TW201945832A - Large-size photomask - Google Patents

Abstract

Provided is a large-size photomask characterized by comprising a translucent substrate and a light-shielding pattern arranged on a surface of the translucent substrate, wherein the light-shielding pattern has a layered structure in which a first low reflection film, a light shielding film, and a second low reflection film are layered in this order from the translucent substrate side, and a reflection rate to light in a wavelength region of 313 nm to 436 nm of the translucent substrate side surface of the light-shielding pattern is 8% or less.

Description

Large photomask

The present invention relates to a large-sized photomask used for manufacturing display device functional elements and the like.

In the field of flat-panel displays such as liquid crystal display devices and organic EL (Electro-Luminescence) display devices, in recent years, people have expected higher-definition displays and are moving towards higher pixelation. In addition, along with this, functional elements for display devices such as TFT (Thin Film Transistor) substrates and color filters are required to be finely processed.

As a microfabrication method when manufacturing a functional element for a display device, a photolithography method using a photomask is preferably used from the past. As the photomask, a photomask having a light-shielding pattern provided on a surface of a light-transmitting substrate and having a light-transmitting region and a light-shielding region is generally used.

When such a photomask is used in an exposure device and a pattern is transferred to a transferee, when the photomask has a high reflectance to the exposed light, the stray light caused by the light reflected by the exposure is reflected on the photomask. This affects the accuracy of transferring the pattern to the object to be transferred. In order to suppress such a problem, a technique of reducing the reflectivity of the photomask to the exposed light is used. As such a technique, for example, Patent Document 1 and the like describe a configuration of a photomask provided with an anti-reflection film on the surface side of a light-shielding pattern.

On the other hand, the manufacturing technology of flat panel displays has been improving year by year with the increase of the resolution of high definition. Following this, panel makers are also developing technologies for forming finer patterns with high accuracy. However, in recent years, in the field of exposure technology for transferring patterns to a transferee, in order to form finer patterns with high accuracy, The tendency to use high-sensitivity resists. FIG. 11 is a graph comparing a change in transfer line width shift with respect to an exposure amount using an existing low-sensitivity resist and a high-sensitivity resist used in recent years. As shown in FIG. 11, compared with a low-sensitivity resist, a high-sensitivity resist requires less exposure amount for hardening, and the variation of the transfer line width shift in the stage with less exposure amount is larger.

Therefore, with the tendency to use high-sensitivity resists, the following problems have arisen: The weak stray light that can be ignored previously has an effect on the resist layer during exposure, which leads to the occurrence of instability in the pattern transferred to the transferee. Uniform or dimensional deviation.

Furthermore, in recent years, when a large-area pattern is formed with high accuracy, the exposure light including the g-line, the h-line, or the i-line has insufficient energy of the exposure light irradiated to the resist layer, and therefore is required to be used. The exposure light including light of a plurality of wavelengths such as g-line, h-line, and i-line is particularly required to use exposure light including j-line having a larger energy among these lights. On the other hand, in the case of using such exposed light, the change in the resist layer at the time of photosensitivity becomes larger, so the influence of the above-mentioned weak stray light on the resist layer is further increased, so the above-mentioned problem becomes obvious.

In contrast, the structure described in Patent Document 1 and the like can sufficiently reduce the intensity of stray light generated by reflection of the exposed light on the mask during exposure, so that transfer to the object to be transferred can be suppressed. Unevenness or dimensional deviation appears in the above pattern.

[Prior technical literature]
[Patent Literature]

[Patent Document 1] Patent Publication No. 4451391

[Problems to be solved by the invention]

The present invention has been made in view of the above-mentioned problems, and a main object thereof is to provide a large-scale photomask capable of suppressing occurrence of unevenness or dimensional deviation in a pattern transferred to a transfer target.
[Technical means to solve the problem]

In order to solve the above problems, the present invention provides a large photomask, which is characterized in that it is a large photomask including a light-transmitting substrate and a light-shielding pattern provided on the surface of the light-transmitting substrate. A reflective film, a light-shielding film, and a second low-reflection film are laminated in this order from the light-transmitting substrate side, and the light-shielding pattern has a wavelength of 313 nm to 436 nm on the light-transmitting substrate side. The light reflectance of the area is 8% or less.

According to the present invention, it is possible to suppress occurrence of unevenness or dimensional deviation in a pattern transferred to a transfer target.

In the above invention, it is preferable that a reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-shielding pattern on the side opposite to the light-transmitting substrate is 10% or less.

Moreover, in the said invention, it is preferable that the said light-shielding film contains chromium, and the said 1st low reflection film and said 2nd low reflection film contain chromium oxide.

In the above invention, the optical density (OD) of the light-shielding pattern with respect to light in a wavelength region of 313 nm to 436 nm is preferably 4.5 or more.

Moreover, in the said invention, it is preferable that the inclination angle of the side surface of the said light-shielding film with respect to the said transparent substrate is 80 degrees or more and 90 degrees or less. This is because the influence of reflected light of the exposed light irradiated to the side surface of the light-shielding film can be suppressed.

Moreover, in the said invention, it is preferable that the side surface of the said 1st low reflection film or the side surface of the said 2nd low reflection film protrudes in the direction parallel to the surface of the said translucent substrate with respect to the side surface of the said light-shielding film.

It is particularly preferable that both of the side surface of the first low-reflection film and the side surface of the second low-reflection film protrude in a direction parallel to the surface of the transparent substrate with respect to the side surface of the light-shielding film, and further, the first The side surface of the 1 low reflection film is more protruded in a direction parallel to the surface of the transparent substrate than the side surface of the second low reflection film.

Preferably, at least the side surface of the first low-reflection film projects from the side surface of the light-shielding film in a direction parallel to the surface of the light-transmitting substrate, and the side surface of the first low-reflection film is preferably opposite to the surface. The angle of the surface of the translucent substrate is 56 ° or less. The reason is that it is easy to remove foreign matter by washing, and the amount of foreign matter present can be reduced.

Moreover, in the said invention, it is preferable that the side surface of the said light-shielding film is concave shape.

Further, in the above invention, it is preferable to have a division pattern for division exposure, and the division pattern is the light-shielding pattern.
[Effect of the invention]

In the present invention, the effect of suppressing occurrence of unevenness or dimensional deviation in a pattern transferred to a transfer target is exhibited.

Hereinafter, the large photomask of the present invention will be described in detail.

The large photomask of the present invention is characterized in that it is a large photomask including a light-transmitting substrate and a light-shielding pattern provided on a surface of the light-transmitting substrate. The light-shielding pattern includes a first low-reflection film, a light-shielding film, and The second low-reflection film is a laminated structure formed by laminating the light-transmitting substrate in this order, and the reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-transmitting substrate side of the light-shielding pattern is 8% or less.

An example of the large photomask of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of a large-sized photomask of the present invention. In addition, FIG. 2 is a schematic cross-sectional view showing a step of transferring a pattern to a resist layer included in a transfer target body by using the large-scale photomask shown in FIG. 1 by exposure.

As shown in FIG. 1, the large-sized photomask 100 includes a light-transmitting substrate 110 and a light-shielding pattern 120 provided on a surface 110 a of the light-transmitting substrate 110. The light-shielding pattern 120 has a laminated structure in which the first low-reflection film 122, the light-shielding film 124, and the second low-reflection film 126 are laminated in this order from the transparent substrate 110 side. For any light in the wavelength range from 313 nm to 436 nm, the reflectance of the surface 120a on the light-transmitting substrate 110 side of the light-shielding pattern 120 is 8% or less.

Therefore, as shown in FIG. 2, the pattern is transferred to the substrate by using a large-scale reticle 100 to expose a light source (UV (Ultra Violet, Ultraviolet) lamp) by radiating light including an exposure light of any light in the above-mentioned wavelength region. In the case of the transferred body 200 having the resist layer 220 formed on 210, the surface 120a of the light-transmitting substrate 110 side of the light-shielding pattern 120 and the surface 300a of the exposure shielding plate 300 may be reduced by the exposure light described above. The intensity of the stray light generated by multiple reflections of alternate reflections between the optical substrate 110 and the interface 112 of the air (not shown) can be used to irradiate the shielded area originally shielded by the exposure shield 300 with the exposure light The intensity of the stray light La on the resist layer 220 is reduced to, for example, less than 0.3% of the exposure illuminance. Thereby, unevenness or dimensional deviation in the pattern on the resist layer 220 transferred to the shielded area can be suppressed.

Therefore, according to the present invention, the intensity of stray light generated by the reflection of the exposed light on the surface of the light-transmitting substrate side of the light-shielding pattern when exposure is performed using light including any light in the above-mentioned wavelength region is performed. , Can suppress unevenness or dimensional deviation in the pattern transferred to the transferred body.

In recent years, when manufacturing a large-area pattern with high accuracy in the manufacture of a flat panel display, it is necessary to include a g-line (wavelength 436 nm), an h-line (wavelength 405 nm), or an i-line (wavelength 365 nm). The energy of the exposed light may be insufficient. Therefore, it is required to use exposure light including a plurality of wavelengths of light such as g-line, h-line, and i-line, and in particular, it is required to use exposure light including a j-line (wavelength 313 nm) having a larger energy among these lights.

On the other hand, the change in the resist layer when exposed to light with exposure light containing a plurality of wavelengths of light is greater than the exposure to light with a single wavelength, especially when exposed to light with j-rays. The change of the resist layer becomes larger as time passes. Therefore, in the case of using exposure light including light having a plurality of wavelengths, especially exposure light including j-rays, the effect of weak stray light on the resist is further increased, so transfer to the object to be transferred The problem of unevenness in the pattern becomes apparent. In contrast, in the large-scale reticle 100 shown in FIG. 1, the reflectance is 8% or less for any light in the above-mentioned wavelength region. Therefore, for any of the g-line, h-line, i-line, and j-line, Both can reduce the reflectance of the surface 120a on the light-transmitting substrate 110 side of the light-shielding pattern 120 to 8% or less.

Therefore, according to the present invention, when exposure light using a plurality of wavelengths of light including g-line, h-line, i-line, etc., especially exposure light including j-line is used for exposure, the transfer to the transferred light can be significantly suppressed. Unevenness in the pattern on the print.

1. Light-shielding pattern The light-shielding pattern is provided on the surface of the light-transmitting substrate, and includes the first low-reflection film, the light-shielding film, and the second low-reflection film, which are laminated in this order from the light-transmitting substrate side. In the formed multilayer structure, the reflectance of light in a wavelength region of 313 nm to 436 nm on the light-transmitting substrate side of the light-shielding pattern is 8% or less.

(1) Reflectance of light in a wavelength range of 313 nm to 436 nm The reflectance of light in a wavelength range of 313 nm to 436 nm on the light-transmitting substrate side of the light-shielding pattern is 8% or less. That is, for any light in the wavelength region, the reflectance of the light-shielding pattern on the surface of the light-transmitting substrate side is 8% or less.

The surface of the light-transmitting substrate side serving as the light-shielding pattern is not particularly limited as long as the reflectance of light in the above-mentioned wavelength region is 8% or less, but among them, the light in the wavelength region of 365 nm to 436 nm is preferred. The reflectance is 5% or less. When exposure is performed using exposure light including any light in a wavelength range of 365 nm to 436 nm, the intensity of the stray light La shown in FIG. 2 can be reduced to, for example, less than 0.2% of the exposure illuminance. The reason is that the intensity of the above-mentioned stray light can be reduced from the level of the boundary of the photosensitive layer's resist layer to the level at which it has no effect at all. Furthermore, it is particularly preferable that the reflectance of light in a wavelength range of 313 nm to 365 nm is 5% or less. The reason is that the same effect can be obtained when exposure is performed using exposure light including light in a wider range of wavelength regions. More specifically, the reason lies in not only current exposure devices and resists that use light exposed in a wavelength range of 365 nm to 436 nm, but also other exposure devices that use light exposed in a wavelength range of 313 nm to 365 nm. And resist can also achieve the same effect.

Among them, in the present invention, as the method for measuring the reflectance on the light-transmitting substrate side surface of the light-shielding pattern, a device using a photodiode array as a detector (Multichannel Photo Detector Otsuka Electronics MCPD) , Multi-channel spectrometer)).

It is preferable that the reflectance of the light in the wavelength region of 313 nm to 436 nm on the opposite side of the light-shielding pattern to the translucent substrate is 10% or less. That is, it is preferable that the reflectance of the light-shielding pattern on the opposite side of the light-transmitting substrate to any light in the wavelength region is 10% or less.

The method for measuring the reflectance of the light-shielding pattern on the surface opposite to the light-transmitting substrate is the same as the method of measuring the reflectance on the light-transmitting substrate-side surface of the light-shielding pattern.

In the large photomask 100 shown in FIG. 1, for any light in a wavelength range of 313 nm to 436 nm, the reflectance of the surface 120 b of the light-shielding pattern 120 on the opposite side of the transparent substrate 110 is 10% or less. Therefore, as shown in FIG. 2, a pattern is transferred to a substrate 210 having a resist layer 220 formed thereon by using a large photomask 100 and exposing using exposure light including any light in the above-mentioned wavelength region. In the case of the printed body 200, the interface 212 or the resist layer of the air (not shown) and the resist layer 220 on the surface 120b on the side opposite to the light-transmitting substrate 110 of the light-shielding pattern 120 due to the above exposure is reduced. The intensity of the stray light generated by multiple reflections such as alternate reflections between the interface 214 of the substrate 220 and the substrate 210 can irradiate the original stray light on the resist layer 220 which is irradiated by the edge portion of the light-shielding pattern 120 to block the exposed light. The intensity of the astigmatism Lb is reduced to, for example, less than 2.0% of the exposure illuminance. Thereby, the occurrence of dimensional deviation and the like in the pattern on the resist layer 220 transferred to the edge portion can be suppressed.

Therefore, it is preferable that the reflectance of light in the above-mentioned wavelength region is 10% or less. The reason is that, when the exposure light using any light including the above-mentioned wavelength range is used for exposure, the intensity of stray light generated by reflection of the exposed light on the surface of the light-shielding pattern opposite to the transparent substrate is reduced. , Can effectively suppress the occurrence of dimensional deviation in the pattern transferred to the transferred body. The reason for this is that when exposure light using a plurality of wavelengths of light including the g-line, h-line, and i-line is used, especially when exposure light including the j-line is used for exposure, the transfer to the transfer can be more significantly suppressed. There are dimensional deviations in the pattern on the body.

The surface of the light-shielding pattern opposite to the light-transmitting substrate preferably has a reflectance of 10% or less for light in the above-mentioned wavelength region, but is particularly preferably for the wavelength region of 365 to 436 nm. The reflectance of light is 5% or less. When exposure is performed using exposure light including any light in a wavelength range of 365 nm to 436 nm, the intensity of the stray light Lb shown in FIG. 2 can be reduced to, for example, less than 1.0% of the exposure illuminance. The reason for this is that the intensity of the stray light can be transferred from the resist layer to such an extent that the pattern on the resist layer of the transferred body in the edge portion of the light-shielding pattern is transferred with a dimensional deviation. The level of the boundary of the light is reduced to a level where the above-mentioned dimensional deviations and the like do not occur at all. Furthermore, it is particularly preferable that the reflectance of light in a wavelength range of 313 nm to 365 nm is 5% or less. The reason is that the same effect can be obtained when exposure is performed using exposure light including light in a wider range of wavelength regions. More specifically, the reason lies in not only current exposure devices and resists that use light exposed in a wavelength range of 365 nm to 436 nm, but also other exposure devices that use light exposed in a wavelength range of 313 nm to 365 nm. And resist can also achieve the same effect.

(2) The first low-reflection film The first low-reflection film is provided on the light-transmitting substrate side in the laminated structure of the light-shielding pattern, which realizes that the surface of the light-transmitting substrate side of the light-shielding pattern faces 313 nm Functional film that reduces the reflectance of light in the wavelength range of ~ 436 nm to less than 8%.

When the light-shielding pattern has the first low-reflection film, and when light in the wavelength region is irradiated to the surface of the light-transmitting substrate side of the light-shielding pattern, the light-transmitting property of the first low-reflection film is The light reflected from the substrate-side surface, the light reflected at the interface inside the first low-reflection film, and the light reflected from the interface between the first low-reflection film and the light-shielding film are mutually weakened by interference. Thereby, the reflectance of the surface of the light-transmitting substrate side of the light-shielding pattern with respect to the light in the wavelength region can be reduced to 8% or less.

As described above, when using exposure light including a plurality of wavelengths of light such as g-line, h-line, and i-line, especially exposure light including j-line, the influence of weak stray light on the resist further changes. Large, so that the problem of unevenness in the pattern transferred to the object to be transferred becomes obvious. On the other hand, it is difficult to form a film to solve such a problem, and the film achieves a function of reducing the reflectance of light facing the wavelength region to the light-transmitting substrate side of the light-shielding pattern to 8% or less. In the present invention, in spite of such a situation, a film capable of reducing the reflectance of light facing the wavelength region on the translucent substrate side to 8% or less can be formed.

a. The first low-reflection film is used as the film thickness of the first low-reflection film, as long as the function of reducing the reflectance of light facing the wavelength region to the light-transmitting substrate side of the light-shielding pattern to 8% or less Although it does not specifically limit, It is preferable that the film thickness is in the range of 10 nm to 50 nm. The reason is that if the thickness is too thin, the function of reducing the reflectance is reduced, and if it is too thick, it is difficult to process the light-shielding pattern with high accuracy.

The material of the first low-reflection film is not particularly limited as long as it can reduce the reflectance of light facing the wavelength region to 8% or less on the light-transmitting substrate side of the light-shielding pattern. For example, it may be Examples of chromium oxide (CrOx), chromium oxynitride (CrON), chromium nitride (CrN), titanium oxide (TiO), titanium oxynitride (TiON), tantalum oxide (TaO), tantalum silicon oxide (TaSiO), nickel oxide Aluminum (NiAlO), molybdenum silicon oxide (MoSiO), and molybdenum silicon nitride oxide (MoSiON). Among them, chromium oxide (CrOx) and chromium oxynitride (CrON) are preferred, and chromium oxide (CrOx) is particularly preferred.

b. Formation method As the formation method of the first low-reflection film, for example, a sputtering method, a vacuum evaporation method, an ion plating method, and the like can be mentioned. More specifically, for example, a method of mounting a Cr target in a vacuum chamber, introducing O ₂ , N ₂ , and CO ₂ gas, and forming a film by reactive sputtering in a vacuum environment can be cited.
Furthermore, in this method, the light-transmitting substrate side of the light-shielding pattern is increased by increasing the ratio of O ₂ gas compared to the case where a low-reflection film in a light-shielding pattern of an ordinary binary photomask is formed. The reflectance of light in the wavelength range of 313 nm to 436 nm is reduced to less than 8%.

(3) The second low-reflection film The second low-reflection film is provided on the opposite side of the light-transmitting substrate in the laminated structure of the light-shielding pattern, and it is a surface that is opposite to the light-transmitting substrate to reduce the light-shielding pattern Functional film that reflects light in the wavelength range of 313 nm to 436 nm.

When the light-shielding pattern has the second low-reflection film, when light in the wavelength region is incident on a surface of the light-shielding pattern on the side opposite to the translucent substrate, The light reflected from the surface on the opposite side of the light-transmitting substrate, the light reflected from the internal interface of the second low-reflection film, and the light reflected from the boundary between the second low-reflection film and the light-shielding film are weakened by interference. Thereby, the reflectance of the light of the light-shielding pattern on the side opposite to the transparent substrate facing the wavelength region can be reduced.

a. The second low-reflection film serves as the second low-reflection film, as long as the function of reducing the reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-shielding pattern on the side opposite to the transparent substrate is achieved. The film is not particularly limited, but is preferably a film that achieves the function of reducing the reflectance of light on the opposite side facing the wavelength region of 313 nm to 436 nm to 10% or less.

As described above, when using exposure light including a plurality of wavelengths of light such as g-line, h-line, and i-line, especially exposure light including j-line, the influence of weak stray light on the resist is further increased. As the size becomes larger, problems such as dimensional deviation appearing in the pattern transferred to the object to be transferred become obvious. On the other hand, it is difficult to form an anti-reflection film to effectively solve this problem. The anti-reflection film realizes a reduction in the reflectance of the light of the light-shielding pattern on the side opposite to the light-transmitting substrate facing the wavelength region to 10. Functions below%. In the present invention, although this is the case, a film capable of reducing the reflectance of the light facing the above-mentioned wavelength region on the opposite side to less than 10% can be formed.

The film thickness of the second low-reflection film is not particularly limited as long as it can achieve the function of reducing the reflectance of light in the wavelength region facing the light-shielding pattern on the side opposite to the transparent substrate, but it is preferably a film. The thickness is in the range of 10 nm to 50 nm. The reason is that if the thickness is too thin, the function of reducing the reflectance is reduced, and if it is too thick, it is difficult to process the light-shielding pattern with high accuracy.

The material of the second low-reflection film is the same as that of the first low-reflection film, so the description is omitted here.

b. Forming method The forming method of the second low-reflection film is to reduce the reflectance of light in a wavelength range of 313 nm to 436 nm on the opposite side of the light-shielding pattern from the transparent substrate to 10% or less. Since it is the same as the method of forming the first low-reflection film, the description is omitted here.

(4) Light-shielding film The light-shielding film is a light-shielding film provided between the first low-reflection film and the second low-reflection film in the multilayer structure of the light-shielding pattern.

a. The light-shielding film is not particularly limited as a film thickness of the light-shielding film, but the film thickness is preferably in a range of 80 nm to 180 nm. The reason is that if it is too thin, it is difficult to obtain the required light-shielding property, and if it is too thick, it is difficult to process the light-shielding pattern with high accuracy.

The material of the light-shielding film is not particularly limited as long as it is a material having light-shielding properties. Examples include chromium (Cr), chromium oxynitride (CrON), chromium nitride (CrN), and molybdenum silicon oxide (MoSiO). , Molybdenum silicon oxynitride (MoSiON), tantalum oxide (TaO) and tantalum silicon oxide (TaSiO). Among these, chromium (Cr) is preferred.

b. Method for forming a light-shielding film As the method for forming the light-shielding film, for example, a sputtering method, a vacuum evaporation method, an ion plating method, and the like can be cited.

In addition, as a method for forming the light-shielding film in which the optical density (OD) of the light-shielding pattern with respect to light in the wavelength region is 4.5 or more, for example, a method of increasing the film-forming time of the light-shielding film or increasing The method of the number of film formation scans.

(5) Shading pattern
a. Optical density (OD)
As the light-shielding pattern, the optical density (OD) of light in a wavelength region of 313 nm to 436 nm is preferably 4.5 or more. That is, it is preferable that the optical density (OD) of any light in the above-mentioned wavelength region is 4.5 or more.

Among them, in the present invention, an ultraviolet / visible spectrophotometer (Hitachi U-4000) can be used in the method for measuring the optical density (OD) of light in the above-mentioned wavelength region.

In the large photomask 100 shown in FIG. 1, the optical density (OD) of the light-shielding pattern 120 with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. That is, the optical density (OD) of the light-shielding pattern 120 with respect to any light in the wavelength region is 4.5 or more. Therefore, as shown in FIG. 2, a pattern is transferred to a substrate 210 having a resist layer 220 formed thereon by using a large photomask 100 and exposing using exposure light including any light in the above-mentioned wavelength region. In the case of the printed body 200, the intensity of the transmitted light Lc transmitted through the light-shielding pattern 120 as described above can be reduced to, for example, 0.001% or less of the exposure illuminance. Thereby, unevenness in the pattern transferred to the resist layer 220 can be suppressed.

Therefore, the optical density (OD) is preferably 4.5 or more. The reason is that when exposure light using any light including the above-mentioned wavelength region is used for exposure, by reducing the intensity of the light transmitted through the light-shielding pattern through the exposure light, the pattern transferred to the object to be transferred can be effectively suppressed. Inequalities appear. The reason is that the exposure to light with a plurality of wavelengths including g-line, h-line, and i-line, especially the exposure light including j-line, can effectively suppress the transfer to the transferee. Unevenness appears in the pattern.

Furthermore, in general, it is not appropriate to increase the optical density (OD) of the light-shielding pattern in the photomask in view of the fact that the light-shielding pattern becomes thick and it is difficult to perform high-precision processing. This tendency is particularly noticeable in photomasks used in the manufacture of semiconductor integrated circuits.

b. size
(a) Width The width of the light-shielding pattern includes, for example, a width of 0.1 μm or more and less than 10.0 μm. The width of the light-shielding pattern is preferably a width after the size is controlled at the sub-micron level.

The width of the light-shielding pattern is defined by a dimension of a short-side direction of a plan view shape. In addition, the width after the size is controlled at the sub-micron level refers to the width after the size is controlled in units of 0.1 μm, for example, a width of 0.1 μm or more and less than 1.0 μm.

(b) The film thickness is not particularly limited as the overall film thickness of the light-shielding pattern, but is preferably within a range of 100 nm to 250 nm. The reason is that if it is too thin, it is difficult to obtain the required light-shielding property, and if it is too thick, it is difficult to process the light-shielding pattern with high accuracy.

c. Cross-sectional shape As the light-shielding pattern, it is preferable that the optical density (OD) of the light in the above-mentioned wavelength region is 4.5 or more, and it has a desired cross-sectional shape. Hereinafter, a preferable cross-sectional shape of the light-shielding pattern will be described.

FIG. 3 is an enlarged view showing the area within the dotted frame shown in FIG. 1 upside down. As shown in FIG. 3, in the large-scale photomask 100 shown in FIG. 1, the optical density (OD) of the light-shielding pattern 120 with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. In the opening portion 120c of the light-shielding pattern 120, the inclination angle α of the side surface 124a of the light-shielding film 124 with respect to the light-transmitting substrate 110 is 80 degrees or more and 90 degrees or less. On the other hand, FIG. 4 is a schematic cross-sectional view showing a region corresponding to FIG. 3 in a large-sized photomask of the prior art. As shown in FIG. 4, in the large-scale photomask 100 of the prior art, the inclination angle α of the side surface 124 a of the light-shielding film 124 with respect to the light-transmitting substrate 110 does not reach 80 degrees.

As shown in FIG. 3, when the inclination angle α of the side surface 124 a of the light-shielding film 124 with respect to the light-transmitting substrate 110 is 80 degrees or more and 90 degrees or less, the inclination angle α as shown in FIG. 4 is less than 80 degrees. In a different situation, when the pattern is transferred to the exposure of the resist layer of the transferee, the reflected light (stray light) of the exposed light (stray light) irradiated from the oblique direction of the light source side to the side 124a of the light-shielding film 124 is The possibility of being induced to the opening 120c side of the light-shielding pattern 120 increases. Accordingly, it is possible to suppress the reflected light from being irradiated on the resist layer that blocks the exposure of the exposed light by the edge portion of the light-shielding pattern 120. Thereby, the occurrence of dimensional deviation and the like in the pattern on the resist layer transferred to the edge portion can be suppressed.

Therefore, as the light-shielding pattern with an optical density (OD) of 4.5 or more with respect to the light in the wavelength region, as shown in FIG. 3, it is preferable that the inclination angle of the side surface of the light-shielding film with respect to the light-transmitting substrate is Above 80 degrees and below 90 degrees. The reason is that since the optical density (OD) is 4.5 or more and the light-shielding pattern is a thick film, the amount of light reflected by the light exposed from the oblique direction of the light source side to the side of the light-shielding film is increased. However, by the influence of the reflected light, it is possible to suppress the occurrence of dimensional deviation and the like in the pattern transferred to the object to be transferred.

In addition, the inclination angle of the side surface of the light-shielding film with respect to the light-transmitting substrate refers to the angle of inclination of the wiring on the edge of the light-transmitting substrate side of the side of the light-shielding film indicated by α in FIG. 3. .

5 to 7 are schematic cross-sectional views respectively showing a region corresponding to FIG. 3 in another example of the large-sized photomask of the present invention.

In the large photomask 100 shown in FIG. 5, the optical density (OD) of the light-shielding pattern 120 with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. In the opening 120c of the light-shielding pattern 120, the side surface 124a of the light-shielding film 124 is a plane perpendicular to the light-transmitting substrate 110, and the side surface 122a of the first low-reflection film 122 and the side surface 126a of the second low-reflection film 126 are light-shielded. The side surface 124 a of the transparent film 124 protrudes only by a length L1 in a direction parallel to the translucent substrate 110.

In the large-scale mask 100 shown in FIG. 6, the optical density (OD) of the light-shielding pattern 120 with respect to light in a wavelength range of 313 nm to 436 nm is 4.5 or more. In the opening 120c of the light-shielding pattern 120, the side surface 124a of the light-shielding film 124 is a concave surface including a plurality of planes, and the side surface 122a of the first low-reflection film 122 and the side surface 126a of the second low-reflection film 126 are light-shielding. The side surface 124a of the film 124 protrudes in a direction parallel to the light-transmitting substrate 110, and protrudes from the position of the side surface 124a of the light-shielding film 124 farthest from the opening 120c by a length L2. The side surface 124 a of the light-shielding film 124 is recessed in the width W1 from a position closest to the opening 120 c to a position farthest from the opening 120 c in a direction parallel to the light-transmitting substrate 110.

Furthermore, in the large-scale photomask 100 shown in FIG. 7, the optical density (OD) of the light-shielding pattern 120 with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. In the opening 120c of the light-shielding pattern 120, the side surface 124a of the light-shielding film 124 is a concave curved surface. The side surface 124a of the light-shielding film 124 is recessed in the width W2 from the position closest to the opening 120c to the position farthest from the opening 120c.

In the large photomask 100 shown in FIGS. 5 and 6, the side surface 122 a of the first low-reflection film 122 and the side surface 126 a of the second low-reflection film 126 are opposite to the side surface 124 a of the light-shielding film 124 on the light-transmitting substrate 110. The surface 110a projects in a parallel direction. Therefore, when the pattern is transferred to the exposure of the resist layer of the transferee, the exposure light (stray light) from the oblique direction of the light source side to the side surface 124a of the light-shielding film 124 decreases from the first level. The reflection film 122 is weakened and irradiated to the side surface 124 a of the light-shielding film 124. In addition, the reflected light of the exposed light irradiated to the side surface 124a of the light-shielding film 124 is irradiated to the resist layer after the intensity is weakened by the second low-reflection film 126. This makes it possible to suppress the intensity when the light exposed from the oblique direction of the light source side to the side 124a of the light-shielding film 124 is irradiated to the resist layer by the first low-reflection film 122 and the second low-reflection film 126.

Therefore, as the light-shielding pattern having an optical density (OD) of 4.5 or more with respect to the light in the wavelength region, as shown in FIGS. 5 and 6, it is preferable that it is the side surface of the first low-reflection film or the second low-reflection film. The side surface of the film protrudes in a direction parallel to the surface of the transparent substrate with respect to the side surface of the light-shielding film. The reason is that in order to make the optical density (OD) equal to or greater than 4.5, the light-shielding pattern is made into a thick film. Thus, although the light reflected from the light emitted from the oblique direction of the light source side to the side of the light-shielding film is reflected. The amount of light is increased, but the influence of the reflected light can suppress unevenness in the pattern transferred to the transfer target.

In addition, the side surface of the first low-reflection film or the side surface of the second low-reflection film is defined as one that protrudes in a direction parallel to the surface of the light-transmitting substrate with respect to the side surface of the light-shielding film. There is no particular limitation on one of the protrusions, but it is preferable that both of the sides protrude.

Furthermore, the side surface of the first low-reflection film or the side surface of the second low-reflection film is shown in FIG. 5 and FIG. 6 as a side protruding from the side of the light-shielding film in a direction parallel to the surface of the transparent substrate. Among them, it is preferable that the protrusion lengths represented by L1 and L2 are 1/2 or more of the film thickness of the light-shielding film. The reason for this is that, by the influence of the reflected light described above, it is possible to effectively suppress unevenness in the pattern transferred to the object to be transferred.

In addition, the protruding length means that the side of the first low-reflection film or the side of the second low-reflection film is farthest from the opening of the light-shielding pattern from the concave side surface of the light-shielding film, and the distance The length of the surface of the translucent substrate protruding in parallel to the surface.

In the present invention, it is preferable that the side surface of the first low-reflection film or the side surface of the second low-reflection film is parallel to the surface of the light-transmitting substrate with respect to the side surface of the light-shielding film for the following reasons. Protrude in direction.

That is, in general, a metal film such as chromium has a higher polarity than an oxidized metal film such as a chromium oxide, and therefore, foreign matter tends to be easily attached. Therefore, when the light-shielding film is chromium, if the side surface of the light-shielding film is parallel to the side of the first low-reflection film or the side of the second low-reflection film, Protrusion in the direction increases the possibility of foreign matter adhesion to the light-shielding film, and it may be difficult to remove the foreign matter by subsequent cleaning.

From the viewpoint of attachment of such foreign matter, it is also preferable that the side surface of the first low-reflection film or the side surface of the second low-reflection film is parallel to the side of the light-shielding film in a direction parallel to the surface of the translucent substrate. On the top, it is particularly preferred that both of these sides stand out.

In the present invention, as the order of side surfaces protruding in a direction parallel to the surface of the light-transmitting substrate, it is preferable that the side surface of the first low-reflection film protrudes most, followed by the side surface of the second low-reflection film and light-shielding. The order of the sides of the sex film. The reason is that, when the foreign matter exists near the sides of the multilayer body, the side of the first low-reflection film is most prominent, so the area where the foreign matter contacts the metal oxide film is large, so it is easy to contact. As a result, Foreign matter is also easily peeled.

On the other hand, in the present invention, at least the side surface of the first low-reflection film protrudes in a direction parallel to the surface of the transparent substrate with respect to the side surface of the light-shielding film, and the first low-reflection film is more preferable. The angle of the side surface of the film with respect to the surface of the transparent substrate is 56 ° or less.

FIG. 12 shows part of an example of a large photomask in this state. In the large photomask 100 shown in FIG. 12, the side surface 122 a of the first low-reflection film 122 and the side surface 126 a of the second low-reflection film 126 are opposite to the side surface 124 a of the light-shielding film 124 on the surface 110 a of the light-transmitting substrate 110. Protrude in a parallel direction. The angle α formed by the side surface 122 a of the first low-reflection film 122 and the surface 110 a of the transparent substrate 110 is an angle of 56 ° or less.

As described above, since the angle of the side surface of the first low-reflection film with respect to the surface of the light-transmitting substrate is 56 ° or less, the contact area of the cleaning fluid during cleaning can be increased even when foreign matter is attached. Therefore, cleaning can be performed efficiently, and abnormality caused by the presence of foreign matter after the cleaning step can be prevented.

The angle of the side surface of the first low-reflection film with respect to the surface of the transparent substrate refers to a position A where the side surface 122a of the first low-reflection film 122 is in contact with the surface 110a of the transparent substrate 110. A straight line is connected to the position B where the film thickness of the first low-reflection film 122 starts to decrease, and an angle obtained by measuring the angle between the straight line and the surface 110a is measured.

In addition, the protrusion of the side surface 122a of the first low-reflection film 122 with respect to the side surface 124a of the light-shielding film 124 means a position B where the film thickness of the first low-reflection film 122 starts to decrease with respect to the side surface 124a of the light-shielding film 124. Projecting in a direction parallel to the surface 110 a of the light-transmitting substrate 110.

In the present invention, the angle of the side surface of the first low-reflection film with respect to the surface of the transparent substrate is preferably 56 ° or less, and particularly preferably 40 ° or less. The reason is that cleaning can be performed more efficiently. In addition, although the smaller angle is preferable, it is preferably 20 ° or more from the viewpoint of manufacturing difficulty in actual manufacturing.

In the present invention, it is preferable that the side surface of the second low-reflection film also protrudes in a direction parallel to the surface of the translucent substrate than the side surface of the light-shielding film. The reason is that it is possible to reduce the adhesion of foreign matter to the side surface of the light-shielding film, and the light-shielding film may be difficult to remove the foreign matter by washing due to the influence of the adhesion with the foreign matter.

In the large photomask 100 shown in FIGS. 6 and 7, the side surface 124 a of the light-shielding film 124 is concave. Therefore, when the pattern is transferred to the exposure of the resist layer of the object to be transferred, the reflected light of the exposed light (stray light) irradiated from the oblique direction of the light source side to the side 124a of the light-shielding film 124 is induced. The possibility of reaching the light source side or the opening 120c side of the light shielding pattern 120 increases. Accordingly, it is possible to suppress the reflected light from being irradiated on the resist layer that blocks the exposure of the exposed light by the edge portion of the light-shielding pattern 120. Thereby, the occurrence of dimensional deviation and the like in the pattern on the resist layer transferred to the edge portion can be suppressed.

Therefore, as the light-shielding pattern having an optical density (OD) of 4.5 or more with respect to the light in the wavelength region, as shown in FIGS. 6 and 7, it is preferable that the side surface of the light-shielding film is concave. The reason is that in order to make the optical density (OD) equal to or greater than 4.5, the light-shielding pattern is made into a thick film. Thus, although the light reflected from the light emitted from the oblique direction of the light source side to the side of the light-shielding film is reflected. The amount of light is increased, but the influence of the reflected light can suppress the occurrence of dimensional deviation and the like in the pattern transferred to the object to be transferred.

Furthermore, as the light-shielding pattern in which the side surface of the light-shielding film is concave, in FIGS. 6 and 7, it is preferable that the concave width of the side surface of the light-shielding film shown by W1 and W2 is the same as that of the light-shielding film. The film thickness is 1/2 or more. This is because the influence of the above-mentioned reflected light can effectively suppress the occurrence of dimensional deviations in the pattern transferred to the object to be transferred.

In addition, the recessed width refers to a distance from a position closest to the opening of the light-shielding pattern to a position farthest from the side of the light-shielding film in a direction parallel to the surface of the light-transmitting substrate. width.

d. Interfacial structure of the low-reflection film and the light-shielding film The boundary between the light-shielding film and the first low-reflection film and the second low-reflection film may be a clear boundary or an ambiguous boundary. From the viewpoint of easily controlling the characteristics of each film individually, a light-shielding pattern having a clear boundary as described above is preferred. In addition, from the viewpoint that the processed surface is smooth or can be easily produced, it is preferable to have a light-shielding pattern having the above-mentioned unclear boundary.

The light-shielding pattern having the above-mentioned clear boundary can be produced by separately forming the first low-reflection film, the light-shielding film, and the second low-reflection film using a sputtering device that has been replaced with a gas. In addition, the light-shielding pattern having the unclear boundary can be produced by continuously forming the first low-reflection film, the light-shielding film, and the second low-reflection film without changing the sputtering device gas. membrane.

e. Forming method As the forming method of the above-mentioned light-shielding pattern, for example, the following methods may be mentioned: a first low-reflection film, a light-shielding film, and a second low-reflection film are laminated on the surface of synthetic quartz glass in this order After the light-shielding layer of the laminated structure is formed, a resist pattern of a desired shape is formed on the surface of the light-shielding layer, and the light-shielding layer is processed by wet etching with the resist pattern as a mask.

2. The size of the light-transmitting substrate is the size of the light-transmitting substrate. For example, as long as it can be formed into a photomask having a size of at least 350 mm on at least one side, it can be appropriately selected according to the application of the large photomask of the present invention. It is particularly limited, but it is preferably 330 mm × 450 mm or more, and among them, it is preferably within a range of 330 mm × 450 mm to 1700 mm × 1800 mm.

The film thickness of the light-transmitting substrate can be appropriately selected according to the material, application, and the like of the large-scale mask. The film thickness of the transparent substrate is, for example, about 8 mm to 17 mm.

As the light-transmitting substrate, it is a light-transmitting substrate having a light-transmitting property, and a general large-scale photomask can be used. Examples of the light-transmitting substrate include low-expansion glass (aluminoborosilicate glass, borosilicate glass) and synthetic quartz glass after optical polishing. In the present invention, it is preferable to use synthetic quartz glass. The reason for this is that its thermal expansion rate is small, and it is easy to manufacture a large photomask. Moreover, in the present invention, the above-mentioned translucent substrate made of resin may be used.

The light transmittance of the light-transmitting substrate is not particularly limited as long as it is the same as that of a light-transmitting substrate used in an ordinary large-sized photomask, but it is preferably a light transmittance in a wavelength range of 313 nm to 436 nm. 80% or more, 85% or more is preferable, and 90% or more is more preferable. The reason is that the light passing through the translucent substrate with higher purity has less scattering in the material, and the refractive index is also lower, so the generation of stray light can be suppressed.

3. Other large-sized photomasks according to the present invention include the light-transmitting substrate and the light-shielding pattern, as long as the reflectance of light facing the wavelength region on the light-transmitting substrate side of the light-shielding pattern is 8% or less. It is not particularly limited, but it is preferable to have a division pattern for division exposure, and the division pattern is the light-shielding pattern.

Split exposure refers to the method of dividing the transferred area into a plurality of exposed areas in the transferred body, using a large mask to individually expose each of the plurality of exposed areas, and by turning the divided pattern of the mask It is printed on each of the plurality of exposed areas, and a continuous pattern larger than the divided pattern of the photomask is formed on the transferred body.

Such a preferred large-size mask will be described with reference to the drawings. Fig. 8 is a schematic plan view showing another example of the large-sized photomask of the present invention. FIG. 9 is a schematic plan view showing a pattern transfer body produced from a transfer target using the large mask shown in FIG. 8. 10 (a) to 10 (b) are cross-sectional views schematically showing steps in manufacturing steps of a part of the pattern transfer body shown in FIG.

As shown in FIG. 8, the large-sized photomask 100 includes a translucent substrate 110 and mutually different first, second, and third division patterns 150 a, 150 b, and 150 c provided on the surface 110 a of the translucent substrate 110. The first divided pattern 150a, the second divided pattern 150b, and the third divided pattern 150c are the same as the light-shielding pattern 120 shown in FIG. 1, respectively, and include a first low-reflection film 122, a light-shielding film 124, and a second low-reflection film 126. The light-shielding pattern 120 having a laminated structure in which the transparent substrate 110 is laminated in this order. Therefore, the surfaces of the light-transmitting substrate 110 side of the first divided pattern 150a, the second divided pattern 150b, and the third divided pattern 150c are the same as the light-shielding pattern 120 shown in FIG. The reflectance of light is 8% or less.

Regarding the pattern transfer body 200 ′ shown in FIG. 9, the large-scale reticle 100 shown in FIG. 8 is used, and the first divided pattern 150a, the first Each of the two-divided pattern 150b and the third-divided pattern 150c is manufactured by exposure from a light source (UV lamp) that emits light including exposure of any one of the above-mentioned wavelength regions.

When the pattern transfer body 200 'is manufactured, first, in the first exposure, the second divided pattern 150b and the third divided pattern 150c are shielded by using an exposure shielding plate 300 (as shown in FIG. 10), and The above-mentioned exposed light is irradiated to the resist layer 220 only through the first division pattern 150 a among the first to third division patterns. Then, in the second to sixth exposures, the third divided pattern 150c and the first divided pattern 150a are shielded by the exposure masking plate 300, and only the second divided pattern 150b of the first to third divided patterns is passed. The resist layer 220 is irradiated with the exposure light. Then, in the seventh exposure, the first divided pattern 150a and the second divided pattern 150b are shielded by the exposure masking plate 300, and only the third divided pattern 150c among the first to third divided patterns is applied to the resist layer. 220 irradiates the above-mentioned exposed light. Thereby, one first resist pattern 220a to which the first divided pattern 150a is transferred, five second resist patterns 220b to which the second divided pattern 150b is transferred, and one to which the third divided pattern 150c is transferred The third resist patterns 220c are formed so as to be connected in a single direction. As a result, a continuous single resist pattern is formed.

In the second exposure, as shown in FIG. 10 (a), the same steps as those shown in FIG. 2 are performed, and the light-transmitting substrate 110 in the second division pattern 150 b (light-shielding pattern 120) due to the light of the exposure is reduced. The intensity of the stray light generated by the reflection of the side surface 120a can reduce the stray light La on the resist layer 220 that was originally irradiated on the shielding area (the third exposure area) that was blocked by the exposure shielding plate 300 to block the exposure light. strength. In addition, by reducing the intensity of the stray light caused by the reflection of the above-mentioned exposed light on the surface 120b on the side opposite to the light-transmitting substrate 110 of the second divided pattern 150b, it is possible to reduce the edge originally irradiated with the second divided pattern 150b. The intensity of the stray light Lb on the resist layer 220 in the second exposure area that partially blocks the exposure of the exposed light.

In the third exposure, as shown in FIG. 10 (b), similar to the second exposure, by reducing the intensity of the stray light, the area exposed to the stray light La in the second exposure can be reduced and then irradiated. The intensity of the stray light Lb on the resist layer 220 can reduce the intensity of the stray light La on the resist layer 220 in the area exposed to the stray light Lb in the second exposure.

Therefore, according to the above-mentioned preferred large-sized mask, in the divided exposure, when each of the plurality of exposed areas of the object to be transferred is individually exposed using the large-sized mask, the exposed light is reflected by each face of the light-shielding pattern The stray light generated is irradiated to other exposed areas. Therefore, even when multiple exposures of the stray light are generated on the resist layer, the intensity of the stray light can be reduced. Therefore, unevenness or dimensional deviation in the pattern transferred to the object to be transferred can be significantly suppressed.

Furthermore, in the divided exposure, multiple exposures may occur due to the influence of the alignment accuracy of the exposure device in the portions where adjacent exposure areas are connected. Therefore, when the above-mentioned multiple exposure of stray light occurs, the problem of unevenness or dimensional deviation in the pattern transferred to the object to be transferred tends to become larger. Therefore, the above-mentioned effects can be more clearly obtained.

4. Manufacturing method of large-sized photomask As the manufacturing method of large-sized photomask of the present invention, as long as a large-sized photomask having the above-mentioned structure can be manufactured, it is not particularly limited, and may be the same as the manufacturing method of a general large-sized photomask.

For example, a synthetic quartz glass is prepared as a light-transmitting substrate, and a mask substrate having a light-shielding layer is prepared. The light-shielding layer has a first low-reflection film, a light-shielding film, and a second low-reflection film on the surface of the synthetic quartz glass. A layered structure obtained by stacking in this order. Then, a resist pattern having a desired shape is formed on the surface of the light-shielding layer, and the light-shielding layer is processed by wet etching using the resist pattern as a mask to form a light-shielding pattern according to the light-shielding layer. Thereby, a large photomask is produced.
The etching solution used for the wet etching is not particularly limited as long as the light-shielding layer can be processed with high accuracy and the transparent substrate is not damaged. For example, an ammonium cerium nitrate solution can be used.

5. Use The large photomask of the present invention can be preferably used in, for example, a photolithography method when manufacturing a pattern transfer body of a functional element for a display device used in a display device.

Examples of functional elements for display devices manufactured using the large-sized photomask of the present invention include TFT substrates, metal wiring substrates for TFT substrates, etc., color filters, and light shielding with color filters. Department of substrates and so on.

The method for manufacturing a pattern transfer body such as a functional element for a display device using a large-sized photomask of the present invention is not particularly limited, and may be the same as a general manufacturing method using a large-sized photomask manufacturing method. For example, there can be mentioned a production method including an exposure step and a development step. The exposure step is to prepare a transfer target having a resist layer, irradiate the exposed light through a large photomask, and expose the resist layer. The step is developing the above-mentioned resist layer after exposure.

The resist used as the above-mentioned resist may be the same as a common resist, and may be a positive resist or a negative resist. Examples of the positive resist include a phenol resin, a phenol epoxy resin, an acrylic resin, polyimide, and a cycloolefin. Specific examples include IP3500 (manufactured by TOK (Tokyo Ohka Kogyo)), PFI27 (manufactured by Sumitomo Chemical Co., Ltd.), ZEP7000 (manufactured by Ruiwon), and positive resist (manufactured by JSR) )Wait. Among them, a positive resist (manufactured by JSR) is preferred. The reason for this is that the effect of the present invention is significant because the sensitivity is high. On the other hand, examples of the negative resist include acrylic resins and the like. Specific examples include polyglycidyl methacrylate (PGMA), chemically amplified SAL601 (manufactured by CYPRES), and negative resist (manufactured by JSR). Among them, a negative resist (manufactured by JSR) is preferred. The reason for this is that the effect of the present invention is significant because the sensitivity is high. When a functional element for a display device manufactured using the large-sized photomask of the present invention uses a developed resist layer as a constituent member, the resist layer may contain colorants such as pigments and dyes, and inorganic oxide particles. And other functional materials.

The thickness of the resist layer is not particularly limited, and is, for example, within a range of 10 nm to 10 μm. As for the method for forming the resist layer, a well-known method can be used, and therefore description thereof is omitted here.

The transfer target usually has a substrate for forming a resist layer. Moreover, it may have a metal layer and the like. The material to be transferred is appropriately selected according to the type of the functional element for a display device to be manufactured.

As the exposure light used in the above exposure step, the resist in the resist layer can react, and it is not particularly limited as long as it is any light in a wavelength range of 313 nm to 436 nm. The exposure light is preferably exposure light including light of a plurality of wavelengths such as g-line, h-line, and i-line, and particularly preferably exposure light including j-line. The reason is that the energy of the light radiated to the resist layer can be increased, the exposure can be completed in a shorter exposure time, and unevenness in the pattern transferred to the transferred body can be significantly suppressed. As a light source of the above-mentioned exposure light, for example, an ultra-high pressure mercury lamp (ultra-high pressure UV lamp) or the like can be used.

As a developing method of the resist layer used in the above-mentioned developing step, a general method can be used and is not particularly limited. As the developing method, for example, a method using a developing solution or the like can be preferably used.

The present invention is not limited to the embodiments described above. The above-mentioned embodiment is an example. It has the technical ideas described in the patent application scope of the present invention and substantially the same structure. Anyone who exerts the same effect belongs to the technical scope of the present invention.
[Example]

A. Reflectivity and Optical Density First, the reflectance and optical density using examples and comparative examples will be described.

[Example A1]
First, a photomask substrate is prepared, which includes: synthetic quartz glass (light-transmitting substrate) made by precision grinding of vertical × horizontal × film thickness of 700 mm × 800 mm × 8 mm; and a light shielding layer, which It has a chromium oxide film (CrOx) (first low reflection film) with a thickness of 30 nm, a chromium film (Cr) (light-shielding film) with a thickness of 85 nm, and a chromium oxide with a thickness of 30 nm on the surface of synthetic quartz glass. Film (CrOx) (second low-reflection film) is a laminated structure obtained by laminating in this order.

In the production of the mask substrate, the light-shielding layer is in the order of a chromium oxide film (first low-reflection film), a chromium film (light-shielding film), and a chromium oxide film (second low-reflection film) by using a sputtering method. Formed on the surface of synthetic quartz glass. At this time, the film formation of the chromium oxide film (the first low-reflection film), the chromium film (the light-shielding film), and the chromium oxide film (the second low-reflection film) was performed individually using a sputtering apparatus in which the gas was replaced. In addition, the chromium oxide film (the first low-reflection film) and the chromium oxide film (the second low-reflection film) are those in which a Cr target is installed in a vacuum chamber, and O ₂ , N ₂ , and CO ₂ gases are introduced. Film formed by reactive sputtering. Compared with the film formation conditions of the low-reflection film in the light-shielding pattern of the ordinary binary mask, the ratio of the O ₂ gas is increased in the film formation conditions of the chromium oxide film (the first low-reflection film). The film formation conditions of the chromium oxide film (second low-reflection film) are the same as the film formation conditions of the low-reflection film in the light-shielding pattern of the ordinary binary mask. Furthermore, the film formation conditions of the chromium film (light-shielding film) are the same as the film formation conditions of the chromium film in the light-shielding pattern of the ordinary binary mask.

Then, a resist pattern having a desired shape is formed on the surface of the light-shielding layer, and the light-shielding layer is processed by wet etching with the resist pattern as a mask. According to the light-shielding layer, a light-shielding pattern having a width of 3.0 μm having a width of 0.1 is formed. A light-shielding pattern having a width of 1 μm or more and less than 10.0 μm. Thereby, a large photomask is produced.

[Example A2]
First, a photomask substrate is prepared, which includes: synthetic quartz glass (light-transmitting substrate) made by precision grinding of vertical × horizontal × film thickness of 700 mm × 800 mm × 8 mm; and a film thickness of 180 nm The light-shielding layer has a laminated structure in which a chromium oxide film (first low-reflection film), a chromium film (light-shielding film), and a chromium oxide film (second low-reflection film) are laminated on the surface of a synthetic quartz glass in this order. .

In the production of the mask substrate, the light-shielding layer is in the order of a chromium oxide film (first low-reflection film), a chromium film (light-shielding film), and a chromium oxide film (second low-reflection film) by using a sputtering method Formed on the surface of synthetic quartz glass. At this time, the film formation of the chromium oxide film (the first low-reflection film), the chromium film, and the chromium oxide film (the second low-reflection film) is performed continuously without changing the gas of the sputtering device. In addition, the chromium oxide film (the first low-reflection film) and the chromium oxide film (the second low-reflection film) are those in which a Cr target is installed in a vacuum chamber, and O ₂ , N ₂ , and CO ₂ gases are introduced. Film formed by reactive sputtering. Compared with the film formation conditions of the low reflection film in the light-shielding pattern of the ordinary binary mask, the film formation conditions of the chromium oxide film (the first low reflection film) and the chromium oxide film (the second low reflection film) increase O ₂ Gas ratio. Furthermore, the film formation conditions of the chromium film (light-shielding film) are the same as the film formation conditions of the chromium film in the light-shielding pattern of the ordinary binary mask.

Then, a resist pattern having a desired shape is formed on the surface of the light-shielding layer, and the light-shielding layer is processed by wet etching with the resist pattern as a mask. According to the light-shielding layer, a light-shielding pattern having a width of 3.0 μm having a width of 0.1 is formed. A light-shielding pattern having a width of 1 μm or more and less than 10.0 μm. Thereby, a large photomask is produced.

[Example A3]
First, a photomask substrate is prepared, which includes: synthetic quartz glass (light-transmitting substrate) made by precision grinding of vertical × horizontal × film thickness of 700 mm × 800 mm × 8 mm; and a light shielding layer, which It has a chromium oxide film (first low reflection film) with a thickness of 30 nm, a chromium film (light-shielding film) with a film thickness of 110 nm, and a chromium oxide film (second low reflection) with a film thickness of 30 nm on the surface of synthetic quartz glass. Film) is a laminated structure obtained by laminating in this order.

In the production of the mask substrate, the light-shielding layer is in the order of a chromium oxide film (first low-reflection film), a chromium film (light-shielding film), and a chromium oxide film (second low-reflection film) by using a sputtering method. Formed on the surface of synthetic quartz glass. At this time, the film formation of the chromium oxide film (the first low-reflection film), the chromium film (the light-shielding film), and the chromium oxide film (the second low-reflection film) was performed individually using a sputtering apparatus in which the gas was replaced. In addition, the chromium oxide film (the first low-reflection film) and the chromium oxide film (the second low-reflection film) are those in which a Cr target is installed in a vacuum chamber, and O ₂ , N ₂ , and CO ₂ gases are introduced. Film formed by reactive sputtering. Compared with the film formation conditions of the low reflection film in the light-shielding pattern of the ordinary binary mask, the film formation conditions of the chromium oxide film (the first low reflection film) and the chromium oxide film (the second low reflection film) increase O ₂ Gas ratio. Furthermore, compared to the film formation conditions of the chromium film in the light-shielding pattern of the ordinary binary mask, the film formation conditions of the chromium film (light-shielding film) are prolonged.

Then, a resist pattern having a desired shape is formed on the surface of the light-shielding layer, and the light-shielding layer is processed by wet etching with the resist pattern as a mask. According to the light-shielding layer, a light-shielding pattern having a width of 3.0 μm having a width of 0.1 is formed. A light-shielding pattern having a width of 1 μm or more and less than 10.0 μm. Thereby, a large photomask is produced.

[Comparative Example A]
First, a photomask substrate is prepared, which includes: synthetic quartz glass (light-transmitting substrate) made by precision grinding of vertical × horizontal × film thickness of 700 mm × 800 mm × 8 mm; and a light shielding layer, which It has a laminated structure in which a chromium film (light-shielding film) with a thickness of 85 nm and a chromium oxide film (low reflection film) with a thickness of 30 nm are laminated on the surface of synthetic quartz glass in this order.

In the production of the mask substrate, the light-shielding layer is formed by forming a film on the surface of the synthetic quartz glass in the order of a chromium film (light-shielding film) and a chromium oxide film (low-reflection film) using a sputtering method. At this time, the film formation of a chromium film (light-shielding film) and a chromium oxide film (low-reflection film) was performed individually using the sputtering apparatus which replaced the gas. In addition, a chromium oxide film (low reflection film) is formed by mounting a Cr target in a vacuum chamber, introducing O ₂ , N ₂ , and CO ₂ gas, and performing reactive sputtering in a vacuum environment. The film formation conditions of the chromium oxide film (low reflection film) are the same as the film formation conditions of the low reflection film in the light-shielding pattern of the ordinary binary mask. Further, the film formation conditions of the chromium film are the same as the film formation conditions of the chromium film in the light-shielding pattern of the ordinary binary mask.

Then, a resist pattern having a desired shape is formed on the surface of the light-shielding layer, and the light-shielding layer is processed by wet etching with the resist pattern as a mask. According to the light-shielding layer, a light-shielding pattern having a width of 3.0 μm having a width of 0.1 is formed. A light-shielding pattern having a width of 1 μm or more and less than 10.0 μm. Thereby, a large photomask is produced.

[Evaluation results]
a. Observation of the interface structure between the low-reflection film and the light-shielding film The SEM (Scanning Electron Microscope) was used to observe the low-reflection film and the light-shielding film of the light-shielding pattern in Examples A1 to A3 and Comparative Example A. Junction structure. As a result, in the boundary between the light-shielding patterns in Examples 1 and 3, the content ratio of Cr discontinuously changed, and the boundary between the chromium oxide film (the first low-reflection film) and the chromium film (the light-shielding film) and the chromium film ( The boundary between the light-shielding film) and the chromium oxide film (second low-reflection film) becomes clear. In the boundary of the light-shielding pattern in Example 2, the content ratio of Cr continuously changes, and the boundary between the chromium oxide film (the first low-reflection film) and the chromium film (light-shielding film) and the chromium film (light-shielding film). The boundary with the chromium oxide film (second low-reflection film) is unclear. In the boundary of the light-shielding pattern in the comparative example, the content ratio of Cr was discontinuously changed, and the boundary between the chromium film (light-shielding film) and the chromium oxide film (low-reflection film) became clear.

b. Back and surface reflectance and optical density (OD) of the light-shielding pattern
Regarding the large photomasks of Examples A1 to A3 and Comparative Example A, the back surface reflectance (reflectance of the surface on the side of synthetic quartz glass) of the light shielding pattern to light in a wavelength range of 313 nm to 436 nm and the light shielding pattern to the above were measured. The surface reflectance of light in the wavelength region (the reflectance of the surface opposite to the synthetic quartz glass) and the optical density (OD) of the light-shielding pattern with respect to the light in the above-mentioned wavelength region.

The back surface reflectance and the surface reflectance are measured using a spectrometer (Otsuka Electron MCPD3000) in the range of the wavelength region in units of 1 nm. The above-mentioned optical density (OD) is measured every 1 nm using a UV / visible spectrophotometer (Hitachi U-4000) in the range of the above-mentioned wavelength region. Among the measurement results, the measurement results using g-line (wavelength 436 nm), h-line (wavelength 405 nm), i-line (wavelength 365 nm), and j-line (wavelength 313 nm) are shown in Table 3 below.

The measurement conditions of the above-mentioned spectroscopic analyzer (Otsuka Electronics MCPD3000) are summarized in Table 1, and the measurement conditions of the above-mentioned ultraviolet / visible spectrophotometer (Hitachi U-4000) are summarized in Table 2.

[Table 1]

[Table 2]

c. Properties of the resist pattern Using the large photomasks of Examples A1 to A3 and Comparative Example A, for the purpose of forming a resist pattern of a desired shape, a resist layer having a film thickness of 2.5 μm formed on a glass substrate ( (Produced by JSR Co., Ltd.) according to the following exposure conditions, the exposure stepwise (reduction projection type) close-type exposure is performed.

(Exposure conditions)
Exposure gap: 150 μm
Light source: Ultra-high pressure mercury lamp exposure light: exposure light including g-line, h-line, i-line and j-line exposure: 200 mJ / cm ²

As the properties of the resist pattern formed using the large photomasks of Examples A1 to A3 and Comparative Example A, the thickness of the uneven portion of the resist pattern relative to the normal portion varies (hereinafter, sometimes referred to as "uneven portion film" Thick variation "). Specifically, it measures the ratio [%] of the variation of the film thickness of the uneven portion of Examples A1 to A3 when the variation of the film thickness of the uneven portion of Comparative Example A is 100%. The results are shown in Table 3 below.

[table 3]

In Examples A1 to A3, as shown in Table 3 above, for any of the g-line, h-line, i-line, and j-line, the back reflectance is 8% or less. Although not shown in the above Table 3, However, the results are the same for other wavelengths of light in the above-mentioned wavelength region. In Examples A2 and A3, as shown in Table 3 above, the surface reflectance of each of the g-line, h-line, i-line, and j-line is 10% or less, although not shown in Table 3 above. Out, but for other wavelengths of light in the above-mentioned wavelength region, the same result is obtained. In Example A3, as shown in Table 3 above, the optical density (OD) of each of the g-line, h-line, i-line, and j-line was 4.5 or more. Although not shown in Table 3 above, , But for other wavelengths of light in the above-mentioned wavelength region, the same result is obtained. In contrast, in Comparative Example A, as shown in Table 3 above, for the g-line, h-line, i-line, and j-line for the h-line, i-line, and j-line, the back reflectance is greater than 8%, and for the g-line The surface reflectance of any of the H, I, and J lines is greater than 10%, and the optical density (OD) is less than 4.5.

As shown in Table 3 above, in Examples A1 to A3, it was possible to suppress variations in the film thickness of the uneven portion compared to the comparative example. Moreover, in Examples A2 and A3, compared with Example A1, it was possible to effectively suppress variation in film thickness in the uneven portion. Furthermore, in Example A3, compared with Example A2, the variation in film thickness in the uneven portion was significantly suppressed.

B. Reduction of Foreign Matter by Cleaning Next, the effect of reducing foreign matter by cleaning will be described using examples and comparative examples.

[Example B1]
A large photomask was produced in the same manner as in the above-mentioned Example A3.
Use a glass cutter to cut the large photomask to within 20 mm (h) × 30 mm (w) × 8 mm (d). The cut surface was subjected to a sputtering process (20 mA × 12 seconds) with platinum, and observed with an electron microscope. As the electron microscope, a scanning electron microscope (JSM-6700F, manufactured by Japan Electronics Co., Ltd.) was used. The acceleration voltage was set to 5.0 kV, the slope was set to 0 °, and the mode was set to SEI (Secondary Electron Image). (Secondary electron below detection), set the working distance to 3.2 mm to 3.3 mm (fine adjustment according to the sample height), and then set the cumulative number to 1 (Fine View mode), and set the observation magnification to × 100 K. The measurement portion is a portion of a 3.0 μm wide light-shielding pattern.
As a result of the measurement, it was found that the angle of the side surface of the first low-reflection film with respect to the surface of the transparent substrate was 80 °. In addition, as described above, the angle is connected by a straight line at a position where the side surface of the first low-reflection film contacts the surface of the transparent substrate and a position where the film thickness of the first low-reflection film starts to decrease. And measure the angle obtained from the angle between the straight line and the surface.

For such a large photomask of Example B1, clean with pure water for 300 seconds, dry it after implementation, use a reflection inspection of an appearance inspection machine, and determine the number of foreign objects after cleaning by detecting the sensitivity of foreign objects above 1 μm. This measurement value is a value obtained by measuring an area of 690 mm × 790 mm after removing 5 mm of the edges of the four sides of the glass substrate.
The measured values are shown in Table 4 as a ratio when the value of Comparative Example B described later is 100.

[Examples B2 to B5]
The etching conditions of the above-mentioned Example B1 were changed to extend the etching time, and the angle of the side surface of the first low-reflection film with respect to the surface of the translucent substrate was changed to produce large-scale light having the angle shown in Table 4 below. cover. The angle was measured in the same manner as in the above-mentioned Example B1.

The large photomasks were cleaned by the same method as in Example B1, and the number of foreign objects was measured in the same manner. The measured values are shown in Table 4 as a ratio when the value of Comparative Example B described later is 100.

[Comparative Example B]
A large-size mask was produced in the same manner as in Comparative Example A described above.
The angle of the side surface of the first low-reflection film with respect to the surface of the light-transmitting substrate was measured on the obtained large-scale mask in the same manner as in Example B1.
Further, the obtained large photomask was cleaned in the same manner as in Example B1, and the number of foreign objects was measured in the same manner. The results are 100% and are shown in Table 4.

[Table 4]

It is clear from the results in Table 4 that the number of foreign objects in the examples is smaller than that in the comparative examples. The reason is presumably because the chromium film in the comparative example and the difference in affinity between the chromium oxide film and the foreign matter in the example differ.
It is also known that when the angle is changed, the smaller the angle, the smaller the number of foreign objects. In particular, the value greatly changes between Example B2 and Example B3.

100‧‧‧large photomask

110‧‧‧Transparent substrate

110a‧‧‧ surface

112‧‧‧ interface

120‧‧‧ Shading pattern

120a‧‧‧ surface

120b‧‧‧ noodles

120c‧‧‧ opening

122‧‧‧The first low reflection film

122a‧‧‧ side

124‧‧‧Light-shielding film

124a‧‧‧ side

126‧‧‧The second low reflection film

126a‧‧‧side

150a‧‧‧ 1st division pattern

150b‧‧‧ 2nd division pattern

150c‧‧‧The third division pattern

200‧‧‧ transferee

200'‧‧‧ pattern transfer

210‧‧‧ Matrix

212‧‧‧ interface

214‧‧‧ interface

220‧‧‧ resist

220a‧‧‧The first resist pattern

220b‧‧‧Second resist pattern

220c‧‧‧3rd resist pattern

300‧‧‧ exposure mask

300a‧‧‧ surface

A‧‧‧Location

B‧‧‧Location

L1‧‧‧ protruding length

L2‧‧‧ protruding length

La‧‧‧ stray light

Lb‧‧‧ stray light

Lc‧‧‧ through light

W1‧‧‧Recessed width

W2‧‧‧Recessed width

α‧‧‧Tilt angle

FIG. 1 is a schematic cross-sectional view showing an example of a large-sized photomask of the present invention.

FIG. 2 is a schematic cross-sectional view showing a step of transferring a pattern to a resist layer included in a transfer target body by using the large-scale photomask shown in FIG.

FIG. 3 is an enlarged view showing the area within the dotted frame shown in FIG. 1 upside down.

FIG. 4 is a schematic cross-sectional view showing a region corresponding to FIG. 3 in a large-sized photomask of the prior art.

Fig. 5 is a schematic cross-sectional view showing a region corresponding to Fig. 3 in another example of the large-sized photomask of the present invention.

FIG. 6 is a schematic cross-sectional view showing a region corresponding to FIG. 3 in another example of the large-scale mask of the present invention.

FIG. 7 is a schematic cross-sectional view showing a region corresponding to FIG. 3 in another example of the large-sized photomask of the present invention.

Fig. 8 is a schematic plan view showing another example of the large-sized photomask of the present invention.

FIG. 9 is a schematic plan view showing a pattern transfer body produced from a transfer target using the large mask shown in FIG. 8.

10 (a) and 10 (b) are schematic cross-sectional views showing a part of manufacturing steps of the pattern transfer body shown in FIG.

FIG. 11 is a graph comparing a change in transfer line width shift with respect to an exposure amount using an existing low-sensitivity resist and a high-sensitivity resist used in recent years.

FIG. 12 is a schematic cross-sectional view showing a region corresponding to FIG. 3 in another example of the large-sized photomask of the present invention.

Claims (14)

A large photomask, characterized in that it is a large photomask including a light-transmitting substrate and a light-shielding pattern provided on the surface of the light-transmitting substrate. The light-shielding pattern has a laminated structure in which a first low-reflection film, a light-shielding film, and a second low-reflection film are laminated in this order from the transparent substrate side, and The reflectance of light in the wavelength region of 313 nm to 436 nm on the light-transmitting substrate side of the light-shielding pattern is 8% or less. For example, the large-scale photomask of claim 1 is characterized in that the reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-shielding pattern on the side opposite to the light-transmitting substrate is 10% or less. The large-scale photomask of claim 1, wherein the light-shielding film contains chromium, and the first low-reflection film and the second low-reflection film contain chromium oxide. For example, the large-scale photomask of claim 1, characterized in that the reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-shielding pattern on the side opposite to the light-transmitting substrate is 10% or less, and The light-shielding film contains chromium, and the first low-reflection film and the second low-reflection film contain chromium oxide. For example, the large-scale photomask of claim 1, wherein the optical density (OD) of the light-shielding pattern to light in a wavelength range of 313 nm to 436 nm is 4.5 or more. For example, the large-scale photomask of claim 1, characterized in that the reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-shielding pattern on the side opposite to the light-transmitting substrate is 10% or less, and The optical density (OD) of the light-shielding pattern with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. The large photomask of claim 1, wherein the light-shielding film contains chromium, the first low-reflection film and the second low-reflection film contain chromium oxide, and The optical density (OD) of the light-shielding pattern with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. For example, the large-scale photomask of claim 1, characterized in that the reflectance of light in a wavelength region of 313 nm to 436 nm facing the light-shielding pattern on the side opposite to the light-transmitting substrate is 10% or less, The light-shielding film contains chromium, the first low-reflection film and the second low-reflection film contain chromium oxide, and The optical density (OD) of the light-shielding pattern with respect to light in a wavelength region of 313 nm to 436 nm is 4.5 or more. For example, the large-scale photomask of claim 5, wherein the inclination angle of the side surface of the light-shielding film with respect to the transparent substrate is 80 degrees or more and 90 degrees or less. The large photomask of claim 5, wherein the side surface of the first low-reflection film or the side surface of the second low-reflection film is parallel to the side of the light-shielding film in a direction parallel to the surface of the transparent substrate Highlight on. The large photomask of claim 10, wherein both the side surface of the first low-reflection film and the side surface of the second low-reflection film are on the surface of the translucent substrate with respect to the side surface of the light-shielding film Protruding in parallel, and Furthermore, the side surface of the first low-reflection film is more protruded in a direction parallel to the surface of the transparent substrate than the side surface of the second low-reflection film. The large photomask of claim 10, wherein at least the side surface of the first low-reflection film projects in a direction parallel to the surface of the transparent substrate with respect to the side surface of the light-shielding film, Furthermore, the angle of the side surface of the first low-reflection film with respect to the surface of the transparent substrate is 56 ° or less. The large photomask according to claim 5, wherein the light shielding film has a concave side surface. A large-sized photomask, characterized in that it is a large-sized photomask according to any one of claim 1 to claim 13, and has a division pattern for division exposure, and the division pattern is the light-shielding pattern.