TW201940959A - Photomask, photomask blank, method of manufacturing a photomask, and method of manufacturing an electronic device - Google Patents

Abstract

To provide a photomask which is capable of preventing generation of electrostatic brakedown. A photomask 10 has, on a principal surface of a transparent substrate 21, a transfer pattern 35 formed by patterning an optical film, a light-transmitting annular portion 33 surrounding an outer periphery of the transfer pattern 35, and an outer peripheral region 31 surrounding an outer periphery of the light-transmitting annular portion 33. In the outer peripheral region 31, a transparent conductive film 25 is formed on the transparent substrate 21 and, on the transparent conductive film 25, a mark pattern is formed by patterning the optical film.

Description

Photomask, photomask base, photomask manufacturing method, and electronic component manufacturing method

The invention relates to a photomask, a photomask base, a method for manufacturing a photomask, and a method for manufacturing an electronic component.

Photolithography is used in the manufacture of electronic components such as flat panel displays and semiconductor integrated circuits. In the photolithography technology applied to the manufacture of these electronic components, a photomask having a pattern for transfer formed by patterning an optical film such as a light-shielding film on a main surface of a transparent substrate is used.

During the manufacturing process of the photomask or the process of using the photomask, there are situations in which part of the photomask is charged with static electricity due to the contact of the photomask with other equipment or the influence of external electromagnetic waves. When a potential difference due to static electricity is generated between a plurality of isolated parts separated by a minute interval in a transfer pattern, there may be a case where a discharge is generated to damage the pattern and become a defect.

In order to solve the problem of pattern defects caused by the impact of the discharge caused by the charging of the photomask, it is proposed to form an antistatic destruction film with light transmission and conductivity on the photomask substrate, and a light shielding film is provided on the photomask substrate. A photomask base and a photomask formed by patterning the photomask base (Patent Document 1). Furthermore, a photomask substrate has been proposed in which a transparent conductive film is provided on the light-shielding film-forming surface of a glass substrate with an antireflection film interposed therebetween (Patent Document 2).
[Prior technical literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2014-81449
[Patent Document 2] Japanese Patent Laid-Open No. 2014-134667

[Problems to be solved by the invention]

When the photomask of Patent Document 1 is used and pattern transfer is performed by an exposure device, the transmittance of the exposed light is reduced by the antistatic destruction film. Therefore, there is a problem that the time required for exposure in order to obtain the amount of light required for the transfer becomes long, thereby reducing the amount of output.

In the photomask of Patent Document 2, a transparent conductive film is formed by interposing an antireflection film, and the problem of a decrease in transmittance generated in Patent Document 1 is alleviated. However, when the anti-reflection film and the transparent conductive film are formed on the entire surface of the transparent substrate, in-plane unevenness of each of the film thickness or film quality cannot be completely prevented, and therefore there is a problem that in-plane uniformity of optical characteristics cannot be ensured. When the in-plane unevenness of the optical characteristics occurs, the pattern cannot be accurately transferred. In particular, since a photomask for a flat panel display has various sizes including a large area, it is difficult to eliminate in-plane unevenness in film thickness in a film forming apparatus.

In one aspect, the present invention aims to provide a photomask or the like that prevents the occurrence of electrostatic damage.
[Technical means to solve the problem]

(1st aspect)
A first aspect of the present invention is a photomask, which has on a main surface of a transparent substrate:
A pattern for transfer, which is formed by patterning an optical film;
A light-transmitting annular portion surrounding the outer periphery of the transfer pattern; and a peripheral region surrounding the outer periphery of the light-transmitting annular portion; and a transparent conductive film laminated on the main surface in the outer peripheral region; A marking pattern obtained by patterning the optical film.
(Second aspect)
A second aspect of the present invention is the photomask of the first aspect described above, wherein the transparent conductive film is formed between the transparent substrate and the optical film in the outer peripheral region.
(3rd aspect)
A third aspect of the present invention is the photomask according to the first aspect, wherein the optical film is formed between the transparent substrate and the transparent conductive film in the outer peripheral region.
(4th aspect)
The fourth aspect of the present invention is the photomask according to any one of the first aspect to the third aspect, wherein the optical film includes a light-shielding film.
(5th aspect)
A fifth aspect of the present invention is the photomask according to any one of the first aspect to the fourth aspect, wherein an outer edge of the transfer pattern is electrically connected to the transfer pattern and is on the main surface. It is surrounded by a light-shielding annular portion formed by forming the above optical film.
(Sixth aspect)
A sixth aspect of the present invention is the photomask according to the fifth aspect, wherein the light-shielding annular portion has an outer edge parallel to the inner edge of the outer peripheral region.
(Seventh aspect)
The seventh aspect of the present invention is the photomask according to any one of the first aspect to the sixth aspect, wherein the light-transmitting annular portion has a surface with the transparent substrate exposed at a width of 1 mm or more over the entire circumference. Part of it.
(8th aspect)
The eighth aspect of the present invention is the photomask according to any one of the first aspect to the seventh aspect, wherein the mark pattern is an alignment mark used when the photomask is exposed.
(9th aspect)
A ninth aspect of the present invention is a photomask base having a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding the transfer region on the outer peripheral side of the transfer region. And the transparent substrate is exposed on the transfer region,
A transparent conductive film is formed on the transparent substrate in the outer peripheral region.
(Tenth aspect)
A tenth aspect of the present invention is a photomask base having a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding the transfer region on the outer peripheral side of the transfer region. And, in the transfer region, forming an optical film on the transparent substrate to make the pattern for transfer,
In the outer peripheral region, a transparent conductive film and the optical film are laminated on the transparent substrate.
(11th aspect)
An eleventh aspect of the present invention is a method for manufacturing a photomask, which includes:
A step of preparing a photomask substrate, the photomask substrate having a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding an outer periphery of the transfer region, and the transfer region is on the transparent substrate. An optical film is formed, and the outer peripheral region is formed by laminating a transparent conductive film and the optical film on the transparent substrate; and a patterning step of patterning only the optical film; and in the patterning step, forming the above A pattern for transfer, a mark pattern is formed in the outer peripheral region, and a light-transmitting annular portion having a portion of the transparent substrate exposed at a specific width is formed between the pattern for transfer and the outer peripheral region.
(12th aspect)
A twelfth aspect of the present invention is a method for manufacturing a photomask, which includes:
A step of preparing a photomask substrate, the photomask substrate having a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding the outer periphery of the transfer region, and the transfer region and the outer periphery region A laminated film having a transparent conductive film and an optical film formed on the transparent substrate;
The patterning step includes forming the transfer pattern in the transfer region by patterning only the optical film, forming a mark pattern in the peripheral region, and forming a pattern between the transfer pattern and the peripheral region. A light-transmitting annular portion having a portion of the transparent substrate exposed at a specific width is formed in between; and a removing step of removing the transparent conductive film exposed in the transfer region through the patterning step.
(13th aspect)
A thirteenth aspect of the present invention is a method for manufacturing a photomask, which includes:
A step of preparing a photomask intermediate, which is provided on a transparent substrate with a pattern for transfer, which is formed by patterning an optical film, and a peripheral region, which surrounds the outer periphery of the pattern for transfer and has a mark pattern And a light-transmitting annular portion, where a transparent substrate having a specific width is exposed between the transfer pattern and the outer peripheral region; and a step of laminating a transparent conductive film on the outer peripheral region.
(14th aspect)
The fourteenth aspect of the present invention is a method for manufacturing an electronic component, which has the following steps:
The photomask according to any one of the first aspect to the eighth aspect is prepared; and the above-mentioned pattern for transfer is transferred onto a transfer target body using an exposure device.
[Effect of the invention]

According to one aspect of the present invention, it is possible to provide a photomask or the like that prevents generation of static electricity.

[Embodiment 1]
FIG. 1 is a schematic front view of a mask 10 according to the first embodiment of the present invention. In the first embodiment, a large mask 10 used in the manufacture of a flat panel display will be described as an example. The mask 10 of the first embodiment is a flat plate having a main surface of a quadrangle (square or rectangle) with a side of 300 to 2000 mm and a thickness of 5 to 16 mm. Furthermore, in FIG. 1, the outer peripheral area 31 of the mask 10 is exaggeratedly thickened for illustration.

FIG. 2 is an enlarged view of part A of the photomask 10 shown in FIG. 1, and FIG. 3 is a schematic cross-sectional view of the photomask taken along line III-III of FIG. 1.

A transfer pattern 35 is formed on the main surface of the photomask 10 in a plan view. The transfer pattern 35 is formed by patterning an optical film formed on a transparent substrate 21 (see FIG. 3) as a substrate of the photomask 10. Many optical films are formed of a conductive film. For example, by applying a light-shielding film 23 (see FIG. 3) as an optical film, a transfer pattern 35 including a light-transmitting portion and a light-shielding portion can be formed to form a so-called binary mask. In this case, the transparent substrate 21 is exposed in the light transmitting portion. In the light-shielding section, at least a light-shielding film 23 is formed on the transparent substrate 21.

The photomask 10 may be a multi-step photomask having a transfer pattern formed by using the light-shielding film 23 and a translucent film that transmits a part of the exposed light as an optical film and patterning each of them (sometimes also (Called a step mask, or grayscale mask). In this case, it is preferable that the translucent film has a transmittance of about 20 to 60% and a phase shift amount of 60 degrees or less with respect to the representative wavelength of the exposed light.

The reticle 10 may be provided with a phase shift using a phase shift film that transmits a portion of the exposed light and shifts the phase by approximately 180 degrees as an optical film and patterned the phase shift film. Shift the hood. Further, the photomask 10 may be a phase shift photomask having a transfer pattern formed by patterning each of the photomask and the phase shift film as an optical film. In this case, the exposure transmittance of the phase shift film can be set to about 3 to 70%. Here, approximately 180 degrees means a range of 180 ± 30 degrees.

The transfer pattern 35 is a pattern based on the design of the electronic component to be obtained, and is a pattern transferred to the object to be transferred by exposure. In FIGS. 1 and 2, the transfer pattern 35 is shown by hatching. The detailed shape of the transfer pattern 35 is not shown.

The outer edge of the transfer pattern 35 is surrounded by a ring-shaped portion having a specific width. As can be understood from FIG. 1, the “ring shape” in this specification does not only mean a ring shape, but also a frame shape such as a quadrangle. The annular portion is preferably a film including one or more of the patterns 35 for transfer. Hereinafter, a case where the optical film is the light-shielding film 23 will be described as an example. Therefore, this annular portion is referred to as a light-shielding annular portion 34. Here, the light-shielding annular portion 34 is formed by forming the above-mentioned optical film (light-shielding film 23) on the transparent substrate 21. Of course, in the case where the optical film is a phase shift film, the ring-shaped portion may be set to include the phase shift film pattern. When the transfer pattern 35 is a laminate of a plurality of films, this portion can be similarly used as a laminate.

When the outer peripheral shape of the transfer pattern 35 has unevenness or an acute-angled portion, there is a risk that a discharge will occur between the outer peripheral region 31 described below. Therefore, by forming a light shielding ring portion 34 which is electrically connected to the transfer pattern 35 on the outer edge of the transfer pattern 35, the outer edge shape of the transfer pattern 35 can be adjusted to ensure the following light-transmitting ring The function of an appropriate width of the portion 33. In addition, the above-mentioned risk of generating a discharge is reduced. Therefore, it is preferable that the outer edge of the light-shielding annular portion 34 does not include an acute angle or a right angle portion except for the vicinity of the four corners of the transparent substrate 21. Although the shape of the outer edge of the light-shielding annular portion 34 may include a curve, it is preferable to include a straight line parallel to each side of the quadrangle forming the edge of the main surface of the photomask 10 in consideration of convenience in manufacturing (drawing step) It is more preferable to include only the straight line.
In the cross-sectional views shown in FIG. 3 and the like, there is a gap between the transfer pattern 35 and the light-shielding annular portion 34. However, in the photomask 10 of the first embodiment, the transfer pattern 35 is outside it. Any part of the edge is continuous with the light shielding ring portion 34.

A light-transmitting annular portion 33 is formed on the outer peripheral side of the light-shielding annular portion 34. That is, the light-shielding annular portion 34 is adjacent to the light-transmitting annular portion 33, and the outer periphery is surrounded by the light-transmitting annular portion 33. In the first embodiment, the light-transmitting annular portion 33 is formed as a portion having a specific width exposed on the surface of the transparent substrate 21. The width of the light-transmitting annular portion 33 is preferably 1 mm or more, and specifically, it is preferably set to a width of 1 to 5 mm. The light-transmitting annular portion 33 has a function of electrically separating the outer peripheral region described below from the transfer pattern 35. However, if the width is too narrow, the effect of the electrical separation becomes unreliable. On the other hand, if the width of the light-transmitting annular portion 33 is too large, the area of the transfer pattern 35 is restricted.

It is also preferable that the outer edge of the light-transmitting annular portion 33 has no acute or right-angled portions except for the vicinity of the four corners of the transparent substrate 21. The shape of the outer edge of the light-transmitting annular portion 33 can be considered to be the same as that of the light-shielding annular portion 34 described above. That is, it is more preferable to include a straight line parallel to each side of the quadrangle forming the main surface of the mask 10. The light-transmitting annular portion 33 may have a portion having a fixed width over the entire circumference.

An outer peripheral region 31 is formed on the outer peripheral side of the light-transmitting annular portion 33. The outer peripheral region 31 is formed in a ring shape near the outer edge of the principal plane of the mask 10 and surrounds the light-transmitting ring-shaped portion 33. Preferably, the transparent conductive film 25 is formed in the outer peripheral region 31, and an optical film pattern (here, a light-shielding film pattern) is formed thereon. The light-shielding film pattern formed in the outer peripheral region 31 includes, for example, the following mark patterns.

Here, the optical film (here, the light-shielding film 23) formed in the outer peripheral area 31 may be formed including the outer edge of the main surface of the transparent substrate 21, but it is preferably separated from the outer edge by a specific distance (for example, 1 to 5). Mm).

The light-transmitting annular portion 33 electrically isolates the transfer pattern 35 from the outer peripheral region 31. In order to ensure insulation, the light-transmitting annular portion 33 preferably has a width of 1 mm or more over the entire circumference.

As described above, the light-transmitting annular portion 33 is preferably a shape in which the transparent substrate 21 is exposed. However, the width of the light-transmitting annular portion 33 can be made sufficiently thick to form another pattern in this area. For example, a linear pattern that divides the width of the light-transmitting annular portion 33 into two parts may be provided to double the above-mentioned electrical insulation effect. That is, when this situation is convenient, it is desirable to ensure a width of 1 mm or more as the exposed portion of the transparent substrate 21.

A mark pattern is not formed on the outer peripheral area 31 and is not transferred to the object to be transferred when the photomask is exposed. Here, as an example of a mark pattern, the alignment mark 32 used for positioning of the mask 10 at the time of exposure is shown in FIG.1 and FIG.2. In this way, a plurality of alignment marks 32 can be provided at specific intervals.

In FIG. 1 to FIG. 3, the alignment mark 32 is a shape in which a cross-shaped light-shielding portion is arranged inside the light-transmitting portion of the quadrangle. Here, the cross-shaped light-shielding portion is isolated into an island shape as a pattern shape in the peripheral region 31. In the case where such an isolated portion is also electrically isolated, there is a risk that an electrostatic discharge may occur between the isolated portion and a light-shielding film pattern (the light-shielding film 23 in the peripheral region 31) near the isolated portion, which may cause electrostatic damage. However, in the first embodiment, the isolated portion and the light-shielding film pattern located in the vicinity are electrically connected by the transparent conductive film 25, so that the effect of the present invention that prevents electrostatic damage due to discharge can be obtained. This effect will be described in detail below.

Furthermore, the shape and number of the alignment marks 32 are examples, and any shape and any number of the alignment marks 32 may be provided. As the mark pattern, in addition to the above-mentioned alignment mark 32, identification or display of a product or a manufacturer may be provided. The function and content of the mark pattern are unlimited. These marking patterns have various designs according to their functions, but in any case, according to the present invention, the risk of inducing electrostatic damage can be avoided.

The structure of the mask 10 according to the first embodiment will be further described with reference to FIGS. 1 to 3.

The photomask 10 is formed by patterning a transparent conductive film 25 and an optical film (here, the light-shielding film 23) formed on one main surface of the transparent substrate 21.

The transparent substrate 21 is obtained by flatly and smoothly polishing a substrate of a transparent material such as synthetic quartz glass or soda lime glass. It is preferable that the transparent substrate 21 transmits at least 90% of light having a representative wavelength included in the exposure light used for the exposure of the photomask 10.

As the exposure light, if it is an exposure device for manufacturing a semiconductor device, light sources such as i-ray, KrF excimer laser, and ArF excimer laser can be used. In the case of an exposure device for manufacturing a flat panel display, a light source having any wavelength of i-ray, h-ray, and g-ray, or a wavelength region including i-ray to g-ray can be used.

The transfer pattern 35 is a pattern including an optical film pattern designed according to an electronic component to be obtained using the photomask 10, and here, it is directly formed on a transparent substrate. According to the manufacturing steps of the transfer pattern 35, a pattern can be formed by patterning one optical film, or by patterning and stacking a plurality of optical films, respectively. The transfer pattern 35 may be, for example, a pattern including the light-shielding film 23, or a pattern formed with the light-shielding film 23 or a translucent film or a phase shift film in place of the light-shielding film 23. The transfer pattern 35 may include a phase shifter in which an etched portion is formed on the surface of the transparent substrate 21 together with any of the optical film patterns described above.

In the photomask 10 shown in FIG. 3, the light-shielding film 23 constituting the transfer pattern 35 has conductivity. The light shielding film 23 may be a film containing a metal such as chromium, tantalum, molybdenum, titanium, or tungsten. For example, the light-shielding film 23 may be a film including the above-mentioned metal, or an oxide, nitride, carbide, oxynitride, or oxycarbonitride. The light-shielding film 23 may be a metal silicide containing a metal such as tantalum or molybdenum, or an oxide, nitride, carbide, oxynitride, or oxycarbonitride. The light-shielding film 23 does not substantially transmit the light of the exposure. For example, the optical density OD (Optical Density) can be set to 3 or more, and more preferably 5 or more.

In the light-shielding annular portion 34, the light-shielding film 23 is formed in a ring shape on the transparent substrate 21 to surround the transfer pattern 35. As described above, the light-shielding film 23 constituting the transfer pattern 35 and the light-shielding film 23 constituting the light-shielding annular portion 34 are electrically continuous. Alternatively, the boundary between the transfer pattern 35 and the light-shielding annular portion 34 may not be recognized.

In the light-transmitting annular portion 33, a film is not laminated on the transparent substrate 21 and the transparent substrate 21 is exposed.

In the peripheral region 31, a transparent conductive film 25 is formed on the transparent substrate 21, and an alignment mark 32 including a light-shielding film pattern is formed thereon. The alignment mark 32 includes a light transmitting portion and a light shielding portion. A light-shielding film 23 is not laminated on the transparent conductive film 25 formed on the transparent substrate 21 in the light-transmitting portion, and a light-shielding film 23 is laminated on the transparent conductive film 25 in the light-shielding portion.

The transparent conductive film 25 is, for example, an ITO (Indium Tin Oxide) film, a ZnO (zinc oxide) film, a SnO ₂ (tin oxide) film, an In ₂ O ₃ (indium oxide) film, and other than In. _x SnYO _z film, Sn _x SbYO _z film and other films that have translucency and conductivity. The transparent conductive film 25 has, for example, a transmittance of i rays, h rays, or g rays of 85% or more, preferably 90% or more, and the sheet resistance value is preferably 10 MΩ / □ or less. The thickness of the transparent conductive film 25 is preferably 20 nm or less. A Ta _X O _Y (tantalum oxide) film as a transparent protective layer may be laminated on the transparent conductive film. In this case, as the laminated film, it is preferable to satisfy the above-mentioned film thickness, transmittance, and conductivity.

The transparent conductive film 25 may be accompanied by an anti-reflection film on the transparent substrate 21 side. The antireflection film has a function of increasing the transmittance of the exposed light by laminating the transparent conductive film 25. The material of the transparent conductive film 25 is preferably one having permeability and conductivity, and examples thereof include those containing Si ₃ N ₄ and ZrO ₂ as main components. In the case of a laminated structure, the laminated film preferably satisfies the above-mentioned film thickness and conductivity as a whole, and the light transmittance is preferably 90% or more.

The transparent conductive film 25 slightly reduces the light transmittance of the light transmitting portion in the peripheral region 31, but there is no problem in identifying the mark patterns such as the alignment mark 32. On the other hand, in the transfer pattern 35, since the transmittance of the light-transmitting portion does not decrease, the transfer of the fine pattern can be performed delicately.

The transparent conductive film 25 is preferably a material having resistance to the etchant of the light-shielding film 23. That is, the transparent conductive film 25 and the light-shielding film 23 preferably have etching selectivity.

Taking a case where a TFT (Thin-Film-Transistor, thin-film transistor) array substrate of a liquid crystal display panel or an organic EL (Electro-Luminescence) display panel is manufactured as an example, the photomask 10 using the first embodiment is manufactured. The outline of the steps of the electronic component will be described.

A TFT substrate prepared by sequentially laminating a metal film and a resist on one surface of a transfer target such as a glass substrate is prepared.

The TFT substrate is set in an exposure device for a flat panel display. The alignment mark 32 is detected by irradiating the peripheral illumination area 31 with alignment illumination light, and positioning is performed.

The transfer pattern 35 is irradiated with light. The exposure light source is, for example, a mercury lamp, and the exposure light is light of a mixed wavelength including a wavelength range of i-rays to g-rays. The pattern 35 for transfer is transferred to the object to be transferred by exposure light, and a resist pattern is formed by development.

The metal film is patterned by etching using the resist pattern as a photomask. After that, the resist is peeled off. Etching may be performed by wet etching or dry etching.

In addition, the exposure method using the mask 10 of the present invention can also be applied to projection exposure in which an imaging optical system is arranged between the transferee and the mask 10, or dozens of tens of miles are arranged between the transferee and the mask 10. Any of close proximity exposures with a gap of several hundred microns. The photomask 10 can be used in any photolithography process such as the manufacture of semiconductor circuits in addition to flat panel display devices. As a projection exposure device in the case of manufacturing a flat panel display device, an optical system having a NA (Numerical Aperture, numerical aperture) of about 0.08 to about 0.15 can be preferably used.

The electrostatic damage of the photomask 10 and its prevention measures will be described. When manufacturing the mask 10 or operating the mask 10 during the use of the mask 10, electric charges may be injected from the vicinity of the outer edge of the mask 10 due to the contact of the contacting parts or fixtures. For example, a storage box or a carrying device is charged with static electricity, which causes the optical film (light-shielding film 23) of the photomask 10 to be charged.

Generally, when a potential difference occurs between close but discontinuous conductors, there is a case where a discharge occurs in the air. Therefore, there is a concern that static electricity is generated in or near the discharge generating portion 35 of the transfer pattern 35 of the photomask 10, and this electrostatic damage may cause the light-shielding film 23 to break, or foreign matter generated by the break to adhere to The transfer pattern 35 is abnormal. In general, a discharge occurs at the positions where the light-shielding films 23 that cause a potential difference are closest to each other.

When the abnormality occurs in the transfer pattern 35, the pattern having the abnormality is also transferred to the object to be transferred. When such abnormalities occur in the peripheral area 31, the mark pattern is destroyed, and the detection of the position information of the mask 10 becomes difficult. In either case, electronic components such as TFT substrates cannot be manufactured accurately.

According to the electric field simulation performed by the present inventors, if the interval between the isolated patterns including the light-shielding film 23 is 1 mm or more, even if a potential difference of about 1 kV occurs, the discharge in the air can be substantially prevented.

As described above, the light-transmitting annular portion 33 has a width of 1 mm or more. Thereby, the outer peripheral region 31 and the light shielding annular portion 34 are electrically separated. The width of the light-transmitting annular portion 33 is fixed. By eliminating the light-shielding film 23 and the transparent conductive film 25 in the outer peripheral area 31 and the light-shielding film 23 of the light-shielding annular portion 34 locally, even if there is a large difference between them, In the case of a potential difference, it is difficult to generate a discharge.

The transfer pattern 35 is surrounded by the electrically conductive light-shielding annular portion 34, so it is difficult to generate charge injection into the transfer pattern 35, thereby suppressing the light-shielding film 23 in this area and the light-shielding film 23 in the peripheral area 31. Between discharges. Furthermore, even if an electric charge is accidentally injected into the light-shielding film 23 of the transfer pattern 35, the electric charge is diffused to the light-shielding film 23 of the light-shielding annular portion 34 and the potential difference is reduced because the electric conduction is conducted to the light-shielding annular portion 34. Therefore, the possibility of discharge in the transfer pattern 35 can also be reduced.

Since the outer peripheral region 31 is provided with a transparent conductive film 25 having conductivity, as shown in FIG. 2, the alignment mark 32 is surrounded by a light transmitting portion as a pattern design, and even when an isolated portion is included, it is electrically conductive. Not isolated. Therefore, charges are not stored in the isolated portion that is designed as a pattern, and a potential difference is not generated in the peripheral region 31. Therefore, it is possible to prevent discharge in the peripheral region 31.

As described above, by providing the light-transmitting annular portion 33 and the light-shielding annular portion 34, it is possible to reduce the possibility of occurrence of an instantaneous discharge. Therefore, it is possible to reduce the possibility of electrostatic damage to any of the transfer pattern 35 and the alignment mark 32.

In the transfer pattern 35, since the transparent conductive film 25 is not formed in the light transmitting portion, the transmittance of the exposed light is not reduced, and the contrast of the transferred pattern can be favorably maintained. In addition, it does not cause problems caused by the uneven thickness of the transparent conductive film 25 and is not affected by the transmittance and wavelength dependence caused by the film material. Therefore, even if an exposure light source including a specific wavelength region is used In this case, it is preferable that there is no change in the transfer conditions.

4 to 10 are explanatory diagrams illustrating the manufacturing steps of the photomask 10. 4 to 10 each show the same cross section as FIG. 3.

A photomask base 15 in a state where a transparent conductive film 25 is formed near the outer edge on the main surface of the transparent substrate 21 shown in FIG. 4 is shown in FIG. 5. The photomask base 15 has a transfer area 36 for forming a transfer pattern on the inside of the outer peripheral area 31 covered by the transparent conductive film 25. In the transfer area 36, the transparent substrate 21 is exposed.

When the photomask base 15 is prepared, the transparent conductive film 25 can be formed by a film forming method such as sputtering while the central portion of the transparent substrate 21 is covered. When the transparent conductive film 25 is accompanied by an anti-reflection film on the transparent substrate 21 side, the two films are sequentially laminated. In FIGS. 4 to 19, a case where an antireflection film is not provided is shown as an example.

Alternatively, after forming the transparent conductive film 25 or the laminated film of the anti-reflection film and the transparent conductive film 25 on the entire main surface of the transparent substrate 21, the center of the pattern 35 for transfer is formed by lithography. The membrane is removed. Thereby, the mask base 15 having the transparent conductive film 25 formed on the outer peripheral area 31 is completed.

A light-shielding film 23 is further formed on the main surface of FIG. 5. This state is shown in FIG. 6. The light shielding film 23 is also formed by a film forming method such as sputtering. The state shown in FIG. 6 is sometimes referred to as a mask base 15.

A state where the resist 24 is coated on one surface of FIG. 6 is shown in FIG. 7. The resist 24 can be applied by, for example, a slit coater or a spin coater. By performing pre-baking after coating, the adhesion between the resist 24 and the light-shielding film 23 can be improved. The state shown in FIG. 7 may be referred to as a mask base 15. In the following description, a case where the resist 24 is a positive type will be described as an example.

The drawing is performed by using a drawing device such as a laser or an electron beam. Drawing is performed on the resist 24 based on the pattern data used to form the specific transfer pattern 35, the light-shielding annular portion 34, the light-transmitting annular portion 33, and the alignment mark 32 in the peripheral region 31. In the following description, a case where a laser drawing device is used is described as an example. As shown in FIG. 8, a photosensitive portion 241 that is irradiated with laser light and a non-photosensitive portion 242 that is not irradiated with laser light are formed on the resist 24.

The resist 24 is developed to obtain a resist pattern 243 shown in FIG. 9.

Using the resist pattern 243 shown in FIG. 9, an etching step for the light-shielding film 23 is performed. That is, the light-shielding film 23 not covered by the resist pattern 243 is removed from the transparent substrate 21. Since the transparent conductive film 25 formed in the peripheral region 31 is resistant to the etchant of the light-shielding film 23 (here, it is an etchant because it is wet-etched), it is not damaged. The state after the etching step is shown in FIG. 10. Thereafter, the resist pattern 243 is peeled. With the above, the photomask 10 described using FIG. 3 is completed.

In addition, after the resist pattern 243 is peeled off, a protective film may be attached to complete the photomask 10. The pellicle is mounted by attaching the pellicle frame holding the pellicle to the light-shielding film 23 in the outer peripheral area 31.

According to the first embodiment, it is possible to provide a photomask 10 that prevents the occurrence of electrostatic breakdown. Since the anti-static film is not provided on the transfer pattern 35, it is possible to provide a photomask 10 capable of transferring a specific pattern with high accuracy without causing attenuation of exposure light.

According to the first embodiment, it is possible to provide a photomask base 15 for a photomask 10 that prevents generation of static electricity.

[Embodiment 2]
The second embodiment relates to a photomask 10 in which the edges of the light-shielding film pattern and the edges of the transparent conductive film pattern are not in the same position in the peripheral region 31 and the edges of the latter are exposed. The description of the parts in common with the first embodiment will be omitted.

Fig. 11 is a schematic sectional view of a photomask 10 according to the second embodiment. In the second embodiment, the transparent conductive film 25 provided in the outer peripheral region 31 extends to the inner side than the boundary between the outer peripheral region 31 and the light-transmitting annular portion 33.

The light-transmitting ring-shaped portion 33 is a double ring having an outer side covered with a transparent conductive film 25 and an inner side exposing the transparent substrate 21. The light-transmitting annular portion 33 has a portion where the transparent substrate 21 is exposed with a fixed width of 1 mm or more. Although not shown, in the case of the front-view mask 10, the inner edge of the transparent conductive film 25 is parallel to the outer edge of the light-shielding annular portion 34.

According to the second embodiment, the width of the outer peripheral region 31 can be specified without being limited to the width of the transparent conductive film 25 previously provided on the mask base 15.

[Embodiment 3]
The third embodiment relates to a photomask 10 in which the width of the transparent conductive film 25 in the peripheral region 31 is smaller than the width of the light-shielding film pattern. The description of the parts in common with the first embodiment will be omitted.

Fig. 12 is a schematic sectional view of a photomask 10 according to the third embodiment. In the third embodiment, the width of the transparent conductive film 25 is smaller than the width of the outer peripheral region 31. Therefore, the outer peripheral area 31 covers the surface of the transparent substrate 21 inside the transparent conductive film 25. Although not shown, in the case of the front-view mask 10, the inner edge of the outer peripheral region 31 is parallel to the outer edge of the light-shielding annular portion 34.

According to the third embodiment, the width of the outer peripheral region 31 can be specified without being limited to the width of the transparent conductive film 25 previously provided on the mask base 15.

Furthermore, instead of the transparent conductive film 25, a film having light transmittance and conductivity may be provided near the alignment mark 32, so that the isolated light-shielding film 23 in the alignment mark 32 and the light-shielding film in the peripheral area 31 23 is on.

[Embodiment 4]
The fourth embodiment relates to a photomask 10 having a two-layer structure in which the transfer pattern 35 and the light-shielding annular portion 34 have a two-layer structure. The description of the parts in common with the first embodiment will be omitted.

Fig. 13 is a schematic sectional view of a photomask 10 according to the fourth embodiment. The light-shielding annular portion 34 and the transfer pattern 35 of the photomask 10 according to the fourth embodiment include a laminated film of the transparent conductive film 25 and the light-shielding film 23.

14 to 18 are explanatory diagrams explaining the manufacturing steps of the photomask 10 according to the fourth embodiment.

FIG. 14 shows a mask base 15 having a transparent conductive film 25 and a light-shielding film 23 on one main surface area layer of the transparent substrate 21. FIG. 15 shows a photoresist-attached photomask substrate in which a light-shielding film 23 of the photomask substrate 15 of FIG. 14 is laminated with a resist 24. In addition, the resist-attached photomask substrate shown in FIG. 15 may be referred to as a photomask substrate 15.

After the drawing step, a resist pattern 243 is formed by a development step, and a state where the light-shielding film 23 is patterned by the first etching step using the resist pattern 243 is shown in FIG. 16. The transparent conductive film 25 is resistant to the etchant of the light-shielding film 23.

Next, a state where the resist pattern 243 is formed only in the outer peripheral region 31 by the method described below is shown in FIG. 17.

The resist pattern 243 shown in FIG. 16 is peeled off, and a new resist 24 is applied to the entire surface by a method such as a slit coater, and then exposed and developed, leaving only the resist corresponding to the peripheral region 31. The resist portion can thereby form the resist pattern 243 shown in FIG. 17.

The state after the transparent conductive film 25 is etched using the resist pattern 243 is shown in FIG. 18. The transparent conductive film 25 remains in the light-transmitting portion of the transfer pattern 35 except for that.

According to the fourth embodiment, the width of the transparent conductive film 25 is not specified at the stage of the mask base 15. Therefore, the mask manufacturer can arbitrarily determine the width of the transparent conductive film 25.

Compared with the first embodiment, the fourth embodiment is advantageous in that the formation of the mask base 15 is simple. In the transfer pattern 35, there is no problem even if the transparent conductive film 25 exists on the transparent substrate 21 side of the light-shielding film pattern. However, when the transfer pattern 35 includes not only a light-shielding film pattern but also a translucent film (including a phase shift film) pattern, the transfer pattern 35 is not provided with another film on the transparent substrate 21 side. The mask 10 of the aspect 1 is advantageous.

[Embodiment 5]
The fifth embodiment relates to a photomask 10 in which a transparent conductive film 25 and a light shielding film 23 are laminated in the outer region 31 in the reverse order. The description of the parts in common with the first embodiment will be omitted.

Fig. 19 is a schematic sectional view of a mask 10 according to the fifth embodiment. In the peripheral region 31, the light-shielding film pattern forming the mark pattern is covered by the transparent conductive film 25. The manufacturing method of the mask 10 according to the fifth embodiment is as follows. The light-shielding film 23 formed on one main surface of the transparent substrate 21 is patterned into a specific shape by a photolithography method, and a pattern 35 for transferring, a peripheral region 31 having an alignment mark 32, and a pattern for transferring are produced. A mask intermediate body of the transparent ring-shaped portion 33 of the transparent substrate 21 with a specific width is exposed between 35 and the peripheral region 31. Then, a transparent conductive film 25 is laminated on the light shielding film 23 in the peripheral region 31 and the light transmitting portion of the alignment mark 32.

When the transparent conductive film 25 is laminated, the transparent conductive film 25 may be formed in a state in which a region other than the peripheral region 31 is masked. For the above-mentioned photomask intermediate body, after the transparent conductive film 25 is formed on the main surface thereof, a portion other than the peripheral area 31 may be removed by a photolithography step.

According to the fifth embodiment, an ordinary photomask having a pattern 35 for transfer on one of the main surface areas of the transparent substrate 21 can be used, and a photomask 10 can be produced to prevent generation of static electricity.

The technical features (constitutive elements) described in the above embodiments can be combined with each other, and new technical features can be formed by combining them.
It should be considered that the implementation form disclosed this time is an example in all aspects and is not restrictive. The scope of the present invention is indicated by the scope of the patent application rather than the embodiments described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of the patent application.

10‧‧‧Mask

15‧‧‧Mask base

21‧‧‧ transparent substrate

23‧‧‧Light-shielding film

24‧‧‧resist

25‧‧‧ transparent conductive film

31‧‧‧ peripheral area

32‧‧‧Alignment mark

33‧‧‧Transparent ring

34‧‧‧ shade ring

35‧‧‧ transfer pattern

36‧‧‧ transfer area

241‧‧‧Photosensitive Department

242‧‧‧ Non-photosensitive section

243‧‧‧ Resist Pattern

FIG. 1 is a schematic front view of a mask according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged view of a portion A of the photomask shown in FIG. 1. FIG.

FIG. 3 is a schematic sectional view of the photomask taken along the line III-III in FIG. 1.

Fig. 4 is an explanatory diagram for explaining the manufacturing steps of the photomask of the first embodiment.

FIG. 5 is an explanatory diagram illustrating manufacturing steps of the photomask following FIG. 4.

FIG. 6 is an explanatory diagram illustrating manufacturing steps of the photomask following FIG. 5.

FIG. 7 is an explanatory diagram illustrating manufacturing steps of the photomask following FIG. 6.

FIG. 8 is an explanatory diagram illustrating manufacturing steps of the photomask subsequent to FIG. 7.

FIG. 9 is an explanatory diagram illustrating manufacturing steps of the photomask subsequent to FIG. 8.

FIG. 10 is an explanatory diagram illustrating manufacturing steps of the photomask following FIG. 9.

Fig. 11 is a schematic cross-sectional view of a photomask of the second embodiment.

Fig. 12 is a schematic cross-sectional view of a photomask of the third embodiment.

Fig. 13 is a schematic cross-sectional view of a photomask of the fourth embodiment.

FIG. 14 is an explanatory diagram for explaining a manufacturing process of the photomask of the fourth embodiment.

FIG. 15 is an explanatory diagram illustrating manufacturing steps of the photomask following FIG. 14.

FIG. 16 is an explanatory diagram illustrating manufacturing steps of the photomask subsequent to FIG. 15.

FIG. 17 is an explanatory diagram illustrating manufacturing steps of the photomask subsequent to FIG. 16.

FIG. 18 is an explanatory diagram illustrating manufacturing steps of the photomask subsequent to FIG. 17.

Fig. 19 is a schematic cross-sectional view of a mask according to a fifth embodiment.

Claims (14)

A photomask on a main surface of a transparent substrate has: A pattern for transfer, which is formed by patterning an optical film; A light-transmitting annular portion surrounding the outer periphery of the transfer pattern; and An outer peripheral region surrounding the outer periphery of the light transmitting annular portion; and In the outer peripheral region, a transparent conductive film and a marking pattern obtained by patterning the optical film are laminated on the main surface. As claimed in item 1, wherein In the outer peripheral region, the transparent conductive film is formed between the transparent substrate and the optical film. As claimed in item 1, wherein In the outer peripheral region, the optical film is formed between the transparent substrate and the transparent conductive film. As in any one of claims 1 to 3, wherein The optical film includes a light-shielding film. As in any one of claims 1 to 3, wherein The outer edge of the transfer pattern is surrounded by a light-shielding annular portion that is electrically connected to the transfer pattern and forms the optical film on the main surface. As claimed in Item 5, wherein The light-shielding annular portion has an outer edge parallel to the inner edge of the outer peripheral region. As in any one of claims 1 to 3, wherein The light-transmitting annular portion has a part of the surface of the transparent substrate exposed at a width of 1 mm or more throughout the entire circumference. As in any one of claims 1 to 3, wherein The mark pattern is an alignment mark used when the mask is exposed. A photomask base comprising a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding the transfer region on an outer peripheral side of the transfer region, and The transparent substrate is exposed on the transfer region, A transparent conductive film is formed on the transparent substrate in the outer peripheral region. A photomask base comprising a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding the transfer region on an outer peripheral side of the transfer region, and Forming an optical film on the transparent substrate for forming the pattern for the transfer in the transfer region, In the outer peripheral region, a transparent conductive film and the optical film are laminated on the transparent substrate. A method for manufacturing a photomask, which includes: A step of preparing a photomask substrate, the photomask substrate having a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding an outer periphery of the transfer region, and the transfer region is on the transparent substrate. An optical film is formed, and the outer peripheral region is formed by laminating a transparent conductive film and the optical film on the transparent substrate; and A patterning step of patterning only the optical film; and In the patterning step, the transfer pattern is formed, a mark pattern is formed in the outer peripheral region, and a light transmitting portion having the transparent substrate exposed at a specific width is formed between the transfer pattern and the outer peripheral region. Ring section. A manufacturing method of a photomask includes: A step of preparing a photomask substrate, the photomask substrate having a transfer region for forming a transfer pattern on a transparent substrate, and a peripheral region surrounding the outer periphery of the transfer region, and the transfer region and the outer periphery region A laminated film having a transparent conductive film and an optical film formed on the transparent substrate; The patterning step includes forming the transfer pattern in the transfer region by patterning only the optical film, forming a mark pattern in the peripheral region, and forming a pattern between the transfer pattern and the peripheral region. Forming a light-transmitting annular portion having a portion of the transparent substrate exposed at a specific width therebetween; and The removing step is to remove the transparent conductive film exposed in the transfer area through the patterning step. A method for manufacturing a photomask, which includes: A step of preparing a photomask intermediate, which is provided on a transparent substrate with a pattern for transfer, which is formed by patterning an optical film, and a peripheral region, which surrounds the outer periphery of the transfer pattern and has a mark pattern And a light-transmitting ring-shaped portion where a transparent substrate having a specific width is exposed between the transfer pattern and the outer peripheral region; and The step of laminating a transparent conductive film on the outer peripheral area. An electronic component manufacturing method includes the following steps: Prepare a mask as in any of claims 1 to 3; and The above-mentioned transfer pattern is transferred onto a transfer target using an exposure device.