JP5829302B2 - Photomask blank manufacturing method and photomask manufacturing method - Google Patents

Description

The present invention relates to a photomask blank, a photomask, a manufacturing method thereof, and the like used in manufacturing a semiconductor device and the like.

Miniaturization of semiconductor devices and the like has an advantage of improving performance and functions (high-speed operation, low power consumption, etc.) and cost reduction, and miniaturization is increasingly accelerated. Lithography technology supports this miniaturization, and a transfer mask is a key technology along with an exposure apparatus and a resist material.
In recent years, development of half-pitch (hp) 45 nm to 32 nm generation, which is a design specification of semiconductor devices, has been advanced. This is a 1/1 wavelength of 193 nm of ArF excimer laser exposure light.
It corresponds to 4 to 1/6. Especially in the generation after hp45nm, super-resolution technology (Resolution Enhancement Technology: RET) such as conventional phase shift method, oblique incidence illumination method and pupil filter method
) And Optical Proximity Correction (OPC) technology has become insufficient, and ultra-high NA technology (immersion lithography) and double exposure (double patterning) are required. Yes.

The phase shift method is a method in which a predetermined phase difference is generated with respect to the exposure light transmitted through the phase shifter unit, and the resolution of the transfer pattern is improved by utilizing the light interference action.
As a photomask whose resolution is improved by the phase shift method, a substrate digging type in which a quartz substrate is dug by etching or the like to provide a shifter portion, and a phase shift film formed on the substrate is patterned to form a shifter portion. There is a type to provide.
As a photomask of the substrate digging (engraving) type, there are a Levenson type phase shift mask, an enhancer type phase shift mask, a chromeless phase shift mask, and the like. The chromeless phase shift mask includes a type in which the light shielding layer on the line is completely removed and a type in which the light shielding layer on the line is patterned (so-called zebra type). A type of Levenson type phase shift mask or chromeless phase shift mask with the light-shielding layer completely removed is also called an alternative phase shifter, which is a type of phase shift mask blank in which 100% of the exposure light passing through the phase shifter is transmitted. It is. The enhancer type phase shift mask is provided with a light shielding portion, a transmittance control portion (phase 360 ° inversion = 0 °), and a 180 ° inversion portion in which glass is dug. In either type, it is necessary to form a light-shielding band in the peripheral area (outer peripheral area) along the four sides of the photomask (reticle).
As a type of photomask in which a shifter portion is provided by patterning a phase shift film formed on a substrate, there is a halftone phase shift mask or the like.

A photomask blank for producing the above chromeless phase shift mask mask is, for example, a light shielding layer made of Cr and an outermost low reflection layer made of CrO (on a transparent substrate (
It is known to have a CrO / Cr light-shielding film in which an antireflection layer is laminated, and the total film thickness is 70 to 100 nm (see, for example, column [0005] in Patent Document 1). In addition, the manufacturing process of the chromeless phase shift mask performs the excavation of the substrate using the light shielding film pattern as an etching mask, and after removing the resist pattern used for forming the light shielding film pattern, the resist is applied again, A photomask having a light shielding band in the outer peripheral area of the substrate and a light shielding pattern in the transfer area as needed after removing the light shielding film in unnecessary places by etching after protecting the part where the light shielding film is left by performing exposure and development. Get. That is, the light shielding film has both a function as an etching mask (also referred to as a hard mask) and a function as a light shielding layer for forming a light shielding band and a light shielding pattern.
In general, to improve the CD performance of a photomask, it is effective to reduce the thickness of the light shielding film and the resist for forming the light shielding film. However, if the light shielding film is made thinner, the OD value (optical density)
Will decrease. In the above-described CrO / Cr light-shielding film, generally required OD = 3
In order to achieve the above, a total film thickness of about 60 nm is required at the minimum, and it is difficult to reduce the thickness significantly. If the light shielding film cannot be thinned, the resist cannot be thinned due to the selectivity with the resist. Therefore, a large CD improvement cannot be desired.
As a countermeasure for this, the method of Patent Document 1 has been proposed. In this method, a blank of substrate / Cr second etching mask film / MoSi light shielding film / Cr first etching mask film (also antireflection film) is used (column [0038] in the same document). Then, by using a Cr-based second etching mask film having a small film thickness, the substrate excavation is made highly accurate (see the same document [0039]).
Column). Further, by using a thin Cr-based first etching mask film, it is possible to reduce the resist thickness, and to improve the CD accuracy of the light shielding film (see the documents [0049] and [0035]).
] Column). At the same time, OD = 3 of the light-shielding film is to be ensured (see the same document [00
46]).
However, in the above method, the light shielding film and the etching mask film are formed of different materials as different films, and the etching mask film having etching selectivity more than the resist and having a significantly thin film thickness is used for etching the light shielding film. It is intended to improve the CD by becoming a mask, and is not intended to reduce the thickness of the light shielding film itself.
In addition, the above-described method is applicable to the heat treatment resistance of the light shielding film, the chemical resistance of the light shielding film (mask cleaning resistance), the film stress of each layer such as the light shielding film and the etching mask film, and the change in the substrate flatness before and after the photomask fabrication (
It is not intended to improve these with respect to (pattern position accuracy).
Unless the light-shielding film itself is thinned and the above improvement is not achieved, it cannot be applied to ultra-high NA-ArF lithography or double patterning. Necessary resolution (60 nm at hp45 nm, hp3
SRAF resolution of 42 nm is required at 2 nm. In order to obtain CD accuracy with “from ITRS 2006”), a light shielding film that can be processed with a resist film thickness of 200 nm or less, preferably 150 nm or less is required. Is difficult.

The above is also true when, for example, a photomask blank of substrate / MoSi phase shift film / Cr second etching mask film / MoSi light shielding film / Cr first etching mask film (also antireflection film) is used. The same applies (see Patent Document 2 [0174] column, etc.).
In addition, the above is a so-called binary photomask including, for example, a light shielding film having a laminated structure of MoSi-based materials, for example, a light shielding film having a laminated structure of MoSiN main light shielding layer / MoSiON antireflection layer from the substrate side. The same applies to the case (Patent Document 3).

By the way, in order to form a fine pattern having a DRAM half pitch (hp) of 45 nm or more in the semiconductor design rule, it is necessary to use an ultra-high NA exposure method having a numerical aperture of NA> 1, for example, immersion exposure.
In immersion exposure, the refractive index is 1 by filling the space between the wafer and the lowermost lens of the exposure apparatus with a liquid.
Compared with air, the exposure method can improve the resolution because the NA can be increased by the refractive index of the liquid. A numerical aperture (NA) is expressed by NA = n × sin θ. θ is an angle formed by the light beam entering the outermost side of the lowermost lens of the exposure apparatus and the optical axis, and n is a refractive index of the medium between the wafer and the lowermost lens of the exposure apparatus.
However, the immersion exposure method having a numerical aperture NA> 1 is applied, and D in the semiconductor design rule is applied.
When trying to form a fine pattern with a RAM half pitch (hp) of 45 nm or more,
It was found that there was a problem that the expected resolution and CD accuracy (including linearity) could not be obtained.
The cause is that when the pattern width of the mask pattern is made smaller than the exposure wavelength, the incident angle to the photomask (the angle between the normal of the substrate and the incident light) is small (close to normal incidence). The emission angle of the ± 1st order diffracted light exiting from the lens increases, and the ± 1st order diffracted light does not enter the lens with a finite diameter and is not resolved. In order to avoid this, when the incident angle to the photomask is increased (oblique incidence), the emission angle of the ± 1st order diffracted light emitted from the photomask is reduced, and the ± 1st order diffracted light is applied to a lens having a finite diameter. Incident light is resolved.
However, if the incident angle to the photomask is increased in this way, a problem of shielding effect (shadowing) occurs, which adversely affects the resolution. Specifically, FIG.
When the exposure light is obliquely incident on the side wall of the light shielding pattern as shown in FIG.
Shadows can be created from the dimensional structure (especially height). Due to this shadow, the size on the photomask is not accurately transferred, and the amount of light is reduced (darkened).
As described above, even when transferring to a transfer object such as a wafer using a photomask manufactured from a blank, the thinning of the pattern results in a problem of resolution reduction due to the height of the side wall of the pattern. As a solution, there is a need to thin the transfer pattern,
For this reason, it is necessary to reduce the thickness of the light shielding film.
However, in the methods described in the above cited documents 1 to 3, the light shielding layer film and the etching mask film are formed of different materials as different films, have etching selectivity over the resist, and have a greatly increased film thickness. The etching mask film serves as an etching mask for the light-shielding film as an etching mask for the thin light-shielding film, so that the CD is improved, and the light-shielding film itself is not intended to be thinned. For this reason, the transfer pattern is not sufficiently thin.
Accordingly, the provision of a photomask blank and a photomask capable of achieving the thinning of the light-shielding film (and hence the thinning of the transfer pattern) necessary for the generation of DRAM half pitch (hp) 45 nm or later, particularly the hp32-22 nm generation in the semiconductor design rule. Is difficult.
JP 2007-241136 A JP 2007-2441065 A JP 2006-78825 A

An object of the present invention is to develop a material for a generation aiming at a resist film thickness of 200 nm or less (generally hp45 nm or more), and further a resist film thickness of 150 nm or less (generally hp32 nm or more).
The present invention also provides a DRAM half pitch (hp) of 45 nm in the semiconductor design rule.
The purpose is to reduce the thickness of the light-shielding film (and thus to reduce the thickness of the transfer pattern) that can cope with the ultra-high NA technology and double patterning required for the subsequent generations, particularly the hp32-22 nm generation.
Another object of the present invention is to provide a photomask blank capable of achieving a pattern resolution of 50 nm or less on the mask.

The present invention has the following configuration.
(Configuration 1)
A photomask blank having a light-shielding film on a light-transmitting substrate used for producing a photomask for ArF excimer laser exposure, wherein the light-shielding film has a molybdenum content of 2
It is made of molybdenum silicide metal that is more than 0 atomic% and 40 atomic% or less, and the layer thickness is 40
a light-shielding layer having a thickness of less than nm, an antireflection layer formed on and in contact with the light-shielding layer and made of a molybdenum silicide compound containing at least one of oxygen and nitrogen, and a lower layer formed on and under the light-shielding layer. A photomask blank comprising a reflective layer.
(Configuration 2)
The photomask blank according to Configuration 1, wherein the antireflection layer contains more than 0 atomic% and not more than 10 atomic% of molybdenum.
(Configuration 3)
3. The photomask blank according to claim 1, further comprising an etching mask layer made of a material containing chromium as a main component, the layer being formed on and in contact with the light shielding film.
(Configuration 4)
The etching mask film is
4. The photomask blank according to Configuration 3, wherein the photomask blank is made of a material mainly containing any one of chromium nitride, chromium oxide, chromium nitride oxide, and chromium oxycarbonitride.
(Configuration 5)
The photomask blank according to any one of Structures 1 to 4, wherein the low reflective layer is made of a molybdenum silicide compound containing at least one of oxygen and nitrogen.
(Configuration 6)
A photomask blank for producing a phase shift mask provided with a phase shift portion for generating a predetermined phase difference with respect to exposure light transmitted through a light transmissive substrate,
The phase shift unit is dug from the surface of the translucent substrate with a dug depth that causes a predetermined phase difference with respect to the exposure light that passes through the part of the translucent substrate that is not provided with the phase shift unit. A dug,
The low reflective layer is made of a material having an etching selectivity with respect to an etching gas used when digging a translucent substrate by dry etching, and is formed in contact with the surface on the side of digging the translucent substrate. The photomask blank according to any one of Configurations 1 to 4, wherein:
(Configuration 7)
A photomask blank for producing a phase shift mask provided with a phase shift portion for generating a predetermined phase difference with respect to exposure light transmitted through a light transmissive substrate,
The phase shift unit is a phase shift film that gives a predetermined amount of phase change to transmitted exposure light,
The low reflection layer is made of a material having etching selectivity with respect to an etching gas used when dry-etching the phase shift film, and is formed in contact with the surface of the phase shift film. The photomask blank according to any one of 1 to 4.
(Configuration 8)
The low reflective layer is
Any one of Structures 6 and 7 formed of a material mainly containing any one of chromium, chromium nitride, chromium oxide, chromium nitride oxide, chromium oxycarbonitride, tantalum-hafnium, and tantalum-zirconium. The photomask blank described in 1.
(Configuration 9)
A photomask manufactured using the photomask blank according to any one of Configurations 1 to 8.
(Configuration 10)
A photomask manufacturing method using the photomask blank according to any one of Configurations 1 to 8.

ADVANTAGE OF THE INVENTION According to this invention, the photomask blank and photomask which have the practical quality of the generation aiming at resist film thickness 200nm or less and also resist film thickness 150nm or less can be provided.
Also according to the present invention, DRAM half pitch (hp) 4 in the semiconductor design rule.
It is possible to provide a photomask blank and a photomask that can achieve the thinning of the main light-shielding film (and hence the thinning of the transfer pattern) that can cope with the ultra-high NA technology and double patterning required for the generations after 5 nm, especially the hp32-22 nm generation .
Furthermore, according to the present invention, it is possible to provide a photomask blank and a photomask that can achieve a pattern resolution of 50 nm or less on the mask.

Hereinafter, the present invention will be described in detail.
The photomask blank of the present invention comprises a light-shielding film on a light-transmitting substrate used for producing a photomask for ArF excimer laser exposure, and the light-shielding film has a molybdenum content of 20 atomic%. Made of molybdenum silicide metal that is 40 atomic% or less,
A light shielding layer having a thickness of less than 40 nm, an antireflection layer formed on and in contact with the light shielding layer and made of a molybdenum silicide compound containing at least one of oxygen and nitrogen, and under the light shielding layer It is characterized by comprising a low reflection layer to be formed (Configuration 1).

The inventor of the present invention has a light shielding layer made of molybdenum silicide metal having a molybdenum content of more than 20 atomic% and not more than 40 atomic%, as shown in FIG. 14, having a composition outside this range (the molybdenum content is 20 atomic%). (Below 40 atomic%), a light shielding layer having a relatively large light shielding property in ArF excimer laser exposure light can be obtained, and the thickness of the light shielding layer is less than 40 nm. A predetermined light-shielding property (optical density) can be obtained, and by combining with a light-shielding antireflection layer and a low-reflective layer equivalent to conventional ones, a sufficient light-shielding property can be obtained as a light shielding film for an ArF excimer laser exposure photomask. To be found, composition 1
The present invention has been completed.
According to the first aspect of the invention, the following operational effects can be obtained.
(1) The following effects can be obtained by reducing the thickness of the light shielding film (thinning the transfer pattern).
1) Prevents mask pattern collapse during mask cleaning.
2) Since the side wall height of the mask pattern is reduced by reducing the thickness of the light shielding film, the pattern accuracy particularly in the side wall height direction can be improved and the CD accuracy (particularly linearity) can be increased.
3) Especially for photomasks used in the high NA (immersion) generation, it is necessary to make the mask pattern thin (to reduce the side wall height of the mask pattern) as a countermeasure against shadowing, but this requirement is met .
(2) When the Mo content of the light shielding layer is within the range of the present invention, the following effects are obtained.
1) The etching rate in dry etching with a fluorine-based gas is relatively higher than the composition outside the range of the present invention.

In the present invention, the light shielding layer made of molybdenum silicide metal refers to a light shielding layer (a metallic film substantially free of oxygen, nitrogen, etc.) substantially composed of molybdenum and silicon. This substantially free of oxygen and nitrogen is within a range where the effects of the present invention can be obtained (
Oxygen and nitrogen are both contained in less than 5 at% of each component in the light shielding layer. From the viewpoint of light shielding performance, it is preferably not originally contained in the light shielding layer. However, since it is often mixed as an impurity in the stage of the film formation process, the photomask manufacturing process, etc., it is allowed within a range that does not substantially affect the light shielding performance.
Further, in the present invention, the light shielding layer made of molybdenum silicide metal has the above characteristics,
Other elements (carbon, helium, hydrogen, argon, xenon, etc.) may be included as long as the effects are not impaired.
In the present invention, the light-shielding layer preferably has a layer thickness of 30 nm to less than 40 nm, and more preferably 33 nm to 38 nm.

The photomask blank of the present invention is
The antireflection layer contains more than 0 atomic% and 10 atomic% or less of molybdenum (Configuration 2).

The inventor combined a light-shielding layer having a relatively high Mo content with an antireflection layer having a relatively low Mo content, thereby providing a light-shielding film layer that satisfies both optical properties and chemical resistance. It was found that the configuration could be made, and the invention according to Configuration 2 was completed.
According to the invention according to Configuration 2, the following operational effects can be obtained.
(1) When the Mo content of the antireflection layer is within the range of the present invention, the following effects are obtained.
1) It is relatively excellent in chemical resistance (cleaning resistance) of the antireflection layer relative to a composition outside the range of the present invention.
2) Relatively excellent heat resistance of the antireflection layer relative to the composition outside the range of the present invention. Specifically, the antireflection layer according to Configuration 2 does not cause white turbidity due to heat treatment, and does not deteriorate the surface reflectance distribution.

In the present invention, the antireflection layer made of a molybdenum silicide compound containing at least one of oxygen and nitrogen is composed of MoSiON, MoSiO, MoSiN, MoSiOC, Mo
Examples thereof include SiOCN. Among these, from the viewpoint of chemical resistance and heat resistance, MoSi
O and MoSiON are preferable, and MoSiON is preferable from the viewpoint of blanks defect quality.

In the present invention, the antireflection layer, MoSiON, MoSiO, MoSiN, MoSi
In the case of OC, MoSiOCN, etc., if the amount of Mo is increased, the cleaning resistance, in particular, the resistance to alkali (ammonia water, etc.) and warm water decreases. From this point of view, MoSiON which is an antireflection layer,
For MoSiO, MoSiN, MoSiOC, MoSiOCN, etc., it is preferable to reduce Mo as much as possible.
Further, it was found that when heat treatment (annealing) was performed at a high temperature for the purpose of stress control, a high Mo content causes a phenomenon that the surface of the film becomes clouded white (clouded). This is considered to be because MoO precipitates on the surface. From the viewpoint of avoiding such a phenomenon, the Mo content in the antireflection layer is preferably less than 10 at% in MoSiON, MoSiO, MoSiN, MoSiOC, MoSiOCN, and the like that are antireflection layers. However, when the Mo content is too low, abnormal discharge during DC sputtering becomes significant, and the frequency of occurrence of defects increases. Therefore, it is desirable that Mo is contained within a range where it can be sputtered normally. Depending on other film formation techniques, film formation may be possible without containing Mo.
In the present invention, the antireflection layer preferably has a thickness of 5 nm to 15 nm, and more preferably 8 nm to 12 nm.

In the present invention, the MoSi light-shielding layer can freely control tensile stress and compressive stress by Ar gas pressure, He gas pressure, and heat treatment. For example, by controlling the film stress of the MoSi light shielding layer to be a tensile stress, it is possible to match the compressive stress of the antireflection layer (for example, MoSiON). That is, the stress of each layer constituting the light shielding film can be offset, and the film stress of the light shielding film can be reduced as much as possible (can be substantially zero).
On the other hand, when the light shielding layer is MoSiN, the film stress of MoSiN is on the compression side, and it is difficult to adjust the stress of the light shielding layer. For this reason, it is difficult to match the compressive stress of the antireflection layer (for example, MoSiON).

In the present invention, it is preferable to include an etching mask layer made of a material mainly composed of chromium, which is a film formed on and in contact with the light shielding film (Configuration 3).
This is for reducing the thickness of the resist.

In the present invention, it is preferable that the etching mask film is formed of a material mainly composed of any one of chromium nitride, chromium oxide, chromium nitride oxide, and chromium oxycarbonitride (Configuration 4).
This is because the etching selectivity to the antireflection layer and the light shielding layer made of molybdenum silicide compound formed under the etching mask film is high and the unnecessary etching mask film can be removed without damaging other layers. is there.
In the present invention, the etching mask film is, for example, chromium alone, oxygen in chromium,
A material such as one containing at least one element composed of nitrogen, carbon, and hydrogen (a material containing Cr) can be used. The film structure of the etching mask film is often a single layer made of the above film material, but may be a multi-layer structure. In addition, the multi-layer structure can be a multi-layer structure formed in stages with different compositions or a film structure in which the composition is continuously changed.
Among the above, the material of the etching mask layer is chromium oxycarbonitride (CrOC).
N) is preferable from the viewpoint of controllability of stress (a low stress film can be formed).
In the present invention, the etching mask film preferably has a thickness of 5 nm to 30 nm.

In the present invention, the low reflection film comprises a low reflection layer (back surface antireflection layer) which is a layer made of a molybdenum silicide compound containing at least one of oxygen and nitrogen (Configuration 5).
With such a configuration, it is possible to prevent reflection on the back side (translucent substrate side) of the light-shielding film.
Note that when the low reflection layer and the light shielding layer are produced using a target having the same Mo and Si content ratio, not only the production is easy and the cost is reduced, but also the Mo and S in the low reflection layer and the light shielding layer.
Since the content ratio with i is the same and the etching rates of these layers are also the same, it is preferable from the viewpoint of improving accuracy in the pattern side wall (cross-sectional) direction of the light shielding film.

In the present invention, a photomask blank for producing a phase shift mask provided with a phase shift portion for generating a predetermined phase difference with respect to the transmitted exposure light on the light transmissive substrate,
The phase shift unit is dug from the surface of the translucent substrate with a dug depth that causes a predetermined phase difference with respect to the exposure light that passes through the part of the translucent substrate that is not provided with the phase shift unit. A dug,
The low reflective layer is made of a material having an etching selectivity with respect to an etching gas used when digging a translucent substrate by dry etching, and is formed in contact with a surface on the side of digging the translucent substrate. It is preferable (Configuration 6).
An etching mask for digging a translucent substrate by forming the low reflective layer with a material having etching selectivity with respect to an etching gas such as a fluorine-based gas used when dry-etching the translucent substrate. Can also function.
Thereby, the processing accuracy of the phase shift part formed by digging the substrate can be improved.
According to the configuration 6, it is possible to provide a photomask blank having a substrate shift type phase shift portion having a practical quality of a generation aiming at a resist film thickness of 200 nm or less, and further a resist film thickness of 150 nm or less.

In the present invention, a photomask blank for producing a phase shift mask provided with a phase shift portion for generating a predetermined phase difference with respect to the transmitted exposure light on the light transmissive substrate,
The phase shift unit is a phase shift film that gives a predetermined amount of phase change to transmitted exposure light, and the low reflection layer is etched with respect to an etching gas used when dry-etching the phase shift film. It is preferably made of a material having selectivity and formed in contact with the surface of the phase shift film (Configuration 7).
An etching mask for digging a translucent substrate by forming the low reflective layer with a material having etching selectivity with respect to an etching gas such as a fluorine-based gas used when dry-etching the translucent substrate. Can also function.
Thereby, the processing accuracy of the phase shift part formed by digging the substrate can be improved.
A phase shift formed by processing the phase shift film by forming the low reflection layer with a material having etching selectivity with respect to an etching gas such as a fluorine-based gas used when dry-etching the phase shift film. This is to improve the machining accuracy of the part.
According to the configuration 7, a photomask blank having a phase shift portion formed by processing a phase shift film and having a practical quality of a generation aiming at a resist film thickness of 200 nm or less, and further a resist film thickness of 150 nm or less. Can provide.

In the present invention, the phase shift film is formed of a material mainly composed of molybdenum silicide, molybdenum silicide nitride, molybdenum silicide oxide, molybdenum silicide nitride oxide, or molybdenum silicide nitrided oxide carbide. It can be set as the aspect which is.
According to such a configuration, for example, a halftone phase shift mask having a transmittance of about 2% to 20% for a wavelength of 193 nm of ArF excimer laser exposure light can be obtained.

In the present invention, the phase shift film may be formed by laminating a phase adjustment layer and a transmittance adjustment layer.
According to such a configuration, for example, it is possible to obtain a high transmittance type halftone phase shift mask without digging the substrate.
Here, as the material of the transmittance adjusting layer, a film made of one or two or more kinds selected from metal and silicon, or oxides, nitrides, oxynitrides, carbides and the like thereof can be used. Specifically, a film made of one or more materials selected from aluminum, titanium, vanadium, chromium, zirconium, niobium, molybdenum, lanthanum, tantalum, tungsten, silicon, and hafnium, or nitrides, oxides thereof, Examples thereof include oxynitrides and carbides. Further, as the phase adjustment layer, a thin film based on silicon such as silicon oxide, silicon nitride, or silicon oxynitride is preferable because a relatively high transmittance can be easily obtained with respect to exposure light in the ultraviolet region.
In the present invention, the phase shift film includes, for example, a phase adjustment layer formed of a material mainly composed of silicon oxide or silicon oxynitride, and a transmittance adjustment layer mainly composed of tantalum or a tantalum-hafnium alloy. It can be set as the aspect which consists of.

In the present invention, the low reflection layer may be formed of a material mainly containing any one of chromium, chromium nitride, chromium oxide, chromium nitride oxide, chromium oxycarbonitride, tantalum-hafnium, and tantalum-zirconium. Preferred (Configuration 8).
This is because the processing accuracy is excellent. Further, the etching selectivity with respect to the layer formed in contact with the upper and lower sides of the low reflection layer is high, and the etching mask film which becomes unnecessary can be removed without damaging other layers.
In the present invention, for the low reflection layer, for example, a material such as chromium alone or a material containing at least one element composed of oxygen, nitrogen, carbon, and hydrogen in chromium (a material containing Cr) can be used. . The film structure of the second etching mask layer is often a single layer made of the above film material, but may be a multi-layer structure. In addition, the multi-layer structure can be a multi-layer structure formed in stages with different compositions or a film structure in which the composition is continuously changed.
The low reflective layer can also be made of a material mainly composed of tantalum-hafnium or tantalum-zirconium. These materials are materials that are dry-etched with a chlorine-based gas that does not substantially contain oxygen, but are not substantially dry-etched with a fluorine-based gas, and are anti-reflection layers and light-shielding layers that are dry-etched with a fluorine-based gas. Etching selectivity with respect to translucent substrate.
Among the above, chromium oxycarbonitride (CrOCN) is particularly preferable as a material for the low reflection layer from the viewpoint of stress control. In addition, chromium nitride (CrN) is also preferable from the viewpoint that the film stress can be easily offset between the upper light shielding layer and the antireflection layer. Furthermore, in the case of a photomask blank having a phase shift film, the function as an etching mask (etching selectivity) is particularly important rather than the antireflection function. From this viewpoint, chromium nitride (C
rN) is particularly preferred.
In the present invention, the low reflection layer preferably has a thickness of 10 nm to 30 nm.

The photomask of the present invention is produced using the photomask blank according to the present invention (Configuration 9).
Thereby, the effect similar to having described to the said structures 1-8 is acquired.

The method for producing a photomask of the present invention uses the photomask blank according to the present invention (Configuration 10).
Thereby, the effect similar to having described to the said structures 1-8 is acquired.

In the present invention, it is preferable to use a dry etching gas composed of a chlorine-based gas or a mixed gas containing a chlorine-based gas and an oxygen gas for the dry etching of the chromium-based thin film.
The reason for this is that for a chromium-based thin film made of a material containing chromium and an element such as oxygen and nitrogen, the dry etching rate can be increased by performing dry etching using the above dry etching gas, This is because the dry etching time can be shortened and a light-shielding film pattern having a good cross-sectional shape can be formed. The chlorine-based gas used for dry etching gas, for _{example, Cl 2, SiCl 4, HCl} , CCl 4, CHC
l ₃ etc. are mentioned.

In the present invention, for example, fluorine-based gas such as SF ₆ , CF ₄ , C ₂ F ₆ , and CHF ₃ is used for the etching of the substrate, the dry etching of the silicon-containing film containing silicon, and the metal silicide-based thin film. , These and a mixed gas such as He, H ₂ , N ₂ , Ar, C ₂ H ₄ , O ₂ , or Cl ₂ ,
A chlorine-based gas such as CH ₂ Cl ₂ or a mixed gas of these with He, H ₂ , N ₂ , Ar, C ₂ H ₄ or the like can be used.

In the present invention, examples of the substrate include a synthetic quartz substrate, a CaF ₂ substrate, a soda lime glass substrate, a non-alkali glass substrate, a low thermal expansion glass substrate, and an aluminosilicate glass substrate.

In the present invention, the photomask blank includes an imprint mask blank and the like in addition to the binary photomask blank and the phase shift mask blank that do not use the phase shift effect. In addition, the photomask blank includes a mask blank with a resist film,
Is also included.
In the present invention, the photomask includes a binary photomask and a phase shift mask that do not use the phase shift effect. The photomask includes a reticle. The phase shift mask includes a case where the phase shifter is formed by excavating the substrate.

Examples of the present invention and comparative examples are shown below. In addition, each film | membrane, such as a light shielding film in each Example and a comparative example, an etching film, and a phase shift film, was formed by sputtering method as a film-forming method, and was formed into a film using DC magnetron sputtering apparatus as a sputtering device. However, in carrying out the present invention, the film forming method and the film forming apparatus are not particularly limited, and other types of sputtering apparatuses such as an RF magnetron sputtering apparatus may be used.
Example 1
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the translucent substrate 1, and a MoSiON film 11 (low reflection layer) and MoSi (light shielding layer) are formed on the translucent substrate 1 as the light shielding film 10. Layer) 12 and a MoSiON film (antireflection layer) 13 were formed (FIG. 1).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar, O ₂ and N
₂ and He sputtering gas pressure 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : He = 5
: 4: 49: 42), the power of the DC power source is 3.0 kW, and the film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic percent ratio of Mo to Si in the film is about 21:79) 7
Next, using the same target, Ar is formed with a sputtering gas pressure of 0. nm.
1 Pa, DC power is 2.0 kW, and a film made of molybdenum and silicon (Mo
Si film: Atomic ratio of Mo and Si in the film is about 21:79) is formed with a film thickness of 35 nm, and then a target of Mo: Si = 4: 96 (atomic% ratio) is used. ₂ and _{N 2} and He sputtering gas pressure of 0.2 Pa (gas flow ratio _{Ar: O 2: N 2:} He = 5: 4: 49
: 42), the power of the DC power source is 3.0 kW, and the film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic% ratio of Mo to Si in the film is about 4:96) is 10 nm thick. Formed with. The total film thickness of the light-shielding film 10 was 52 nm. Optical density (OD) of the light-shielding film 10
) Was 3 at a wavelength of 193 nm of ArF excimer laser exposure light.
Next, the substrate was heated (annealed) at 400 ° C. for 30 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 1). Specifically, a chromium target is used, and Ar, CO ₂ , N _2, and He are mixed with a sputtering gas pressure of 0.2 Pa.
(Gas flow ratio Ar: CO ₂ : N ₂ : He = 21: 37: 11: 31), the power of the DC power source was 1.8 kW, and CrOCN was formed to a thickness of 15 nm. At this time, the CrOCN film is changed to the M
By annealing at a temperature lower than the annealing temperature of the oSi light shielding film, the stress of the CrOCN film was adjusted to be as low as possible (preferably substantially zero film stress) without affecting the film stress of the MoSi light shielding film.
As described above, a photomask blank having a light shielding film for ArF excimer laser exposure was obtained.
(Production of photomask)
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 for electron beam drawing (exposure) (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 1, Fig. 5 (1))
.
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 50a (FIG. 5 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 5 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the light shielding film 10 was dry-etched using a mixed gas of SF ₆ and He to form the light shielding film pattern 10a (FIG. 5D).
Next, the etching mask film pattern 20a is peeled off by dry etching with a mixed gas of Cl ₂ and O ₂ (FIG. 5 (5)), and is subjected to a predetermined cleaning, thereby performing photomask 10
0 was obtained.
In this photomask manufacturing example, after the etching mask film pattern 20a is formed, the resist pattern 50a is peeled and removed. This is because the mask pattern of the mask pattern is formed when the light shielding film pattern 10a is formed on the light shielding film 10 in the next process. This is because the lower the side wall height (= the side wall height of the etching mask film pattern 20a), the higher the CD accuracy, the smaller the microloading, and the higher the processing accuracy. In the case where a photomask that does not require processing accuracy up to that point is manufactured, or in the case where it is desired that the etching mask film also has a role of preventing reflection of exposure light, the resist pattern 50a is formed after the light shielding film pattern 10a is formed. You may make it peel and remove.

(Reference Example 1)
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the light-transmitting substrate 1, and a MoSiON film 11 (low reflection layer), a MoSi film (as a light-shielding film 10) are formed on the light-transmitting substrate 1.
A light shielding layer 12 and a MoSiON film (antireflection layer) 13 were formed (FIG. 10).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar, O ₂ and N
₂ and He sputtering gas pressure 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : He = 5
: 4: 49: 42), the power of the DC power source is 3.0 kW, and the film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic percent ratio of Mo to Si in the film is about 21:79) 7
Next, using the same target, Ar is formed with a sputtering gas pressure of 0. nm.
1 Pa, DC power is 2.0 kW, and a film made of molybdenum and silicon (Mo
(Si film: Mo: Si atomic% ratio in the film is about 21:79) is formed with a film thickness of 35 nm, and then using the same target, Ar, O ₂ , N ₂ and He are sputtered at a sputtering gas pressure of 0. 2Pa
(Gas flow ratio Ar: O ₂ : N ₂ : He = 5: 4: 49: 42), the power of the DC power source is 3.0 kW, and a film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: in the film) The atomic percent ratio of Mo to Si was about 21:79) with a film thickness of 10 nm. The total film thickness of the light-shielding film 10 was 52 nm. The optical density (OD) of the light-shielding film 10 was 3 at a wavelength of 193 nm of ArF excimer laser exposure light.
Next, the substrate was heated (annealed) at 400 ° C. for 30 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 10). In particular,
A chromium target was used, N ₂ was formed at a sputtering gas pressure of 0.2 Pa, DC power was 1.8 kW, and CrN was formed to a thickness of 15 nm.
As described above, a photomask blank having a light shielding film for ArF excimer laser exposure was obtained.
Incidentally, in Reference Example 1 shown in FIG. 10, the atomic% ratio of Mo and Si in the MoSiON film (antireflection layer) 13 is changed from about 4:96 to 21:79 in Example 1 shown in FIG. The same as in Example 1 except that the etching mask film 20 is changed from CrOCN to CrN.
(Production of photomask)
FIG. 5 used in the description of the first embodiment will be used instead.
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 for electron beam drawing (exposure) (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 9, Fig. 5 (1))
.
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 50a (FIG. 5 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 5 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the light shielding film 10 is formed of SF ₆ and H
Using a mixed gas of e, dry etching was performed to form a light shielding film pattern 10a (FIG. 5).
(4)).
Next, the etching mask film pattern 20a is peeled off by dry etching with a mixed gas of Cl ₂ and O ₂ (FIG. 5 (5)), and is subjected to a predetermined cleaning, thereby performing photomask 10
0 was obtained.

(Comparative Example 1)
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the light-transmitting substrate 1, and a MoSiON film 11 (low reflection layer), a MoSi film (as a light-shielding film 10) are formed on the light-transmitting substrate 1.
A light shielding layer 12 and a MoSiON film (antireflection layer) 13 were formed (FIG. 12).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar, O ₂ and N
₂ and He sputtering gas pressure 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : He = 5
: 4: 49: 42), the power of the DC power source is 3.0 kW, and the film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic percent ratio of Mo to Si in the film is about 21:79) 7
Next, using a target of Mo: Si = 10: 90 (atomic% ratio), Ar with a sputtering gas pressure of 0.2 Pa, DC power supply of 2.0 kW, molybdenum and silicon (MoSi film: atomic percentage ratio of Mo and Si in the film is 10:90)
Then, using the same target, Ar, O ₂ and N ₂ : He were sputtered with a gas pressure of 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : He = 5: 4: 49
: 42), the power of the DC power source is 3.0 kW, and a film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic percentage ratio of Mo to Si in the film is 10:90) is 10 nm thick. Formed. The total film thickness of the light-shielding film 10 was 61 nm. Optical density (OD) of the light-shielding film 10
) Was 3 at a wavelength of 193 nm of ArF excimer laser exposure light.
Next, the substrate was heated (annealed) at 400 ° C. for 30 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 12). In particular,
A chromium target was used, N ₂ was formed at a sputtering gas pressure of 0.2 Pa, DC power was 1.8 kW, and CrN was formed to a thickness of 15 nm.
As described above, a photomask blank having a light-shielding film for ArF excimer laser exposure was obtained.
Incidentally, in Comparative Example 1 shown in FIG. 12, the atomic% ratio of Mo and Si in each film of the MoSiON film (antireflection film) 13 and the light shielding layer 12 in Example 1 shown in FIG. 10:90
In addition, it is the same as in Example 1 except that the etching mask film 20 is changed from CrOCN to CrN.
(Production of photomask)
FIG. 5 used in the description of the first embodiment will be used instead.
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) for electron beam drawing (exposure) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 12, Fig. 5 (1)
).
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 50a (FIG. 5 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 5 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the light shielding film 10 was dry-etched using a mixed gas of SF ₆ and He to form the light shielding film pattern 10a (FIG. 5D).
Next, the etching mask film pattern 20a is peeled off by dry etching with a mixed gas of Cl ₂ and O ₂ (FIG. 5 (5)), and is subjected to a predetermined cleaning, thereby performing photomask 10
0 was obtained.

(Example 2)
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the light-transmitting substrate 1, and the Cr is a low-reflection layer of the light-shielding film 10 on the light-transmitting substrate 1 and also functions as an etching mask.
An N film 30 was formed (FIG. 2). Specifically, a chromium target is used, Ar and N ₂ are set to a sputtering gas pressure of 0.1 Pa (gas flow ratio Ar: N ₂ = 4: 1), the power of the DC power source is 1.3 kW, and CrN is 20 nm. The film thickness was formed.
Next, a MoSi film (light-shielding layer) 1 is formed on the CrN film (low-reflection layer) 30 as the light-shielding film 10.
2. A MoSiON film (antireflection layer) 13 was formed (FIG. 2).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar is set to a sputtering gas pressure of 0.1 Pa, the power of the DC power source is 2.0 kW, and a film made of molybdenum and silicon (MoSi film: An atomic% ratio of Mo to Si in the film is about 21:79) with a film thickness of 25 nm, and then using a target of Mo: Si = 4: 96 (atomic% ratio), Ar and O
₂ and N ₂ and He are sputtered at a gas pressure of 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : H
e = 5: 4: 49: 42), the power of the DC power source is 3.0 kW, and a film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic% ratio of Mo to Si in the film is about 4: 96)
Was formed with a film thickness of 10 nm. The total film thickness of the light shielding film 10 was 55 nm.
Next, the substrate was heated (annealed) at 250 ° C. for 5 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 2). Specifically, a chromium target is used, CO ₂ and N ₂ are set to a sputtering gas pressure of 0.2 Pa (gas flow ratio CO ₂ : N ₂ = 7: 2), the power of the DC power source is 1.8 kW, and CrOCN 18nm
The film thickness was formed. At this time, the film stress of the CrOCN film was adjusted to be as low as possible (preferably substantially zero film stress).
The optical density (OD) of the light-shielding film 10 was 3 at a wavelength of 193 nm for ArF excimer laser exposure.
As described above, a photomask blank having a light-shielding film for ArF excimer laser exposure was obtained.
(Production of photomask)
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) for electron beam drawing (exposure) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 2, Fig. 6 (1))
.
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and developed with a predetermined developer to form a resist pattern 50a (FIG. 6 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 6 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the MoSi film (light shielding layer) 1
2 and the MoSiON film (antireflection layer) 13 were dry-etched using a mixed gas of SF ₆ and He to form film patterns 12a and 13a (FIG. 6 (4)).
Next, using the film patterns 12a and 13a as a mask, the CrN film (low reflection layer) 30 was dry-etched to form a film pattern 30a. At the same time, the etching mask film pattern 20a made of CrOCN is also removed by etching (FIG. 6 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, again, a chemical amplification type positive resist 51 for electron beam drawing (exposure) (FEP171: manufactured by Fuji Film Electronics Materials) has a film thickness of 300 n by spin coating.
It applied so that it might become m (FIG. 6 (6)).
Next, a desired pattern was drawn on the resist film 51 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 51a (FIG. 6 (7)). Here, the resist pattern 51a is formed for the purpose of forming a light-shielding band in the outer peripheral region of the substrate, a large-area light-shielding portion patch, and a zebra pattern for performing transmittance control.
Next, using the resist pattern 51a as a mask, the film patterns 12a and 13a were removed by dry etching (FIG. 6 (8)). At this time, as a dry etching gas, a mixed gas of SF ₆ and He that can obtain a selection ratio between the film patterns 12a and 13a mainly composed of molybdenum silicide and the translucent substrate 1 was used.
Next, using the resist pattern 51a and the film pattern 30a as a mask, the translucent substrate 1 is
Dry etching was performed using a mixed gas of CHF ₃ and He to form a substrate excavation type phase shift pattern (FIG. 6 (9)). At this time, the substrate was dug to a depth (about 170 nm) at which a phase difference of 180 ° was obtained.
Next, using the resist pattern 51a as a mask, the film pattern 30a was peeled off by dry etching (FIG. 6 (10)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the thin resist pattern 51a was peeled off (FIG. 6 (11)), and predetermined cleaning was performed to obtain a photomask 100.
In this photomask manufacturing example, the etching mask film pattern 20a is completely removed. However, the etching mask film pattern 20a is used together with the antireflection layer 13 of the light shielding film 10 or the etching mask film pattern 20a alone to prevent reflection of exposure light. In the case where it is desired to leave the corresponding part in the photomask in order to have a role, after forming the etching mask film pattern 20a (between the processes of FIGS. 6 (3) and (4)), the resist pattern 50a is changed. The film pattern 30a may be formed in a state where it is not peeled off. However, in this case, after forming the resist pattern 51a, the etching mask film pattern 20a other than the portion protected by the resist pattern 51a by dry etching with a mixed gas of chlorine and oxygen.
Need to be added (between the processes shown in FIGS. 6 (7) and (8)).

(Reference Example 2)
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the light-transmitting substrate 1, and the Cr is a low-reflection layer of the light-shielding film 10 on the light-transmitting substrate 1 and also functions as an etching mask.
An N film 30 was formed (FIG. 11). Specifically, a chromium target is used, Ar and N ₂ are used as sputtering gases (gas flow ratio Ar: N ₂ = 4: 1), and the power of the DC power source is 1.3.
CrN was formed to a thickness of 20 nm at kW.
Next, a MoSi film (light-shielding layer) 1 is formed on the CrN film (low-reflection layer) 30 as the light-shielding film 10.
2. A MoSiON film (antireflection layer) 13 was formed (FIG. 11).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar is set to a sputtering gas pressure of 0.1 Pa, the power of the DC power source is 2.0 kW, and a film made of molybdenum and silicon (MoSi film: The atomic% ratio of Mo to Si in the film is about 21:79) and is formed with a film thickness of 25 nm. Then, using the same target, Ar, O ₂ , N ₂ and He are sputtered at a gas pressure of 0.2 Pa (gas Flow rate ratio Ar: O ₂ : N ₂ : He = 5: 4: 49: 42)
The power of the DC power source is 3.0 kW and a film made of molybdenum, silicon, oxygen and nitrogen (MoS
iON film: The atomic% ratio of Mo and Si in the film was about 21:79) with a film thickness of 10 nm.
The total film thickness of the light shielding film 10 was 55 nm.
Next, the substrate was heated (annealed) at 250 ° C. for 5 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 11). In particular,
A chromium target was used, N ₂ was formed at a sputtering gas pressure of 0.2 Pa, DC power was 1.8 kW, and CrN was formed to a thickness of 18 nm.
The optical density (OD) of the laminated film of the light-shielding film 10 is the wavelength 1 of ArF excimer laser exposure light.
3 at 93 nm.
As described above, a photomask blank having a light-shielding film for ArF excimer laser exposure was obtained.
In Reference Example 2 shown in FIG. 11, the atomic% ratio of Mo and Si in the MoSiON film (antireflection film) 13 is changed from about 4:96 to 21:79 in Example 2 shown in FIG. The etching mask film 20 is the same as that of Example 2 except that the etching mask film 20 is changed from CrOCN to CrN.
(Production of photomask)
A description will be given by substituting FIG. 6 used in the description of the second embodiment.
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) for electron beam drawing (exposure) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 11, Fig. 6 (1)
).
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and developed with a predetermined developer to form a resist pattern 50a (FIG. 6 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 6 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the MoSi film (light shielding layer) 1
2 and the MoSiON film (antireflection layer) 13 were dry-etched using a mixed gas of SF ₆ and He to form film patterns 12a and 13a (FIG. 6 (4)).
Next, using the film patterns 12a and 13a as a mask, the CrN film (low reflection layer) 30 was dry-etched to form a film pattern 30a. At this time, the etching mask film pattern 20a made of CrN is also removed by etching (FIG. 6 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, again, a chemical amplification type positive resist 51 for electron beam drawing (exposure) (FEP171: manufactured by Fuji Film Electronics Materials) has a film thickness of 300 n by spin coating.
It applied so that it might become m (FIG. 6 (6)).
Next, a desired pattern was drawn on the resist film 51 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 51a (FIG. 6 (7)). Here, the resist pattern 51a is formed for the purpose of forming a light-shielding band in the outer peripheral region of the substrate, a large-area light-shielding portion patch, and a zebra pattern for performing transmittance control.
Next, using the resist pattern 51a as a mask, the film patterns 12a and 13a were removed by dry etching (FIG. 6 (8)). At this time, as a dry etching gas, a mixed gas of SF ₆ and He that can obtain a selection ratio between the film patterns 12a and 13a mainly composed of molybdenum silicide and the translucent substrate 1 was used.
Next, using the resist pattern 51a as a mask, the translucent substrate 1 was dry-etched using a mixed gas of CHF ₃ and He to form a substrate excavation type phase shift pattern (FIG. 6 (9)). . At this time, the substrate was dug to a depth (about 170 nm) at which a phase difference of 180 ° was obtained.
Next, using the resist pattern 51a as a mask, the film pattern 30a was peeled off by dry etching (FIG. 6 (10)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the thin resist pattern 51a was peeled off (FIG. 6 (11)), and predetermined cleaning was performed to obtain a photomask 100.

(Example 3)
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches was used as the light transmitting substrate 1, and a MoSiN halftone phase shift film 40 was formed on the light transmitting substrate 1. Specifically, using a target of Mo: Si = 10: 90 (atomic% ratio), argon (Ar) and nitrogen (
N ₂ ) is a sputtering gas pressure of 0.2 Pa (gas flow rate ratio Ar: N ₂ = 10: 90), the power of the DC power source is 3.0 kW, and the film thickness is 69 [nm] and is MoSiN-based semi-translucent. A phase shift film 40 was formed (FIG. 3). At this time, the thickness of the halftone phase shift film 40 was set such that a phase difference of 180 ° was obtained with respect to the exposure wavelength of 193 nm. The transmittance of the halftone phase shift film 40 was 6% with respect to the exposure wavelength of 193 nm.
Next, a CrN film (low reflection layer) 30 was formed on the halftone phase shift film 40 (FIG. 3).
). Specifically, a chromium target is used, Ar and N ₂ are used as sputtering gases (gas flow ratio Ar: N ₂ = 4: 1), DC power is 1.3 kW, and CrN is 15 nm thick. Formed.
Next, a MoSi film (light shielding layer) 12 and MoSi are formed on the CrN film 30 as the light shielding film 10.
An ON film (antireflection layer) 13 was formed (FIG. 3).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar is set to a sputtering gas pressure of 0.1 Pa, the power of the DC power source is 2.0 kW, and a film made of molybdenum and silicon (MoSi film: An atomic% ratio of Mo to Si in the film is about 21:79) with a film thickness of 11 nm, and then using a target of Mo: Si = 4: 96 (atomic% ratio), Ar and O
₂ and N ₂ : He sputtering gas pressure 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : H
e = 5: 4: 49: 42), the power of the DC power source is 3.0 kW, and a film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic% ratio of Mo to Si in the film is about 4: 96)
Was formed with a film thickness of 10 nm. The total film thickness of the light shielding film 10 was 36 nm.
Next, the substrate was heated (annealed) at 250 ° C. for 5 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 3). Specifically, a chromium target is used, and CO ₂ and N ₂ are sputtered (gas flow ratio CO ₂ : N
₂ = 7: 2), the power of the DC power source was 1.8 kW, and CrOCN was formed to a thickness of 15 nm. At this time, the film stress of the CrOCN film was adjusted to be as low as possible (preferably substantially zero film stress).
The optical density (OD) of the laminated film of the halftone phase shift film 40 and the light shielding film 10 is Ar.
The value was 3 at a wavelength of 193 nm of the F excimer laser exposure light.
As described above, a photomask blank having a light-shielding film for ArF excimer laser exposure was obtained.
(Production of photomask)
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 for electron beam drawing (exposure) (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 3, Fig. 7 (1))
.
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 50a (FIG. 7 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 7 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the MoSi film (light shielding layer) 1
2 and the MoSiON film (antireflection layer) 13 were dry-etched using a mixed gas of SF ₆ and He to form film patterns 12a and 13a (FIG. 7 (4)).
Next, using the film patterns 12a and 13a as a mask, the CrN film (low reflection layer) 30 was dry-etched to form a film pattern 30a. At the same time, the etching mask film pattern 20a made of CrOCN is also removed by etching (FIG. 7 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, again, a chemical amplification type positive resist 51 for electron beam drawing (exposure) (FEP171: manufactured by Fuji Film Electronics Materials) has a film thickness of 300 n by spin coating.
It applied so that it might become m (FIG. 7 (6)).
Next, after drawing a desired pattern on the resist film 51 using an electron beam drawing apparatus, the resist film 51 was developed with a predetermined developer to form a resist pattern 51a (FIG. 7 (7)). Here, the resist pattern 51a is formed for the purpose of forming a light shielding band in the outer peripheral region of the substrate.
Next, using the film pattern 30a as a mask, the halftone phase shift film 40 is made of SF ₆
A half-tone phase shift film pattern 40a was formed by dry etching using a mixed gas of He and He. At this time, a film pattern 1 made of MoSi and MoSiON simultaneously.
2a and 13a are removed by etching (FIG. 7 (8)).
Next, using the resist pattern 51a as a mask, the film pattern 30a was peeled off by dry etching (FIG. 7 (9)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the thin resist pattern 51a was peeled off (FIG. 7 (10)), and predetermined cleaning was performed to obtain a photomask 100.
In this photomask manufacturing example, the etching mask film pattern 20a is completely removed. However, the etching mask film pattern 20a is used together with the antireflection layer 13 of the light shielding film 10 or the etching mask film pattern 20a alone to prevent reflection of exposure light. In the case where it is desired to leave the corresponding part in the photomask in order to have a role, after forming the etching mask film pattern 20a (between the processes of FIGS. 7 (3) and (4)), the resist pattern 50a is changed. The film pattern 30a may be formed in a state where it is not peeled off. However, in this case, after forming the resist pattern 51a, the etching mask film pattern 20a other than the portion protected by the resist pattern 51a by dry etching with a mixed gas of chlorine and oxygen.
Need to be added (between the processes shown in FIGS. 6 (7) and (8)).

Example 4
(Production of photomask blank)
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches is used as the translucent substrate 1. A transmissivity adjusting layer 41 made of TaHf and a phase adjusting layer 42 made of SiON are formed on the translucent substrate 1.
A high-transmittance type halftone phase shift film 40 made of the above laminated film was formed. Specifically, using a target of Ta: Hf = 80: 20 (atomic% ratio) and using Ar as a sputtering gas, a TaHf film (transmittance adjusting layer: atomic ratio of Ta and Hf in the film is about 80: 20) 4
1 is formed with a film thickness of 12 nm, and then using a Si target, argon (Ar) and nitrogen monoxide (NO) are used as sputtering gas (gas flow ratio Ar: N 2 O = 20: 80), and the power of the DC power source A SiON film (phase adjustment layer) 42 having a thickness of 112 kW and a thickness of 112 nm was formed (FIG. 4). At this time, the halftone phase shift film 40 is 180 with respect to the exposure wavelength of 193 nm.
The thickness of each layer was adjusted so that a phase difference of ° was obtained. The transmittance of the halftone phase shift film 40 was 20% with respect to the wavelength of 193 nm of ArF excimer laser exposure light, and the transmittance was high.
Next, a CrN film (low reflection layer) 30 was formed on the SiON film 42 (FIG. 4). Specifically, a chromium target is used, Ar and N ₂ are set to a sputtering gas pressure of 0.1 Pa (gas flow ratio Ar: N ₂ = 4: 1), the power of the DC power source is 1.3 kW, and CrN is 20 nm. The film thickness was formed.
Next, a MoSi film (light-shielding layer) 1 is formed on the CrN film (low-reflection layer) 30 as the light-shielding film 10.
2, MoSiON film (antireflection layer) 13 was formed (FIG. 4).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar is set to a sputtering gas pressure of 0.1 Pa, the power of the DC power source is 2.0 kW, and a film made of molybdenum and silicon (MoSi film: The atomic percent ratio of Mo to Si in the film is about 21:79) with a film thickness of 14 nm, and then using a target of Mo: Si = 4: 96 (atomic percent ratio), Ar and O
₂ and N ₂ : He sputtering gas pressure 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : H
e = 5: 4: 49: 42), the power of the DC power source is 3.0 kW, and a film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic% ratio of Mo to Si in the film is about 4: 96)
Was formed with a film thickness of 10 nm. The total film thickness of the light shielding property 10 was 44 nm.
Next, the substrate was heated (annealed) at 250 ° C. for 5 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 4). Specifically, a chromium target is used, CO ₂ and N ₂ are set to a sputtering gas pressure of 0.2 Pa (gas flow ratio CO ₂ : N ₂ = 7: 2), the power of the DC power source is 1.8 kW, and CrOCN 18nm
The film thickness was formed. At this time, the film stress of the CrOCN film was adjusted to be as low as possible (preferably substantially zero film stress).
The optical density (OD) of the laminated film of the halftone phase shift film 40 and the light shielding film 10 is ArF.
It was 3.0 at a wavelength of 193 nm of excimer laser exposure light.
As described above, a photomask blank having a light-shielding film for ArF excimer laser exposure was obtained.
(Production of photomask)
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) for electron beam drawing (exposure) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 4, Fig. 8 (1))
.
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 50a (FIG. 8 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 8 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the MoSi film (light shielding layer) 1
2 and the MoSiON film (antireflection layer) 13 were dry-etched using a mixed gas of SF ₆ and He to form film patterns 12a and 13a (FIG. 8 (4)).
Next, using the film patterns 12a and 13a as a mask, the CrN film (low reflection film) 30 was dry-etched to form a film pattern 30a. At the same time, the etching mask film pattern 20a made of CrOCN is also removed by etching (FIG. 8 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, again, a chemical amplification type positive resist 51 for electron beam drawing (exposure) (FEP171: manufactured by Fuji Film Electronics Materials) has a film thickness of 300 n by spin coating.
It applied so that it might become m (FIG. 8 (6)).
Next, a desired pattern was drawn on the resist film 51 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 51a (FIG. 8 (7)). Here, the resist pattern 51a is formed for the purpose of forming a light shielding band in the outer peripheral region of the substrate.
Next, using the resist pattern 51a as a mask, the film patterns 12a and 13a were removed by dry etching (FIG. 8 (8)). SF ₆ and He as dry etching gases
The mixed gas was used.
Next, using the film pattern 30a as a mask, the SiON film (phase adjustment layer) 42 is dry-etched with a fluorine-based gas (mixed gas of CHF ₃ and He) to form a film pattern 42a (
FIG. 8 (9)).
Next, using the film patterns 30a and 42a as a mask, the TaHf film (transmittance adjusting layer) 41 is dry-etched with a chlorine-based gas (Cl ₂ gas) substantially free of oxygen to form the film pattern 4
1a was formed (FIG. 8 (10)).
Next, using the resist pattern 51a as a mask, the film pattern 30a was peeled off by dry etching (FIG. 8 (11)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the thin resist pattern 51a was peeled off (FIG. 8 (12)), and predetermined cleaning was performed to obtain a photomask 100.
In this photomask manufacturing example, the etching mask film pattern 20a is completely removed. However, the etching mask film pattern 20a is used together with the antireflection layer 13 of the light shielding film 10 or the etching mask film pattern 20a alone to prevent reflection of exposure light. In the case where it is desired to leave the corresponding part in the photomask in order to have a role, after forming the etching mask film pattern 20a (between the processes (3) and (4) in FIG. 8), the resist pattern 50a is changed. The film pattern 30a may be formed in a state where it is not peeled off. However, in this case, after forming the resist pattern 51a, the etching mask film pattern 20a other than the portion protected by the resist pattern 51a by dry etching with a mixed gas of chlorine and oxygen.
Needs to be added (between the processes shown in FIGS. 8 (7) and (8)).
Further, in this photomask manufacturing example, MoSi and Mo are mixed with a mixed gas of SF ₆ and He.
The film patterns 12a and 13a made of SiON are dry-etched (FIG. 8 (8)),
Furthermore, the SiON film (phase adjustment layer) 42 was dry-etched with a mixed gas of CHF ₃ and He to form a film pattern 42a (FIG. 8 (9)), but S was mixed with a mixed gas of CHF ₃ and He.
an iON film (phase adjusting layer) 42 and a film pattern 12a made of MoSi and MoSiON,
You may make it dry-etch 13a simultaneously.

(Example 5)
(Production of photomask blank)
FIG. 3 used in the description of the third embodiment will be used instead.
A synthetic quartz substrate having a size of 6 inches square and a thickness of 0.25 inches was used as the light transmitting substrate 1, and a MoSiN halftone phase shift film 40 was formed on the light transmitting substrate 1. Specifically, using a target of Mo: Si = 10: 90 (atomic% ratio), argon (Ar) and nitrogen (
N ₂ ) and helium (He) sputtering gas pressure 0.2 Pa (gas flow ratio Ar: N ₂
: He = 5: 50: 45), the power of the DC power source is 3.0 kW, and the film thickness is 40 nm.
An oSiN semitranslucent phase shift film 40 was formed (FIG. 3). The transmittance was adjusted to 20%.
Next, a CrN film (low reflection film) 30 was formed (FIG. 3). Specifically, a chromium target is used, and Ar and N ₂ are sputtered at a gas pressure of 0.1 Pa (gas flow ratio Ar: N ₂ = 4).
1), the power of the DC power source was 1.3 kW, and CrN was formed to a thickness of 20 nm.
Next, a MoSi film (light-shielding layer) 1 is formed on the CrN film (low-reflection film) 30 as the light-shielding film 10.
2, MoSiON film (antireflection layer) 13 was formed (FIG. 3).
Specifically, using a target of Mo: Si = 21: 79 (atomic% ratio), Ar is set to a sputtering gas pressure of 0.1 Pa, the power of the DC power source is 2.0 kW, and a film made of molybdenum and silicon (MoSi film: The atomic percent ratio of Mo to Si in the film is about 21:79) with a film thickness of 14 nm, and then using a target of Mo: Si = 4: 96 (atomic percent ratio), Ar and O
₂ and N ₂ : He sputtering gas pressure 0.2 Pa (gas flow ratio Ar: O ₂ : N ₂ : H
e = 5: 4: 49: 42), the power of the DC power source is 2.0 kW, and a film made of molybdenum, silicon, oxygen, and nitrogen (MoSiON film: the atomic% ratio of Mo to Si in the film is about 4: 96)
Was formed with a film thickness of 10 nm. The total film thickness of the light shielding film 10 was 44 nm.
Next, the substrate was heated (annealed) at 250 ° C. for 5 minutes.
Next, an etching mask film 20 was formed on the light shielding film 10 (FIG. 3). Specifically, a chromium target is used, CO and N ₂ are set to sputtering gas pressure 0.2 Pa (gas flow ratio CO ₂ : N ₂ = 7: 2), the power of the DC power source is 1.8 kW, and CrOCN is set to The film was formed with a thickness of 15 nm. At this time, the film stress of the CrOCN film was adjusted to be as low as possible (preferably substantially zero film stress).
The optical density (OD) of the laminated film of the halftone phase shift film 40, the light shielding film 10, and the etching mask film 20 was 3 at a wavelength of 193 nm of ArF excimer laser exposure light.
As described above, a photomask blank having a light-shielding film for ArF excimer laser exposure was obtained.
(Production of photomask)
On the etching mask film 20 of the photomask blank, a chemical amplification type positive resist 50 for electron beam drawing (exposure) (PRL009: manufactured by Fuji Film Electronics Materials Co., Ltd.) is applied by spin coating so that the film thickness becomes 150 nm. (Fig. 3, Fig. 9 (1))
.
Next, a desired pattern was drawn on the resist film 50 using an electron beam drawing apparatus, and then developed with a predetermined developer to form a resist pattern 50a (FIG. 9 (2)).
Next, dry etching of the etching mask film 20 was performed using the resist pattern 50a as a mask (FIG. 9 (3)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the remaining resist pattern 50a was peeled off with a chemical solution.
Next, using the etching mask film pattern 20a as a mask, the MoSi film (light shielding layer) 1
2 and the MoSiON film (antireflection layer) 13 were dry-etched using a mixed gas of SF ₆ and He to form film patterns 12a and 13a (FIG. 9 (4)).
Next, using the film patterns 12a and 13a as a mask, the CrN film (low reflection layer) 30 was dry-etched to form a film pattern 30a. At the same time, the etching mask film pattern 20a made of CrOCN is also removed by etching (FIG. 9 (5)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, again, a chemical amplification type positive resist 51 for electron beam drawing (exposure) (FEP171: manufactured by Fuji Film Electronics Materials) has a film thickness of 300 n by spin coating.
It applied so that it might become m (FIG. 9 (6)).
Next, a desired pattern was drawn on the resist film 51 using an electron beam drawing apparatus, and developed with a predetermined developer to form a resist pattern 51a (FIG. 9 (7)). Here, the resist pattern 51a is formed for the purpose of forming a light-shielding band on a large-area light-shielding portion patch, a transmittance adjustment pattern, and an outer peripheral region of the substrate.
Next, using the mask as a mask, the film patterns 12a and 13a were removed by dry etching (FIG. 9 (9)). A mixed gas of SF ₆ and He was used as the dry etching gas.
Next, using the film pattern 30a as a mask, the halftone phase shift film 40 and the translucent substrate 1 are sequentially dry-etched using a mixed gas of CHF ₃ and He to form a halftone phase shift film pattern. 40a and a substrate excavation type phase shift pattern were formed (FIG. 9 (8)). At this time, the depth at which the halftone phase shift film pattern 40a and the substrate excavation are combined to obtain a phase difference of 180 ° (the excavation depth of the translucent substrate 1 is about 70).
nm). At this time, the film patterns 12a and 13a made of MoSi and MoSiON are simultaneously removed by etching.
Next, using the resist pattern 51a as a mask, the film pattern 30a was peeled off by dry etching (FIG. 9 (9)). As a dry etching gas, a mixed gas of Cl ₂ and O ₂ (Cl ₂ : O ₂ = 4: 1) was used.
Next, the thin resist pattern 51a was peeled off (FIG. 9 (12)), and predetermined cleaning was performed to obtain a photomask 100.
In this photomask manufacturing example, the etching mask film pattern 20a is completely removed. However, the etching mask film pattern 20a is used together with the antireflection layer 13 of the light shielding film 10 or the etching mask film pattern 20a alone to prevent reflection of exposure light. In the case where it is desired to leave the corresponding part in the photomask in order to have a role, after forming the etching mask film pattern 20a (between the processes of FIGS. 9 (3) and (4)), the resist pattern 50a is changed. The film pattern 30a may be formed in a state where it is not peeled off. However, in this case, after forming the resist pattern 51a, the etching mask film pattern 20a other than the portion protected by the resist pattern 51a by dry etching with a mixed gas of chlorine and oxygen.
Needs to be added (between the processes shown in FIGS. 9 (7) and (8)).
Further, in this photomask manufacturing example, a halftone phase shift film pattern 40a, a substrate excavation type phase shift pattern are formed with a mixed gas of CHF ₃ and He, and MoS
i and consists of MoSiON film pattern 12a, but sequentially carried out removal of 13a, simultaneously or sequentially by dry etching the halftone phase shift film pattern 40a of the formation and film pattern 12a, a 13a removal by mixed gas of SF ₆ and He You may go to

(Evaluation)
The photomask obtained above was evaluated. The results are shown below.
(Thinning) First, the photomask blanks of Example 1, Reference Example 1 and Comparative Example 1, which are photomask blanks of the type used for the production of a binary photomask that does not use the phase shift effect, will be compared first. .
In the photomask blank of Comparative Example 1, 60 nm or more was necessary in order to achieve a film thickness of the light shielding film 10 of OD3 or more. Further, the thickness of the light shielding layer 12 was required to be 44 nm or more.
On the other hand, in the photomask blank of Example 1 or Reference Example 1, the thickness of the light shielding film 10 is 5
5 nm or less (specifically, 52 nm). Also, the thickness of the light shielding layer 12 can be less than 40 nm (specifically, 35 nm).
Next, the photomask blanks of Example 2 and Reference Example 2 which are photomask blanks of the type mainly used for the production of the substrate digging type phase shift mask are compared with the photomask blank of Comparative Example 1.
(Improve heat treatment resistance)
Heat treatment is performed after the light shielding film 10 is formed, and the resistance of the light shielding film 10 to the heat treatment is compared. Specifically, except that the molybdenum content ratio of the antireflection film 13 is different,
A comparison was made between the photomask blank of Example 1 and Reference Example 1, which was the light-shielding film 10 under the same conditions, and a comparison of the photomask blank of Example 2 and Reference Example 2.
FIG. 15 shows the surface reflectance distribution of the light shielding film after the heat treatment is performed on the photomask of Example 1 (because the light shielding film of Example 2 has the same configuration as the light shielding film of Example 1). Instead.) FIG. 16 shows the surface reflectance distribution of the light shielding film after the heat treatment for the photomask of Reference Example 1 (the light shielding film of Reference Example 2 has the same configuration as the light shielding film of Example 1). Because there is, replace it.)
As for the light shielding film 10 of the photomask blank of the reference examples 1 and 2, MoO precipitated on the surface by heat processing, and had become cloudy.
Further, as shown in FIG. 15, the surface reflectance distribution is deteriorated due to this. (The difference between the highest and lowest surface reflectance is 2.2%)
On the other hand, in the light-shielding film 10 of the photomask blanks of Examples 1 and 2, neither the white turbidity due to the heat treatment nor the deterioration of the surface reflectance distribution occurred (the portion with the highest surface reflectance and the portion with the lowest surface reflectance). The difference is 0.86% within the allowable range).
(Mask cleaning resistance)
The cleaning resistance of the light shielding film 10 was compared when chemical cleaning or warm water cleaning was performed on a photomask manufactured from a photomask blank. Specifically, the antireflection film 13
Example 1 and Reference Example 1 which are light-shielding films 10 under the same conditions except that the molybdenum content ratios of
The photomask blanks of Example 2 and Reference Example 2 were compared. In addition, in comparison with chemical cleaning, ammonia overwater (chemical solution mixing ratio <volume ratio> NH
₄ OH: H ₂ O ₂ : H ₂ O = 1: 1: 5), and compared with warm water cleaning, 9
Washing was performed using warm water at 0 ° C.
In Reference Examples 1 and 2, in both cases of chemical cleaning and warm water cleaning, the surface antireflection layer is dissolved by mask cleaning due to the high molybdenum content ratio, and the optical characteristics change, CD
Deterioration exceeding the allowable range of changes and cross-sectional shape changes was observed.
On the other hand, in Examples 1 and 2, since the molybdenum content ratio was minimized, in both cases of chemical cleaning and warm water cleaning, dissolution of the surface antireflection layer by mask cleaning is minimized, All of the optical characteristic change, CD change, and cross-sectional shape change were within the allowable range.
(Position accuracy improvement)
Comparison was made on the difference in positional accuracy after photomask fabrication due to the film composition of the etching mask film 20 formed on the upper surface of the light shielding film 10. Specifically, except that the film composition of the etching mask film 20 is different, a comparison between the photomask blank of Example 1 and Reference Example 1 that are substantially the same conditions, and a comparison of the photomask blank of Example 2 and Reference Example 2 are made. went.
In the photomask blanks of Reference Examples 1 and 2, since the film stress (tensile) of the etching mask film 20 made of CrN is relatively large, the substrate flatness is changed by peeling the etching mask film 20 after the photomask is manufactured. About 0.1 μm was generated, and it was found that it was difficult to achieve the position accuracy required for the double pattern of hp 45 nm and later.
On the other hand, in Examples 1 and 2, the film stress of the etching mask film made of CrOCN is Cr.
Since it can be made significantly smaller than N, the CrOCN layer 20 is formed after the photomask is manufactured.
Change in the flatness of the substrate due to peeling is suppressed to about 0.05 μm, and hp45n
The position accuracy required by the double pattern after m can be achieved.
(Membrane stress adjustment)
Comparison was made on the ease of adjusting the film stress between the respective layers of the light shielding film 10 composed of the antireflection layer 13, the light shielding layer 12, and the low reflection layer 11. Specifically, the photomask blanks of Example 1 and Reference Example 1 were compared, and the photomask blanks of Example 2 and Reference Example 2 were compared.
The antireflection layer 13 and the low reflection layer 11 made of MoSiON have a compressive stress.
In the photomask blank of Comparative Example 1, since the light shielding layer 12 is made of MoSiN and the film stress is on the compression side, the compression side antireflection layer 13 and the low reflection layer 11 become compressive stresses, and the light shielding film It is difficult to adjust the stress.
On the other hand, in the photomask blank of Example 1, the light shielding layer 12 is made of MoSi,
Since the film stress of the light-shielding film 10 is on the tension side, it is relatively easy to cancel the stress between the antireflection layer 13 and the low reflection layer 11 having the stress on the compression side. Reduction was achieved.
Further, the light shielding layer 12 made of MoSi can freely control the tensile stress and the compressive stress by adjusting the Ar gas pressure and the He gas pressure at the time of sputtering film formation and adjusting the heat treatment after film formation.

From the above, according to the present invention, a high-quality photomask suitable for the hp45 nm generation and further the hp32-22 nm generation was obtained.
In addition, with respect to the resolution of the transfer pattern formed on the mask, the transfer pattern of 50 nm can be resolved.

As mentioned above, although this invention was demonstrated using the Example, the technical scope of this invention is not limited to the range as described in the said Example. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above-described embodiments. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

It is a typical section showing an example of the photomask blank concerning Example 1 of the present invention. It is a typical cross section which shows the other example of the photomask blank which concerns on Example 2 of this invention. It is a typical cross section which shows an example of the photomask blank which concerns on Example 3 of this invention. It is a typical cross section which shows the other example of the photomask blank which concerns on Example 4 of this invention. It is a typical section for explaining the manufacturing process of the photomask concerning Example 1 of the present invention. It is a typical cross section for demonstrating the manufacturing process of the photomask which concerns on Example 2 of this invention. It is a typical cross section for demonstrating the manufacturing process of the photomask which concerns on Example 3 of this invention. It is a typical cross section for demonstrating the manufacturing process of the photomask which concerns on Example 4 of this invention. It is a typical cross section for demonstrating the manufacturing process of the photomask which concerns on Example 5 of this invention. It is a typical cross section which shows an example of the photomask blank which concerns on the reference example 1 of this invention. It is a typical cross section which shows the other example of the photomask blank which concerns on the reference example 2 of this invention. It is a typical cross section which shows the other example of the photomask blank which concerns on the comparative example 1 of this invention. It is a typical section for explaining the problem of shadowing. It is a figure which shows the relationship between the molybdenum content ratio in the thin film which consists of molybdenum silicide metals, and the optical density per unit film thickness. It is a figure regarding the surface reflectance distribution of the light shielding film after the heat processing to the photomask of Example 1. FIG. It is a figure regarding the surface reflectance distribution of the light shielding film after the heat processing to the photomask of the reference example 1. FIG.

DESCRIPTION OF SYMBOLS 1 Translucent substrate 10 Light shielding film 11 Low reflection layer 12 Light shielding layer 13 Antireflection layer 20 Etching mask film 30 Low reflection layer 40 Phase shift film 50 Resist film 100 Photomask

Claims (12)

A method for producing a photomask blank in which a light shielding film and an etching mask film are laminated on a light transmitting substrate,
The light shielding film comprises a light shielding layer and an antireflection layer,
Forming the light shielding layer made of a material containing molybdenum silicide on the translucent substrate;
In contact with the surface of the light-shielding layer, oxygen, Ri Do molybdenum silicide compound containing at least one of nitrogen, and the content of molybdenum in the whole layer is 0 atomic percent, the antireflection layer is less than 10 atomic percent Forming, and
Performing a heat treatment on the light shielding film after forming the antireflection layer and before forming the etching mask film;
Forming the etching mask film made of a material containing chromium in contact with the antireflection layer;
Performing the heat treatment at a temperature lower than the temperature of the heat treatment performed on the light-shielding film after forming the etching mask film;
A method for producing a photomask blank, comprising: The photomask blank manufacturing method according to claim 1, wherein the light shielding layer has a relatively high molybdenum content in the layer as compared with the antireflection layer. The antireflection layer, the manufacturing method of a photomask blank according to claim 1 or 2, wherein the thickness is 15nm or less. The method for manufacturing a photomask blank according to any one of claims 1 to 3 , wherein the etching mask film has a thickness of 5 nm to 30 nm. The light-shielding layer, the manufacturing method of a photomask blank according to any one of claims 1 to 4, wherein the content of molybdenum 20 atomic percent, of 40 or less atomic%. The light-shielding layer, the manufacturing method of a photomask blank according to any one of claims 1 to 5, wherein the thickness is less than 40 nm. The photomask blank according to any one of claims 1 to 6 , further comprising a step of forming a resist film having a thickness of 200 nm or less on the etching mask film after the heat treatment for the etching mask film. Production method. Before the step of forming the light shielding layer, forming a phase shift film on the translucent substrate to give a predetermined amount of phase change to the transmitted exposure light;
Forming a layer made of a material having etching selectivity with respect to an etching gas used when dry-etching the phase shift film in contact with the surface of the phase shift film;
Manufacturing method of a photomask blank according to any one of claims 1 to 7, characterized in that it comprises a. Wherein the phase shift film, a molybdenum silicide, a nitride of molybdenum silicide, oxide of molybdenum silicide, according to claim 8, characterized in that it is formed of a material mainly containing one of nitride oxides of molybdenum silicide Manufacturing method of photomask blank. Before the step of forming the light shielding layer, the pre-Symbol translucent substrate a layer of a material having an etch selectivity with respect to etching gas used when digging in dry etching, digging the transparent substrate The method for producing a photomask blank according to claim 1, further comprising a step of forming a surface in contact with the surface on the side to be embedded. A layer made of a material having etching selectivity with respect to an etching gas used when dry-etching the light-transmitting substrate or the phase shift film is made of chromium, chromium nitride, chromium oxide, chromium nitride oxide, chromium oxycarbonitride, tantalum - hafnium, tantalum - manufacturing method of a photomask blank according to any one of claims 8 10, characterized in that it is formed of a material mainly containing any of zirconium. Manufacturing method of a photomask, characterized by manufacturing a photomask using the photomask blank manufactured by the manufacturing method of a photomask blank according to any one of claims 1 to 11.