TW202121047A - Photomask blank and photomask capable of providing a predetermined optical density with low reflectance and obtaining an appropriate cross-sectional shape - Google Patents

Abstract

The present invention provides a photomask blank having a mask layer serving as a photomask. The mask layer includes a lower anti-reflection layer laminated on a transparent substrate, a light-shielding layer provided at a position spaced farther apart from the transparent substrate than the lower anti-reflection layer, and an upper anti-reflection layer provided at a position spaced farther apart from the transparent substrate than the light-shielding layer.

Description

Mask base and mask

The present invention relates to a photomask substrate and a photomask, in particular to a binary photomask substrate with low reflection on both sides, or a preferred technology for the manufacture of a binary photomask substrate.

In the manufacture of masks for large panels such as FPD (flat panel display), a mask substrate with a light-shielding layer is used as a binary mask. In addition, with the high definition of FPD, it is more necessary to form fine patterns. In such a mask base, as a mask layer including a patterned light-shielding layer, etc., a structure in which a film including a chromium material is laminated on a transparent substrate such as glass is generally used (Patent Document 1).

In order to produce fine patterns, as a countermeasure against stray light during pattern formation, it is necessary to achieve low reflectivity of the front and back of the mask substrate (for example, the reflectivity of light exposed to a wavelength of 436 nm is less than 5%). As the film structure of the mask base to achieve low reflectivity of the front and back, for example, it is known that an anti-reflective layer (back), a light-shielding layer, and an anti-reflective layer (front) are laminated on a glass substrate with at least three layers. The mask layer of the layer structure. When such an anti-reflection layer is provided, in order to obtain a film with a lower refractive index as the anti-reflection layer, an oxidized chromium oxide film or the like can be used. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2001-305716

[The problem to be solved by the invention]

However, the etching rate of the chromium oxide film with a higher oxygen concentration becomes lower. As a result, when a chromium oxide film with a higher oxygen concentration is used as the anti-reflection layer, the anti-reflection layer has a lower etching rate than the light-shielding layer, so the etching of the anti-reflection layer does not progress.

Therefore, when making the mask pattern, the etching of the light-shielding layer is more advanced than that of the anti-reflection layer, so that the etching amount toward the side of the mask substrate, that is, the side etching amount becomes uneven in the thickness direction. Specifically, it is known that there is a problem in that the central part of the thickness direction of the mask layer is etched unnecessarily, resulting in a cross-sectional shape formed with eaves and flanges.

In order to make the cross-sectional shape of the pattern perpendicular to the surface of the glass substrate, the etching rate of each layer must be consistent. However, in order to maintain the optical characteristics of each layer, the composition ratio is different, so the difference in the etching rate is unavoidably large. Therefore, it is impossible to realize a mask substrate capable of forming a vertical pattern cross-sectional shape.

Furthermore, in the pattern formation of the photomask substrate, in order to improve the contrast, it is required to correspond to a higher optical density (for example, OD5) than the previous optical density (OD3). In order to respond to the above requirements, it is necessary to make the difference between the oxygen concentration of the light shielding layer and the oxygen concentration of the anti-reflection layer larger. Therefore, the difference in the etching rate between the light shielding layer and the anti-reflection layer becomes larger.

Therefore, the deviation from vertical, which is the allowable cross-sectional shape under the previous optical density (OD3), becomes inadmissible under higher optical density (for example, OD5).

The present invention is completed in view of the above situation, and achieves the following objectives, namely, to provide a photomask substrate, which has a specific optical density with low reflectivity, can make the etching rate of the light-shielding layer and the anti-reflection layer close, and can Form an appropriate cross-sectional shape with reduced eaves and flanging. [Technical means to solve the problem]

A photomask base of one form of the present invention has a mask layer that becomes a photomask. The mask layer has: a lower anti-reflection layer laminated on a transparent substrate; and a light-shielding layer disposed on the lower anti-reflection layer A position farther away from the transparent substrate; and the upper anti-reflection layer is arranged at a position farther away from the transparent substrate than the light shielding layer. The lower anti-reflective layer contains chromium, oxygen, nitrogen, and carbon oxynitride film, the content of chromium contained in the lower anti-reflective layer is 25 atm%-50 atm%, and the oxygen contained in the lower anti-reflective layer The content rate is 30 atm%～50 atm%, the nitrogen content contained in the lower anti-reflection layer is 10 atm%～30 atm%, and the carbon content contained in the lower anti-reflection layer is 2 atm%～ 5 atm%. The light-shielding layer includes a nitride film of chromium and nitrogen, the content of chromium in the light-shielding layer is 70 to 95 atm%, and the nitrogen content is 5 to 20 atm%. The upper anti-reflection layer contains chromium, oxygen, nitrogen, and carbon oxynitride film. The content of chromium contained in the upper anti-reflection layer is 25 atm%-50 atm%, and the oxygen contained in the upper anti-reflection layer The content rate is 55 atm%～70 atm%, the nitrogen content contained in the upper anti-reflection layer is 5 atm%～20 atm%, and the carbon content contained in the upper anti-reflection layer is 2 atm%～ 5 atm%. With this, the above-mentioned problems are solved.

A photomask base of one form of the present invention has a mask layer that becomes a photomask. The mask layer has: a lower anti-reflection layer laminated on a transparent substrate; and a light-shielding layer disposed on the lower anti-reflection layer A position farther away from the transparent substrate; and the upper anti-reflection layer is arranged at a position farther away from the transparent substrate than the light shielding layer. The lower anti-reflective layer contains chromium, oxygen, nitrogen, and carbon oxynitride film, the content of chromium contained in the lower anti-reflective layer is 25 atm%-50 atm%, and the oxygen contained in the lower anti-reflective layer The content rate is 30 atm%～50 atm%, the nitrogen content contained in the lower anti-reflection layer is 10 atm%～30 atm%, and the carbon content contained in the lower anti-reflection layer is 2 atm%～ 5 atm%. The light-shielding layer contains a carbonitride film of chromium, nitrogen and carbon, the content of chromium in the light-shielding layer is 70 atm%～95 atm%, and the content of nitrogen in the light-shielding layer is 5 atm%～ 20 atm%, the carbon content of the above-mentioned light-shielding layer is 0 atm%-15 atm%. The upper anti-reflection layer contains chromium, oxygen, nitrogen, and carbon oxynitride film. The content of chromium contained in the upper anti-reflection layer is 25 atm%-50 atm%, and the oxygen contained in the upper anti-reflection layer The content rate is 55 atm%～70 atm%, the nitrogen content contained in the upper anti-reflection layer is 5 atm%～20 atm%, and the carbon content contained in the upper anti-reflection layer is 2 atm%～ 5 atm%. In this way, the above-mentioned problems are solved.

In the photomask substrate of one aspect of the present invention, the reflectivity of both sides of the above-mentioned mask layer under exposure light with a wavelength of 365 nm to 436 nm is less than 10%.

In the photomask substrate of one aspect of the present invention, the reflectivity of both sides of the above-mentioned mask layer under exposure light with a wavelength of 436 nm is less than 5%.

In the photomask base of one aspect of the present invention, the film thickness of the lower anti-reflection layer, the film thickness of the light-shielding layer, and the thickness of the upper anti-reflection layer are set in the mask layer so that the optical density becomes 3.0 or more Film thickness.

In one form of the photomask substrate of the present invention, the film thickness of the lower anti-reflection layer is 25.0 nm to 35.0 nm, the film thickness of the light shielding layer is 125.0 nm to 135.0 nm, and the film thickness of the upper anti-reflection layer is 25.0 nm～35.0 nm.

In the photomask substrate of one aspect of the present invention, the film thickness of the mask layer is 175.0 nm-205.0 nm.

In one aspect of the photomask base of the present invention, there is a photoresist layer disposed at a position farther away from the transparent substrate than the mask layer.

The photomask of one aspect of the present invention is manufactured from the photomask substrate of the above aspect.

A photomask base of one form of the present invention has a mask layer that becomes a photomask. The mask layer has: a lower anti-reflection layer laminated on a transparent substrate; and a light-shielding layer disposed on the lower anti-reflection layer A position farther away from the transparent substrate; and the upper anti-reflection layer is arranged at a position farther away from the transparent substrate than the light shielding layer. The lower anti-reflective layer contains chromium, oxygen, nitrogen, and carbon oxynitride film, the content of chromium contained in the lower anti-reflective layer is 25 atm%-50 atm%, and the oxygen contained in the lower anti-reflective layer The content rate is 30 atm%～50 atm%, the nitrogen content contained in the lower anti-reflection layer is 10 atm%～30 atm%, and the carbon content contained in the lower anti-reflection layer is 2 atm%～ 5 atm%. The light-shielding layer includes a nitride film of chromium and nitrogen, the content of chromium in the light-shielding layer is 70 to 95 atm%, and the nitrogen content is 5 to 20 atm%. The upper anti-reflection layer contains chromium, oxygen, nitrogen, and carbon oxynitride film. The content of chromium in the upper anti-reflection layer is 25 atm%-50 atm%, more preferably 30 atm%-50 atm %, the oxygen content contained in the upper anti-reflection layer is 55 atm%～70 atm%, the nitrogen content contained in the upper anti-reflection layer is 5 atm%-20 atm%, and the content of the upper anti-reflection layer is 5 atm%～20 atm%. The carbon content is 2 atm%～5 atm%. With this, the above-mentioned problems are solved.

Thereby, the patterned cross-sectional shape can be classified into an appropriate range while maintaining the low reflectivity of both sides of the mask layer and the necessary optical density. Specifically, with respect to the upper and lower anti-reflection layers, the side etching of the light-shielding layer becomes a specific range, and the light-shielding layer can be prevented from being dented. Therefore, when the photomask is manufactured, the cross-sectional shape of the photomask substrate during patterning (resist coating, exposure, development, and etching) can be made as vertical as possible. The size of the pattern affected by the cross-sectional shape of the pattern can be made into a specific range, so that a high-definition mask can be realized.

A photomask base of one form of the present invention has a mask layer that becomes a photomask. The mask layer has: a lower anti-reflection layer laminated on a transparent substrate; and a light-shielding layer disposed on the lower anti-reflection layer A position farther away from the transparent substrate; and the upper anti-reflection layer is arranged at a position farther away from the transparent substrate than the light shielding layer. The lower anti-reflective layer contains chromium, oxygen, nitrogen, and carbon oxynitride film, the content of chromium contained in the lower anti-reflective layer is 25 atm%-50 atm%, and the oxygen contained in the lower anti-reflective layer The content rate is 30 atm%～50 atm%, the nitrogen content contained in the lower anti-reflection layer is 10 atm%～30 atm%, and the carbon content contained in the lower anti-reflection layer is 2 atm%～ 5 atm%. The light-shielding layer contains a carbonitride film of chromium, nitrogen and carbon, the content of chromium in the light-shielding layer is 70 atm%～95 atm%, and the content of nitrogen in the light-shielding layer is 5 atm%～ 20 atm%, the carbon content of the above-mentioned light-shielding layer is 0 atm%-15 atm%. The upper anti-reflection layer contains chromium, oxygen, nitrogen, and carbon oxynitride film. The content of chromium in the upper anti-reflection layer is 25 atm%-50 atm%, more preferably 30 atm%-50 atm %, the oxygen content contained in the upper anti-reflection layer is 55 atm%～70 atm%, the nitrogen content contained in the upper anti-reflection layer is 5 atm%-20 atm%, and the content of the upper anti-reflection layer is 5 atm%～20 atm%. The carbon content is 2 atm%～5 atm%. With this, the above-mentioned problems are solved.

Thereby, the patterned cross-sectional shape can be classified into an appropriate range while maintaining the low reflectivity of both sides of the mask layer and the necessary optical density. Specifically, with respect to the upper and lower anti-reflection layers, the lateral etching of the light-shielding layer becomes a specific range, and the light-shielding layer can be prevented from being dented. Therefore, when the photomask is manufactured, the cross-sectional shape of the photomask substrate (resist coating, exposure, development, and etching) can be made as vertical as possible. The size of the pattern affected by the cross-sectional shape of the pattern can be made into a specific range, so that a high-definition mask can be realized.

In the mask substrate of one aspect of the present invention, on both sides of the above-mentioned mask layer, the reflectivity under the exposure light with a wavelength of 365 nm to 436 nm can be 10% or less, especially the exposure light with a wavelength of 436 nm The reflectivity below is below 5%. Thereby, by setting the composition ratio of each layer in the above-mentioned range, a preferable cross-sectional shape can be realized, and a range of low reflectance required for patterning can be realized. Furthermore, as the above-mentioned reflectance, the transparent substrate side includes the reflectance of the transparent substrate.

In the photomask base of one aspect of the present invention, the film thickness of the lower anti-reflection layer, the film thickness of the light-shielding layer, and the upper anti-reflection layer can also be set such that the optical density of the mask layer becomes 3.0 or more The film thickness. Thereby, by setting the composition ratio of each layer in the above-mentioned range, a preferable cross-sectional shape can be realized, and the range of optical density required for patterning can be realized.

In the photomask substrate of one aspect of the present invention, the film thickness of the lower anti-reflection layer can be 25.0 nm to 35.0 nm, the film thickness of the light shielding layer is 125.0 nm to 135.0 nm, and the film thickness of the upper anti-reflection layer The thickness is 25.0 nm～35.0 nm. Thereby, by setting the composition ratio of each layer in the above-mentioned range, a preferable cross-sectional shape can be realized, and the range of optical density required for patterning can be realized.

In the photomask substrate of one aspect of the present invention, the film thickness of the mask layer may also be 175.0 nm-205.0 nm. Thereby, by setting the composition ratio of each layer to the above range, a preferable cross-sectional shape can be realized, and the range of optical density required for patterning and the range of low reflectance required for patterning can be realized.

In one form of the photomask base of the present invention, there may be a photoresist layer disposed at a position farther away from the transparent substrate than the mask layer.

The photomask of one aspect of the present invention can be manufactured from any of the photomask substrates described above. [Effects of Invention]

According to the present invention, it is possible to provide the effect of providing a mask substrate that has a specific optical density with a low reflectivity, the etching rate of the light-shielding layer and the anti-reflection layer can be close, and the eaves and flanging can be formed appropriately. The cross-sectional shape.

Hereinafter, the photomask substrate, the photomask, the manufacturing method of the photomask substrate, and the manufacturing method of the photomask according to the first embodiment of the present invention will be described based on the drawings. FIG. 1 is a cross-sectional view of the mask substrate of this embodiment, and FIG. 2 is a cross-sectional view of the mask substrate of this embodiment. In the figure, the symbol 10B is the mask substrate.

In the mask substrate 10B of this embodiment, the wavelength of the light for exposure is a binary mask (mask) used in the range of about 365 nm to 436 nm. As shown in FIG. 1, the mask base 10B of this embodiment includes: a glass substrate (transparent substrate) 11, a lower anti-reflection layer 12 formed on the glass substrate 11, and a light shielding layer 13 formed on the lower anti-reflection layer 12 , And an anti-reflection layer 14 formed on the light-shielding layer 13.

That is, the light shielding layer 13 is located farther away from the glass substrate 11 than the lower anti-reflection layer 12. In addition, the upper anti-reflection layer 14 is disposed at a position farther away from the glass substrate 11 than the light shielding layer 13. The lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14 have the optical characteristics required as a mask to form a low-reflection laminated film, that is, a mask layer.

Furthermore, the mask substrate 10B of the present embodiment may also be configured as follows. That is, as shown in FIG. 1, the mask layer formed by laminating the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, such as As shown in FIG. 2, a photoresist layer 15 is formed in advance.

Furthermore, in addition to the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14, the mask substrate 10B of this embodiment can also be made of a chemical corrosion resistant layer, a protective layer, an adhesion layer, an etching stop layer, etc. Laminated structure. Furthermore, on these laminated films, a photoresist layer 15 may be formed as shown in FIG. 2.

As the glass substrate (transparent substrate) 11, a material excellent in transparency and optical isotropy can be used, for example, a quartz glass substrate can be used. The size of the glass substrate 11 is not particularly limited, and can be appropriately selected according to the substrate exposed by the mask (for example, LCD (liquid crystal display), plasma display, organic EL (electroluminescence, electroluminescence) display and other FPD substrates, etc.) .

In this embodiment, as the glass substrate (transparent substrate) 11, a rectangular substrate with a side of about 100 mm to a side of 2000 mm or more can be used, and a substrate with a thickness of 1 mm or less, a substrate with a thickness of several mm, Or a substrate with a thickness of 10 mm or more.

In addition, the flatness of the glass substrate 11 may be reduced by grinding the front surface of the glass substrate 11. The flatness of the glass substrate 11 can be set to 20 μm or less, for example. Thereby, the depth of focus of the mask becomes deeper, which can make a great contribution to the formation of fine and high-precision patterns. Furthermore, the flatness is preferably a smaller value of 10 μm or less.

The lower anti-reflection layer 12 has Cr (chromium) as a main component. The lower anti-reflection layer 12 includes C (carbon), O (oxygen), and N (nitrogen). Furthermore, the lower anti-reflection layer 12 may also have a different composition in the thickness direction. Furthermore, in this case, as the lower anti-reflection layer 12, a single component of Cr and one selected from oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides of Cr may also be used. Material, or two or more kinds of materials are laminated. The thickness of the lower anti-reflective layer 12 and the composition ratio (atm%) of Cr, N, C, O, etc., are set in a manner to obtain specific optical characteristics and etching rate as described below.

For example, the lower anti-reflection layer 12 is a carbon oxynitride film containing chromium, oxygen, nitrogen, and carbon, and the composition ratio of the lower anti-reflection layer 12 can be set to a chromium content (chromium concentration) of 25 atm%-50 atm%, The oxygen content (oxygen concentration) is 30 atm%～50 atm%, the nitrogen content (nitrogen concentration) is 10 atm%～30 atm%, and the carbon content (carbon concentration) is 2 atm%～5 atm%.

The film thickness of the lower anti-reflective layer 12 can be set according to the required optical characteristics of the lower anti-reflective layer 12, and varies according to the composition ratio of Cr, N, C, O, etc. The film thickness of the lower anti-reflection layer 12 can be set to 25.0 nm to 35.0 nm.

Thereby, the lower anti-reflection layer 12 can set the reflectance of the glass substrate 11 to be less than 5% under the light exposure in the wavelength range of about 365 nm to 436 nm, especially the wavelength of 436 nm.

The light shielding layer 13 has Cr (chromium) as a main component. The light shielding layer 13 contains N (nitrogen). Furthermore, the light shielding layer 13 may have a different composition in the thickness direction. Furthermore, in this case, as the light shielding layer 13, a single component of Cr and one material selected from oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides of Cr may be used. Or two or more materials are layered together. The light-shielding layer 13 is described below to set the thickness of the light-shielding layer 13 and the composition ratio (atm%) of Cr, N, C, O, etc., in order to obtain specific optical characteristics and etching rate.

For example, the light-shielding layer 13 is a nitride film containing chromium and nitrogen, and the chromium content can be set to 70 atm% to 95 atm%, and the nitrogen content to 5 atm% to 20 atm%. Or the light-shielding layer 13 is a carbonitride film containing chromium, nitrogen, and carbon. The content of chromium can be set to 70 atm%～95 atm%, the content of nitrogen is 5 atm%～20 atm%, and the content of carbon is It is 0 atm%～15 atm%.

The film thickness of the light-shielding layer 13 can be set according to the optical characteristics required by the light-shielding layer 13, and can be changed according to the composition ratio of Cr, N, C, O, etc. The film thickness of the light shielding layer 13 can be set to 125.0 nm to 135.0 nm.

The upper anti-reflection layer 14 has Cr (chromium) as a main component. The upper anti-reflection layer 14 includes C (carbon), O (oxygen), and N (nitrogen). Furthermore, the upper anti-reflection layer 14 may also have a different composition in the thickness direction. Furthermore, in this case, as the upper anti-reflection layer 14, a single component of Cr and one selected from oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbonitrides of Cr may also be used. Material, or two or more kinds of materials are laminated. The upper anti-reflection layer 14 is described below to set its thickness and the composition ratio (atm%) of Cr, N, C, O, etc., in order to obtain specific optical characteristics and etching rate.

For example, the upper anti-reflective layer 14 is a carbon-nitrogen oxide film containing chromium, oxygen, nitrogen, and carbon. The composition ratio of the upper anti-reflective layer 14 can be set as follows: the chromium content is 25 atm%-50 atm%. Preferably, the content of chromium is 30 atm%～50 atm%, the content of oxygen is 55 atm%～70 atm%, the content of nitrogen is 5 atm%～20 atm%, and the content of carbon is 2 atm% ～5 atm%.

The film thickness of the upper anti-reflection layer 14 can be set according to the required optical characteristics of the upper anti-reflection layer 14 and can be changed according to the composition ratio of Cr, N, C, O, etc. The film thickness of the upper anti-reflection layer 14 can be set to 25.0 nm to 35.0 nm.

Thereby, the reflectance of the upper anti-reflection layer 14 can be set to be less than 5% under the exposure light in the wavelength range of about 365 nm to 436 nm, especially the wavelength of 436 nm.

For the mask layer formed by laminating the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14, the film thickness of the mask layer can be set to 175.0 nm-205.0 nm.

In the mask substrate 10B of this embodiment, regarding both sides of the mask layer formed by laminating the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, the reflection under the exposure light with a wavelength of 436 nm The rates are all set to 5% or less. In addition, the mask layer formed by laminating the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14 can be set so that the optical density becomes 3.0 or more.

Furthermore, in the mask substrate 10B of the present embodiment, by setting the composition ratio of the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14 in the above range, the lower anti-reflection layer 12, the light-shielding layer 13, and the The etching rate of the upper anti-reflective layer 14 is similar to that of the upper anti-reflection layer 14 so that the cross-sectional shape with reduced eaves or flanging can be formed as described below.

In the manufacturing method of the photomask base of this embodiment, after forming the lower anti-reflection layer 12 on the glass substrate (transparent substrate) 11, the light-shielding layer 13 is formed, and thereafter, the upper anti-reflection layer 14 is formed.

In addition to the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14, when the protective layer, the adhesion layer, the anti-chemical corrosion layer, and the etching stop layer are laminated, the manufacturing method of the photomask substrate can be The layer-by-layer steps of the layer-by-layer. As an example, for example, an etching stop layer containing metal silicide can be cited.

Fig. 3 is a cross-sectional view showing the photomask of this embodiment. As shown in FIG. 3, the binary mask (mask) 10 of the present embodiment has a structure formed by patterning a lower anti-reflection layer 12, a light-shielding layer 13, and an upper anti-reflection layer 14 as a mask base 10B. structure.

Hereinafter, the manufacturing method of manufacturing the photomask 10 from the photomask base 10B of this embodiment is demonstrated.

As a step of forming a resist pattern, as shown in FIG. 2, a photoresist layer 15 is formed on the outermost surface of the photomask substrate 10B. Or, a photomask substrate 10B with a photoresist layer 15 formed on the outermost surface can also be prepared in advance. The photoresist layer 15 may be a positive type or a negative type. As the material of the photoresist layer 15, a material that can correspond to the so-called etching of chromium-based materials can be used. As the photoresist layer 15, a liquid resist can be used.

Then, by exposing and developing the photoresist layer 15, a resist pattern is formed on the outer side of the upper anti-reflection layer 14. The resist pattern functions as a mask for etching the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14.

The shape of the resist pattern is appropriately determined according to the etching patterns of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14. As an example, in the light-transmitting area, the resist pattern is set so as to have a shape having an opening width corresponding to the opening width of the light-shielding pattern to be formed.

Next, as an upper anti-reflection pattern forming step, the upper anti-reflection layer 14 is wet-etched with an etchant through the resist pattern to form the upper anti-reflection pattern 14p.

As the etching solution used in the step of forming the upper anti-reflection pattern, an etching solution containing cerium ammonium nitrate can be used. For example, it is preferable to use cerium ammonium nitrate containing acid such as nitric acid or perchloric acid.

Next, as a light-shielding pattern formation step, the light-shielding layer 13 is wet-etched using an etchant via the upper anti-reflection pattern 14p to form the light-shielding pattern 13p.

As the etching solution used in the light-shielding pattern forming step, as in the upper anti-reflection pattern forming step, an etching solution containing cerium ammonium nitrate can be used. For example, it is preferable to use cerium ammonium nitrate containing an acid such as nitric acid or perchloric acid.

Next, as the lower anti-reflection pattern forming step, the lower anti-reflection layer 12 is wet-etched through the patterned light shielding pattern 13p, the upper anti-reflection pattern 14p, and the resist pattern to form the lower anti-reflection pattern 12p.

As the etching solution used in the lower anti-reflection pattern forming step, similar to the upper anti-reflection pattern forming step and the light-shielding pattern forming step, an etching solution containing cerium ammonium nitrate can be used. For example, it is preferable to use cerium ammonium nitrate containing an acid such as nitric acid or perchloric acid.

Furthermore, the mask substrate 10B of the present embodiment can make the lower anti-reflection layer 12, the light-shielding layer 13, and the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14 in the above-mentioned range. And the etching rate of the upper anti-reflective layer 14 is close. Therefore, after forming the upper anti-reflection pattern 14p, the light shielding pattern 13p, and the lower anti-reflection pattern 12p by etching, a good cross-sectional shape close to the vertical can be obtained as the cross-sectional shape of the mask 10.

Furthermore, in the light-shielding pattern forming step, the composition ratio of the light-shielding layer 13 is set to be different from the upper and lower anti-reflection layers 12 and 14 as the above-mentioned range, so the etching rate becomes lower than when no special setting is made. Therefore, compared with the etching in this case, the etching progress of the light-shielding pattern 13p becomes slower. Thereby, the etching rates of the light shielding layer 13, the lower anti-reflection layer 12 and the upper anti-reflection layer 14 can be made close.

That is, the upper anti-reflection pattern 14p, the light shielding pattern 13p, and the lower anti-reflection pattern 12p form an angle (taper angle) θ of the front surface of the glass substrate 11 close to a right angle. For example, the angle θ may be about 90°. In addition, when viewing the glass substrate 11 from the normal direction, the upper anti-reflection pattern 14p, the light shielding pattern 13p, and the lower anti-reflection pattern 12p can all be etched so that they have the same pattern shape.

Furthermore, when a photomask substrate 10B with other films such as an adhesive layer is formed in advance, it is patterned into a patterning with the upper anti-reflection pattern 14p, light-shielding pattern 13p, etc. by wet etching or the like using an etching solution corresponding to the film. And the specific shape corresponding to the lower anti-reflection pattern 12p. The patterning of other films such as the adhesion layer can be performed as a specific step before and after the patterning of the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14 corresponding to the layering sequence thereof.

Furthermore, for the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, the cross-sectional shape after patterning can be improved by varying the oxygen concentration in the film thickness direction. Specifically, regarding the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, that is, the Cr film, the higher the oxygen concentration in the film, the lower the etching rate. Therefore, for the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, by making the oxygen concentration on the upper layer side higher than the oxygen concentration on the lower layer side, the etching rate on the upper layer side can be lower than that on the lower layer side. rate. At the same time, in the film thickness direction, in addition to oxygen, the composition ratio of carbon, nitrogen, or others is changed, thereby enabling the etching rate and optical characteristics to be set to a specific state.

In summary, as shown in FIG. 3, a photomask 10 having an upper anti-reflection pattern 14p, a light shielding pattern 13p, and a lower anti-reflection pattern 12p is obtained.

Hereinafter, the manufacturing method of the photomask substrate of this embodiment will be described based on the drawings.

FIG. 4 is a schematic diagram showing the manufacturing apparatus of the photomask substrate of this embodiment. The mask substrate 10B of this embodiment is manufactured by the manufacturing apparatus shown in FIG. 4.

The manufacturing device S10 shown in FIG. 4 is an interback sputtering device. The manufacturing apparatus S10 has a loading chamber S11, an unloading chamber S16, and a film forming chamber (vacuum processing chamber) S12. The film formation chamber S12 is connected to the loading chamber S11 via a sealing mechanism S17, and is connected to the unloading chamber S16 via a sealing mechanism S18.

The loading chamber S11 is provided with a conveying mechanism S11a for conveying the glass substrate 11 carried in from the outside to the film forming chamber S12, and an exhaust mechanism S11f such as a rotary pump for roughly evacuating the inside of the loading chamber S11.

The unloading chamber S16 is provided with an exhaust mechanism S16f such as a conveying mechanism S16a for conveying the glass substrate 11 after film formation from the film forming chamber S12 to the outside, and a rotary pump for roughly evacuating the inside of the unloading chamber S16.

The film forming chamber S12 is provided with a substrate holding mechanism S12a and three-stage film forming mechanisms S13, S14, and S15 as mechanisms corresponding to the three film forming processes.

The substrate holding mechanism S12a holds the glass substrate 11 such that the glass substrate 11 conveyed by the conveying mechanism S11a faces the targets S13b, S14b, and S15b during film formation. The substrate holding mechanism S12a can carry in and carry out the glass substrate 11 from the loading chamber S11 to the unloading chamber S16.

In the structure of the film forming chamber S12, a film forming mechanism S13 for supplying the film forming material of the first stage among the three film forming mechanisms S13, S14, and S15 is provided at a position near the loading chamber S11. The film forming mechanism S13 has a cathode electrode (backing plate) S13c having a target S13b, and a power supply S13d for applying a sputtering voltage of a negative potential to the backing plate S13c.

The film forming mechanism S13 has: a gas introduction mechanism S13e, which mainly introduces gas into the area near the cathode electrode (backing plate) S13c in the film forming chamber S12; and a high-vacuum exhaust mechanism S13f such as a turbomolecular pump. In the membrane chamber S12, the area near the cathode electrode (backing plate) S13c is highly evacuated.

Furthermore, in the middle of the loading chamber S11 and the unloading chamber S16 of the film forming chamber S12, a film forming mechanism S14 for supplying the film forming material of the second stage among the three film forming mechanisms S13, S14, and S15 is provided. The film forming mechanism S14 has a cathode electrode (backing plate) S14c having a target S14b, and a power supply S14d for applying a sputtering voltage of a negative potential to the backing plate S14c.

The film forming mechanism S14 has: a gas introduction mechanism S14e, which mainly introduces gas into the area near the cathode electrode (backing plate) S14c in the film forming chamber S12; and a high-vacuum exhaust mechanism S14f such as a turbomolecular pump. In the membrane chamber S12, the area near the cathode electrode (backing plate) S14c is highly evacuated.

Furthermore, in the structure of the film forming chamber S12, a film forming mechanism S15 for supplying the film forming material of the third stage among the three film forming mechanisms S13, S14, and S15 is provided at a position near the unloading chamber S16. The film forming mechanism S15 has a cathode electrode (backing plate) S15c having a target S15b, and a power supply S15d for applying a sputtering voltage of a negative potential to the backing plate S15c.

The film forming mechanism S15 has: a gas introduction mechanism S15e, which mainly introduces gas into the area near the cathode electrode (backing plate) S15c in the film forming chamber S12; and a high-vacuum exhaust mechanism S15f such as a turbomolecular pump. In the membrane chamber S12, the area near the cathode electrode (backing plate) S15c is highly evacuated.

In the film forming chamber S12, a gas barrier S12g is provided in the area near the cathode electrodes (backing plates) S13c, S14c, and S15c so that the gas supplied from the gas introduction mechanisms S13e, S14e, and S15e are not mixed into the phase. Adjacent film forming mechanisms S13, S14, and S15 suppress air flow. The gas prevention walls S12g are configured such that the substrate holding mechanism S12a can move between adjacent film forming mechanisms S13, S14, and S15, respectively.

The three-stage film forming mechanisms S13, S14, and S15 respectively have the necessary composition and conditions for sequential film forming on the glass substrate 11 in the film forming chamber S12. In this embodiment, the film forming mechanism S13 corresponds to the film forming of the lower anti-reflection layer 12, the film forming mechanism S14 corresponds to the film forming of the light shielding layer 13, and the film forming mechanism S15 corresponds to the film forming of the upper anti-reflection layer 14.

Specifically, in the film forming mechanism S13, the target S13b includes a material having chromium as a necessary composition for forming the lower anti-reflection layer 12 on the glass substrate 11.

At the same time, in the film forming mechanism S13, as the gas supplied from the gas introducing mechanism S13e, the process gas corresponds to the film formation of the lower anti-reflection layer 12 and contains carbon gas, nitrogen, oxygen, etc., and splashes with argon, nitrogen, etc. The plating gas is set to a specific gas partial pressure and the conditions are set.

In addition, it is exhausted from the high vacuum exhaust mechanism S13f in accordance with the film forming conditions. In addition, in the film forming mechanism S13, the sputtering voltage applied from the power source S13d to the backing plate S13c is set corresponding to the film forming of the lower anti-reflection layer 12.

In addition, in the film forming mechanism S14, the target S14b includes a material having chromium as a necessary composition for forming the light-shielding layer 13 on the lower anti-reflection layer 12.

At the same time, in the film formation mechanism S14, as the gas supplied from the gas introduction mechanism S14e, the process gas corresponds to the film formation of the light-shielding layer 13 and contains carbon gas, nitrogen, oxygen, etc., together with sputtering gases such as argon and nitrogen. Set to a specific gas partial pressure.

In addition, exhaust is performed from the high-vacuum exhaust mechanism S14f in accordance with the film forming conditions. In addition, in the film forming mechanism S14, the sputtering voltage applied from the power source S14d to the backing plate S14c is set corresponding to the film forming of the light shielding layer 13.

In addition, in the film forming mechanism S15, the target S15b includes a material having chromium as a necessary composition for forming the upper anti-reflection layer 14 on the light shielding layer 13.

At the same time, in the film formation mechanism S15, as the gas supplied from the gas introduction mechanism S15e, the process gas corresponds to the film formation of the upper anti-reflection layer 14 and contains carbon gas, nitrogen, oxygen, etc., and is combined with sputtering gases such as argon and nitrogen. Set the conditions for a specific gas partial pressure together.

In addition, exhaust is performed from the high-vacuum exhaust mechanism S15f in accordance with the film forming conditions. In addition, in the film forming mechanism S15, the sputtering voltage applied from the power source S15d to the backing plate S15c is set corresponding to the film forming of the upper antireflection layer 14.

In the manufacturing apparatus S10 shown in FIG. 4, the glass substrate 11 carried in from the loading chamber S11 by the transport mechanism S11a is transported by the substrate holding mechanism S12a in the film forming chamber (vacuum processing chamber) S12 and subjected to three stages of sputtering. membrane. Thereafter, the glass substrate 11 whose film formation has been completed is carried out to the outside from the unloading chamber S16 by the transport mechanism S16a.

In the lower anti-reflection layer forming step, in the film forming mechanism S13, the sputtering gas and the reaction gas are supplied as supply gases from the gas introducing mechanism S13e to the area near the backing plate S13c of the film forming chamber S12. In this state, a sputtering voltage is applied to the backing plate (cathode electrode) S13c from an external power source. In addition, a specific magnetic field can also be formed on the target S13b by a magnetron magnetic circuit.

The ions of the sputtering gas excited by the plasma in the area near the backing plate S13c in the film forming chamber S12 collide with the target S13b of the cathode electrode S13c to cause the particles of the film forming material to fly out. Then, after the flying particles are combined with the reaction gas, they are attached to the glass substrate 11, thereby forming the lower anti-reflection layer 12 on the front surface of the glass substrate 11 with a specific composition.

Similarly, in the light-shielding layer forming step, in the film forming mechanism S14, the sputtering gas and the reaction gas are supplied as supply gases from the gas introducing mechanism S14e to the area near the backing plate S14c of the film forming chamber S12. In this state, a sputtering voltage is applied to the backing plate (cathode electrode) S14c from an external power source. In addition, a specific magnetic field can also be formed on the target S14b by a magnetron magnetic circuit.

The ions of the sputtering gas excited by the plasma in the area near the backing plate S14c in the film forming chamber S12 collide with the target S14b of the cathode electrode S14c to cause the particles of the film forming material to fly out. Then, after the flying particles are combined with the reactive gas, they are attached to the lower anti-reflection layer 12, thereby forming the light-shielding layer 13 with a specific composition on the front surface of the lower anti-reflection layer 12.

Similarly, in the upper anti-reflection layer forming step, in the film forming mechanism S15, the sputtering gas and the reaction gas are supplied as supply gases from the gas introducing mechanism S15e to the area near the backing plate S15c of the film forming chamber S12. In this state, a sputtering voltage is applied to the backing plate (cathode electrode) S15c from an external power source. In addition, a specific magnetic field can also be formed on the target S15b by a magnetron magnetic circuit.

The ions of the sputtering gas excited by the plasma in the area near the backing plate S15c in the film forming chamber S12 collide with the target S15b of the cathode electrode S15c to cause the particles of the film forming material to fly out. Then, after the flying particles are combined with the reaction gas, they are attached to the light shielding layer 13, thereby forming the upper anti-reflection layer 14 with a specific composition on the front surface of the light shielding layer 13.

At this time, in the film formation of the lower anti-reflection layer 12, nitrogen-containing gas, oxygen-containing gas, carbon-containing gas, and sputtering gas at a specific partial pressure are supplied from the gas introduction mechanism S13e to control the partial pressure. The method is switched so that the composition of the lower anti-reflection layer 12 is within the set range.

In addition, during the film formation of the light shielding layer 13, nitrogen-containing gas, oxygen-containing gas, carbon-containing gas, and sputtering gas are supplied to a specific partial pressure from the gas introduction mechanism S14e, and the partial pressure is controlled to switch. , So that the composition of the light-shielding layer 13 is within the set range.

At this time, in the film formation of the upper anti-reflection layer 14, nitrogen-containing gas, oxygen-containing gas, carbon-containing gas, and sputtering gas at a specific partial pressure are supplied from the gas introduction mechanism S15e to control the partial pressure. The method is switched so that the composition of the upper anti-reflection layer 14 is within the set range.

Here, examples of the oxygen-containing gas include CO ₂ (carbon dioxide), O ₂ (oxygen), N ₂ O (nitrous oxide), NO (nitrogen monoxide), CO (carbon monoxide), and the like. In addition, examples of the carbon-containing gas include CO ₂ (carbon dioxide), CH ₄ (methane), C ₂ H ₆ (ethane), CO (carbon monoxide), and the like. Furthermore, in the film formation of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, the targets S13b, S14b, and S15b can also be replaced if necessary.

Furthermore, in addition to the film formation of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14, other films may be laminated. In this case, the target, gas, etc. corresponding to the material of the other film are used as sputtering conditions to form a film by sputtering, or the film is laminated by another film forming method to manufacture the photomask base 10B of this embodiment.

Hereinafter, the film characteristics of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14 of this embodiment will be described.

First, on the glass substrate 11 for forming a mask, a chromium compound film that becomes the main component film of the lower anti-reflection layer 12 is formed by using a sputtering method or the like. The compound film formed at this time is preferably a film containing chromium, oxygen, nitrogen, carbon, etc. By controlling the composition and film thickness of chromium, oxygen, nitrogen, and carbon contained in the film of the lower anti-reflective layer 12, the lower anti-reflective layer 12 having the required optical characteristics and etching rate can be formed. Chromium compounds have strong liquid resistance properties and hydrophobic properties relative to acid or alkaline solutions, so they are suitable for the interface in contact with photoresist.

Next, a chromium compound film to be the light shielding layer 13 is formed using a sputtering method or the like.

Here, when the light-shielding layer 13 is formed of only a chromium compound film and there are no other films, the reflectance is high, about 25%. Therefore, it is desirable to reduce the reflectance by forming the anti-reflection layers 12 and 14 above and below the low-reflection layer due to the front and back surfaces of the light shielding layer 13 being formed.

In this way, by laminating the lower anti-reflection layer 12, the light-shielding layer 13, and the upper anti-reflection layer 14, it is possible to form the material of a chromium compound with strong chemical liquid resistance so that the photomask 10 has the required higher optical Concentration (OD5), and the required etching rate, etc. of the mask layer.

Specifically, as the gas used in the film formation of the lower anti-reflection layer 12 and the upper anti-reflection layer 14, Ar, NO, and CO ₂ can be selected. Here, by _{setting the ratio of NO:CO 2} gas to 1:10 to 10:1, a good cross-sectional shape with less eaves and flanging can be obtained. Furthermore, it can be seen that the reflectance of exposure light with a wavelength of 365 nm to 436 nm can be reduced to 10% or less, especially for exposure light with a wavelength of 436 nm, the reflectance can be reduced to 5% or less.

In addition, it can be seen that the film thicknesses of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14 are respectively set in the ranges of 25.0 nm to 35.0 nm, 125.0 nm to 135.0 nm, and 25.0 nm to 35.0 nm. The mask 10 has the required higher optical density (OD5). [Example]

Next, the composition ratio in the film formation of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14 is verified.

<Example 1> A sputtering method was used to form a chromium compound into a three-layer mask layer on a glass substrate. When forming the chromium compound film to be the light-shielding layer, sputtering is performed by nitrogen gas. When forming the chromium compound film that becomes the upper and lower anti-reflection layers, sputtering is performed by nitrogen gas. _{In addition, CO 2} gas and NO gas were selected as the oxidizing gas, and the partial pressure of each gas was changed. The gas ratio is shown in Table 1.

[Table 1] Example 1 NO: CO ₂ Example 2 NO: CO ₂ Comparative example 1 NO:CO ₂ Comparative example 2 NO:CO ₂ Comparative example 3 NO:CO ₂ Upper anti-reflective layer 69%: 31% 68%: 32% 0%: 100% 0%: 100% 100%:0% Lower anti-reflective layer 66%: 34% 64%: 36% 0%: 100% 65%: 35% 100%:0%

In addition, the film thickness of the lower anti-reflection layer 12, the film thickness of the light-shielding layer 13, the film thickness of the upper anti-reflection layer 14, and the total film thickness of the mask layer are shown in Table 2.

[Table 2] 10 ^-1 nm Example 1 Example 2 Comparative example 1 Comparative example 2 Comparative example 3 Upper anti-reflective layer 320 310 380 350 350 Shading layer 1290 1320 1170 1150 1140 Lower anti-reflective layer 320 320 310 350 380 Mask layer 1930 1950 1860 1850 1870

The changes in the composition ratio of N, O, Cr, and C in each layer of Example 1 were obtained by the Oujie electron spectroscopy method. The results are shown in Table 3.

[table 3] Example 1 [N](%) [O](%) [Cr](%) [C](%) Upper anti-reflective layer 5~13% 56~67% 25~32% 2~4% Shading layer 5~8% - 82~90% - Lower anti-reflective layer 15~19% 38~44% 34~38% 4~5%

In addition, the spectral reflectance of the front surface (upper anti-reflection layer side) corresponding to the wavelength of Example 1 is shown in FIG. 5 and Table 4.

[]Table 4] Front reflection R%(365 nm) R%(405 nm) R%(436 nm) Example 1 6.5% 4.2% 4.6% Example 2 8.2% 4.5% 3.8% Comparative example 1 4.6% 2.8% 3.9% Comparative example 2 5.6% 2.9% 3.3% Comparative example 3 4.1% 4.5% 7.1%

Similarly, the spectral reflectance of the back surface (glass substrate side) corresponding to the wavelength of Example 1 is shown in FIG. 6 and Table 5.

[table 5] Back reflection R%(365 nm) R%(405 nm) R%(436 nm) Example 1 6.7% 4.7% 4.4% Example 2 8.2% 5.6% 4.6% Comparative example 1 6.4% 10.7% 15.3% Comparative example 2 7.9% 5.6% 4.4% Comparative example 3 5.3% 8.7% 12.6%

According to these results, in Example 1, the reflectivity of the front and back surfaces under the exposure light with a wavelength of 365 nm to 436 nm is 10% or less, especially for the exposure light with a wavelength of 436 nm, the reflectivity becomes 5 %the following.

<Example 2> Sputtering was used to form a chromium compound into a three-layer mask layer on a glass substrate. When forming the chromium compound film to be the light-shielding layer, sputtering is performed by nitrogen gas. When forming the chromium compound film that becomes the upper and lower anti-reflection layers, sputtering is performed by nitrogen gas. In addition, CO ₂ gas and NO gas were selected as the oxidizing gas, and the partial pressure of each gas was changed. The gas ratio is shown in Table 1.

In addition, the film thickness of the lower anti-reflection layer 12, the film thickness of the light-shielding layer 13, the film thickness of the upper anti-reflection layer 14, and the total film thickness of the mask layer are shown in Table 2.

The changes in the composition ratio of N, O, Cr, and C in each layer of Example 2 were obtained by the Oujie electron spectroscopy method. The results are shown in Table 6.

[Table 6] Example 2 [N](%) [O](%) [Cr](%) [C](%) Upper anti-reflective layer 5~12% 55~68% 25~30% 2~4% Shading layer 5~8% - 78~85% 7~11% Lower anti-reflective layer 15～20% 39~44% 32~37% 3~5%

In addition, the spectral reflectance of the front surface (upper anti-reflection layer side) corresponding to the wavelength of Example 2 is shown in FIG. 5 and Table 4.

Similarly, the spectral reflectance of the back surface (glass substrate side) corresponding to the wavelength of Example 2 is shown in FIG. 6 and Table 5.

According to these results, in Example 2, the reflectivity of the front and back surfaces under the exposure light with a wavelength of 365 nm to 436 nm is 10% or less, especially for the exposure light with a wavelength of 436 nm, the reflectivity becomes 5 %the following.

<Comparative Examples 1 to 3> In the same manner as in the above-mentioned Example 1, a chromium compound to be a three-layer mask layer was formed by a sputtering method. In Comparative Examples 1 and 3, when forming the chromium compound film to be the light-shielding layer, sputtering was performed with argon gas and nitrogen gas. In Comparative Example 2, when the chromium compound film used as the light shielding layer was formed, sputtering was performed with nitrogen, argon, and methane gas. When forming the chromium compound that becomes the upper and lower anti-reflection layers, sputtering is performed by nitrogen gas. _{In addition, CO 2} gas and NO gas were selected as the oxidizing gas, and the partial pressure of each gas was changed. The gas ratio is shown in Table 1.

In addition, the film thicknesses of the lower anti-reflection layer 12, the light shielding layer 13, the upper anti-reflection layer 14 and the total film thickness of the mask layer are shown in Table 2. The changes in the composition ratios of N, O, Cr, and C in each layer of Comparative Examples 1 to 3 were obtained by Ojie electron spectroscopy. The results are shown in Tables 7 to 9.

[Table 7] Comparative example 1 [N](%) [O](%) [Cr](%) [C](%) Upper anti-reflective layer 9~13% 48~58% 28~33% 5~7% Shading layer 11~16% - 77~82% - Lower anti-reflective layer 11~16% 42-49% 33~37% 5~7%

[Table 8] Comparative example 2 [N](%) [O](%) [Cr](%) [C](%) Upper anti-reflective layer 9~14% 49~59% 28~32% 4~6% Shading layer 13~15% - 72~77% 5~10% Lower anti-reflective layer 14~23% 33~46% 37~45% 2~8%

[Table 9] Comparative example 3 [N](%) [O](%) [Cr](%) [C](%) Upper anti-reflective layer 4~8% 63~70% 25~28% 1~2% Shading layer 11~15% - 73~82% - Lower anti-reflective layer 7~10% 55~60% 31~34% 1~2%

Furthermore, the spectral reflectance of the front surface (upper anti-reflection layer side) corresponding to the wavelengths of Comparative Examples 1 to 3 is shown in FIG. 5 and Table 4.

Similarly, the spectral reflectance of the back surface (glass substrate side) corresponding to the wavelength of Comparative Examples 1 to 3 is shown in FIG. 6 and Table 5.

According to these results, in Comparative Examples 1 to 3, the reflectance under the exposure light with a front wavelength of 365 nm to 436 nm is less than 10%. In Comparative Example 2, the reflectance at the back side of exposure with a wavelength of 365 nm to 436 nm is less than 10%. The reflectivity under light becomes 10% or less. However, it can be seen that in Comparative Examples 1 and 3, the reflectance of the back surface does not become 10% or less.

The gas composition ratio in the film of each layer must be greatly changed according to the purpose of the light-shielding layer and the anti-reflection layer. In order to obtain a higher optical density (for example, OD5), the light-shielding layer must reduce oxidizing gas. In addition, in order to reduce the reflectivity of the anti-reflection layer, it is necessary to introduce a large amount of oxidizing gas into the film. Therefore, in the light-shielding layer and the anti-reflection layer, the gas composition ratio in the film becomes larger, resulting in a difference in etching rate.

Next, the etching shapes in the film formation of the lower anti-reflection layer 12, the light shielding layer 13, and the upper anti-reflection layer 14 are verified.

<Example 1> The mask substrate produced in Example 1 was patterned (resist coating, exposure, development, and etching), and its cross-sectional shape was observed by SEM. The results are shown in Fig. 7. In addition, a plan view of the patterned boundary is shown in FIG. 12. Furthermore, the magnification in Figure 7 is 80,000 times. The magnification in Figure 12 is 30,000 times.

As a result, in Experimental Example 1, the eaves (the length of the upper anti-reflective layer protruding from the light-shielding layer): 50 nm, and the flanging (the length of the lower anti-reflective layer protruding from the light-shielding layer): 59 nm.

<Example 2> The mask substrate produced in Example 2 was patterned (resist coating, exposure, development, and etching), and its cross-sectional shape was observed by SEM. The results are shown in Fig. 8. In addition, a plan view of the patterned boundary is shown in FIG. 13. Furthermore, the magnification in Figure 8 is 80,000 times. The magnification in Figure 13 is 30,000 times.

As a result, in Experimental Example 2, the eaves (the length of the upper anti-reflective layer protruding from the light-shielding layer): 57 nm, and the flanging (the length of the lower anti-reflective layer protruding from the light-shielding layer): 40 nm.

<Comparative example 1> As in Example 1, the produced photomask substrate was patterned (resist coating, exposure, development, and etching), and its cross-sectional shape was observed by SEM. The results are shown in Fig. 9. In addition, a plan view of the patterned boundary is shown in FIG. 14. Furthermore, the magnification in Figure 9 is 80,000 times. The magnification in Figure 14 is 30,000 times.

As a result, in Comparative Example 1, the eaves (the length of the upper anti-reflective layer protruding from the light-shielding layer) was 79 nm, and the flanging (the length of the lower anti-reflective layer protruding from the light-shielding layer) was 145 nm.

＜Comparative example 2＞ As in Example 1, the produced photomask substrate was patterned (resist coating, exposure, development, and etching), and its cross-sectional shape was observed by SEM. The results are shown in Fig. 10. In addition, a plan view of the patterned boundary is shown in FIG. 15. Furthermore, the magnification in Figure 10 is 80,000 times. The magnification in Figure 15 is 30,000 times.

As a result, in Comparative Example 2, the eaves (the length of the upper anti-reflective layer protruding from the light-shielding layer): 140 nm, and the flanging (the length of the lower anti-reflective layer protruding from the light-shielding layer): 52 nm.

＜Comparative example 3＞ As in Example 1, the produced photomask substrate was patterned (resist coating, exposure, development, and etching), and its cross-sectional shape was observed by SEM. The results are shown in Fig. 11. In addition, a plan view of the patterned boundary is shown in FIG. 16. Furthermore, the magnification in Figure 11 is 80,000 times. The magnification in Figure 16 is 30,000 times.

As a result, in Comparative Example 3, the eaves (the length of the upper anti-reflection layer projecting from the light-shielding layer) was 128 nm, and the flanging (the length of the lower anti-reflection layer projecting from the light-shielding layer) was 154 nm.

According to these results, it can be confirmed that in Comparative Examples 1 to 3, compared with the light shielding layer, the anti-reflection layer on the side of the glass layer (back) and the anti-reflection layer on the upper side (front) are in a protruding shape (the upper layer is the eaves Shape, the lower layer is the flanging shape). This is due to the poor etching rate between the anti-reflection layer and the light-shielding layer. It can be seen that the photomask substrate of the present invention can form a good cross-sectional shape, and can manufacture high-definition photomasks.

10: Mask 10B: Mask base 11: Glass substrate (transparent substrate) 12: Lower anti-reflection layer 12p: lower anti-reflection pattern 13: shading layer 13p: shading pattern 14: Upper anti-reflective layer 14p: upper anti-reflective pattern 15: photoresist layer S10: Manufacturing device S11: Loading room S11a: Transport mechanism S11f: Exhaust mechanism S12: Film forming chamber S12a: Substrate holding mechanism S12g: Anti-gas wall S13: Film forming mechanism S13b: target S13c: Cathode electrode S13d: power supply S13e: Gas introduction mechanism S13f: High vacuum exhaust mechanism S14: Film forming mechanism S14b: target S14c: Cathode electrode S14d: power supply S14e: Gas introduction mechanism S14f: High vacuum exhaust mechanism S15: Film forming mechanism S15b: target S15c: Cathode electrode S15d: power supply S15e: Gas introduction mechanism S15f: High vacuum exhaust mechanism S16: Unloading room S16a: Transport mechanism S16f: Exhaust mechanism S17: Closed mechanism S18: Closed mechanism

FIG. 1 is a cross-sectional view showing a mask substrate according to the first embodiment of the present invention. Fig. 2 is a cross-sectional view showing the mask substrate of the first embodiment of the present invention. Fig. 3 is a cross-sectional view showing the photomask of the first embodiment of the present invention. FIG. 4 is a schematic diagram showing a photomask substrate and a film forming apparatus in the manufacturing method of the photomask according to the first embodiment of the present invention. FIG. 5 is a graph showing the front side spectral reflectance of the embodiment and the comparative example of the mask substrate of the present invention. Fig. 6 is a graph showing the back spectroscopic reflectance of the embodiment and the comparative example of the mask substrate of the present invention. FIG. 7 is an SEM photograph showing the cross-sectional shape of the photomask substrate of Example 1 of the present invention after patterning. FIG. 8 is an SEM photograph showing the cross-sectional shape after patterning of Example 2 of the photomask substrate of the present invention. FIG. 9 is an SEM photograph showing the cross-sectional shape of Comparative Example 1 of the photomask substrate of the present invention after patterning. FIG. 10 is an SEM photograph showing the cross-sectional shape of Comparative Example 2 of the photomask substrate of the present invention after patterning. FIG. 11 is an SEM photograph showing the cross-sectional shape of Comparative Example 3 of the photomask substrate of the present invention after patterning. 12 is a top view SEM photograph showing the patterned shape of Experimental Example 1 of the mask substrate of the present invention. FIG. 13 is a top view SEM photograph showing the patterned shape of Experimental Example 2 of the mask substrate of the present invention. 14 is a top-view SEM photograph showing the patterned shape of Comparative Example 1 of the photomask substrate of the present invention. FIG. 15 is a top view SEM photograph showing the patterned shape of Comparative Example 2 of the photomask substrate of the present invention. FIG. 16 is a top view SEM photograph showing the patterned shape of Comparative Example 3 of the photomask substrate of the present invention.

10B: Mask base

11: Glass substrate (transparent substrate)

12: Lower anti-reflection layer

13: shading layer

14: Upper anti-reflective layer

Claims (9)

A photomask substrate, which has a mask layer that becomes a photomask, The above mask layer has: The lower anti-reflection layer is laminated on the transparent substrate; The light-shielding layer is arranged at a position farther away from the transparent substrate than the lower anti-reflection layer; and The upper anti-reflection layer is arranged at a position farther away from the transparent substrate than the light shielding layer; and The lower anti-reflective layer contains chromium, oxygen, nitrogen, and carbon oxynitride film, the content of chromium contained in the lower anti-reflective layer is 25 atm%-50 atm%, and the oxygen contained in the lower anti-reflective layer The content rate is 30 atm%～50 atm%, the nitrogen content contained in the lower anti-reflection layer is 10 atm%～30 atm%, and the carbon content contained in the lower anti-reflection layer is 2 atm%～ 5 atm%, The light-shielding layer includes a nitride film of chromium and nitrogen, the content of chromium in the light-shielding layer is 70 atm% to 95 atm%, and the nitrogen content is 5 atm% to 20 atm%, The upper anti-reflection layer contains chromium, oxygen, nitrogen, and carbon oxynitride film. The content of chromium contained in the upper anti-reflection layer is 25 atm%-50 atm%, and the oxygen contained in the upper anti-reflection layer The content rate is 55 atm%～70 atm%, the nitrogen content contained in the upper anti-reflection layer is 5 atm%～20 atm%, and the carbon content contained in the upper anti-reflection layer is 2 atm%～ 5 atm%. A photomask substrate, which has a mask layer that becomes a photomask, The above mask layer has: The lower anti-reflection layer is laminated on the transparent substrate; The light-shielding layer is arranged at a position farther away from the transparent substrate than the lower anti-reflection layer; and The upper anti-reflection layer is arranged at a position farther away from the transparent substrate than the light shielding layer; and The lower anti-reflective layer contains chromium, oxygen, nitrogen, and carbon oxynitride film, the content of chromium contained in the lower anti-reflective layer is 25 atm%-50 atm%, and the oxygen contained in the lower anti-reflective layer The content rate is 30 atm%～50 atm%, the nitrogen content contained in the lower anti-reflection layer is 10 atm%～30 atm%, and the carbon content contained in the lower anti-reflection layer is 2 atm%～ 5 atm%, The light-shielding layer contains a carbonitride film of chromium, nitrogen and carbon, the content of chromium in the light-shielding layer is 70 atm%～95 atm%, and the content of nitrogen in the light-shielding layer is 5 atm%～ 20 atm%, the carbon content of the above-mentioned light-shielding layer is 0 atm%～15 atm%, The upper anti-reflection layer contains chromium, oxygen, nitrogen, and carbon oxynitride film. The content of chromium contained in the upper anti-reflection layer is 25 atm%-50 atm%, and the oxygen contained in the upper anti-reflection layer The content rate is 55 atm%～70 atm%, the nitrogen content contained in the upper anti-reflection layer is 5 atm%～20 atm%, and the carbon content contained in the upper anti-reflection layer is 2 atm%～ 5 atm%. Such as the photomask substrate of claim 1 or 2, in which the reflectivity of both sides of the above-mentioned mask layer under exposure light with a wavelength of 365 nm to 436 nm is less than 10%. Such as the photomask substrate of claim 3, in which the reflectivity of both sides of the above-mentioned mask layer under exposure light with a wavelength of 436 nm is less than 5%. The photomask substrate of claim 1 or 2, wherein the film thickness of the lower anti-reflection layer, the film thickness of the light-shielding layer, and the thickness of the upper anti-reflection layer are set in the mask layer so that the optical density becomes 3.0 or more Film thickness. Such as the photomask substrate of claim 5, wherein the film thickness of the lower anti-reflection layer is 25.0 nm to 35.0 nm, The film thickness of the above-mentioned light-shielding layer is 125.0 nm ~ 135.0 nm, The film thickness of the upper anti-reflection layer is 25.0 nm to 35.0 nm. Such as the photomask substrate of claim 6, wherein the film thickness of the mask layer is 175.0 nm-205.0 nm. Such as the photomask substrate of claim 1, which has a photoresist layer disposed at a position farther away from the transparent substrate than the mask layer. A photomask manufactured from the photomask substrate of any one of claims 1 to 8.

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