparent substrate) is irradiated with X-rays (AlKα ray: 1486 eV) to measure the intensity of photoelectrons emitted from the phase shift film, The surface of the phase shift film (or the translucent substrate) is dug by Ar gas sputtering for a predetermined time (about 0.7 nm depth), and the phase shift film (or the translucent substrate) in the dug region is etched. The Si2p narrow spectrum was acquired for each of the phase shift film and the transparent substrate by repeating the step of irradiating the X-ray and measuring the intensity of the photoelectrons emitted from the phase shift film in the engraved region. The acquired Si2p narrow spectrum has a lower energy than the spectrum when analyzed on a conductor because the transparent substrate 1 is an insulator. In order to correct this displacement, correction is made according to the peak of carbon, which is a conductor. In this X-ray photoelectron spectroscopic analysis, AlKα rays (1486.6 eV) were used as X-rays, the photoelectron detection region was 200 μmφ, and the extraction angle was 45 deg (the same applies to the following Comparative Examples).

FIG. 3 shows the Si2p narrow spectra of the nitrogen-containing layer (silicon nitride layer) of the phase shift film and the transparent substrate. From the result of this X-ray photoelectron spectroscopy analysis, a value obtained by dividing the maximum peak PSi_f of the Si2p narrow spectrum in the nitrogen-containing layer of the phase shift film by the maximum peak PSi_s of the Si2p narrow spectrum in the transparent substrate (PSi_f)/(PSi_s) Was calculated to be 1.077.

The Si2p narrow spectrum of the obtained nitrogen-containing layer, containing _Si 3 _{N 4} bond, _Si a _{N b} binding (b / [a + b] <4/7), a peak of Si-O bonds and Si-ON bond, respectively Has been. Then, the peak positions of the Si ₃ N ₄ bond, the Si _a N _b bond, the Si—O bond, and the Si—ON bond (however, the Si—O bond and the Si—ON bond are the same peak position) and the half value. Peak separation was carried out while fixing the full width at half maximum (FWHM). Specifically, the peak position of the Si _a N _b bond is 100.4 eV, the peak position of the Si ₃ N ₄ bond is 102.0 eV, and the peak positions of the Si—O bond and the Si—ON bond are 103.3 eV. The peak separation was performed with the full width at half maximum FWHM of each set to 2.06 (the same applies to Comparative Example 1 below).

Further, the peak-separated spectra of Si _a N _b bond, Si ₃ N ₄ bond, and Si—O bond and Si—ON bond were calculated by an algorithm of a known method provided in the analyzer. The areas subtracted from the background were calculated, and the ratio of the number of Si _a N _b bonds present and the ratio of the number of Si ₃ N ₄ bonds present were calculated based on the calculated areas. Each was calculated. As a result, the abundance ratio of Si _a N _b bonds was 0.092, the abundance ratio of Si ₃ N ₄ bonds was 0.884, and the abundance ratio of Si—O bonds and Si—ON bonds was 0. It was 024. That is, the nitrogen-containing layer, the existence number the _Si 3 _{N 4} bond, _Si 3 _{N 4} bond, _Si a _{N b} binding ratio obtained by dividing the total number of existing Si-O bond and Si-ON bond 0.88 The above conditions were satisfied (satisfied with 0.884). From the result of this X-ray photoelectron spectroscopy analysis, the composition of the nitrogen-containing layer of this phase shift film was Si:N:O=43.6 atom%:55.2 atom%:1.2 atom %, It was found that the composition of the oxygen-containing layer was Si:O=33.8 atomic%:66.2 atomic %.

Next, the translucent substrate 1 on which the phase shift film 2 after the heat treatment is formed is placed in a single-wafer type DC sputtering apparatus, and a chromium (Cr) target is used, and argon (Ar), carbon dioxide (CO ₂ ) And helium (He) mixed gas (flow ratio Ar:CO ₂ :He=18:33:28, pressure=0.15 Pa) was used as the sputtering gas, the power of the DC power supply was set to 1.8 kW, and the reactive sputtering was performed. By (DC sputtering), a light shielding film 3 made of CrOC was formed in a thickness of 56 nm in contact with the surface of the phase shift film 2.

Further, the translucent substrate 1 on which the phase shift film 2 and the light shielding film 3 are stacked is installed in a single-wafer RF sputtering apparatus, a silicon dioxide (SiO ₂ ) target is used, and an argon (Ar) gas (pressure= 0.03 Pa) was used as the sputtering gas, the power of the RF power source was set to 1.5 kW, and the hard mask film 4 made of silicon and oxygen was formed to a thickness of 5 nm on the light shielding film 3 by RF sputtering. By the above procedure, the mask blank 100 having a structure in which the phase shift film 2, the light shielding film 3, and the hard mask film 4 were laminated on the transparent substrate 1 was manufactured.

[Manufacture of phase shift mask]
Next, using the mask blank 100 of Example 1, the phase shift mask 200 of Example 1 was manufactured by the following procedure. First, the surface of the hard mask film 4 was subjected to HMDS treatment. Subsequently, a resist film made of a chemically amplified resist for electron beam drawing having a film thickness of 80 nm was formed in contact with the surface of the hard mask film 4 by a spin coating method. Then, a first pattern, which is a phase shift pattern to be formed on the phase shift film 2, is electron beam-drawn on the resist film, and a predetermined developing process and cleaning process are performed to obtain a first pattern having the first pattern. A resist pattern 5a of No. 1 was formed (see FIG. 2A).

Next, using the first resist pattern 5a as a mask, dry etching was performed using CF ₄ gas to form a first pattern (hard mask pattern 4a) on the hard mask film 4 (see FIG. 2B). ..

Next, the first resist pattern 5a was removed. Then, using the hard mask pattern 4a as a mask, dry etching is performed using a mixed gas of chlorine and oxygen (gas flow rate ratio Cl ₂ :O ₂ =4:1), and the first pattern (light shielding film) is formed on the light shielding film 3. A pattern 3a) was formed (see FIG. 2C).

Next, using the light shielding pattern 3a as a mask, dry etching is performed using a fluorine-based gas (mixed gas of SF ₆ and He) to form a first pattern (phase shift pattern 2a) on the phase shift film 2, and At the same time, the hard mask pattern 4a was removed (see FIG. 2D).

Next, a resist film made of a chemically amplified resist for electron beam writing having a film thickness of 150 nm was formed on the light shielding pattern 3a 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, and a predetermined process such as a developing process is further performed to form a second light-shielding pattern. A resist pattern 6b was formed. Subsequently, using the second resist pattern 6b as a mask, dry etching is performed using a mixed gas of chlorine and oxygen (gas flow rate ratio Cl ₂ :O ₂ =4:1) to form the second pattern on the light-shielding film 3. (Light-shielding pattern 3b) was formed (see FIG. 2E). Further, the second resist pattern 6b was removed, and a cleaning process was performed to obtain a phase shift mask 200 (see FIG. 2F).

The phase shift pattern 2a of the manufactured halftone phase shift mask 200 of Example 1 was subjected to intermittent irradiation with ArF excimer laser light at an integrated irradiation amount of 40 kJ/cm ² . The CD change amount of the phase shift pattern 2a before and after the irradiation process was 1.2 nm at the maximum, which was a CD change amount capable of ensuring high transfer accuracy as the phase shift mask 200.

Further, the halftone type phase shift mask 200 of Example 1 was separately manufactured by the same procedure, and the phase shift mask 200 was subjected to cleaning treatment with a chemical solution. Specifically, the phase shift mask 200 is first subjected to SPM cleaning (cleaning liquid: H ₂ SO ₄ +H ₂ O ₂ ), then rinsed with DI (DeIonized) water, and then to APM cleaning (cleaning liquid. : NH ₄ OH+H ₂ O ₂ +H ₂ O), and finally a rinse step of rinsing with DI water was set as one cycle, and this cycle was repeated 20 cycles. The phase shift pattern 2a of the phase shift mask 200 after this cleaning process was observed with a cross-section TEM (Transmission Electron Microscope). As a result, the sidewall shape of the phase shift pattern 2a was confirmed to be good, and no conspicuous step was found between the silicon nitride layer and the silicon oxide layer.

Next, AIMS 193 (manufactured by Carl Zeiss) is used to expose and transfer the resist film on the semiconductor device to the resist film on the semiconductor device using AIMS 193 (manufactured by Carl Zeiss Co., Ltd.) with respect to the phase shift mask 200 of Example 1 after the integrated irradiation treatment with ArF excimer laser light. The simulation of the transferred image at that time was performed. When the exposure transfer image of this simulation was verified, the design specifications were sufficiently satisfied. From this result, even when the phase shift mask 200 of Example 1 after the integrated irradiation processing with ArF excimer laser light is set on the mask stage of the exposure apparatus and transferred to the resist film on the semiconductor device by exposure, the semiconductor device is finally obtained. It can be said that the circuit pattern can be formed on the top with high accuracy.

(Comparative Example 1)
[Manufacture of mask blanks]
The mask blank of Comparative Example 1 was manufactured by the same procedure as the mask blank 100 of Example 1, except that the conditions of the heat treatment for the phase shift film were changed. Specifically, the transparent substrate 1 on which the phase shift film 2 of Comparative Example 1 was formed was placed on a hot plate and heat-treated in the atmosphere under the conditions of a heating temperature of 280° C. and a treatment time of 30 minutes. .. After the heat treatment, forced cooling was performed using a refrigerant until the temperature dropped to room temperature (25° C. or lower).

When the transmittance and the phase difference at the wavelength of the light of ArF excimer laser (about 193 nm) and the phase difference were measured with respect to the phase shift film after the heat treatment with a phase shift amount measuring device (MPM-193 manufactured by Lasertec Corporation), the transmittance was 21. %, the phase difference was 177 degrees. Further, as in the case of Example 1, the optical characteristics of this phase shift film were measured. As a result, the nitrogen-containing layer has a refractive index n of 2.58 and an extinction coefficient k of 0.39 at a wavelength of 193 nm, and the oxygen-containing layer has a refractive index n of 1.59 and an extinction coefficient of k at a wavelength of 193 nm. Was 0.00.

Similar to the case of Example 1, another phase shift film was formed on the main surface of another translucent substrate under the same film forming conditions as the phase shift film of Comparative Example 1, and heat treatment was performed under the same conditions. went. Next, the same X-ray photoelectron spectroscopy analysis as in Example 1 was performed on the other transparent substrate and the phase shift film after the heat treatment.

FIG. 4 shows the respective Si2p narrow spectra of the nitrogen-containing layer (silicon nitride layer) of the phase shift film of Comparative Example 1 and the transparent substrate. From the result of this X-ray photoelectron spectroscopy analysis, a value obtained by dividing the maximum peak PSi_f of the Si2p narrow spectrum in the nitrogen-containing layer of the phase shift film by the maximum peak PSi_s of the Si2p narrow spectrum in the transparent substrate (PSi_f)/(PSi_s) Was calculated to be 1.096.

As in Example 1, Si2p narrow spectrum of the nitrogen-containing layer of this Comparative Example 1 with respect to, _Si 3 _{N 4} bond, _Si a _{N b} binding (b / [a + b] <4/7), Si-O The peaks of the bond and the Si-ON bond were separated, and the ratio of the number of each bond present was calculated. As a result, the abundance ratio of Si _a N _b bonds was 0.093, the abundance ratio of Si ₃ N ₄ bonds was 0.873, and the abundance ratio of Si—O bonds and Si—ON bonds was 0. It was 034. That is, the nitrogen-containing layer of this Comparative Example 1, the existence number the _Si 3 _{N 4} bond, _Si 3 _{N 4} bond, _Si a _{N b} binding was divided by the total number of existing Si-O bond and Si-ON bond The condition that the ratio was 0.88 or more was not satisfied (0.873 was not satisfied). From the result of the X-ray photoelectron spectroscopy analysis, the composition of the nitrogen-containing layer of the phase shift film of Comparative Example 1 was Si:N:O=43.8 atomic%:54.5 atomic%:1.7 atomic. %, and the composition of the oxygen-containing layer was found to be Si:O=33.9 atomic%:66.1 atomic %.

Next, as in the case of Example 1, a light-shielding film and a hard mask film were formed on the phase shift film of the translucent substrate. Through the above procedure, a mask blank of Comparative Example 1 having a structure in which a phase shift film, a light shielding film, and a hard mask film were laminated on a transparent substrate was manufactured.

[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. Further, similarly to Example 1, the phase shift pattern of the manufactured halftone type phase shift mask of Comparative Example 1 was subjected to intermittent irradiation with ArF excimer laser light at an integrated irradiation amount of 40 kJ/cm ² . The maximum CD change amount of the phase shift pattern 2a before and after this irradiation process was 3.5 nm, which did not reach the CD change amount that can ensure high transfer accuracy as a phase shift mask.

Further, using the mask blank of Comparative Example 1, a halftone phase shift mask of Comparative Example 1 is manufactured separately in the same procedure as in Example 1, and the phase shift mask is subjected to cleaning treatment with a chemical solution. It was The phase shift pattern of the phase shift mask after this cleaning treatment was observed with a cross-section TEM (Transmission Electron Microscope). As a result, the sidewall shape of the phase shift pattern had a step between the silicon nitride layer and the silicon oxide layer.

Next, with respect to the phase shift mask of Comparative Example 1 after the integrated irradiation treatment with ArF excimer laser light, AIMS193 (manufactured by Carl Zeiss) was used to perform exposure transfer to a resist film on a semiconductor device with exposure light having a wavelength of 193 nm. The transfer image at that time was simulated. When the exposure and transfer image of this simulation was verified, the design specifications could not be satisfied in the fine pattern portion. From this result, when the phase shift mask of Comparative Example 1 after the integrated irradiation treatment with ArF excimer laser light is set on the mask stage of the exposure apparatus and exposed and transferred to the resist film on the semiconductor device, it finally appears on the semiconductor device. It can be said that it is difficult to form a circuit pattern with high accuracy.

DESCRIPTION OF SYMBOLS 1 Translucent substrate 2 Phase shift film 2a 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 Second resist pattern 100 Mask blank 200 Phase shift mask

Claims (15)

A mask blank having a phase shift film on a transparent substrate,
The phase shift film is a single layer film having a composition gradient portion with an increased oxygen content in the surface on the side opposite to the translucent substrate and in the vicinity thereof,
The phase shift film is formed of a material consisting of one or more elements selected from non-metal elements and semi-metal elements, nitrogen and silicon,
X-ray photoelectron spectroscopy analysis is performed on the phase shift film to obtain a maximum peak PSi_f of photoelectron intensity of Si2p narrow spectrum in the phase shift film, and X-ray photoelectron spectroscopy analysis is performed on the transparent substrate. A number (PSi_f)/(PSi_s) obtained by dividing the maximum peak PSi_f of the phase shift film by the maximum peak PSi_s of the transparent substrate when the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is acquired. Is 1.09 or less. The mask blank according to claim 1, wherein the region of the phase shift film excluding the compositionally graded portion has a nitrogen content of 50 atomic% or more. 3. The mask blank according to claim 1, wherein the region of the phase shift film excluding the composition gradient portion has a silicon content of 35 atomic% or more. The mask blank according to claim 1, wherein the region of the phase shift film excluding the composition gradient portion has an oxygen content of 10 atomic% or less. The maximum peak of photoelectron intensity in the Si2p narrow spectrum is a maximum peak in a range of binding energy of 96 [eV] or more and 106 [eV] or less. Mask blank. The mask blank according to any one of claims 1 to 5, wherein the X-rays irradiated to the phase shift film in the X-ray photoelectron spectroscopy analysis are AlKα rays. The number of Si ₃ N ₄ bonds existing in the region of the phase shift film excluding the compositionally graded portion is determined as Si ₃ N ₄ bonds, Si _a N _b bonds (where b/[a+b]<4/7), Si-Si. The mask blank according to any one of claims 1 to 6, wherein a ratio divided by the total number of bonds, Si-O bonds, and Si-ON bonds is 0.88 or more. A phase shift mask comprising a phase shift film having a transfer pattern formed on a transparent substrate,
The phase shift film is a single layer film having a composition gradient portion with an increased oxygen content in the surface on the side opposite to the translucent substrate and in the vicinity thereof,
The phase shift film is formed of a material consisting of one or more elements selected from non-metal elements and semi-metal elements, nitrogen and silicon,
X-ray photoelectron spectroscopy analysis is performed on the phase shift film to obtain a maximum peak PSi_f of photoelectron intensity of Si2p narrow spectrum in the phase shift film, and X-ray photoelectron spectroscopy analysis is performed on the transparent substrate. A number (PSi_f)/(PSi_s) obtained by dividing the maximum peak PSi_f of the phase shift film by the maximum peak PSi_s of the transparent substrate when the maximum peak PSi_s of the photoelectron intensity of the Si2p narrow spectrum in the transparent substrate is acquired. Is 1.09 or less. 9. The phase shift mask according to claim 8, wherein the region of the phase shift film excluding the composition gradient portion has a nitrogen content of 50 atomic% or more. The phase shift mask according to claim 8 or 9, wherein a silicon content is 35 atom% or more in a region of the phase shift film excluding the composition gradient portion. 11. The phase shift mask according to claim 8, wherein the region of the phase shift film excluding the compositionally graded portion has an oxygen content of 10 atomic% or less. 12. The maximum peak of photoelectron intensity in the Si2p narrow spectrum is the maximum peak in the range of binding energy of 96 [eV] or more and 106 [eV] or less, according to any one of claims 8 to 11. Phase shift mask. The phase shift mask according to any one of claims 8 to 12, wherein the X-rays irradiated to the phase shift film in the X-ray photoelectron spectroscopy analysis are AlKα rays. The number of Si ₃ N ₄ bonds existing in the region of the phase shift film excluding the compositionally graded portion is determined as Si ₃ N ₄ bond, Si _a N _b bond (where b/[a+b]<4/7), Si-Si. The phase shift mask according to any one of claims 8 to 13, wherein the ratio divided by the total number of existing bonds, Si-O bonds, and Si-ON bonds is 0.88 or more. A method of manufacturing a semiconductor device, comprising the step of exposing and transferring a transfer pattern onto a resist film on a semiconductor substrate using the phase shift mask according to claim 8.

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