JP5795747B2 - Pellicle frame and pellicle - Google Patents

Description

  The present invention relates to a resin pellicle frame and a pellicle using a resin pellicle frame.

  In the manufacture of semiconductors such as LSI and VLSI, or in the manufacture of liquid crystal displays and the like, a lithography operation is performed in which a pattern is formed by irradiating a semiconductor wafer or a liquid crystal original plate with light. At this time, if dust adheres to the photomask or the reticle, the transferred pattern may be deformed, the edges may become rough, and the background may be stained black. This is because garbage absorbs light or bends it. This operation is normally performed in a clean room. However, it is difficult to always keep the photomask clean, and a pellicle in which a transparent pellicle film is attached to a pellicle frame is used. For example, during lithography, the pellicle was placed on the photomask and adhered to the pellicle film by exposing the focus on the photomask pattern while preventing foreign matter from adhering to the photomask. Transfer is possible without being affected by foreign matter.

  In recent years, the cost reduction of the pellicle has been strongly demanded, and the pellicle frame is the most costly material among the constituent materials of the pellicle. This is because the conventional pellicle frame is formed by machining a metal plate material or square pipe material by machining. For this reason, various studies have been made to reduce the cost of the pellicle frame. For example, Patent Document 1 below describes that a pellicle frame is formed by die casting of an aluminum alloy.

JP 2002-318451 A

  A pellicle frame formed by die casting of an aluminum alloy can be reduced in cost compared to a pellicle frame formed by machining a conventional metal plate or square pipe material by machining. However, the pellicle frame formed by die casting has a long flow distance of the molten metal and easily causes internal defects due to air entrainment during filling, and defects such as pinholes are also likely to occur on the surface. In addition, various elements are added to the aluminum alloy for die casting to improve the flow of molten metal in die casting, and a large amount of intermetallic compounds are easily formed in the pellicle frame obtained by die casting. Defects on the appearance such as white spots and pits are likely to occur on the processed pellicle frame. For these reasons, a pellicle frame formed by die casting of an aluminum alloy is not practically used at present.

  Also, a resin pellicle frame is conceivable as a cost reduction compared to a pellicle frame formed by die casting of an aluminum alloy. However, the rigidity of the resin pellicle frame decreases, and unacceptable bending occurs, or wrinkles occur on the attached pellicle film.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a resin-made pellicle frame with improved rigidity and a pellicle using the pellicle frame.

The pellicle frame according to claim 1, which has been made to achieve the above object, is a resin pellicle frame obtained by melt-pressure molding, and is mixed with a fibrous reinforcing material. A resin film made of a resin that is made of a thermoplastic resin and that covers at least the inner surface of the pellicle frame and is light-resistant to ultraviolet rays has an ultraviolet shielding effect mixed in the resin. It is characterized by being blackened with a substance .

  The pellicle frame described in claim 2 is the pellicle frame described in claim 1, wherein the reinforcing material has a length of 0.2 to 10 mm and a thickness of 0.05 to 20 μm. It is characterized by being.

  The pellicle frame according to claim 3 is the one according to claim 1 or 2, wherein the reinforcing material is made of carbon fiber, aramid fiber, glass fiber, or carbon nanotube. It is selected from the group consisting of:

  The pellicle frame described in claim 4 is the one described in any one of claims 1 to 3, wherein the content of the reinforcing substance is 5 by weight with respect to the thermoplastic resin. It is characterized by being in the range of ˜50%.

  A pellicle frame according to a fifth aspect is the one according to any one of the first to fourth aspects, wherein the melt-pressure molding is injection molding.

  The pellicle frame described in claim 6 is the one described in any one of claims 1 to 5, wherein the thermoplastic resin is polypropylene, acrylonitrile butadiene styrene, polycarbonate, polyethylene terephthalate, polybutylene. It is selected from the group consisting of terephthalate, polyacetal, polyphenylene ether, polyamide, polyphenylene sulfide, polyether ether ketone, and liquid crystal polymer.

A pellicle frame described in claim 7 is described in any one of claims 1 to 6 , wherein the resin film is made of a fluororesin or a silicone resin. To do.

The pellicle frame described in claim 8 is the one described in any one of claims 1 to 7 , wherein the material for blackening the resin coating is iron oxide, titanium dioxide, or carbon black. It is characterized by being.

The pellicle frame described in claim 9 is the one described in any one of claims 1 to 8 , wherein the entire surface of the pellicle frame is covered with the resin film. And

The pellicle frame described in claim 10 is the one described in any one of claims 1 to 9, wherein the resin film covering the inner surface of the pellicle frame is an inner surface made of an adhesive resin. It is characterized by being covered with an adhesive layer.

  A pellicle according to an eleventh aspect is characterized in that the pellicle is affixed to one surface side of the pellicle frame according to any one of the first to tenth aspects.

  Even if the pellicle frame of the present invention is made of resin, it is formed of a thermoplastic resin mixed with a fibrous reinforcing material, and has sufficient rigidity for practical use without causing unacceptable bending. doing. A pellicle using this pellicle frame can be sufficiently put into practical use without causing wrinkles on the attached pellicle film.

It is a perspective view showing an example of a pellicle frame according to the present invention. It is a cross-sectional view of the pellicle frame 10 shown in FIG. It is a perspective view immediately after injection molding of the pellicle frame 10 shown in FIG. It is a perspective view of the pellicle obtained using the pellicle frame 10 shown in FIG.

  An example of a pellicle frame according to the present invention is shown in FIG. FIG. 1 is a perspective view of a rectangular pellicle frame 10, in which a vent hole 12 and jig holes 14, 14 are formed on the side surface of the long side portion. The vent hole 12 penetrates the long side portion of the pellicle frame 10 and is used for venting the inside of the pellicle having a pellicle film attached to one side. The jig hole 14 is a recess opened on the side surface of the long side, and the tip of the moving jig is inserted when the pellicle frame 10 or the pellicle is moved. The corners of the four corners of the pellicle frame 10 are formed to be flat or curved so as to prevent dust generation due to contact with other objects.

  The pellicle frame 10 is formed of a thermoplastic resin mixed with a fibrous reinforcing material. The fibrous reinforcing material preferably has a length of 0.2 to 10 mm and a thickness of 0.05 to 20. As the reinforcing material, a material selected from the group consisting of carbon fiber, aramid fiber, glass fiber, and carbon nanotube can be suitably used. As the content of the fibrous reinforcing material with respect to the thermoplastic resin increases, the elastic modulus and strength of the pellicle frame 10 are improved, and the thermal expansion coefficient is lowered and the dimensional stability is also improved. However, the thermoplastic resin that excessively contains the reinforcing material tends to deteriorate the moldability and the appearance of the obtained pellicle frame 10. Accordingly, the content of the reinforcing substance is 5 to 50% (more preferably 30 to 50%) by weight with respect to the thermoplastic resin. It is preferable because physical properties such as strength of the pellicle frame 10 can be improved.

  This thermoplastic resin is composed of polypropylene, acrylonitrile butadiene styrene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyphenylene ether, polyamide, polyphenylene sulfide, polyether ether ketone, liquid crystal polymer from the viewpoint of strength, moldability, etc. Those selected from the group are preferred. Among these, polyamide and polyphenylene sulfide are preferable from the viewpoint of rigidity, and polyether ether ketone is preferable from the viewpoint of light resistance. In addition, a polyimide resin, an epoxy resin, or the like that exhibits thermoplasticity can be used. In addition to the reinforcing substance, for example, pigments such as iron oxide for blackening and titanium dioxide, carbon black, and the like may be mixed in these thermoplastic resins.

  The pellicle frame 10 shown in FIG. 1 is covered with a resin coating 16 having light resistance to ultraviolet rays, as shown in FIG. 2A, which is a cross-sectional view taken along line XX. It is preferable. Light resistance can be improved by protecting the thermoplastic resin forming the pellicle frame 10 against ultraviolet rays irradiated by lithography or the like, and dust from the reinforcing material in the thermoplastic resin forming the inside of the pellicle frame 10 can be prevented. This is because it can be prevented. Further, as shown in FIG. 2B, by covering the entire surface of the pellicle frame 10 with the resin film 16, dust generation from the reinforcing material in the thermoplastic resin that forms the entire surface of the pellicle frame 10 can be prevented. .

  For the resin coating 16, a resin that is different from the thermoplastic resin forming the inner surface of the pellicle frame 10 and has light resistance to ultraviolet rays, for example, a fluororesin or a silicone resin can be suitably used. The resin coating is preferably black. The blackening of the resin coating 16 can be performed by blending iron oxide, titanium dioxide, carbon black, or the like in a resin that has light resistance to ultraviolet rays. Among them, it is preferable to blend iron oxide that has a high ultraviolet shielding effect and does not cause deterioration. However, when the thermoplastic resin forming the pellicle frame 10 is blackened, the resin coating 16 may be transparent.

  Further, as shown in FIG. 2C, the entire surface of the pellicle frame 10 is covered with a resin coating 16, and the inner surface of the resin coating 16 of the pellicle frame 10 is further covered with an inner surface adhesive layer 18 made of an adhesive resin. As a result, it is possible to prevent the foreign matter attached to the inner surface of the pellicle frame 10 from falling off, and to further improve the light resistance and dust generation property of the pellicle frame 10 against ultraviolet rays. In particular, when the resin coating 16 contains a blackening material such as iron oxide, dust generation due to the peeling of the blackening material in the resin coating 16 can be effectively prevented by the inner surface adhesive layer 18. The surface adhesive layer 18 can be formed by applying adhesive silicone resin, acrylic resin, or the like. 2A, even if the resin film 16 is formed only on the inner surface of the pellicle frame 10, the resin film 16 may be covered with the inner surface adhesive layer 18.

  Here, when the thermoplastic resin forming the pellicle frame 10 has sufficient light resistance, for example, polyetheretherketone blended with carbon fiber as a reinforcing material is black and has sufficient light resistance. The formed pellicle frame 10 can be put to practical use by applying an adhesive silicone resin or the like to the inner surface thereof to form the resin film 16.

  The pellicle frame 10 shown in FIG. 1 can be formed by melt-pressure molding a thermoplastic resin mixed with a fibrous reinforcing material. As this melt pressure molding, injection molding can be suitably employed. The reinforcing material may be mixed with the thermoplastic resin pellets at the time of injection molding, but it is preferable to use thermoplastic resin pellets in which the reinforcing material is uniformly dispersed in advance. A conventional pellicle frame by injection molding using a thermoplastic resin is greatly inferior to a metal cutting product in terms of dimensional accuracy. The pellicle frame 10 of FIG. 1 obtained by injection molding a thermoplastic resin mixed with a fibrous reinforcing material to such a conventional resin pellicle frame has reduced dimensional errors due to thermal expansion, and has improved dimensional accuracy. It can be set to a practical range.

  FIG. 3 shows a pellicle frame 10a taken out from an injection mold. The pellicle frame 10a has a gate portion 20 attached to one end face thereof. The pellicle frame 10 from which the gate portion 20 has been removed is lightly hand-finished on both end surfaces of the pellicle frame 10 or subjected to very slight mechanical cutting in order to smooth the removal trace of the gate portion 20 and to remove burrs on the mating surface of the mold. It is preferable to do. Further, the pellicle frame 10 shown in FIG. 1 can be obtained by forming the vent hole 12 and the jig holes 14 and 14 shown in FIG. 1 on the side surface of the long side portion of the pellicle frame 10a shown in FIG. it can. In addition, at the time of injection molding of the pellicle frame 10a, it is possible to mold the vent hole 12 and the jig holes 14 and 14 simultaneously, but the mold structure becomes complicated.

  As shown in FIG. 2 (a) or FIG. 2 (b), a fluororesin or silicone resin is applied to the inner surface or the entire surface of the obtained pellicle frame 10 by spray coating, roll coating, dipping, or the like, as necessary. Thus, the resin film 16 is formed. This application method can be appropriately selected according to the material to be applied. Further, the inner surface adhesive layer 18 shown in FIG. 2C is applied to the inner surface of the formed resin coating 16 as necessary by applying an adhesive silicone resin, an acrylic resin or the like by spray application, roll application, dipping, or the like. Form.

  A pellicle using the pellicle frame 10 of FIG. 1 is shown in FIG. The pellicle 30 in FIG. 4 has a pellicle film 22 attached to one surface side of the pellicle frame 10 via a pellicle film adhesive layer (not shown), and a mask adhesive layer 26 attached to the other surface side. The mask adhesive layer 26 is protected by a separator 28 provided with a release layer on a film of polyethylene terephthalate (PET) or the like. The vent hole 12 formed on the side surface of the long side portion of the pellicle frame 10 is a filter composed of a porous film of polytetrafluoroethylene (PTFE) or the like in order to prevent dust and the like from entering the pellicle 30. 24.

  The pellicle 30 shown in FIG. 4 is reduced in cost as a whole because the pellicle frame 10 in FIG. 1 is produced at low cost by injection molding or the like while maintaining the same performance as the conventional metal pellicle frame. Can be achieved. In addition, the pellicle 30 of FIG. 4 is entirely made of resin, and has an advantage different from that of a conventional metal pellicle frame. That is, in recent years, in an exposure environment using an ArF laser light source (193 nm) or the like, a foreign matter product (haze) on the surface of the mask or pellicle during exposure has become a problem. As a cause of this, the involvement of acid or alkaline ion components in a metal pellicle frame (for example, an alumite film of an aluminum pellicle frame) is suspected. Since the pellicle frame 10 of FIG. 1 does not contain any ionic components that cause foreign product (haze), it can be expected to suppress the generation of foreign product in these applications.

  The pellicle 30 can be applied as long as the pellicle frame 10 can be formed by melt pressure molding, and is not particularly limited. However, as the pellicle 30 becomes larger, the molding machine for the pellicle frame 10 becomes larger, which increases the molding die cost and becomes an obstacle to cost reduction. Therefore, the applicable pellicle 30 has a side length of 100. It is good to set it as the range of-1400mm, Preferably it is 100-800mm, More preferably, it is 100-600mm.

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

(Example)
A carbon fiber-containing thermoplastic resin (trade name: NXMR-C-40B manufactured by Mitsubishi Rayon Co., Ltd.) containing 40% carbon fiber having a length of 2 to 6 mm and a thickness of 5 to 7 μm in polyamide is shown in FIG. A rectangular pellicle frame 10 shown in FIG. A gate part 20 was formed on the pellicle frame 10a shown in FIG. 3 taken out from the injection-molded and cooled mold. Both end faces of the pellicle frame 10 obtained by cutting the gate part 20 were chamfered by 0.2 mm. Furthermore, the edge part of the pellicle frame 10 was lightly hand-finished with sandpaper to remove the removal marks of the gate part 20 and burrs on the die-mating surface. At this time, the vent hole 12 and the jig holes 14 and 14 were formed in the side surface of the long side part of the pellicle frame 10 by machining to form the pellicle frame 10 shown in FIG. The dimensions are 149 × 113 × height 4.7 mm and inner dimension 145 × 109 mm.

  The pellicle frame 10 was carried into a Class 10 clean room, washed with pure water and a surfactant, and sufficiently dried. Thereafter, a solution obtained by diluting a fluorine-based resin (trade name; manufactured by Cytop Asahi Glass Co., Ltd.) with a fluorine-based solvent and further mixing iron oxide (trade name; manufactured by Toda Color Toda Kogyo Co., Ltd.) is sprayed on the pellicle frame 10. The resin coating 16 having a thickness of 15 μm was formed on the entire surface of the pellicle frame 10 as shown in FIG. Further, a silicone adhesive diluted with toluene was sprayed onto the inner surface of the pellicle frame 10 to form an inner surface adhesive layer 18 having a thickness of 10 μm on the inner surface of the resin coating 16 as shown in FIG. .

  Next, a silicone pressure-sensitive adhesive (made by Shin-Etsu Chemical Co., Ltd .; trade name KR3700) is applied to the upper surface of the pellicle frame 10 as a pellicle film adhesive layer, and a silicone pressure-sensitive adhesive (Shin-Etsu Chemical Co., Ltd.) is used as a mask pressure-sensitive adhesive layer 26 on the lower surface. Co., Ltd .; trade name KR3700) was applied, dried and cured. The mask adhesive layer 26 was protected by attaching a separator 28, and the vent hole 12 was covered with a porous membrane filter 24 made of polytetrafluoroethylene (PTFE). Further, a pellicle film 22 made of a fluororesin and having a thickness of about 0.8 μm was stuck on the pellicle film adhesive layer, and the excess film on the outside was cut out with a cutter to obtain a pellicle 30 shown in FIG.

  When the appearance of the pellicle 30 was inspected with a condenser lamp in a dark room, no defects due to injection molding or resin were found on the surface. Further, when the pellicle 30 was handled, there was no particular problem such as wrinkles on the pellicle film 22. Next, when this pellicle 30 was placed on a surface plate and the amount of bending of the pellicle frame 10 was measured, the amount of bending was 0.22 mm on one side at the center of the long side and 0.1 mm on one side at the center of the short side. However, it was sufficiently acceptable for use.

(Comparative example)
A pellicle was manufactured in the same process as in the example except that a pellicle frame having the same shape and dimensions as in the example was replaced with polyamide (no fibrous reinforcing material) instead of the carbon fiber-containing thermoplastic resin. . When this pellicle was placed on a surface plate and the amount of bending of the pellicle frame was measured, the amount of bending was about 1.0 mm on one side at the center of the long side and about 0.5 mm on one side at the center of the short side. Further, when the pellicle is handled, if the center of the long side portion of the pellicle frame is held, wrinkles are immediately generated in the pellicle film. Further, in this pellicle frame, a twist that seems to be caused by the molding process was generated, and when placed on a surface plate, the two corners were lifted by about 0.5 mm each. A pellicle frame in which such a twist has occurred cannot be used for a pellicle.

  The pellicle frame and pellicle according to the present invention can be used in the manufacturing process of a semiconductor device, a printed board, a liquid crystal, an organic EL display, or the like.

  10 is a pellicle frame, 10a is a pellicle frame immediately after injection molding, 12 is a vent hole, 14 is a jig hole, 16 is a resin film, 18 is an inner surface adhesive layer, 20 is a gate portion, 22 is a pellicle film, 24 is a filter, 26 is a mask adhesive layer, 28 is a separator, and 30 is a pellicle.

Claims (11)

A resin pellicle frame obtained by melt-pressure molding is formed of a thermoplastic resin mixed with a fibrous reinforcing material ,
The resin film made of a resin having light resistance to ultraviolet rays and covering at least the inner surface of the pellicle frame is blackened with a substance having an ultraviolet shielding effect mixed in the resin. Pellicle frame.   2. The pellicle frame according to claim 1, wherein the reinforcing substance has a length of 0.2 to 10 mm and a thickness of 0.05 to 20 μm.   The pellicle frame according to claim 1 or 2, wherein the reinforcing substance is selected from the group consisting of carbon fiber, aramid fiber, glass fiber, and carbon nanotube.   The pellicle frame according to any one of claims 1 to 3, wherein a content of the reinforcing substance is in a range of 5 to 50% by weight with respect to the thermoplastic resin.   The pellicle frame according to any one of claims 1 to 4, wherein the melt-pressure molding is injection molding.   The thermoplastic resin is selected from the group consisting of polypropylene, acrylonitrile butadiene styrene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyphenylene ether, polyamide, polyphenylene sulfide, polyether ether ketone, and liquid crystal polymer. The pellicle frame according to any one of claims 1 to 5, wherein the pellicle frame is characterized. The pellicle frame according to any one of claims 1 to 6, wherein the resin film is made of a fluororesin or a silicone resin. The pellicle frame according to any one of claims 1 to 7, wherein the substance that blackens the resin film is iron oxide, titanium dioxide, or carbon black . The pellicle frame according to any one of claims 1 to 8 , wherein the entire surface of the pellicle frame is covered with the resin film . The pellicle frame according to any one of claims 1 to 9 , wherein the resin film covering the inner surface of the pellicle frame is covered with an inner surface adhesive layer made of an adhesive resin.   A pellicle, wherein a pellicle is attached to one side of the pellicle frame according to any one of claims 1 to 10.

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