JP2009288265A - Pellicle for lithography - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pellicle for lithography which is less deformed and distorted. <P>SOLUTION: In the pellicle for lithography, each of at least two jig holes near both ends of two long sides of a rectangular pellicle frame is located ≤10 mm inside from one end part of each long side. Desirably, the length of long sides of the pellicle frame is 140 to 300 mm, and more desirably, it is 140 to 230 mm. It is desirable that a pair of jig holes facing each other out of a plurality of jig holes provided near both ends of two log sides of the pellicle frame are long in a direction of long sides of the frame. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pellicle for lithography used as a dust mask for a lithography mask when manufacturing a semiconductor device such as an LSI or a VLSI or a liquid crystal display panel.

  In the manufacture of semiconductors such as LSI and VLSI or the manufacture of liquid crystal display panels, patterns are produced by irradiating a semiconductor wafer or liquid crystal master plate with light, and if dust adheres to the exposure master used in this case, Because this dust absorbs light or bends it, the transferred pattern may be deformed, the edges may be rough, and the ground may become black, resulting in damage to dimensions, quality, appearance, etc. There was a problem of being. In the present invention, the “exposure master” is a general term for a lithography mask and a reticle.

Although these operations are usually performed in a clean room, it is difficult to keep the exposure original plate clean even in this clean room, so a pellicle that allows exposure light for dust prevention to pass through the surface of the exposure original plate well is used. The method of sticking is taken.
In this case, dust does not adhere directly to the surface of the exposure original plate, but instead adheres to the pellicle film, so if the focus is set on the pattern of the exposure original plate during lithography, the dust on the pellicle film has no relation to the transfer. Become.

  The basic configuration of the pellicle includes a pellicle frame and a pellicle film stretched on the pellicle frame. The pellicle film is made of nitrocellulose, cellulose acetate, a fluorine-based polymer or the like that transmits light used for exposure (g-line, i-line, 248 nm, 193 nm, 157 nm, etc.) well. The pellicle frame is made of an aluminum alloy such as A7075, A6061, and A5052 subjected to black alumite treatment, stainless steel, polyethylene, or the like. A good solvent for the pellicle film is applied to the upper part of the pellicle frame, and the pellicle film is air-dried and bonded (see Patent Document 1) or bonded with an adhesive such as an acrylic resin, an epoxy resin, or a fluororesin (see Patent Document 2). ). Furthermore, since the exposure original plate is mounted on the lower part of the pellicle frame, the pressure-sensitive adhesive layer for protecting the pressure-sensitive adhesive layer made of polybutene resin, polyvinyl acetate resin, acrylic resin or silicone resin, and the pressure-sensitive adhesive layer is used. Provide a liner.

  The pellicle is placed so as to surround the pattern area formed on the surface of the exposure original plate. Since the pellicle is provided to prevent dust from adhering to the exposure original plate, the pattern region and the outside of the pellicle are isolated so that dust outside the pellicle does not adhere to the pattern surface.

In recent years, LSI design rules have been miniaturized to sub-quarter microns, and accordingly, the wavelength of exposure light sources has been shortened, that is, g-rays (436 nm) by mercury lamps, which has been the mainstream until now. , I-line (365 nm), KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ laser (157 nm), and so on. As the exposure wavelength becomes shorter and the exposure resolution becomes higher, there is a concern that the distortion and deformation of the pattern, which has not been a problem until now, affect the yield. The distortion and deformation of the pattern largely depends on the distortion and deformation of the exposure original plate itself. The main cause of the above problems is distortion deformation accompanying pellicle pasting.
It has been found that the adverse effect on the exposure original plate due to the pellicle attachment is affected by the deformation and distortion of the pellicle itself.

JP 58-219033 US Pat. No. 4,861,402

  The present invention has been made to solve the above problems. That is, the problem to be solved by the present invention is to provide a lithography pellicle with reduced deformation and distortion.

Said subject was solved by the means as described in the following (1). It lists below with (2)-(7) which is a preferable embodiment of this invention.
(1) At least two jig holes provided in the vicinity of both ends of the two long sides of the rectangular pellicle frame are all installed within 10 mm from either end of each long side. , Pellicle for lithography,
(2) The pellicle for lithography according to (1), wherein the length of the long side of the pellicle frame is 140 mm or more and 300 mm or less,
(3) The pellicle for lithography according to (1) or (2), wherein the length of the long side of the pellicle frame is 140 mm or more and 230 mm or less,
(4) A pair of jig holes facing each other of a plurality of jig holes provided in the vicinity of both ends of the two long sides of the pellicle frame are elongated holes in the frame long side direction, any of (1) to (3) A lithography pellicle according to claim 1,
(5) The pellicle for lithography according to any one of (1) to (4), wherein the pellicle frame is an aluminum alloy pellicle frame having a black alumite film,
(6) The pellicle for lithography according to any one of (1) to (4), wherein the pellicle frame is an aluminum alloy pellicle frame having a polymer electrodeposition coating film,
(7) The pellicle for lithography according to any one of (1) to (6), wherein the height of the pellicle frame is 5 mm or less.

  Since at least two jig holes provided near both ends of the two long sides of the rectangular pellicle frame are installed within 10 mm from either end of each long side, the pellicle manufacturing jig It has become possible to reduce the distortion and deformation of the frame that occurs when the pellicle frame is fixed as compared with the conventional case.

The pellicle for lithography (hereinafter also simply referred to as “pellicle”) of the present invention has at least two jigs provided near both ends of two long sides of a rectangular pellicle frame (hereinafter also simply referred to as “frame”). All the holes are installed within 10 mm from either end of each long side.
That is, the pellicle for lithography of the present invention is a lithography pellicle in which a pellicle film is stretched on one end face of a rectangular pellicle frame via a pellicle film adhesive, and an exposure original plate adhesive is provided on the other end face. It is characterized in that at least two jig holes for each long side provided in the vicinity of both ends of the two long sides of the pellicle frame are installed within 10 mm from either end of each long side. . The above jig hole can be effectively used for manufacturing a pellicle and subsequently handling it to be attached to or peeled from the exposure original plate. The jig hole is preferably equidistant from any end of each long side, and preferably provided at a position of 2 to 10 mm.
The jig hole being installed within 10 mm from the end of the long side means that the center of the circular jig hole or the central part of the long hole jig hole in the long side direction is set to 10 mm or less. This means that the entire jig hole may not be installed within 10 mm.
Furthermore, it is preferable that the pair of jig holes facing each other has a long hole structure in the long side direction. More preferably, one pair of the two pairs of jig holes facing each other is a circular jig hole, and the other pair has a structure of a long hole.
Neither circular nor elongated jig holes are through holes. The circular jig hole is preferably a conical connected depression at the end of a cylinder.
In the pellicle of the present invention, the pellicle frame preferably has a long side length of 140 mm to 300 mm, and more preferably 140 mm to 230 mm. The height of the pellicle frame is particularly preferably 5 mm or less. In the present invention, by applying a jig hole to these pellicles, it was possible to provide a pellicle with significantly less distortion and less deformation than conventional ones.
Hereinafter, the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, a pellicle 10 for lithography according to the present invention has a pellicle film 1 stretched on an upper end surface of a pellicle frame 3 via a pellicle film bonding adhesive layer 2. In this case, the pellicle 10 Is usually formed on the lower end surface of the pellicle frame 3, and a liner (not shown) is peeled off from the lower end surface of the reticle bonding adhesive layer 4. It is made by sticking possible. Further, a pressure adjusting hole (vent hole) 6 may be provided in the pellicle frame 3, and a dust removing filter 7 may be further provided for the purpose of particle removal.

In this case, the size of these pellicle constituent members is the same as that of a normal pellicle, for example, a pellicle for semiconductor lithography, a pellicle for manufacturing a large liquid crystal display panel, and the material thereof is also a known material as described above. be able to.
The type of pellicle film is not particularly limited, and for example, an amorphous fluoropolymer conventionally used for excimer laser is used. Examples of the amorphous fluoropolymer include Cytop (trade name, manufactured by Asahi Glass Co., Ltd.), Teflon (registered trademark) AF (trade name, manufactured by DuPont), and the like. These polymers may be used by dissolving in a solvent as necessary when preparing the pellicle film. For example, these polymers can be appropriately dissolved in a fluorine-based solvent.

  As for the base material of the pellicle frame used in the present invention, a conventionally used aluminum alloy material, preferably JIS A7075, JIS A6061, JIS A5052 material or the like is used. As long as the strength of the is secured, there is no particular limitation. The surface of the pellicle frame is preferably roughened by sandblasting or chemical polishing before providing the polymer coating. In the present invention, a conventionally known method can be adopted as the method for roughening the surface of the frame. A method in which the surface of the aluminum alloy material is roughened by blasting the surface with stainless steel, carborundum, glass beads or the like, and further chemically polishing with NaOH or the like is preferable.

FIG. 2 shows one long side of the pellicle frame as viewed from the front. In the four jig holes shown in FIG. 2, the outer two jig holes 11 and 11A are jig holes according to the present invention, and the inner two jig holes 12 and 12 are conventionally provided. . The rightmost jig hole 11A in FIG. 2 has a long hole shape in the long side direction. However, if the pair of jig holes facing each other has a long side shape, it may be provided on either the left or right side. The long side shape is preferably a shape in which semicircles are joined to both ends of a rectangle.
The shape of the jig hole in the depth direction is not specified, and may be a recess having a taper at the tip of the cylinder as long as it does not penetrate.

  FIG. 3 shows a pellicle frame fixed to a manufacturing jig. The manufacturing jig 13 has a structure in which the pellicle frame 3 is fixed by four pins 14 and 15. The pin tip of the manufacturing jig has a 45 ° taper shape from a 3 mmφ cylinder. Preferably, the two jig holes 11 and 11A provided on one long side are fixed to the manufacturing jig 13 by a fixing pin 14, and the two jig holes 11 and 11A provided on the other long side are springs. It is fixed to the production jig 13 by a fixing pin 15 having a mechanism. Any of the fixing pins is preferably a tapered pin having a tapered shape at the tip. The pin having the spring mechanism is designed to minimize the force applied in the insertion direction of the jig hole of the pellicle frame. When the pellicle frame expands due to heating or the like, the elements that expand in the short side direction can be released by the spring structure of the pin. By allowing the tip of the taper pin to move relative to the pellicle frame within the pair of elongated holes, the pellicle frame is continuously held from both sides inside the manufacturing jig without applying excessive force to the pellicle frame. It becomes possible.

The pellicle of the present invention can exhibit a particular advantage over a thin pellicle having a long side of 140 mm or more and a frame height of 5 mm or less. The frame height is preferably 1 to 5 mm, more preferably 2 to 5 mm. Although there is no restriction | limiting in particular in the upper limit of the long side of a pellicle frame, As mentioned above, it is preferable that it is 300 mm or less, and it is more preferable that it is 230 mm or less. The short side of the pellicle frame is not particularly limited as long as it is equal to or shorter than the long side. Since these pellicle frames have a structure that is very distorted, it is possible to grip the frame at a slightly high strength portion by installing a jig hole for handling near the corner. Further, as the length of the long side of the frame becomes longer, the expansion of the frame at the time of heating or the like becomes larger, so it is important to secure a clearance that absorbs the length change in the direction of the long side of the frame.
The diameter of the jig hole can be appropriately selected, but is preferably 1 to 2 mm. When the hole is a long hole, it is preferably 1 to 2 mm horizontally long.

In the present invention, the pellicle frame preferably has a black alumite film and / or a polymer film, and more preferably has a polymer electrodeposition coating film. The pellicle frame is preferably an aluminum alloy pellicle frame, and particularly preferably an aluminum alloy pellicle frame having a black alumite film and / or a polymer electrodeposition coating film.
As a method of forming a black alumite film on the surface of the pellicle frame, generally, it is treated with an alkali treatment bath such as NaOH for several tens of seconds, then anodized in a dilute sulfuric acid aqueous solution, and then black dyed and sealed. A black oxide film can be provided on the surface.

Moreover, although a polymer film (polymer coating) can be provided by various methods, spray coating, electrostatic coating, electrodeposition coating, etc. are generally mentioned. In the present invention, it is preferable to provide a polymer film by electrodeposition coating.
For electrodeposition coating, either thermosetting resin or ultraviolet curable resin can be used. Moreover, either anion electrodeposition coating or cationic electrodeposition coating can be used for each. In the present invention, since UV resistance is also required, anionic electrodeposition coating of a thermosetting resin is preferable from the viewpoint of coating stability, appearance, and strength.

The thickness of the electrodeposition-coated polymer film is preferably 5 to 30 μm, and more preferably 5 to 20 μm.
Coating equipment and electrodeposition coatings used for these purposes can be purchased and used as commercial products from several Japanese companies. For example, an electrodeposition paint marketed under the trade name of Elecoat from Shimizu Corporation can be exemplified. “Elecoat Frosty W-2” and “Elecoat Frosty ST Satina” are matte-type thermosetting anion-type electrodeposition paints and can be preferably used in the present invention.

  When the polymer coating is a black matte electrodeposition coating film, the emissivity is preferably 0.80 to 0.99. Here, the “emissivity” is the total radiation energy P based on a black body (an ideal object that absorbs all wavelengths incident on its surface and does not reflect or transmit) and the energy P1 emitted by the object. It means (P1 / P) obtained by the ratio, and is a value measured by a radiation sensor TSS-5X manufactured by Japan Sensor Co., Ltd.

  Hereinafter, the present invention will be specifically described by way of examples. The “mask” in the examples and comparative examples is described as an example of the “exposure original plate”, and it is needless to say that the same can be applied to the reticle.

Example 1
As a pellicle frame, a frame with black anodized with a frame outer size of 150 mm × 122 mm × 3.5 mm and a frame thickness of 2 mm was prepared. From the outside of the pellicle frame, the hole diameter is 1.6mmφ and the depth is 1.2mm. Jig holes were provided (7.5 mm from both ends of the long side). Further, both sides of the pair of jig holes facing each other in the lateral direction were enlarged by 0.8 mm to form 3.2 mm × 1.6 mm long holes. The flatness of the frame was measured with a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. The frame was set in a manufacturing jig corresponding to a 135 pitch jig hole, a mask adhesive was applied in accordance with a conventional pellicle manufacturing process, and allowed to stand for 60 minutes, and then heated with a high frequency induction heating device. After the film adhesive was applied and dried, the pellicle film was bonded to complete the pellicle. When the mask adhesive was peeled from the completed pellicle and the flatness was measured using a three-dimensional measuring device BH506 manufactured by Mitutoyo Corporation, it was 9 μm.
The “flatness” described above is a size defined by the sum of the unevenness Max and Min from the virtual plane of the pellicle frame.

(Example 2)
As a pellicle frame, a frame with an outer electrode dimension of 149 mm × 115 mm × 3.5 mm and an electrodeposition polymer coat with a frame thickness of 2 mm was prepared. A handling jig hole was provided on the long side of the frame in the same manner as in Example 1. The flatness of the frame was measured with a three-dimensional measuring device BH506 manufactured by Mitutoyo Corporation. The frame was set in a manufacturing jig corresponding to a 135 pitch jig hole, a mask adhesive was applied in accordance with a conventional pellicle manufacturing process, and allowed to stand for 60 minutes, and then heated with a high frequency induction heating device. After the film adhesive was applied and dried, the pellicle film was bonded to complete the pellicle. The mask adhesive was peeled from the completed pellicle, and the flatness was measured using a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. As a result, it was 9 μm.

(Example 3)
As a pellicle frame, a frame with black anodized with a frame outer size of 149 mm × 113 mm × 4.5 mm and a frame thickness of 2 mm was prepared. A handling jig hole was provided on the long side of the frame in the same manner as in Example 1. The flatness of the frame was measured with a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. The frame was set in a manufacturing jig corresponding to a 135 pitch jig hole, a mask adhesive was applied in accordance with a conventional pellicle manufacturing process, and allowed to stand for 60 minutes, and then heated with a high frequency induction heating device. After the film adhesive was applied and dried, the pellicle film was bonded to complete the pellicle. The mask adhesive was peeled off from the completed pellicle, and the flatness was measured using a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. The result was 6 μm.

(Comparative Example 1)
As a pellicle frame, a frame with black anodized with a frame outer size of 150 mm × 122 mm × 3.5 mm and a frame thickness of 2 mm was prepared. A jig hole with a hole diameter of 1.6φ and a depth of 1.2 was provided at a position where the center of the jig hole for handling is 135 pitches at the center of the long side of the frame and 1.75 mm from the film adhesive application end surface. . The flatness of the frame was measured with a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. The frame was set in a manufacturing jig corresponding to a 135 pitch jig hole, a mask adhesive was applied in accordance with a conventional pellicle manufacturing process, and allowed to stand for 60 minutes, and then heated with a high frequency induction heating device. After the film adhesive was applied and dried, the pellicle film was bonded to complete the pellicle. The mask adhesive was peeled from the completed pellicle, and the flatness was measured using a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. The result was 25 μm.

(Comparative Example 2)
As a pellicle frame, a frame with black anodized with a frame outer size of 150 mm × 122 mm × 3.5 mm and a frame thickness of 2 mm was prepared. A jig hole with a hole diameter of 1.6φ and a depth of 1.2 is provided at a position where the center of the handling jig hole is 104 pitches at the center of the long side of the frame and 1.75 from the film adhesive application end surface. . The flatness of the frame was measured with a three-dimensional measuring instrument BH506 manufactured by Mitutoyo Corporation. The frame was set in a manufacturing jig corresponding to a 135 pitch jig hole, a mask adhesive was applied in accordance with a conventional pellicle manufacturing process, and allowed to stand for 60 minutes, and then heated with a high frequency induction heating device. After the film adhesive was applied and dried, the pellicle film was bonded to complete the pellicle. The mask adhesive was peeled off from the completed pellicle, and the flatness was measured using a three-dimensional measuring device BH506 manufactured by Mitutoyo Corporation. The result was 55 μm.

It is explanatory drawing which shows the structural example of a pellicle. It is the figure which showed the pellicle frame long side and the jig hole. It is the figure which showed the pellicle frame hold | gripped by the pellicle manufacturing jig.

Explanation of symbols

1: Pellicle membrane 2: Adhesive layer 3: Pellicle frame 4: Adhesive layer 5: Exposure master 6: Pressure adjustment hole (vent)
7: Filter for dust removal 10: Pellicle 11: Jig hole (circular) (present invention)
11A: Jig hole (long hole) (present invention)
12: Jig hole (prior art)
13: Manufacturing jig 14: Pin (fixed)
15: Pin (with spring mechanism)

Claims (7)

  For lithography, characterized in that at least two jig holes provided in the vicinity of both ends of the two long sides of the rectangular pellicle frame are located within 10 mm from either end of each long side. Pellicle.   The pellicle for lithography according to claim 1, wherein the length of the long side of the pellicle frame is 140 mm or more and 300 mm or less.   The pellicle for lithography according to claim 1 or 2, wherein a length of a long side of the pellicle frame is 140 mm or more and 230 mm or less.   The pair of jig holes facing each other of a plurality of jig holes provided in the vicinity of both ends of the two long sides of the pellicle frame are elongated holes in the frame long side direction. Pellicle for lithography.   The pellicle for lithography according to any one of claims 1 to 4, wherein the pellicle frame is an aluminum alloy pellicle frame having a black alumite film.   The pellicle for lithography according to any one of claims 1 to 4, wherein the pellicle frame is an aluminum alloy pellicle frame having a polymer electrodeposition coating film.   The pellicle for lithography according to any one of claims 1 to 6, wherein a height of the pellicle frame is 5 mm or less.

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