CN115903366A - Photomask and method for manufacturing photomask - Google Patents
Photomask and method for manufacturing photomask Download PDFInfo
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- CN115903366A CN115903366A CN202211206308.2A CN202211206308A CN115903366A CN 115903366 A CN115903366 A CN 115903366A CN 202211206308 A CN202211206308 A CN 202211206308A CN 115903366 A CN115903366 A CN 115903366A
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- light
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/54—Absorbers, e.g. of opaque materials
- G03F1/58—Absorbers, e.g. of opaque materials having two or more different absorber layers, e.g. stacked multilayer absorbers
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F1/00—Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
- G03F1/26—Phase shift masks [PSM]; PSM blanks; Preparation thereof
- G03F1/32—Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion; Preparation thereof
Abstract
The invention provides a photomask and a method for manufacturing the same, wherein the photomask with a semi-transparent pattern can effectively reduce the reflection of exposure light from the photomask in a photoetching step. The photomask of the present invention is provided with a semi-transparent pattern (6 a) formed of a semi-transparent film (6) and a laminated light-shielding pattern (30 a) formed of a laminated light-shielding film (30) of a 1 st reflection suppression film (2), a light-shielding film (3) and a 2 nd reflection suppression film (4) on a transparent substrate (1), wherein the optical density of the semi-transparent film (6) is lower than the optical density of the laminated light-shielding film (30), and the 1 st reflection suppression film (2) is in contact with the transparent substrate 1, and is configured such that the reflectance of the laminated light-shielding pattern (30 a) from the front surface is 15% or less and the reflectance of the laminated light-shielding pattern (30 a) from the back surface is 5% or less with respect to exposure light having a wavelength in the range of 365nm to 436 nm.
Description
Technical Field
The present invention relates to a photomask (photomask) and a method for manufacturing the photomask.
Background
The photomask is used in a step of manufacturing an electronic device such as a flat panel display. Conventionally, a binary (binary) mask having a transmission portion and a light shielding portion has been used as a photomask.
In recent years, for example, a phase shift mask (phase shift mask) having a light-shielding film and a phase shift film is used for forming a fine pattern, and a halftone mask (halftone mask) having a semi-light-transmitting region is used for reducing the number of manufacturing steps of an electronic device.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open No. 2020-64304
Disclosure of Invention
Problems to be solved by the invention
With the development of further uses of flat panel displays and the refinement of required specifications, with respect to such photomasks, the requirement for uniformity of pattern size becomes increasingly strict.
One of the causes of the pattern size unevenness is deterioration of the exposure transfer quality due to stray light generated by reflection of the exposure light from the photomask (patent document 1).
However, it is difficult to prevent or reduce reflection of exposure light from a photomask in a phase shift mask and a halftone mask having a semi-transparent film, and there is a problem that an effect of reducing reflection of exposure light from a back surface cannot be sufficiently obtained.
The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a photomask having a semi-transmissive pattern, which can effectively reduce reflection of exposure light from the photomask in a photolithography step.
Means for solving the problems
The photomask of the present invention is characterized in that:
a translucent pattern and a laminated light-shielding pattern are provided on a transparent substrate,
the semi-light-transmitting pattern is composed of a semi-light-transmitting film,
the laminated light-shielding pattern is composed of a 1 st reflection suppressing film, a light-shielding film, and a 2 nd reflection suppressing film,
the semi-light transmitting film has an optical density lower than that of the laminated light-shielding film,
the 1 st reflection suppression film is in contact with the transparent substrate,
when the surface having the semi-transmissive pattern and the laminated light-shielding pattern is a front surface and the side opposite to the front surface is a back surface of the transparent substrate,
a reflectance of a region where the semi-transmissive pattern overlaps with the laminated light-shielding pattern in the front surface is 15% or less and a reflectance of the laminated light-shielding pattern from the back surface is 5% or less with respect to exposure light having a wavelength in a range of 365nm to 436 nm.
In the photomask of the present invention, the wavelength dependence of the reflectance of the laminated light-shielding pattern from the back surface is within 5%.
With the photomask having such a structure, reflection from the photomask is prevented or reduced, and thus, stray light caused by reflection of exposure light can be prevented.
In particular, the translucent pattern can be provided to effectively prevent or reduce reflection from the translucent back surface.
In the photomask of the present invention, at least a part of the laminated light-shielding pattern is covered with the semi-transparent film.
With the photomask having such a structure, the reflectance of the back surface of the photomask can be effectively reduced without being affected by the semi-transparent film constituting the semi-transparent pattern.
Further, in the photomask of the present invention, the semi-transmissive film is a halftone film or a phase shift film.
The photomask according to the present invention contributes to reduction in the number of manufacturing steps and improvement in the fineness and accuracy of the pattern.
The method for manufacturing a photomask of the present invention includes:
forming a 1 st reflection suppressing film in contact with the transparent substrate;
a step of forming a light-shielding film on the 1 st reflection suppressing film;
a step of forming a 2 nd reflection suppressing film on the light shielding film;
patterning a laminated light-shielding film composed of the 1 st reflection suppressing film, the light-shielding film, and the 2 nd reflection suppressing film to form a laminated light-shielding pattern, and partially exposing the transparent substrate;
a step of forming a semi-light transmissive film on the partially exposed transparent substrate and the laminated light-shielding pattern; and
a step of patterning the semi-light-transmitting film to form a semi-light-transmitting pattern,
the semi-light transmitting film has an optical density lower than that of the laminated light-shielding film,
in the case where the transparent substrate has a surface having the semi-transmissive pattern and the laminated light-shielding pattern as a front surface and a side opposite to the front surface as a rear surface,
a reflectance of a region where the semi-transmissive pattern overlaps with the laminated light-shielding pattern in the front surface is 15% or less and a reflectance of the laminated light-shielding pattern from the back surface is 5% or less with respect to exposure light having a wavelength in a range of 365nm to 436 nm.
By using such a method for manufacturing a photomask, a photomask capable of effectively reducing reflection of exposure light from the photomask can be manufactured.
Effects of the invention
According to the present invention, it is possible to provide a photomask having a semi-transmissive pattern capable of effectively reducing reflection of exposure light from the photomask in a photolithography step.
Drawings
Fig. 1 is a partial sectional view showing a main manufacturing process of a photomask 100 (embodiment 1).
Fig. 2 is a partial sectional view showing a main manufacturing process of the photomask 100 (embodiment 1).
Fig. 3 is a sectional view schematically showing a state where the exposure object 20 is exposed by using the photomask 100 (embodiment 1).
Fig. 4 is a sectional view showing a step of forming the semi-transmissive pattern 6a capable of reducing the front surface reflectance of the photomask 100 (embodiment 1).
Fig. 5 is a sectional view showing a main manufacturing process of the photomask 100 (embodiment 2).
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following embodiments are not intended to be interpreted as limiting the gist of the present invention. Note that the same or similar components may be given the same reference numerals and their description may be omitted.
(embodiment mode 1)
Fig. 1 and 2 are sectional views showing main steps of manufacturing a photomask 100.
The cross-sectional views shown in fig. 1 and 2 are partially enlarged views schematically showing the respective manufacturing steps. Hereinafter, the same applies to other cross-sectional views.
As shown in fig. 1 (a), a 1 st reflection suppression film 2 is formed on a transparent substrate 1 made of a material substantially transparent to exposure light, such as quartz glass, by a vapor deposition method, a sputtering method, or the like.
Then, a light-shielding film 3 made of a material substantially opaque to exposure light is formed on the 1 st reflection suppression film 2 by a vapor deposition method, a sputtering method, or the like.
Next, the 2 nd reflection suppressing film 4 is formed on the light shielding film 3 by a vapor deposition method, a sputtering method, or the like.
As the exposure light used in the photolithography step in the manufacturing process of the electronic device using the photomask 100, for example, i-line (wavelength λ =365 nm), h-line (wavelength λ =405 nm), g-line (wavelength λ =436 nm), or a mixed light including at least 2 of these lights can be used.
The transmittance of the transparent substrate 1 to the wavelength of the exposure light (365 nm. Ltoreq. Lambda. Ltoreq.436 nm) is 90 to 97% (90%. Ltoreq. Transmittance. Ltoreq.97%).
The reflectance (back surface reflectance) of the 1 st reflection suppression film 2 from the transparent substrate 1 side with respect to the wavelength of the exposure light is 5% or less, and the wavelength dependence of the back surface reflectance is within 5%.
The light-shielding film 3 has an optical density (OD value) of 3 or more with respect to the wavelength of the exposure light.
The reflectance (front surface reflectance) of the 2 nd reflection suppression film 4 with respect to the wavelength included in the exposure light is 5% or less.
The light-shielding film 3 is made of a metal film, and is preferably made of a Cr (chromium) film, for example.
The 1 st reflection suppression film 2 and the 2 nd reflection suppression film 4 are preferably a Cr oxide film, a Cr nitride film, a Cr oxynitride film, or a 2-layer or more laminated film composed of any combination of these films. When selective etching is performed with the semi-light-transmitting film 6 described later, ni (nickel) or MoSi (molybdenum silicide) may be used as a material of the reflection suppressing films.
Further, a structure in which the light-shielding film 30 composed of the 1 st reflection suppression film 2, the light-shielding film 3, and the 2 nd reflection suppression film 4 is laminated on the transparent substrate 1 may be prepared in advance as the photomask blank 10.
The laminated light-shielding film 30 has a laminated structure of a 1 st reflection suppression layer composed of a 1 st reflection suppression film 2, a light-shielding layer composed of a light-shielding film 3, and a 2 nd reflection suppression layer composed of a 2 nd reflection suppression film 4, and has an optical density of 5 or more.
As shown in fig. 1B, a resist film 5 (1 st resist film) is formed on the 2 nd reflection suppressing film 4 by a coating method or the like.
Then, as shown in fig. 1 (C), the resist film 5 is patterned by photolithography to form a resist pattern 5a.
In this step, exposure light is irradiated from above (B) of fig. 1 by an exposure device or a laser drawing device. The 2 nd reflection suppressing film 4 can prevent scattering (halation) of exposure light from the light shielding film 3, which causes variation in pattern size.
Then, as shown in fig. 1D, the 1 st reflection suppression film 2, the light shielding film 3, and the 2 nd reflection suppression film 4 are laminated (the light shielding film 30 is laminated) and patterned by etching using the resist pattern 5a as a mask. A laminated light-shielding pattern 30a formed of a laminated film of the 1 st reflection suppressing pattern 2a, the light-shielding pattern 3a, and the 2 nd reflection suppressing pattern 4a is formed. The transparent substrate 1 is partially exposed in the region not covered by the resist pattern 5a.
After that, the resist pattern 5a is removed.
As an etching method for the stacked light-shielding film 30, dry etching can be used. In the case of patterning a mask having a large area, wet etching is suitably used.
The pattern shape of the photoresist pattern 5a may be a wiring pattern shape, a hole pattern shape, or another pattern shape.
Next, as shown in fig. 2 (a), the semi-light-transmissive film 6 is formed by an evaporation method, a sputtering method, or the like. The semi-light transmissive film 6 is formed on the laminated light shielding pattern 30a and the partially exposed transparent substrate 1.
The semi-transparent film 6 is a functional film having semi-transparency and made of a known material such as a Cr-based metal compound, a Si-based compound, or a metal silicide, and functions as a phase shift film or a halftone film. The semi-light transmitting film 6 has an optical density lower than that of the laminated light shielding film 30. The front reflectance of the semi-transmissive film 6 with respect to the exposure light is 15% or less.
The optical properties of the semi-transparent film 6 as a halftone film and a phase shift film can be realized by adjusting the composition and the film thickness, for example.
For example, when the semi-light transmissive film 6 is used as a halftone film, the transmittance of the semi-light transmissive film 6 is set to 10 to 70% (10% to 70% transmittance) with respect to the exposure light wavelength. The phase shift amount is set to be small (approximately 0 DEG, for example, 0 to 20 deg.). As the semi-transparent film 6, for example, a Cr-based metal compound can be used, and preferably, a Cr oxide, a Cr nitride or a Cr oxynitride is formed to have a film thickness of, for example, 5[ nm ] to 20[ nm ].
Further, as a halftone film, it is known that 1 exposure using a photomask 100 makes it possible to provide irradiation regions with different exposure amounts for an exposure object and to form regions with different film thicknesses for a photosensitive material such as a resist formed on the exposure object. As a result, it contributes to reduction of the number of manufacturing steps and the like.
For example, when the semi-transmissive film 6 is used as a phase shift film, the transmittance of the semi-transmissive film 6 is set to 3 to 15% (3% or more and 15% or less), the phase shift amount is set to about 180 ° (160 ° or more and 200 ° or less), and more preferably 170 ° or more and 190 ° or less, with respect to the wavelength of the exposure light. As the semi-transparent film 6, for example, a Cr-based metal compound can be used, and preferably, cr oxide, cr nitride or Cr oxynitride is formed in a film thickness of, for example, 50[ 2 ] nm to 100[ 2 ] nm.
Further, as is well known, a phase shift film shifts the phase of exposure light, and makes it possible to perform fine patterning by utilizing the interference effect of light.
The semi-light-transmitting film 6 has optical characteristics set according to the use. Therefore, the setting can be appropriately made in accordance with the specification required by the customer.
By preparing a photomask blank 10 having a light-shielding film 30 laminated on a transparent substrate 1 in advance and forming a semi-light-transmitting film 6 having suitable optical characteristics on the photomask blank 10 in accordance with the specification of the photomask 100, the production period of various photomasks 100 can be shortened.
Then, as shown in fig. 2B, a resist film 7 (2 nd resist film) is formed on the semi-light-transmitting film 6 by a coating method or the like.
Next, as shown in fig. 2 (C), the resist film 7 is patterned by photolithography to form a resist pattern 7a.
Then, as shown in fig. 2 (D), the semi-transmissive film 6 is selectively etched and patterned using the resist pattern 7a as a mask, thereby forming a semi-transmissive pattern 6a.
After that, the resist pattern 7a is removed.
Among them, dry etching may be used as the etching method of the semi-light transmissive film 6, but wet etching having high selectivity and causing little damage to the lower layer portion of the semi-light transmissive film 6 is suitably used.
Through the above steps, the photomask 100 is formed with: a light-shielding region a in which light-shielding patterns 30a are laminated, a transparent region B in which the transparent substrate 1 is exposed, and a semi-light-transmitting region C in which only a semi-light-transmitting pattern 6a is formed on the transparent substrate 1 are formed on the transparent substrate 1 (fig. 2 (D)).
In the light-shielding region a, the laminated light-shielding pattern 30a and the semi-light-transmitting pattern 6a are overlapped in this order, and the front reflectance of the region where these patterns are overlapped is 15% or less.
Fig. 3 is a sectional view schematically showing a state in which an exposure object, not shown, is exposed by using the photomask 100. In fig. 3, a light source of an exposure apparatus, not shown, is located above the drawing plane, and an exposure object is located below the drawing plane. The exposure light L is irradiated from the back side of the photomask 100, that is, from the side of the transparent substrate 1 where the laminated light-shielding pattern 30a is not formed.
In this method, a photosensitive material such as a resist is formed on the surface of an object to be exposed.
As shown in fig. 3, exposure light L is irradiated from above (back side) in the drawing by an exposure apparatus. When the exposure object is irradiated with exposure light L through the photomask 100, the photosensitive material on the surface of the exposure object is exposed.
When exposure light is irradiated from the transparent substrate 1 side using the photomask 100, exposure unevenness may occur on the exposure apparatus side due to multiple reflections of the exposure light with the optical member by being reflected by the back surface of the light shielding film 3. However, by providing the 1 st reflection suppressing film 2 having a low reflectance between the light shielding film 3 and the transparent substrate 1, reflection of exposure light to the exposure device side can be prevented or reduced.
The 2 nd reflection suppressing film 4 formed on the upper layer of the laminated light shielding film 30 has an effect of preventing or reducing the reflection of the light reflected from the object to be exposed to the object side again.
However, as shown in fig. 2 (D), the laminated light-shielding pattern 30a is covered with the semi-transparent film 6, and the front surface reflectance of the laminated light-shielding pattern 30a may be higher than the back surface reflectance.
As described above, the 1 st reflection suppressing film 2 formed below the stacked light shielding film 30 has an effect of preventing or reducing the exposure light L from being reflected to the exposure device side. As a result, it is possible to prevent or reduce the pattern size variation (or unevenness) of the photosensitive material of the exposure object caused by the stray light generated by the back surface reflection of the exposure light L.
In particular, in the photomask 100, the 1 st reflection suppressing film 2 is provided directly above the transparent substrate 1 and directly contacts the transparent substrate 1, and the semi-light transmitting film 6 is formed above the laminated light shielding film 30. Therefore, the effect of suppressing the back surface reflection by the 1 st reflection suppressing film 2 is not affected by the semi-transparent film 6, and the effect of preventing the reflection of the exposure light L can be sufficiently exhibited.
The light reflected from the object to be exposed may be reflected by the object itself on the object to be exposed using an antireflection film or by providing a photosensitive material such as a photoresist with an antireflection function, and for example, BARC (bottom antireflection coating) or the like may be used.
However, the effect of suppressing reflection by the 1 st reflection suppressing film 2 is important in the countermeasures against back surface reflection of the photomask 100, and the configuration of the photomask 100 in which the 1 st reflection suppressing film 2 is formed directly on the transparent substrate 1 and the semi-transmissive film 6 is formed above the laminated light-shielding film 30 is particularly effective against exposure unevenness.
In addition, when the photomask 100 has the semi-transmissive region C in which the semi-transmissive film 6 is formed, the intensity of the exposure light transmitted through the semi-transmissive region C is reduced.
Therefore, it is preferable that the photomask 100 suppresses reflection of the exposure light to the exposure device side, and the photomask 100 has a back surface reflectance of 5% or less and a front surface reflectance of 15% or less.
In addition, in a display device such as a flat panel display, particularly a large-sized display device, since a mixed light including an i-line, an h-line, and a g-line is used as the exposure light, it is preferable that the wavelength dependency of the back surface reflectance is within 5% in a range of the exposure light wavelength from 365nm to 436 nm.
By forming the light-shielding film 30 in a laminated manner, the value of the optical density OD in the light-shielding region a is increased to 5 or more, and the contrast between the light-shielding region a and the semi-light-transmitting region C is increased. As a result, the function of the semi-light-transmitting film 6 can be improved.
As shown in fig. 2 (D), the laminated light-shielding pattern 30a is covered with the semi-transmissive film 6, and the front reflectance of the laminated light-shielding pattern 30a is not determined by the 2 nd reflection suppressing film 4 but is affected by the front reflectance of the semi-transmissive film 6. When the front reflectance of the semi-light-transmitting film 6 is higher than the front reflectance of the 2 nd reflection suppressing film 4, the front reflectance of the laminated light-shielding pattern 30a tends to be high.
Fig. 4 is a cross-sectional view showing a main step of forming the semi-transmissive pattern 6a capable of reducing the front surface reflectance of the laminated light-shielding pattern 30a of the photomask 100.
The front surface of the photomask 100 is opposite to the back surface, and the transparent substrate 1 is formed with the laminated light-shielding pattern 30a. When exposure is performed using the photomask 100, the side is opposite to the exposure object.
As shown in fig. 4 (a), after the step of fig. 2 (B), the resist film 7 is patterned by photolithography to form a resist pattern 7a, in the same manner as the step of fig. 2 (C).
The photoresist pattern 7a is used as an etching mask for patterning the semi-transparent film 6.
In this step, the resist pattern 7a and the laminated light-shielding pattern 30a have an overlapping region D in consideration of an overlapping error (alignment error) of a drawing device (or an exposure device) that exposes the resist film 7. That is, when the light-shielding region a and the semi-transmissive region C are adjacent to each other, the resist pattern 7a is configured to form the overlap region D at the boundary between the light-shielding region a and the semi-transmissive region C.
The overlap width W of the overlap region D can be set to a value corresponding to the alignment error.
Then, as shown in fig. 4 (B), the semi-light transmissive film 6 is selectively etched with respect to the laminated light-shielding pattern 30a using the resist pattern 7a as a mask, thereby forming a semi-light transmissive pattern 6a. As the etching method of the semi-light transmissive film 6, wet etching can be suitably employed.
After that, the resist pattern 7a is removed, and the photomask 100 can be obtained.
In order to selectively etch the semi-light-transmitting film 6, a material different from the laminated light-shielding film 30 is used for the semi-light-transmitting film 6. For example, ni or MoSi is used as the material of the semi-light-transmitting film 6, cr is used as the material of the laminated light-shielding film 30, or Cr is used as the material of the semi-light-transmitting film 6, and Ni or MoSi is used as the material of the laminated light-shielding film 30.
The semi-transmissive pattern 6a is partially formed (overlapped) on the laminated light-shielding pattern 30a in the overlap region D. Therefore, the 2 nd reflection suppressing pattern 4a is partially covered with the semi-transmissive pattern 6a in the overlap region D, and is exposed in the other region. A low reflectance can be secured on the surface of the laminated light-shielding pattern 30a not covered with the semi-transmissive pattern 6a.
When the reflectance of the semi-light transmitting film 6 is larger than the reflectance of the 2 nd reflection suppressing film 4, the reflectance of the entire surface of the laminated light shielding pattern 30a can be substantially reduced by reducing the area occupied by the semi-light transmitting film 6 on the laminated light shielding pattern 30a to increase the exposed area of the 2 nd reflection suppressing film 4.
As a result, the front reflectance of the entire photomask 100 is also reduced, and multiple reflections with the exposure object can be reduced in the photolithography step using the photomask 100, which can contribute to further preventing or reducing exposure unevenness.
(embodiment mode 2)
A method for patterning the semi-transmissive pattern 6a will be described below, which can reduce an overlay error between the laminated light-shielding pattern 30a in the light-shielding region a and the resist pattern 7a used for patterning the semi-transmissive pattern 6a.
Fig. 5 is a sectional view showing a main manufacturing step of the photomask 100.
As shown in fig. 5 (a), after the step shown in fig. 1 (D), the semi-light-transmissive film 6 is formed by a vapor deposition method, a sputtering method, or the like, in the same manner as the step shown in fig. 2 (a).
Then, as shown in fig. 5 (B), a resist film 7 is formed on the semi-transmissive film 6 by an application method or the like.
Next, as shown in fig. 5 (C), the resist film 7 is patterned by photolithography to form a resist pattern 7a.
Then, as shown in fig. 5 (D), the semi-transmissive film 6 is etched and patterned using the resist pattern 7a as a mask to form a semi-transmissive pattern 6a.
Further, the laminated light-shielding pattern 30a composed of the 1 st reflection suppressing pattern 2a, the light-shielding pattern 3a, and the 2 nd reflection suppressing pattern 4a is etched using the photoresist pattern 7a as a mask to form a laminated light-shielding pattern 30b composed of the 1 st reflection suppressing pattern 2b, the light-shielding pattern 3b, and the 2 nd reflection suppressing pattern 4 b.
Among them, wet etching can be suitably used as the etching method.
In this embodiment, the semi-transmissive film 6 and the laminated light-shielding pattern 30a may be etched simultaneously using the resist pattern 7a as a mask to form the semi-transmissive pattern 6a and the laminated light-shielding pattern 30b.
The light-shielding laminated film 6 may be selectively etched with respect to the light-shielding laminated film 6a using the photoresist pattern 7a as a mask, and then the light-shielding laminated film 30a may be selectively etched with respect to the light-shielding laminated film 6 using the photoresist pattern 7a as a mask to form the light-shielding laminated pattern 30b.
In this way, the laminated light-shielding pattern 30b can be formed by performing patterning on the laminated light-shielding film 30 2 times.
After that, the resist pattern 7a is removed. The photomask 100 can be obtained.
Through the above steps, the photomask 100 is formed with: a light-shielding region a in which light-shielding patterns are laminated, a transparent region B in which the transparent substrate 1 is exposed, and a semi-light-transmitting region C in which only the semi-light-transmitting pattern 6a is formed on the transparent substrate 1 are formed on the transparent substrate 1 (fig. 5 (D)).
Since the semi-light-transmitting film 6 and the laminated light-shielding pattern 30a are etched using the resist pattern 7a as a mask to form the semi-light-transmitting pattern 6a and the laminated light-shielding pattern 30b, the overlay error between the two is reduced, and the miniaturization of the pattern and the burden of pattern design are reduced.
The photomask 100 can prevent back reflection and prevent or reduce exposure unevenness.
Industrial applicability of the invention
According to the present invention, reflection from a pattern on a photomask can be reduced, uneven exposure can be prevented, and the dimensional accuracy of a pattern formed using the photomask can be improved.
The use of the photomask in a production process of a product such as a display device can contribute to improvement in performance of the product, and the like, and is industrially highly applicable.
Description of the reference numerals
1. Transparent substrate
2. 1 st reflection suppressing film
3. Light shielding film
3a light-shielding pattern
4. 2 nd reflection suppressing film
5. Photoresist film (No. 1 photoresist film)
5a resist Pattern (No. 1 resist Pattern)
6. Semi-light-transmitting film
6a semi-transparent pattern
7. Light resistance film (No. 2 light resistance film)
7a resist pattern (No. 2 resist pattern)
10. Photomask blank
30. Laminated light-shielding film
30a laminated light-shielding pattern
100. Photomask and method of manufacturing the same
A light-shielding region
B transparent region
Semi-transparent region of C
D overlap region
W overlap width
L exposure light.
Claims (6)
1. A photomask, comprising:
the transparent substrate has a semi-transparent pattern and a laminated light-shielding pattern,
the semi-light-transmitting pattern is composed of a semi-light-transmitting film,
the laminated light-shielding pattern is composed of a laminated light-shielding film of a 1 st reflection suppressing film, a light-shielding film and a 2 nd reflection suppressing film,
the semi-light transmitting film has an optical density lower than that of the laminated light-shielding film,
the 1 st reflection suppression film is in contact with the transparent substrate,
in the transparent substrate, when a surface having the semi-transmissive pattern and the laminated light-shielding pattern is a front surface and a side opposite to the front surface is a back surface,
a reflectance of a region where the semi-transmissive pattern overlaps with the laminated light-shielding pattern in the front surface is 15% or less and a reflectance of the laminated light-shielding pattern from the back surface is 5% or less with respect to exposure light having a wavelength in a range of 365nm to 436 nm.
2. The photomask of claim 1, wherein:
the wavelength dependence of the reflectance of the laminated light-shielding pattern from the back surface is within 5%.
3. The photomask of claim 1, wherein:
at least a part of the laminated light-shielding pattern is covered with the semi-light-transmitting film.
4. The photomask of claim 2, wherein:
at least a part of the laminated light-shielding pattern is covered with the semi-light-transmitting film.
5. The photomask of any of claims 1 to 4, wherein:
the semi-transparent film is a halftone film or a phase shift film.
6. A method of manufacturing a photomask, comprising:
a step of forming a 1 st reflection suppressing film in contact with the transparent substrate;
a step of forming a light-shielding film on the 1 st reflection suppression film;
a step of forming a 2 nd reflection suppressing film on the light shielding film;
patterning a laminated light-shielding film composed of the 1 st reflection suppressing film, the light-shielding film, and the 2 nd reflection suppressing film to form a laminated light-shielding pattern, and partially exposing the transparent substrate;
a step of forming a semi-light transmissive film on the partially exposed transparent substrate and the laminated light-shielding pattern; and
a step of patterning the semi-transmissive film to form a semi-transmissive pattern,
the semi-light transmitting film has an optical density lower than that of the laminated light-shielding film,
in the case where the transparent substrate has a surface having the semi-transmissive pattern and the laminated light-shielding pattern as a front surface and a side opposite to the front surface as a rear surface,
for exposure light having a wavelength in the range of 365nm to 436nm,
the reflectance of the region of the front surface where the semi-transmissive pattern and the laminated light-shielding pattern overlap is 15% or less, and the reflectance of the laminated light-shielding pattern from the rear surface is 5% or less.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2021160800A JP2023050611A (en) | 2021-09-30 | 2021-09-30 | Photomask and manufacturing method of photomask |
| JP2021-160800 | 2021-09-30 |
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| Publication Number | Publication Date |
|---|---|
| CN115903366A true CN115903366A (en) | 2023-04-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211206308.2A Pending CN115903366A (en) | 2021-09-30 | 2022-09-30 | Photomask and method for manufacturing photomask |
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| Country | Link |
|---|---|
| JP (1) | JP2023050611A (en) |
| KR (1) | KR20230046984A (en) |
| CN (1) | CN115903366A (en) |
| TW (1) | TWI820920B (en) |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1783546B1 (en) * | 2004-06-16 | 2014-03-05 | Hoya Corporation | Semitransmitting film, photomask blank and photomask |
| JP4934237B2 (en) * | 2007-09-29 | 2012-05-16 | Ｈｏｙａ株式会社 | Gray-tone mask manufacturing method, gray-tone mask, and pattern transfer method |
| JP4934236B2 (en) * | 2007-09-29 | 2012-05-16 | Ｈｏｙａ株式会社 | Gray tone mask blank, gray tone mask manufacturing method, gray tone mask, and pattern transfer method |
| TWI457697B (en) * | 2009-01-15 | 2014-10-21 | Shinetsu Chemical Co | Photomask making method, photomask blank and dry etching method |
| KR102002269B1 (en) * | 2010-07-30 | 2019-07-19 | 칼 짜이스 에스엠티 게엠베하 | Euv exposure apparatus |
| JP6127977B2 (en) * | 2011-10-21 | 2017-05-17 | 大日本印刷株式会社 | Large phase shift mask and manufacturing method of large phase shift mask |
| JP6625692B2 (en) * | 2017-07-14 | 2019-12-25 | Hoya株式会社 | Photomask blank and method for manufacturing the same, photomask manufacturing method, and display device manufacturing method |
| US11294286B2 (en) * | 2018-06-27 | 2022-04-05 | Taiwan Semiconductor Manufacturing Co., Ltd. | Pattern formation method using a photo mask for manufacturing a semiconductor device |
| CN112034674A (en) * | 2020-08-25 | 2020-12-04 | 安徽省徽腾智能交通科技有限公司泗县分公司 | Method for preparing phase shift mask |
-
2021
- 2021-09-30 JP JP2021160800A patent/JP2023050611A/en active Pending
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2022
- 2022-09-20 TW TW111135505A patent/TWI820920B/en active
- 2022-09-22 KR KR1020220119957A patent/KR20230046984A/en unknown
- 2022-09-30 CN CN202211206308.2A patent/CN115903366A/en active Pending
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| Publication number | Publication date |
|---|---|
| KR20230046984A (en) | 2023-04-06 |
| TWI820920B (en) | 2023-11-01 |
| JP2023050611A (en) | 2023-04-11 |
| TW202316195A (en) | 2023-04-16 |
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