JP2020197698A - Mask blank, halftone mask, production method and production apparatus - Google Patents

Abstract

To provide a halftone mask showing little changes in a transmittance even subjected to a chemical solution treatment and having low wavelength dependency of the transmittance.SOLUTION: A mask blank is provided, including a transparent substrate S, a halftone layer 11 essentially comprising Cr, and a light-shielding layer 13 essentially comprising Cr. The halftone layer has: a chemical-resistant layer 11a located at an outermost surface in a thickness direction, in which a composition ratio of oxygen is higher than a composition ratio of chromium and than a composition ratio of nitrogen; and an optical characteristic layer 11b located close to the transparent substrate in the thickness direction and ensuring optical characteristics, in which a composition ratio of oxygen is lower than a composition ratio of chromium and a composition ratio of nitrogen.SELECTED DRAWING: Figure 1

Description

The present invention relates to techniques suitable for use in mask blanks, halftone masks, manufacturing methods, and manufacturing equipment.

Substrates for FPDs (flat panel displays, flat panel displays) such as liquid crystal displays and organic EL displays are manufactured by using multiple masks, but semi-transparent halftone masks are used to reduce the process. The number of masks can be reduced.

Furthermore, in color filters, organic EL displays, etc., photosensitive organic resin is exposed and developed using a semi-transparent mask to control the shape of the organic resin, thereby forming spacers and openings with appropriate shapes. It will be possible. For this reason, the importance of halftone masks is increasing (Patent Document 1 and the like).

These halftone masks are formed by using a light-shielding layer and a halftone layer (semi-transmissive layer). The halftone mask has two structures, one in which the semitransparent layer is formed above the light-shielding layer and the other in which the semitransparent layer is formed below.
In a halftone mask having a bottom structure, a mask can be completed by forming a laminated film of a halftone layer and a light-shielding layer, and then exposing, developing, and etching each film in a desired pattern. Therefore, the halftone mask having the lower structure has an advantage that the mask can be formed in a short period of time.

Cr is generally used as the material for the light-shielding layer of the FPD mask, and it is desirable to use Cr as the material for the halftone layer. Cr shows excellent chemical resistance, and a processing method as a mask has been established.
Further, by forming the halftone layer using Cr, there is an advantage that the wavelength dependence of the transmittance can be reduced.

When a light-shielding layer and a halftone layer are formed using Cr, etching is performed with an etching solution of Cr in order to form a desired pattern. At this time, a resist layer is laminated on the light-shielding layer or the halftone layer in order to form a region where the light-shielding layer and the halftone layer are not formed. This resist layer is removed after patterning.
As described above, in order to remove the resist layer or maintain the surface state, sulfuric acid, sulfuric acid hydrogen peroxide, and ozone were used in the mask manufacturing process to clean the light-shielding layer and / or the halftone layer, respectively. A cleaning process is required.

Japanese Unexamined Patent Publication No. 2006-106575

However, when a condition having a small wavelength dependence of transmittance is adopted in the halftone layer using the Cr material, the halftone layer is etched in the cleaning process using sulfuric acid or ozone used in the mask manufacturing process. ..
At this time, it was found that the problem that the transmittance of the halftone layer changes occurs.

In particular, when the light-shielding layer is patterned after the halftone layer is patterned, there is a problem that the change in transmittance in the halftone layer becomes larger because the etching time becomes longer.

In order to deal with this, it is also possible to perform cleaning with sulfuric acid or ozone after setting the transmittance of the halftone layer obtained by first forming a film to a low value in consideration of the change in transmittance due to cleaning. It is possible.

However, even in this case, if the change in transmittance in the cleaning step is too large, the variation in the change in transmittance in the cleaning step also becomes large. Therefore, even in this case, it has been found that it is difficult to control the transmittance, which is an important characteristic of the halftone mask, to a desired value.

The present invention has been made in view of the above circumstances, and an object of the present invention is to achieve the following objects.
1. 1. Even in the cleaning process using hydrogen peroxide or ozone, chemical resistance with little change in optical characteristics can be obtained.
2. 2. Suppresses the occurrence of changes in transmittance during the cleaning process.
3. 3. Reduce the wavelength dependence of transmittance.
4. It is possible to provide a halftone mask that satisfies these conditions at the same time.
5. Reduce the wavelength dependence of transmittance.

As a result of diligent studies, the present inventors have controlled the composition of oxygen, nitrogen and chromium in the halftone layer formed by using the Cr material, so that the change in transmittance can be changed even in the cleaning process using sulfuric acid or ozone. It was found that it is possible to obtain less chemical resistance.
Further, in the halftone layer, it is possible to improve the chemical resistance characteristics by increasing the oxygen concentration on the surface in particular, but when the oxygen concentration is increased, the wavelength dependence of the transmittance becomes large, and the oxygen concentration is further increased. It was found that if it was done too much, the chemical resistance would deteriorate.
Correspondingly, it was found that by appropriately controlling the composition of the halftone layer in the depth direction, it is possible to increase the resistance to the chemical solution and reduce the wavelength dependence of the transmittance of the halftone layer. ..
Furthermore, it was found that the wavelength dependence of the transmittance can be suppressed by controlling the sheet resistance of the halftone layer.

The mask blanks in one aspect of the present invention include a transparent substrate and
A halftone layer containing Cr as a main component laminated on the surface of the transparent substrate, and
The etching stop layer laminated on the halftone layer and
A mask blank including a light-shielding layer containing Cr as a main component laminated on the etching stop layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Solved the above-mentioned problems by having an optical characteristic layer that guarantees optical characteristics lower than the composition ratio of chromium and the composition ratio of nitrogen.
The mask blanks in one aspect of the present invention include a transparent substrate and
A light-shielding layer containing Cr as a main component laminated on the surface of the transparent substrate,
A mask blank including a Cr-based halftone layer laminated on the light-shielding layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Solved the above-mentioned problems by having an optical characteristic layer that guarantees optical characteristics lower than the composition ratio of chromium and the composition ratio of nitrogen.
In the mask blanks according to one aspect of the present invention, the composition ratio of oxygen can be reduced in the halftone layer from the outermost surface position in the thickness direction toward the position close to the transparent substrate.
The mask blanks according to one aspect of the present invention are used in the halftone layer.
The composition ratio of oxygen in the chemical resistant layer can be set to be more than four times larger than the composition ratio of the smallest oxygen in the optical characteristic layer.
The mask blanks in one aspect of the present invention have a sheet resistance in the halftone layer.
It can be set to 1.3 × 10 ³ Ω / sq or less.
The method for producing mask blanks according to one aspect of the present invention is the method for producing mask blanks according to any one of the above.
A film forming process for laminating the original halftone layer containing Cr as the main component, and
It can have an oxidation treatment step of oxidizing the original halftone layer formed in the film forming step to form the halftone layer.
In the method for producing mask blanks according to one aspect of the present invention, the original halftone layer can be oxidized with the excited oxidation treatment gas in the oxidation treatment step.
In the method for producing mask blanks in one aspect of the present invention, the oxidation-treated gas in the oxidation-treatment step can be a nitrogen oxide.
The method for producing mask blanks according to one aspect of the present invention is the method for producing mask blanks according to any one of the above.
It is possible to have a film forming step of laminating the halftone layer containing Cr as a main component.
The method for producing a halftone mask according to one aspect of the present invention is a method for producing a halftone mask using the mask blanks described in any of the above.
A step of patterning the halftone layer with a mask having a predetermined pattern, and
A cleaning process for removing the mask and
Can have.
The method for producing a halftone mask according to one aspect of the present invention is described in the cleaning step.
Sulfuric acid hydrogen peroxide or ozone water can be used as the cleaning liquid.
The halftone mask according to one aspect of the present invention can be manufactured by the above-mentioned method for manufacturing a halftone mask.
The mask blank manufacturing apparatus according to one aspect of the present invention is the manufacturing apparatus used in the mask blank manufacturing method described in any of the above.
The film forming portion for forming the original halftone layer and
It has an oxidation treatment unit that oxidizes the original halftone layer.
The oxidation treatment unit may be provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.
The mask blank manufacturing apparatus according to one aspect of the present invention is the manufacturing apparatus used in the above-mentioned mask blank manufacturing method.
It has a film forming portion for forming the halftone layer, and has a film forming portion.
The film-forming unit can be provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.

The mask blanks of the present invention have a transparent substrate and
A halftone layer containing Cr as a main component laminated on the surface of the transparent substrate, and
The etching stop layer laminated on the halftone layer and
A mask blank including a light-shielding layer containing Cr as a main component laminated on the etching stop layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Solved the above-mentioned problems by having an optical characteristic layer that guarantees optical characteristics lower than the composition ratio of chromium and the composition ratio of nitrogen.
In the mask blanks of the present invention, the composition ratio of oxygen in the halftone layer can be reduced from the outermost surface position in the thickness direction to a position close to the transparent substrate.
In the mask blanks of the present invention, in the halftone layer,
It is preferable that the composition ratio of oxygen in the chemical resistant layer is set to be more than 4 times larger than the composition ratio of the smallest oxygen in the optical characteristic layer.
Further, the method for producing a mask blank of the present invention is the method for producing a mask blank described in any of the above.
A film forming step of laminating a former halftone layer containing Cr as a main component on the transparent substrate, and
It is also possible to employ a means having an oxidation treatment step of oxidizing the original halftone layer formed in the film forming step to form the halftone layer.
In the method for producing mask blanks of the present invention, it is possible to perform the oxidation treatment of the original halftone layer with the excited oxidation treatment gas in the oxidation treatment step.
In the method for producing mask blanks of the present invention, the oxidation-treated gas in the oxidation-treatment step can be a nitrogen oxide.
Further, the method for producing the mask blanks of the present invention is the method for producing the mask blanks described in any of the above.
It is possible to have a film forming step of laminating the halftone layer containing Cr as a main component on the transparent substrate.
In the method for producing mask blanks of the present invention, the step of laminating the etching stop layer and
It can have a step of laminating the light-shielding layer.
Further, the method for manufacturing a halftone mask of the present invention is a method for manufacturing a halftone mask using the mask blanks manufactured by the above manufacturing method.
A step of patterning the halftone layer with a mask having a predetermined pattern, and
A cleaning process for removing the mask and
It is preferable to have.
In the method for producing a halftone mask of the present invention, in the cleaning step,
Sulfuric acid hydrogen peroxide or ozone water can be used as the cleaning liquid.
The halftone mask of the present invention
It can be manufactured by the above manufacturing method.
In the mask blank manufacturing apparatus of the present invention, the manufacturing apparatus used in the mask blank manufacturing method described in any of the above.
A film forming portion for forming the original halftone layer on the transparent substrate,
It has an oxidation treatment unit that oxidizes the original halftone layer.
The oxidation treatment unit may be provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.
The mask blank manufacturing apparatus of the present invention is a manufacturing apparatus used in the above-mentioned mask blank manufacturing method.
The transparent substrate has a film forming portion for forming the halftone layer.
The film-forming unit can be provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.

The mask blanks of the present invention have a transparent substrate and
A halftone layer containing Cr as a main component laminated on the surface of the transparent substrate, and
The etching stop layer laminated on the halftone layer and
A mask blank including a light-shielding layer containing Cr as a main component laminated on the etching stop layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Has an optical characteristic layer that is lower than the composition ratio of chromium and the composition ratio of nitrogen and ensures optical characteristics.
As a result, as an underlay halftone mask, the chemical resistant layer is formed so that the oxygen composition ratio is higher than the chromium composition ratio and the nitrogen composition ratio, and the chemical resistant layer maintains the chemical resistance in the mask cleaning process. be able to. Therefore, it is possible to suppress the fluctuation of the optical characteristics of the halftone layer in the cleaning step and suppress the fluctuation of the optical characteristics of the halftone mask manufactured from the mask blanks.
At the same time, the optical characteristic layer was formed so that the composition ratio of oxygen was lower than the composition ratio of chromium and the composition ratio of nitrogen, so that the optical characteristic layer halved the optical characteristics required for a halftone mask manufactured from mask blanks. The tone layer can be maintained.

The mask blanks in one aspect of the present invention include a transparent substrate and
A light-shielding layer containing Cr as a main component laminated on the surface of the transparent substrate,
A mask blank including a Cr-based halftone layer laminated on the light-shielding layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Has an optical characteristic layer that is lower than the composition ratio of chromium and the composition ratio of nitrogen and ensures optical characteristics.
As a result, as an upper halftone mask, the chemical resistant layer is formed so that the oxygen composition ratio is higher than the chromium composition ratio and the nitrogen composition ratio, and the chemical resistant layer maintains the chemical resistance in the mask cleaning process. be able to. Therefore, it is possible to suppress the fluctuation of the optical characteristics of the halftone layer in the cleaning step and suppress the fluctuation of the optical characteristics of the halftone mask manufactured from the mask blanks.
At the same time, the optical characteristic layer was formed so that the composition ratio of oxygen was lower than the composition ratio of chromium and the composition ratio of nitrogen, so that the optical characteristic layer halved the optical characteristics required for a halftone mask manufactured from mask blanks. The tone layer can be maintained.

In the mask blanks of the present invention, the composition ratio of oxygen in the halftone layer decreases from the outermost surface position in the thickness direction toward the position close to the transparent substrate.
This makes it possible to obtain mask blanks having a halftone layer capable of simultaneously maintaining chemical resistance in the cleaning process and suppression of fluctuations in optical characteristics.

In the mask blanks of the present invention, in the halftone layer,
The composition ratio of oxygen in the chemical resistant layer is set to be more than four times larger than the composition ratio of the smallest oxygen in the optical characteristic layer.
As a result, the halftone layer capable of simultaneously maintaining sufficient chemical resistance on the surface of the halftone layer exposed to the cleaning liquid and suppressing fluctuations in the optical characteristics of the halftone layer after the cleaning step due to pattern formation. It is possible to make mask blanks having.

The mask blanks in one aspect of the present invention have a sheet resistance in the halftone layer.
It is set to 1.3 × 10 ³ Ω / sq or less.
As a result, by setting the sheet resistance, it is possible to reduce the difference in transmittance depending on the wavelength of the exposure light in the halftone layer. As described above, it is possible to provide a halftone mask capable of suppressing the occurrence of a difference in transmittance depending on the wavelength of the exposure light and easily responding to the exposure light having a composite wavelength.

The method for producing mask blanks according to one aspect of the present invention is the method for producing mask blanks according to any one of the above.
A film forming process for laminating the original halftone layer containing Cr as the main component, and
It has an oxidation treatment step of oxidizing the original halftone layer formed in the film forming step to form the halftone layer.
As a result, the original halftone layer having desired optical characteristics can be easily formed by the film forming step using the conventionally known film forming conditions of a film containing Cr as a main component. Then, by oxidizing the original halftone layer by an oxidation treatment step, the chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction and the above-mentioned in the thickness direction A halftone layer having an optical characteristic layer in which the composition ratio of oxygen is lower than the composition ratio of chromium and the composition ratio of nitrogen and which guarantees optical characteristics can be formed at a position close to the transparent substrate.
At this time, it is possible to form a halftone layer that maintains the optical characteristics required as a halftone mask while forming a chemical resistant layer having sufficient chemical resistance.
Specifically, when a chemical resistant layer having a composition ratio of oxygen higher than the composition ratio of chromium and nitrogen is formed at the outermost surface position in the thickness direction, oxygen is formed at a position close to the transparent substrate in the thickness direction. It is possible to form an optical characteristic layer that guarantees optical characteristics with a composition ratio of the same as that of the original halftone layer.
Further, it is also possible to provide an upper halftone mask in which such a halftone layer is laminated on a light shielding layer. Alternatively, it is also possible to provide a lower halftone mask in which an etching stop layer and a light shielding layer are sequentially laminated on such a halftone layer.

Further, the method for producing a mask blank of the present invention is the method for producing a mask blank described in any of the above.
A film forming step of laminating a former halftone layer containing Cr as a main component on the transparent substrate, and
It has an oxidation treatment step of oxidizing the original halftone layer formed in the film forming step to form the halftone layer.
As a result, the original halftone layer having desired optical characteristics can be easily formed on the transparent substrate by the film forming step using the conventionally known film forming conditions of a film containing Cr as a main component. .. Then, by oxidizing the original halftone layer by an oxidation treatment step, the chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction and the above-mentioned in the thickness direction A halftone layer having an optical characteristic layer in which the composition ratio of oxygen is lower than the composition ratio of chromium and the composition ratio of nitrogen and which guarantees optical characteristics can be formed at a position close to the transparent substrate.
At this time, it is possible to form a halftone layer that maintains the optical characteristics required as a halftone mask while forming a chemical resistant layer having sufficient chemical resistance.
Specifically, when a chemical resistant layer having a composition ratio of oxygen higher than the composition ratio of chromium and nitrogen is formed at the outermost surface position in the thickness direction, oxygen is formed at a position close to the transparent substrate in the thickness direction. It is possible to form an optical characteristic layer that guarantees optical characteristics with a composition ratio of the same as that of the original halftone layer.

In the method for producing mask blanks of the present invention, in the oxidation treatment step, the original halftone layer is oxidized with the excited oxidation treatment gas.
As a result, when the chemical resistant layer is formed, it is possible to maintain the oxygen composition ratio at a position close to the transparent substrate in the thickness direction of the original halftone layer so as to be about the same as that of the original halftone layer. It becomes. Therefore, it is possible to form an optical characteristic layer that guarantees optical characteristics.

In the method for producing mask blanks of the present invention, the oxidation-treated gas in the oxidation-treatment step is a nitrogen oxide.
As a result, the oxidation state of the original halftone layer can be controlled to form a chemical resistant layer having sufficient chemical resistance, and at that time, at a position close to the transparent substrate in the thickness direction of the original halftone layer. , The composition ratio of oxygen can be controlled to be about the same as that of the original halftone layer.
Further, it is possible to manufacture the above-mentioned mask blanks only by controlling the atmospheric gas in the oxidation treatment step.

The method for producing mask blanks according to one aspect of the present invention is the method for producing mask blanks according to any one of the above.
It has a film forming step of laminating the halftone layer containing Cr as a main component.
This makes it possible to form a halftone layer having a chemical resistant layer and an optical characteristic layer by varying the oxygen composition ratio in the thickness direction in the step of forming the halftone layer.
At this time, the above-mentioned mask blanks can be manufactured only by controlling the atmospheric gas in the film forming process.
Further, it is also possible to provide an upper halftone mask in which such a halftone layer is laminated on a light shielding layer. Alternatively, it is also possible to provide a lower halftone mask in which an etching stop layer and a light shielding layer are sequentially laminated on such a halftone layer.

Further, the method for producing the mask blanks of the present invention is the method for producing the mask blanks described in any of the above.
It has a film forming step of laminating the halftone layer containing Cr as a main component on the transparent substrate.
This makes it possible to form a halftone layer having a chemical resistant layer and an optical characteristic layer by varying the oxygen composition ratio in the thickness direction in the step of forming the halftone layer.
At this time, the above-mentioned mask blanks can be manufactured only by controlling the atmospheric gas in the film forming process.

In the method for producing mask blanks of the present invention, the step of laminating the etching stop layer and
It has a step of laminating the light-shielding layer, which makes it possible to manufacture a halftone mask having sufficient chemical resistance and desired optical characteristics.
Here, as an etching stop layer having sufficient selectivity, it is possible to manufacture a halftone mask having an etching stop ability and having a desired pattern shape.

Further, the method for manufacturing a halftone mask of the present invention is a method for manufacturing a halftone mask using the mask blanks manufactured by the above manufacturing method.
A step of patterning the halftone layer with a mask having a predetermined pattern, and
A cleaning process for removing the mask and
Have.
As a result, an optical characteristic layer capable of simultaneously maintaining sufficient chemical resistance on the surface of the halftone layer exposed to the cleaning liquid and suppression of fluctuations in optical characteristics as the halftone layer after the cleaning step due to pattern formation. A mask blank having a halftone layer having and can produce a halftone having a desired pattern and a desired optical characteristic layer.

In the method for producing a halftone mask of the present invention, in the cleaning step,
Sulfuric acid hydrogen peroxide or ozone water is used as the cleaning liquid.
In the cleaning step, the chemical resistant layer can maintain a state in which fluctuations in optical characteristics are suppressed, and the cleaning required in this cleaning step can be performed to remove foreign substances and photomasks on the surface of the halftone layer.

The halftone mask of the present invention was manufactured by the above manufacturing method.
This makes it possible to obtain a halftone mask having desired optical characteristics.

In the mask blank manufacturing apparatus of the present invention, the manufacturing apparatus used in the mask blank manufacturing method described in any of the above.
The film forming portion for forming the original halftone layer and
It has an oxidation treatment unit that oxidizes the original halftone layer.
The oxidation treatment unit is provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.
As a result, when the chemical resistant layer is formed, the oxygen composition ratio is maintained at a position close to the transparent substrate in the thickness direction of the original halftone layer so as to be about the same as that of the original halftone layer, and optics. It is possible to manufacture mask blanks having an optical characteristic layer that guarantees the characteristics.

In the mask blank manufacturing apparatus of the present invention, the manufacturing apparatus used in the mask blank manufacturing method described in any of the above.
A film forming portion for forming the original halftone layer on the transparent substrate,
It has an oxidation treatment unit that oxidizes the original halftone layer.
The oxidation treatment unit is provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.
As a result, when the chemical resistant layer is formed, the oxygen composition ratio is maintained at a position close to the transparent substrate in the thickness direction of the original halftone layer so as to be about the same as that of the original halftone layer, and optics. It is possible to manufacture mask blanks having an optical characteristic layer that guarantees the characteristics.

The mask blank manufacturing apparatus of the present invention is a manufacturing apparatus used in the above-mentioned mask blank manufacturing method.
It has a film forming portion for forming the halftone layer, and has a film forming portion.
The film-forming unit can be provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.
As a result, when the chemical resistant layer is formed, the oxygen composition ratio is maintained at a position close to the transparent substrate in the thickness direction of the original halftone layer so as to be about the same as that of the original halftone layer, and optics. It is possible to manufacture mask blanks having an optical characteristic layer that guarantees the characteristics.

The mask blank manufacturing apparatus of the present invention is a manufacturing apparatus used in the above-mentioned mask blank manufacturing method.
The transparent substrate has a film forming portion for forming the halftone layer.
The film-forming unit can be provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas.
As a result, when the chemical resistant layer is formed, the oxygen composition ratio is maintained at a position close to the transparent substrate in the thickness direction of the original halftone layer so as to be about the same as that of the original halftone layer, and optics. It is possible to manufacture mask blanks having an optical characteristic layer that guarantees the characteristics.

According to the present invention, it has chemical resistance with little change in optical characteristics even in a cleaning process using hydrogen peroxide or ozone, it is possible to suppress the occurrence of a change in transmittance in the cleaning process, and the wavelength dependence of the transmittance is reduced. It is possible to achieve the effect that it is possible to provide a halftone mask that can be provided.

It is sectional drawing which shows 1st Embodiment of the mask blanks which concerns on this invention. It is sectional drawing which shows the 1st Embodiment of the halftone mask which concerns on this invention. It is a schematic diagram which shows the film forming apparatus in 1st Embodiment of the manufacturing method of the mask blanks which concerns on this invention. It is a schematic diagram which shows the film forming apparatus in 1st Embodiment of the manufacturing method of the mask blanks which concerns on this invention. It is a flowchart which shows 1st Embodiment of the manufacturing method of the mask blanks and a halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows 1st Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a graph which shows the Example which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a process drawing which shows the 2nd Embodiment of the manufacturing method of the halftone mask which concerns on this invention. It is a flowchart which shows 2nd Embodiment of the manufacturing method of the mask blanks and the halftone mask which concerns on this invention. It is a graph which shows the Example which concerns on this invention.

Hereinafter, the mask blanks, the halftone mask, the manufacturing method, and the first embodiment of the manufacturing apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a mask blank in the present embodiment, in which the reference numeral MB is a mask blank.

The mask blanks MB according to the present embodiment is provided for, for example, a halftone mask used in a wavelength range of 365 nm to 436 nm of exposure light.
As shown in FIG. 1, the mask blanks MB includes a transparent substrate S, a halftone layer 11 formed on the transparent substrate S, an etching stop layer 12 formed on the halftone layer 11, and an etching stop thereof. It is composed of a light-shielding layer 13 formed on the layer 12.

As the transparent substrate S, a material having excellent transparency and optical isotropic properties is used, and for example, a quartz glass substrate can be used. The size of the transparent substrate S is not particularly limited, and depends on the substrate to be exposed using the mask (for example, FPD substrate such as LCD (liquid crystal display), plasma display, organic EL (electroluminescence) display, semiconductor substrate). It will be selected as appropriate. In this embodiment, it can be applied to a substrate having a diameter of about 100 mm, a rectangular substrate having a side of about 50 to 100 mm to a side of 300 mm or more, a quartz substrate having a length of 450 mm, a width of 550 mm, and a thickness of 8 mm, and a maximum side dimension. A substrate having a thickness of 1000 mm or more and a thickness of 10 mm or more can also be used.

Further, the flatness of the transparent substrate S may be reduced by polishing the surface of the transparent substrate S. The flatness of the transparent substrate S can be, for example, 20 μm or less. As a result, the depth of focus of the mask becomes deeper, and it becomes possible to greatly contribute to the formation of fine and highly accurate patterns. Further, the flatness is as small as 10 μm or less, which is better.

The halftone layer 11 contains Cr as a main component, and is specifically selected from Cr alone and Cr oxides, nitrides, carbides, oxide nitrides, carbides, and oxide carbides. It can be configured by one, or two or more selected from these can be laminated and configured.

For example, the halftone layer 11 has a chemical resistant layer 11a at a position where it becomes the outermost surface in the thickness direction, in which the composition ratio of oxygen is higher than the composition ratio of chromium and the composition ratio of nitrogen. Further, the halftone layer 11 has an optical characteristic layer 11b whose oxygen composition ratio is lower than that of chromium and nitrogen at a position close to the transparent substrate S in the thickness direction.
The halftone layer 11 has characteristics that can withstand use as a halftone mask due to the optical characteristic layer 11b.

Further, in the halftone layer 11, the oxygen composition ratio continuously decreases from the outermost surface position close to the etching stop layer 12 to the position close to the transparent substrate S in the thickness direction. The slope of the oxygen concentration in the halftone layer 11 is set to be substantially constant with respect to the thickness direction.

The slope of the oxygen concentration in the halftone layer 11 gently decreases from the outermost surface position in the thickness direction.
Therefore, a clear boundary surface is not formed between the chemical resistant layer 11a and the optical characteristic layer 11b.

The oxygen composition ratio may be disturbed in the vicinity of the outermost surface position of the halftone layer 11 and in the vicinity of the position adjacent to the transparent substrate S. However, it is about several ATM%, and there is no problem in the chemical resistance and optical characteristics of the halftone layer 11.

In the thickness direction of the halftone layer 11, the nitrogen composition ratio continuously increases from the outermost surface position close to the etching stop layer 12 to the position close to the transparent substrate S. The slope of the nitrogen concentration in the halftone layer 11 is set to be substantially constant with respect to the thickness direction.

In the thickness direction of the halftone layer 11, the carbon composition ratio is substantially constant from the outermost surface position close to the etching stop layer 12 to the position close to the transparent substrate S. The halftone layer 11 continuously and slightly increases in the thickness direction from the outermost surface position close to the etching stop layer 12 to the position close to the transparent substrate S.

In the halftone layer 11, the composition ratio of the largest oxygen in the chemical resistant layer 11a is set to be more than four times larger than the composition ratio of the smallest oxygen in the optical characteristic layer 11b.
In the halftone layer 11, the composition ratio of the largest oxygen in the chemical resistant layer 11a is set to be more than 5 times larger than the composition ratio of the smallest oxygen in the optical characteristic layer 11b.
In the halftone layer 11, the composition ratio of the largest oxygen in the chemical resistant layer 11a is set to be slightly smaller than 6 times the composition ratio of the smallest oxygen in the optical characteristic layer 11b.

As shown in FIG. 20 described later, the chemical resistant layer 11a can be a region in which the oxygen composition ratio is higher than the carbon composition ratio or the nitrogen composition ratio in the thickness direction of the halftone layer 11.
Also in the chemical resistant layer 11a, the oxygen composition ratio decreases from the outermost surface position close to the etching stop layer 12 to the position close to the transparent substrate S in the thickness direction.

As an example, as shown in FIG. 20 described later, the oxygen composition ratio is set to be larger than 60 atm% at the outermost surface positions of the halftone layer 11 and the chemical resistant layer 11a. Further, the oxygen composition ratio is set to be larger than 65 atm% at the outermost surface positions of the halftone layer 11 and the chemical resistant layer 11a.

Further, at the outermost surface positions of the halftone layer 11 and the chemical resistant layer 11a, the composition ratio of chromium is set to be larger than 20 atm% and smaller than 30 atm%. Further, the nitrogen composition ratio is set to be smaller than 10 atm% at the outermost surface positions of the halftone layer 11 and the chemical resistant layer 11a.

Further, the composition ratio of the smallest oxygen in the optical characteristic layer 11b is set to be smaller than 15 atm%. The composition ratio of the smallest oxygen in the optical characteristic layer 11b is set to be about 10 atm%. It is not preferable that the composition ratio of the smallest oxygen in the optical characteristic layer 11b is larger than 20 atm%.

As shown in FIG. 20 described later, the optical characteristic layer 11b can be a region in which the oxygen composition ratio is lower than the carbon composition ratio or the nitrogen composition ratio in the thickness direction of the halftone layer 11.
Also in the optical characteristic layer 11b, the oxygen composition ratio decreases from the position of the chemical resistant layer 11a close to the etching stop layer 12 to the position close to the transparent substrate S in the thickness direction.
Further, the position where the composition ratio of oxygen in the optical characteristic layer 11b is the smallest is set to a position close to the transparent substrate S.

The etching stop layer 12 includes a nitrogen-containing metal silicide compound film, for example, at least one metal selected from Ni, Co, Fe, Ti, Al, Nb, Mo, W, and Hf, and these metals. Examples thereof include a film containing the alloy of the above and Si, and in particular, a molybdenum silicide compound film and a MoSi _X (X ≧ 2) film (for example, MoSi ₂ film, MoSi ₃ film, MoSi ₄ film, etc.).

For example, regarding the composition of the MoSi film, the value of X in the MoSi _X film can be in the range of 2.0 to 3.7 in the composition ratio of Mo and Si. Here, if the value of X in the MoSi _X film is reduced within this range, the etching rate can be increased. Further, if the value of X in the MoSi _X film is increased within this range, the etching rate can be lowered and increased.

The etching stop layer 12 is provided with a high nitrogen region in which the nitrogen concentration is set to 30 atm% or more at a position close to the light shielding layer 13 in the thickness direction.
The etching stop layer 12 is set so that the total film thickness of the high nitrogen region and the low nitrogen region closer to the halftone layer 11 than the high nitrogen region is 15 nm or more and 40 nm or less.

By setting the nitrogen concentration and the composition ratio of Mo and Si as the composition of the MoSi film as the etching stop layer 12, the film characteristics for etching as the etching stop layer 12, that is, the etching rate can be set. ..

As a result, in the etching of the light-shielding layer 13 located above the etching stop layer 12 (surface side, outside), the etching stop layer 12 has high selectivity and lowers the etching rate of the etching stop layer 12. The film composition can be set so that the etching stop layer 12 has etching resistance and prevents damage to the halftone layer 11.

The light-shielding layer 13 contains Cr as a main component, and specifically contains Cr and nitrogen. Further, the light-shielding layer 13 may have different compositions in the thickness direction. In this case, the light-shielding layer 13 includes Cr alone, and Cr oxides, nitrides, carbides, oxide nitrides, carbides and oxide carbonized nitrides. It can also be configured by stacking one or two or more selected from the objects.
The light-shielding layer 13 is formed with a thickness (for example, 80 nm to 200 nm) at which a predetermined optical characteristic can be obtained.

Here, the light-shielding layer 13 and the halftone layer 11 are both chromium-based thin films and are oxidatively nitrided. However, in comparison, the halftone layer 11 has a higher degree of oxidation than the light-shielding layer 13. , It is set so that it is not easily oxidized.

The mask blanks MB of the present embodiment can be applied, for example, when manufacturing a halftone mask M which is a patterning mask for an FPD glass substrate.

FIG. 2 is a cross-sectional view showing a halftone mask manufactured from the mask blanks in the present embodiment.
As shown in FIG. 2, the halftone mask M of the present embodiment has a transmission region M1, a halftone region M2, and a light-shielding region M3 in the mask blanks MB.

The transmission region M1 is an exposed region of the glass substrate (transparent substrate) S.
The halftone region M2 is a region in which only the halftone pattern 11p formed from the halftone layer 11 in the mask blanks MB is formed on the glass substrate (transparent substrate) S.

The light-shielding region M3 is a region in which a pattern is formed from the halftone layer 11, the etching stop layer 12, and the light-shielding layer 13 in the mask blanks MB, and the halftone pattern 11p, the etching stop pattern 12p, and the light-shielding pattern 13p are laminated. Etching.

In this halftone mask M, the halftone region M2 is, for example, a region capable of giving semitransparency to transmitted light in an exposure process. The light-shielding region M3 is a region capable of not transmitting the irradiation light by the light-shielding pattern 13p in the exposure process.

For example, according to the halftone mask M, in the exposure process, light in the wavelength region, particularly a composite wavelength including g-line (436 nm), h-line (405 nm), and i-line (365 nm) can be used as the exposure light. This makes it possible to perform exposure and development to control the shape of the organic resin and form spacers and openings having an appropriate shape. In addition, the pattern accuracy is greatly improved, and fine and highly accurate pattern formation becomes possible.

According to this halftone mask, it is possible to improve the pattern accuracy by using the light in the wavelength region, and it is possible to form a fine and highly accurate pattern. As a result, a high-quality flat panel display or the like can be manufactured.

Hereinafter, a method for producing the mask blanks MB of the present embodiment will be described.

The mask blanks MB in this embodiment are manufactured by the manufacturing apparatus shown in FIG. 3 or FIG.
FIG. 3 is a schematic view showing a manufacturing apparatus for manufacturing the mask blanks in the present embodiment.

The manufacturing apparatus S10 shown in FIG. 3 is an inter-back type sputtering apparatus and an apparatus capable of oxidation treatment. The manufacturing apparatus S10 is assumed to have a load / unload chamber S11, a film forming chamber (vacuum processing chamber, film forming unit) S12, and an oxidation treatment chamber (oxidation treatment unit) S13 for performing an oxidation treatment.

The load / unload chamber S11 is provided with a transport means S11a and an exhaust means S11b.
The transporting means S11a transports the glass substrate S carried in from the outside to the film forming chamber S12. The exhaust means S11b is a rotary pump or the like that draws a rough vacuum inside the load / unload chamber S11.
The load / unload chamber S11 is connected to the film forming chamber S12 via the sealing means S17.

The film forming chamber S12 is provided with a substrate holding means S12a, a cathode electrode (backing plate) S12c having a target S12b, a power supply S12d, a gas introducing means S12e, and a high vacuum exhausting means S12f.

The substrate holding means S12a receives the glass substrate S conveyed by the conveying means S11a, and holds the glass substrate S so as to face the target S12b during film formation.
The substrate holding means S12a also allows the glass substrate S to be carried in from the load / unload chamber S11. The substrate holding means S12a is also capable of carrying the glass substrate S to the load / unload chamber S11.

The target S12b is made of a material having a composition necessary for forming the original halftone layer 11A, which will be described later, on the glass substrate S.
The power supply S12d applies a negative potential sputtering voltage to the cathode electrode (backing plate) S12c having the target S12b.

The gas introducing means S12e introduces gas into the film forming chamber S12.
The high vacuum exhaust means S12f is a turbo molecular pump or the like that draws a high vacuum inside the film forming chamber S12.
The cathode electrode (backing plate) S12c, the power supply S12d, the gas introducing means S12e, and the high vacuum exhaust means S12f are configured to supply at least a material for forming the halftone layer 11.
The film forming chamber S12 is connected to the oxidation treatment chamber S13 via the sealing means S18.

The oxidation treatment chamber S13 is provided with a substrate holding means S13a, a gas introducing means S13e, a gas exciting means S13r, and a high vacuum exhaust means S13f.

The substrate holding means S13a receives the glass substrate S conveyed by the substrate holding means S12a, and holds the glass substrate S so as to face the gas excitation means S13r during the oxidation treatment.
The substrate holding means S13a also allows the glass substrate S to be carried in from the film forming chamber S12. The substrate holding means S13a is also capable of carrying the glass substrate S to the film forming chamber S12.

The gas introduction means S13e introduces gas into the oxidation treatment chamber S13.
The high vacuum exhaust means S13f is a turbo molecular pump or the like that draws a high vacuum inside the oxidation treatment chamber S13.
The gas excitation means S13r excites the gas supplied from the gas introduction means S13e to the inside of the oxidation treatment chamber S13 to obtain an excited oxidation gas.

Here, the excited oxidation gas means a state of plasma, radicals, ions and the like.
The gas excitation means S13r is capable of ejecting the excitation oxidation gas toward the glass substrate S held by the substrate holding means S13a.
The gas excitation means S13r, the gas introduction means S13e, and the high vacuum exhaust means S13f are configured to oxidize the original halftone layer 11A.
Further, the gas excitation means S13r and the gas introduction means S13e are excitation gas supply units.

In the manufacturing apparatus S10 shown in FIG. 3, the original halftone layer 11A is first formed by sputtering in the film forming chamber (vacuum processing chamber) S12 on the glass substrate S carried in from the load / unload chamber S11. To do. Then, the original halftone layer 11A is oxidized in the oxidation treatment chamber S13 to form the halftone layer 11. Then, the processed glass substrate S is carried out from the load / unload chamber S11.

At the time of film formation, the gas introduction means S12e supplies the sputtering gas and the reaction gas to the film forming chamber S12, and the sputtering voltage is applied to the backing plate (cathode electrode) S12c from an external power source. Further, a predetermined magnetic field may be formed on the target S12b by a magnetron magnetic circuit. Sputter gas ions excited by plasma in the film forming chamber S12 collide with the target S12b of the cathode electrode S12c to eject particles of the film forming material. Then, after the ejected particles and the reaction gas are combined and then adhered to the glass substrate S, a predetermined film is formed on the surface of the glass substrate S.

FIG. 4 is a schematic view showing a manufacturing apparatus for manufacturing the mask blanks in the present embodiment.
The manufacturing apparatus S20 shown in FIG. 4 is an in-line sputtering apparatus and an apparatus capable of oxidation treatment. The manufacturing apparatus S20 includes a load chamber S21, a film forming chamber (vacuum processing chamber, film forming section) S22, an oxidation treatment chamber (oxidation treatment section) S23, and an unload chamber S25.

The load chamber S21 is provided with a transport means S21a and an exhaust means S21b.
The transport means S21a transports the glass substrate S carried in from the outside to the film forming chamber S22. The exhaust means S21b is a rotary pump or the like that draws a rough vacuum inside the load chamber S21.
The load chamber S21 is connected to the film forming chamber (vacuum processing chamber) S22 via the sealing means S27.

The film forming chamber S22 is provided with a substrate holding means S22a, a cathode electrode (backing plate) S22c having a target S22b, a power supply S22d, a gas introducing means S22e, and a high vacuum exhausting means S22f.

The substrate holding means S22a receives the glass substrate S conveyed by the conveying means S21a, and holds the glass substrate S so as to face the target S22b during film formation.
The substrate holding means S22a also allows the glass substrate S to be carried in from the load chamber S21. The substrate holding means S22a is also capable of carrying the glass substrate S to the oxidation treatment chamber (oxidation treatment unit) S23.

The target S22b is made of a material having a composition necessary for forming the original halftone layer 11A, which will be described later, on the glass substrate S.
The cathode electrode (backing plate) S22c, the power supply S22d, the gas introduction means S22e, and the high vacuum exhaust means S22f are configured to supply a material for forming a film of the halftone layer 11, etc.

The power supply S22d applies a negative potential sputtering voltage to the cathode electrode (backing plate) S22c having the target S22b.
The gas introducing means S22e introduces gas into the film forming chamber S22.
The high vacuum exhaust means S22f is a turbo molecular pump or the like that draws a high vacuum inside the film forming chamber S22.
The film forming chamber S22 is connected to the oxidation treatment chamber (oxidation treatment unit) S23 via the sealing means S28.

The oxidation treatment chamber S23 is provided with a substrate holding means S23a, a gas introducing means S23e, a gas exciting means S23r, and a high vacuum exhaust means S23f.

The substrate holding means S23a receives the glass substrate S conveyed by the substrate holding means S22a, and holds the glass substrate S so as to face the gas excitation means S23r during the oxidation treatment.
The substrate holding means S23a is also capable of carrying the glass substrate S from the film forming chamber S22. The substrate holding means S23a is also capable of carrying the glass substrate S into the unload chamber S25.

The gas introducing means S23e introduces gas into the oxidation treatment chamber S23.
The high vacuum exhaust means S23f is a turbo molecular pump or the like that draws a high vacuum inside the oxidation treatment chamber S23.
The gas excitation means S23r excites the gas supplied from the gas introduction means S23e to the inside of the oxidation treatment chamber S23 to obtain an excited oxidation gas.

Here, the excited oxidation gas means a state of plasma, radicals, ions and the like.
The gas excitation means S23r is capable of ejecting the excitation oxidation gas toward the glass substrate S held by the substrate holding means S23a.
The gas excitation means S23r and the gas introduction means S23e are excitation gas supply units.

Further, these gas excitation means S23r, gas introduction means S23e, and high vacuum exhaust means S23f are configured to oxidize at least the original halftone layer 11A.
The oxidation treatment chamber (oxidation treatment unit) S23 is connected to the unload chamber S25 via the sealing means S28.

The unload chamber S25 is provided with a transport means S25a for transporting the glass substrate S carried in from the oxidation treatment chamber (oxidation treatment unit) S23 to the outside, and an exhaust means S25b such as a rotary pump that draws a rough vacuum in the chamber. Be done.

In the manufacturing apparatus S20 shown in FIG. 4, the original halftone layer 11A is first formed by sputtering in the film forming chamber (vacuum processing chamber) S22 on the glass substrate S carried in from the loading chamber S21. Then, the original halftone layer 11A is oxidized in the oxidation treatment chamber S23. Then, the glass substrate S for which the film formation has been completed is carried out from the unload chamber S25.

FIG. 5 is a flowchart showing a manufacturing process for manufacturing mask blanks and halftone masks according to the present embodiment. 6 to 10 are cross-sectional views showing a manufacturing process of mask blanks in this embodiment.
As shown in FIG. 5, the method for producing the mask blanks MB in the present embodiment includes a substrate preparation step S00, a former halftone layer forming step S01a, an oxidation treatment step S01b, and an etching stop layer forming step S02. It has a light-shielding layer film forming step S03.

Here, in the description of the method for manufacturing the mask blanks MB in the present embodiment, the processing by the manufacturing apparatus S20 shown in FIG. 4 will be described. When the mask blanks MB are manufactured by the manufacturing apparatus S10 shown in FIG. 3, the code of the S20 generation is read as the S10 generation, and the unload chamber S25 is read as the load / unload chamber S11 or the like.

In the substrate preparation step S00 shown in FIG. 5, the glass substrate S that has undergone the above-mentioned surface treatment or the like is prepared (FIG. 6). After that, the transparent substrate S is carried into the load chamber S21 shown in FIG.
In the load chamber S21, the transparent substrate S is supported by the transport means S21a, the load chamber S21 is sealed, and then the inside of the load chamber S21 is roughly evacuated by the exhaust means S21b.

In this state, the sealing means S27 is released, the transparent substrate S is conveyed by the conveying means S21a, the glass substrate S conveyed by the substrate holding means S22a is received, and the transparent substrate is sent to the film forming chamber (vacuum processing chamber) S22. Bring in S.
In the film forming chamber S22, the sealing means S27 is sealed.
In the film forming chamber (vacuum processing chamber) S22, the transparent substrate S is held by the substrate holding means S22a.

In the original halftone layer film forming step S01a shown in FIG. 5, in the film forming chamber (vacuum processing chamber) S22 shown in FIG. 4, the inside of the film forming chamber S22 is highly evacuated by the high vacuum exhaust means S22f. Then, the sputter gas and the reaction gas are supplied from the gas introducing means S22e to the film forming chamber S22, and the sputter voltage is applied to the backing plate (cathode electrode) S22c from an external power source. Further, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputter gas excited by plasma in the film forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film forming material. Then, after the ejected particles and the reaction gas are combined and then adhered to the glass substrate S, the original halftone layer 11A is formed on the surface of the glass substrate S (FIG. 7).

Here, the original halftone layer 11A is replaced with a target S22b having a composition necessary for film formation in advance. Further, as the film forming gas required for film formation of the original halftone layer 11A, a different amount of nitrogen gas or the like is supplied from the gas introducing means S22e, and the composition is set by switching so as to control the partial pressure thereof. Make it within range.
At this time, as shown in FIG. 19 described later, the original halftone layer 11A to be formed has a predetermined oxygen composition ratio, carbon composition ratio, nitrogen composition ratio, and chromium composition ratio in the thickness direction, respectively. Can have.

In the oxidation treatment step S01b shown in FIG. 5, the sealing means S28 is released from the film forming chamber S22 shown in FIG. 4, the transparent substrate S is conveyed by the substrate holding means S22a, and the glass conveyed by the substrate holding means S23a. The substrate S is received, and the transparent substrate S is carried into the oxidation treatment chamber S23.
The original halftone layer 11A is formed on the transparent substrate S.
In the oxidation treatment chamber S23, the sealing means S28 is sealed.
In the oxidation treatment chamber S23, the transparent substrate S is held by the substrate holding means S23a.

In the oxidation treatment chamber S23, the inside of the oxidation treatment chamber S23 is highly evacuated by the high vacuum exhaust means S23f. Then, the oxidation treatment gas is supplied from the gas introduction means S23e to the oxidation treatment chamber S23.
At the same time, the gas pumping means S23r excites the gas supplied from the gas introducing means S23e to the inside of the oxidation treatment chamber S23 to obtain an excited oxidation gas such as plasma, radicals, or ions.

The gas excitation means S23r ejects the excitation oxidation gas toward the surface of the original halftone layer 11A of the glass substrate S.
The original halftone layer 11A sprayed with the excitation oxidation gas is oxidized, and as shown in FIG. 20 described later, in the thickness direction, a predetermined oxygen composition ratio, carbon composition ratio, nitrogen composition ratio, and chromium The halftone layer 11 has a composition ratio (FIG. 8).

In the halftone layer 11, the chemical resistant layer 11a is formed at a position that is the outermost surface in the thickness direction. Further, in the halftone layer 11, the optical characteristic layer 11b is formed at a position close to the transparent substrate S in the thickness direction.
As described above, the chemical resistant layer 11a is formed so that the composition ratio of oxygen is higher than the composition ratio of chromium and nitrogen.
Further, the optical characteristic layer 11b is formed so that the composition ratio of oxygen is lower than the composition ratio of chromium and the composition ratio of nitrogen as described above.

At this time, as the oxidation treatment gas may be any of the original half-tone layer 11A containing chromium or the like capable oxidation, oxygen gas, carbon dioxide, as oxynitride gas N _{2 O,} NO, and adaptable.

Here, in order to form the halftone layer 11 having the chemical resistant layer 11a and the optical characteristic layer 11b, it is necessary to accurately control the oxidation state. Therefore, it is preferable that the oxidizing ability of the oxidized gas is not too strong.

For example, the oxidizing ability of the oxidizing treatment gas in the oxidation treatment step S01b is
O ₂ ＞ H ₂ O ＞ CO ₂ ＞ CO ＞ N ₂ O ＞ NO
Therefore, it is preferable to use NO gas in order to precisely control the oxidation state of chromium.
Here, the composition ratio when CO ₂ gas having a stronger oxidizing ability than NO gas is used is shown in FIG. 21 described later.

Further, the condition of the oxidation treatment gas can be controlled by the flow rate of the gas introduced into the apparatus for performing the oxidation treatment, and can be controlled by, for example, the flow rate of the oxidation treatment gas. Further, it can be treated by diluting it with a gas such as nitrogen gas or argon gas.

Further, as the excitation condition of the oxidation treatment gas, when plasma discharge is used, the excited state can be controlled by the discharge pressure or the discharge power. Further, in the sputtering apparatus, it is also possible to perform the oxidation treatment by reducing the discharge power and the film forming rate.

In the etching stop layer film forming step S02 shown in FIG. 5, the sealing means S28 shown in FIG. 4 is released, the transparent substrate S is conveyed from the oxidation treatment chamber S23 by the substrate holding means S23a, and is conveyed by the substrate holding means S22a. The glass substrate S that has been received is received, and the transparent substrate S is carried into the film forming chamber S22.

In the film forming chamber (vacuum processing chamber) S22, the inside of the film forming chamber S22 is highly evacuated by the high vacuum exhaust means S22f. Then, the sputter gas and the reaction gas are supplied from the gas introducing means S22e to the film forming chamber S22, and the sputter voltage is applied to the backing plate (cathode electrode) S22c from an external power source. Further, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputter gas excited by plasma in the film forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film forming material. Then, after the ejected particles and the reaction gas are combined, they adhere to the glass substrate S to form an etching stop layer 12 on the surface of the glass substrate S (FIG. 9).

Here, the target S22b having a composition necessary for forming the etching stop layer 12 is replaced in advance. Further, as the film forming gas required for forming the etching stop layer 12, a different amount of nitrogen gas or the like is supplied from the gas introducing means S22e, and the partial pressure is switched to be controlled, and the composition thereof is set. To be inside.

Specifically, a metal silicide film is formed as the etching stop layer 12. Although various films can be used as the metal silicid film, molybdenum silicide is used in the present mobile phone. At this time, in order to form molybdenum silicide, it can be formed by using a reactive sputtering method.

Molybdenum Silicide has the property of being very easily etched against acid or alkaline solutions if the film does not contain nitrogen. Therefore, when molybdenum silicide is used as the etching stop film, it is necessary to use molybdenum silicide containing nitrogen.

Here, when molybdenum silicide is formed by using the reactive sputtering method, nitrogen containing nitrogen, nitric oxide, nitrogen dioxide, or the like is used as the added gas. This makes it possible to form a nitrogen-containing molybdenum silicide in the film. Further, by controlling the gas flow rate of the added gas, it is possible to control the content of nitrogen contained in the molybdenum silicide.

In the light-shielding layer film forming step S03 shown in FIG. 5, the inside of the film forming chamber S22 is highly evacuated by the high vacuum exhaust means S22f in the film forming chamber (vacuum processing chamber) S22 shown in FIG. Then, the sputter gas and the reaction gas are supplied from the gas introducing means S22e to the film forming chamber S22, and the sputter voltage is applied to the backing plate (cathode electrode) S22c from an external power source. Further, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputter gas excited by plasma in the film forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film forming material. Then, after the ejected particles and the reaction gas are combined, they adhere to the glass substrate S to form a light-shielding layer 13 on the surface of the glass substrate S (FIG. 10).

Here, the target S22b having a composition necessary for forming the light-shielding layer 13 is replaced in advance. Further, as the film forming gas required for the film formation of the light-shielding layer 13, different amounts of nitrogen gas or the like are supplied from the gas introducing means S22e, and the partial pressure is switched to be controlled within the set range. To.

The light-shielding layer 13 contains chromium as a main component. At this time, in order to reduce the reflectance of the light-shielding layer 13, an antireflection layer having an increased oxygen concentration and a low refractive index can be formed on the surface of the light-shielding film.

Further, in addition to the film formation of the halftone layer 11, the etching stop layer 12, and the light-shielding layer 13, when other films are laminated, the film formation is performed by sputtering as the sputtering conditions of the corresponding target, gas, etc. The mask blanks MB of the present embodiment shown in FIG. 1 are manufactured by laminating the corresponding films according to the film forming method of.

It is possible to form halftone mask blanks having an underlay structure using a metal silicide film as an etching stop film.

Hereinafter, a method for producing the halftone mask M from the mask blanks MB of the present embodiment produced in this manner will be described.
11 to 18 are cross-sectional views showing a manufacturing process of a halftone mask using mask blanks in the present embodiment.

As shown in FIG. 5, the method for producing the halftone mask M in the present embodiment includes a photoresist layer forming step S04a, a resist pattern forming step S04b, a transmission pattern forming step S04c, a cleaning step S04d, and a photoresist layer. It has a forming step S05a, a resist pattern forming step S05b, a light-shielding pattern forming step S05c, an etching stop pattern forming step S05d, and a cleaning step S05e.

As the photoresist layer forming step S04a shown in FIG. 5, the photoresist layer PR1 is formed on the light-shielding layer 13 which is the uppermost layer of the mask blanks MB (FIG. 11). The photoresist layer PR1 may be a positive type or a negative type, but may be a positive type. As the photoresist layer PR1, a liquid resist, an adhesive film, or the like is used.

In the resist pattern forming step S04b shown in FIG. 5, the photoresist layer PR1 is exposed and developed to form a photoresist pattern PR1p having a predetermined pattern shape (opening pattern) on the light-shielding layer 13. (Fig. 12).
The photoresist pattern PR1p functions as an etching mask for the light-shielding layer 13, the etching stop layer 12, and the halftone layer 11, and the shape is appropriately determined according to the etching patterns of the respective layers 11, 12, and 13.
As an example, the photoresist pattern PR1p is set to a shape corresponding to the halftone region M2 and the light-shielding region M3, except for the transmission region M1 where the glass substrate S is exposed.

Next, as the transmission pattern forming step S04c shown in FIG. 5, the light-shielding layer 13, the etching stop layer 12, and the halftone layer 11 are wet-etched in order through the photoresist pattern PR1p using a predetermined etching solution.
At this time, in the etching of the light-shielding layer 13 and the halftone layer 11 containing chromium, an etching solution containing chromium etchant, for example, cerium nitrate diammonium nitrate can be used.

Further, in the etching of the etching stop layer 12, at least one fluorine compound selected from different etchants, for example, hydrofluoric acid, hydrofluoric acid, and ammonium hydrogen fluoride, and hydrogen peroxide, nitric acid, and sulfuric acid are selected. Those containing at least one oxidizing agent can be used.
As a result, the light-shielding layer transmission pattern 13p0, the etching stop layer transmission pattern 12p0, and the halftone pattern 11p are formed (FIG. 13).

Next, in the cleaning step S04d shown in FIG. 5, the photoresist pattern PR1p is removed using a predetermined cleaning solution.
Sulfuric acid hydrogen peroxide or ozone water can be used as the cleaning liquid.
The mask blanks MB in this state has a region in which the light-shielding layer transmission pattern 13p0, the etching stop layer transmission pattern 12p0, and the halftone pattern 11p are formed, and a transmission region M1 in which the glass substrate S is exposed (FIG. 14).

Next, as the photoresist layer forming step S05a shown in FIG. 5, the photoresist layer PR2 is formed on the light-shielding layer transmission pattern 13p0, which is the uppermost layer of the mask blanks MB. At this time, the photoresist layer PR2 is also formed in the transmission region M1 (FIG. 15).
The photoresist layer PR2 may be a positive type or a negative type, but may be a positive type. A liquid resist is used as the photoresist layer PR2.

Subsequently, in the resist pattern forming step S05b shown in FIG. 5, the photoresist pattern PR2p is formed on the light-shielding layer transmission pattern 13p0 by exposing and developing the photoresist layer PR2 (FIG. 16).
The photoresist pattern PR2p functions as an etching mask for the light-shielding layer transmission pattern 13p0 and the etching stop layer transmission pattern 12p0.

The shape of the photoresist pattern PR2p is appropriately determined according to the etching pattern of the halftone region M2 for removing the light-shielding layer transmission pattern 13p0 and the etching stop layer transmission pattern 12p0.
As an example, the photoresist pattern PR2p is set in the halftone region M2 to have an opening width corresponding to the opening width dimensions of the light-shielding pattern 13p and the etching stop pattern 12p to be formed.

Next, as the light-shielding pattern forming step S05c shown in FIG. 5, a step of wet-etching the light-shielding layer transmission pattern 13p0 through the photoresist pattern PR2p with a predetermined etching solution (etchant) is started.

When etching the light-shielding layer transmission pattern 13p0, it is important that the etching stop layer transmission pattern 12p0 is not etched by the etching solution of the light-shielding layer transmission pattern 13p0.
When the light-shielding layer transmission pattern 13p0 containing chromium as a main component is used, an etching solution containing cerium nitrate secondary ammonium nitrate can be used as the etching solution.

Further, it is preferable to use cerium nitrate diammonium containing an acid such as nitric acid or perchloric acid.
It is common to use a mixed solution of dicerium ammonium nitrate and perchloric acid as the etching solution.

Here, the etching stop layer transmission pattern 12p0 has higher resistance to this etching solution than the light-shielding layer transmission pattern 13p0. Therefore, first, only the light-shielding layer transmission pattern 13p0 is patterned to form the light-shielding pattern 13p.
The light-shielding pattern 13p has an opening width corresponding to the photoresist pattern PR2p, and is removed in a shape corresponding to the halftone region M2. The light-shielding pattern 13p is formed in a shape corresponding to the light-shielding region M3 (FIG. 17).

At this time, the etching stop layer transmission pattern 12p0 has a necessary selection ratio with respect to the etching solution, and the etching rate is set to be extremely small. Therefore, the etching stop layer transmission pattern 12p0 has sufficient etching resistance. Therefore, the halftone layer 11 having Cr of the same system as the light shielding layer 13 is not damaged.

Next, as the etching stop pattern forming step S05d shown in FIG. 5, a step of wet-etching the etching stop layer transmission pattern 12p0 over the photoresist pattern PR2p and the light-shielding pattern 13p with a predetermined etching solution is started.

When the etching stop layer 12 is MoSi, the etching solution includes at least one fluorine compound selected from fluorine-based, that is, hydrofluoric acid, hydrofluoric acid, and ammonium hydrogenfluoride. , It is preferable to use one containing at least one oxidizing agent selected from hydrogen peroxide, nitric acid and sulfuric acid.

In the wet etching of the etching stop layer transmission pattern 12p0, the etching stop layer transmission pattern 12p0 is etched in the halftone region M2 not covered by the light shielding pattern 13p to form the etching stop pattern 12p (FIG. 18).

When the etching stop layer transmission pattern 12p0 is etched and the halftone layer 11 is exposed, the etching of the etching stop layer 12 is completed. As a result, the halftone pattern 11p is exposed in the halftone region M2.

Next, as the cleaning step S05e shown in FIG. 5, the photoresist pattern PR2p is removed.
Sulfuric acid hydrogen peroxide or ozone water can be used as the cleaning liquid.
At this time, the washing water does not come into contact with the halftone pattern 11p in the light-shielding region M3 in which the light-shielding pattern 13p is laminated. On the other hand, in the halftone region M2, the washing water comes into contact with the halftone pattern 11p.

In cleaning the halftone pattern 11p, the chemical resistant layer 11a is arranged on the exposed surface.
The chemical resistant layer 11a has the above-mentioned composition ratio of oxygen and the like, and thus has chemical resistance to a cleaning liquid such as sulfuric acid hydrogen peroxide or ozone water. Therefore, the chemical resistant layer 11a prevents the optical characteristic layer 11b from being changed in film thickness and optical characteristics due to the cleaning liquid in the cleaning step S05e.

Therefore, the chemical resistant layer 11a can prevent changes in the film thickness and optical characteristics due to the cleaning liquid from occurring in the halftone pattern 11p in the cleaning step S05e.
As a result, in the halftone pattern 11p, the optical characteristics can be ensured by the optical characteristic layer 11b.

As a result, as shown in FIG. 2, it has a predetermined light-shielding pattern 13p and an etching stop pattern 12p that are optically set, and a halftone pattern 11p having desired optical characteristics, and has a transmission region M1 and a halftone region. It is possible to obtain a halftone mask M in which M2 and a light-shielding region M3 are formed.

Alternatively, in the process step described above, after processing the molybdenum silicide film to be the etching stop layer 12, the halftone layer 11 containing chromium as a main component is etched using the molybdenum silicide film as a mask. After that, by peeling off the resist layer, the step of processing the light-shielding layer 13, the etching stop layer 12, and the halftone layer 11 can be completed.
Here, it is also possible to form a pattern of only the halftone layer 11 by etching only the light-shielding layer transmission pattern 13p0 and the etching stop layer transmission pattern 12p0.

According to the mask blanks MB of the present embodiment, as shown in FIG. 1, the halftone layer 11 has a chemical resistant layer 11a and an optical characteristic layer 11b to manufacture a halftone mask M having desired optical characteristics. can do.
Further, the original halftone layer 11A is formed by the original halftone layer film forming step S01a, and the original halftone layer 11A is oxidized by the oxidation treatment step S01b, whereby the half having chemical resistance and suppression of fluctuations in optical characteristics is obtained. The tone layer 11 can be formed.
As a result, the halftone mask M having desired optical characteristics can be manufactured only by adding the oxidation treatment step S01b to the conventional manufacturing step.

Further, according to the mask blanks MB of the present embodiment, as shown in FIG. 2, it is possible to simultaneously maintain the chemical resistance in the cleaning step S05e and the suppression of fluctuations in the optical characteristics, and the mask blanks MB have desired optical characteristics. Halftone mask M can be manufactured.

Hereinafter, the mask blanks, the halftone mask, the manufacturing method, and the second embodiment of the manufacturing apparatus according to the present invention will be described with reference to the drawings.
26 to 37 are process diagrams showing a method for manufacturing a halftone mask according to the present embodiment, and FIG. 38 is a flowchart showing a method for manufacturing a mask blank and a halftone mask according to the present embodiment.
In the present embodiment, the difference from the first embodiment described above is that the stacking position of the halftone layer is related, and the other configurations corresponding to the first embodiment described above are designated by the same reference numerals. The explanation is omitted.

As shown in FIG. 33, the mask blanks MB according to the present embodiment includes a transparent substrate S, a light-shielding layer 13 formed on the transparent substrate S, and a halftone layer 11 formed on the light-shielding layer 13. It is composed.
The light-shielding layer 13 may have a light-shielding pattern 13p.

The halftone layer 11 has a chemical resistant layer 11a at a position where it becomes the outermost surface in the thickness direction, in which the composition ratio of oxygen is higher than the composition ratio of chromium and the composition ratio of nitrogen. Further, the halftone layer 11 has an optical characteristic layer 11b in which the composition ratio of oxygen is lower than the composition ratio of chromium and the composition ratio of nitrogen at a position close to the transparent substrate S in the thickness direction and the light-shielding pattern 13p.
The composition ratio in the halftone layer 11 has the same configuration as that of the first embodiment described above.

As shown in FIG. 37, the halftone mask M of the present embodiment has a transmission region M1, a halftone region M2, and a light-shielding region M3 in the mask blanks MB.

The transmission region M1 is an exposed region of the glass substrate (transparent substrate) S.
The halftone region M2 is a region in which only the halftone pattern 11p formed from the halftone layer 11 in the mask blanks MB is formed on the glass substrate (transparent substrate) S.

The light-shielding region M3 is a region in which a pattern is formed from the light-shielding layer 13 and the halftone layer 11 in the mask blanks MB, and the light-shielding pattern 13p and the halftone pattern 11p are laminated.

As shown in FIG. 38, the methods for manufacturing mask blanks and halftone masks in the present embodiment include a substrate preparation step S00, a light-shielding layer film forming step S011, a photoresist layer forming step S012a, and a resist pattern forming step S012b. , Light-shielding pattern forming step S012c, cleaning step S012d, original halftone layer forming step S013a, oxidation treatment step S013b, photoresist layer forming step S014a, resist pattern forming step S014b, and transmission pattern forming step S014c. , And the cleaning step S014d.

Here, in the description of the method for manufacturing the mask blanks in the present embodiment, the processing by the manufacturing apparatus S20 shown in FIG. 4 will be described as in the first embodiment. When the mask blanks MB are manufactured by the manufacturing apparatus S10 shown in FIG. 3, the code of the S20 generation is read as the S10 generation, and the unload chamber S25 is read as the load / unload chamber S11 or the like. In the present embodiment, the operation of the manufacturing apparatus S20 will be omitted as appropriate.

In the substrate preparation step S00 shown in FIG. 38, the glass substrate S is prepared (FIG. 26). After that, the transparent substrate S is carried into the film forming chamber (vacuum processing chamber) S22 via the load chamber S21 shown in FIG. In the film forming chamber (vacuum processing chamber) S22, the transparent substrate S is supported by the substrate holding means S22a.

In the light-shielding layer film forming step S011 shown in FIG. 38, in the film forming chamber (vacuum processing chamber) S22 shown in FIG. 4, the gas introducing means S22e supplies the sputtering gas and the reaction gas to the film forming chamber S22, and externally A sputtering voltage is applied from the power source to the backing plate (cathode electrode) S22c. Further, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputter gas excited by plasma in the film forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film forming material. Then, after the ejected particles and the reaction gas are combined, they adhere to the glass substrate S to form a light-shielding layer 13 on the surface of the glass substrate S (FIG. 27).

The light-shielding layer 13 contains chromium as a main component. Here, the target S22b having a composition necessary for forming the light-shielding layer 13 is replaced in advance. Further, as the film forming gas required for the film formation of the light-shielding layer 13, different amounts of nitrogen gas or the like are supplied from the gas introducing means S22e, and the partial pressure is switched to be controlled within the set range. To.
After that, the glass substrate S is carried out to the outside through the unload chamber S25 shown in FIG.

As the photoresist layer forming step S012a shown in FIG. 38, the photoresist layer PR1 is formed on the light-shielding layer 13 which is the uppermost layer of the mask blanks (FIG. 28). The photoresist layer PR1 may be a positive type or a negative type, but may be a positive type. As the photoresist layer PR1, a liquid resist, an adhesive film, or the like is used.

In the resist pattern forming step S012b shown in FIG. 38, the photoresist pattern PR1p having a predetermined pattern shape (opening pattern) is formed on the light-shielding layer 13 by exposing and developing the photoresist layer PR1. (Fig. 29).
The photoresist pattern PR1p functions as an etching mask for the light-shielding layer 13, and its shape is appropriately determined according to the etching pattern of the light-shielding layer 13.
As an example, the photoresist pattern PR1p is set to a shape corresponding to the light-shielding region M3 except for the transmission region M1 and the halftone region M2 where the glass substrate S is exposed.

Next, in the light-shielding pattern forming step S012c shown in FIG. 38, the light-shielding layer 13 is wet-etched through the photoresist pattern PR1p with a predetermined etching solution to form the light-shielding pattern 13p (FIG. 30).
At this time, in the etching of the light-shielding layer 13 containing chromium, an etching solution containing chromium etchant, for example, cerium nitrate diammonium nitrate can be used.

Next, in the cleaning step S012d shown in FIG. 38, the photoresist pattern PR1p is removed using a predetermined cleaning solution. Sulfuric acid hydrogen peroxide or ozone water can be used as the cleaning liquid.
The mask blanks MB in this state has a light-shielding region M3 in which the light-shielding pattern 13p is formed, and regions M1 and M2 in which the glass substrate S is exposed (FIG. 31).

Next, the transparent substrate S is carried into the film forming chamber (vacuum processing chamber) S22 shown in FIG.
In the original halftone layer film forming step S013a shown in FIG. 38, in the film forming chamber (vacuum processing chamber) S22 shown in FIG. 4, the gas introducing means S22e supplies the sputtering gas and the reaction gas to the film forming chamber S22. A sputtering voltage is applied to the backing plate (cathode electrode) S22c from an external power source. Further, a predetermined magnetic field may be formed on the target S22b by a magnetron magnetic circuit.

Ions of the sputter gas excited by plasma in the film forming chamber S22 collide with the target S22b of the cathode electrode S22c to eject particles of the film forming material. Then, after the ejected particles and the reaction gas are combined, they adhere to the glass substrate S and the light-shielding pattern 13p to form the original halftone layer 11A on the surfaces of the glass substrate S and the light-shielding pattern 13p (FIG. 32). ..

Here, the original halftone layer 11A is replaced with a target S22b having a composition necessary for film formation in advance. Further, as the film forming gas required for film formation of the original halftone layer 11A, a different amount of nitrogen gas or the like is supplied from the gas introducing means S22e, and the composition is set by switching so as to control the partial pressure thereof. Make it within range.
At this time, the original halftone layer 11A to be formed into a film can have a predetermined oxygen composition ratio, carbon composition ratio, nitrogen composition ratio, and chromium composition ratio, respectively, in the thickness direction.

In the oxidation treatment step S013b shown in FIG. 38, the transparent substrate S is carried from the film forming chamber S22 shown in FIG. 4 to the oxidation treatment chamber S23.
The original halftone layer 11A is formed on the transparent substrate S. In the oxidation treatment chamber S23, the transparent substrate S is held by the substrate holding means S23a.

In the oxidation treatment chamber S23, the inside of the oxidation treatment chamber S23 is highly evacuated by the high vacuum exhaust means S23f. Then, the oxidation treatment gas is supplied from the gas introduction means S23e to the oxidation treatment chamber S23.
At the same time, the gas pumping means S23r excites the gas supplied from the gas introducing means S23e to the inside of the oxidation treatment chamber S23 to obtain an excited oxidation gas such as plasma, radicals, or ions.

The gas excitation means S23r ejects the excitation oxidation gas toward the surface of the original halftone layer 11A of the glass substrate S.
The original halftone layer 11A sprayed with the excitation oxidation gas is oxidized and has a predetermined oxygen composition ratio, carbon composition ratio, nitrogen composition ratio, and chromium composition ratio in the thickness direction, respectively. (Fig. 33).

In the halftone layer 11, the chemical resistant layer 11a is formed at a position that is the outermost surface in the thickness direction. Further, in the halftone layer 11, the optical characteristic layer 11b is formed at a position close to the transparent substrate S in the thickness direction and the light-shielding pattern 13p.
As described above, the chemical resistant layer 11a is formed so that the composition ratio of oxygen is higher than the composition ratio of chromium and nitrogen.
Further, the optical characteristic layer 11b is formed so that the composition ratio of oxygen is lower than the composition ratio of chromium and the composition ratio of nitrogen as described above.

At this time, as the oxidation treatment gas may be any of the original half-tone layer 11A containing chromium or the like capable oxidation, oxygen gas, carbon dioxide, as oxynitride gas N _{2 O,} NO, and adaptable.

Here, in order to form the halftone layer 11 having the chemical resistant layer 11a and the optical characteristic layer 11b, it is necessary to accurately control the oxidation state. Therefore, it is preferable that the oxidizing ability of the oxidized gas is not too strong.

For example, the oxidizing ability of the oxidizing treatment gas in the oxidation treatment step S01b is
O ₂ ＞ H ₂ O ＞ CO ₂ ＞ CO ＞ N ₂ O ＞ NO
Therefore, it is preferable to use NO gas in order to precisely control the oxidation state of chromium.

Further, the condition of the oxidation treatment gas can be controlled by the flow rate of the gas introduced into the apparatus for performing the oxidation treatment, and can be controlled by, for example, the flow rate of the oxidation treatment gas. Further, it can be treated by diluting it with a gas such as nitrogen gas or argon gas.

Further, as the excitation condition of the oxidation treatment gas, when plasma discharge is used, the excited state can be controlled by the discharge pressure or the discharge power. Further, in the sputtering apparatus, it is also possible to perform the oxidation treatment by reducing the discharge power and the film forming rate.

In the oxidation treatment step S01b, the oxidation state is precisely controlled to reduce the sheet resistance of the halftone layer 11.
1.3 × 10 Set to ³ Ω / sq or less.
Furthermore, the sheet resistance of the halftone layer 11 is
It can also be set to 7.0 × 10 ² Ω / sq or higher.
After that, the glass substrate S is carried out to the outside through the unload chamber S25 shown in FIG.

Next, as the photoresist layer forming step S014a shown in FIG. 38, the photoresist layer PR2 is formed on the chemical resistant layer 11a of the halftone layer 11 which is the uppermost layer of the mask blanks MB. At this time, the photoresist layer PR2 is formed in the transmission region M1, the halftone region M2, and the light-shielding region M3 (FIG. 34).
The photoresist layer PR2 may be a positive type or a negative type, but may be a positive type. A liquid resist is used as the photoresist layer PR2.

Subsequently, in the resist pattern forming step S014b shown in FIG. 38, the photoresist pattern PR2p is formed on the chemical resistant layer 11a of the halftone layer 11 by exposing and developing the photoresist layer PR2 (FIG. 35). ..
The photoresist pattern PR2p functions as an etching mask for the halftone layer 11.

The shape of the photoresist pattern PR2p is appropriately determined according to the etching pattern of the transmission region M1 from which the halftone layer 11 is removed.
The photoresist pattern PR2p is set to a shape corresponding to the halftone region M2 and the light-shielding region M3, excluding the transmission region M1 that exposes the glass substrate S.

Next, as the transmission pattern forming step S014c shown in FIG. 38, a step of wet-etching the halftone layer 11 with a predetermined etching solution (etchant) through the photoresist pattern PR2p is started.
When the halftone layer 11 containing chromium as a main component is used, an etching solution containing cerium nitrate secondary ammonium nitrate can be used as the etching solution.

Further, it is preferable to use cerium nitrate diammonium containing an acid such as nitric acid or perchloric acid.
It is common to use a mixed solution of dicerium ammonium nitrate and perchloric acid as the etching solution.
The halftone pattern 11p has an opening shape corresponding to the photoresist pattern PR2p, and is removed into a shape corresponding to the halftone region M2 and the light-shielding region M3. The halftone pattern 11p is formed in a shape corresponding to the transmission region M1 (FIG. 36).

Next, as the cleaning step S014d shown in FIG. 38, the photoresist pattern PR2p is removed.
Sulfuric acid hydrogen peroxide or ozone water can be used as the cleaning liquid.
At this time, in the light-shielding region M3 and the halftone region M2, the washing water comes into contact with the halftone pattern 11p.

In cleaning the halftone pattern 11p, the chemical resistant layer 11a is arranged on the exposed surface.
The chemical resistant layer 11a has the above-mentioned composition ratio of oxygen and the like, and thus has chemical resistance to a cleaning liquid such as sulfuric acid hydrogen peroxide or ozone water. Therefore, the chemical resistant layer 11a prevents the optical characteristic layer 11b from being changed in the film thickness and the optical characteristics due to the cleaning liquid in the cleaning step S014d.

Therefore, the chemical resistant layer 11a can prevent changes in the film thickness and optical characteristics due to the cleaning liquid from occurring in the halftone pattern 11p in the cleaning step S014d.
As a result, in the halftone pattern 11p, the optical characteristics can be ensured by the optical characteristic layer 11b.

At the same time, by setting the sheet resistance of the halftone layer 11 as described above, it is possible to reduce the difference in transmittance caused by the wavelength difference of the exposure light in the halftone region M2.
The relationship between the sheet resistance of the halftone layer 11 and the difference in transmittance caused by the wavelength difference of the exposure light in the halftone region M2 is shown in FIG. 39 as described later.

As a result, as shown in FIG. 37, it has a predetermined light-shielding pattern 13p optically set and a halftone pattern 11p having desired optical characteristics, and has a transmission region M1, a halftone region M2, and a light-shielding region M3. A halftone mask M in which and is formed can be obtained.

According to the mask blanks MB of the present embodiment, as shown in FIG. 33, the halftone layer 11 has the chemical resistant layer 11a and the optical characteristic layer 11b to manufacture a halftone mask M having desired optical characteristics. can do.

Further, the original halftone layer 11A is formed by the original halftone layer film forming step S013a, and the original halftone layer 11A is oxidized by the oxidation treatment step S013b, thereby suppressing fluctuations in chemical resistance and optical characteristics and transmitting by wavelength. It is possible to form the halftone layer 11 having the rate difference suppression.

As a result, the halftone mask M having desired optical characteristics can be manufactured only by adding the oxidation treatment step S013b to the conventional manufacturing step. Moreover, the halftone mask M that does not require the formation of an etching stop pattern can be manufactured without providing the etching stop layer.

Further, by setting the sheet resistance of the halftone layer 11, it is possible to reduce the difference in transmittance of the halftone layer 11 depending on the wavelength of the exposure light. In this way, it is possible to manufacture a halftone mask M capable of suppressing the occurrence of a difference in transmittance depending on the wavelength of the exposure light and easily responding to the exposure light having a composite wavelength. ..

According to the present embodiment, it is possible to manufacture a so-called top-mounted halftone mask M in which the halftone layer 11 is formed on the upper portion of the light-shielding pattern 13p. Even in the top-mounted halftone mask M, when the halftone pattern 11p is formed, the cleaning step S014d using ozone, sulfuric acid hydrogen peroxide, or the like is performed.

If the transmittance of the halftone mask fluctuates in the cleaning step S014d or the like, when a pattern is formed using the mask, the resist pattern to be exposed cannot obtain a desired shape. Occurs.

Therefore, by using the halftone mask of the present embodiment, the transmittance difference (change in transmittance) at the exposure wavelength is reduced, and then the change in transmittance in the halftone layer 11 after the cleaning step S014d using the chemical solution is performed. It becomes possible to suppress.

In the top-mounted halftone mask, first, a chromenium film to be a light-shielding layer 13 is formed on a glass substrate. Then, in order to form a desired pattern, the chromenium film is patterned using a resist process. After that, the halftone layer 11 formed of the chromium film is formed. At this time, by applying the present invention, it is possible to form a halftone layer having little variation in transmittance even in the cleaning step.

After that, the halftone layer can be subsequently formed into a desired pattern by a resist process to form a top-mounted halftone mask.

Hereinafter, examples of the present invention will be described.

As a specific example of the mask blanks and the halftone mask in the present invention, first, the production of the mask blanks will be described.

<Experimental example>
First, a semi-transparent halftone film is formed on a glass substrate for forming a mask.
Here, first, a film is formed as a film having the same composition ratio of chromium, oxygen, nitrogen, carbon, etc. as in the conventional case, and then an oxidation treatment is performed.

The halftone film formed at this time is preferably a film containing chromium, oxygen, nitrogen, carbon and the like. By controlling the composition and film thickness of chromium, oxygen, nitrogen, and carbon contained in the halftone film at the time of film formation and at the time of oxidation treatment, it is possible to obtain a halftone film having a desired transmittance.

After that, a metal silicide film is formed as an etching stop film. Various films can be used as the metal silicide film, but in this embodiment, molybdenum silicide is used. At this time, in order to form molybdenum silicide, it can be formed by using a reactive sputtering method.

Molybdenum Silicide has the property of being very easily etched against acid or alkaline solutions if the film does not contain nitrogen. Therefore, when molybdenum silicide is used as the etching stop layer, nitrogen-containing molybdenum silicide is used.

Here, when molybdenum silicide is formed by using the reactive sputtering method, nitrogen-containing nitrogen, nitric oxide, nitrogen dioxide, or the like is used as the additive gas to form nitrogen-containing molybdenum silicide in the film. It is possible. Further, in this case, it is possible to control the content of nitrogen contained in the molybdenum silicide by controlling the gas flow rate of the added gas.

Then, a light-shielding layer containing chromium as a main component is formed.
At this time, in order to reduce the reflectance of the light-shielding layer, an antireflection layer having an increased oxygen concentration and a low refractive index is formed on the surface of the light-shielding layer. In this way, halftone mask blanks having an underlay structure with a metal silicide film as an etching stop layer are formed.

Further, when forming a halftone mask, first, a resist process is used to process the light-shielding film into a desired pattern through the process steps of resist coating, exposure, development, etching, and resist peeling. Here, when etching the light-shielding film, it is important that the etching stop film is not etched by the etching solution of the light-shielding film. When a light-shielding film containing chromium as a main component is used, it is common to use a mixed solution of dicerium ammonium nitrate and perchloric acid as the etching solution.

When molybdenum Silicide is used as the etching stop film, it functions as a good etching stop film because molybdenum silicide is hardly etched with respect to the etching solution of chromiumnium.

Next, for the molybdenum silicide film, the etching stop film is processed in the same manner by using the resist process.
The etching solution used for etching the molybdenum silicide film here is a solution containing hydrofluoric acid and an oxidizing agent.

After processing the molybdenum silicide film to be the etching stop film, the halftone film containing chromium as the main component is etched using the molybdenum silicide film as a mask. After that, the resist film is peeled off to complete the process of processing the light-shielding film, the etching stop film, and the halftone film.

As described above, in the bottom-mounted halftone mask M, a patterning step using a resist is required at least twice. Therefore, in the patterning step, the number of steps in which each film is treated with the etching solution or the cleaning solution is increased as compared with the top-mounted halftone mask.

For this reason, the lower-mounted halftone mask M in which the halftone layer 11 is formed before the light-shielding layer 13 is required to have high chemical resistance.
Further, when the transmittance of the halftone layer 11 is set to be high, such as 40% or more, it is necessary to set the film thickness of the halftone layer 11 to be thin. For this reason, if the chemical resistance of the halftone layer 11 is low, the change in transmittance becomes large, so that higher chemical resistance is required.

Further, the importance of a flat halftone film in which the wavelength dependence of the transmittance of the halftone layer 11 is reduced is increasing.
In the panel exposure process in FPD, the processing speed of exposure is very important, so unlike the exposure process in semiconductors, multi-wavelength light is used in the exposure process.

Generally, exposure is performed using g-line (436 nm), h-line (405 nm), and i-line (365 nm), which are strong emission line spectra of a high-pressure mercury lamp. For this reason, it is desirable that the transmittances at these wavelengths are as close as possible to each other.
For this reason, it has been common to use a metallic chromium film that has not been oxidized so much as a halftone film.

However, it has been found that the following problems occur when a chromium film that is relatively unoxidized is used as a halftone film. This problem is caused by etching the halftone film in the cleaning step using a mixed solution of sulfuric acid and hydrogen peroxide solution (sulfuric acid superwater) used as the cleaning step of the mask and the ozone cleaning step. The transmittance changes.

On the other hand, the chemical resistance can be improved by strengthening the oxidation of the halftone film, but if the oxygen concentration in the film is too high, there arises a problem that the wavelength dependence of the transmittance becomes large. In order to solve such a problem, in this embodiment, the oxygen concentration on the surface of the halftone film is increased to appropriately control the oxygen concentration on the surface, and the oxygen concentration is decreased in the depth direction of the halftone film. By doing so, it is possible to improve the chemical resistance characteristics while keeping the wavelength dependence of the transmittance below a certain level.

<Experimental example 1>
As Experimental Example 1, a halftone film having the same composition ratio as the conventionally used halftone film was formed.
The composition of this halftone film was evaluated using Auger electron spectroscopy without performing oxidation treatment on the formed halftone film.
The result is shown in FIG.
The halftone film whose composition is evaluated in FIG. 19 can be used as the original halftone layer 11A described above.

<Experimental example 2>
As Experimental Example 2, after forming the same halftone film as in Experimental Example 1, an oxidation treatment was performed using NO gas.
In this case as well, the composition of the halftone film after the oxidation treatment was evaluated by using Auger electron spectroscopy as in Experimental Example 1.
The result is shown in FIG.

<Experimental example 3>
As Experimental Example 3, after forming the same halftone film as in Experimental Example 1, oxidation treatment was performed using CO ₂ gas.
In this case as well, the composition of the halftone film after the oxidation treatment was evaluated by using Auger electron spectroscopy as in Experimental Example 1.
The result is shown in FIG.

From these results, the halftone film of Experimental Example 1 whose composition was evaluated in FIG. 19 had a low oxygen concentration in the film, and was oxidized using NO gas and CO ₂ gas as in Experimental Example 2 and Experimental Example 3. It can be seen that the oxygen concentration on the surface of the halftone film can be increased by performing the above.
By performing the oxidation treatment using NO gas and CO ₂ gas as in Experimental Example 2 and Experimental Example 3, the film thickness of the halftone film is increased, and the position in the thickness direction of the corresponding halftone film is increased. 19 to 22 are shown by arrows, respectively.

Further, by comparing Experimental Example 2 of FIG. 20 with Experimental Example 3 of FIG. 21, Experimental Example 2 was subjected to oxidation treatment using NO gas as compared with the case of Experimental Example 3 using CO ₂ gas. It can be seen that it is possible to increase the oxygen concentration only on the surface of the halftone film.
It is considered that this is because the oxidizing power when the CO ₂ gas is excited by plasma is higher than that of the NO gas.

Further, the transmittance of these halftone films in h-line, the difference in transmittance between g-line and i-line, the film thickness, and the change in transmittance after washing with sulfuric acid hydrogen peroxide were measured.
These results are shown in Table 1.

From this result, it can be seen that in Experimental Examples 2 and 3 in which the oxidation treatment was performed, it is possible to suppress the change in the transmittance of the halftone film before and after the sulfuric acid depopulation washing.

Further, in Experimental Examples 2 and 3 subjected to the oxidation treatment, the difference in transmittance between the g-ray and the i-line is larger than that of the experimental example 1 halftone film not subjected to the oxidation treatment.

Furthermore, the halftone film of Experimental Example 2 subjected to the oxidation treatment with NO gas has a transmittance of g-ray and i-line as compared with the halftone film of Experimental Example 3 having been oxidized with CO ₂ gas. It is possible to reduce the difference between. It is considered that this is because NO gas can suppress the oxidation inside the halftone film by the oxidation treatment and strengthen the oxidation on the surface of the halftone film.

Next, in order to obtain a halftone film having strong chemical resistance and less wavelength dependence of transmittance, the halftone film is subjected to oxidation treatment using various NO gases to change the surface oxygen concentration in the halftone film. , The change in transmittance of the formed halftone film before and after washing with sulfuric acid overwater was investigated.

<Experimental Example 4>
As Experimental Example 4, the surface oxygen concentration in the halftone film was changed, and the relationship between the surface oxygen concentration in the halftone film and the change in transmittance before and after washing with sulfuric acid hydrogen peroxide was investigated.
The result is shown in FIG.

<Experimental Example 5>
As Experimental Example 5, the relationship between the surface nitrogen concentration of the halftone film and the change in transmittance before and after washing with sulfuric acid hydrogen peroxide was investigated.
The result is shown in FIG.

From the results of Experimental Examples 4 and 5, it was found that the oxygen concentration on the surface of the halftone film is preferably 40% or more and the nitrogen concentration is 20% or less in order to enhance the resistance to sulfuric acid hydrogen peroxide.
The range of preferable composition ratios is shown in FIGS. 22 and 23, respectively.

Next, in order to obtain a halftone film having strong chemical resistance and less wavelength dependence of transmittance, the halftone film is subjected to oxidation treatment using various NO gases to change the surface oxygen concentration in the halftone film. , The change in the spectral transmittance characteristics of the formed halftone film was investigated.

<Experimental example 6>
Similar to Experimental Example 4, the surface oxygen concentration in the halftone film was changed, and as Experimental Example 6, the relationship between the surface oxygen concentration of the halftone film and the difference in transmittance between the g-line and i-line was investigated. did.
The result is shown in FIG.

<Experimental Example 7>
Similar to Experimental Example 5, the surface nitrogen concentration in the halftone film was changed, and as Experimental Example 7, the relationship between the surface nitrogen concentration in the halftone film and the difference in transmittance between the g-line and i-line was investigated. did.
The result is shown in FIG.

Generally, the difference between the transmittance of g-line and the transmittance of i-line required for a halftone mask is about 0.6%.
Examining from the results of Experimental Examples 6 and 7, it was found that the oxygen concentration on the surface of the halftone film satisfying the above criteria is preferably 55% or less, and the nitrogen concentration is preferably 15% or more.
The range of preferable composition ratios is shown in FIGS. 24 and 25, respectively.

From the results of the studies so far, in order to obtain a halftone film with high chemical resistance and low wavelength dependence of transmittance, the halftone film is oxidized with NO gas to surface the halftone film. It can be seen that it is desirable to increase the oxygen concentration in the membrane and decrease the oxygen concentration in the membrane.

Further, it can be seen that it is desirable that the oxygen concentration on the surface of the halftone film is 40% or more and 55% or less, and the nitrogen concentration is 15% or more and 20% or less.
By applying this halftone film to a lower halftone mask, a halftone mask with little change in transmittance and a small wavelength dependence of transmittance can be obtained even if the chemical treatment required in the mask manufacturing process is performed. It turns out that is possible.

In the above-described embodiment, the lower-mounted halftone mask having many chemical treatment steps has been described as an example, but the present invention is based on the upper-mounted halftone mask in which the halftone film is formed on the light-shielding film. The invention can also be applied.
This makes it possible to manufacture a top-mounted halftone mask having strong chemical resistance and low wavelength dependence of transmittance.

Further, in the above embodiment, the original halftone layer formed into the film is oxidized to form the halftone layer 11. However, the oxidation-treated gas is supplied at the time of film formation, and the oxygen concentration is used as the composition ratio described above. The layer 11 can also be formed.
In this case, the film forming chambers S12 and S22 can be provided with an oxidation treatment gas supply unit capable of supplying the oxidation treatment gas, and the oxidation treatment chambers S13 and S23 can not be provided.

<Experimental Example 8>
As Experimental Example 8, after forming the same halftone film as in Experimental Examples 1 to 7, oxidation treatment was performed using NO gas or the like. Furthermore, the sheet resistance was measured in the halftone film after the oxidation treatment.
In Experimental Example 8, by changing the oxidation conditions, and the sheet resistance of ^{0.7 × 10 3 Ω / sq~1.3 ×} 10 3 Ω / sq.

Further, in the halftone film in which the sheet resistance was changed, the transmittance of each of them was measured using g-line (436 nm) and i-line (365 nm) light.
The value of the difference between the g-line transmittance and the i-line transmittance (ΔT (g-i line) (%)) was calculated.
The result is shown in FIG.

From this result, the relationship between the transmittance difference between the g-line (436 nm) and the i-line (365 nm) of the halftone film using the present invention and the sheet resistance becomes higher as the sheet resistance increases. It was found that the transmittance difference became large.

The oxygen concentration of the halftone film of the present invention changes significantly in the film thickness direction, and the oxygen concentration near the surface of the halftone film is high. For this reason, it can be seen that the oxygen concentration increases as the oxidation conditions in the oxidation step become stronger, and the sheet resistance of the halftone film increases accordingly.

From this, the effect of the present invention can be obtained by changing the resistivity of the halftone film in the depth direction to increase the resistivity near the surface of the halftone film and lower the resistivity of the lower layer. You can see that you can.
Moreover, it was found that the halftone film of the present invention can suppress the change in the transmittance difference before and after the wet etching.

Examples of utilization of the present invention include masks and mask blanks for semiconductors and flat displays.

MB ... Mask blanks M ... Halftone mask M1 ... Transmission area M2 ... Halftone area M3 ... Light-shielding area S ... Glass substrate (transparent substrate)
PR2, PR2 ... Photoresist layer PR1p, PR2p ... Photoresist pattern 11 ... Halftone layer 11a ... Chemical resistant layer 11b ... Optical characteristic layer 11A ... Original halftone layer 11p ... Halftone pattern 12 ... Etching stop layer 12p0 ... Etching stop layer transmission Pattern 12p ... Etching stop pattern 13 ... Light-shielding layer 13p0 ... Light-shielding layer transmission pattern 13p ... Light-shielding pattern

Claims (14)

With a transparent board
A halftone layer containing Cr as a main component laminated on the surface of the transparent substrate, and
The etching stop layer laminated on the halftone layer and
A mask blank including a light-shielding layer containing Cr as a main component laminated on the etching stop layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Is a mask blank having an optical characteristic layer that is lower than the composition ratio of chromium and the composition ratio of nitrogen and ensures optical characteristics. With a transparent board
A light-shielding layer containing Cr as a main component laminated on the surface of the transparent substrate,
A mask blank including a Cr-based halftone layer laminated on the light-shielding layer.
The halftone layer has a chemical resistant layer having an oxygen composition ratio higher than the chromium composition ratio and the nitrogen composition ratio at the outermost surface position in the thickness direction, and an oxygen composition ratio at a position close to the transparent substrate in the thickness direction. Is a mask blank having an optical characteristic layer that is lower than the composition ratio of chromium and the composition ratio of nitrogen and ensures optical characteristics. The mask blank according to claim 1 or 2, wherein in the halftone layer, the composition ratio of oxygen decreases from the outermost surface position in the thickness direction toward a position close to the transparent substrate. In the halftone layer
The mask blank according to any one of claims 1 to 3, wherein the composition ratio of oxygen in the chemical resistant layer is set to be more than 4 times larger than the composition ratio of the smallest oxygen in the optical characteristic layer. In the halftone layer, the sheet resistance
The mask blank according to any one of claims 1 to 4, wherein the mask blank is set to 1.3 × 10 ³ Ω / sq or less. The method for producing mask blanks according to any one of claims 1 to 5.
A film forming process for laminating the original halftone layer containing Cr as the main component, and
A method for producing mask blanks, which comprises an oxidation treatment step of oxidizing the original halftone layer formed in the film forming step to form the halftone layer. The method for producing mask blanks according to claim 6, wherein in the oxidation treatment step, the original halftone layer is oxidized with the excited oxidation treatment gas. The method for producing mask blanks according to claim 7, wherein the oxidation-treated gas in the oxidation-treatment step is a nitrogen oxide. The method for producing mask blanks according to any one of claims 1 to 5.
A method for producing mask blanks, which comprises a film forming step of laminating the halftone layer containing Cr as a main component. A method for producing a halftone mask using the mask blanks according to any one of claims 1 to 5.
A step of patterning the halftone layer with a mask having a predetermined pattern, and
A cleaning process for removing the mask and
A method for manufacturing a halftone mask, which comprises. In the cleaning step
The method for producing a halftone mask according to claim 10, wherein hydrogen peroxide or ozone water is used as the cleaning liquid. A halftone mask produced by the production method according to claim 10 or 11. A manufacturing apparatus used in the method for manufacturing mask blanks according to any one of claims 6 to 8.
The film forming portion for forming the original halftone layer and
It has an oxidation treatment unit that oxidizes the original halftone layer.
An apparatus for producing mask blanks, wherein the oxidation treatment unit is provided with an excitation gas supply unit capable of exciting and supplying the oxidation treatment gas. A manufacturing apparatus used in the method for manufacturing mask blanks according to claim 9.
It has a film forming portion for forming the halftone layer, and has a film forming portion.
An apparatus for producing mask blanks, wherein the film forming portion is provided with an excitation gas supply portion capable of exciting and supplying an oxidation treatment gas.

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