WO2010041508A1

WO2010041508A1 - Photomask

Info

Publication number: WO2010041508A1
Application number: PCT/JP2009/063672
Authority: WO
Inventors: 康夫原
Original assignee: Jsr株式会社
Priority date: 2008-10-10
Filing date: 2009-07-31
Publication date: 2010-04-15
Also published as: TW201015210A; JP2010113315A

Abstract

Provided is a photomask, which is applicable to patterns having thinner lines on recent printed wiring boards and to severer required accuracy and has convenience equivalent to that in the case where a polyester film is used as a base material, even without using glass as the base material. The photomask is composed of at least the base material composed of a film or a sheet having a polymeric compound as a main component, a light blocking layer arranged at least on one surface of the base material, and a frame arranged at least on one surface of the base material. The photomask has the base material fixed thereto in a state where a tensile force is applied to the frame, in the atmosphere under which the photomask is used and stored.

Description

Photo mask

The present invention relates to a photomask used for manufacturing an electric circuit board such as a semiconductor, a liquid crystal display or a printed wiring board, and etching a metal foil.

Conventionally, photolithography that optically transfers a mask pattern has been widely used in the manufacture of electrical circuit boards such as semiconductors, liquid crystal displays, and printed wiring boards, and etching of metal foils.

The mask used for this photolithography is usually called a photomask or a reticle, and generally comprises an optically transparent base material and a light shielding layer provided on the surface of the base material. Has been. In the present invention, masks used for photolithography called photomasks or reticles are collectively referred to as “photomasks”.

For this optically transparent substrate, a polyester film and a glass such as soda lime glass or quartz glass are appropriately selected and used according to required characteristics.

That is, a polyester film is often used when the line width of the pattern is relatively large and the required accuracy regarding the position and shape is not strict, such as etching processing of a printed wiring board or metal foil.

On the other hand, glass such as soda lime glass or quartz glass was exclusively used when the line width of the pattern was small and the required accuracy regarding the position and shape was severe as in semiconductors and liquid crystal displays.

In recent years, final products equipped with printed wiring boards such as mobile phones and digital cameras are rapidly becoming smaller and thinner. As a result, the mounting density of electronic components such as various semiconductors, resistors, and capacitors has increased. The pattern has become thinner and the required accuracy has become stricter.

For this reason, in the conventional polyester film, the dimensional change is caused by the change of temperature and humidity, and there is a problem that it is not possible to cope with the finer pattern and the required accuracy.

The change in humidity caused by the weather is particularly large compared to the change in temperature, and it greatly affects the accuracy and shape of photomasks using polyester film as a base material. In dealing with this, the biggest problem was suppression of dimensional changes accompanying changes in humidity.

For this reason, there are many cases where glass used exclusively for manufacturing semiconductors and liquid crystal displays is used as a base material for manufacturing printed wiring boards.

However, when glass is used as the base material for the photomask, not only the cost is increased as compared with the polyester film, but also problems such as prevention of breakage, decrease in workability due to increase in weight, and securing of a storage location become problems.

For this reason, in a photomask based on a polyester film that is cheaper than glass, other transparent films are added to the base photomask made of a conventional polyester film in order to reduce dimensional changes accompanying changes in temperature and humidity. Patent Documents 1 and 2 disclose techniques for stacking to reduce dimensional changes.

Japanese Patent Laid-Open No. 2002-72451 JP 2002-169269 A

However, a substrate using a polyester film laminated with a transparent film as described in Patent Document 1 and Patent Document 2 still has a dimensional change accompanying changes in temperature and humidity, compared to a substrate using glass. However, it was still large and could not always cope with the recent demands for finer patterns and stricter required accuracy.

In view of the present situation, the present invention can cope with the recent thinning of the pattern of printed wiring boards and the strictness of required accuracy without using glass as a base material, and uses a polyester film as a base material. An object is to provide a photomask having the same convenience as the case.

The present invention was invented in order to achieve the problems and objects in the prior art as described above,
The photomask of the present invention is
A substrate made of a film or sheet mainly composed of a polymer compound;
A light shielding layer disposed on at least one surface of the substrate;
A frame disposed on at least one surface of the substrate;
A photomask comprised of at least
The photomask is
In an atmosphere where it is used and stored,
The base material is fixed to the frame in a tensioned state.

If the base material is fixed to the frame in a tensioned state in this way, there is almost no dimensional change associated with a change in humidity, and the dimensional change associated with a temperature change can be significantly reduced compared to a conventional photomask. .

For this reason, the photomask of the present invention can be used or stored in the same manner as a photomask using a substrate made of glass in response to the recent demands for thinning the pattern and stricter accuracy requirements. This can be dealt with without special adjustment, and the manufacturing cost can be reduced.

The photomask of the present invention is
The frame is made of a material having a coefficient of thermal expansion of 35 ppm / ° C. or less.

A photomask using a frame made of a material having such a coefficient of thermal expansion has no dimensional change associated with a change in humidity, and the dimensional change associated with a temperature change is smaller than that of a conventional photomask. Therefore, it is possible to cope with the situation without special adjustment of the atmosphere, and the manufacturing cost can be reduced.

The photomask of the present invention is
The substrate is characterized in that the coefficient of thermal expansion is higher than the coefficient of linear expansion of humidity.

Thus, when the thermal linear expansion coefficient of the substrate is larger than the humidity linear expansion coefficient, the frame is necessary to always maintain tension against the dimensional change accompanying the humidity change in the atmosphere used and stored. The fixed temperature can be set widely, and the choice of processing conditions is expanded.

The photomask of the present invention is
The base material has a cyclic olefin resin as a main component.

Such a base material mainly composed of a cyclic olefin resin is suitable because it has high heat resistance and has a wide selection range of fixing temperature, low water absorption and low coefficient of linear expansion of humidity.

According to the present invention, even if glass is not used as a base material, it can cope with the recent thinning of printed wiring board patterns and stricter required accuracy, and is equivalent to the case where a polyester film is used as a base material. A photomask having convenience can be provided.

FIG. 1 is a schematic view of a photomask of the present invention, FIG. 1 (a) is a front view, and FIG. 1 (b) is a cross-sectional view taken along line XX of FIG. 1 (a). FIG. 2 is an explanatory diagram for explaining a pattern formed on the photomask of the present invention. FIG. 2A is a front view of the photomask on which a plurality of patterns are formed, and FIG. It is a front view of the photomask in which one pattern was formed. FIG. 3 is a process diagram for explaining the photomask manufacturing method of the present invention. FIG. 4 is a process diagram for explaining the photomask manufacturing method of the present invention. FIG. 5 is a front view of a photomask on which a score for a change measurement test of a distance between scores is drawn.

Hereinafter, embodiments of the present invention will be described in more detail based on the drawings.

FIG. 1 is a schematic view of a photomask of the present invention, FIG. 1 (a) is a front view, FIG. 1 (b) is a cross-sectional view taken along line XX of FIG. 1 (a), and FIG. It is explanatory drawing for demonstrating the pattern formed in the photomask of invention, Comprising: Fig.2 (a) is a front view of the photomask in which the several pattern was formed, FIG.2 (b) formed one pattern FIGS. 3 and 4 are process diagrams for explaining the photomask manufacturing method of the present invention.

The photomask of the present invention is used for photolithography for optically transferring a photomask pattern in the manufacture of an electric circuit board such as a semiconductor, a liquid crystal display or a printed wiring board, or in the etching of a metal foil.
<Photomask 10>
As shown in FIG. 1A and FIG. 1B, a photomask 10 of the present invention includes a base material 14 made of a film or sheet mainly composed of a polymer compound, and one of the base materials 14. The light shielding layer 16 is disposed on the surface (upper surface side in FIG. 1), and the frame 12 is disposed on the other surface (lower surface side in FIG. 1) of the base material 14.

The photomask 10 of the present invention is characteristic in that the base material 14 is fixed to the frame 12 in a tensioned state in the atmosphere in which it is used and stored.

Here, the shape of the base material 14 and the frame 12 is usually a quadrangle or a rectangle. However, this shape is not particularly limited, and may be, for example, a circle or a polygon. Further, the frame 12 may be provided on both surfaces of the base material 14 in order to increase the mechanical strength of the photomask 10 and suppress deformation such as warpage. In that case, the frame 12 is provided on the light shielding layer 16. It may be provided.

A film or sheet mainly composed of a polymer compound used as the base material 14 of such a photomask 10 needs to be optically transparent.

Here, optically transparent means that the light transmittance at the wavelength of the light source used for photolithography is high, and the light transmittance is 70% or more, preferably 80% or more, more preferably 85% or more. It is.

In addition, the atmosphere in which the above-described photomask 10 is used or stored normally has a temperature range of 20 ° C. to 60 ° C. and a humidity range of 40% RH to 70% RH. Of course, if it is out of this range, the base material 14 needs to be fixed to the frame 12 made of a specific material in a state where tension is applied in the atmosphere.

In the present invention, since the base material 14 needs to be fixed to the frame 12 under tension in an atmosphere where the photomask 10 is used or stored, a polymer compound used as the base material 14 is used. It is preferable that the thermal linear expansion coefficient of the film or sheet as the main component is larger than the humidity linear expansion coefficient.

That is, for example, in order to fix the base material 14 to the frame 12 in a tensioned state at 50 ° C., the temperature at the time of fixing (fixing temperature) is usually set to 50 ° C. or more, and the temperature difference from 50 ° C. This can be achieved by utilizing the shrinkage of the base material 14 (product of temperature difference and coefficient of thermal expansion).

However, in order to maintain the tension applied to the base material 14 even when the humidity changes, the shrinkage of the base material 14 due to the temperature difference between the fixed temperature and 50 ° C. is larger than the shrinkage due to the humidity change. Must.

For this reason, in the photomask 10 of the present invention, it is preferable to use a base material 14 having a thermal linear expansion coefficient larger than the humidity linear expansion coefficient.

If the absolute value of the coefficient of thermal expansion is not greater than the absolute value of the coefficient of linear expansion of humidity, the maximum change in humidity is 100% RH (0% RH to 100% RH). Therefore, the heat resistance temperature of the base material 14 may be exceeded and processing may not be possible.

In the present invention, the thermal linear expansion coefficient is defined as a dimensional change with respect to a temperature of 1 ° C., and the humidity linear expansion coefficient is defined as a dimensional change with respect to a humidity of 1% RH.

Here, as the polymer compound used for the base material 14 of the present invention, for example, an acrylic resin, a polyester resin, a polycarbonate resin, a cyclic olefin resin, or the like can be used.

Among these, the cyclic olefin resin is preferable because of its high heat resistance and a wide selection range of the fixing temperature, low water absorption and low coefficient of linear expansion of humidity.

Specific examples of the cyclic olefin resin include, for example, a cyclic olefin resin, a trade name “ARTON” (manufactured by JSR Corporation), a trade name “ZEONEX” (manufactured by ZEON Corporation), and a trade name “ZEONOR” (ZEON CORPORATION). And a product name “Apel” (Mitsui Chemicals Co., Ltd.), and a polymer compound obtained by using a cyclic olefin compound represented by the following formula (1) as a monomer. Can be mentioned.

[In the formula (1), R ¹ to R ⁴ each independently represent a hydrogen atom; a halogen atom; a substituted or unsubstituted carbon atom which may have a linking group containing oxygen, nitrogen, sulfur or silicon 1 Represents a hydrocarbon group of ˜15 or other monovalent organic group.

Here, R ¹ and R ² or R ³ and R ⁴ may be bonded to each other to form an alkylidene group, and R ¹ and R ² , R ³ and R ^4, or R ² and R ³ may be They may be bonded to each other to form a carbocycle or a heterocycle (these carbocycles or heterocycles may be monocyclic structures, or other rings may be condensed to form a polycyclic structure). .

The formed carbocyclic or heterocyclic ring may be an aromatic ring or a non-aromatic ring. X represents an integer of 0 to 3, and y represents 0 or 1. ]
Specific examples of the cyclic olefin compound represented by the formula (1) include the compounds shown below.

Bicyclo [2.2.1] hept-2-ene,
5-methyl-bicyclo [2.2.1] hept-2-ene,
5-ethyl-bicyclo [2.2.1] hept-2-ene,
5-cyclohexyl-bicyclo [2.2.1] hept-2-ene,
5-phenyl-bicyclo [2.2.1] hept-2-ene,
5- (4-biphenyl) -bicyclo [2.2.1] hept-2-ene,
5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-phenoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-phenoxyethylcarbonyl-bicyclo [2.2.1] hept-2-ene,
5-phenylcarbonyloxy-bicyclo [2.2.1] hept-2-ene,
5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-methyl-5-phenoxycarbonyl-bicyclo [2.2.1] hept-2-ene,
5-methyl-5-phenoxyethylcarbonyl-bicyclo [2.2.1] hept-2-ene,
5-vinyl-bicyclo [2.2.1] hept-2-ene,
5-ethylidene-bicyclo [2.2.1] hept-2-ene,
5,5-dimethyl-bicyclo [2.2.1] hept-2-ene,
5,6-dimethyl-bicyclo [2.2.1] hept-2-ene,
5-fluoro-bicyclo [2.2.1] hept-2-ene,
5-chloro-bicyclo [2.2.1] hept-2-ene,
5-bromo-bicyclo [2.2.1] hept-2-ene,
5,6-difluoro-bicyclo [2.2.1] hept-2-ene,
5,6-dichloro-bicyclo [2.2.1] hept-2-ene,
5,6-dibromo-bicyclo [2.2.1] hept-2-ene,
5-hydroxy-bicyclo [2.2.1] hept-2-ene,
5-hydroxyethyl-bicyclo [2.2.1] hept-2-ene,
5-cyano-bicyclo [2.2.1] hept-2-ene,
5-amino-bicyclo [2.2.1] hept-2-ene,
Tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
Tricyclo [4.4.0.1 ^2,5 ] undec-3-ene,
7-methyl - tricyclo [4.3.0.1 ^{2, 5]} dec-3-ene,
7-ethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-cyclohexyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7-phenyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7- (4-biphenyl) -tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7,8-dimethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,8,9-trimethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
8-methyl-tricyclo [4.4.0.1 ^2,5 ] undec-3-ene,
8-phenyl-tricyclo [4.4.0.1 ^2,5 ] undec-3-ene,
7-fluoro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7-chloro - tricyclo [4.3.0.1 ^{2, 5]} dec-3-ene,
7-bromo-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,8-dichloro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7,8,9-trichloro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-chloromethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7-dichloromethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-trichloromethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7-hydroxy-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
7-cyano-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene,
7-amino-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene;
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodeca-3-ene,
Pentacyclo [7.4.0.1 ^2,5 . 1 ^8,11 . 0 ^7,12] pentadeca-3-ene,
Hexacyclo [8.4.0.1 ^2,5 . 1 ^7,14 . 1 ^9,12 . 0 ^8,13] -heptadec-3-ene,
8-methyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-ethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-cyclohexyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-phenyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-en,
8- (4-biphenyl) -tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-phenoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-phenoxyethylcarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-phenylcarbonyloxy-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-methyl-8-phenoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-methyl-8-phenoxyethylcarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-vinyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8,8-Dimethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8,9-dimethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-Fluoro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-chloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-Bromo-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8,8-Dichloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8,9-Dichloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8,8,9,9-tetrachloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-hydroxy-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-hydroxyethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-methyl-8-hydroxyethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-cyano-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-en,
8-amino-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene.

In addition, these cyclic olefin compounds may be used alone or in combination of two or more. Moreover, you may use together the compound copolymerizable with these monomers.

The kind and amount of the cyclic olefin compound and copolymerizable compound constituting the monomer or monomer composition are appropriately selected depending on the properties required for the obtained cyclic olefin resin.

Among these cyclic olefin-based resins, those having a glass transition temperature (Tg) of 80 ° C. or higher, preferably 100 ° C. or higher, more preferably 120 ° C. or higher have a fixing temperature when fixing the frame 12 and the substrate 14. A water absorption rate of 0.5% or less, preferably 0.3% or less, and more preferably 0.25% or less is preferable because the coefficient of linear thermal expansion is small.

Of course, the cyclic olefin-based resin that can be used in the present invention is not limited to these examples.

The thickness of the film or sheet mainly composed of the polymer compound used as the substrate 14 in the present invention is not particularly limited as long as the above conditions are satisfied, but is usually 0.01 mm to 50 mm, preferably 0.05 mm. It is ˜30 mm, more preferably 0.1 mm to 15 mm.

Here, if the thickness of the base material 14 is less than 0.01 mm, it may be too thin to reduce the strength of the photomask 10 and make it difficult to handle.

On the other hand, if the thickness of the base material 14 exceeds 50 mm, the weight of the photomask 10 increases, which may make handling difficult.

In the present invention, the film or sheet mainly composed of the polymer compound used as the base material 14 is blended with an antioxidant, a coupling agent, an antistatic agent, a flame retardant, a dye, a pigment and the like as long as it is optically transparent. May be.

Further, as long as it is optically transparent, a reinforcing material such as glass fiber, glass cloth or various fillers may be contained.

The method for producing a film or sheet mainly composed of a polymer compound used as the substrate 14 in the present invention is not particularly limited, and known methods such as an injection molding method, a blow molding method, a melt extrusion method, and a solution casting method. It can manufacture by the method of. Further, it may be stretched.

The frame 12 is preferably made of a material having a coefficient of thermal expansion of 35 ppm / ° C. or less, more preferably 30 ppm / ° C. or less, still more preferably 15 ppm / ° C. or less, and most preferably 10 ppm / ° C. or less.

Examples of the material of the frame 12 include glass-based materials such as soda lime glass, Pyrex (registered trademark) glass, and quartz glass, aluminum, silicon, nickel, carbon steel, stainless steel (SUS304, SUS316, SUS410), and iron. Metallic materials such as nickel alloys (42 alloy), ceramics materials such as alumina, aluminum nitride, silicon carbide and silicon nitride, epoxy resins and polyester resins containing fillers such as glass fiber, silica, alumina and boron nitride, Examples thereof include composite resin materials such as polyimide resin and polycarbonate resin. Among these, glass-based materials, ceramic-based materials, and metal-based materials are preferable because they are substantially free from dimensional changes due to humidity, and metal-based materials are more preferable because they are excellent in workability.

The thickness and width of the frame 12 of the photomask 10 in the present invention are not particularly limited as long as they are not deformed by the tension of the film or sheet mainly composed of the polymer compound to be fixed. The width is 100 mm and the width is 5 mm to 150 mm.

In addition, as the light shielding layer 16 used in the present invention, a conventionally known one can be applied, and for example, it can be obtained by coating a silver salt photosensitive emulsion. Furthermore, it is also possible to use a photosensitive ink or paint obtained by blending a pigment or a dye with a photosensitive resin. The thickness of the light shielding layer 16 may be any thickness as long as the light transmittance of the light shielding portion is usually 1% or less, and is usually 2 to 10 μm.

Also, the light shielding layer 16 can be formed by providing a metal thin film by vapor deposition or the like. In this case, chromium or a multilayer film of chromium and chromium oxide is often used, but silicon, iron oxide, molybdenum silicite, or the like can also be used as a film material. In this case, the thickness of the light shielding layer 16 is as follows. Usually 80 to 150 nm.

The light shielding layer 16 is usually provided on one surface of the base material, but does not prevent the light shielding layer 16 from being provided on both surfaces.

Furthermore, in the present invention, a functional layer (not shown) such as a protective layer, an antireflection layer, or an antistatic layer can be provided on the base material 14 or the light shielding layer 16. Such a functional layer may be provided by coating a liquid raw material, or may be provided by bonding a film having these functions.

Further, in the light shielding layer 16, even if a plurality of patterns 20a are formed on one light shielding layer 16 as in the photomask 10a shown in FIG. 2A, the photomask 10b shown in FIG. As described above, one pattern 20 b may be formed on one light shielding layer 16. A plurality of types of patterns may be formed on one light shielding layer 16 and can be appropriately selected.

As described above, in the photomask 10 of the present invention, the base material 14 is fixed in a tensioned state to the frame 12 made of a material having a thermal linear expansion coefficient of 35 ppm / ° C. or less in an atmosphere where it is used and stored. Therefore, there is no dimensional change associated with a humidity change, and the dimensional change associated with a temperature change can be significantly reduced as compared with a conventional photomask.

For this reason, in response to the recent demands for pattern thinning and stricter precision requirements, as with photomasks using glass substrates, it can be used without special adjustment of the atmosphere used or stored. Manufacturing cost can be reduced.
<Method for Manufacturing Photomask 10>
A method for manufacturing the above-described photomask 10 will be described below.

In the method of manufacturing the photomask 10 of the present invention, first, as shown in FIG. 3A, a frame 12 made of a material having a thermal linear expansion coefficient of 35 ppm / ° C. or less is prepared.

Next, as shown in FIG. 3B, an adhesive is applied to one surface of the frame 12 (the upper surface in FIG. 3B).

Further, a base material 14 that is slightly larger than the frame 12 is bonded onto the frame 12 to which the adhesive is applied at room temperature.

Then, after bonding the base material 14 on the frame 12, the adhesive is cured by heating at a temperature higher than the temperature at which the base material 14 is used and stored, usually 100 ° C. or higher, and the base material 14 is fixed to the frame 12. Then, when it cools to the temperature used or stored, the base material 14 will be fixed to the flame | frame 12 in the tensioned state.

Further, as shown in FIG. 3C, the light shielding layer 16 is provided on the surface of the base material 14 where the frame 12 is not adhered (the upper surface in FIG. 3C).

The method of providing the light shielding layer 16 varies depending on the material of the light shielding layer 16. For example, in the case of a silver salt photosensitive emulsion, coating is performed using a known coater such as a roll coater or a slit coater, followed by drying.

On the other hand, in the case of a metal thin film such as a chromium / chromium oxide composite layer, it is provided by vapor deposition. In the case of a metal thin film, a resist layer for etching is usually further provided thereon. In providing such a resist layer, a liquid resist or a dry film resist may be used. Further, either a positive type or a negative type may be used.

Next, as shown in FIG. 4A, a pattern 20 that matches the desired pattern is formed on the light shielding layer 16 with a laser 18 or an electron beam, and then post-processing such as development is performed.

Thereby, the photomask 10 as shown in FIG. 4B can be obtained.

In the photomask 10 manufactured in this way, a functional layer (not shown) having functions such as surface protection, antireflection, and antistatic may be further formed on the base material 14 and the light shielding layer 16. .

Thus, the photomask 10 of the present invention is manufactured by the simple process as described above, and the base material 14 is used and stored in the frame 12 made of a material having a thermal linear expansion coefficient of 35 ppm / ° C. or less. Since it is fixed in a tensioned state in the atmosphere, there is almost no dimensional change associated with a change in humidity, and the dimensional change associated with a temperature change can be significantly reduced as compared with a conventional photomask.

For this reason, the photomask of the present invention has a special atmosphere for use or storage in the same way as a photomask using a substrate made of glass, in response to the recent demand for finer patterns and stricter accuracy. This can be dealt with without adjustment, and the manufacturing cost can be reduced.

As mentioned above, although the preferable form of this invention was demonstrated, this invention is not limited to said form and manufacturing method, A various change in the range which does not deviate from the objective of this invention is possible.

[Example 1]
First, a frame 12 made of 42 alloy (thermal linear expansion coefficient: 4 ppm, humidity linear expansion coefficient: 0), outer shape of 430 mm square, frame width of 30 mm, and thickness of 1.0 mm was prepared (FIG. 3A).

Next, an epoxy-based thermosetting adhesive was applied to one surface of the frame 12, and a trade name “ARTON” (manufactured by JSR Corporation) (glass transition temperature: 171 ° C., thermal linear expansion on the adhesive-coated surface. The base material 14 made of a film of 450 mm square and 100 μm thickness obtained by the solution casting method using a rate of 62 ppm and a humidity linear expansion coefficient of 4 ppm is attached so that no slack occurs in an atmosphere of 25 ° C. and 55% RH. Combined.

Next, the adhesive was cured by heating at 160 ° C. for 5 hours, and the base material 14 was fixed to the frame 12 (FIG. 3B).

The obtained frame 12 and the base material 14 fixed to the frame 12 were returned to an atmosphere of 25 ° C. and 55% RH, and the portion of the base material 14 that protruded from the frame 12 was cut with a cutter.

Thereafter, a silver salt photosensitive emulsion was coated on the surface of the base material 14 where the frame 12 was not adhered.

Thereafter, it was dried to provide a light-shielding layer 16 having a thickness of 5 μm to obtain a photomask original plate (FIG. 3C).

The photomask precursor thus obtained was measured for measurement as shown in FIG. 5 using a laser drawing apparatus (DI-2080, manufactured by Pentax Co., Ltd.) in an atmosphere of 25 ° C. and 55% RH. 22 was drawn in four places on the base material 14 so that the distance L between the ratings was 350 mm, and then developed and dried to obtain a photomask (A-1).
[Example 2]
A photomask precursor was obtained in the same manner as in Example 1 except that a composite layer of chromium / chromium oxide having a thickness of 100 nm was deposited instead of coating / drying the silver salt photosensitive emulsion in providing the light shielding layer 16. It was.

A negative resist (manufactured by JSR Corporation: THB-110N) is applied to the light shielding layer 16 of the photomask precursor thus obtained and dried, and then a laser drawing apparatus (DI-2080, manufactured by Pentax Corporation) is applied. The measurement score 22 is drawn at four locations on the base 14 so that the distance L between the scores is 350 mm, and then developed, etched, resist stripped, washed and dried to obtain a photomask ( A-2) was obtained.
[Comparative Example 1]
A photomask (B-1) using a silver salt gelatin emulsion as a light-shielding layer 16 was prepared in the same manner as in Example 1 except that the frame 12 was not provided.
[Comparative Example 2]
A photomask (B-2) was obtained in the same manner as in Example 2 except that the frame 12 was not provided, and a 430 mm square and a chromium / chromium oxide composite layer was used as the light shielding layer 16.
<Tension confirmation test>
The photomask (A-1) obtained in Example 1 was exposed to an atmosphere of “25 ° C., 55% RH” for 24 hours, and then the center was pierced with a household sewing needle in the same atmosphere to make a hole. As a result, it was confirmed that the base material 14 had been tensioned at once.

Similarly, in the atmosphere of “25 ° C., 20% RH”, “25 ° C., 80% RH”, “60 ° C., 55% RH”, the center of the photomask is pierced with a household sewing needle to make a hole. It was confirmed that the base material 14 was in tension as well.

The photomask (A-2) obtained in Example 2 was also “25 ° C., 20% RH”, “25 ° C., 55% RH”, “25 ° C., 80% RH” in the same manner as in Example 1. In the atmosphere of “60 ° C., 55% RH”, the center of the photomask was pierced with a household sewing needle, and a hole was formed. It was confirmed that the base material 14 was also tensioned. It was.
<Measurement test of change in distance between scores due to temperature and humidity changes>
With respect to the photomasks (A-1, A-2, B-1, B-2) of Examples 1 and 2 and Comparative Examples 1 and 2, the change in the distance between the scores accompanying the change in temperature and humidity was “25 ° C. , 80% RH ”,“ 25 ° C., 20% RH ”,“ 60 ° C., 55% RH ”, measured in three different atmospheres. Tables 1 to 3 show the values with the largest dimensional change from the atmosphere.

The measurement was carried out after exposure for 24 hours under three atmospheres. “-” In the table indicates that the distance between the scores is reduced.

As is apparent from Tables 1 to 3, the photomasks (A-1, A-2) fixed to the frame 12 with the base material 14 in a tensioned state have no dimensional change due to humidity change, and change in temperature. It was confirmed that the accompanying dimensional change was remarkably small as compared with the photomasks (B-1, B-2) without the frame 12.

That is, the photomasks (A-1, A-2) of Example 1 and Example 2 obtained by the manufacturing method of the present invention are in response to the recent demands for finer patterns and stricter required accuracy. This shows that the photomask using the base material 14 made of glass can be used without special adjustment of the atmosphere used or stored.

In addition, the dimensional change of the photomask accompanying the temperature change is almost the same as the thermal linear expansion coefficient of the 42 alloy which is the material of the frame 12, and this is because the thermal linear expansion coefficient is further reduced in order to further reduce the dimensional change. This suggests that a small material should be used for the frame.

DESCRIPTION OF SYMBOLS 10 ... Photomask 10a ... Photomask 10b ... Photomask 12 ... Frame 14 ... Base material 16 ... Light shielding layer 18 ... Laser 20 ... Pattern 20a ... Pattern 20b ... Pattern 22 ... Score L ... Distance between scores

Claims

A substrate made of a film or sheet mainly composed of a polymer compound;
A light shielding layer disposed on at least one surface of the substrate;
A frame disposed on at least one surface of the substrate;
A photomask comprised of at least
The photomask is
In an atmosphere where it is used and stored,
A photomask, wherein the base material is fixed to the frame in a tensioned state.
The photomask according to claim 1, wherein the frame is made of a material having a coefficient of thermal expansion of 35 ppm / ° C or less.
The photomask according to claim 1 or 2, wherein the substrate has a thermal linear expansion coefficient larger than a humidity linear expansion coefficient.
4. The photomask according to claim 1, wherein the base material contains a cyclic olefin resin as a main component.