JP6830985B2 - Mask blank and transfer mask - Google Patents

Description

The present invention relates to a mask blank, a transfer mask, and a method for producing the mask blank.

Generally, a mask blank, which is an original plate of a transfer mask used in photolithography, is produced by forming a thin film for pattern formation on a translucent substrate such as synthetic quartz glass by a sputtering method. Ideally, the thin film of the mask blank does not have black defects or white defects, but practically, a certain number of defects are allowed in consideration of yield and the like. When a transfer mask is produced from a mask blank having defects in the thin film, the arrangement of patterns on a plane is adjusted so that each defect does not affect the exposure transfer. Therefore, for example, a defect inspection device as disclosed in Patent Document 1 is used to inspect the thin film of the mask blank for defects, and all the defects detected in the thin film are classified and their position coordinates. Is recorded in association with the mask blank.
On the other hand, in the case of a mask blank used for manufacturing a halftone type phase shift mask, as disclosed in Patent Document 2, a structure in which a halftone phase shift film and a light shielding film are sequentially laminated on a translucent substrate. In many cases.

Patent No. 3210654 JP-A-2005-284216

When manufacturing a mask blank as disclosed in Patent Document 2, a phase shift film is first formed on a translucent substrate by applying a sputtering method, and then a defect inspection is performed on the phase shift film. , A light-shielding film is formed on the phase-shift film by applying a sputtering method, and a defect inspection is performed on the light-shielding film. Generally, when a light-shielding film is formed on a defect existing in the phase-shift film, the shape of the defect of the phase-shift film is reflected on the surface of the light-shielding film even if the light-shielding film itself has no defect. It has been known.

Further, the size of the defect detected in the defect inspection of the phase shift film and the size of the defect detected at the same position as the defect of the phase shift film in the defect inspection of the light shielding film after the light shielding film is formed are not necessarily the same. It does not become. If the size of the defect detected by the light-shielding film defect inspection tends to be larger than the defect size detected by the phase-shift film defect inspection at the same position as the defect, the phase-shift film defect inspection tends to be larger. This is a preferable mask blank configuration because it increases the possibility that defects that could not be detected can be found by defect inspection of the light-shielding film.

However, depending on the combination of the phase shift film and the light-shielding film, the structure opposite to the preferable mask blank structure, that is, the light-shielding film is located at the same position as the defect rather than the defect size detected by the defect inspection of the phase-shift film. In some cases, the size of the defect detected by the defect inspection may be smaller, which has been a problem.

Therefore, an object of the present invention is to provide a mask blank, a transfer mask, and a method for manufacturing a mask blank, which can make it easier to detect a defect in a defect inspection.

In order to achieve the above object, the present invention has the following configuration.
(Structure 1)
A mask blank having a structure in which a first film and a second film are laminated in this order on a translucent substrate.
The first film and the second film are both formed of a material containing one or more elements of metal and silicon.
From the surface reflectance of the second film to light of a predetermined wavelength in the state where the second film is laminated on the first film, in the state where no other film is laminated on the first film. A mask blank characterized in that the difference calculated by subtracting the surface reflectance of the first film with respect to light having a predetermined wavelength is 10% or less.

(Structure 2)
The mask blank according to configuration 1, wherein the predetermined wavelength is 488 nm to 532 nm.
(Structure 3)
2. The structure 1 or 2 is characterized in that the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film is 20% or more. Mask blank.

(Structure 4)
The surface reflectance of the first film with respect to light of a predetermined wavelength in a state where no other film is laminated on the first film, and the state in which the second film is laminated on the first film. The mask blank according to any one of configurations 1 to 3, wherein the surface reflectance of the second film with respect to light having a predetermined wavelength is 35% or less.

(Structure 5)
The mask blank according to any one of configurations 1 to 4, wherein the first film is a light transmissive film having a transmittance of 1% or more with respect to exposure light.
(Structure 6)
The light semi-transmissive film has a function of causing a predetermined phase difference between the exposure light transmitted through the light semi-transmissive film and the exposure light passing through the air at the same distance as the thickness of the light semi-transmissive film. 5. The mask blank according to the configuration 5, wherein the mask blank has.

(Structure 7)
The mask according to the configuration 5 or 6, wherein the second film is a light-shielding film, and the optical density with respect to the exposure light in the laminated structure of the light semi-transmissive film and the light-shielding film is 2.5 or more. blank.
(Structure 8)
The mask blank according to any one of configurations 5 to 7, wherein the exposure light is ArF excimer laser light.

(Structure 9)
The mask blank according to any one of configurations 1 to 8, wherein the light having a predetermined wavelength is an inspection light used in a defect inspection of the mask blank.
(Structure 10)
The mask blank according to any one of configurations 1 to 9, wherein the first film is made of a material containing silicon and nitrogen.

(Structure 11)
The mask according to any one of configurations 1 to 10, wherein the second film is made of a material containing chromium and further containing one or more elements selected from oxygen, nitrogen and carbon. blank.
(Structure 12)
A transfer mask characterized in that a first pattern is formed on the first film and a second pattern is formed on the second film in the mask blank according to any one of configurations 1 to 11. ..

(Structure 13)
A method for manufacturing a mask blank having a structure in which a first film and a second film are laminated in this order on a translucent substrate.
A process of forming a first film on a translucent substrate by a sputtering method,
A first defect inspection step of irradiating the first film formed on the translucent substrate with inspection light to inspect the defects, and
A step of forming a second film on the first film by a sputtering method and
It has a second defect inspection step of irradiating the second film formed on the first film with inspection light to perform a defect inspection.
The first film and the second film have the first film based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. It is characterized in that the difference calculated by subtracting the surface reflectance of the first film with respect to light of a predetermined wavelength in a state where no other film is laminated on the film is 10% or less. Manufacturing method of mask blank.

(Structure 14)
The method for producing a mask blank according to the configuration 13, wherein the predetermined wavelength is 488 nm to 532 nm.
(Structure 15)
13. The configuration 13 or 14, wherein the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film is 20% or more. Manufacturing method of mask blank.

(Structure 16)
The first film and the second film have the surface reflectance of the first film with respect to light of a predetermined wavelength in a state where no other film is laminated on the first film, and the first film. Any of the configurations 13 to 15, characterized in that the second film is formed under the condition that the surface reflectance of the second film with respect to light of a predetermined wavelength is 35% or less in a state where the second film is laminated on the top. The method for manufacturing a mask blank described in Crab.
(Structure 17)
The method for producing a mask blank according to any one of configurations 13 to 16, wherein the light having the predetermined wavelength is the inspection light.

According to the present invention, it is possible to provide a mask blank, a transfer mask, and a method for producing a mask blank, which can make it easier to detect defects in a defect inspection.

It is sectional drawing which shows an example of a mask blank. The reflectance spectra of the first film and the second film of the mask blank produced in Example 1 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 1. The reflectance spectra of the first film and the second film of the mask blank produced in Example 2 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 2. The reflectance spectra of the first film and the second film of the mask blank produced in Example 3 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 3. The reflectance spectra of the first film and the second film of the mask blank prepared in Example 4 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 4. The reflectance spectra of the first film and the second film of the mask blank prepared in Example 5 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 5. The reflectance spectra of the first film and the second film of the mask blank prepared in Example 6 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 6. The reflectance spectra of the first film and the second film of the mask blank prepared in Example 7 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Example 7. The reflectance spectra of the first film and the second film of the mask blank produced in Comparative Example 1 are shown. It is a graph which shows the result of having compared the defect size of the 1st film and the defect size of the 2nd film of the mask blank produced in Comparative Example 1.

The present inventor conducted a defect inspection on a mask blank of a combination of various phase shift films and a light-shielding film, and conducted a diligent study. As a result, the present inventor, when the reflectance of the film with respect to light of a predetermined wavelength (for example, inspection light) satisfies the following conditions, is larger than the size of the defect detected in the defect inspection of the phase shift film. It was found that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger at the same position as the defect.

Specifically, from the surface reflectance of the light-shielding film when the light-shielding film is laminated on the phase-shift film, the phase-shift film in the state where the light-shielding film is not laminated (the surface of the phase-shift film is exposed) When the difference calculated by subtracting the surface reflectance is 10% or less, the size of the defect detected by the defect inspection of the light-shielding film at the same position as the defect is larger than the defect size detected by the defect inspection of the phase shift film. I found that there is a tendency for it to be larger.

Further, when the surface reflectance of the light-shielding film in a state where the light-shielding film is laminated on the phase-shift film is 20% or more, the defect size detected by the defect inspection of the phase-shift film is at the same position as the defect. It was found that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger.

Further, the surface reflectance of the phase shift film in the state where no other film is laminated on the phase shift film and the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film are both 35. When it is less than%, it is found that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger than the defect size detected by the defect inspection of the phase shift film at the same position as the defect. It was.

In general, the surface reflectance of the light-shielding film in a state where the light-shielding film is laminated on the phase-shift film is other than the light-shielding film laminated on the translucent substrate without passing through another film, or a phase-shift film. It is different from the surface reflectance of the light-shielding film laminated on the other film. Therefore, even when the surface reflectance of these light-shielding films is described in publicly known documents and the like, it cannot be a motivation for those skilled in the art to come up with the present invention.

Further, the tendency of the defect size as described above is not limited to the mask blank having a laminated structure of the phase shift film and the light-shielding film, and similarly in the mask blank having a laminated structure of a combination of two or more other films. Found. For example, in a mask blank having a structure in which a first film and a second film are laminated in this order on a translucent substrate, a second film in a state where the second film is laminated on the first film The difference calculated by subtracting the surface reflectance of the first film for the light of the predetermined wavelength in the state where no other film is laminated on the first film is 10% or less from the surface reflectance for the light of the predetermined wavelength. In some cases, the size of the defect detected by the second film defect inspection at the same position as the defect tends to be larger than the size of the defect detected by the defect inspection of the first film. Found.

Furthermore, it was found that the same tendency was found when another film was interposed between the translucent substrate and the first film. For example, in a mask blank having a structure in which a third film, a first film, and a second film are laminated in this order on a translucent substrate, a state in which the second film is laminated on the first film. Difference calculated by subtracting the surface reflectance of the first film for light of a predetermined wavelength from the surface reflectance of the second film for light of a predetermined wavelength in a state where no other film is laminated on the first film. Is 10% or less, the size of the defect detected by the defect inspection of the second film at the same position as the defect is larger than the size of the defect detected by the defect inspection of the first film. It was found that there was a tendency.

Hereinafter, the mask blank, the transfer mask, and the method for manufacturing the mask blank according to the embodiment of the present invention will be described in detail.

(Mask blank)
FIG. 1 is a cross-sectional view showing an example of a mask blank. As shown in FIG. 1, the mask blank 10 of the present embodiment has a structure in which the first film 12 and the second film 14 are laminated in this order on the translucent substrate 20. The first film 12 and the second film 14 are both made of a material containing one or more elements of metal and silicon.

From the surface reflectance of the second film 14 with respect to light of a predetermined wavelength in the state where the second film 14 is laminated on the first film 12, another film is not laminated on the first film 12 ( The difference calculated by subtracting the surface reflectance of the first film 12 with respect to the light of a predetermined wavelength in the state where the first film 12 is exposed is preferably 10% or less, preferably -10% or more + 10% or less (in a state where the first film 12 is exposed). It is more preferable that the absolute value is 10% or less).

The mask blank of the present embodiment can be preferably applied, for example, in the case of the following configuration.
(1) In the case of a mask blank provided with a light semi-transmissive film The light semi-transmissive film is provided with an exposure light in addition to a halftone phase shift film that transmits exposure light at a predetermined transmittance and causes a predetermined phase difference. Some films are mainly used in enhancer-type masks, which have optical characteristics that allow transmitted light to pass through at a predetermined transmittance but do not cause a phase difference in the transmitted light. In the case of a mask blank provided with any of the light transflective films, a light-shielding film for forming a light-shielding band is often required. For this reason, it is often the case that the light transmissive film and the light-shielding film are laminated in this order on the translucent substrate. The optical semi-transmissive film is the first film 12, the light-shielding film is the second film 14, and the relationship between the first film and the second film of the present invention shown above is satisfied, and each film has It is advisable to select the materials for forming the light transmissive film and the light-shielding film so as to satisfy the originally required functions (optical characteristics, etching characteristics, etc.).

In the case where the hard mask film is laminated on the light-shielding film, the light-shielding film is the first film 12, the hard mask film is the second film 14, and the first film of the present invention shown above is used. The materials of the light-shielding film and the hard mask film may be selected so as to satisfy the relationship with the second film and to satisfy the functions (optical characteristics, etching characteristics, etc.) originally required for each film.

In the case of a configuration in which an etching stopper film is provided between the translucent substrate and the light semitransmissive film, the etching stopper film (first film 12) and the light semitransmissive film (second film 14) are shown above. Etching stopper film and translucent light so as to satisfy the relationship between the first film and the second film of the present invention and to satisfy the functions (optical characteristics, etching characteristics, etc.) originally required for each film. It is advisable to select each film material.

In the case of a configuration in which an etching stopper film is provided between the light semi-transmissive film and the light-shielding film, the light semi-transmissive film (first film 12) and the etching stopper film (second film 14) are shown in the above-mentioned book. The light semi-transmissive film and the etching stopper film so as to satisfy the relationship between the first film and the second film of the present invention and to satisfy the functions (optical characteristics, etching characteristics, etc.) originally required for each film. It is advisable to select each material. Further, the etching stopper film (first film 12) and the light-shielding film (second film 14) satisfy the relationship between the first film and the second film of the present invention shown above, and each of them. It is advisable to select the materials for the etching stopper film and the light-shielding film so that the film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

Examples of the material for forming the light semi-transmissive film include a material containing silicon without containing a transition metal and a material containing a transition metal and silicon (hereinafter, these are collectively referred to as a silicon-based material). Be done. Examples of the transition metal contained in these materials include one or more elements selected from molybdenum, tungsten, titanium, tantalum, zirconium, hafnium, niobium, vanadium, cobalt, chromium and nickel. Since the light semi-transmissive film is required to transmit the exposure light at a predetermined transmittance, it preferably contains one or more elements selected from oxygen and nitrogen.

In the case of a mask blank structure in which a light-shielding film is provided in contact with the light-transmissive film, the material forming the light-shielding film is sufficiently selected for etching with respect to the etching gas used when patterning the light-transmissive film. It is required to apply a material having properties. When the light semi-transmissive film is formed of a silicon-based material, the light-shielding film is preferably a material having high resistance to dry etching with a fluorine-based gas. In this case, the light-shielding film is preferably formed of a material containing chromium (hereinafter referred to as a chromium-based material). The chromium-based material is preferably a simple substance of chromium or a material containing one or more elements selected from oxygen, nitrogen, carbon, hydrogen, fluorine and boron in chromium. Further, a material containing one or more elements selected from hafnium and zirconium in tantalum (hereinafter referred to as TaHf-based material) is also preferable. When the hard mask film is provided on the light-shielding film formed of a chromium-based material or a TaHf-based material, the hard mask film is preferably formed of a silicon-based material.

On the other hand, in the case of a configuration in which an etching stopper film is provided between the light semitransmissive film and the light shielding film, the etching stopper film is preferably formed of a chromium-based material or a TaHf-based material. In this case, the light-shielding film is preferably formed of a silicon-based material, and may be formed of a tantalum-containing material (hereinafter, referred to as a tantalum-based material). The tantalum-based material is preferably a material in which tantalum contains one or more elements selected from nitrogen, oxygen, carbon, hydrogen and boron. Further, in the case where the light-shielding film is formed of a silicon-based material and the hard mask film is provided on the light-shielding film, the hard mask film is preferably formed of a chromium-based material or a TaHf-based material.

On the other hand, in the case of a configuration in which an etching stopper film is provided between the translucent substrate and the light semitransmissive film, the etching stopper film has etching selectivity between both the translucent substrate and the light semitransmissive film. Is required. In this case, the etching stopper film is preferably formed of a chromium-based material or a TaHf-based material.

(2) In the case of a binary mask blank The binary mask blank often has a structure in which a light-shielding film and a hard mask film are laminated in this order on a translucent substrate. The light-shielding film (first film 12) and the hard mask film (second film 14) satisfy the relationship between the first film and the second film of the present invention shown above, and each film satisfies the relationship. It is advisable to select the materials for the light-shielding film and the hard mask film so as to satisfy the originally required functions (optical characteristics, etching characteristics, etc.). In particular, when a binary mask blank suitable for a substrate digging Levenson type phase shift mask is used, an etching stopper film may be provided between the translucent substrate and the light-shielding film. In this case, the etching stopper film (first film 12) and the light-shielding film (second film 14) satisfy the relationship between the first film and the second film of the present invention shown above, and It is advisable to select the materials of the etching stopper film and the light-shielding film so that each film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

As the material for forming the light-shielding film of the binary mask blank, a material containing a transition metal and silicon (hereinafter referred to as a transition metal silicide-based material) and a tantalum-based material are preferably used in addition to a chromium-based material. When a light-shielding film is formed of a chromium-based material and a hard mask film is provided on the light-shielding film, a silicon-based material, a tantalum-based material, or a TaHf-based material can be applied to the hard mask film. In the case where a light-shielding film is formed of a transition metal silicide-based material and a hard mask film is provided on the light-shielding film, a chromium-based material, a tantalum-based material, or a TaHf-based material can be applied to the hard mask film. When a light-shielding film is formed of a tantalum-based material and a hard mask film is provided on the light-shielding film, a chromium-based material can be applied to the hard mask film.

(3) In the case of a reflective mask blank The reflective mask blank has a structure in which a multilayer reflective film that reflects exposure light, a protective film that protects the multilayer reflective film, and an absorber film that forms a transfer pattern are laminated in this order on a substrate. It is equipped with. Further, there is also a configuration in which a hard mask film is provided on the absorber film and a configuration in which a buffer film is provided between the protective film and the absorber film. For example, the protective film (first film 12) and the absorber film (second film 14) satisfy the relationship between the first film and the second film of the present invention shown above, and each of them. The effect of the present invention can be obtained by selecting the materials of the protective film and the absorber film so that the film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

The buffer membrane (first membrane 12) and the absorber membrane (second membrane 14) satisfy the relationship between the first membrane and the second membrane of the present invention shown above, and each membrane satisfies the relationship. It is advisable to select the materials of the buffer film and the absorber film, respectively, so as to satisfy the originally required functions (optical characteristics, etching characteristics, etc.).
Further, the absorber film (first film 12) and the hard mask film (second film 14) satisfy the relationship between the first film and the second film of the present invention shown above, and It is advisable to select the materials of the absorber film and the hard mask film so that each film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

In the case of a reflective mask blank to which EUV (Extreme Ultra Violet) light is applied to the exposure light, a material containing ruthenium is preferable for the protective film, and a tantalum-based material or a TaHf-based material is particularly preferable for the absorber film. Used. In the case of a configuration in which an absorber film is formed of a tantalum-based material and a hard mask film is provided on the absorber film, a chromium-based material can be applied to the hard mask film.
In the case where the absorber film is formed of a tantalum-based material and a buffer film is provided between the protective film and the absorber film, a chromium-based material can be applied to the buffer film.

The predetermined wavelength is preferably 488 nm to 532 nm.
The light having the predetermined wavelength is preferably the inspection light used in the mask blank defect inspection apparatus.

The surface reflectance of the second film 14 with respect to light of a predetermined wavelength in a state where the second film 14 is laminated on the first film 12 is preferably 20% or more.

The first film 12 is preferably a translucent film having a transmittance of 1% or more with respect to the exposure light.
The light semi-transmissive film has a function of causing a predetermined phase difference between the exposure light transmitted through the light semi-transmissive film and the exposure light passing through the air at the same distance as the thickness of the light semi-transmissive film. It is preferable to have.
That is, the first film 12 is preferably a halftone phase shift film.

The first film 12 is preferably formed of a material containing silicon (Si) and nitrogen (N). Examples of such materials include MoSiN and the like.

The second film 14 is preferably a light-shielding film.
The second film 14 is preferably formed of a material containing chromium (Cr) and further containing one or more elements selected from oxygen (O), nitrogen (N) and carbon (C). Examples of such materials include CrO, CrN, CrON, CrOCN, CrBON, CrBOCN and the like.

The optical density with respect to the exposure light in the laminated structure of the light semi-transmissive film and the light-shielding film is required to be 2.5 or more, and preferably 2.8 or more. In the case of a transfer mask manufactured using such a mask blank, when the pattern is exposed and transferred to a resist film on a semiconductor wafer using an exposure apparatus, the region where the transfer pattern of the transfer mask is formed. This is because it is possible to suppress the influence of the resist film on the semiconductor wafer by the exposure light transmitted through the outer peripheral region other than the above.

In the mask blank 10 of the present embodiment, each of the first film and the second film has a single-layer structure, a laminated structure of two or more layers, and a film structure whose composition is inclined in the thickness direction of the film. You may have.

In the mask blank 10 of the present embodiment, examples of the material of the translucent substrate 20 include synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO _2- TiO ₂ glass, etc.). And so on. 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 mask blank substrate (translucent substrate).

As the exposure light applied to the mask blank and the transfer mask of the present invention, ArF excimer laser light, KrF excimer laser light, i-ray light and the like can be used, and there is no particular limitation, but ArF excimer laser light Is preferably used.

(Transfer mask)
A transfer mask can be manufactured by forming a first pattern on the first film 12 of the mask blank 10 described above and forming a second pattern on the second film 14. A known pattern forming method can be used for forming the first pattern on the first film 12 and forming the second pattern on the second film 14.

For example, a resist film having a first pattern is formed on the surface of the second film 14, and a first pattern is formed on the second film 14 by dry etching using a mixed gas of a chlorine-based gas and an oxygen gas. To do. Next, after peeling off the resist film having the first pattern, the first pattern is formed on the first film 12 by dry etching using a fluorine-based gas using the second film 14 having the first pattern as a mask. To form. Next, a resist film having a second pattern is formed on the surface of the second film 14, and a second pattern is formed on the second film 14 by dry etching using a mixed gas of a chlorine-based gas and an oxygen gas. Form. As a result, the first pattern can be formed on the first film 12, and the second pattern can be formed on the second film 14.

The transfer mask of the present invention is produced by using the mask blank of the present invention. Therefore, the characteristics of the translucent substrate, the first film, and the second film in the transfer mask of the present invention are the translucent substrate 20 and the first film 12 in the mask blank 10 described above. , And the same as the second film 14.

(Manufacturing method of mask blank)
The mask blank manufacturing method of the present embodiment includes the following steps.
(1) A step of forming a first film 12 on a translucent substrate 20 by a sputtering method.
(2) A first defect inspection step of irradiating the first film 12 formed on the translucent substrate 20 with inspection light to inspect the defects.
(3) A step of forming a second film 14 on the first film 12 by a sputtering method.
(4) A second defect inspection step of irradiating the second film 14 formed on the first film 12 with inspection light to inspect the defects.

In the method for producing a mask blank of the present embodiment, the first film 12 and the second film 14 have a predetermined wavelength of the second film 14 in a state where the second film 14 is laminated on the first film 12. The difference calculated by subtracting the surface reflectance of the first film 12 for light of a predetermined wavelength in a state where no other film is laminated on the first film 12 is 10% or less. It is formed under the conditions that

The surface reflectance of the second film 14 with respect to light of a predetermined wavelength in a state where the second film 14 is laminated on the first film 12 is preferably 20% or more.

The first film 12 and the second film 14 have the surface reflectance of the first film 12 with respect to light of a predetermined wavelength in a state where no other film is laminated on the first film 12, and the first film. It is preferable that the surface reflectance of the second film 14 with respect to light of a predetermined wavelength in a state where the second film 14 is laminated on the 12 is 35% or less.

The light having the predetermined wavelength is preferably the inspection light of the defect inspection apparatus used in the first defect inspection step or the second defect inspection step.
The predetermined wavelength is preferably 488 nm to 532 nm.

A known mask blank defect inspection device can be used for defect inspection of the first film 12 and the second film 14. For example, the defect inspection apparatus disclosed in Japanese Patent No. 3210654 can be used.

Hereinafter, the present invention will be described in more detail with reference to Examples.
(Example 1)
In Example 1, first, a mixed target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) is used on a translucent substrate made of synthetic quartz glass by using a single-wafer sputtering apparatus. : 89) was used to form a first film (halftone phase shift film) made of MoSiN with a film thickness of 69 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. Using a phase shift amount measuring device (MPM193 manufactured by Lasertech), the transmittance and the phase shift amount for light having a wavelength of 193 nm, which is the wavelength of ArF exposure light of this halftone phase shift film, were measured, and the transmittance was 6.16. %, The phase shift amount was 178.1 degrees.

After forming the first film on the translucent substrate, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). The wavelength of the inspection light used in this defect inspection apparatus is 488 nm. Next, the surface reflectance of the first film with respect to light having a wavelength of 200 nm to 800 nm was measured using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100).

Next, a second film (light-shielding film) composed of three layers, a lower layer, an intermediate layer, and an upper layer, was formed on the first film. Specifically, in a single-wafer sputtering apparatus, a CrOCN film (lower layer) is formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, carbon dioxide, nitrogen, and helium using a chromium (Cr) target. A film was formed with a thickness of 30 nm. Next, on the lower layer, a CrN film (intermediate layer) is filmed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon and nitrogen using a chromium (Cr) target with a single-wafer sputtering device. A film was formed at 4 nm. Next, on the intermediate layer, a CrOCN film (CrOCN film) was subjected to reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, carbon dioxide, nitrogen and helium using a chromium (Cr) target in a single-wafer sputtering apparatus. The upper layer) was formed with a film thickness of 14 nm. The optical density of the laminated structure of the halftone phase shift film and the light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer, the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 1 below shows the structure, film material, optical characteristics, and film forming conditions of the mask blank of Example 1 produced above. For each optical characteristic (refractive index n and extinction coefficient k) of the first film and the second film with respect to light having a wavelength of 488 nm and a wavelength of 532 nm, an optical thin film characteristic measuring device (n & k Technology, n & k1280) is used. Calculated using. However, a film in which only the first film is formed on the translucent substrate and a film in which only the second film is formed on the translucent substrate are separately prepared, and these are used to prepare the first film and the second film. Each optical characteristic of is calculated. The calculation of this optical characteristic is the same in each of the following Examples and Comparative Examples.

FIG. 2 shows a reflectance spectrum in a state in which no other film is laminated on the first film of the mask blank produced in Example 1, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 2, in the mask blank produced in Example 1, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 28.4%, which is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 26.3%, and the difference was 2.1%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 29.7% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 28.4%, and the difference was 1.3%.

FIG. 3 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 1. The graph of FIG. 3 is not the data of the defect size of one mask blank, but the data of the defect size of a plurality of mask blanks. In FIG. 3, the horizontal axis represents the size of the defect detected in the first film. The vertical axis shows the size of the defect detected in the second film. The square dots indicate pinholes (concave defects). The round dots indicate particles (convex defects). Each point indicates the size of the defect detected in the first film and the size of the defect detected in the second film at the same position (coordinates) as the defect. Assuming that the horizontal axis is the X axis and the vertical axis is the Y axis, the point located above the Y = X straight line is the second film rather than the size of the defect detected in the first film. It shows that the size of the defect detected in is large. On the contrary, the point located below the Y = X straight line indicates that the size of the defect detected in the second film is smaller than the size of the defect detected in the first film. In the following examples, the view of the defect size graph (scatter plot) is the same.

From FIGS. 2 and 3, from the surface reflectance of the light-shielding film in the state where the light-shielding film is laminated on the phase-shift film, the phase shift in the state where the light-shielding film is not laminated (the surface of the phase-shift film is exposed). When the difference calculated by subtracting the surface reflectance of the film is 10% or less, the defect detected by the defect inspection of the light-shielding film at the same position as the defect is larger than the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the above tends to be larger.

Further, when the surface reflectance of the light-shielding film in the state where the light-shielding film is laminated on the phase-shift film is 20% or more, the defect size detected by the defect inspection of the phase-shift film is at the same position as the defect. It can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger.

Further, the surface reflectance of the phase shift film in the state where no other film is laminated on the phase shift film and the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film are both 35. When it is less than%, it can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger than the defect size detected by the defect inspection of the phase shift film at the same position as the defect. ..

(Example 2)
In Example 2, first, a mixed target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) was used on a translucent substrate made of synthetic quartz glass using a single-wafer sputtering apparatus. : 89) was used to form a first film (halftone phase shift film) made of MoSiN with a film thickness of 69 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. Using a phase shift amount measuring device (MPM193 manufactured by Lasertech), the transmittance and the phase shift amount for light having a wavelength of 193 nm, which is the wavelength of ArF exposure light of this halftone phase shift film, were measured, and the transmittance was 6.16. %, The phase shift amount was 178.1 degrees.

After forming the first film on the translucent substrate, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). In addition, the surface reflectance of the first film with respect to light having a wavelength of 200 nm to 800 nm was measured using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100).

Next, a second film (light-shielding film) composed of three layers, a lower layer, an intermediate layer, and an upper layer, was formed on the first film. Specifically, a CrN film (lower layer), a CrC film (intermediate layer), and a CrON film (upper layer) were continuously formed by reactive sputtering (DC sputtering) using a chrome (Cr) target by an in-line sputtering device. .. The film thickness of the lower layer and the intermediate layer was formed to be 26 nm, and the film thickness of the upper layer was formed to be 22 nm. The optical density of the laminated structure of the halftone phase shift film and the light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 2 below shows the structure, film material, optical characteristics, and film forming conditions of the mask blank of Example 2 produced above.

FIG. 4 shows a reflectance spectrum in a state in which no other film is laminated on the first film of the mask blank produced in Example 2, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 4, in the mask blank produced in Example 2, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 24.7%, which is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 26.3%, and the difference was -1.6%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 27.6% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 28.4%, and the difference was −0.8%.

FIG. 5 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 2.

From FIGS. 4 and 5, from the surface reflectance of the light-shielding film in the state where the light-shielding film is laminated on the phase-shift film, the phase shift in the state where the light-shielding film is not laminated (the surface of the phase-shift film is exposed). When the difference calculated by subtracting the surface reflectance of the film is 10% or less, the defect detected by the defect inspection of the light-shielding film at the same position as the defect is larger than the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the above tends to be larger.

Further, when the surface reflectance of the light-shielding film in the state where the light-shielding film is laminated on the phase-shift film is 20% or more, the defect size detected by the defect inspection of the phase-shift film is at the same position as the defect. It can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger.

Further, the surface reflectance of the phase shift film in the state where no other film is laminated on the phase shift film and the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film are both 35. When it is less than%, it can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger than the defect size detected by the defect inspection of the phase shift film at the same position as the defect. ..

(Example 3)
In Example 3, first, a mixing target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) is used on a translucent substrate made of synthetic quartz glass by using a single-wafer sputtering apparatus. : 89) was used to form a first film (halftone phase shift film) made of MoSiN with a film thickness of 69 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. Using a phase shift amount measuring device (MPM193 manufactured by Lasertech), the transmittance and the phase shift amount for light having a wavelength of 193 nm, which is the wavelength of ArF exposure light of this halftone phase shift film, were measured, and the transmittance was 6.16. %, The phase shift amount was 178.1 degrees.

After forming the first film on the translucent substrate, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). In addition, the surface reflectance of the first film with respect to light having a wavelength of 200 nm to 800 nm was measured using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100).

Next, a second film (light-shielding film) composed of two layers, a lower layer and an upper layer, was formed on the first film. Specifically, in a single-wafer sputtering apparatus, a CrOCN film (lower layer) is formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, carbon dioxide, nitrogen, and helium using a chromium (Cr) target. A film was formed with a thickness of 47 nm. Next, on the lower layer, a CrN film (upper layer) with a film thickness of 5 nm was formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon and nitrogen using a chromium (Cr) target with a single-wafer sputtering apparatus. The film was formed in. The optical density of the laminated structure of the halftone phase shift film and the light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 3 below shows the structure, film material, optical characteristics, and film forming conditions of the mask blank of Example 3 produced above.

FIG. 6 shows the reflectance spectrum in the state where the other film is not laminated on the first film of the mask blank produced in Example 3, and the state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 6, in the mask blank produced in Example 3, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 32.6%, and is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 26.3%, and the difference was 6.3%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 29.6% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 28.4%, and the difference was 1.2%.

FIG. 7 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 3.

From FIGS. 6 and 7, from the surface reflectance of the light-shielding film in the state where the light-shielding film is laminated on the phase-shift film, the phase shift in the state where the light-shielding film is not laminated (the surface of the phase-shift film is exposed). When the difference calculated by subtracting the surface reflectance of the film is 10% or less, the defect detected by the defect inspection of the light-shielding film at the same position as the defect is larger than the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the above tends to be larger.

Further, when the surface reflectance of the light-shielding film in the state where the light-shielding film is laminated on the phase-shift film is 20% or more, the defect size detected by the defect inspection of the phase-shift film is at the same position as the defect. It can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger.

Further, the surface reflectance of the phase shift film in the state where no other film is laminated on the phase shift film and the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film are both 35. When it is less than%, it can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be larger than the defect size detected by the defect inspection of the phase shift film at the same position as the defect. ..

(Example 4)
In Example 4, first, a mixed target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) is used on a translucent substrate made of synthetic quartz glass by using a single-wafer sputtering apparatus. : 89) was used to form a third film (halftone phase shift film) made of MoSiN with a film thickness of 69 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. Using a phase shift amount measuring device (MPM193 manufactured by Lasertech), the transmittance and the phase shift amount for light having a wavelength of 193 nm, which is the wavelength of ArF exposure light of this halftone phase shift film, were measured, and the transmittance was 6.16. %, The phase shift amount was 178.1 degrees.

Next, a first film (light-shielding film) composed of three layers, a lower layer, an intermediate layer, and an upper layer, was formed on the third film. Specifically, in a single-wafer sputtering apparatus, a CrOCN film (lower layer) is formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, carbon dioxide, nitrogen, and helium using a chromium (Cr) target. A film was formed with a thickness of 30 nm. Next, on the lower layer, a CrN film (intermediate layer) is filmed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon and nitrogen using a chromium (Cr) target with a single-wafer sputtering device. A film was formed at 4 nm. Next, on the intermediate layer, a CrOCN film (CrOCN film) was subjected to reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, carbon dioxide, nitrogen and helium using a chromium (Cr) target in a single-wafer sputtering apparatus. The upper layer) was formed with a film thickness of 14 nm. The optical density of the laminated structure of the halftone phase shift film and the light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the first film on the third film, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the first film in a state of being laminated on the third film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Next, a second film (hardmask film) was formed on the first film. Specifically, in a single-wafer sputtering apparatus, a SiON film (second film) is formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, oxygen, and nitrogen using a silicon (Si) target. A film was formed with a thickness of 15 nm.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 4 below shows the structure, film material, optical properties, and film forming conditions of the mask blank of Example 4 produced above.

FIG. 8 shows a reflectance spectrum in a state in which no other film is laminated on the first film of the mask blank produced in Example 4, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 8, in the mask blank produced in Example 4, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 22.2%, which is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 28.4%, and the difference was -6.2%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 24.0% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 29.7%, and the difference was −5.7%.

FIG. 9 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 4.

From FIGS. 8 and 9, in a mask blank having a structure in which a first film (light-shielding film) and a second film (hard mask film) are laminated in this order on a translucent substrate, on the first film. From the surface reflectance of the second film to the light of the predetermined wavelength in the state where the second film is laminated, to the light of the predetermined wavelength of the first film in the state where the other film is not laminated on the first film. When the difference calculated by subtracting the surface reflectance is 10% or less, it was detected by the defect inspection of the second film at the same position as the defect than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect tends to be larger.

Further, when the surface reflectance of the second film is 20% or more in the state where the second film is laminated on the first film, the defect size is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect detected by the defect inspection of the second film tends to be larger at the same position as the defect.

Further, the surface reflectance of the first film in the state where the other film is not laminated on the first film, and the surface reflectance of the second film in the state where the second film is laminated on the first film. When the surface reflectances are all 35% or less, the size of the defect detected by the defect inspection of the second film at the same position as the defect is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size tends to be larger.

Further, such a tendency of defect size is the same even when a third film (halftone phase shift film) is interposed between the translucent substrate and the first film. I understand.

(Example 5)
In Example 5, first, a mixed target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) was used on a translucent substrate made of synthetic quartz glass using a single-wafer sputtering apparatus. : 89) was used to form a third film (halftone phase shift film) made of MoSiN with a film thickness of 69 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. Using a phase shift amount measuring device (MPM193 manufactured by Lasertech), the transmittance and the phase shift amount for light having a wavelength of 193 nm, which is the wavelength of ArF exposure light of this halftone phase shift film, were measured, and the transmittance was 6.16. %, The phase shift amount was 178.1 degrees.

Next, a first film (light-shielding film) composed of three layers, a lower layer, an intermediate layer, and an upper layer, was formed on the third film. Specifically, a CrN film (lower layer), a CrC film (intermediate layer), and a CrON film (upper layer) were continuously formed by reactive sputtering (DC sputtering) using a chrome (Cr) target by an in-line sputtering device. .. The film thickness of the lower layer and the intermediate layer was formed to be 26 nm, and the film thickness of the upper layer was formed to be 22 nm. The optical density of the laminated structure of the halftone phase shift film and the light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the first film on the third film, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the first film in a state of being laminated on the third film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Next, a second film (hardmask film) was formed on the first film. Specifically, in a single-wafer sputtering apparatus, a SiON film (second film) is formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, oxygen, and nitrogen using a silicon (Si) target. A film was formed with a thickness of 15 nm.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 5 below shows the structure, film material, optical properties, and film forming conditions of the mask blank of Example 5 produced above.

FIG. 10 shows the reflectance spectrum in a state where no other film is laminated on the first film of the mask blank produced in Example 5, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 10, in the mask blank produced in Example 5, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 16.9%, which is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 24.7%, and the difference was −7.8%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 20.6% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 27.6%, and the difference was −7.0%.

FIG. 11 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 5.

From FIGS. 10 and 11, in a mask blank having a structure in which a first film (light-shielding film) and a second film (hard mask film) are laminated in this order on a translucent substrate, on the first film. From the surface reflectance of the second film to the light of the predetermined wavelength in the state where the second film is laminated, to the light of the predetermined wavelength of the first film in the state where the other film is not laminated on the first film. When the difference calculated by subtracting the surface reflectance is 10% or less, it was detected by the defect inspection of the second film at the same position as the defect than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect tends to be larger.

Further, when the surface reflectance of the second film is 20% or more in the state where the second film is laminated on the first film, the defect size is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect detected by the defect inspection of the second film tends to be larger at the same position as the defect.

Further, the surface reflectance of the first film in the state where the other film is not laminated on the first film, and the surface reflectance of the second film in the state where the second film is laminated on the first film. When the surface reflectances are all 35% or less, the size of the defect detected by the defect inspection of the second film at the same position as the defect is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size tends to be larger.

Further, such a tendency of defect size is the same even when a third film (halftone phase shift film) is interposed between the translucent substrate and the first film. I understand.

(Example 6)
In Example 6, first, a mixing target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) is used on a translucent substrate made of synthetic quartz glass by using a single-wafer sputtering apparatus. : 89) was used to form a third film (halftone phase shift film) made of MoSiN with a film thickness of 69 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. Using a phase shift amount measuring device (MPM193 manufactured by Lasertech), the transmittance and the phase shift amount for light having a wavelength of 193 nm, which is the wavelength of ArF exposure light of this halftone phase shift film, were measured, and the transmittance was 6.16. %, The phase shift amount was 178.1 degrees.

Next, a first film (light-shielding film) composed of two layers, a lower layer and an upper layer, was formed on the third film. Specifically, in a single-wafer sputtering apparatus, a CrOCN film (lower layer) is formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, carbon dioxide, nitrogen, and helium using a chromium (Cr) target. A film was formed with a thickness of 47 nm. Next, on the lower layer, a CrN film (upper layer) with a film thickness of 5 nm was formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon and nitrogen using a chromium (Cr) target with a single-wafer sputtering apparatus. The film was formed in. The optical density of the laminated structure of the halftone phase shift film and the light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the first film on the third film, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the first film in a state of being laminated on the third film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Next, a second film (hardmask film) was formed on the first film. Specifically, in a single-wafer sputtering apparatus, a SiO ₂ film (second film) is formed with a film thickness of 5 nm by high-frequency sputtering (RF sputtering) in a mixed gas atmosphere of argon and oxygen using a SiO ₂ target. Filmed.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). In addition, using a spectrophotometer (Hitachi High Technology, U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 6 below shows the structure, film material, optical characteristics, and film forming conditions of the mask blank of Example 6 produced above.

FIG. 12 shows a reflectance spectrum in a state in which no other film is laminated on the first film of the mask blank produced in Example 6, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 12, in the mask blank produced in Example 6, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 32.0%, which is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 32.6%, and the difference was −0.6%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 29.1% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 29.6%, and the difference was −0.5%.

FIG. 13 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 6.

From FIGS. 12 and 13, in a mask blank having a structure in which a first film (light-shielding film) and a second film (hard mask film) are laminated in this order on a translucent substrate, on the first film. From the surface reflectance of the second film to the light of the predetermined wavelength in the state where the second film is laminated, to the light of the predetermined wavelength of the first film in the state where the other film is not laminated on the first film. When the difference calculated by subtracting the surface reflectance is 10% or less, it was detected by the defect inspection of the second film at the same position as the defect than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect tends to be larger.

Further, when the surface reflectance of the second film is 20% or more in the state where the second film is laminated on the first film, the defect size is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect detected by the defect inspection of the second film tends to be larger at the same position as the defect.

Further, the surface reflectance of the first film in the state where the other film is not laminated on the first film, and the surface reflectance of the second film in the state where the second film is laminated on the first film. When the surface reflectances are all 35% or less, the size of the defect detected by the defect inspection of the second film at the same position as the defect is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size tends to be larger.

Further, such a tendency of defect size is the same even when a third film (halftone phase shift film) is interposed between the translucent substrate and the first film. I understand.

(Example 7)
In Example 7, first, a first film (binary light-shielding film) composed of two layers, a lower layer and an upper layer, was formed on a translucent substrate made of synthetic quartz glass. Specifically, using a single-wafer sputtering apparatus, using a mixed target of molybdenum (Mo) and silicon (Si) (atomic% ratio Mo: Si = 13: 87), in a mixed gas atmosphere of argon and nitrogen. A MoSiN film (lower layer) was formed with a film thickness of 47 nm by reactive sputtering (DC sputtering). Next, on the lower layer, a mixing target of molybdenum (Mo) and silicon (Si) (atomic% ratio Mo: Si = 13: 87) is used in a single-wafer sputtering apparatus to mix argon, nitrogen, and helium. A MoSiN film (upper layer) was formed with a film thickness of 13 nm by reactive sputtering (DC sputtering) in a gas atmosphere. The optical density of this light-shielding film with respect to ArF exposure light (wavelength 193 nm) was 3 or more.

After forming the first film on the translucent substrate, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). In addition, the surface reflectance of the first film with respect to light having a wavelength of 200 nm to 800 nm was measured using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100).

Next, a second film (hardmask film) was formed on the first film. Specifically, a CrN film (second film) is formed with a film thickness of 5 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon and nitrogen using a Cr target in a single-wafer sputtering apparatus. did.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). In addition, using a spectrophotometer (Hitachi High Technology, U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 7 below shows the structure, film material, optical properties, and film forming conditions of the mask blank of Example 7 produced above.

FIG. 14 shows a reflectance spectrum in a state in which no other film is laminated on the first film of the mask blank produced in Example 7, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 14, in the mask blank produced in Example 7, the first film is based on the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was about 10% or less.

In particular, the difference in surface reflectance was small with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 37.9%, and is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 31.0%, and the difference was 6.9%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 41.0% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 36.0%, and the difference was 5.0%.

FIG. 15 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Example 7.

From FIGS. 14 and 15, in a mask blank having a structure in which a first film (binary light-shielding film) and a second film (hard mask film) are laminated in this order on a translucent substrate, on the first film. From the surface reflectance of the second film with respect to the light of the predetermined wavelength in the state where the second film is laminated, the light of the predetermined wavelength of the first film in the state where the other film is not laminated on the first film. When the difference calculated by subtracting the surface reflectance with respect to is 10% or less, it is detected by the defect inspection of the second film at the same position as the defect than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect tends to be larger.

Further, when the surface reflectance of the second film is 20% or more in the state where the second film is laminated on the first film, the defect size is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size of the defect detected by the defect inspection of the second film tends to be larger at the same position as the defect.

Further, the surface reflectance of the first film in the state where the other film is not laminated on the first film, and the surface reflectance of the second film in the state where the second film is laminated on the first film. When the surface reflectances are all 35% or less, the size of the defect detected by the defect inspection of the second film at the same position as the defect is larger than the defect size detected by the defect inspection of the first film. It can be seen that the size tends to be larger.

(Comparative Example 1)
In Comparative Example 1, first, a mixing target (atomic% ratio Mo: Si = 21) of molybdenum (Mo) and silicon (Si) was used on a translucent substrate made of synthetic quartz glass using a single-wafer sputtering apparatus. : 79) was used to form a first film (halftone phase shift film) made of MoSiN with a film thickness of 92 nm by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon, nitrogen and helium. When the transmittance and the phase shift amount of this halftone phase shift film with respect to the wavelength of 248 nm, which is the wavelength of the KrF exposure light, were measured using a phase shift amount measuring device (MPM248 manufactured by Lasertech), the transmittance was 5.52. %, The phase shift amount was 177.5 degrees.

After forming the first film on the translucent substrate, the position and size of the defect of the first film were measured using a defect inspection device (Lasertec, M1320). In addition, the surface reflectance of the first film with respect to light having a wavelength of 200 nm to 800 nm was measured using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100).

Next, a second film (light-shielding film) composed of three layers, a lower layer, an intermediate layer, and an upper layer, was formed on the first film. Specifically, a CrN film (lower layer), a CrC film (intermediate layer), and a CrON film (upper layer) were continuously formed by reactive sputtering (DC sputtering) using a chrome (Cr) target by an in-line sputtering device. .. The film thickness of the lower layer and the intermediate layer was 55 nm, and the film thickness of the upper layer was 18 nm.

After forming the second film on the first film, the position and size of the defect of the second film were measured using a defect inspection device (Lasertec, M1320). Further, using a spectrophotometer (Hitachi High Technology Co., Ltd., U-4100), the surface reflectance of the second film in a state of being laminated on the first film with respect to light having a wavelength of 200 nm to 800 nm was measured.

Table 8 below shows the structure, film material, optical characteristics, and film forming conditions of the mask blank of Comparative Example 1 produced above.

FIG. 16 shows a reflectance spectrum in a state in which no other film is laminated on the first film of the mask blank produced in Comparative Example 1, and a state in which the second film is laminated on the first film. The reflectance spectra in the above are shown respectively.
As shown in FIG. 16, in the mask blank produced in Comparative Example 1, the first film was obtained from the surface reflectance of the second film with respect to light of a predetermined wavelength in a state where the second film was laminated on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to the light of a predetermined wavelength in the state where the other film was not laminated on the film was generally larger than 10%.

In particular, the difference in surface reflectance was large with respect to light having a wavelength of 488 nm to 532 nm. For example, with respect to light having a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is laminated on the first film is 36.2%, which is on the first film. The surface reflectance of the first film in the state where the other films were not laminated was 11.2%, and the difference was 25.0%. The surface reflectance of the second film in the state where the second film is laminated on the first film is 39.1% with respect to light having a wavelength of 532 nm, and the other film is on the first film. The surface reflectance of the first film in the state where the films were not laminated was 14.1%, and the difference was 25.0%.

FIG. 17 is a graph showing the results of comparing the defect size of the first film and the defect size of the second film detected at the same coordinates by the defect inspection on the mask blank produced in Comparative Example 1.

From FIGS. 16 and 17, the surface reflectance of the light-shielding film in the state where the light-shielding film (second film) is laminated on the phase-shift film (first film) shows that the light-shielding film is not laminated (phase). If the difference calculated by subtracting the surface reflectance of the phase shift film (when the surface of the shift film is exposed) is larger than 10%, it is the same as the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the defect detected by the defect inspection of the light-shielding film tends to be smaller at the position.

Further, at least one of the surface reflectance of the phase shift film in the state where the other film is not laminated on the phase shift film and the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film are If it is larger than 35%, the size of the defect detected by the light-shielding film defect inspection at the same position as the defect tends to be smaller than the defect size detected by the defect inspection of the phase shift film. I understand.

10 Mask blank 12 First film 14 Second film 20 Translucent substrate

Claims (12)

A mask blank having a structure in which a translucent film and a light-shielding film are laminated in this order on a translucent substrate.
The light-shielding film is composed of two or more laminated films and is made of a material containing chromium.
The light semi-transmissive film is made of a material containing silicon,
The refractive index n of the light transflective film in light having a wavelength of 488 nm and a wavelength of 532 nm is smaller than the refractive index n in light of any layer of the light-shielding film.
A mask blank characterized in that the extinction coefficient k of the light transflective film in the light is smaller than the extinction coefficient k of any layer of the light-shielding film in the light. The mask blank according to claim 1, wherein the refractive index n of the light-shielding film in the light is 2.64 or more. The mask blank according to claim 1 or 2, wherein the extinction coefficient k of the light-shielding film in the light is 0.44 or more. The light-shielding film is composed of two layers, a lower layer and an upper layer. The refractive index n of the upper layer in the light is smaller than the refractive index n of the light in the lower layer, and the extinction coefficient k of the upper layer in the light is The mask blank according to any one of claims 1 to 3, wherein the lower layer has an extinction coefficient k larger than that of the light. The mask blank according to claim 4, wherein the thickness of the lower layer is thicker than the thickness of the upper layer. The mask blank according to claim 4 or 5, wherein the lower layer is formed of a material containing chromium, oxygen, nitrogen and carbon, and the upper layer is formed of a material containing chromium and nitrogen. .. The light-shielding film is composed of three layers, a lower layer, an intermediate layer, and an upper layer. The refractive index n in the light is smaller in the order of the upper layer, the lower layer, and the intermediate layer, and the extinction coefficient k in the light is the upper layer, the lower layer, and the intermediate layer. The mask blank according to any one of claims 1 to 3, wherein the mask blanks are smaller in the order of layers. The lower layer is formed of a material containing chromium, oxygen, nitrogen and carbon, the intermediate layer is formed of a material containing chromium and nitrogen, and the upper layer is a material containing chromium, oxygen, nitrogen and carbon. The mask blank according to claim 7, wherein the mask blank is formed of. The mask blank according to any one of claims 1 to 8, wherein the light transmissive film has a transmittance of 1% or more with respect to the exposure light of the ArF excimer laser. The light semi-transmissive film has a predetermined position with respect to the exposure light of the ArF excimer laser that has passed through the light semi-transmissive film and the exposure light that has passed through the air at the same distance as the thickness of the light semi-transmissive film. The mask blank according to any one of claims 1 to 9, wherein the mask blank has a function of causing a phase difference. The mask blank according to any one of claims 1 to 10, wherein the optical density of the ArF excimer laser in the laminated structure of the light transflective film and the light-shielding film with respect to the exposure light is 2.5 or more. A transfer mask according to any one of claims 1 to 11, wherein a first pattern is formed on the light transflective film and a second pattern is formed on the light-shielding film.

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