JP2024004082A - Mask blank, mask for transcription, method for manufacturing mask for transcription, and method for manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mask blank having a semipermeable film capable of enhancing a transmittance adjustment effect by increasing the transmittance to exposure light, capable of suppressing an in-plane distribution of the transmittance to a plurality of wavelengths of exposure light, and capable of suppressing a transmittance fluctuation due to a film thickness fluctuation.

SOLUTION: A mask blank comprises a transparent substrate and a semi-transparent film provided on a main surface of the transparent substrate, in which both of a refractive index n and an extinction coefficient k of the semi-transparent film to light with a wavelength of 365 nm and a refractive index n and an extinction coefficient k to light with a wavelength of 405 nm satisfy the relationship of (Formula 1) and (Formula 2). (Formula 1) k≥0.282×n-0.514 (Formula 2) k≤0.500×n+0.800

SELECTED DRAWING: Figure 11

COPYRIGHT: (C)2024,JPO&INPIT

Description

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

In the field of FPD masks, attempts have been made to reduce the number of masks by using gray-tone masks (also called multi-tone masks) having semi-transparent films (so-called half-transparent films for gray-tone masks). (Non-patent Document 1).
Here, as shown in FIG. 12(1), the gray tone mask has a light shielding part 1, a transmitting part 2, and a gray tone part 3 on a transparent substrate (light-transmitting substrate). The gray tone part 3 has a function of adjusting the amount of transmission, and for example, as shown in FIG. By reducing the amount of light transmitted through these areas and reducing the amount of light irradiated by these areas, the reduced film thickness of the photoresist corresponding to the areas after development is reduced to a desired value. It is formed for the purpose of controlling the

When using a gray tone mask mounted on a large exposure device using a mirror projection method or a lens method using a lens, the total exposure amount of the exposure light that has passed through the gray tone section 3 will be insufficient. The positive photoresist exposed through 3 remains on the substrate with only a thinner film thickness. In other words, the solubility of the resist in the developing solution differs between the part corresponding to the normal light-shielding part 1 and the part corresponding to the gray-tone part 3 due to the difference in exposure amount, so the resist shape after development is as shown in FIG. ), the portion 1' corresponding to the normal light-shielding portion 1 is approximately 1 μm thick, the portion 3′ corresponding to the gray tone portion 3 is approximately 0.4 to 0.5 μm thick, and the portion corresponding to the transmitting portion 2 is approximately 1 μm thick. becomes the part 2' where there is no resist. Then, the first etching of the substrate to be processed is performed on the portion 2' where there is no resist, the resist in the thin portion 3' corresponding to the gray tone portion 3 is removed by ashing, etc., and the second etching is performed on this portion. , one mask performs the same process as two conventional masks, reducing the number of masks.
Moreover, recently, the above-mentioned gray tone mask is mounted on a large-scale exposure device using a close-up exposure (projection exposure) method, and is used for forming photo spacers for color filters.

The gray tone mask shown in FIG. 12(1) is manufactured using, for example, the mask blank described in Patent Document 1. The mask blank described in Patent Document 1 has at least a semi-transparent film having a function of adjusting the amount of transmission on a translucent substrate, and the semi-transparent film is radiated from an ultra-high pressure mercury lamp. The semi-transparent film is characterized in that the fluctuation width of the transmittance of the semi-transparent film is controlled to be within a range of less than 5% at least in a wavelength band extending from the i-line to the g-line. Specifically, this semi-transparent film is made of materials such as CrN (film thickness 20-250 angstroms (2-25 nm), MoSi ₄ (film thickness 15-200 angstroms (1.5-20 nm)) and film thickness. Illustrated.

Monthly FPD Intelligence, p.31-35, May 1999

Japanese Patent Application Publication No. 2007-199700

When forming a semi-transparent film (semi-transparent film) having a desired transmittance using the material exemplified in Patent Document 1, the film thickness of the semi-transparent film is controlled. However, when manufacturing a large-sized gray-tone mask, a transmittance distribution occurs due to the film thickness distribution within the plane of the substrate, making it difficult to manufacture a gray-tone mask with good in-plane transmittance uniformity. ing.
In addition, in the process of forming a semi-transparent film in a mask blank, the maximum film thickness of the semi-transparent film is as thin as about 80 nm, so it is difficult to form a film according to the designed film thickness, and it is difficult to form a film according to the designed film thickness. A slight difference in film thickness may occur. If you design a semi-transparent membrane without considering the range of variation in transmittance due to film thickness, as described above, when the thickness of the semi-transparent membrane deviates from the design value, the transmittance will change. Therefore, there was a problem that the in-plane distribution of transmittance became large.

In particular, when a gray-tone mask is mounted on a large exposure device using a close-up exposure method to transfer a pattern onto an object, foreign matter may appear on the surface of the gray-tone mask due to the narrow distance between the gray-tone mask and the object. Pellicles cannot be used to prevent fouling.
Therefore, after using a gray-tone mask multiple times, chemical cleaning using an alkali or acid is usually performed to remove foreign matter adhering to the surface of the gray-tone mask. However, a problem arises in that the chemical cleaning described above causes membrane thinning of the semi-permeable membrane and changes in the transmittance of the semi-permeable membrane.

Furthermore, in the field of FPD masks, composite light selected from a predetermined wavelength range is sometimes used as exposure light. For example, composite light including i-line (365 nm), h-line (405 nm), and g-line (436 nm) is often used as exposure light. In such cases, simply adjusting the transmittance to a desired value for any one representative wavelength will suppress the in-plane distribution of transmittance for multiple wavelengths in the exposure light, and reduce transmittance fluctuations due to changes in film thickness. A problem has arisen in that it is not possible to sufficiently suppress the

In addition, in recent years, as transfer mask patterns have become finer and more complex, in order to enable higher-resolution pattern transfer, we have increased the transmittance of exposure light (for example, by increasing the transmittance by 20%). The demand for semi-transparent membranes (as described above) is increasing. Furthermore, requirements for in-plane uniformity of the pattern of the photosensitive film formed after exposure transfer is performed on the photosensitive film on the transfer target are becoming stricter, and the transmittance for multiple wavelengths of exposure light is becoming more stringent. The demand for in-plane uniformity is increasing. However, by increasing the transmittance for exposure light, it becomes more difficult to suppress the in-plane distribution of transmittance for a plurality of wavelengths in the exposure light and to suppress transmittance fluctuations due to film thickness variations.

Accordingly, the present invention relates to a mask blank for manufacturing an FPD device that has at least a semi-transparent film having a function of adjusting the amount of exposure light transmitted on a transparent substrate. It is an object of the present invention to provide a mask blank having a semi-transparent film that can suppress the in-plane distribution of transmittance for a plurality of wavelengths in exposure light even if there is a change in the transmittance due to changes in film thickness. Furthermore, even when the transmittance of the exposure light is increased, the present invention can suppress the in-plane distribution of the transmittance for multiple wavelengths of the exposure light, and can suppress the transmittance fluctuation due to film thickness variation. The present invention aims to provide a transfer mask having a film and a method for manufacturing the transfer mask. An object of the present invention is to provide a method for manufacturing a display device using such a transfer mask.

The present invention has the following configuration as a means for solving the above problems.

(Structure 1) A mask blank comprising a transparent substrate and a semi-transparent film provided on the main surface of the transparent substrate,
a refractive index n and an extinction coefficient k for light with a wavelength of 365 nm in the semi-transparent film;
A mask blank characterized in that a refractive index n and an extinction coefficient k for light having a wavelength of 405 nm both satisfy the relationships of (Formula 1) and (Formula 2).
(Formula 1) k≧0.282×n−0.514
(Formula 2) k≦0.500×n+0.800

(Structure 2) The mask blank according to Structure 1, wherein the semi-transparent film has an extinction coefficient k greater than 0 for light with a wavelength of 365 nm.

(Structure 3) The mask blank according to Structure 1, wherein the semi-transparent film has a refractive index n of 2.0 or more for light having a wavelength of 365 nm.

(Structure 4) The mask blank according to Structure 1, wherein the thickness of the semi-transparent film is 30 nm or more and 70 nm or less.

(Structure 5) The mask blank according to Structure 1, wherein the semi-transparent film has a transmittance of 20% or more and 70% or less for light having a wavelength of 365 nm.

(Structure 6) The mask blank according to Structure 1, wherein the semi-transparent film has a phase difference of 0 degrees or more and 120 degrees or less with respect to light having a wavelength of 365 nm.

(Structure 7) The mask blank according to Structure 1, wherein the refractive index n and extinction coefficient k for light with a wavelength of 436 nm in the semi-transparent film also satisfy the relationships of (Formula 1) and (Formula 2).

(Structure 8) The mask blank according to Structure 1, wherein the semi-transparent film contains metal, silicon, and nitrogen.

(Structure 9) The mask blank according to Structure 1, further comprising an etching mask film having etching selectivity different from that of the semi-transparent film on the semi-transparent film.

(Structure 10) The mask blank according to Structure 9, wherein the etching mask film contains chromium.

(Structure 11) A transfer mask, characterized in that a transfer pattern is formed on the semi-transparent film of the mask blank according to Structure 1.

(Structure 12) A transfer mask, wherein a transfer pattern is formed on the semi-transparent film of the mask blank according to Structure 9, and a pattern different from the transfer pattern is formed on the etching mask film.

(Structure 13) A step of preparing the mask blank according to Structure 1;
forming a resist film having a transfer pattern on the semi-transparent film;
performing wet etching using the resist film as a mask to form a transfer pattern on the semi-transparent film;
A method for manufacturing a transfer mask, comprising:

(Structure 14) A step of preparing the mask blank according to Structure 9;
forming a resist film having a transfer pattern on the etching mask film;
performing wet etching using the resist film as a mask to form a transfer pattern on the etching mask film;
performing wet etching using an etching mask film on which the transfer pattern is formed as a mask to form a transfer pattern on the semi-transparent film;
A method for manufacturing a transfer mask, comprising:

(Structure 15) A step of placing the transfer mask according to Structure 11 or 12 on a mask stage of an exposure device;
irradiating the transfer mask with exposure light to transfer the transfer pattern to a photosensitive film provided on a substrate for a display device;
A method for manufacturing a display device, comprising:

(Structure 16) The method for manufacturing a display device according to Structure 15, wherein the exposure light is composite light including light with a wavelength of 365 nm and light with a wavelength of 405 nm.

The present invention relates to a mask blank for manufacturing an FPD device having at least a semi-transparent film having a function of adjusting the amount of transmission on a transparent substrate, and the mask blank has a high transmittance for exposure light. Also, it is possible to provide a mask blank having a semi-transparent film that can suppress the in-plane distribution of transmittance for a plurality of wavelengths of exposure light, and can also suppress transmittance fluctuations due to changes in film thickness.

Further, according to the present invention, even when the transmittance for exposure light is increased, it is possible to suppress the in-plane distribution of transmittance for multiple wavelengths of the exposure light, and it is also possible to suppress transmittance fluctuations due to film thickness variations. A transfer mask having a semi-transparent film pattern and a method for manufacturing the transfer mask can be provided. Further, the present invention can provide a method for manufacturing a display device using such a transfer mask.

FIG. 1 is a schematic cross-sectional view showing a film structure of a mask blank according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing another film configuration of the mask blank according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a manufacturing process of a transfer mask according to an embodiment of the present invention. It is a cross-sectional schematic diagram which shows another manufacturing process of the transfer mask of embodiment of this invention. A diagram showing an example of the relationship between the film thickness and transmittance of a semi-transparent film when the extinction coefficient k is changed at a predetermined refractive index n for light with a wavelength of 405 nm (h line) derived from simulation results. It is. FIG. 3 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Example 1, which was derived from simulation results. FIG. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Example 2, which was derived from simulation results. FIG. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Example 3, which was derived from simulation results. FIG. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of a semi-transparent film in Comparative Example 1, which was derived from simulation results. FIG. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of a semi-transparent film in Comparative Example 2, which was derived from simulation results. Relationship between refractive index n and extinction coefficient k that can suppress in-plane transmittance distribution and transmittance fluctuation due to film thickness variation, and refraction in Examples 1 to 3 and Comparative Examples 1 and 2 derived from simulation results. It is a figure showing rate n and extinction coefficient k. FIG. 2 is a diagram for explaining a gray tone mask having a semi-transparent film (semi-transparent film), in which (1) is a partial plan view and (2) is a partial cross-sectional view.

First, the circumstances leading to the completion of the present invention will be described. The present inventor has discovered that even when the transmittance for exposure light including wavelengths in the ultraviolet region (hereinafter sometimes simply referred to as "exposure light") is increased, the transmittance for multiple wavelengths of exposure light is in-plane. We conducted extensive research on the structure of a mask blank that has a semi-transparent film that can suppress the distribution and also suppress transmittance fluctuations due to changes in film thickness.

In a mask blank comprising a semi-transparent film on a transparent substrate, the refractive index n, extinction coefficient k, and film thickness of the semi-transparent film are determined based on its function as a transmittance adjustment film for exposure light containing wavelengths in the ultraviolet region. subject to restrictions. Therefore, it is necessary to control the refractive index n and extinction coefficient k of the semi-transparent film so that they fall within predetermined ranges.

Here, the present inventor has determined that the transmittance is 20% or more for light with a wavelength of 365 nm (i-line) and light with a wavelength of 405 nm (h-line) among exposure light including wavelengths in the ultraviolet region. An optical study on the relationship between the refractive index n and extinction coefficient k of a semi-transparent film in order to satisfy the above requirements and suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light, as well as suppress transmittance fluctuations due to film thickness fluctuations. A simulation was performed. By satisfying these desired relationships at the i-line and h-line, if the reference wavelength for designing the transmittance of a semi-transparent film is selected from the wavelength range from the i-line to the h-line, the semi-transparent film will be The transmittance as designed can be obtained at the reference wavelength, the in-plane distribution can be suppressed at any wavelength from the i-line to the h-line, and the transmittance fluctuation due to film thickness variation can be suppressed. Furthermore, similar effects can be expected for other wavelengths in the ultraviolet region.
In the optical simulation, each value of the refractive index n and extinction coefficient k of the semi-transparent film was determined with the refractive index n in the range of 1.80 to 3.00 and the extinction coefficient k in the range of 0.00 to 0.80. We investigated the relationship between the thickness of the semi-transparent film and the transmittance (and reflectance) while changing the .

Figure 5 shows an example of the relationship between the film thickness and transmittance of a semi-transparent film when the extinction coefficient is changed at a predetermined refractive index, derived from simulation results, for light with a wavelength of 405 nm (H line). FIG. Specifically, in FIG. 5, when the refractive index n is 2.40 and the extinction coefficient k is 0.10, 0.16, 0.30, 0.40, and 0.50, the curve A1 It is shown as A5.
For each of the curves A1 to A5, it was examined whether the film thickness dependence of the transmittance was within an acceptable range (for example, whether the transmittance variation was within 2% when the film thickness changed 5 nm). As a result, in curves A2 to A4, the dependence of transmittance on film thickness was within the permissible range, and in curves A1 and A5, it was outside the permissible range.
Table 1 shows the relationship between film thickness and transmittance for curves A1, A3, and A5.

As shown in Table 1, in curve A3, the dependence of the transmittance on the film thickness is very good, and as shown in Figure 5, the change in the transmittance is very small in the range around the film thickness of 50 nm. , had a substantially flat area. On the other hand, in curves A1 and A5, there were places where the change in transmittance exceeded 2% at a change in film thickness of 5 nm, which was outside the allowable range. Further, the curve A2 represents the lower limit value of the extinction coefficient k at which the film thickness dependence of transmittance falls within an acceptable range, and the curve A4 represents the lower limit value of the extinction coefficient k at which the film thickness dependence of transmittance falls within an allowable range. It was found that this represents the upper limit of .

Then, by changing the values of the refractive index n and the extinction coefficient k, we performed the above-mentioned transmittance simulation and organized the relationship between the refractive index n and the extinction coefficient k that would keep the film thickness dependence of the transmittance within an acceptable range. . Further, a similar simulation was performed for light with a wavelength of 365 nm (i-line), and the relationship between the refractive index n and the extinction coefficient k, in which the film thickness dependence of the transmittance is within an acceptable range, was summarized. As a result, the transmittance for light with a wavelength of 365 nm (i-line) and light with a wavelength of 405 nm (h-line) satisfies the requirement of 20% or more, and the dependence of transmittance on film thickness is within the allowable range. The relational expressions for the refractive index n and extinction coefficient of the transmission film are as follows (see FIG. 11).
(Formula 1) k≧0.282×n−0.514
(Formula 2) k≦0.500×n+0.800

That is, the refractive index n and extinction coefficient k for light with a wavelength of 365 nm in the semi-transparent film, and the refractive index n and extinction coefficient k for light with a wavelength of 405 nm, both have the relationship of (Equation 1) and (Equation 2). The present inventor has discovered that when satisfying the above conditions, even if the transmittance for exposure light is increased, it is possible to suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light, and also suppress transmittance fluctuations due to film thickness variations. found.

Equations (1) and (2) in FIG. 11 correspond to the equal parts of (Equation 1) and (Equation 2) described above. In addition, in FIG.
Formula (3) k=0.370×n-0.590
is obtained by plotting the values of n and k, in which the change in transmittance is very small with respect to film thickness variation and has a substantially flat region.

Regarding the film thickness dependence of transmittance, the present inventor speculates as follows.
The thickness of the semi-transparent membrane and the transmittance are inversely proportional (inversely proportional), and normally, as the thickness of the semi-transparent membrane increases, the transmittance decreases (the graph becomes downward-sloping).
In the present invention, the phenomenon in which the transmittance fluctuation is suppressed even if the film thickness of the semi-transparent film changes is that when the film thickness changes before and after the target transmittance (set film thickness), the transmittance of the film changes. It should fluctuate in inverse proportion to the change in thickness, but the change in reflectance compensates for the change in transmittance. Therefore, a balance between transmittance and reflectance is achieved, and a phenomenon occurs in which the transmittance changes gradually with respect to changes in film thickness, and the changes in transmittance with respect to changes in film thickness become small.
The present invention has been made as a result of the above-mentioned intensive studies.

Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the following embodiments are examples of embodying the present invention, and do not limit the present invention within its scope.

FIG. 1 is a schematic diagram showing the film structure of a mask blank 10 of this embodiment. The mask blank 10 shown in FIG. 1 includes a transparent substrate 20, a semi-transparent film 30 formed on the transparent substrate 20, and an etching mask film 40 formed on the semi-transparent film 30.

FIG. 2 is a schematic diagram showing a film structure of a mask blank 10 according to another embodiment. The mask blank 10 shown in FIG. 2 includes a transparent substrate 20 and a semi-transparent film 30 formed on the transparent substrate 20.

Hereinafter, the transparent substrate 20, semi-transparent film 30, and etching mask film 40 that constitute the mask blank 10 for manufacturing a display device of this embodiment will be specifically explained.

<Transparent substrate 20>
The transparent substrate 20 is transparent to exposure light. The light-transmitting substrate 20 has a transmittance of 85% or more, preferably 90% or more for exposure light, assuming that there is no surface reflection loss. The transparent substrate 20 is made of a material containing silicon and oxygen, and is made of a glass material such as synthetic quartz glass, quartz glass, aluminosilicate glass, soda lime glass, and low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.). Can be configured. When the transparent substrate 20 is made of low thermal expansion glass, it is possible to suppress a change in the position of the semi-transparent film pattern 30a due to thermal deformation of the transparent substrate 20. Further, the light-transmitting substrate 20 used for display device applications is generally a rectangular substrate. Specifically, it is possible to use a translucent substrate 20 whose main surface (the surface on which the semi-transparent film 30 is formed) has a short side length of 300 mm or more. In the mask blank 10 of this embodiment, it is possible to use a large-sized light-transmitting substrate 20 in which the length of the short side of the main surface is 300 mm or more. Using the mask blank 10 of this embodiment, a transfer mask 100 having a transfer pattern including a fine semi-transparent film pattern 30a having a width and/or diameter of less than 2.0 μm on a transparent substrate 20, for example, is provided. can be manufactured. By using the transfer mask 100 of this embodiment, it is possible to stably transfer a transfer pattern including a predetermined fine pattern onto a transfer target.

<Semi-transparent membrane 30>
The semi-transparent film 30 of the mask blank 10 for manufacturing a display device of the present embodiment (hereinafter sometimes simply referred to as "the mask blank 10 of the present embodiment") is made of metal, silicon (Si), and nitrogen (N). It is preferable that the material is made of a material containing. The metal is preferably a transition metal. Suitable transition metals include molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), and zirconium (Zr), with titanium and molybdenum being particularly preferable.

The semi-transparent film 30 contains nitrogen. Nitrogen, which is a light elemental component, has the effect of not lowering the refractive index n and extinction coefficient k, compared to oxygen, which is also a light elemental component. In order for the semi-transparent film 30 to exhibit the above-mentioned effects, it is desirable that the extinction coefficient k of the semi-transparent film 30 be below the upper limit value described below, and the refractive index n should be greater than the lower limit value described below. By containing nitrogen in the semi-transparent film 30, it becomes easier to adjust the refractive index n and extinction coefficient k to desired values. Further, the content of nitrogen contained in the semi-transparent film 30 is preferably 30 atomic % or more, and more preferably 40 atomic % or more. On the other hand, the nitrogen content is preferably 60 atomic % or less, more preferably 55 atomic % or less. By increasing the nitrogen content in the semi-transparent film 30, it is possible to prevent the transmittance of exposure light from becoming excessively high.

The semi-transparent membrane 30 can contain oxygen within a range that does not deteriorate the performance of the semi-transparent membrane 30. Oxygen, which is a light elemental component, has a greater effect of lowering the refractive index n and extinction coefficient k than nitrogen, which is also a light elemental component. However, if the semi-transparent film 30 has a high oxygen content, it may have an adverse effect on obtaining a near-vertical fine pattern cross section and high mask cleaning resistance. Therefore, the oxygen content of the semi-transparent film 30 is preferably 7 atomic % or less, more preferably 5 atomic % or less. The semi-permeable membrane 30 may not contain oxygen.

In addition to the above-mentioned oxygen and nitrogen, the semi-transparent film 30 may contain other light element components such as carbon and helium for the purpose of reducing film stress and/or controlling the wet etching rate. .

The atomic ratio of transition metal and silicon contained in the semi-transparent film 30 is preferably in the range of transition metal:silicon=1:3 to 1:15. Within this range, the effect of suppressing a drop in wet etching rate during pattern formation of the semi-transparent film 30 can be increased. Further, the cleaning resistance of the semi-transparent membrane 30 can be increased, and the transmittance can also be easily increased. From the viewpoint of increasing the cleaning resistance of the semi-transparent film 30, the atomic ratio of transition metal to silicon (transition metal: silicon) contained in the semi-transparent film 30 is preferably in the range of 1:5 to 1:15.

Preferably, this semi-transparent membrane 30 is composed of a single layer. The semi-transparent film 30 composed of a single layer is preferable because an interface is less likely to be formed in the semi-transparent film 30 and the cross-sectional shape can be easily controlled. On the other hand, the semi-transparent film 30 may be any film that can be substantially regarded as optically a single layer, and may be a compositionally graded film whose composition changes continuously in the thickness direction. Note that the refractive index n and extinction coefficient k of the semi-transparent film 30 in the case of a compositionally graded film are derived by considering the entire film as an optically uniform single layer film.
The thickness of the semi-transparent film 30 is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 70 nm or less, from the viewpoint of the cross-sectional shape during patterning and the etching time required for patterning. Further, from the viewpoint of forming a film according to the designed film thickness, the thickness of the semi-transparent film 30 is preferably 20 nm or more, more preferably 25 nm or more, and even more preferably 30 nm or more.

<<Transmittance and phase difference of semi-transparent membrane 30>>
The transmittance and phase difference of the semi-transparent film 30 with respect to exposure light satisfy values necessary for the semi-transparent film 30. The transmittance of the semi-transparent film 30 is preferably 20% or more and 70% or less, more preferably 25% or more and 65% or less, and even more preferably 30% for light with a wavelength of 365 nm (i-line). 60% or less. Unless otherwise specified, the transmittance in this specification refers to a value calculated using the transmittance of a light-transmitting substrate as a reference (100%).
Further, the phase difference of the semi-transparent film for light with a wavelength of 365 nm is preferably 0 degrees or more and 120 degrees or less, more preferably 0 degrees or more and 90 degrees or less, and preferably 0 degrees or more and 60 degrees or less. More preferred.

That is, when the exposure light is composite light including light in the wavelength range of 313 nm or more and 436 nm or less, the semi-transparent film 30 has the above-mentioned transmittance for light with a wavelength of 365 nm (i-line) included in the wavelength range. and has a phase difference. By having such characteristics for the i-line, when composite light including the i-line, h-line, and g-line is used as exposure light, the transmittance for the g-line or h-line will be similar. You can expect good results.

Transmittance and phase difference can be measured using a phase shift amount measuring device or the like.

The refractive index n and extinction coefficient k for light with a wavelength of 365 nm in the semi-transparent film 30 and the refractive index n and extinction coefficient k for light with a wavelength of 405 nm both satisfy the relationships of (Formula 1) and (Formula 2). Preferably.
(Formula 1) k≧0.282×n−0.514
(Formula 2) k≦0.500×n+0.800

Further, it is preferable that the refractive index n and extinction coefficient k of the semi-transparent film 30 for light with a wavelength of 436 nm (g-line) also satisfy the relationships of (Formula 1) and (Formula 2).

The extinction coefficient k of the semi-transparent film 30 for light with a wavelength of 365 nm is preferably larger than 0, and more preferably 0.05 or more. On the other hand, the extinction coefficient k of the semi-transparent film 30 for light with a wavelength of 365 nm is preferably 1.0 or less, more preferably 0.8 or less.
The refractive index n of the semi-transparent film 30 for light with a wavelength of 365 nm is preferably 2.0 or more, more preferably 2.1 or more. On the other hand, the refractive index n of the semi-transparent film 30 for light with a wavelength of 365 nm is preferably 3.0 or less, more preferably 2.8 or less.

The reflectance (surface reflectance) of the semi-transparent film 30 is 40% or less in the wavelength range of 365 nm to 436 nm, preferably 35% or less. The back surface reflectance of the semi-transparent film 30 is preferably 25% or less in the wavelength range of 365 nm to 436 nm, and preferably 15% or less.

The front surface reflectance and the back surface reflectance can be measured using a spectrophotometer or the like.

The semi-transparent film 30 can be formed by a known film forming method such as a sputtering method.

<Etching mask film 40>
It is preferable that the mask blank 10 for manufacturing a display device of the present embodiment includes an etching mask film 40 having different etching selectivity with respect to the semi-transparent film 30 on the semi-transparent film 30.

The etching mask film 40 is disposed above the semi-transparent film 30 and is made of a material that has etching resistance to an etching solution that etches the semi-transparent film 30 (has different etching selectivity from the semi-transparent film 30). Further, the etching mask film 40 can have a function of blocking transmission of exposure light. Furthermore, the etching mask film 40 reduces the film surface reflectance of the semi-transparent film 30 to light incident from the semi-transparent film 30 side so that it is 15% or less in the wavelength range of 350 nm to 436 nm. It may have a function.

The etching mask film 40 is preferably made of a chromium-based material containing chromium (Cr). More preferably, the etching mask film 40 is made of a material that contains chromium and does not substantially contain silicon. Substantially not containing silicon means that the silicon content is less than 2% (excluding the compositionally gradient region at the interface between the semi-transparent film 30 and the etching mask film 40). More specifically, the chromium-based material is chromium (Cr), or a material containing chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C). can be mentioned. Examples of chromium-based materials include materials that include chromium (Cr) and at least one of oxygen (O), nitrogen (N), and carbon (C), and further include fluorine (F). . For example, materials constituting the etching mask film 40 include Cr, CrO, CrN, CrF, CrCO, CrCN, CrON, CrCON, and CrCONF.

The etching mask film 40 can be formed by a known film forming method such as a sputtering method.

When the etching mask film 40 has a function of blocking transmission of exposure light, the optical density with respect to the exposure light is preferably 3 or more, more preferably, in the portion where the semi-transparent film 30 and the etching mask film 40 are laminated. It is 3.5 or more, more preferably 4 or more. Optical density can be measured using a spectrophotometer, an OD meter, or the like.

The etching mask film 40 can be a single film with a uniform composition depending on the function. Moreover, the etching mask film 40 can be made into a plurality of films having different compositions. Further, the etching mask film 40 can be a single film whose composition changes continuously in the thickness direction.

Note that the mask blank 10 of this embodiment shown in FIG. 1 includes an etching mask film 40 on a semi-transparent film 30. The mask blank 10 of this embodiment includes a structure in which an etching mask film 40 is provided on a semi-transparent film 30 and a resist film is provided on the etching mask film 40.

<Method for manufacturing mask blank 10>
Next, a method for manufacturing the mask blank 10 of the embodiment shown in FIG. 1 will be described. The mask blank 10 shown in FIG. 1 is manufactured by performing the following semi-transparent film forming process and etching mask film forming process. The mask blank 10 shown in FIG. 2 is manufactured by a semi-transparent film forming process.

Each step will be explained in detail below.

<<Semi-transparent membrane formation process>>
First, a transparent substrate 20 is prepared. The transparent substrate 20 is selected from synthetic silica glass, quartz glass, aluminosilicate glass, soda lime glass, low thermal expansion glass (SiO ₂ -TiO ₂ glass, etc.), and the like, as long as it is transparent to exposure light. It can be constructed of glass material.

Next, a semi-transparent film 30 is formed on the transparent substrate 20 by sputtering.

The semi-transparent film 30 can be formed using a predetermined sputtering target in a predetermined sputtering gas atmosphere. The predetermined sputter target is, for example, a metal silicide target containing metal and silicon, which are the main components of the material constituting the semi-transparent film 30, or a metal silicide target containing metal, silicon, and nitrogen. . The predetermined sputtering gas atmosphere is, for example, a sputtering gas atmosphere consisting of an inert gas containing at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas, or the above inert gas, The sputtering gas atmosphere is made of a mixed gas containing nitrogen gas and optionally a gas selected from the group consisting of oxygen gas, carbon dioxide gas, nitrogen monoxide gas, and nitrogen dioxide gas. The semi-transparent film 30 can be formed in a state where the gas pressure in the film forming chamber during sputtering is 0.3 Pa or more and 2.0 Pa or less, preferably 0.43 Pa or more and 0.9 Pa or less. Side etching during pattern formation can be suppressed and a high etching rate can be achieved.

The composition and thickness of the semi-transparent film 30 are adjusted so that the semi-transparent film 30 has the above-mentioned transmittance and phase difference. The composition of the semi-transparent film 30 can be controlled by the content ratio of elements constituting the sputtering target (for example, the ratio of the metal content to the silicon content), the composition and flow rate of the sputtering gas, and the like. The thickness of the semi-transparent film 30 can be controlled by sputtering power, sputtering time, and the like. Further, the semi-transparent film 30 is preferably formed using an in-line sputtering device. If the sputtering device is an in-line sputtering device, the thickness of the semi-transparent film 30 can also be controlled by the substrate conveyance speed. In this way, the semi-transparent film 30 contains metal, silicon, and nitrogen, and the refractive index n and extinction coefficient k of the semi-transparent film 30 satisfy the desired relationship (refractive index n and extinction coefficient k for light with a wavelength of 365 nm). Control is performed so that the extinction coefficient k, the refractive index n and the extinction coefficient k for light with a wavelength of 405 nm all satisfy the relationships of the above (Formula 1) and the above (Formula 2).

<<Surface treatment process>>
When the semi-transparent film 30 contains oxygen, surface treatment is performed to adjust the state of surface oxidation of the semi-transparent film 30 in order to suppress penetration of the etching solution due to the presence of metal oxides on the surface of the semi-transparent film 30. You may perform a process. Note that when the semi-transparent film 30 is made of a metal silicide nitride containing metal, silicon, and nitrogen, the content of transition metal oxide is smaller than that of the above-mentioned metal silicide material containing oxygen. Therefore, when the material of the semi-transparent film 30 is metal silicide nitride, the above surface treatment step may or may not be performed.

Examples of the surface treatment process for adjusting the surface oxidation state of the semi-transparent membrane 30 include a method of surface treatment with an acidic aqueous solution, a method of surface treatment with an alkaline aqueous solution, a method of surface treatment with a dry treatment such as ashing, etc. .

In this way, the mask blank 10 of this embodiment can be obtained.

<<Etching mask film formation process>>
The mask blank 10 of this embodiment can further include an etching mask film 40. The following etching mask film forming process is further performed. Note that the etching mask film 40 is preferably made of a material that contains chromium and does not substantially contain silicon.

After the semi-transparent film forming step, a surface treatment for adjusting the surface oxidation state of the surface of the semi-transparent film 30 is performed as necessary, and then an etching mask film 40 is formed on the semi-transparent film 30 by a sputtering method. . The etching mask film 40 is preferably formed using an in-line sputtering device. When the sputtering device is an in-line sputtering device, the thickness of the etching mask film 40 can also be controlled by the transport speed of the transparent substrate 20.

The etching mask film 40 is formed using an inert gas sputtering target containing chromium or a chromium compound (chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxynitride carbide, chromium oxynitride carbide, etc.). The sputtering can be carried out in a sputtering gas atmosphere consisting of a mixture of an inert gas and an active gas, or a sputtering gas atmosphere consisting of a mixed gas of an inert gas and an active gas. The inert gas can include, for example, at least one selected from the group consisting of helium gas, neon gas, argon gas, krypton gas, and xenon gas. The active gas may include at least one selected from the group consisting of oxygen gas, nitrogen gas, nitrogen monoxide gas, nitrogen dioxide gas, carbon dioxide gas, hydrocarbon gas, and fluorine gas. Examples of the hydrocarbon gas include methane gas, butane gas, propane gas, and styrene gas.

When the etching mask film 40 is composed of a single film with a uniform composition, the above-described film formation process is performed only once without changing the composition and flow rate of the sputtering gas. When the etching mask film 40 is composed of a plurality of films having different compositions, the above-described film formation process is performed multiple times by changing the composition and flow rate of the sputtering gas for each film formation process. When the etching mask film 40 is composed of a single film whose composition changes continuously in the thickness direction, the above-described film formation process can be performed one by one while changing the composition and flow rate of the sputtering gas with the elapsed time of the film formation process. Do it only once.

In this way, the mask blank 10 of this embodiment having the etching mask film 40 can be obtained.

Note that since the mask blank 10 shown in FIG. 1 includes the etching mask film 40 on the semi-transparent film 30, an etching mask film forming step is performed when manufacturing the mask blank 10. In addition, when manufacturing the mask blank 10 that includes the etching mask film 40 on the semi-transparent film 30 and the resist film on the etching mask film 40, the resist film is formed on the etching mask film 40 after the etching mask film forming step. Form. Furthermore, when manufacturing the mask blank 10 shown in FIG. 2 that includes a resist film on the semi-transparent film 30, the resist film is formed after the semi-transparent film forming step.

In the mask blank 10 of the embodiment shown in FIG. 1, an etching mask film 40 is formed on a semi-transparent film 30. Further, in the mask blank 10 of the embodiment shown in FIG. 2, a semi-transparent film 30 is formed. In either case, the refractive index n and extinction coefficient k of the semi-transparent film 30 satisfy the desired relationship (the refractive index n and extinction coefficient k for light with a wavelength of 365 nm, and the refractive index n and extinction coefficient k for light with a wavelength of 405 nm). Control is performed such that the coefficient k satisfies the relationships of the above (Formula 1) and the above (Formula 2).

The mask blank 10 of the embodiment shown in FIGS. 1 and 2 has a refractive index n and an extinction coefficient k that satisfy a desired relationship (refractive index n and extinction coefficient k for light with a wavelength of 365 nm, and The semi-transparent film 30 has a refractive index n and an extinction coefficient k that both satisfy the relationships of (Formula 1) and (Formula 2) above. By using the mask blank 10 of the embodiment, even when the transmittance for exposure light is increased, it is possible to suppress the in-plane distribution of transmittance for a plurality of wavelengths of the exposure light, and also to suppress transmittance fluctuations due to film thickness variations. It is possible to manufacture a transfer mask 100 that can accurately transfer the semi-transparent film pattern 30a that can suppress the phenomenon.

<Method for manufacturing transfer mask 100>
Next, a method for manufacturing the transfer mask 100 of this embodiment will be described. This transfer mask 100 has the same technical characteristics as the mask blank 10. Matters regarding the transparent substrate 20, semi-transparent film 30, and etching mask film 40 in the transfer mask 100 are the same as those in the mask blank 10.

FIG. 3 is a schematic diagram showing a method for manufacturing the transfer mask 100 of this embodiment. FIG. 4 is a schematic diagram showing another method of manufacturing the transfer mask 100 of this embodiment.

<<Method for manufacturing transfer mask 100 shown in FIG. 3>
The method for manufacturing the transfer mask 100 shown in FIG. 3 is a method for manufacturing the transfer mask 100 using the mask blank 10 shown in FIG. 1. The method for manufacturing the transfer mask 100 shown in FIG. 3 includes the steps of preparing the mask blank 10 shown in FIG. 1, forming a resist film on the etching mask film 40, and using the resist film pattern formed from the resist film as a mask. wet etching the etching mask film 40 to form a transfer pattern (first etching mask film pattern 40a) on the semi-transparent film 30; The method includes a step of wet-etching the semi-transparent film 30 using the etching mask film pattern 40a) as a mask to form a transfer pattern on the semi-transparent film 30. Note that the transfer pattern in this specification is obtained by patterning at least one optical film formed on the transparent substrate 20. The above optical film can be a semi-transparent film 30 and/or an etching mask film 40, and may further include other films (a light-shielding film, a film for suppressing reflection, a conductive film, etc.). Good too. That is, the transfer pattern may include a patterned semi-transparent film and/or an etching mask film, and may further include other patterned films.

Specifically, in the method for manufacturing the transfer mask 100 shown in FIG. 3, a resist film is formed on the etching mask film 40 of the mask blank 10 shown in FIG. Next, a resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film (see FIG. 3A, step of forming the first resist film pattern 50). Next, the etching mask film 40 is wet-etched using the resist film pattern 50 as a mask to form a first etching mask film pattern 40a on the semi-transparent film 30 (see FIG. 3(b)). Step of forming etching mask film pattern 40a). Next, using the first etching mask film pattern 40a as a mask, the semi-transparent film 30 is wet-etched to form a semi-transparent film pattern 30a on the transparent substrate 20 (see FIG. 3(c), Step of forming film pattern 30a). After that, the process may further include a step of forming a second resist film pattern 60 and a step of forming a second etching mask film pattern 40b (see FIGS. 3(d) and (e)).

More specifically, in the step of forming the first resist film pattern 50, a resist film is first formed on the etching mask film 40 of the mask blank 10 of this embodiment shown in FIG. The resist film material used is not particularly limited. The resist film may be one that is sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Further, the resist film may be either positive type or negative type.

Thereafter, a desired pattern is drawn on the resist film using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm. The pattern drawn on the resist film is the pattern formed on the semi-transparent film 30. Patterns drawn on the resist film include line and space patterns and hole patterns.

Thereafter, the resist film is developed with a predetermined developer to form a first resist film pattern 50 on the etching mask film 40, as shown in FIG. 3(a).

<<<Step of forming first etching mask film pattern 40a >>>
In the step of forming the first etching mask film pattern 40a, first, the etching mask film 40 is etched using the first resist film pattern 50 as a mask to form the first etching mask film pattern 40a. The etching mask film 40 can be formed from a chromium-based material containing chromium (Cr). The etching solution 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 ceric ammonium nitrate and perchloric acid may be used.

Thereafter, the first resist film pattern 50 is removed using a resist removal solution or by ashing, as shown in FIG. 3(b). In some cases, the next step of forming the semi-transparent film pattern 30a may be performed without peeling off the first resist film pattern 50.

<<<Step of forming semi-transparent film pattern 30a>>>
In the step of forming the semi-transparent film pattern 30a, the semi-transparent film 30 is wet-etched using the first etching mask film pattern 40a as a mask to form the semi-transparent film pattern 30a as shown in FIG. 3(c). do. Examples of the semi-transparent film pattern 30a include a line and space pattern and a hole pattern. The etching solution for etching the semi-transparent film 30 is not particularly limited as long as it can selectively etch the semi-transparent film 30. Examples include an etching solution containing ammonium hydrogen fluoride and hydrogen peroxide, and an etching solution containing ammonium fluoride, phosphoric acid, and hydrogen peroxide.

In order to improve the cross-sectional shape of the semi-transparent film pattern 30a, wet etching is performed for a longer time (over-etching time) than the time it takes for the transparent substrate 20 to be exposed in the semi-transparent film pattern 30a (just etching time). It is preferable to do so. Considering the influence on the light-transmitting substrate 20, the over-etching time is preferably within the just-etching time plus 20% of the just-etching time, and 10% of the just-etching time. It is more preferable to set it within the time period including the time of .

<<<Step of forming second resist film pattern 60 >>>
In the step of forming the second resist film pattern 60, first, a resist film is formed to cover the first etching mask film pattern 40a. The resist film material used is not particularly limited. For example, it may be one that is sensitive to laser light having any wavelength selected from the wavelength range of 350 nm to 436 nm, which will be described later. Further, the resist film may be either positive type or negative type.

Thereafter, a desired pattern is drawn on the resist film using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm. The patterns drawn on the resist film include a light-shielding band pattern that blocks light from the outer peripheral area of the area where the semi-transparent film pattern 30a is formed, and a light-shielding band pattern that blocks light from the central portion of the semi-transparent film pattern 30a. Note that, depending on the transmittance of the semi-transparent film 30 to exposure light, the pattern drawn on the resist film may be a pattern without a light-shielding band pattern that blocks light from the center of the semi-transparent film pattern 30a.

Thereafter, the resist film is developed with a predetermined developer to form a second resist film pattern 60 on the first etching mask film pattern 40a, as shown in FIG. 3(d).

<<<Step of forming second etching mask film pattern 40b >>>
In the step of forming the second etching mask film pattern 40b, the first etching mask film pattern 40a is etched using the second resist film pattern 60 as a mask to form a second etching mask film pattern 40b as shown in FIG. 3(e). An etching mask film pattern 40b is formed. The first etching mask film pattern 40a may be formed of a chromium-based material containing chromium (Cr). The etching solution for etching the first etching mask film pattern 40a is not particularly limited as long as it can selectively etch the first etching mask film pattern 40a. For example, an etching solution containing ceric ammonium nitrate and perchloric acid may be used.

Thereafter, the second resist film pattern 60 is removed using a resist removal solution or by ashing.

In this way, the transfer mask 100 can be obtained. That is, in the transfer mask 100 according to the present embodiment, a transfer pattern (semi-transparent film pattern 30a) is formed on the semi-transparent film 30, and a pattern different from the transfer pattern (second etching mask film pattern) is formed on the etching mask film 40. 40b) is formed.

Note that in the above description, the case where the etching mask film 40 has a function of blocking transmission of exposure light has been described. In the case where the etching mask film 40 simply has the function of a hard mask when etching the semi-transparent film 30, in the above description, the process of forming the second resist film pattern 60 and the process of forming the second etching mask film pattern The forming step 40b is not performed. In this case, after the step of forming the semi-transparent film pattern 30a, the first etching mask film pattern 40a is peeled off to produce the transfer mask 100. That is, the transfer pattern that the transfer mask 100 has may include only the semi-transparent film pattern 30a.

According to the method for manufacturing the transfer mask 100 of this embodiment, since the mask blank 10 shown in FIG. It is possible to form a semi-transparent film pattern 30a that can suppress in-plane distribution and also suppress transmittance fluctuation due to film thickness fluctuation. Therefore, it is possible to manufacture a transfer mask 100 that can accurately transfer a transfer pattern including a high-definition semi-transparent film pattern 30a. The transfer mask 100 manufactured in this manner can correspond to miniaturization of line and space patterns and/or contact holes.

<<Method for manufacturing transfer mask 100 shown in FIG. 4>>
The method for manufacturing the transfer mask 100 shown in FIG. 4 is a method for manufacturing the transfer mask 100 using the mask blank 10 shown in FIG. 2. The method for manufacturing the transfer mask 100 shown in FIG. 4 includes the steps of preparing the mask blank 10 shown in FIG. 2, forming a resist film on the semi-transparent film 30, and using the resist film pattern formed from the resist film as a mask. and wet-etching the semi-transparent film 30 to form a transfer pattern on the semi-transparent film 30.

Specifically, in the method for manufacturing the transfer mask 100 shown in FIG. 4, a resist film is formed on the mask blank 10. Next, a resist film pattern 50 is formed by drawing and developing a desired pattern on the resist film (FIG. 4A, step of forming the first resist film pattern 50). Next, the semi-transparent film 30 is wet-etched using the resist film pattern 50 as a mask to form a semi-transparent film pattern 30a on the transparent substrate 20 (FIGS. 4(b) and 4(c), Step of forming film pattern 30a).

More specifically, in the step of forming a resist film pattern, a resist film is first formed on the semi-transparent film 30 of the mask blank 10 of this embodiment shown in FIG. The resist film material used is the same as described above. Note that, if necessary, before forming the resist film, the semi-transparent film 30 can be subjected to surface modification treatment in order to improve the adhesion between the semi-transparent film 30 and the resist film. Similarly to the above, after forming a resist film, a desired pattern is drawn on the resist film using a laser beam having any wavelength selected from the wavelength range of 350 nm to 436 nm. Thereafter, the resist film is developed with a predetermined developer to form a resist film pattern 50 on the semi-transparent film 30, as shown in FIG. 4(a).

<<<Step of forming semi-transparent film pattern 30a>>>
In the step of forming the semi-transparent film pattern 30a, the semi-transparent film 30 is etched using the resist film pattern as a mask to form the semi-transparent film pattern 30a as shown in FIG. 4(b). The etching solution and over-etching time for etching the semi-transparent film pattern 30a and the semi-transparent film 30 are the same as those described in the embodiment shown in FIG. 3 above.

Thereafter, the resist film pattern 50 is removed using a resist removal solution or by ashing (FIG. 4(c)).

In this way, the transfer mask 100 can be obtained. That is, in the transfer mask 100 according to this embodiment, a transfer pattern (semi-transparent film pattern 30a) is formed on the semi-transparent film 30. Note that, although the transfer pattern of the transfer mask 100 according to this embodiment is composed of only the semi-transparent film pattern 30a, it may further include other film patterns. Other films include, for example, a film that suppresses reflection, a conductive film, and the like.

According to the method for manufacturing the transfer mask 100 of this embodiment, since the mask blank 10 shown in FIG. 2 is used, even when the transmittance for exposure light is increased, the transmittance for multiple wavelengths of the exposure light is It is possible to form a semi-transparent film pattern 30a that can suppress in-plane distribution and also suppress transmittance fluctuation due to film thickness fluctuation. Therefore, it is possible to manufacture a transfer mask 100 that can accurately transfer a transfer pattern including a high-definition semi-transparent film pattern 30a. The transfer mask 100 manufactured in this manner can correspond to miniaturization of line and space patterns and/or contact holes.

<Display device manufacturing method>
A method for manufacturing the display device of this embodiment will be described. The method for manufacturing a display device of the present embodiment includes placing the transfer mask 100 of the present embodiment described above on a mask stage of an exposure device, and transferring the transfer pattern formed on the transfer mask 100 for manufacturing a display device. The method includes an exposure step of exposing and transferring onto a resist formed on a substrate for a display device.

Specifically, the method for manufacturing a display device according to the present embodiment includes a step of placing a transfer mask 100 manufactured using the above-described mask blank 10 on a mask stage of an exposure apparatus (mask placing step); The process includes a step (exposure step) of irradiating the transfer mask 100 with exposure light to expose and transfer the transfer pattern onto a photosensitive film (resist film) provided on a substrate for a display device. Each step will be explained in detail below.

<<Placement process>>
In the mounting process, the transfer mask 100 of this embodiment is mounted on a mask stage of an exposure device. Here, the transfer mask 100 is placed so as to face a resist film formed on a substrate for a display device via a projection optical system of an exposure device.

<<Pattern transfer process>>
In the pattern transfer step, the transfer mask 100 is irradiated with exposure light to transfer the transfer pattern including the semi-transparent film pattern 30a onto a resist film formed on a substrate for a display device. The exposure light is composite light including light of a plurality of wavelengths selected from a wavelength range of 313 nm to 436 nm. For example, the exposure light is preferably composite light containing at least one of i-line, h-line, and g-line, and more preferably composite light containing i-line and h-line. By using composite light as the exposure light, the intensity of the exposure light can be increased and throughput can be improved. Therefore, the manufacturing cost of the display device can be reduced.

According to the method for manufacturing a display device of this embodiment, it is possible to manufacture a high-definition display device that has high resolution and fine line-and-space patterns and/or contact holes.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited thereto.

(Example 1)
In order to manufacture the mask blank 10 of Example 1, first, a synthetic quartz glass substrate of 1214 size (1220 mm x 1400 mm) was prepared as the transparent substrate 20.

Thereafter, the synthetic quartz glass substrate was mounted on a tray (not shown) with its main surface facing downward, and was carried into a chamber of an in-line sputtering apparatus.

In order to form the semi-transparent film 30 on the main surface of the transparent substrate 20, first, a mixed gas composed of argon (Ar) gas and nitrogen ( _N2 ) gas was introduced into the first chamber. Then, using a first sputter target containing titanium and silicon (titanium:silicon=14:86), titanium silicide containing titanium, silicon, and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. Nitride was deposited. The thickness of the semi-transparent film 30 was set to 50 nm so that the transmittance of the semi-transparent film 30 to the i-line (365 nm) was 58%. In this way, a semi-transparent film 30 made of titanium silicide nitride and having a thickness of 50 nm was formed.

Next, the transparent substrate 20 with the semi-transparent film 30 was carried into the second chamber, and a mixed gas of argon (Ar) gas and nitrogen (N ₂ ) gas was introduced into the second chamber. Then, using a second sputter target made of chromium, chromium nitride (CrN) containing chromium and nitrogen was formed on the semi-transparent film 30 by reactive sputtering. Next, with a predetermined degree of vacuum in the third chamber, a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas is introduced, and reactive sputtering is performed using a third sputtering target made of chromium. Chromium carbide (CrC) containing chromium and carbon was formed on CrN. Finally, with the fourth chamber at a predetermined degree of vacuum, a mixed gas of argon (Ar) gas and methane (CH ₄ ) gas, and a mixed gas of nitrogen (N ₂ ) gas and oxygen (O ₂ ) gas is added. was introduced, and chromium carbide oxynitride (CrCON) containing chromium, carbon, oxygen, and nitrogen was formed on CrC by reactive sputtering using a fourth sputter target made of chromium. As described above, the etching mask film 40 having a laminated structure of a CrN layer, a CrC layer, and a CrCON layer was formed on the semi-transparent film 30.

In this way, a mask blank 10 was obtained in which a semi-transparent film 30 and an etching mask film 40 were formed on a transparent substrate 20.

Another semi-transparent film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film forming conditions as in Example 1 above. The refractive index n and extinction coefficient k at i-line (365 nm) and h-line (405 nm) were measured for this semi-transparent film. The refractive index n at i-line (365 nm) was 2.19, and the extinction coefficient k was 0.17. Further, the refractive index n at the h-line (405 nm) was 2.20, and the extinction coefficient k was 0.12.
FIG. 11 shows the relationship between the refractive index n and the extinction coefficient k, which can suppress the in-plane transmittance distribution and the transmittance fluctuation due to film thickness fluctuation, derived from the simulation results, and Examples 1 to 3, Comparative Example 1, 2 is a diagram showing the refractive index n and the extinction coefficient k in No. 2. FIG. As shown in the figure, the semi-transparent film 30 of Example 1 has a refractive index n and an extinction coefficient k at the i-line (365 nm), and a refractive index n and extinction coefficient k at the h-line (405 nm). Both were within the range defined by (Formula 1) and (Formula 2) described above.

Next, based on the refractive index n and extinction coefficient k of the semi-transparent film 30 of Example 1, the set film thickness is determined so that the transmittance of the semi-transparent film 30 for the i-line (365 nm) is 58%. , a simulation was conducted of the transmittance, phase difference, and reflectance of the semi-transparent film 30 when the film thickness of the semi-transparent film 30 was changed.
FIG. 6 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Example 1, which was derived from the simulation results. As shown in the figure, the semi-transparent film 30 of Example 1 has a thickness in the range of 39 nm to 60 nm (Fig. It was found that the film thickness dependence of the transmittance for i-line (365 nm) was within an acceptable range (transmittance fluctuation within 2% when the film thickness changed 5 nm) over the range of Δd of 6. Furthermore, it was found that the film thickness dependence of the transmittance for the H-line (405 nm) was within an acceptable range (transmittance variation within 2% with a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>
Regarding the surface of the semi-transparent film 30 of the mask blank 10 of Example 1, the transmittance and phase difference at i-line (365 nm) were measured using MPM-100 manufactured by Lasertec. To measure the transmittance and phase difference of the semi-transparent film 30, a thin film-coated substrate in which another semi-transparent film was formed on the main surface of another synthetic quartz glass substrate was used (see Example 2 below). , 3, and the same applies to Comparative Examples 1 and 2). As a result, the transmittance of the semi-transparent film 30 for i-line (365 nm) in Example 1 was 58%, and the phase difference was 55 degrees.
In addition, when we measured the transmittance for i-line (365 nm) and h-line (405 nm) at 11 x 11 measurement points on the reference plane, the transmittance variation was within 1% for both. All were within acceptable ranges.
In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (ammonia permeate (APM), 30° C., 5 minutes) six times, and the change in transmittance due to changes in the thickness of the semi-permeable membrane 30 was evaluated. did. As a result, the variations in transmittance for i-line (365 nm) and h-line (405 nm) were both within 1%, which was within an acceptable range, compared to before the alkali cleaning treatment. Note that this evaluation was performed on a semi-transparent film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film forming conditions. From the above results, the semi-transparent film 30 of Example 1 is a semi-transparent film 30 that can suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light and has extremely small fluctuations in transmittance due to changes in film thickness. I can say that.

<Transfer mask 100 and its manufacturing method>
A transfer mask 100 was manufactured using the mask blank 10 of Example 1 manufactured as described above. First, a photoresist film was coated on the etching mask film 40 of this mask blank 10 using a resist coater.

Thereafter, a photoresist film was formed through a heating and cooling process.

Thereafter, a photoresist film was drawn using a laser drawing device, and a resist film pattern having a hole pattern with a hole diameter of 1.5 μm was formed on the etching mask film 40 through a development and rinsing process.

Thereafter, using the resist film pattern as a mask, the etching mask film 40 was wet-etched with a chromium etching solution containing ceric ammonium nitrate and perchloric acid to form a first etching mask film pattern 40a.

Thereafter, using the first etching mask film pattern 40a as a mask, the semi-transparent film 30 is wet-etched using a titanium silicide etching solution prepared by diluting a mixed solution of ammonium hydrogen fluoride and hydrogen peroxide with pure water. A film pattern 30a was formed.

After that, the resist film pattern was peeled off.

Thereafter, a photoresist film was applied using a resist coating device so as to cover the first etching mask film pattern 40a.

Thereafter, a photoresist film was formed through a heating and cooling process.

Thereafter, a photoresist film was drawn using a laser drawing device, and through a development and rinsing process, a second resist film pattern 60 for forming a light-shielding zone was formed on the first etching mask film pattern 40a. .

Thereafter, using the second resist film pattern 60 as a mask, the first etching mask film pattern 40a formed in the transfer pattern formation area is wetted with a chromium etching solution containing ceric ammonium nitrate and perchloric acid. Etched.

Thereafter, the second resist film pattern 60 was peeled off.

In this way, on the transparent substrate 20, a semi-transparent film pattern 30a with a hole diameter of 1.5 μm is formed in the transfer pattern formation area, and a light-shielding structure consisting of a laminated structure of the semi-transparent film pattern 30a and the etching mask film pattern 40b is formed. A transfer mask 100 of Example 1 in which a band was formed was obtained.

The transfer mask 100 of Example 1 obtained as described above can suppress the in-plane distribution of the transmittance for a plurality of wavelengths of the exposure light even when the transmittance for the exposure light is increased. Since the mask blank 10 is manufactured using a semi-transparent film 30 that can suppress transmittance fluctuations due to film thickness fluctuations, the transmittance adjustment effect can be enhanced by increasing the transmittance of the exposure light, and it is possible to increase the transmittance adjustment effect by increasing the transmittance of the exposure light. The transfer mask 100 has a semi-transparent film pattern 30a that can suppress the in-plane distribution of transmittance for the transfer film, and can also suppress variations in transmittance due to variations in film thickness.

From the above, when the transfer mask 100 of Example 1 is set on the mask stage of an exposure device and exposed and transferred to a resist film on a substrate for a display device, a transfer pattern including a fine pattern of less than 2.0 μm is obtained. It can be said that it is possible to transfer with high precision.

(Example 2)
The mask blank 10 of Example 2 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transparent film 30 was changed as described below.
The method for forming the semi-transparent film 30 of Example 2 is as follows.
In order to form the semi-transparent film 30 on the main surface of the transparent substrate 20, first, a mixed gas composed of argon (Ar) gas and nitrogen ( _N2 ) gas was introduced into the first chamber. Then, using a first sputter target containing titanium and silicon (titanium: silicon = 19:81), titanium silicide containing titanium, silicon, and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. Nitride was deposited. The thickness of the semi-transparent film 30 was set to 50 nm so that the transmittance of the semi-transparent film 30 to the i-line (365 nm) was 44%. In this way, a semi-transparent film 30 made of titanium silicide nitride and having a thickness of 50 nm was formed.
Thereafter, in the same manner as in Example 1, an etching mask film 40 was formed.

Another semi-transparent film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film forming conditions as in Example 2 above. The refractive index n and extinction coefficient k at i-line (365 nm) and h-line (405 nm) were measured for this semi-transparent film. The refractive index n at i-line (365 nm) was 2.42, and the extinction coefficient k was 0.31. Further, the refractive index n at the h-line (405 nm) was 2.44, and the extinction coefficient k was 0.22.
As shown in FIG. 11, the semi-transparent film 30 of Example 2 has a refractive index n and an extinction coefficient k at the i-line (365 nm), and a refractive index n and extinction coefficient k at the h-line (405 nm). Both were within the range defined by (Formula 1) and (Formula 2) described above.

Next, based on the refractive index n and extinction coefficient k of the semi-transparent film 30 of Example 2, the set film thickness is determined so that the transmittance of the semi-transparent film 30 for the i-line (365 nm) is 44%. , a simulation was conducted of the transmittance, phase difference, and reflectance of the semi-transparent film 30 when the film thickness of the semi-transparent film 30 was changed.
FIG. 7 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Example 2, which was derived from the simulation results. As shown in the figure, the semi-transparent film 30 of Example 2 has a thickness in the range of 38 nm to 62 nm (Fig. It was found that the film thickness dependence of the transmittance for i-line (365 nm) was within an acceptable range (transmittance fluctuation within 2% when the film thickness changed 5 nm) over the range of Δd of 7. Furthermore, it was found that the film thickness dependence of the transmittance for the H-line (405 nm) was within an acceptable range (transmittance variation within 2% with a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>
Regarding the surface of the semi-transparent film 30 of the mask blank 10 of Example 2, the transmittance and phase difference at i-line (365 nm) were measured using MPM-100 manufactured by Lasertec. As a result, the transmittance of the semi-transparent film 30 for i-line (365 nm) in Example 2 was 44%, and the phase difference was 64 degrees.
In addition, when we measured the transmittance for i-line (365 nm) and h-line (405 nm) at 11 x 11 measurement points on the reference plane, the transmittance variation was within 1% for both. All were within acceptable ranges.
In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (ammonia permeate (APM), 30° C., 5 minutes) six times, and the change in transmittance due to changes in the thickness of the semi-permeable membrane 30 was evaluated. did. As a result, the variations in transmittance for i-line (365 nm) and h-line (405 nm) were both within 1%, which was within an acceptable range, compared to before the alkali cleaning treatment. Note that this evaluation was performed on a semi-transparent film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film forming conditions. From the above results, the semi-transparent film 30 of Example 2 is a semi-transparent film 30 that can suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light and has extremely small fluctuations in transmittance due to changes in film thickness. I can say that.

<Transfer mask 100 and its manufacturing method>
Using the mask blank 10 of Example 2 manufactured as described above, a transfer mask 100 was manufactured in the same manner as in Example 1, and a transfer pattern formation area was formed on a transparent substrate 20. A transfer mask 100 of Example 2 was obtained in which a semi-transparent film pattern 30a with a hole diameter of 1.5 μm and a light-shielding band made of a laminated structure of the semi-transparent film pattern 30a and the etching mask film pattern 40b were formed.

The transfer mask 100 of Example 2 obtained as described above can increase the transmittance for exposure light to enhance the transmittance adjustment effect, and has an in-plane distribution of transmittance for a plurality of wavelengths in the exposure light. Since the mask blank 10 is manufactured using the semi-transparent film 30 that can suppress the transmittance fluctuation due to the change in film thickness, the transmittance adjustment effect can be enhanced by increasing the transmittance for the exposure light. The transfer mask 100 has a semi-transparent film pattern 30a that can suppress the in-plane distribution of transmittance for a plurality of wavelengths of light and can also suppress changes in transmittance due to changes in film thickness.

From the above, when the transfer mask 100 of Example 2 is set on the mask stage of an exposure device and exposed and transferred to a resist film on a substrate for a display device, a transfer pattern including a fine pattern of less than 2.0 μm is obtained. It can be said that it is possible to transfer with high precision.

(Example 3)
The mask blank 10 of Example 3 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transparent film 30 was changed as described below.
The method for forming the semi-transparent film 30 of Example 3 is as follows.
In order to form the semi-transparent film 30 on the main surface of the transparent substrate 20, first, a mixed gas composed of argon (Ar) gas and nitrogen ( _N2 ) gas was introduced into the first chamber. Then, by reactive sputtering using a first sputter target containing molybdenum and silicon (molybdenum: silicon = 10.75:89.25), molybdenum, silicon, and nitrogen are added onto the main surface of the transparent substrate 20. A nitride of molybdenum silicide was deposited. The thickness of the semi-transparent film 30 was set to 59 nm so that the transmittance of the semi-transparent film 30 to the H-line (405 nm) was 46%. In this way, a semi-transparent film 30 made of molybdenum silicide nitride and having a thickness of 59 nm was formed.
Thereafter, in the same manner as in Example 1, an etching mask film 40 was formed.

Another semi-transparent film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film forming conditions as in Example 3 above. The refractive index n and extinction coefficient k of this semi-transparent film at i-line (365 nm), h-line (405 nm), and g-line (436 nm) were measured. The refractive index n at i-line (365 nm) was 2.37, and the extinction coefficient k was 0.34. Further, the refractive index n at the h-line (405 nm) was 2.38, and the extinction coefficient k was 0.30. The refractive index n at the g-line (436 nm) was 2.38, and the extinction coefficient k was 0.27.
As shown in FIG. 11, the semi-transparent film 30 of Example 3 has a refractive index n and an extinction coefficient k at the i-line (365 nm), and a refractive index n and extinction coefficient k at the h-line (405 nm). Both the refractive index n and the extinction coefficient k at the g-line (436 nm) were within the range defined by the above-mentioned (Formula 1) and (Formula 2).

Next, based on the refractive index n and extinction coefficient k of the semi-transparent film 30 of Example 3, the set film thickness is determined so that the transmittance of the semi-transparent film 30 to the h-line (405 nm) is 46%. , a simulation was conducted of the transmittance, phase difference, and reflectance of the semi-transparent film 30 when the film thickness of the semi-transparent film 30 was changed.
FIG. 8 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Example 3, which was derived from the simulation results. As shown in the figure, the semi-transparent film 30 of Example 3 has a thickness in the range of 47 nm to 67 nm (Fig. It was found that the film thickness dependence of the transmittance for the h-line (405 nm) was within an acceptable range (transmittance fluctuation within 2% when the film thickness changed 5 nm) over the range of Δd of 8). Furthermore, it was found that the film thickness dependence of the transmittance for i-line (365 nm) and g-line (436 nm) was within an acceptable range (transmittance variation within 2% with a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>
Regarding the surface of the semi-transparent film 30 of the mask blank 10 of Example 3, the transmittance and phase difference at the h-line (405 nm) were measured using MPM-100 manufactured by Lasertec. As a result, the transmittance of the semi-transparent film 30 at the h-line (405 nm) in Example 3 was 46%, and the phase difference was 67 degrees.
In addition, when we measured the transmittance for i-line (365 nm), h-line (405 nm), and g-line (436 nm) at 11 x 11 measurement points on the reference plane, we found that the transmittance fluctuation was was also within 1%, which was within an acceptable range.
In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (ammonia permeate (APM), 30° C., 5 minutes) six times, and the change in transmittance due to changes in the thickness of the semi-permeable membrane 30 was evaluated. did. As a result, the variations in transmittance for i-line (365 nm), h-line (405 nm), and g-line (436 nm) were all within 1%, which was within an acceptable range, compared to before the alkaline cleaning treatment. Note that this evaluation was performed on a semi-transparent film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film forming conditions. From the above results, the semi-transparent film 30 of Example 3 is a semi-transparent film 30 that can suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light and has extremely small fluctuations in transmittance due to changes in film thickness. I can say that.

<Transfer mask 100 and its manufacturing method>
Using the mask blank 10 of Example 3 manufactured as described above, a transfer mask 100 was manufactured in the same manner as in Example 1, and a transfer pattern formation area was formed on a transparent substrate 20. A transfer mask 100 of Example 3 was obtained in which a semi-transparent film pattern 30a with a hole diameter of 1.5 μm and a light-shielding band made of a laminated structure of the semi-transparent film pattern 30a and the etching mask film pattern 40b were formed.

The transfer mask 100 of Example 3 obtained as described above can suppress the in-plane distribution of the transmittance for a plurality of wavelengths of the exposure light even when the transmittance for the exposure light is increased. Since the mask blank 10 is manufactured using a semi-transparent film 30 that can suppress transmittance fluctuations due to film thickness fluctuations, the transmittance adjustment effect can be enhanced by increasing the transmittance of the exposure light, and it is possible to increase the transmittance adjustment effect by increasing the transmittance of the exposure light. The transfer mask 100 has a semi-transparent film pattern 30a that can suppress the in-plane distribution of transmittance for the transfer film, and can also suppress variations in transmittance due to variations in film thickness.

From the above, when the transfer mask 100 of Example 3 is set on the mask stage of an exposure device and exposed and transferred to a resist film on a substrate for a display device, a transfer pattern including a fine pattern of less than 2.0 μm is obtained. It can be said that it is possible to transfer with high precision.

(Comparative example 1)
The mask blank 10 of Comparative Example 1 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transparent film 30 was changed as described below.
The method for forming the semi-transparent film 30 of Comparative Example 1 is as follows.
In order to form the semi-transparent film 30 on the main surface of the transparent substrate 20, first, a mixed gas composed of argon (Ar) gas and nitrogen ( _N2 ) gas was introduced into the first chamber. Then, using a first sputter target containing molybdenum and silicon (molybdenum:silicon=20:80), molybdenum silicide containing molybdenum, silicon, and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. Nitride was deposited. The thickness of the semi-transparent film 30 was set to 5 nm so that the transmittance of the semi-transparent film 30 to the i-line (365 nm) was 46%. In this way, a semi-transparent film 30 made of molybdenum silicide nitride and having a thickness of 5 nm was formed.
Thereafter, in the same manner as in Example 1, an etching mask film 40 was formed.

Another semi-transparent film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film forming conditions as in Comparative Example 1 above. The refractive index n and extinction coefficient k of this semi-transparent film at i-line (365 nm), h-line (405 nm), and g-line (436 nm) were measured. The refractive index n at i-line (365 nm) was 3.50, and the extinction coefficient k was 1.81. Further, the refractive index n at the h-line (405 nm) was 3.60, and the extinction coefficient k was 1.61. The refractive index n at the g-line (436 nm) was 3.65, and the extinction coefficient k was 1.69.
The semi-transparent film 30 of Comparative Example 1 has a refractive index n and extinction coefficient k at the i-line (365 nm), a refractive index n and extinction coefficient k at the h-line (405 nm), and a refractive index n and extinction coefficient k at the g-line (436 nm). Both the refractive index n and extinction coefficient k of (not shown as it is outside the scope of the above).

Next, based on the refractive index n and extinction coefficient k of the semi-transparent film 30 of Comparative Example 1, the set film thickness is determined so that the transmittance of the semi-transparent film 30 for the i-line (365 nm) is 46%. , a simulation was conducted of the transmittance, phase difference, and reflectance of the semi-transparent film 30 when the film thickness of the semi-transparent film 30 was changed.
FIG. 9 is a diagram showing the relationship among the film thickness, transmittance, and reflectance of the semi-transparent film in Comparative Example 1, which was derived from the simulation results. As shown in the figure, the semi-transparent film 30 of Comparative Example 1 has a thickness in the range of 5 nm to 6 nm (Fig. 9), and the film thickness dependence of the transmittance for i-line (365 nm) is not within the permissible range (transmittance variation within 2% with a film thickness change of 5 nm). Understood. Furthermore, it was found that the film thickness dependence of the transmittance for H-line (405 nm) and G-line (436 nm) was not within the permissible range (transmittance variation within 2% with a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>
Regarding the surface of the semi-transparent film 30 of the mask blank 10 of Comparative Example 1, the transmittance and phase difference at i-line (365 nm) were measured using MPM-100 manufactured by Lasertec. As a result, the transmittance of the semi-transparent film 30 for i-line (365 nm) in Comparative Example 1 was 46%, and the phase difference was 12 degrees.
In addition, when we measured the transmittance for i-line (365 nm), h-line (405 nm), and g-line (436 nm) at 11 x 11 measurement points on the reference plane, we found that the transmittance fluctuation was Both of these values were well above 1%, which was outside the permissible range.
In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (ammonia permeate (APM), 30° C., 5 minutes) six times, and the change in transmittance due to changes in the thickness of the semi-permeable membrane 30 was evaluated. did. As a result, the changes in transmittance for i-line (365 nm), h-line (405 nm), and g-line (436 nm) compared to before the alkaline cleaning treatment all greatly exceeded 1%, which was outside the allowable range. Ta. Note that this evaluation was performed on a semi-transparent film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film forming conditions. From the above results, the semi-transparent film 30 of Comparative Example 1 cannot suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light, and the semi-transparent film 30 has large fluctuations in transmittance with respect to film thickness variations. I can say that there is.

<Transfer mask 100 and its manufacturing method>
Using the mask blank 10 of Comparative Example 1 manufactured as described above, a transfer mask 100 was manufactured in the same manner as in Example 1, and a transfer pattern formation area was formed on a transparent substrate 20. A transfer mask 100 of Comparative Example 1 was obtained in which a semi-transparent film pattern 30a with a hole diameter of 1.5 μm and a light-shielding band made of a laminated structure of the semi-transparent film pattern 30a and the etching mask film pattern 40b were formed.

The transfer mask 100 of Comparative Example 1 obtained as described above uses a mask blank 10 that has poor transmittance uniformity within the substrate surface and has large transmittance fluctuations with respect to film thickness fluctuations of the semi-transparent film 30. Therefore, when the transfer mask 100 is repeatedly cleaned, if the film thickness of the semi-transparent film pattern 30a decreases, the transmittance of the semi-transparent film pattern 30a will fluctuate greatly. , CD errors in pattern transfer due to the transfer mask 100 will occur.

(Comparative example 2)
The mask blank 10 of Comparative Example 2 was manufactured in the same manner as the mask blank 10 of Example 1, except that the semi-transparent film 30 was changed as described below.
The method for forming the semi-transparent film 30 of Comparative Example 2 is as follows.
In order to form the semi-transparent film 30 on the main surface of the transparent substrate 20, first, a mixed gas composed of argon (Ar) gas and nitrogen ( _N2 ) gas was introduced into the first chamber. Then, using a first sputtering target containing chromium and silicon (chromium:silicon=80:20), chromium silicide containing chromium, silicon, and nitrogen is deposited on the main surface of the transparent substrate 20 by reactive sputtering. Nitride was deposited. The thickness of the semi-transparent film 30 was set to 5 nm so that the transmittance of the semi-transparent film 30 to the i-line (365 nm) was 46%. In this way, a semi-transparent film 30 made of molybdenum silicide nitride and having a thickness of 5 nm was formed.
Thereafter, in the same manner as in Example 1, an etching mask film 40 was formed.

Another semi-transparent film was formed on the main surface of another synthetic quartz substrate (about 152 mm x about 152 mm) under the same film forming conditions as in Comparative Example 2 above. The refractive index n and extinction coefficient k of this semi-transparent film at i-line (365 nm), h-line (405 nm), and g-line (436 nm) were measured. The refractive index n at i-line (365 nm) was 2.45, and the extinction coefficient k was 2.81. Further, the refractive index n at the h-line (405 nm) was 2.55, and the extinction coefficient k was 3.00. The refractive index n at the g-line (436 nm) was 2.66, and the extinction coefficient k was 3.14.
The semi-transparent film 30 of Comparative Example 2 has a refractive index n and extinction coefficient k at the i-line (365 nm), a refractive index n and extinction coefficient k at the h-line (405 nm), and a refractive index n and extinction coefficient k at the g-line (436 nm). Both the refractive index n and extinction coefficient k of (not shown as it is outside the scope of the above).

Next, based on the refractive index n and extinction coefficient k of the semi-transparent film 30 of Comparative Example 2, the set film thickness is determined so that the transmissivity of the semi-transparent film 30 for the i-line (365 nm) is 46%. , a simulation was conducted of the transmittance, phase difference, and reflectance of the semi-transparent film 30 when the film thickness of the semi-transparent film 30 was changed.
FIG. 10 is a diagram showing the relationship between the film thickness, transmittance, and reflectance of the semi-transparent film in Comparative Example 2, which was derived from the simulation results. As shown in the figure, the semi-transparent film 30 of Comparative Example 2 has a thickness in the range of 4 nm to 5 nm (Fig. Transmittance fluctuation can only be tolerated within the range of Δd of 10), and the film thickness dependence of transmittance for i-line (365 nm) is not within the permissible range (transmittance fluctuation within 2% with a film thickness change of 5 nm). Understood. Furthermore, it was found that the film thickness dependence of the transmittance for H-line (405 nm) and G-line (436 nm) was not within the permissible range (transmittance variation within 2% with a film thickness change of 5 nm).

<Measurement of transmittance and phase difference>
Regarding the surface of the semi-transparent film 30 of the mask blank 10 of Comparative Example 2, the transmittance and phase difference at i-line (365 nm) were measured using MPM-100 manufactured by Lasertec. As a result, the transmittance of the semi-transparent film 30 for i-line (365 nm) in Comparative Example 1 was 46%, and the phase difference was 3 degrees.
In addition, when we measured the transmittance for i-line (365 nm), h-line (405 nm), and g-line (436 nm) at 11 x 11 measurement points on the reference plane, we found that the transmittance fluctuation was Both of these values were well above 1%, which was outside the permissible range.
In addition, the obtained semi-permeable membrane 30 was cleaned by repeating alkaline cleaning (ammonia permeate (APM), 30° C., 5 minutes) six times, and the change in transmittance due to changes in the thickness of the semi-permeable membrane 30 was evaluated. did. As a result, the changes in transmittance for i-line (365 nm), h-line (405 nm), and g-line (436 nm) compared to before the alkaline cleaning treatment all greatly exceeded 1%, which was outside the allowable range. Ta. Note that this evaluation was performed on a semi-transparent film 30 (dummy substrate) formed on a synthetic quartz glass substrate under the same film forming conditions. From the above results, the semi-transparent film 30 of Comparative Example 2 cannot suppress the in-plane distribution of transmittance for multiple wavelengths of exposure light, and the semi-transparent film 30 has a large variation in transmittance with respect to film thickness variations. I can say that there is.

<Transfer mask 100 and its manufacturing method>
Using the mask blank 10 of Comparative Example 2 manufactured as described above, a transfer mask 100 was manufactured in the same manner as in Example 1, and a transfer pattern formation area was formed on a transparent substrate 20. A transfer mask 100 of Comparative Example 2 was obtained in which a semi-transparent film pattern 30a with a hole diameter of 1.5 μm and a light-shielding band made of a laminated structure of the semi-transparent film pattern 30a and the etching mask film pattern 40b were formed.

The transfer mask 100 of Comparative Example 2 obtained as described above uses a mask blank 10 that has poor transmittance uniformity within the substrate surface and has large transmittance fluctuations with respect to film thickness fluctuations of the semi-transparent film 30. Therefore, when the transfer mask 100 is repeatedly cleaned, if the film thickness of the semi-transparent film pattern 30a decreases, the transmittance of the semi-transparent film pattern 30a will fluctuate greatly. , CD errors in pattern transfer due to the transfer mask 100 will occur.

In the above embodiments, examples of the transfer mask 100 for manufacturing a display device and the mask blank 10 for manufacturing the transfer mask 100 for manufacturing a display device have been described, but the present invention is not limited thereto. The mask blank 10 and/or the transfer mask 100 of the present invention can also be applied to semiconductor device manufacturing, MEMS manufacturing, printed circuit board manufacturing, and the like.

Further, in the above embodiment, the size of the transparent substrate 20 is 1214 size (1220 mm x 1400 mm x 13 mm), but the size is not limited to this. In the case of the mask blank 10 for manufacturing display devices, a large-sized transparent substrate 20 is used, and the size of the transparent substrate 20 is such that the length of one side of the main surface is 300 mm or more. The size of the transparent substrate 20 used in the mask blank 10 for manufacturing a display device is, for example, 330 mm x 450 mm or more and 2280 mm x 3130 mm or less.

Further, in the case of the mask blank 10 for semiconductor device manufacturing, MEMS manufacturing, and printed circuit board manufacturing, a small size light-transmitting substrate 20 is used, and the size of the light-transmitting substrate 20 is determined by the length of one side. The length is 9 inches or less. The size of the transparent substrate 20 used in the mask blank 10 for the above application is, for example, 63.1 mm x 63.1 mm or more and 228.6 mm x 228.6 mm or less. Usually, a 6025 size (152 mm x 152 mm) or a 5009 size (126.6 mm x 126.6 mm) is used as the light-transmitting substrate 20 for the transfer mask 100 for semiconductor device manufacturing and MEMS manufacturing. Furthermore, 7012 size (177.4 mm x 177.4 mm) or 9012 size (228.6 mm x 228.6 mm) is usually used as the light-transmitting substrate 20 for the transfer mask 100 for manufacturing printed circuit boards. Ru.

10 Mask blank 20 Transparent substrate 30 Semi-transparent film 30a Semi-transparent film pattern (transfer pattern)
40 Etching mask film 40a First etching mask film pattern (transfer pattern)
40b Second etching mask film pattern 50 First resist film pattern 60 Second resist film pattern 100 Transfer mask

Claims (16)

A mask blank comprising a transparent substrate and a semi-transparent film provided on a main surface of the transparent substrate,
a refractive index n and an extinction coefficient k for light with a wavelength of 365 nm in the semi-transparent film;
A mask blank characterized in that a refractive index n and an extinction coefficient k for light having a wavelength of 405 nm both satisfy the relationships of (Formula 1) and (Formula 2).
(Formula 1) k≧0.282×n−0.514
(Formula 2) k≦0.500×n+0.800 2. The mask blank according to claim 1, wherein an extinction coefficient k of the semi-transparent film for light having a wavelength of 365 nm is larger than zero. 2. The mask blank according to claim 1, wherein the semi-transparent film has a refractive index n of 2.0 or more for light having a wavelength of 365 nm. The mask blank according to claim 1, wherein the thickness of the semi-transparent film is 30 nm or more and 70 nm or less. 2. The mask blank according to claim 1, wherein the semi-transparent film has a transmittance of 20% or more and 70% or less for light having a wavelength of 365 nm. 2. The mask blank according to claim 1, wherein the semi-transparent film has a phase difference of 0 degrees or more and 120 degrees or less with respect to light having a wavelength of 365 nm. 2. The mask blank according to claim 1, wherein the refractive index n and extinction coefficient k for light with a wavelength of 436 nm in the semi-transparent film also satisfy the relationships of (Equation 1) and (Equation 2). The mask blank according to claim 1, wherein the semi-transparent film contains metal, silicon, and nitrogen. 2. The mask blank according to claim 1, further comprising an etching mask film having etching selectivity different from that of the semi-transparent film on the semi-transparent film. 10. The mask blank according to claim 9, wherein the etching mask film contains chromium. A transfer mask, wherein a transfer pattern is formed on the semi-transparent film of the mask blank according to claim 1. 10. A transfer mask according to claim 9, wherein a transfer pattern is formed on the semi-transparent film of the mask blank, and a pattern different from the transfer pattern is formed on the etching mask film. preparing a mask blank according to claim 1;
forming a resist film having a transfer pattern on the semi-transparent film;
performing wet etching using the resist film as a mask to form a transfer pattern on the semi-transparent film;
A method for manufacturing a transfer mask, comprising: preparing a mask blank according to claim 9;
forming a resist film having a transfer pattern on the etching mask film;
performing wet etching using the resist film as a mask to form a transfer pattern on the etching mask film;
performing wet etching using an etching mask film on which the transfer pattern is formed as a mask to form a transfer pattern on the semi-transparent film;
A method for manufacturing a transfer mask, comprising: placing the transfer mask according to claim 11 or 12 on a mask stage of an exposure device;
irradiating the transfer mask with exposure light to transfer the transfer pattern to a photosensitive film provided on a substrate for a display device;
A method for manufacturing a display device, comprising: 16. The method of manufacturing a display device according to claim 15, wherein the exposure light is composite light including light with a wavelength of 365 nm and light with a wavelength of 405 nm.

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