JP2005092067A - Method of forming protective layer coating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a method of forming a protection film for a mask for exposure that never stains a peripheral edge and a reverse surface of a base material with protecting layer paint, has film thickness uniformity in a surface and superior economy and operability to improve quality. <P>SOLUTION: As a method of forming a film surface protecting layer as an upper layer of the mask for exposure which uses glass as its base material, disclosed is the method for forming a protecting layer characterized in that protecting layer paint is applied in a desired image shape on the base material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for forming a protective layer coating film, and more particularly to a method for forming a film surface protective layer on an upper layer of an exposure mask made of glass.

  According to Isao Tanabe, Yoichi Takehana, and Morihisa Homoto, “The Story of Photomask Technology” Industrial Research Council (1996), in recent years, with the fine patterning of printed circuit boards, exposure masks for manufacturing printed circuit boards have been developed. The substrate is moving from film to glass. In addition, exposure masks for manufacturing liquid crystal displays, LSIs, etc. require high precision, so they cannot be handled by films that easily change in dimensions due to changes in humidity, tension, etc., and need to use glass as the base material. is there.

  As an exposure mask material based on glass, an emulsion mask having a silver halide emulsion layer on a substrate is inexpensive and simple. Since the emulsion mask uses gelatin as a binder for the image forming layer, it is easily scratched. In particular, since the substrate is hard, there is a problem that the image is damaged only by lightly hitting a sharp object.

  In addition, the chromium mask provided with the metal chromium layer has a very high metal strength and excellent durability, but the metal chromium layer has a thin film thickness of around 0.1 μm and is hard during cleaning and exposure. There is a problem that point failures such as pinholes occur due to contact with foreign matter.

  We have also proposed an exposure mask (hereinafter referred to as a DTR mask) in which a metallic silver image is directly formed on a transparent substrate by a diffusion transfer method (see, for example, Patent Documents 1 and 2). The image forming layer of the DTR mask is relatively strong because it does not contain gelatin unlike an emulsion mask, but there is a strong demand for making it stronger.

Conventionally, methods for forming a protective layer coating on such a glass substrate include dip coating, flow coating, spray coating, roll coating, die head coating, and the like. However, in the dip coating method and the flow coating method, the paint adheres to the peripheral edge and the back surface of the glass substrate and causes the generation of foreign matter, which not only requires an extra step for cleaning it but also deteriorates workability. It leads to quality deterioration. The spin coating method is very disadvantageous economically because most of the paint is discarded without being reused. The roll coating method and the die head coating method are advantageous in that the paint can be used efficiently, but both have poor film thickness accuracy at the coating start portion, and it is difficult to apply a thin film to a small size substrate. The coating method is described in detail in Yuji Harasaki's “Progress of Coating Technology” General Technology Center (1988). In this way, a method for forming a film surface protective layer on a glass-based exposure mask has been proposed. However, it is economical to apply a protective layer coating on a desired image on the substrate. An effective technique for a method for forming a protective coating film that is excellent in workability and achieves quality improvement is not disclosed.
JP 2000-10258 A JP 2000-310846 A

  An object of the present invention is to provide a mask for an exposure mask that achieves an improvement in quality with high uniformity of film thickness in the surface, excellent economic efficiency and workability, without staining the peripheral edge and back surface of the substrate with a protective layer paint. The purpose is to propose a method of forming a film.

  As a result of investigations, the present inventors have found that at least one photosensitive halogenated emulsion layer is formed on the glass substrate, and the blackened silver formed in the silver halide emulsion layer by developing after exposure. In an exposure mask on which an image is formed, a protective layer paint for forming a film surface protective layer after forming an image on an upper layer on the same side as the image forming layer with respect to the glass substrate is applied to the base by a scanning nozzle discharge method. It has been found that the above-mentioned problems can be solved by coating a desired image on the material.

  In the exposure mask in which at least one light-shielding film on the glass substrate is made of metallic chromium, a protective layer that forms a film surface protective layer after image formation on the same layer as the image forming layer with respect to the glass substrate It has been found that the above-mentioned problems can be solved by coating the coating material in a desired image form on the substrate by a scanning nozzle discharge coating method.

  It has at least one photosensitive silver halide emulsion layer on a glass substrate, has physical development nuclei between the silver halide emulsion layers, and develops the chemically developed silver by developing after exposure. In an exposure mask formed by forming on the glass substrate and then removing the silver halide emulsion layer and leaving only the metal silver image formed by physical development on the glass substrate, the image is formed on the glass substrate. The above problem is solved by coating a protective layer paint for forming a film surface protective layer on an upper layer on the same side as the forming layer in a desired image form on the substrate by a scanning nozzle discharge coating method. I found out.

  According to the present invention, protection for an exposure mask that achieves quality improvement with high in-plane film thickness uniformity, economic efficiency and workability without staining the peripheral edge and back surface of the substrate with a protective layer coating. A film formation method can be proposed.

  As the glass substrate according to the present invention, a glass substrate known to those skilled in the art can be used. The glass substrate to be used must be selected depending on the application, required performance, etc., for example, soda lime glass such as soda lime and white crown, low expansion glass such as borosilicate, alkali-free, aluminosilicate, synthetic quartz, etc. Glass etc. are mentioned.

  The glass substrate according to the present invention has at least one photosensitive halogenated emulsion layer, and an image is formed by the blackened silver formed in the silver halide emulsion layer by developing after exposure. The material that provides the exposure mask refers to the emulsion mask.

  The material that provides an exposure mask in which at least one light-shielding film on the glass substrate is composed of metallic chromium refers to the hard chromium mask.

  Chemical development by having at least one photosensitive silver halide emulsion layer on a glass substrate, having a physical development nucleus between the glass substrate and the silver halide emulsion layer, and developing after exposure. Silver is formed in the silver halide emulsion layer, and metallic silver is formed on the physical development nuclei by physical development in an unchemical development portion, and then the silver halide emulsion layer is removed and physical development is performed. The silver halide photosensitive material that leaves only the metallic silver image on the glass substrate refers to the DTR mask. The DTR mask forms a silver film on a glass substrate according to the principle of a silver complex diffusion transfer method (DTR method). The DTR method is the dissolution of unexposed silver halide as described in US Pat. No. 2,235,2014 or “Photographic Silver Halide Diffusion Processes”, Andre Rott, Edith Weyde, The Focal Press (1972). Then, it is converted into a soluble silver complex compound, which diffuses in the silver halide emulsion layer and is developed at the location of physical development nuclei to form a silver film. On the other hand, latent image nuclei are formed on the exposed silver halide by light irradiation, and are chemically developed in the emulsion layer. When this is washed with warm water after development, the silver halide photographic photosensitive layer containing water-soluble gelatin as the main binder is removed, and only the silver film formed on the physical development nuclei in the unexposed area remains on the glass substrate. , Form an image.

  In the exposure mask of the present invention, a protective layer is applied after image formation on the image forming surface of the emulsion mask, hard chrome mask or DTR mask. The thickness of the protective layer varies depending on the configuration and use of the exposure mask, but is preferably 5 μm or less, more preferably 3 μm or less in the dried state. If it exceeds 5 μm, problems such as a decrease in ultraviolet transmittance and a decrease in exposure resolution occur, and the amount of paint used increases, which is economically disadvantageous.

  In the present invention, the application of the protective layer coating to a desired image on the glass substrate means that the protective layer coating is provided only on the necessary portions without smearing the peripheral and back surfaces of the substrate with the coating. This not only improves workability in handling, but also suppresses the generation of dust, and the paint can be used efficiently without waste. For example, application starts from a certain scanning start point on the glass substrate surface, and the peripheral edge and the back surface of the substrate are soiled with paint by applying the desired image to the scanning end point on the glass substrate surface. The formation of the protective layer coating film in a desired image shape can be realized without any problem. As a scanning method, there are a raster scanning type in which the entire surface of the glass substrate is scanned and applied only to a desired image portion, and a vector scanning type in which only the desired image portion is applied.

  In the present invention, there are various scanning nozzle discharge type coating apparatuses depending on the viscosity, fluidity, and curing characteristics of the protective layer coating material. For example, a liquid metering discharge apparatus can be used. As such a liquid fixed quantity discharge apparatus, the thing made by Musashi Engineering Co., Ltd. is mentioned, It is preferable that it is a dispenser provided with the injection nozzle which ejects a liquid material. The types of dispensers include air dispensers, non-contact jet dispensers, high performance screw dispensers, mechanical high precision dispensers, tubing dispensers, and ultra-small quantity dispensers. The outline of the apparatus is described in detail in Japanese Patent No. 2749151, Japanese Patent No. 2772058, Japanese Patent No. 334241, and the like.

  In the present invention, a method for forming a film surface protective layer after image formation on an upper layer on the same side as the image forming layer with respect to the glass substrate will be described in detail.

  In a desired image form on the surface of the glass substrate, a liquid quantitative discharge device having a table displaceable in a horizontal plane on which the glass substrate is positioned and placed, and a liquid jet nozzle horizontally and vertically displaced with respect to the table. Paint is applied. In this case, the relative position of the table and the nozzle may be in accordance with a step-and-repeat method in which the nozzle moves while the table is stopped, or in accordance with a continuous movement method in which the table and the nozzle move together.

  The nozzle that discharges the protective layer paint is a precision discharge nozzle with an inner diameter of the order of several tens to several hundreds of micrometers, a taper type nozzle with high fluidity and high fluidity, and a single discharge. Can be selectively used according to the properties of the protective layer paint to be applied, such as a multi-type nozzle capable of performing multi-point discharge simultaneously.

  Examples of the liquid material applied using the liquid dispensing apparatus according to the present invention include various adhesives such as UV curable type, cyano type (instant type), anaerobic type, rubber type, epoxy type, hot melt type, alcohol, MEK, ammonia, thinner, solvent / volatile materials such as toluene, trichlene, acetone, freon, cream solder, flux, conductive adhesive (silver paste), urethane adhesive, junction coating resin, resist and other semiconductor / Liquid materials related to PCB mounting, various types of lubricants such as silicone oil, silicone grease, engine oil, motor oil, various resins such as UV resin, paraffin, wax, ink, dye, solvent-based paint, water-based paint, lacquer, enamel, etc. Various paints, various pastes for brazing (gold, silver, copper , And the like sealant. In particular, when using an ultra-small quantity dispenser, a low-viscosity liquid material such as alcohol, a volatile solvent, or a UV curable resin is applied. As the protective layer paint used in the present invention, a protective liquid for an exposure mask containing an organic-inorganic hybrid material described in Example 1-4 of JP-A-2003-14995, described in JP-A-2002-60736 A conductive polymer etc. can be mentioned.

  It is preferable that the glass substrate placed on a table displaceable in a horizontal plane is adsorbed and fixed to ensure high operational stability even during high-speed processing. In addition, it is desirable to adsorb and fix the glass substrate in order to correct warpage, swell, and the like.

  If the gap between the tip of the liquid jet nozzle and the glass substrate surface changes, uneven coating amount and uneven coating shape will occur, so in order to apply accurately and accurately, from the tip of the liquid jet nozzle to the glass substrate surface Based on the height sensor that measures the distance of the liquid and the means to control the vertical displacement of the liquid jet nozzle, the water head difference automatic correction function that corrects the discharge amount variation and realizes high-precision discharge, It is preferable to use a precise liquid dispensing device with a vacuum automatic control function for preventing air bubbles from entering and an automatic remaining amount warning function for preventing idling. The gap between the tip of the liquid jet nozzle and the surface of the glass substrate is preferably in the range of 10 to 300 μm, and more preferably in the range of 50 to 150 μm.

  When applying a protective layer coating for forming a film surface protective layer after image formation on an upper layer on the same side as the image forming layer with respect to the glass substrate, a program is created with a combination of drawing data, coordinate data, and application program data. Specifically, the control is performed by the application image pattern, the moving speed of the liquid jet nozzle, and the liquid discharge amount. The number of operation control axes is 3 axes including the Z axis for controlling the up-and-down displacement of the liquid ejection nozzle, assuming that the operation range of the table on which the glass substrate is placed and the operation range of the liquid ejection nozzle are the X-axis and Y-axis, respectively. Is preferred. By appropriately setting the coating image pattern using three axes, it is possible to apply the paint in a desired image shape without staining the peripheral edge and the back surface of the substrate with the protective layer paint. If the relative movement speed of the table on which the glass substrate is placed and the liquid jet nozzle is too large, liquid cracking will occur, and if it is too small, there is a possibility of causing unevenness in thickness and unevenness due to the difference in drying time. The speed range is preferably 10 to 200 mm / sec, and more preferably 50 to 100 mm / sec. The discharge amount of the liquid is determined by the discharge pressure and the discharge time, and is controlled by precise discharge in units of 0.01 mg and high-speed discharge with a cycle time of 0.1 sec or less.

  As described above, by forming the film surface protective layer on the upper layer of the exposure mask based on glass according to the present invention, the in-plane film can be obtained without staining the peripheral edge and the back surface of the glass substrate with the protective layer paint. It is possible to propose a method for forming a protective film for an exposure mask that has high thickness uniformity, is economical and has excellent workability, and achieves quality improvement.

  An emulsion mask, a hard chrome mask, and a DTR glass mask were used as the photomask master. Emulsion mask is a contact screen often used in the printing industry with a contact printer P-615-D made by Dainippon Screen Mfg. Co., Ltd. on an emulsion dry plate formed by forming a film surface of a photosensitive silver halide emulsion layer on a glass substrate. Through exposure, a mask for exposure (A) was obtained through development, fixing, washing and drying to produce a 60% flat screen image of 175 lines / inch (a uniform screen image having an area ratio of 60%).

  The hard chrome mask is prepared by applying an etching resist layer for laser exposure on chrome blanks formed by sputtering on the surface using quartz glass as a base material, prebaked, and then 175 with a HeCd laser (442 nm) drawing device on the chrome mask dry plate. Draw to create a 60% flat screen image of line / inch (uniform screen image with 60% area ratio), and then develop, post-bake, descum, chrome etching, resist stripping / cleaning, and drying mask (B) was obtained.

  The DTR mask is formed by forming a film surface of a photosensitive silver halide emulsion layer on a glass substrate, and forming a film surface having physical development nuclei between the glass substrate and the silver halide emulsion layer. 60% flat screen image of 175 lines / inch through a contact screen often used in the printing industry with Dainippon Screen Mfg. Co., Ltd.'s contact printer P-615-D (uniform screen image with an area ratio of 60%). The exposure mask (C) was obtained through development, washing with water and drying.

  Using an organic-inorganic hybrid material described in Example 1 of Japanese Patent Application Laid-Open No. 2001-64346, the above-described exposure masks (A) and (B) and ( C) It apply | coated on the image formation surface (size 200mm x 200mm, thickness 2.3mm), and it heated for 60 minutes at 100 degreeC, and obtained sample (D), (E), and (F), respectively.

  The liquid jet nozzle diameter was 180 μm, and the gap between the nozzle tip and the glass substrate surface was finely adjusted to 50 μm. The scanning start point of application is set at a position 3 mm from the edge of the glass substrate, the spray nozzle is reciprocated at 190 mm at a pitch of 100 mm / sec, and the table on which the glass substrate is placed is Each time the spray nozzle was reciprocated, it was transported at a pitch of 2.0 mm in a direction perpendicular to the direction of movement of the spray nozzle, and the coating was discharged at a discharge pressure of 25 kPa and a discharge time of 20 ms to start application. The scanning end point was set at a position 3 mm from the edge of the glass substrate opposite to the scanning start point, and the discharge of the paint was stopped as soon as the end point was reached. Further, when the exposure mask was fixed to the printed circuit board exposure apparatus, it was applied without discharging the paint to the portion (5 mm × 5 mm area from the edge end) in contact with the fixing jig. As a result, a good coating film having no step unevenness and thickness unevenness was obtained in an area of 2 mm from the edge end except for the contact portion with the fixing jig. Moreover, there was no stain | pollution | contamination of the glass base-material peripheral part and back surface by a protective layer coating, and the uniform protective layer coating film was formed in the surface. A detailed coating pattern is shown in FIG.

  When the adhesion was evaluated on the image forming surfaces of the mask samples for exposure (D), (E), and (F) in accordance with the cross-cut method of JIS-K5400, no peeling of the film was observed. Moreover, although the exfoliation mask sample (B) showed no peeling of the coating film, the exposure mask samples (A) and (C) showed peeling of the coating film.

  In the same manner as in Example 1, using the high-speed processing / high-precision desktop robot manufactured by Musashi Engineering Co., Ltd., the conductive polymer described in JP-A-2002-60736 was applied to the exposure masks (A) and (B ) And (C) (size 200 mm × 200 mm, thickness 2.3 mm), and heated at 150 ° C. for 15 minutes to obtain samples (G), (H), and (I), respectively. It was. As a result, a good film surface without step unevenness and thickness unevenness was obtained in the same manner as in Example 1, and a uniform protective layer coating film was formed in the surface without contamination of the periphery and back surface of the glass substrate by the protective layer paint. It was done.

  The liquid jet nozzle diameter was 180 μm, and the gap between the nozzle tip and the glass substrate surface was finely adjusted to 50 μm. The scanning start point of application is set at a position 3 mm from the edge of the glass substrate, the spray nozzle is reciprocated at 190 mm at a pitch of 100 mm / sec, and the table on which the glass substrate is placed is Each time the spray nozzle was reciprocated, it was transported at a pitch of 2.0 mm in a direction perpendicular to the direction of movement of the spray nozzle, and the coating was discharged at a discharge pressure of 25 kPa and a discharge time of 20 ms to start application. The scanning end point was set at a position 3 mm from the edge of the glass substrate opposite to the scanning start point, and the discharge of the paint was stopped as soon as the end point was reached. Further, when the exposure mask is fixed to the printed circuit board exposure apparatus, the paint is not discharged to a portion (5 mm × 5 mm area from the edge end portion) in contact with the fixing jig. In order to prevent electrostatic charging, a ground wire was applied linearly between a conductive image portion and a non-conductive peripheral portion. As a result, a good coating film with no step unevenness or thickness unevenness was obtained in a region 2 mm from the edge end except for the contact portion with the fixing jig and the ground wire. Moreover, there was no stain | pollution | contamination of the glass base-material peripheral part and back surface by a coating material, and the uniform coating film was formed in the surface. A detailed coating pattern is shown in FIG.

  When the adhesiveness of the exposure mask samples (G), (H), and (I) was evaluated according to the grid pattern method of JIS-K5400, no peeling of the film was observed.

  Proposal of a method for forming a protective mask mask for exposure masks that achieves high quality, high in-plane film thickness uniformity, economic efficiency, and workability without polluting the peripheral edge and back surface of the substrate. can do.

Application pattern Application pattern

Explanation of symbols

1 Scanning start point 2 Jig contact area 3 Scanning end point 4 Ground wire 5 Mask for exposure

Claims (5)

A method for forming a protective film on a mask for exposure using a glass as a base material, wherein a protective layer paint is applied in a desired image form on the base material. . The method for forming a protective layer coating film according to claim 1, wherein the protective layer coating is applied by a scanning nozzle discharge method. The exposure mask has at least one photosensitive halogenated emulsion layer on a glass substrate, and an image is formed by the blackened silver formed in the silver halide emulsion layer by developing after exposure. The method for forming a protective layer coating film according to claim 1 or 2, wherein the mask is for exposure. The method for forming a protective layer coating film according to claim 1 or 2, wherein the exposure mask is an exposure mask in which at least one of the light-shielding films on the glass substrate is composed of metallic chromium. The exposure mask has at least one photosensitive silver halide emulsion layer on a glass substrate, has a physical development nucleus between the silver halide emulsion layers, and is chemically developed by developing after exposure. An exposure mask prepared by forming silver on the physical development nuclei and then removing the silver halide emulsion layer to leave only a metallic silver image formed by physical development on a glass substrate. Item 3. A method for forming a protective coating film according to Item 1 or 2.

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