TW201937268A - Phase shift mask blank, method of manufacturing phase shift mask and method of manufacturing display device having a high transmittance capable of patterning a phase shift film in a cross-sectional shape - Google Patents

Abstract

The present invention provides a phase shift mask substrate which can pattern a phase shift film into a cross-sectional shape which can sufficiently exhibit a phase shift effect and has a high transmittance.
The phase shift mask substrate of the present invention is characterized in that it has a phase shift film on a transparent substrate, and has an etching mask film on the phase shift film, and the phase shift mask base is a master plate for forming a phase on the transparent substrate by wet etching the etched film pattern by forming the etch mask film into a desired pattern as a mask The phase shift mask of the offset film pattern, wherein the phase shift film contains a transition metal, ruthenium, and oxygen, and the oxygen content is 510 atom% or more and 70 atom% or less, and the region is 10 nm or more from the interface to the depth. The content ratio of oxygen to hydrazine is 3.0 or less.

Description

Phase shift mask base, method of manufacturing phase shift mask, and method of manufacturing display device

The present invention relates to a phase shift mask substrate, a method of manufacturing a phase shift mask using the same, and a method of manufacturing a display device.

In recent years, in display devices such as FPD (Flat Panel Display), which are represented by LCD (Liquid Crystal Display), high-definition and high-speed display are also associated with high screen size and wide viewing angle. development of. One of the elements necessary for such high-definition and high-speed display is to produce a circuit pattern such as a component and a wiring which are fine and high in dimensional accuracy. The display device uses a pattern of circuits to use light lithography. Therefore, there is a need for a phase shift mask for manufacturing a display device having a fine and highly precise pattern.

For example, Patent Document 1 discloses a base mask for a flat panel display and a photomask for use in the case where the base mask for a flat panel display is subjected to wet etching of a film containing molybdenum molybdenum, in order to make the transparent substrate The damage is minimized, and the film containing molybdenum molybdenum is wet-etched by an etching solution obtained by diluting phosphoric acid, hydrogen peroxide, or ammonium fluoride with water.
Further, Patent Document 2 discloses a phase inversion base mask and a photomask for the purpose of improving the precision of the pattern, and the phase inversion film 104 includes etching by the same etching solution. The films having different compositions are formed in the form of a multilayer film or a continuous film in which at least two or more layers of the films of different compositions are laminated one or more times.
[Previous Technical Literature]
[Patent Literature]

[Patent Document 1] Korean Patent Application Publication No. 10-2016-0024204
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2017-167512

[The problem that the invention wants to solve]

In recent years, as a phase shift mask substrate for manufacturing such a display device, in order to reliably transfer a fine pattern of less than 2.0 μm, it is considered that the transmittance of light having a phase shift film with respect to exposure is 10% or more. Further, a phase shift film having an optical property of 20% or more is used as a phase shift film containing oxygen in a ratio of a predetermined ratio or more (5 atom% or more, further 10 atom% or more). However, it has been found that when the phase shift film having an oxygen content of 5 atom% or more and further 10 atom% or more is patterned by wet etching, the wet etching liquid penetrates into the phase shift. The etching of the interface portion is performed relatively quickly at the interface of the film with the etch mask formed thereon. The cross-sectional shape of the edge portion of the formed phase-shifted film pattern is gradiented to have a tapered shape with a hem.

In the case where the cross-sectional shape of the edge portion of the phase shift film pattern is a tapered shape, the phase shift effect becomes smaller as the film thickness of the edge portion of the phase shift film pattern decreases. Therefore, the phase shift effect cannot be sufficiently exerted, and the fine pattern of less than 2.0 μm cannot be stably transferred. When the oxygen content in the phase shift film is 5 atom% or more and further 10 atom% or more, it is difficult to strictly control the cross-sectional shape of the edge portion of the phase shift film pattern, and it is very difficult to control the line width (CD). .

Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a phase shift in which a phase shift film can be patterned by wet etching into a cross-sectional shape in which a phase shift effect can be sufficiently exhibited. A method of manufacturing a shift mask substrate, a phase shift mask having a phase shift film pattern capable of exhibiting a phase shift effect, and a method of manufacturing a display device using the phase shift mask.
[Technical means to solve the problem]

In order to solve such problems, the inventors of the present invention have conducted intensive studies on a method of making the cross-sectional shape of the edge portion of the phase shift film pattern vertical. The state of the interface between the phase shift film containing transition metal, ruthenium and oxygen and the etching mask film was investigated and discussed. It was found that the transition metal between the phase offset film and the etch mask film existed. An important cause of oxide infiltration. Further, the present inventors further studied and found that a region including a ratio of oxygen in a composition gradient region formed at an interface with the phase shift film is gradually and/or continuously increased in the depth direction, and is spread over the above phase. When the interface between the offset film and the etching mask film is at a depth of 10 nm, and the phase shift film and the etching mask film are formed so that the oxygen content ratio with respect to 矽 is 3.0 or less, the transition metal existing at the interface can be suppressed. The oxide is such that it inhibits penetration at the interface. The present invention has been completed as described above, and has the following constitution.

(Configuration 1) A phase shift mask substrate characterized in that it has a phase shift film on a transparent substrate, and has an etching mask film on the phase shift film, and the phase shift mask is a base master for forming a mask by forming an etch mask pattern having a desired pattern on the etch mask film as a mask, and performing wet etching on the phase shift film to form the transparent layer a phase shift mask having a phase offset film pattern on the substrate,
The phase shift film contains a transition metal, ruthenium, and oxygen, and the oxygen content is 5 atom% or more and 70 atom% or less.
Forming a gradient region at an interface between the phase shifting film and the etching mask film, wherein the composition gradient region includes a region in which the ratio of the oxygen increases stepwise and/or continuously toward the depth direction.
The content ratio of oxygen to cerium is 3.0 or less over the interface between the phase shifting film and the etch mask film to a depth of 10 nm.

(Configuration 2) The phase shift mask substrate according to the first aspect, wherein the phase shift film comprises a plurality of layers.

(Configuration 3) The phase shift mask substrate according to the first aspect, wherein the phase shift film comprises a single layer.

The phase shift mask substrate according to any one of the first to third aspect, wherein the phase shift film contains nitrogen.

The phase shift mask base according to any one of the first to fourth aspects, wherein the phase shift film has a nitrogen content of 2 atom% or more and 60 atom% or less.

The phase shift mask substrate according to any one of the first to fifth aspect, wherein the phase shift film has a film stress of 0.2 GPa or more and 0.8 GPa or less.

The phase shift mask substrate according to any one of the first to sixth aspect, wherein the etching mask film comprises a chromium-based material.

The phase shift mask substrate according to any one of the first to seventh aspect, wherein the etching mask film contains at least one of nitrogen, oxygen, and carbon.

The phase shift mask substrate according to any one of the first to eighth aspect, wherein the transparent substrate is a rectangular substrate, and a short side of the transparent substrate has a length of 300 mm or more.

(Configuration 10) A method of manufacturing a phase shift mask, comprising the steps of: preparing a phase shift mask substrate according to any one of Embodiments 1 to 9;
Forming a resist film on the phase shift mask substrate;
A resist film pattern is formed by drawing a desired pattern on the resist film, and the resist film pattern is used as a mask, and the etching mask film is patterned by wet etching to form And etching the mask film pattern; and forming the phase shift film pattern on the transparent substrate by wet etching the phase shift film by using the etching mask pattern as a mask.

(Configuration 11) A method of manufacturing a display device, comprising the steps of: using a phase shift mask manufactured by using the phase shift mask substrate according to any one of Embodiments 1 to 9, or using The phase shift mask manufactured by the method for manufacturing a phase shift mask of the tenth embodiment is configured to expose and transfer a transfer pattern to a resist film on a display device.
[Effects of the Invention]

According to the phase shift mask substrate of the present invention, a phase shift mask substrate which can be patterned by wet etching into a cross-sectional shape which can sufficiently exhibit a phase shift effect and has a high transmittance can be obtained. Further, a phase shift mask substrate which can be patterned by wet etching into a cross-sectional shape having a small CD deviation can be obtained.

Further, according to the method of manufacturing a phase shift mask of the present invention, the phase shift mask can be manufactured using the phase shift mask substrate. Therefore, a phase shift mask having a phase shift film pattern that can sufficiently exert the phase shift effect can be manufactured. Further, a phase shift mask having a phase shift film pattern having a small CD deviation can be manufactured. The phase shift mask can cope with the miniaturization of the line and gap patterns or contact holes.

Further, according to the method of manufacturing a display device of the present invention, a phase shift mask manufactured using the phase shift mask substrate or a phase shift mask manufactured by the phase shift mask manufacturing method can be used. Display device. Therefore, a display device having a fine line and gap pattern or contact hole can be manufactured.

Embodiment 1.
In the first embodiment, the phase shift mask base will be described. The phase shift mask base is used for wet etching the phase shift film by using the etch mask film pattern to form a desired pattern by etching the mask film as a mask. A phase shift mask having a phase offset film pattern formed on a transparent substrate.

Fig. 1 is a schematic view showing the film constitution of the phase shift mask substrate 10.
The phase shift mask substrate 10 shown in FIG. 1 includes a transparent substrate 20, a phase shift film 30 formed on the transparent substrate 20, and an etching mask film 40 formed on the phase shift film 30.

The transparent substrate 20 is transparent with respect to the exposed light. When the transparent substrate 20 is set to have no surface reflection loss, it has a transmittance of 85% or more with respect to the light to be exposed, and preferably a transmittance of 90% or more. The transparent substrate 20 contains a material containing barium and oxygen, and may include a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, or low thermal expansion glass (SiO ₂ —TiO ₂ glass, etc.). In the case where the transparent substrate 20 includes a low thermal expansion glass, the positional change of the phase shift film pattern caused by the thermal deformation of the transparent substrate 20 can be suppressed. Further, the transparent substrate 20 for a phase shift mask base used for a display device is generally a rectangular substrate, and the short side of the transparent substrate has a length of 300 mm or more. According to the present invention, it is possible to stably transfer a phase shift of a fine phase shift film pattern of, for example, less than 2.0 μm formed on a transparent substrate even if the short side of the transparent substrate has a length of 300 mm or more. The phase of the reticle is offset from the reticle substrate.

The phase shift film 30 contains a transition metal telluride-based material containing a transition metal, ruthenium, and oxygen. As the transition metal, molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), zirconium (Zr) or the like is preferable. Further, the phase shift film 30 may also contain nitrogen. If nitrogen is contained, the refractive index is increased, so that it is preferable to use a film thickness to obtain a phase difference. Further, when the content ratio of nitrogen contained in the phase shift film 30 is increased, the absorption coefficient of the complex refractive index becomes large, and a high transmittance cannot be achieved. The content of nitrogen contained in the phase shift film 30 is preferably 2 atom% or more and 60 atom% or less. More preferably, it is 2 atom% or more and 50 atom% or less, More preferably, it is 5 atom% or more and 30 atom% or less.
Examples of the transition metal halide-based material include an oxide of a transition metal halide, a nitrogen oxide of a transition metal halide, a carbon oxide of a transition metal halide, and a carbon oxynitride of a transition metal halide. Further, in terms of obtaining an excellent pattern cross-sectional shape by wet etching, the transition metal telluride-based material is preferably a molybdenum-based molybdenum-based material (MoSi-based material) or a zirconium-hydride-based zirconium-based material (ZrSi-based material). Molybdenum zirconium-based material (MoZrSi-based material).
The phase shift film 30 has a function of adjusting the reflectance of light incident on the side from the transparent substrate 20 (hereinafter, referred to as back surface reflectance), and a function of adjusting the transmittance and phase difference with respect to the light to be exposed.
The phase shift film 30 can be formed by a sputtering method.

The transmittance of the phase shift film 30 with respect to the exposed light satisfies the value necessary for the phase shift film 30. The transmittance of the phase shift film 30 is preferably 10% to 70%, more preferably 15% to 65%, with respect to the light of a specific wavelength (hereinafter referred to as a representative wavelength) included in the light to be exposed. It is preferably 20% to 60%. That is, when the light to be exposed is a composite light including light in a wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-described transmittance with respect to light of a representative wavelength included in the wavelength range. For example, when the light to be exposed is a composite light including i-rays, h-rays, and g-rays, the phase shift film 30 has the above-described transmittance with respect to any of the i-rays, the h-rays, and the g-rays.
The transmittance of the phase shift film 30 can be adjusted by the atomic ratio of the transition metal to the yttrium contained in the phase shift film 30. In order to set the transmittance of the phase shift film 30 to the above transmittance, the atomic ratio of the transition metal to ruthenium is set to be 1:1 or more and 1:15 or less. In order to improve the chemical resistance (wash resistance) of the phase shift film 30, the atomic ratio of the transition metal to ruthenium is preferably 1:2 or more and 1:15 or less, and more preferably 1:4 or more and 1:10. The following is more desirable.
The transmittance can be measured using a phase shift amount measuring device or the like.

The phase difference of the phase shift film 30 with respect to the exposed light satisfies the value necessary as the phase shift film 30. The phase difference of the phase shift film 30 is preferably 160 to 200, more preferably 170 to 190 with respect to the light of the representative wavelength included in the exposed light. By this property, the phase of the light of the representative wavelength included in the exposed light can be changed to 160 to 200. Therefore, a phase difference of 160° to 200° is generated between the light of the representative wavelength transmitted through the phase shift film 30 and the light of the representative wavelength transmitted only through the transparent substrate 20. That is, when the light to be exposed is a composite light including light in a wavelength range of 313 nm or more and 436 nm or less, the phase shift film 30 has the above-described phase difference for the light of the representative wavelength included in the wavelength range. For example, when the light to be exposed is a composite light including i-rays, h-rays, and g-rays, the phase shift film 30 has the above-described phase difference with respect to any of the i-rays, the h-rays, and the g-rays.
The phase difference can be measured using a phase shift amount measuring device or the like.

The back surface reflectance of the phase shift film 30 is 15% or less, preferably 10% or less, in the wavelength region of 365 nm to 436 nm. Further, when the back surface reflectance of the phase shift film 30 is such that the exposed light contains j-rays, the light in the wavelength region of 313 nm to 436 nm is preferably 20% or less, more preferably 17% or less. Further preferably, it is preferably 15% or less. Further, the back surface reflectance of the phase shift film 30 is 0.2% or more in the wavelength region of 365 nm to 436 nm, and the light in the wavelength region of 313 nm to 436 nm is preferably 0.2% or more.
The back reflectance can be measured using a spectrophotometer or the like.

The phase shift film 30 is set to have the above-described phase difference and transmittance, and the oxygen content of the phase shift film 30 is adjusted so that the phase shift film 30 becomes the back surface reflectance as necessary. Specifically, the phase shift film 30 is configured such that the oxygen content is 5 atom% or more and 70 atom% or less. The oxygen content of the phase shift film 30 is preferably 10 atom% or more and 70 atom% or less. The phase shift film 30 may include a plurality of layers or a single layer. The phase shift film 30 including a single layer is preferable in that it is difficult to form an interface in the phase shift film 30 and it is easy to control the cross-sectional shape. On the other hand, the phase shift film 30 including a plurality of layers is preferable in terms of easiness of film formation and the like.
Further, the light element of nitrogen and oxygen contained in the phase shift film 30 may be uniformly contained in the film thickness direction of the phase shift film 30, or may be increased or decreased stepwise or continuously. In addition, it is preferable that the nitrogen content rate and the oxygen content rate are the specific content ratio in a region of 50% or more of the film thickness of the phase shift film 30.
Further, the phase shift film 30 of the phase shift mask substrate 10 is required to have high drug resistance (wash resistance). In order to improve the chemical resistance (wash resistance) of the phase shift film 30, it is effective to increase the film density. The film density of the phase shift film 30 is related to the film stress, and the film stress of the phase shift film 30 is preferably high in view of chemical resistance (wash resistance). On the other hand, regarding the film stress of the phase shift film 30, it is necessary to consider the misalignment when forming the phase shift film pattern and the loss of the phase shift film pattern. From the above viewpoints, the film stress of the phase shift film 30 is preferably 0.2 GPa or more and 0.8 GPa or less, and more preferably 0.4 GPa or more and 0.8 GPa or less.

The etching mask film 40 is disposed on the upper side of the phase shift film 30, and includes a material having etching resistance to the etching liquid which etches the phase shift film 30. Further, the etching mask film 40 may have a function of blocking the transmission of the light to be exposed, and may further have a function of causing the phase shift film 30 to be incident on the light from the side of the phase shift film 30. The film surface reflectance is reduced by 15% or less in the wavelength region of 350 nm to 436 nm. The etch mask film 40 contains, for example, a chrome-based material. More specifically, the chromium-based material includes a material containing at least one of chromium (Cr), chromium (Cr), oxygen (O), nitrogen (N), and carbon (C). Alternatively, a material containing at least one of chromium (Cr) and oxygen (O), nitrogen (N), and carbon (C), and further containing fluorine (F) may be mentioned. For example, examples of the material constituting the etching mask film 40 include Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF.
The etch mask film 40 can be formed by a sputtering method.

In the case where the etching mask film 40 has a function of blocking the transmission of the light to be exposed, the optical layer having a thickness of the portion of the phase shift film 30 and the etching mask film 40 is preferably 3 or more. More preferably, it is 3.5 or more, More preferably, it is 4 or more.
The optical density can be measured using a spectrophotometer or an OD (Optical Density) meter or the like.

The etch mask film 40 may include a single layer film having a uniform composition depending on its function, or may include a plurality of layers of films having different compositions, or may comprise a single layer film having a composition continuously varying in the thickness direction.

Further, the phase shift mask substrate 10 shown in FIG. 1 is provided with an etching mask film 40 on the phase shift film 30, but an etching mask film 40 is provided on the phase shift film 30, and the etching mask is provided. The present invention can also be applied to a film 40 having a phase shift mask substrate having a resist film.

Moreover, the phase shift mask substrate 10 is formed with a composition gradient region at the interface between the phase shift film 30 and the etch mask film 40, and the ratio of oxygen contained in the composition gradient region is stepwise toward the depth direction and/or The way of continuously increasing the area. More specifically, in the composition gradient region, at least in the depth direction from the interface between the phase shift film 30 and the etching mask film 40 toward the transparent substrate 20 side, the ratio of oxygen is stepwise and/or continuously Increased area.
Further, the phase shift mask substrate 10 is formed over the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm, and the oxygen-to-tantalum content ratio is 3.0 or less. The interface is set to a position where the ratio of the transition metal is reduced from the phase shift film 30 toward the etch mask film 40 and the transition metal is formed when the phase shift mask substrate 10 is subjected to composition analysis by X-ray photoelectron spectroscopy. The content rate became the position of 0 atom% for the first time.
The ratio of oxygen to yttrium is required to be 3.0 or less, preferably 2.8 or less, more preferably 2.5 or less, and more preferably in the region of the interface between the phase shift film 30 and the etch mask 40 to a depth of 10 nm. 2.0 or less is ideal. Further, from the viewpoint of the film continuity of the phase shift film 30 and the composition gradient region, the content ratio of the oxygen to the ruthenium is preferably 0.3 or more, and more preferably 0.5 or more.

Next, a method of manufacturing the phase shift mask substrate 10 of the embodiment will be described. The phase shift mask substrate 10 shown in Fig. 1 is manufactured by performing the following phase shift film forming step and etching mask processing step.
Hereinafter, each step will be described in detail.

1. Phase Offset Film Forming Step First, the transparent substrate 20 is prepared. The transparent substrate 20 may be any glass material including synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ —TiO ₂ glass, etc.) as long as it is transparent to the exposed light. By.

Next, the phase shift film 30 is formed on the transparent substrate 20 by sputtering.
The film formation of the phase shift film 30 is a sputtering palladium containing a transition metal and a ruthenium which is a main component of a material constituting the phase shift film 30, or a sputtering palladium containing a transition metal, ruthenium, oxygen, and/or nitrogen. For example, in a sputtering gas atmosphere containing an inert gas containing at least one selected from the group consisting of helium, neon, argon, helium, and neon, or containing the inert gas and containing a gas selected from the group consisting of oxygen and carbon dioxide. And a mixed gas of a reactive gas of at least one of a group consisting of nitric oxide gas and nitrogen dioxide gas is carried out in a sputtering gas atmosphere.

The composition and thickness of the phase shift film 30 are adjusted such that the phase shift film 30 has the above-described phase difference and transmittance. The composition of the phase shift film 30 can be controlled by the content ratio of the element constituting the sputtered palladium (for example, the ratio of the content of the transition metal to the content of ruthenium), the composition of the sputtering gas, the flow rate, and the like. The thickness of the phase shift film 30 can be controlled by sputtering power, sputtering time, and the like. Further, in the case where the sputtering apparatus is an in-line type sputtering apparatus, the thickness of the phase shifting film 30 can be controlled by the substrate transport speed. In this manner, the oxygen content of the phase shift film 30 is controlled to be 5 atom% or more and 70 atom% or less.

In the case where the phase shift film 30 includes a uniform single layer film, the film forming process is performed only once without changing the composition and flow rate of the sputtering gas. In the case where the phase shift film 30 includes a plurality of layers of different composition films, the composition and flow rate of the sputtering gas are changed for each film forming process to perform the above-described film forming process. The film phase shift film 30 may be formed by using a target having a different content ratio of elements which are sputtered with palladium. In the case where the phase shift film 30 includes a single layer film which is continuously changed in the thickness direction, the film forming process is performed only once as the composition and flow rate of the sputtering gas are changed as the film forming process progresses. In the case of performing a plurality of film forming processes, the sputtering power applied to the sputtered palladium can be made small.

2. Surface Treatment Step After forming the phase shift film 30 containing a transition metal halide material containing a transition metal, ruthenium, and oxygen, the surface of the phase shift film 30 is easily oxidized, and an oxide of a transition metal is easily formed. In order to suppress the penetration of the etching liquid due to the presence of the oxide of the transition metal, a surface treatment step of adjusting the state of the surface oxidation of the phase shifting film 30 is performed.
The surface treatment step of adjusting the surface oxidation state of the phase shifting film 30 includes a surface treatment by an acidic aqueous solution, a surface treatment by an alkaline aqueous solution, and a surface treatment by dry treatment such as ashing. Method and so on.
After the etching mask forming step described below, a composition gradient region is formed at the interface between the phase shift film 30 and the etching mask film 40, and the ratio of oxygen contained in the composition gradient region is stepwise and/or continuous toward the depth direction. Further, in the region where the ground is increased, and in the region from the interface between the phase shift film 30 and the etching mask film 40 to a depth of 10 nm, the ratio of oxygen to cerium is 3.0 or less, any surface treatment step can be performed.
For example, in the method of surface treatment by an acidic aqueous solution or the surface treatment by an aqueous alkaline solution, the surface of the phase shift film 30 can be adjusted by appropriately adjusting the concentration, temperature, and time of the acidic or basic aqueous solution. The state of oxidation. As a method of surface treatment by an acidic aqueous solution, and a surface treatment by an aqueous alkaline solution, a substrate on which a phase shift film of the phase shift film 30 is formed on the transparent substrate 20 is immersed in the above aqueous solution. And a method of bringing the aqueous solution into contact with the phase shift film 30, and the like.
3. Etching Mask Film Forming Step After the surface treatment for adjusting the surface oxidation state of the surface of the phase shift film 30, the etching mask film 40 is formed on the phase shift film 30 by sputtering.
As such, the phase shift mask substrate 10 is obtained.

The film formation of the etching mask film 40 uses sputtered palladium containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxycarbonate, etc.), for example, containing a component selected from the group consisting of helium, a sputtering gas atmosphere of an inert gas of at least one of a group consisting of helium, argon, helium, and neon, or comprising a group selected from the group consisting of helium, neon, argon, neon, and xenon At least one of the inert gas and the mixed gas containing at least one active gas selected from the group consisting of oxygen, nitrogen, nitrogen monoxide, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas, and fluorine gas Conducted in a sputtering atmosphere. Examples of the hydrocarbon-based gas include methane gas, butane gas, propane gas, and styrene gas.

In the case where the etching mask film 40 includes a uniform single-layer film, the film formation process is performed only once without changing the composition and flow rate of the sputtering gas. In the case where the etching mask film 40 includes a plurality of layers of different compositions, the film forming process is performed plural times by changing the composition and flow rate of the sputtering gas in each film forming process. In the case where the etching mask film 40 includes a single layer film which is continuously changed in the thickness direction, the film formation process is performed only once as the composition and flow rate of the sputtering gas are changed as the film forming process progresses.

Thus, by performing the surface treatment of the phase shift film 30 and the etching mask 40, and the surface treatment for adjusting the surface oxidation state of the surface of the phase shift film 30, the phase shift film 30 and the etching mask can be used. The interface of the film 40 forms a composition gradient region containing a region in which the ratio of oxygen increases stepwise and/or continuously toward the depth direction, and the interface between the phase offset film and the above etch mask film reaches a depth of 10 In the region of nm, the phase shift film 30 and the etching mask film 40 are formed to have a ratio of oxygen to cerium of 3.0 or less.

Further, the surface treatment for adjusting the surface oxidation state of the surface of the phase shifting film 30 has been described. However, in the film forming process of the phase shifting film 30, it is also possible to change the second half of the film forming process to make it difficult to make the phase shift. a type of gas on which the surface of the transfer film 30 is oxidized, or a gas species or the like added thereto, thereby including a region in which the ratio of oxygen in the composition gradient region increases stepwise and/or continuously toward the depth direction, and is shifted throughout the phase The ratio of the interface of the film to the above-mentioned etching mask film to a depth of 10 nm is such that the ratio of oxygen to cerium is 3.0 or less.

Further, since the phase shift mask substrate 10 shown in FIG. 1 is provided with the etching mask film 40 on the phase shift film 30, the etching mask film forming step is performed when the phase shift mask substrate 10 is manufactured. Further, when the etching mask film 40 is provided on the phase shift film 30 and the phase shift mask substrate having the resist film is provided on the etching mask film 40, the etching is performed after the etching mask forming step. A resist film is formed on the mask film 40.

The phase shift mask substrate 10 of the first embodiment forms a composition gradient region at the interface between the phase shift film 30 and the etching mask film 40, and the ratio of oxygen contained in the composition gradient region is stepwise toward the depth direction and/or Or a region which is continuously increased, and a phase shift film 30 and an etching mask are formed in a region where the ratio of oxygen to germanium is 3.0 or less over the interface between the phase shift film and the etching mask film to a depth of 10 nm. Film 40. Thereby, the etching liquid can be effectively inhibited from penetrating into the interface between the phase shifting film 30 and the etching mask film 40, which can contribute to the verticalization of the pattern cross section, and a phase shift film pattern having excellent CD uniformity can be obtained. The phase shift mask. Moreover, in the case of the phase shift mask, when the etching mask pattern remains on the phase shift film pattern, reflection with the photomask film or the display device substrate attached to the phase shift mask can be suppressed. influences. Further, in the phase shift mask substrate 10 of the first embodiment, a phase shift film pattern having a good cross-sectional shape, a small CD variation, and a high transmittance can be formed by wet etching. Therefore, it is possible to obtain a phase shift mask substrate capable of producing a phase shift mask which can accurately transfer a high-definition phase shift film pattern.

Embodiment 2.
In the second embodiment, a method of manufacturing a phase shift mask will be described.

Fig. 2 is a schematic view showing a method of manufacturing a phase shift mask.
The method of manufacturing the phase shift mask shown in FIG. 2 is a method of manufacturing a phase shift mask using the phase shift mask substrate 10 shown in FIG. 1, comprising the steps of: shifting the mask substrate 10 to the following phase a resist film is formed thereon; a resist film pattern 50 is formed by drawing a desired pattern on the resist film and developing (a first resist film pattern forming step); and the resist film pattern 50 is formed As the mask, the etching mask film 40 is patterned by wet etching to form an etching mask film pattern 40a (first etching mask film pattern forming step); by using the etching mask film pattern 40a as a mask The phase shift film 30 is subjected to wet etching to form a phase shift film pattern 30a on the transparent substrate 20 (phase shift film pattern forming step). Furthermore, the second resist film pattern forming step and the second etching mask film pattern forming step are further included.
Hereinafter, each step will be described in detail.

1. First Resist Film Pattern Forming Step In the first resist film pattern forming step, first, a resist film is formed on the etching mask film 40 of the phase shift mask substrate 10 of the first embodiment. The resist film material to be used is not particularly limited. For example, it is sufficient for a laser light having a wavelength selected from the wavelength range of 350 nm to 436 nm described below. Further, the resist film may be either a positive type or a negative type.
Thereafter, laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm is used to trace a desired pattern on the resist film. The pattern drawn on the resist film is a pattern to be formed on the phase shift film 30. Examples of the pattern drawn on the resist film include a line and a gap pattern or a hole pattern.
Thereafter, the resist film is developed by a specific developer, and as shown in FIG. 2(a), the first resist film pattern 50 is formed on the etching mask film 40.

2. First etching mask film pattern forming step In the first etching mask film pattern forming step, first, the etching mask film 40 is etched using the first resist film pattern 50 as a mask to form a first etching. The mask film pattern 40a. The etching mask film 40 is formed of a chromium-based material containing chromium (Cr). The etching liquid for etching the etching mask film 40 is not particularly limited as long as it can selectively etch the etching mask film 40. Specifically, an etching solution containing cerium ammonium nitrate and perchloric acid is mentioned.
Thereafter, using the resist stripping solution or by ashing, the first resist film pattern 50 is peeled off as shown in FIG. 2(b). The next phase shift film pattern forming step may be performed without peeling off the first resist film pattern 50 as needed.

3. Phase shift film pattern forming step In the first phase shift film pattern forming step, the phase shift film 30 is etched using the first etch mask film pattern 40a as a mask, as shown in FIG. 2(c). The phase shift film pattern 30a is formed. As the phase shift film pattern 30a, a line and gap pattern or a hole pattern can be cited. The etching liquid for etching the phase shift film 30 is not particularly limited as long as it can selectively etch the phase shift film 30. For example, an etching solution containing ammonium fluoride, phosphoric acid, and hydrogen peroxide, and an etching solution containing ammonium hydrogen fluoride and hydrogen chloride can be mentioned.

4. Second Resist Film Pattern Forming Step In the second resist film pattern forming step, first, a resist film covering the first etching mask film pattern 40a is formed. The resist film material to be used is not particularly limited. For example, it is sufficient for a laser light having a wavelength selected from the wavelength range of 350 nm to 436 nm described below. Further, the resist film may be either a positive type or a negative type.
Thereafter, laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm is used to trace a desired pattern on the resist film. The pattern drawn on the resist film is a light-shielding tape pattern that shields the peripheral region from the region where the phase shift film 30 is patterned, and a light-shielding tape pattern that shields the central portion of the phase-shifted film pattern. Further, the pattern drawn on the resist film may have a pattern in which the light-shielding band pattern for shielding the central portion of the phase-shifted film pattern 30a is not changed depending on the transmittance of the phase-shift film 30 with respect to the light to be exposed.
Thereafter, the resist film is developed by a specific developer, and as shown in FIG. 2(d), the second resist film pattern 60 is formed on the first etching mask pattern 40a.

5. Second etching mask pattern forming step In the second etching mask pattern forming step, the first etching mask pattern 40a is etched using the second resist film pattern 60 as a mask, as shown in FIG. As shown in (e), the second etching mask pattern 40b is formed. The first etch mask film pattern 40a is formed of a chromium-based material containing chromium (Cr). The etching liquid for etching the first etching mask pattern 40a is not particularly limited as long as it can selectively etch the first etching mask pattern 40a. For example, an etching solution containing cerium ammonium nitrate and perchloric acid can be mentioned.
Thereafter, the second resist film pattern 60 is peeled off by using a resist stripper or by ashing.
As such, the phase shift mask 100 is obtained.
Further, in the above description, the etching mask 40 has a function of blocking the transmission of the exposed light, but the etching mask 40 has only the hard surface when the phase shift film 30 is etched. In the case of the function of the mask, in the above description, the second resist film pattern forming step and the second etching mask pattern forming step are not performed, and after the phase shift film pattern forming step, the first etching mask is formed. The cover film pattern is peeled off to fabricate the phase shift mask 100.

According to the method of manufacturing a phase shift mask of the second embodiment, since the phase shift mask substrate of the first embodiment is used, a phase shift film pattern having a good cross-sectional shape and a small CD variation can be formed. Therefore, it is possible to manufacture a phase shift mask which can accurately transfer a high-definition phase shift film pattern. The phase shift mask manufactured in this manner can cope with the miniaturization of line and gap patterns or contact holes.

Embodiment 3.
In the third embodiment, a method of manufacturing a display device will be described. The display device is a step of performing the use of the phase shift mask 100 manufactured using the phase shift mask substrate 10 or the phase shift mask 100 manufactured by the method of manufacturing the phase shift mask 100 described above. (Photomask mounting step) and a step of transferring and transferring the transfer pattern to the resist film on the display device (pattern transfer step).
Hereinafter, each step will be described in detail.

1. Mounting Step In the placing step, the phase shift mask manufactured in the second embodiment is placed on the mask holder of the exposure apparatus. Here, the phase shift mask is disposed such that the projection optical system of the exposure apparatus is opposed to the resist film formed on the display device substrate.

2. Pattern Transfer Step In the pattern transfer step, the phase shift mask 100 is irradiated with the exposed light, and the phase shift film pattern is transferred to the resist film formed on the display device substrate. The light to be exposed is a composite light including light of a plurality of wavelengths selected from a wavelength region of 365 nm to 436 nm, or a single color selected by a filter or the like to cut off a certain wavelength region from a wavelength region of 365 nm to 436 nm. Light. For example, the light to be exposed is a composite light including i-rays, h-rays, and g-rays, or monochromatic light of i-rays. When the composite light is used as the light for exposure, the light intensity of the exposure can be increased and the productivity can be improved, so that the manufacturing cost of the display device can be reduced.

According to the method of manufacturing the display device of the third embodiment, it is possible to manufacture a high-definition display device which can suppress CD errors and has high resolution, fine lines and gap patterns or contact holes.
[Examples]

Example 1.
A. Phase-shifting reticle substrate and method of manufacturing the same In order to manufacture the phase-shifting reticle substrate of Example 1, first, as a transparent substrate 20, a 1214-size (1220 mm × 1400 mm) synthetic quartz glass substrate was prepared.

Thereafter, the main surface of the synthetic quartz glass substrate is mounted on a tray (not shown) toward the lower side, and is carried into the chamber of the in-line sputtering apparatus.
In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas, carbon dioxide gas (CO ₂ ), and nitrogen (N) are introduced while the first chamber is set to a specific degree of vacuum. ₂ ) a mixed gas of gas (Ar: 20 sccm, CO ₂ : 10 sccm, N ₂ : 20 sccm), applying a splash of 6.0 kW to the first sputtered palladium (molybdenum: 矽 = 1:4) containing molybdenum and niobium The plating power is used to deposit carbonitrides of molybdenum molybdenum containing molybdenum, niobium, oxygen, nitrogen and carbon on the main surface of the transparent substrate 20 by reactive sputtering. Then, a phase shift film 30 having a film thickness of 202 nm was formed. Further, after the phase shift film 30 is formed on the transparent substrate 20, it is taken out from the chamber, and the surface of the phase shift film 30 is subjected to surface treatment of the phase shift film 30 with an alkali-based aqueous solution. Further, the surface treatment conditions were set to an alkali concentration of 0.7%, a temperature of 30 degrees, and a surface treatment time of 1200 seconds.

Next, the transparent substrate 20 of the phase-shifted film 30 after the surface treatment is carried into the second chamber, and argon (Ar) gas and nitrogen (N ₂ ) are introduced while the second chamber is set to a specific degree of vacuum. Mixed gas of gas (Ar: 65 sccm, N ₂ : 15 sccm). Then, a sputtering power of 1.5 kW is applied to the second sputtered palladium containing chromium, and chromium and nitrogen-containing chromium nitride (CrN) is formed on the phase shift film 30 by reactive sputtering (film thickness 15 nm). ). Next, a mixed gas of argon (Ar) gas and methane (CH ₄ : 4.9%) gas (30 sccm) is introduced in a state where the third chamber is set to a specific degree of vacuum, and the third sputtered palladium containing chromium is introduced. A sputtering power of 8.5 kW was applied, and chromium chromium and carbon-containing chromium carbide (CrC) (film thickness: 60 nm) was formed by reactive sputtering on CrN. Finally, a mixed gas of argon (Ar) gas and methane (CH ₄ : 5.5%) gas, nitrogen (N ₂ ) gas, and oxygen (O ₂ ) are introduced in a state where the fourth chamber is set to a specific degree of vacuum. a mixed gas of gas (Ar+CH ₄ : 30 sccm, N ₂ : 8 sccm, O ₂ : 3 sccm), applying a sputtering power of 2.0 kW to the fourth sputtered palladium containing chromium by reactive sputtering on CrC A chromium carbonitride (CrCON) (thickness 30 nm) containing chromium, carbon, oxygen and nitrogen is formed. As described above, the etching mask film 40 having a laminated structure of a CrN layer, a CrC layer, and a CrCON layer is formed on the phase shift film 30.
Thus, the phase shift mask substrate 10 in which the phase shift film 30 and the etching mask film 40 are formed on the transparent substrate 20 is obtained.

The phase shifting film 30 of the obtained phase shifting mask substrate 10 (the phase shifting film 30 which surface-treated the surface of the phase shifting film 30 with an alkali aqueous solution) was used by MPM-100 manufactured by Lasertec. , the transmittance and phase difference were measured. The transmittance and phase difference of the phase shift film 30 are measured by using a phase shift film-attached substrate on which the phase shift film 30 is formed on the main surface of the synthetic quartz glass substrate produced on the same tray (dummy substrate) ). The transmittance and phase difference of the phase shift film 30 are measured by taking out the substrate (dummy substrate) of the phase shifting film from the chamber before forming the etching mask film 40. As a result, the transmittance was 22.1% (wavelength: 365 nm), and the phase difference was 161 degrees (wavelength: 365 nm). Further, the film thickness of the phase shift film 30 subjected to the surface treatment by the alkali aqueous solution was reduced to 183 nm as compared with the film thickness immediately after the film formation.
Further, the phase shift film 30 was measured for flatness change using UltraFLAT 200M (manufactured by Corning TROPEL Co., Ltd.), and the film stress was calculated and found to be 0.46 GPa. The phase shift film 30 has a small amount of change in transmittance and a change in phase difference between the chemical solution (sulfuric acid hydrogen peroxide mixture, aqueous ammonia hydrogen peroxide mixture, and ozone water) used for the phase shift mask cleaning. It has high resistance and washing resistance.

Further, with respect to the obtained phase shift mask substrate, the film surface reflectance and the optical density were measured by a spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation. The phase shift mask substrate (etch mask film 40) has a film surface reflectance of 8.3% (wavelength: 436 nm) and an optical density OD of 4.0 (wavelength: 436 nm). It is understood that the etching mask film functions as a light shielding film having a low reflectance on the surface of the film.

Further, for the obtained phase shift mask substrate 10, composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS). Fig. 3 is a graph showing the results of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate of Example 1. 3 shows the results of composition analysis of the etch mask film 40 and the phase shift film 30 on the phase shift film 30 side in the phase shift mask substrate. The horizontal axis of Fig. 3 indicates the depth (nm) in terms of SiO ₂ of the phase shift mask substrate 10 based on the outermost surface of the etching mask film 40, and the vertical axis indicates the content ratio (atomic %). In FIG. 3, each curve represents a change in the content ratio of cerium (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 3, in the result of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate 10, the interface between the phase shift film 30 and the etching mask film 40 (the ratio of the transition metal is self-biased) The film transfer film 30 is reduced toward the etching mask film 40, and the content of the transition metal becomes 0 atom% for the first time), and the ratio of chromium decreases from the etching mask film 40 toward the phase shift film 30, and the chromium content ratio becomes the first time. The region up to the position of 0 atom%, that is, the composition gradient region, the ratio of oxygen generated by the phase shift film 30 monotonically increases stepwise and/or continuously toward the depth direction.
Further, Fig. 7 is a graph showing the ratio of O/Si in the depth direction (the ratio of oxygen to yttrium) in the depth direction obtained by XPS for the phase shift mask substrates of Example 1 and Comparative Example 1. As shown in FIG. 7, in the phase shift mask substrate of Embodiment 1, the maximum ratio of oxygen to germanium in the region of the interface between the phase shift film 30 and the etching mask 40 to a depth of 10 nm is 2.0, is below 3.0. The interface is set to a position where the ratio of the transition metal (in this case, molybdenum) is self-phased when the composition of the phase shift mask substrate 10 is analyzed by X-ray photoelectron spectroscopy on the side of the self-etching mask film 40. The offset film 30 is reduced toward the etching mask film 40, and the content of the transition metal becomes 0 atom% at the first time.

The chromium (Cr) generated by the etching of the mask film 40 disappears to the phase shift film 30 which occurs due to the peak of oxygen (O) generated by the transparent substrate 20 (before the molybdenum (Mo) is rapidly reduced due to the phase shift film 30). In the uniform composition region, the content of molybdenum (Mo) is 12 atom% on average, the content of bismuth (Si) is 23 atom% on average, and the content of nitrogen (N) is 13 atom% on average, and the content of oxygen (O) is contained. The rate is 40 atom% on average, and the content of carbon (C) is 12 atom% on average, and the variation in the content ratio of each is 3 atom% or less.

B. Phase-shifting reticle and method of manufacturing the same In order to fabricate the phase-shifting reticle 100 using the phase-shifting reticle substrate 10 manufactured in the above manner, first, a resist coating device is used to phase-shift the reticle substrate A photoresist film is coated on the etch mask film 40 of 10.
Thereafter, a photoresist film having a film thickness of 520 nm was formed by a heating and cooling step.
Thereafter, the photoresist film is drawn using a laser drawing device, and after development and rinsing steps, a line and gap pattern having a line pattern width of 1.8 μm and a gap pattern width of 1.8 μm is formed on the etching mask film. Resist film pattern.

Thereafter, the etching mask pattern is used as a mask, and the etching mask film is wet-etched by a chromium etching solution containing cerium ammonium nitrate and perchloric acid to form a first etching mask pattern 40a.

Thereafter, the phase shift film 30 is wet-etched by using the first etching mask pattern 40a as a mask and diluting the molybdenum molybdenum etching solution obtained by mixing a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water. A phase shift film pattern 30a is formed.
Thereafter, the resist film pattern is peeled off.

Thereafter, the photoresist film is applied so as to cover the first etching mask pattern 40a by using a resist coating device.
Thereafter, a photoresist film having a film thickness of 520 nm was formed by a heating and cooling step.
Thereafter, the photoresist film is drawn using a laser drawing device, and a second resist film pattern 60 for forming a light shielding tape is formed on the first etching mask film pattern 40a by a development and rinsing step.

Thereafter, the first etching mask pattern 40a formed in the transfer pattern forming region is wetted by the second resist film pattern 60 as a mask by a chromium etching solution containing cerium ammonium nitrate and perchloric acid. Etching.
Thereafter, the second resist film pattern 60 is peeled off.

In this manner, the phase shift film pattern 30a formed in the transfer pattern forming region and the phase shift of the light shielding tape including the laminated structure of the phase shift film pattern 30a and the etching mask film pattern 40b are formed on the transparent substrate 20. Photomask 100.

The cross section of the resulting phase shift mask was observed by a scanning electron microscope. In the following Example 1 and Comparative Example 1, a scanning electron microscope was used in observing the cross section of the phase shift mask. 4 is a cross-sectional photograph of the phase shift mask of Embodiment 1.

As shown in FIG. 4, the phase shift film pattern formed in the phase shift mask of the first embodiment has a cross-sectional shape close to vertical which can sufficiently exhibit the phase shift effect. Further, in the phase shift film pattern, no penetration was observed in any of the interface with the etching mask pattern and the interface with the substrate. Further, it has a phase shift film pattern having a small hem width and a small CD deviation. In detail, the cross section of the phase shift film pattern includes a top surface, a lower surface, and a side surface of the phase shift film pattern. In the cross section of the phase offset film pattern, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 53 degrees. Therefore, an excellent phase shift effect is obtained for light that is exposed to light including a wavelength range of 300 nm or more and 500 nm or less, more specifically, a combined light of i-ray, h-ray, and g-ray. Phase shift mask.
Further, in the cross section of the phase shift film pattern of the first embodiment, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 53 degrees, which is more than Over-etching is performed at 45 degrees of the lower limit of the section control. Therefore, when the phase shift film pattern of Example 1 is formed, the cross-sectional shape can be further perpendicularized by performing over-etching.

The CD deviation of the phase shift film pattern of the phase shift mask was measured by SIR 8000 manufactured by Seiko Instruments NanoTechnology. The CD deviation was measured at 11 × 11 points in a region of 1100 mm × 1300 mm excluding the peripheral region of the substrate. The CD deviation is offset width from the target line and gap pattern (width of the line pattern: 1.8 μm, width of the gap pattern: 1.8 μm). In Example 1 and Comparative Example 1, the same apparatus was used for the measurement of CD deviation.
The CD deviation was 0.096 μm and was good.
Therefore, when the phase shift mask of the first embodiment is placed on the mask stage of the exposure apparatus and exposed to the resist film on the display apparatus, the transfer can be performed with a high precision of less than 2.0 μm. Fine pattern.

Example 2.
A. Phase-shifting mask substrate and method of manufacturing the same In order to manufacture the phase-shifting mask substrate of the second embodiment, as in the first embodiment, a synthetic quartz of 1214 size (1220 mm × 1400 mm) was prepared as the transparent substrate 20. glass substrate.

In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas and helium (He) are introduced in a state where the first chamber of the in-line type sputtering apparatus is set to a specific degree of vacuum. a mixed gas of gas and nitrogen (N ₂ ) gas (Ar: 18 sccm, He: 50 sccm, N ₂ : 13 sccm), for the first sputtered palladium containing molybdenum and niobium (molybdenum: 矽 = 1:9) A 7.6 kW sputtering power was applied, and an oxynitride containing molybdenum, niobium, oxygen, and nitrogen molybdenum molybdenum was deposited on the main surface of the transparent substrate 20 by reactive sputtering. Then, a phase shift film 30 having a film thickness of 150 nm was formed.

Next, after the phase shift film 30 is formed on the transparent substrate 20, the surface treatment is not performed, and an etching mask having a laminated structure of a CrN layer, a CrC layer, and a CrCON layer is formed on the phase shift film 30 as in the first embodiment. Film 40.
Thus, the phase shift mask substrate 10 in which the phase shift film 30 and the etching mask film 40 are formed on the transparent substrate 20 is obtained.

The phase shift film of the obtained phase shift mask substrate was measured for transmittance and phase difference by MPM-100 manufactured by Lasertec. The transmittance and phase difference of the phase shift film are measured by using a phase shift film-attached substrate (dummy substrate) on which the phase shift film 30 is formed on the main surface of the synthetic quartz glass substrate. . The transmittance and phase difference of the phase shift film are measured by taking out the substrate (dummy substrate) of the phase shifting film from the chamber before forming the etching mask film. As a result, the transmittance was 27.0% (wavelength: 405 nm), and the phase difference was 178 degrees (wavelength: 405 nm).
Further, the phase shift film was measured for flatness change using UltraFLAT 200M (manufactured by Corning TROPEL Co., Ltd.), and the film stress was calculated and found to be 0.21 GPa. The phase shift film 30 has a small amount of change in transmittance and a change in phase difference between the chemical solution (sulfuric acid hydrogen peroxide mixture, aqueous ammonia hydrogen peroxide mixture, and ozone water) used for the phase shift mask cleaning. It has high resistance and washing resistance.

Further, with respect to the obtained phase shift mask substrate, the film surface reflectance and the optical density were measured by a spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation. The phase shift mask substrate (etch mask film 40) has a film surface reflectance of 8.3% (wavelength: 436 nm) and an optical density OD of 4.0 (wavelength: 436 nm). It is understood that the etching mask film functions as a light shielding film having a low reflectance on the surface of the film.

Further, for the obtained phase shift mask substrate 10, composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS). Fig. 8 is a view showing the result of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate of Example 2. Fig. 8 shows the result of composition analysis of the etching mask film 40 and the phase shift film 30 on the phase shift film 30 side in the phase shift mask substrate. The horizontal axis of Fig. 8 indicates the depth (nm) in terms of SiO ₂ of the phase shift mask substrate 10 based on the outermost surface of the etching mask film 40, and the vertical axis indicates the content ratio (atomic %). In FIG. 8, each curve shows a change in the content ratio of cerium (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 8, in the result of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate 10, the interface between the phase shift film 30 and the etch mask film 40 (the ratio of the transition metal is self-biased) The film transfer film 30 is reduced toward the etching mask film 40, and the content of the transition metal becomes 0 atom% for the first time), and the ratio of chromium decreases from the etching mask film 40 toward the phase shift film 30, and the chromium content ratio becomes the first time. In the region of the composition gradient region, the region from the position of 0 atom%, from the interface between the phase shift film 30 and the etching mask film 40, the ratio of oxygen increases toward the depth direction and decreases.
Further, Fig. 10 is a graph showing the O/Si ratio (the ratio of oxygen to yttrium content) in the depth direction obtained by XPS for the phase shift mask substrates of Example 2 and Example 3. As shown in FIG. 10, the maximum ratio of oxygen to yttrium is 2.0 in the region from the interface between the phase shift film 30 and the etch mask 40 to a depth of 10 nm, which is 3.0 or less.

The chromium (Cr) generated by the etching of the mask film 40 disappears to the phase shift film 30 which occurs due to the peak of oxygen (O) generated by the transparent substrate 20 (before the molybdenum (Mo) is rapidly reduced due to the phase shift film 30). In the uniform composition region, the content of molybdenum (Mo) is 8 atom% on average, the content of bismuth (Si) is 40 atom% on average, and the content of nitrogen (N) is 46 atom% on average, and the content of oxygen (O) The rate is an average of 6 atom%. In the phase shift film 30, the variation in the content ratio of molybdenum (Mo) is the smallest, and is 2 atom% or less. Next, the variation in the content ratio of cerium (Si) is 3 atom% or less, and the content ratio of nitrogen (N) is The variation is 4 atom% or less, and the variation in the content ratio of oxygen (O) is 5 atom% or less.

B. Phase-shifting reticle and method of manufacturing the same A phase-shifting reticle was produced by the same method as in Example 1 using the phase-shifted reticle substrate manufactured in the above manner.
The cross section of the resulting phase shift mask was observed by a scanning electron microscope. Figure 9 is a cross-sectional photograph of the phase shift mask of Example 2.

As shown in Fig. 9, the phase shift film pattern formed in the phase shift mask of the second embodiment has a cross-sectional shape close to vertical which can sufficiently exhibit the phase shift effect. Further, in the phase shift film pattern, no penetration was observed in any of the interface with the etching mask pattern and the interface with the substrate. Further, it has a phase shift film pattern having a small hem width and a small CD deviation. In detail, the cross section of the phase shift film pattern includes a top surface, a lower surface, and a side surface of the phase shift film pattern. In the cross section of the phase shift film pattern, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 74 degrees. Therefore, an excellent phase shift effect is obtained for light that is exposed to light including a wavelength range of 300 nm or more and 500 nm or less, more specifically, a combined light of i-ray, h-ray, and g-ray. Phase shift mask.
Further, the CD deviation was 0.092 μm and was good.
Further, in the cross section of the phase shift film pattern of the second embodiment, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 74 degrees, which is more than Over-etching is performed at 45 degrees of the lower limit of the section control. Therefore, when the phase shift film pattern of Example 2 is formed, the cross-sectional shape can be further perpendicularized by performing over-etching.
Therefore, when the phase shift mask of the second embodiment is placed on the mask stage of the exposure apparatus and exposed to the resist film on the display apparatus, the transfer can be performed with a high precision of less than 2.0 μm. Fine pattern.

Example 3.
A. Phase-shifting mask substrate and method of manufacturing the same In order to manufacture the phase-shifting mask substrate of Example 3, as in the case of Example 1, a synthetic quartz of 1214 size (1220 mm × 1400 mm) was prepared as the transparent substrate 20. glass substrate.
In order to form the phase shift film 30 on the main surface of the transparent substrate 20, first, argon (Ar) gas and helium (He) are introduced in a state where the first chamber of the in-line type sputtering apparatus is set to a specific degree of vacuum. a mixture of gas, nitrogen (N ₂ ) gas, and nitric oxide gas (NO) (Ar: 18 sccm, He: 50 sccm, N ₂ : 13 sccm, NO: 4 sccm), containing molybdenum and niobium The first sputtering palladium (molybdenum: 矽 = 1:9) is applied with a sputtering power of 7.6 kW, and molybdenum, antimony, oxygen, and nitrogen are deposited on the main surface of the transparent substrate 20 by reactive sputtering. Nitrogen oxides. Then, a phase shift film 30 having a film thickness of 140 nm was formed. Then, after the phase shift film 30 is formed on the transparent substrate 20, it is taken out from the chamber, and the surface of the phase shift film 30 is subjected to surface treatment of the phase shift film 30 with an alkali aqueous solution under the same conditions as in the first embodiment. .

Next, in the same manner as in the first embodiment, an etching mask film 40 having a laminated structure of a CrN layer, a CrC layer, and a CrCON layer is formed on the phase shift film 30.
Thus, the phase shift mask substrate 10 in which the phase shift film 30 and the etching mask film 40 are formed on the transparent substrate 20 is obtained.

The phase shift film of the obtained phase shift mask substrate was measured for transmittance and phase difference by MPM-100 manufactured by Lasertec. The transmittance and phase difference of the phase shift film are measured by using a phase shift film-attached substrate (dummy substrate) on which the phase shift film 30 is formed on the main surface of the synthetic quartz glass substrate. . The transmittance and phase difference of the phase shift film are measured by taking out the substrate (dummy substrate) of the phase shifting film from the chamber before forming the etching mask film. As a result, the transmittance was 33.0% (wavelength: 365 nm), and the phase difference was 169 degrees (wavelength 365 nm).
Further, with respect to the phase shift film, the flatness change was measured using an UltraFLAT 200M (manufactured by Corning TROPEL Co., Ltd.), and the film stress was calculated and found to be 0.26 GPa. The phase shift film 30 has a small amount of change in transmittance and a change in phase difference between the chemical solution (sulfuric acid hydrogen peroxide mixture, aqueous ammonia hydrogen peroxide mixture, and ozone water) used for the phase shift mask cleaning. It has high resistance and washing resistance.

Further, with respect to the obtained phase shift mask substrate, the film surface reflectance and the optical density were measured by a spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation. The phase shift mask substrate (etch mask film 40) has a film surface reflectance of 8.3% (wavelength: 436 nm) and an optical density OD of 4.0 (wavelength: 436 nm). It is understood that the etching mask film functions as a light shielding film having a low reflectance on the surface of the film.
Further, for the obtained phase shift mask substrate 10, composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS). Fig. 11 is a view showing the results of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate of Example 3. Fig. 11 shows the results of composition analysis of the etching mask film 40 and the phase shift film 30 on the phase shift film 30 side in the phase shift mask substrate. The horizontal axis of Fig. 11 indicates the depth (nm) in terms of SiO ₂ of the phase shift mask substrate 10 based on the outermost surface of the etching mask film 40, and the vertical axis indicates the content ratio (atomic %). In FIG. 8, each curve shows a change in the content ratio of cerium (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 11, in the result of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate 10, the interface between the phase shift film 30 and the etch mask film 40 (the ratio of the transition metal is self-biased) The film transfer film 30 is reduced toward the etching mask film 40, and the content of the transition metal becomes 0 atom% for the first time), and the ratio of chromium decreases from the etching mask film 40 toward the phase shift film 30, and the chromium content ratio becomes the first time. In the region of the composition gradient region, the region from the position of 0 atom%, from the interface between the phase shift film 30 and the etching mask film 40, the ratio of oxygen increases toward the depth direction and decreases.
Further, as shown in FIG. 10, the maximum ratio of oxygen to yttrium is 2.4 in the region from the interface between the phase shift film 30 and the etch mask 40 to a depth of 10 nm, which is 3.0 or less.

The chromium (Cr) generated by the etching of the mask film 40 disappears to the phase shift film 30 which occurs due to the peak of oxygen (O) generated by the transparent substrate 20 (before the molybdenum (Mo) is rapidly reduced due to the phase shift film 30). In the uniform composition region, the content of molybdenum (Mo) is 7 atom% on average, the content of bismuth (Si) is 38 atom% on average, and the content of nitrogen (N) is 46 atom% on average, and the content of oxygen (O) The rate is an average of 9 atom%. In the phase shift film 30, the fluctuation of the content of molybdenum (Mo) is the smallest, and is 1 atom% or less, and secondly, the variation of the content of cerium (Si) is 2 atom% or less, and the content of oxygen (O) is The variation is 3 atom% or less, and the variation in the content ratio of nitrogen (N) is 4 atom% or less.

B. Phase-shifting reticle and method of manufacturing the same A phase-shifting reticle was produced by the same method as in Example 1 using the phase-shifted reticle substrate manufactured in the above manner.
The cross section of the resulting phase shift mask was observed by a scanning electron microscope. Figure 12 is a cross-sectional photograph of the phase shift mask of Example 3.

As shown in FIG. 12, the phase shift film pattern formed in the phase shift mask of Example 3 has a cross-sectional shape close to vertical which can sufficiently exhibit the phase shift effect. Further, in the phase shift film pattern, no penetration was observed in any of the interface with the etching mask pattern and the interface with the substrate. Further, it has a phase shift film pattern having a small hem width and a small CD deviation. In detail, the cross section of the phase shift film pattern includes a top surface, a lower surface, and a side surface of the phase shift film pattern. In the cross section of the phase shift film pattern, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 79 degrees. Therefore, an excellent phase shift effect is obtained for light that is exposed to light including a wavelength range of 300 nm or more and 500 nm or less, more specifically, a combined light of i-ray, h-ray, and g-ray. Phase shift mask.
Further, the CD deviation was good at 0.094 μm.
Further, in the cross section of the phase shift film pattern of the third embodiment, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 79 degrees, which is more than Over-etching is performed at 45 degrees of the lower limit of the section control. Therefore, when the phase shift film pattern of Example 2 is formed, the cross-sectional shape can be further perpendicularized by performing over-etching.
Therefore, when the phase shift mask of the second embodiment is placed on the mask stage of the exposure apparatus and exposed to the resist film on the display apparatus, the transfer can be performed with a high precision of less than 2.0 μm. Fine pattern.

Comparative Example 1.
A. Phase-shifting mask base and manufacturing method thereof In order to manufacture the phase-shifting mask base of Comparative Example 1, a synthetic quartz glass of 1214 size (1220 mm × 1400 mm) was prepared as a transparent substrate in the same manner as in Example 1. Substrate.
The synthetic quartz glass substrate was carried into the chamber of the in-line type sputtering apparatus by the same method as in the first embodiment. As the first sputter palladium, the second sputter palladium, the third sputter palladium, and the fourth sputter palladium, the same sputtering palladium material as in the first embodiment was used.
Then, after the phase shift film is formed on the transparent substrate, it is taken out from the chamber, and the surface of the phase shift film is washed with pure water. The pure water washing conditions were set to a temperature of 30 degrees and a surface treatment time of 300 seconds.
Thereafter, an etching mask film was formed by the same method as in Example 1.
In this manner, a phase shift mask substrate having a phase offset film and an etch mask film formed on the transparent substrate is obtained.

The phase shift film of the phase shift mask substrate obtained (the phase shift film which was washed with pure water on the surface of the phase shift film) was measured for transmittance and phase difference by MPM-100 manufactured by Lasertec. . The transmittance and phase difference of the phase shift film are measured by using a phase shift film-attached substrate (dummy substrate) on which the phase shift film 30 is formed on the main surface of the synthetic quartz glass substrate. . The transmittance and phase difference of the phase shift film are measured by taking out the substrate (dummy substrate) of the phase shifting film from the chamber before forming the etching mask film. As a result, the transmittance was 20.0% (wavelength: 365 nm), and the phase difference was 176 degrees (wavelength: 365 nm). Further, the film thickness of the phase shift film treated by the pure water treatment was reduced to 198 nm as compared with the film thickness immediately after the film formation.
Further, with respect to the phase shift film, the flatness change was measured using an UltraFLAT 200M (manufactured by Corning TROPEL Co., Ltd.), and the film stress was calculated and found to be 0.46 GPa. The phase shift film 30 has a small amount of change in transmittance and a change in phase difference between the chemical solution (sulfuric acid hydrogen peroxide mixture, aqueous ammonia hydrogen peroxide mixture, and ozone water) used for the phase shift mask cleaning. It has high resistance and washing resistance.

Further, with respect to the obtained phase shift mask substrate, the film surface reflectance and the optical density were measured by a spectrophotometer SolidSpec-3700 manufactured by Shimadzu Corporation. The phase shift mask substrate (etch mask film) has a film surface reflectance of 8.3% (wavelength: 436 nm) and an optical density OD of 4.0 (wavelength: 436 nm). It is understood that the etching mask film functions as a light shielding film having a low reflectance on the surface of the film.

Further, for the obtained phase shift mask substrate, composition analysis in the depth direction was performed by X-ray photoelectron spectroscopy (XPS). Fig. 5 shows the results of composition analysis of the depth direction obtained by XPS for the phase shift mask substrate of Comparative Example 1. Fig. 5 shows the result of composition analysis of the etching mask film 40 and the phase shift film 30 on the phase shift film 30 side in the phase shift mask substrate. The horizontal axis of Fig. 5 indicates the depth (nm) in terms of SiO ₂ in terms of the phase shift mask base based on the outermost surface of the etching mask 40, and the vertical axis indicates the content ratio (atomic %). In FIG. 5, each curve represents a change in the content ratio of cerium (Si), nitrogen (N), oxygen (O), carbon (C), chromium (Cr), and molybdenum (Mo).

As shown in FIG. 5, in the composition analysis result of the depth direction obtained by XPS for the phase shift mask base, in the composition gradient region, the ratio of oxygen generated by the phase shift film increases sharply toward the depth direction. The transition is made at a substantially constant ratio equivalent to the ratio of oxygen in the uniform region of the above composition.
Further, as shown in Fig. 7, the maximum ratio of oxygen to yttrium content was 6.4 over the interface between the phase shift film and the etch mask film to a depth of 10 nm, and there was a region exceeding 3.0. Further, since the chromium (Cr) generated by the etching of the mask film 40 disappears into a uniform region of the phase shift film 30 which occurs due to the peak of oxygen (O) generated by the transparent substrate 20, molybdenum, niobium, nitrogen, oxygen, carbon The content ratio is substantially the same as that of the first embodiment.

B. Phase-shifting reticle and method of manufacturing the same A phase-shifting reticle was produced by the same method as in Example 1 using the phase-shifted reticle substrate manufactured in the above manner.
The cross section of the resulting phase shift mask was observed by a scanning electron microscope. Figure 6 is a cross-sectional photograph of the phase shift mask of Comparative Example 1.

As shown in FIG. 6, the phase shift film pattern formed in the phase shift mask of Comparative Example 1 was a straight taper shape. In the cross section of the phase offset film pattern, the angle at which the upper surface is in contact with the side surface (upper side) and the portion where the side surface is in contact with the lower surface (lower side) is 5 degrees. Therefore, the obtained phase shift mask cannot obtain light for exposure of light including a wavelength range of 300 nm or more and 500 nm or less, more specifically, combined light of i-ray, h-ray, and g-ray. Full phase shift effect.
Further, the CD deviation was 0.230 μm.
Further, in the cross section of the phase shift film pattern of Comparative Example 1, the portion where the upper surface meets the side surface (the upper side) and the portion where the side surface and the lower surface meet (the lower side) form an angle of 5 degrees, which is less than The lower limit of the cross-section control is 45 degrees by over-etching. Therefore, when the phase shift film pattern of Comparative Example 1 was formed, it was not expected to further cross-sectional shape by over-etching.
Therefore, when the phase shift mask of Comparative Example 1 is placed on the mask stage of the exposure apparatus and the resist film is transferred to the display apparatus, it is predicted that the transfer cannot be as small as 2.0 μm. pattern.

Further, as shown in FIG. 7, the ratio of oxygen to yttrium exceeded 3.0 in the region from the interface between the phase shift film 30 and the etch mask film 40 to a depth of 10 nm.
Considering these aspects, and the composition of the first embodiment and the comparative example 1 in the uniform region are substantially the same, it can be said that the interface between the phase-shifted film and the etched mask film reaches a depth of 10 nm, and oxygen is relative to 矽. The content ratio of 3.0 or less is an important factor for obtaining a phase shift mask substrate having a high transmittance of a cross-sectional shape in which the phase shift film can be sufficiently exhibited as a phase shift effect.

Further, in the above embodiment, the case where molybdenum is used as the transition metal has been described, and the effect equivalent to the above can be obtained also in the case of using other transition metals.
Moreover, in the above-described embodiments, the phase shift mask substrate for display device manufacturing and the phase shift mask for manufacturing the display device have been described, but the invention is not limited thereto. The phase shift mask substrate and the phase shift mask of the present invention can also be applied to semiconductor device manufacturing, MEMS (Micro Electro Mechanical System) manufacturing, and printed circuit board.
Further, in the above embodiment, the example in which the size of the transparent substrate is 8092 size (800 mm × 920 mm × 10 mm) has been described, but the present invention is not limited thereto. In the case of a phase shift mask substrate for manufacturing a display device, a large-sized transparent substrate having a length of one side of 300 mm or more is used. The size of the transparent substrate used for the phase shift mask substrate for manufacturing a display device is, for example, 330 mm × 450 mm or more and 2280 mm × 3130 mm or less.
Further, in the case of a semiconductor device manufacturing, a MEMS manufacturing, or a phase shifting mask substrate for a printed circuit board, a small-sized transparent substrate having a length of one side of 9 inches or less is used. The size of the transparent substrate used for the phase shift mask substrate for the above use is, for example, 63.1 mm × 63.1 mm or more and 228.6 mm × 228.6 mm or less. Generally, for semiconductor manufacturing and MEMS manufacturing, 6025 size (152 mm × 152 mm) or 5009 size (126.6 mm × 126.6 mm) is used, and the printed circuit board is 7012 size (177.4 mm × 177.4 mm) or 9012 size (228.6 mm). ×228.6 mm).

10‧‧‧ phase offset mask base

20‧‧‧Transparent substrate

30‧‧‧ phase offset film

30a‧‧‧phase offset film pattern

40‧‧‧Erase mask film

40a‧‧‧1st etched mask pattern

40b‧‧‧2nd etched mask pattern

50‧‧‧1st resist film pattern

60‧‧‧2nd resist film pattern

100‧‧‧ phase offset mask

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the constitution of a film of a phase shift mask base.

2(a) to 2(e) are schematic views showing the steps of manufacturing the phase shift mask.

Fig. 3 is a view showing the result of composition analysis in the depth direction of the phase shift mask substrate of Example 1.

4 is a cross-sectional photograph of the phase shift mask of Embodiment 1.

Fig. 5 is a graph showing the results of composition analysis in the depth direction of the phase shift mask substrate of Comparative Example 1.

Figure 6 is a cross-sectional photograph of the phase shift mask of Comparative Example 1.

Figure 7 is a graph showing the O/Si ratio in the depth direction obtained by XPS (X-ray Photoelectron Spectroscopy) for the phase shift mask substrate of Example 1 and Comparative Example 1 (oxygen vs.矽The ratio of the ratio).

Fig. 8 is a view showing the result of composition analysis in the depth direction of the phase shift mask substrate of Example 2.

Figure 9 is a cross-sectional photograph of the phase shift mask of Example 2.

Fig. 10 is a graph showing the O/Si ratio (the ratio of oxygen to yttrium) in the depth direction obtained by XPS for the phase shift mask substrates of Examples 2 and 3.

Fig. 11 is a view showing the result of composition analysis in the depth direction of the phase shift mask substrate of Example 3.

Figure 12 is a cross-sectional photograph of the phase shift mask of Example 3.

Claims (11)

A phase shift mask substrate characterized in that it has a phase shift film on a transparent substrate and an etch mask film on the phase shift film, and The phase shifting mask base master is used for wet etching the phase shifting film by using the etching mask film to form a desired pattern of the etching mask film as a mask a phase shift mask having a phase offset film pattern formed on the transparent substrate by etching, The phase shift film contains a transition metal, ruthenium, and oxygen, and the oxygen content is 5 atom% or more and 70 atom% or less. Forming a gradient region at an interface between the phase shifting film and the etching mask film, wherein the composition gradient region includes a region in which the ratio of the oxygen increases stepwise and/or continuously toward the depth direction. The content ratio of oxygen to cerium is 3.0 or less over the interface between the phase shifting film and the etch mask film to a depth of 10 nm. The phase shift mask substrate of claim 1 wherein said phase shifting film comprises a plurality of layers. The phase shift mask substrate of claim 1 wherein said phase shifting film comprises a single layer. The phase shift mask substrate of any one of claims 1 to 3, wherein the phase shifting film comprises nitrogen. The phase shift mask substrate of claim 4, wherein the phase shift film has a nitrogen content of 2 atom% or more and 60 atom% or less. The phase shift mask substrate according to any one of claims 1 to 3, wherein the phase shift film has a film stress of 0.2 GPa or more and 0.8 GPa or less. The phase shift mask substrate of any one of claims 1 to 3, wherein the etch mask film comprises a chrome-based material. The phase shift mask substrate of any one of claims 1 to 3, wherein the etch mask film contains at least one of nitrogen, oxygen, and carbon. The phase shift mask substrate according to any one of claims 1 to 3, wherein the transparent substrate is a rectangular substrate, and the short side of the transparent substrate has a length of 300 mm or more. A method of manufacturing a phase shift mask, comprising the steps of: Preparing a phase shift mask substrate according to any one of claims 1 to 9; Forming a resist film on the phase shift mask substrate; A resist film pattern is formed by drawing a desired pattern on the resist film, and the resist film pattern is used as a mask, and the etching mask film is patterned by wet etching to form Etching the mask film pattern; and The phase shift film is wet-etched by the etching of the mask film pattern to form a phase shift film pattern on the transparent substrate. A method of manufacturing a display device, comprising the steps of: using a phase shift mask fabricated using the phase shift mask substrate of any one of claims 1 to 9 or using the method of claim 10 A phase shift mask manufactured by a method of manufacturing a phase shift mask, which exposes a transfer pattern to a resist film on a display device.