JP6279858B2 - Mask blank manufacturing method and transfer mask manufacturing method - Google Patents

Description

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

In general, a mask blank serving as an original of a transfer mask used in photolithography is manufactured by forming a thin film for pattern formation on a light-transmitting substrate such as synthetic quartz glass by a sputtering method. The mask blank thin film is ideally free from black defects and white defects, but a certain number of defects are allowed in practice in consideration of yield and the like. When producing a transfer mask from a mask blank in which a defect exists in the thin film, the arrangement of the pattern on the plane is adjusted so that each defect does not affect the exposure transfer. Therefore, for example, the defect inspection apparatus as disclosed in Patent Document 1 is used to perform defect inspection on the thin film of the mask blank, and for all the defects detected in the thin film, the type and position coordinates thereof. Is recorded in association with the mask blank.
On the other hand, in the case of a mask blank used for manufacturing a halftone 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 light-transmitting substrate, There are many cases to do.

Japanese 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 light-transmitting substrate by applying a sputtering method, and a defect inspection is performed on the phase shift film. Then, a light shielding film is formed on the phase shift film by sputtering, and a defect inspection is performed on the light shielding film. In general, when a light shielding film is formed on a defect present in a phase shift film, the shape of the phase shift film defect 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 by the phase shift film defect inspection and the size of the defect detected at the same position as the phase shift film defect in the light shielding film defect inspection after the light shielding film is formed are not necessarily the same. It will not be. If the defect size detected by the defect inspection of the light shielding film at the same position as the defect tends to be larger than the defect size detected by the defect inspection of the phase shift film, the defect inspection of the phase shift film Since the possibility that the defect that could not be detected can be found by the defect inspection of the light shielding film is increased, it can be said to be a preferable mask blank configuration.

  However, depending on the combination of the phase shift film and the light shielding film, the structure opposite to the preferred mask blank structure, that is, the size of the light shielding film at the same position as the defect, rather than the defect size detected in the phase shift film defect inspection In some cases, the size of the defect detected by the defect inspection becomes smaller, which is a problem.

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

In order to achieve the above object, the present invention has the following configuration.
(Configuration 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 with respect to light of a predetermined wavelength in a state where the second film is stacked on the first film, in a state where no other film is stacked on the first film. The difference calculated by subtracting the surface reflectance of the first film with respect to light of a predetermined wavelength is 10% or less.

(Configuration 2)
2. The mask blank according to Configuration 1, wherein the predetermined wavelength is 488 nm to 532 nm.
(Configuration 3)
The surface reflectance of the second film with respect to light having a predetermined wavelength in a state in which the second film is stacked on the first film is 20% or more. Mask blank.

(Configuration 4)
The surface reflectance of the first film with respect to light of a predetermined wavelength when no other film is stacked on the first film, and the second film is stacked on the first film. 4. The mask blank according to any one of configurations 1 to 3, wherein the surface reflectance of the second film with respect to light of a predetermined wavelength is 35% or less.

(Configuration 5)
5. The mask blank according to any one of configurations 1 to 4, wherein the first film is a light semi-transmissive film having a transmittance with respect to exposure light of 1% or more.
(Configuration 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 that has passed through the air at the same distance as the thickness of the light semi-transmissive film. The mask blank according to Configuration 5, characterized by comprising:

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

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

(Configuration 11)
11. The mask according to claim 1, 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.
(Configuration 12)
12. A transfer mask, wherein 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. .

(Configuration 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,
Forming a first film by a sputtering method on a light-transmitting substrate;
A first defect inspection step for inspecting the first film formed on the translucent substrate by irradiating inspection light to inspect the defect;
Forming a second film on the first film by a sputtering method;
A second defect inspection step for inspecting the second film formed on the first film by irradiating inspection light to inspect the defect;
The first film and the second film are obtained from a surface reflectance of the second film with respect to light having a predetermined wavelength in a state where the second film is stacked on the first film. It is formed under the condition that the difference calculated by subtracting the surface reflectance of the first film with respect to light of a predetermined wavelength when no other film is stacked on the film is 10% or less. Mask blank manufacturing method.

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

(Configuration 16)
The first film and the second film include a surface reflectance of the first film with respect to light of a predetermined wavelength in a state where no other film is stacked on the first film, and the first film. Any one of Structures 13 to 15, wherein the second film is formed under a 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 stacked thereon. The manufacturing method of the mask blank of crab.
(Configuration 17)
The method for manufacturing a mask blank according to any one of Structures 13 to 16, wherein the light having the predetermined wavelength is the inspection light.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the mask blank which can make a defect easier to detect in a defect inspection, the mask for transfer, and a mask blank can be provided.

It is sectional drawing which shows an example of a mask blank. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 1 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 1, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 2 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 2, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 3 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 3, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 4 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 4, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 5 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 5, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 6 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 6, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in Example 7 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in Example 7, and the defect size of the 2nd film | membrane. The reflectance spectrum of the 1st film | membrane and 2nd film | membrane of the mask blank produced in the comparative example 1 is shown. It is a graph which shows the result of having compared the defect size of the 1st film | membrane of the mask blank produced in the comparative example 1, and the defect size of the 2nd film | membrane.

  The inventor conducted a defect inspection on the mask blanks of various combinations of phase shift films and light-shielding films, and conducted intensive studies. 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, rather than the size of the defect detected in the defect inspection of the phase shift film, It has been 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 in a state where the light shielding film is laminated on the phase shift film, the phase shift film in a 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 rather than the defect size detected by the defect inspection of the phase shift film I found that tends to be larger.

  In addition, 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 is detected at the same position as the defect than the defect size detected by the defect inspection of the phase shift film. It has been found that the size of the defect detected by the defect inspection of the light shielding film tends to be larger.

  Furthermore, the surface reflectance of the phase shift film when no other film is laminated on the phase shift film and the surface reflectance of the light shielding film when the light shielding film is laminated on the phase shift film are both 35. % Or less, the defect size detected by the defect inspection of the light shielding film at the same position as the defect tends to be larger than the defect size detected by the defect inspection of the phase shift film. 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 any other film or the phase shift film. This is different from the surface reflectance of the light shielding film laminated on the other film. Therefore, even if the surface reflectance of these light-shielding films is described in known literatures, it cannot be a motivation for those skilled in the art to arrive at the present invention.

  In addition, the defect size tendency as described above is not limited to a mask blank having a laminated structure of a phase shift film and a light shielding film, but also in a mask blank having a laminated structure of a combination of two or more other films. It was 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, the second film in a state where the second film is laminated on the first film. The difference calculated by subtracting the surface reflectance for light of a predetermined wavelength of the first film in a state where no other film is laminated on the first film from the surface reflectance for light of the predetermined wavelength is 10% or less. In some cases, the size of the defect detected by the defect inspection of the second film 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. It was found.

  Furthermore, it has been found that the same tendency is found when another film is 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 stacked in this order on a translucent substrate, the second film is stacked on the first film. The difference calculated by subtracting the surface reflectance for light of a predetermined wavelength of the first film in a state where no other film is laminated on the first film from the surface reflectance of light of the second film for the predetermined wavelength. 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. A trend was found.

  Hereinafter, a mask blank, a transfer mask, and a method for manufacturing a mask blank according to an 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 this embodiment has a structure in which a first film 12 and a second film 14 are laminated in this order on a translucent substrate 20. Both the first film 12 and the second film 14 are formed of a material containing one or more elements of metal and silicon.

  A state in which no other film is laminated on the first film 12 based on 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 ( The difference calculated by subtracting the surface reflectance of the first film 12 with respect to light of a predetermined wavelength in the state in which the first film 12 is exposed is preferably 10% or less, and is −10% or more and + 10% or less ( More preferably, the absolute value is 10% or less.

The mask blank of this embodiment can be preferably applied in the case of the following configurations, for example.
(1) In the case of a mask blank provided with a light semi-transmissive film In addition to a halftone phase shift film that transmits exposure light at a predetermined transmittance and produces a predetermined phase difference, the light semi-transmissive film is exposed to exposure light. Some films are mainly used in enhancer-type masks that have optical characteristics that allow transmission with a predetermined transmittance but do not cause a phase difference in the transmitted light. In the case of a mask blank including any light semi-transmissive film, a light shielding film for forming a light shielding band is often required. For this reason, a structure in which a light semi-transmissive film and a light-shielding film are sequentially stacked on a light-transmitting substrate is often provided. The light semi-transmissive film is the first film 12, the light-shielding film is the second film 14, and satisfies the above-described relationship between the first film and the second film of the present invention, and each film is Materials that form the light semi-transmissive film and the light-shielding film may be selected 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 described above The materials for the light-shielding film and the hard mask film may be selected so as to satisfy the relationship with the second film and satisfy the functions (optical characteristics, etching characteristics, etc.) originally required for each film.

  In the case of the structure provided with the etching stopper film between the translucent substrate and the light semi-transmissive film, the etching stopper film (first film 12) and the light semi-transmissive film (second film 14) are shown above. In addition, the etching stopper film and the light semi-transparent film satisfy the relationship between the first film and the second film of the present invention and satisfy the functions (optical characteristics, etching characteristics, etc.) originally required for each film. It is advisable to select a material for the membrane.

  In the case where 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 formed as described above. In order to satisfy the relationship between the first film and the second film of the invention and to satisfy the functions (optical characteristics, etching characteristics, etc.) originally required for each film, the light semi-transmissive film and the etching stopper film Each material should be selected. In addition, 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 described above, and each The material of the etching stopper film and the light shielding film may be selected so that the film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

  Examples of the material forming the light semi-transmissive film include a material containing silicon without containing a transition metal, and a material containing transition metal and silicon (hereinafter collectively referred to as a silicon-based material). It is 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 exposure light with a predetermined transmittance, it is preferable that the light semi-transmissive film contains one or more elements selected from oxygen and nitrogen.

  In the case of a mask blank configuration in which a light-shielding film is provided in contact with the light-semitransmissive film, the material for forming the light-shielding film is a sufficient etching selection for the etching gas used when patterning the light-semitransmissive 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). This chromium-based material is preferably chromium alone or a material containing one or more elements selected from oxygen, nitrogen, carbon, hydrogen, fluorine and boron in chromium. A material containing at least one element selected from hafnium and zirconium in tantalum (hereinafter referred to as TaHf-based material) is also preferable. In the case of providing a hard mask film on a 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 providing an etching stopper film between the light semi-transmissive 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 material containing tantalum (hereinafter referred to as a tantalum-based material). This tantalum-based material is preferably a material containing one or more elements selected from nitrogen, oxygen, carbon, hydrogen and boron in tantalum. In the case where the light shielding film is formed of a silicon material and a hard mask film is provided on the light shielding film, the hard mask film is preferably formed of a chromium material or a TaHf material.

  On the other hand, in the case of an etching stopper film between the light transmissive substrate and the light semi-transmissive film, the etching stopper film has etching selectivity between both the light transmissive substrate and the light semi-transmissive 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 A binary mask blank often has a structure in which a light shielding film and a hard mask film are sequentially laminated 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 described above, and each film The materials for the light shielding film and the hard mask film may be selected so as to satisfy the originally required functions (optical characteristics, etching characteristics, etc.). In particular, when a binary mask blank suitable for a substrate-digged 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 described above, and The materials of the etching stopper film and the light shielding film may be selected so that each film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

  As a material for forming the light-shielding film of the binary mask blank, a chromium-based material, 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 the case where a light shielding film is formed of a chromium material and a hard mask film is provided on the light shielding film, a silicon material, a tantalum material, or a TaHf material can be applied to the hard mask film. When a light shielding film is formed of a transition metal silicide material and a hard mask film is provided on the light shielding film, a chromium material, a tantalum material, or a TaHf material can be applied to the hard mask film. In the case where a light shielding film is formed of a tantalum material and a hard mask film is provided on the light shielding film, a chromium material can be applied to the hard mask film.

(3) In the case of a reflective mask blank The reflective mask blank has a configuration in which a multilayer reflective film that reflects exposure light on a substrate, a protective film that protects the multilayer reflective film, and an absorber film that forms a transfer pattern are laminated in this order. It is equipped with. Further, there are 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 described above, and The effects of the present invention can be obtained by selecting materials for the protective film and the absorber film so that the film satisfies the originally required functions (optical characteristics, etching characteristics, etc.).

The buffer 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 described above, and each film The materials for the buffer film and the absorber film may be selected so as to satisfy the originally required functions (optical characteristics, etching characteristics, etc.).
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 described above, and The materials of the absorber film and the hard mask film may be selected 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 as exposure light, a material containing ruthenium is suitable for the protective film, and a tantalum material or TaHf material is particularly preferred for the absorber film. Used. In the case where an absorber film is formed of a tantalum material and a hard mask film is provided on the absorber film, a chromium material can be applied to the hard mask film.
When 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 used for the buffer film.

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

  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 light semi-transmissive film having a transmittance for exposure light of 1% or more.
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 passed 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 a material include MoSiN.

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 transfer mask transfer pattern is formed. It is because it can suppress that the resist film on a semiconductor wafer is influenced by the exposure light which permeate | transmitted other outer peripheral area | regions.

  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, or a film structure having a composition gradient 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, low thermal expansion glass (SiO ₂ —TiO ₂ glass, etc.). Etc. Synthetic quartz glass has a high transmittance with respect to 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 transfer mask of the present invention, ArF excimer laser light, KrF excimer laser light, i-line light, etc. can be used, and there is no particular limitation, but ArF excimer laser light is used. Is preferably used.

(Transfer mask)
The transfer mask can be manufactured by forming the first pattern on the first film 12 of the mask blank 10 described above and forming the 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 the first pattern is formed on the second film 14 by dry etching using a mixed gas of chlorine-based gas and oxygen gas. To do. Next, after removing 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. Form. Next, a resist film having a second pattern is formed on the surface of the second film 14, and the second pattern is formed on the second film 14 by dry etching using a mixed gas of chlorine-based gas and 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 manufactured 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 same as those of 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 manufacturing method of the mask blank of this embodiment includes the following steps.
(1) A step of forming the first film 12 on the translucent substrate 20 by a sputtering method.
(2) A first defect inspection process for inspecting the first film 12 formed on the translucent substrate 20 by irradiating inspection light.
(3) A step of forming the second film 14 on the first film 12 by a sputtering method.
(4) A second defect inspection process for inspecting the second film 14 formed on the first film 12 by irradiating the inspection light with a defect.

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

  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 include the surface reflectance of the first film 12 with respect to light of a predetermined wavelength in a state where no other film is stacked 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 surface 12 is 35% or less.

The light having the predetermined wavelength is preferably inspection light from a 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 apparatus 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 more specifically 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), a first film (halftone phase shift film) made of MoSiN was formed in a 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 (Lasertec MPM193), the transmittance and phase shift amount of the halftone phase shift film with respect to light having a wavelength of 193 nm, which is the wavelength of ArF exposure light, were measured, and the transmittance was 6.16. %, And the phase shift amount was 178.1 degrees.

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

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

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

  Table 1 below shows the configuration, film material, optical characteristics, and film formation conditions of the mask blank of Example 1 manufactured above. In addition, about each optical characteristic (refractive index n and extinction coefficient k) with respect to the light of wavelength 488nm and wavelength 532nm of a 1st film | membrane and a 2nd film | membrane, an optical thin film characteristic measuring apparatus (n & k technology company, n & k1280) is used. Used to calculate. However, one in which only the first film is formed on the light-transmitting substrate and one in which only the second film is formed on the light-transmitting substrate are separately prepared, and these are used to form the first film and the second film. Each optical characteristic is calculated. This calculation of optical characteristics is the same in the following examples and comparative examples.

FIG. 2 shows a reflectance spectrum in a state where no other film is laminated on the first film of the mask blank produced in Example 1, and a state where the second film is laminated on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 2, in the mask blank manufactured in Example 1, the first film reflects the surface reflectance of the second film with respect to light having a predetermined wavelength in the state where the second film is stacked on the first film. 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 was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 28.4%. The surface reflectance of the first film in a state where no other film was laminated was 26.3%, and the difference was 2.1%. For light with a wavelength of 532 nm, the surface reflectance of the second film in the state where the second film is stacked on the first film is 29.7%. The surface reflectance of the first film in a state where the films were not stacked was 28.4%, and the difference was 1.3%.

  FIG. 3 is a graph showing a result 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 for the mask blank produced in Example 1. The graph of FIG. 3 is obtained by accumulating the defect size data of a plurality of mask blanks, not the defect size data of one mask blank. In FIG. 3, the horizontal axis indicates the size of the defect detected in the first film. The vertical axis represents the size of the defect detected in the second film. The square dots indicate pinholes (concave defects). A round dot indicates a particle (convex defect). 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 straight line Y = X is that the second film is larger than the defect size detected in the first film. This indicates that the size of the defect detected in is large. On the contrary, the point located below the straight line Y = X 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 way of viewing the defect size graph (scatter diagram) is the same.

  2 and 3, the phase shift in the state where the light shielding film is not laminated (the surface of the phase shift film is exposed) from the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film. If 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 rather than the defect size detected by the defect inspection of the phase shift film It can be seen that the size of tends to be larger.

  In addition, 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 is detected at the same position as the defect than the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the defect detected in the defect inspection of the light shielding film tends to be larger.

  Furthermore, the surface reflectance of the phase shift film when no other film is laminated on the phase shift film and the surface reflectance of the light shielding film when the light shielding film is laminated on the phase shift film are both 35. % Or less, the defect size detected by the defect inspection of the light shielding film at the same position as the defect tends to be larger than the defect size detected by the defect inspection of the phase shift film. .

(Example 2)
In Example 2, 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), a first film (halftone phase shift film) made of MoSiN was formed in a 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 (Lasertec MPM193), the transmittance and phase shift amount of the halftone phase shift film with respect to light having a wavelength of 193 nm, which is the wavelength of ArF exposure light, were measured, and the transmittance was 6.16. %, And the phase shift amount was 178.1 degrees.

  After the first film was formed on the light-transmitting substrate, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

  Next, a second film (light-shielding film) composed of 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 chromium (Cr) target by an in-line sputtering apparatus. . The total film thickness of the lower layer and the intermediate layer was formed to be 26 nm, and the upper layer was formed to have a film thickness of 22 nm. The optical density with respect to ArF exposure light (wavelength 193 nm) in the laminated structure of the halftone phase shift film and the light shielding film was 3 or more.

  After the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

  Table 2 below shows the configuration, film material, optical characteristics, and film formation conditions of the mask blank of Example 2 manufactured above.

FIG. 4 shows the reflectance spectrum in a state where no other film is laminated on the first film of the mask blank produced in Example 2, and the state where the second film is laminated on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 4, in the mask blank produced in Example 2, the first film reflects the surface reflectance of the second film with respect to light having a predetermined wavelength in the state where the second film is stacked on the first film. 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 was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 24.7%. The surface reflectance of the first film in a state where no other film was stacked was 26.3%, and the difference was −1.6%. For light with a wavelength of 532 nm, the surface reflectance of the second film in the state where the second film is stacked on the first film is 27.6%. The surface reflectance of the first film in a state where the films were not stacked was 28.4%, and the difference was −0.8%.

  FIG. 5 is a graph showing a result 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 for the mask blank produced in Example 2.

  4 and 5, from the surface reflectance of the light shielding film in a 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). If 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 rather than the defect size detected by the defect inspection of the phase shift film It can be seen that the size of tends to be larger.

  In addition, 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 is detected at the same position as the defect than the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the defect detected in the defect inspection of the light shielding film tends to be larger.

  Furthermore, the surface reflectance of the phase shift film when no other film is laminated on the phase shift film and the surface reflectance of the light shielding film when the light shielding film is laminated on the phase shift film are both 35. % Or less, the defect size detected by the defect inspection of the light shielding film at the same position as the defect tends to be larger than the defect size detected by the defect inspection of the phase shift film. .

(Example 3)
In Example 3, 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), a first film (halftone phase shift film) made of MoSiN was formed in a 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 (Lasertec MPM193), the transmittance and phase shift amount of the halftone phase shift film with respect to light having a wavelength of 193 nm, which is the wavelength of ArF exposure light, were measured, and the transmittance was 6.16. %, And the phase shift amount was 178.1 degrees.

  After the first film was formed on the light-transmitting substrate, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

  Next, a second film (light-shielding film) composed of a lower layer and an upper layer was formed on the first film. Specifically, 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 in a single wafer sputtering apparatus. The film was formed with a thickness of 47 nm. Next, a CrN film (upper layer) having a thickness of 5 nm is formed on the lower layer 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. The optical density with respect to ArF exposure light (wavelength 193 nm) in the laminated structure of the halftone phase shift film and the light shielding film was 3 or more.

  After the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

  Table 3 below shows the configuration, film material, optical characteristics, and film formation conditions of the mask blank of Example 3 manufactured above.

6 shows a reflectance spectrum in a state where no other film is laminated on the first film of the mask blank produced in Example 3, and a state where the second film is laminated on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 6, in the mask blank manufactured in Example 3, the first film reflects the surface reflectance of the second film with respect to light having a predetermined wavelength in the state where the second film is stacked on the first film. 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 was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 32.6%. The surface reflectance of the first film in a state where no other film was stacked was 26.3%, and the difference was 6.3%. With respect to light having a wavelength of 532 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 29.6%. The surface reflectance of the first film in a state where the films were not stacked was 28.4%, and the difference was 1.2%.

  FIG. 7 is a graph showing a result 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 for the mask blank produced in Example 3.

  6 and 7, the phase shift in the state where the light shielding film is not laminated (the surface of the phase shift film is exposed) from the surface reflectance of the light shielding film in the state where the light shielding film is laminated on the phase shift film. If 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 rather than the defect size detected by the defect inspection of the phase shift film It can be seen that the size of tends to be larger.

  In addition, 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 is detected at the same position as the defect than the defect size detected by the defect inspection of the phase shift film. It can be seen that the size of the defect detected in the defect inspection of the light shielding film tends to be larger.

  Furthermore, the surface reflectance of the phase shift film when no other film is laminated on the phase shift film and the surface reflectance of the light shielding film when the light shielding film is laminated on the phase shift film are both 35. % Or less, the defect size detected by the defect inspection of the light shielding film at the same position as the defect tends to be larger than the defect size detected by the defect inspection of the phase shift film. .

Example 4
In Example 4, first, a mixed target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) is used on a light-transmitting substrate made of synthetic quartz glass by using a single wafer sputtering apparatus. 89), and a third film (halftone phase shift film) made of MoSiN was formed to a 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 (Lasertec MPM193), the transmittance and phase shift amount of the halftone phase shift film with respect to light having a wavelength of 193 nm, which is the wavelength of ArF exposure light, were measured, and the transmittance was 6.16. %, And the phase shift amount was 178.1 degrees.

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

  After the first film was formed on the third film, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane in the state laminated | stacked on the 3rd film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

  Next, a second film (hard mask film) was formed on the first film. Specifically, 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 in a single wafer sputtering apparatus. The film was formed with a thickness of 15 nm.

  After the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

  Table 4 below shows the configuration, film material, optical characteristics, and film formation conditions of the mask blank of Example 4 manufactured above.

FIG. 8 shows a reflectance spectrum in a state where 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 spectrum in each is shown.
As shown in FIG. 8, in the mask blank produced in Example 4, the first film reflects the surface reflectance of the second film with respect to light of a predetermined wavelength in the 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 light of a predetermined wavelength in a state where no other film is laminated on the film was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 22.2%, The surface reflectance of the first film in a state where no other film was laminated was 28.4%, and the difference was −6.2%. For light with a wavelength of 532 nm, the surface reflectance of the second film in the state where the second film is stacked on the first film is 24.0%, The surface reflectance of the first film in a state where the films were not stacked was 29.7%, and the difference was −5.7%.

  FIG. 9 is a graph showing a result 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 for the mask blank produced in Example 4.

  8 and 9, 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 light-transmitting substrate is formed on the first film. From the surface reflectance of the second film with respect to the light having the predetermined wavelength in the state in which the second film is laminated, with respect to the light with the predetermined wavelength in the first film in the state where no other film is laminated on the first film. When the difference calculated by subtracting the surface reflectance is 10% or less, it is detected by the defect inspection of the second film at the same position as the defect rather than the defect size detected by the defect inspection of the first film. It can be seen that the defect size tends to be larger.

  In addition, when the surface reflectance of the second film in a state where the second film is stacked on the first film is 20% or more, than the defect size detected in 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 become larger at the same position as the defect.

  Furthermore, the surface reflectance of the first film when no other film is stacked on the first film, and the second film when the second film is stacked on the first film. When both surface reflectances are 35% or less, the defect size 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 turns out that there is a tendency to become larger.

  Moreover, the tendency of such defect size is the same even when the 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) is used on a translucent substrate made of synthetic quartz glass by using a single wafer sputtering apparatus. 89), and a third film (halftone phase shift film) made of MoSiN was formed to a 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 (Lasertec MPM193), the transmittance and phase shift amount of the halftone phase shift film with respect to light having a wavelength of 193 nm, which is the wavelength of ArF exposure light, were measured, and the transmittance was 6.16. %, And the phase shift amount was 178.1 degrees.

  Next, a first film (light-shielding film) including three layers of 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 chromium (Cr) target by an in-line sputtering apparatus. . The total film thickness of the lower layer and the intermediate layer was formed to be 26 nm, and the upper layer was formed to have a film thickness of 22 nm. The optical density with respect to ArF exposure light (wavelength 193 nm) in the laminated structure of the halftone phase shift film and the light shielding film was 3 or more.

  After the first film was formed on the third film, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane in the state laminated | stacked on the 3rd film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

  Next, a second film (hard mask film) was formed on the first film. Specifically, 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 in a single wafer sputtering apparatus. The film was formed with a thickness of 15 nm.

  After the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

  Table 5 below shows the configuration, film material, optical characteristics, and film formation conditions of the mask blank of Example 5 manufactured above.

FIG. 10 shows the reflectance spectrum when no other film is stacked on the first film of the mask blank produced in Example 5, and the state where the second film is stacked on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 10, in the mask blank produced in Example 5, the first reflectivity of the second film with respect to light of a predetermined wavelength in the state where the second film is laminated on the first film is 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 was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 16.9%. The surface reflectance of the first film in a state where no other film was stacked was 24.7%, and the difference was −7.8%. For light with a wavelength of 532 nm, the surface reflectance of the second film in the state where the second film is stacked on the first film is 20.6%. The surface reflectance of the first film in a state where the films were not stacked was 27.6%, and the difference was −7.0%.

  FIG. 11 is a graph showing the result 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 for the mask blank produced in Example 5.

  10 and 11, a mask blank having a structure in which a first film (light-shielding film) and a second film (hard mask film) are stacked in this order on a light-transmitting substrate is formed on the first film. From the surface reflectance of the second film with respect to the light having the predetermined wavelength in the state in which the second film is laminated, with respect to the light with the predetermined wavelength in the first film in the state where no other film is laminated on the first film. When the difference calculated by subtracting the surface reflectance is 10% or less, it is detected by the defect inspection of the second film at the same position as the defect rather than the defect size detected by the defect inspection of the first film. It can be seen that the defect size tends to be larger.

  In addition, when the surface reflectance of the second film in a state where the second film is stacked on the first film is 20% or more, than the defect size detected in 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 become larger at the same position as the defect.

  Furthermore, the surface reflectance of the first film when no other film is stacked on the first film, and the second film when the second film is stacked on the first film. When both surface reflectances are 35% or less, the defect size 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 turns out that there is a tendency to become larger.

  Moreover, the tendency of such defect size is the same even when the 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 mixed target (atomic% ratio Mo: Si = 11) of molybdenum (Mo) and silicon (Si) is formed on a light-transmitting substrate made of synthetic quartz glass by using a single wafer sputtering apparatus. 89), and a third film (halftone phase shift film) made of MoSiN was formed to a 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 (Lasertec MPM193), the transmittance and phase shift amount of the halftone phase shift film with respect to light having a wavelength of 193 nm, which is the wavelength of ArF exposure light, were measured, and the transmittance was 6.16. %, And the phase shift amount was 178.1 degrees.

  Next, a first film (light-shielding film) composed of two layers of a lower layer and an upper layer was formed on the third film. Specifically, 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 in a single wafer sputtering apparatus. The film was formed with a thickness of 47 nm. Next, a CrN film (upper layer) having a thickness of 5 nm is formed on the lower layer 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. The optical density with respect to ArF exposure light (wavelength 193 nm) in the laminated structure of the halftone phase shift film and the light shielding film was 3 or more.

  After the first film was formed on the third film, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane in the state laminated | stacked on the 3rd film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

Next, a second film (hard mask film) was formed on the first film. Specifically, a single-wafer sputtering apparatus is used to form a SiO ₂ film (second film) 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 the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

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

FIG. 12 shows the reflectance spectrum in the state where no other film is laminated on the first film of the mask blank produced in Example 6, and the state where the second film is laminated on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 12, in the mask blank produced in Example 6, the first reflectance of the second film in the state where the second film is laminated on the first film is determined based on the surface reflectance with respect to light of a predetermined wavelength. 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 was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 32.0%. The surface reflectance of the first film in a state where no other film was stacked was 32.6%, and the difference was −0.6%. For light with a wavelength of 532 nm, the surface reflectance of the second film in the state where the second film is stacked on the first film is 29.1%. The surface reflectance of the first film in a state where the films were not stacked was 29.6%, and the difference was −0.5%.

  FIG. 13 is a graph showing a result 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 for the mask blank produced in Example 6.

  12 and 13, a mask blank having a structure in which a first film (light-shielding film) and a second film (hard mask film) are stacked in this order on a light-transmitting substrate is formed on the first film. From the surface reflectance of the second film with respect to the light having the predetermined wavelength in the state in which the second film is laminated, with respect to the light with the predetermined wavelength in the first film in the state where no other film is laminated on the first film. When the difference calculated by subtracting the surface reflectance is 10% or less, it is detected by the defect inspection of the second film at the same position as the defect rather than the defect size detected by the defect inspection of the first film. It can be seen that the defect size tends to be larger.

  In addition, when the surface reflectance of the second film in a state where the second film is stacked on the first film is 20% or more, than the defect size detected in 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 become larger at the same position as the defect.

  Furthermore, the surface reflectance of the first film when no other film is stacked on the first film, and the second film when the second film is stacked on the first film. When both surface reflectances are 35% or less, the defect size 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 turns out that there is a tendency to become larger.

  Moreover, the tendency of such defect size is the same even when the 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 of a lower layer and an upper layer was formed on a light-transmitting substrate made of synthetic quartz glass. Specifically, using a single wafer sputtering apparatus, a mixed target of molybdenum (Mo) and silicon (Si) (atomic% ratio Mo: Si = 13: 87) is used in a mixed gas atmosphere of argon and nitrogen. A MoSiN film (lower layer) was formed to a thickness of 47 nm by reactive sputtering (DC sputtering). Next, on the lower layer, a mixed target of molybdenum (Mo) and silicon (Si) (atomic% ratio Mo: Si = 13: 87) is mixed with argon, nitrogen and helium by a single wafer sputtering apparatus. A MoSiN film (upper layer) was formed to a thickness of 13 nm by reactive sputtering (DC sputtering) in a gas atmosphere. In addition, the optical density with respect to ArF exposure light (wavelength 193 nm) in this light shielding film was 3 or more.

  After the first film was formed on the light-transmitting substrate, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

  Next, a second film (hard mask film) was formed on the first film. Specifically, a CrN film (second film) with a film thickness of 5 nm is formed 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 the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

  Table 7 below shows the configuration, film material, optical characteristics, and film forming conditions of the mask blank of Example 7 manufactured above.

FIG. 14 shows the reflectance spectrum when no other film is laminated on the first film of the mask blank produced in Example 7, and the state where the second film is laminated on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 14, in the mask blank produced in Example 7, the first reflectance is determined based on the surface reflectance of the second film with respect to light having a predetermined wavelength in the state where the second film is stacked on the first film. 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 was approximately 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, for light with a wavelength of 488 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 37.9%. The surface reflectance of the first film in a state where no other film was laminated was 31.0%, and the difference was 6.9%. For light with a wavelength of 532 nm, the surface reflectance of the second film in a state where the second film is stacked on the first film is 41.0%. The surface reflectance of the first film in a state where the films were not stacked was 36.0%, and the difference was 5.0%.

  FIG. 15 is a graph showing the result 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 for the mask blank produced in Example 7.

  14 and 15, in the mask blank having a structure in which the first film (binary light-shielding film) and the second film (hard mask film) are laminated in this order on the translucent substrate, From the surface reflectance of the second film with respect to the light having the predetermined wavelength when the second film is stacked on the first film, the light with the predetermined wavelength of the first film when no other film is stacked on the first film. When the difference calculated by subtracting the surface reflectance with respect to is less than 10%, it is detected by the defect inspection of the second film at the same position as the defect rather 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.

  In addition, when the surface reflectance of the second film in a state where the second film is stacked on the first film is 20% or more, than the defect size detected in 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 become larger at the same position as the defect.

  Furthermore, the surface reflectance of the first film when no other film is stacked on the first film, and the second film when the second film is stacked on the first film. When both surface reflectances are 35% or less, the defect size 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 turns out that there is a tendency to become larger.

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

  After the first film was formed on the light-transmitting substrate, the defect position and the size of the first film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi high technology company, U-4100).

  Next, a second film (light-shielding film) composed of 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 chromium (Cr) target by an in-line sputtering apparatus. . The total film thickness of the lower layer and the intermediate layer was formed to be 55 nm, and the upper layer was formed to have a film thickness of 18 nm.

  After the second film was formed on the first film, the defect position and the size of the second film were measured using a defect inspection apparatus (Lasertec Corporation, M1320). Moreover, the surface reflectance of the 2nd film | membrane in the state laminated | stacked on the 1st film | membrane with respect to the light with a wavelength of 200 nm to 800 nm was measured using the spectrophotometer (Hitachi High Technology company, U-4100).

  Table 8 below shows the configuration, film material, optical characteristics, and film formation conditions of the mask blank of Comparative Example 1 manufactured above.

FIG. 16 shows a reflectance spectrum in a state where no other film is laminated on the first film of the mask blank produced in Comparative Example 1, and a state where the second film is laminated on the first film. The reflectance spectrum in each is shown.
As shown in FIG. 16, in the mask blank produced in Comparative Example 1, the first film reflects the surface reflectance of the second film with respect to light of a predetermined wavelength in the state where the second film is stacked on the first film. 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 was laminated on the film was approximately larger than 10%.

  In particular, the difference in surface reflectance was large for 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 stacked on the first film is 36.2%. The surface reflectance of the first film in a state where no other film was laminated was 11.2%, and the difference was 25.0%. For light with a wavelength of 532 nm, the surface reflectance of the second film in the state where the second film is stacked on the first film is 39.1%. The surface reflectance of the first film in a state where the films were not stacked was 14.1%, and the difference was 25.0%.

  FIG. 17 is a graph showing the result 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 for the mask blank produced in Comparative Example 1.

  16 and 17, from 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), the state where the light shielding film is not laminated (phase). When the difference calculated by subtracting the surface reflectance of the phase shift film in the state where the surface of the shift film is exposed is larger than 10%, it is the same as the defect than the defect size detected in 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 when no other film is laminated on the phase shift film and the surface reflectance of the light shielding film when the light shielding film is laminated on the phase shift film is If it is larger than 35%, the defect size detected by the defect inspection of the light shielding film 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.

DESCRIPTION OF SYMBOLS 10 Mask blank 12 1st film | membrane 14 2nd film | membrane 20 Translucent substrate

Claims (10)

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,
Forming a first film by a sputtering method on a light-transmitting substrate;
A first defect inspection step for inspecting the first film formed on the translucent substrate by irradiating inspection light before the second film is formed ;
Forming a second film on the first film by a sputtering method;
A second defect inspection step for inspecting the second film formed on the first film by irradiating inspection light to inspect the defect;
The first film and the second film are obtained from the surface reflectance of the second film with respect to the inspection light in a state after the second film is formed on the first film. Formed on the condition that the difference calculated by subtracting the surface reflectance of the first film with respect to the inspection light in the state before the second film is formed on the film of 1 is 10% or less ,
Wavelength of the inspection light, mask blank manufacturing method according to claim 488nm~532nm der Rukoto. The surface reflectance for the inspection light of a first of said on the membrane a second of said at state after the film is formed the second film, according to claim 1, characterized in that at least 20% Mask blank manufacturing method. The first film and the second film have a surface reflectance with respect to the inspection light of the first film in a state before the second film is formed on the first film, and the first film The surface reflectance of the second film with respect to the inspection light in a state after the second film is formed on the film is 35% or less. 3. A method for producing a mask blank according to 1 or 2 . 4. The method of manufacturing a mask blank according to claim 1, wherein the first film is a light semi-transmissive film having a transmittance with respect to exposure light of 1% or more. 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 that has passed through the air at the same distance as the thickness of the light semi-transmissive film. The method of manufacturing a mask blank according to claim 4, comprising: 6. The second film according to claim 4, wherein the second film is a light shielding film, and an 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. Mask blank manufacturing method. The method for manufacturing a mask blank according to claim 4, wherein the exposure light is ArF excimer laser light. The method for manufacturing a mask blank according to claim 1, wherein the first film is formed of a material containing silicon and nitrogen. 9. The second film according to claim 1, wherein the second film is made of a material containing chromium and further containing one or more elements selected from oxygen, nitrogen, and carbon. Mask blank manufacturing method. A method for manufacturing a transfer mask using a mask blank manufactured by the method for manufacturing a mask blank according to claim 1,
Performing a dry etching using a resist film having a first pattern as a mask to form the first pattern on the second film;
Performing dry etching using the second film having the first pattern as a mask to form the first pattern on the first film;
A method for producing a transfer mask, comprising:

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