JP5198809B2 - Entry sheet for drilling - Google Patents

Description

  The present invention relates to an entry sheet for drilling used in the field of printed wiring board materials.

  As a drilling method for copper-clad laminates used for printed wiring board materials, a method is generally used in which drilling is performed by stacking copper-clad laminates and placing aluminum foil or the like on top of them. It has been adopted. In recent years, with the demand for improved reliability and increased density of printed wiring board materials, high-quality drilling has been required, such as improved hole location accuracy and reduced hole wall roughness. Therefore, a drilling method using a polyethylene glycol sheet (see, for example, Patent Document 1), a lubricant sheet for drilling in which a water-soluble resin layer is formed on a metal foil (see, for example, Patent Document 2), a thermosetting resin thin film An entry sheet for drilling (see, for example, Patent Document 3) in which a water-soluble resin layer is formed on an aluminum foil formed with a metal foil has been proposed and put to practical use. In recent years, the phenomenon that the resin component used in each sheet wraps around the drill bit has increased with the miniaturization of the wiring pattern and the reduction of the through-hole diameter to reduce the size and weight of the printed wiring board. In particular, when drilling a small diameter of 0.1 mmφ or less, breakage of the drill bit may be observed, and further improvement is necessary.

JP-A-4-92488 JP-A-5-169400 JP 2003-136485 A

  The present invention provides an entry sheet for drilling that suppresses wrapping of a resin around a drill bit, thereby reducing breakage of the drill bit and excellent hole position accuracy.

  As a result of various studies to solve the above problems, the present inventors have added a specific water-soluble substance (b) and a water-soluble lubricant (c) to the water-soluble resin (a). The inventors have found that the wrapping property of the resin component around the drill bit is suppressed, and as a result, breakage of the drill bit is suppressed, and the present invention has been completed. That is, the present invention provides a sheet-like base material with one or more selected from the group consisting of a water-soluble resin (a), a polyhydric alcohol, an amino acid derivative alcohol, an organic acid and an organic salt. An entry sheet for drilling in which a resin composition layer containing a water-soluble substance (b) and a water-soluble lubricant (c) is formed.

According to the present invention, an entry sheet for drilling with less resin winding around a drill bit can be obtained. By suppressing the resin wrapping, the hole position accuracy is further improved when drilling is performed under the same conditions. Further, breakage of the drill bit caused by the resin winding can be suppressed, and the production efficiency of the drilling process can be remarkably improved.

  The water-soluble resin (a) used in the present invention is polyethylene oxide, polypropylene oxide, polyacrylic acid soda, polyacrylamide, polyvinyl pyrrolidone, carboxymethyl cellulose, polytetramethylene glycol, polyether ester having an average molecular weight of 10,000 or more. Polyvinyl alcohol is exemplified, and one kind or two or more kinds may be appropriately mixed and used.

  The polyether ester which is one kind of the water-soluble resin (a) used in the present invention is not particularly limited as long as it is an esterified product of polyalkylene oxide. Typical examples include polyethylene glycol, polyethylene oxide, polypropylene glycol, polytetramethylene glycol, glycols exemplified by polypropylene oxide and copolymers thereof, or polymers of ethylene oxide, and phthalic acid, isophthalic acid. Terephthalic acid, sebacic acid, and the like, and dimethyl esters, diethyl esters and the like, polymellitic carboxylic acids exemplified by pyromellitic acid anhydride, the anhydrides, or resins obtained by reacting the esters, etc. It is also possible to use one kind or a mixture of two or more kinds as appropriate.

  The water-soluble substance (b) used in the present invention is not particularly limited as long as it is a water-soluble substance selected from the group consisting of polyhydric alcohols, amino acid derivative alcohols, organic acids and organic salts, It is also possible to use one kind or a mixture of two or more kinds as appropriate. Preferred as these water-soluble substances (b) are trimethylolpropane, pentaerythritol, sorbitol, xylitol, inositol as polyhydric alcohols, glycinol, phenylalaninol as amino acid derivative alcohols, and organic acids. Are malic acid, succinic acid, fumaric acid, maleic acid, formic acid, acetic acid, propionic acid, stearic acid and the like, and examples of organic salts include metal salts of the organic acids mentioned above. The blending amount of the water-soluble substance (b) is 0.1 to 5% by weight, preferably 0.2 to 3% by weight of the total of the water-soluble resin (a) and the water-soluble lubricant (c).

  The water-soluble lubricant (c) in the present invention means polyethylene glycol, polypropylene glycol having an average molecular weight of less than 10,000; polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonyl Polyoxyethylene monoethers exemplified by phenyl ether, polyoxyethylene octylphenyl ether, etc .; polyoxyethylene monostearate, polyoxyethylene sorbitan monostearate; hexaglycerin monostearate, decahexaglycerin monostearate, etc. And polyglycerin monostearates, including polyoxyethylene propylene copolymers and derivatives thereof, 1 type or 2 types It is also possible to use a mixture of the above as appropriate. The amount of the water-soluble lubricant (c) is 10 to 90 parts by weight, more preferably 20 to 80 parts by weight, based on 100 parts by weight of the total amount of the water-soluble resin (a) and the water-soluble lubricant (c). It is. If the water-soluble lubricant (c) is less than 10 parts by weight, the viscosity tends to be too high, and problems are likely to occur in lubricity when drilling, and if it exceeds 90 parts by weight, the resin layer becomes brittle.

  The resin composition used in the present invention comprises the water-soluble resin (a), the water-soluble substance (b) and the water-soluble lubricant (c) as essential components, and the mixing method is used industrially. Any known method may be used without any particular limitation. Specifically, the resin composition is rolled or kneaded, or other kneading means, and is appropriately heated or heated to obtain a uniform mixture, or, if necessary, a solvent containing water. Examples thereof include a method of dissolving or dispersing into a resin composition solution.

  The sheet-like substrate used in the present invention is not particularly limited as long as it is a known sheet-like substrate such as a metal foil or an organic film / sheet, but an aluminum foil is preferable. As the material of the aluminum foil, aluminum having a purity of 95% or more is preferable, and specifically, 5052, 3004, 3003, 1N30, 1050, 1070, 1085, etc. defined in JIS-H4160 are exemplified. More than 99.3% aluminum is more preferable. By using high-purity aluminum foil for the base material, the impact and biting of the drill bit are alleviated and combined with the effect of reducing the heat generated by the frictional heat of the drill bit due to the resin composition, Position accuracy and hole quality can be greatly improved. The thickness of the substrate is preferably in the range of 50 to 500 μm. If the thickness is less than 50 μm, burrs are likely to occur in the laminated plate after drilling, and if it exceeds 500 μm, it becomes difficult to discharge the generated chips. In addition, the use of an aluminum foil in which an adhesive film having a thickness of 0.1 to 10 μm is previously formed on these aluminum foils is most preferable from the viewpoint of adhesion to the resin composition. Examples of the adhesive used for the adhesive film include urethane-based, vinyl acetate-based, vinyl chloride-based, polyester-based and copolymers thereof, and epoxy-based and cyanate-based adhesives.

  In the present invention, as a method for forming the resin composition layer on the sheet-like base material, for example, the resin composition is appropriately heated and melted or applied to the sheet-like base material as a liquid dissolved or dispersed in a solvent. The method of forming a resin composition layer, or after forming a resin composition layer (sheet) in advance, the resin composition layer (sheet) is overlaid on at least one side of the sheet-like substrate and heated with a roll or the like. There is a method of bonding with an adhesive or the like. The method for producing the resin composition layer (sheet) is not particularly limited as long as it is a known method used industrially. Specifically, the resin composition is appropriately heated and melted and mixed using a roll, kneader, or other kneading means, and a resin composition layer is formed on the release film by a roll method or a curtain coat method. And a method of forming a resin composition into a resin composition sheet having a desired thickness in advance using a roll, a T-die extruder, or the like.

  The method for forming a resin composition solution in which a resin composition is dissolved or dispersed in a solvent containing water on a sheet-like substrate is not particularly limited as long as it is a known method used industrially. Specifically, a method of forming a coating layer of the resin composition solution on a substrate using a knife coater or a die coater and evaporating the solvent by hot air drying in a drying furnace is exemplified. The method for drying the sheet-like substrate on which the coating layer is formed and forming the resin composition layer on the substrate is not particularly limited as long as it is a known method used industrially. Specifically, hot air drying is often used, but a method of using infrared rays, microwaves, and high-frequency heating in combination as necessary is exemplified. The drying conditions depend on the size / capacity of the dryer, the desired resin composition layer thickness, the coating speed, etc., for example, when the drying zone is divided into three locations, The temperature is gradually raised from the entrance side to 60 ° C, 90 ° C, 120 ° C so that the difference between the temperature of the substrate and the substrate temperature at that time does not become too large, and finally the substrate temperature becomes 100 ° C or higher Such conditions are exemplified.

  In the present invention, the thickness of the resin composition layer formed on the sheet-like substrate is preferably in the range of 5 to 200 μm. If the resin composition layer thickness is less than 5 μm, the hole quality obtained due to insufficient lubrication performance will deteriorate, and if it exceeds 200 μm, the wrapping phenomenon of the resin component around the drill bit will not be improved when drilling with a small diameter, and the hole position will not be improved. Accuracy deteriorates. As described above, the entry sheet for drilling according to the present invention is obtained.

The entry sheet for drilling according to the present invention is at least the most preferable one in which one or a plurality of printed wiring materials are stacked when drilling a printed wiring material, for example, a copper-clad laminate or a multilayer copper-clad laminate. It arrange | positions on an upper surface so that a printed wiring material may be touched, and drills a hole from the resin composition layer surface side of the entry sheet for drilling. Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Example 1)
Polyethylene glycol dimethyl terephthalate polycondensate (trade name: Paogen PP-15, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 50 parts by weight, polyoxyethylene monostearate (trade name: Nonion S-40, manufactured by NOF Corporation) 50 parts by weight and 2 parts by weight of xylitol were kneaded in a nitrogen atmosphere at a temperature of 150 ° C. and then extruded onto a PET film using a T-die extruder to obtain a resin sheet having a thickness of 100 μm. Obtained. This resin sheet is a dielectric heating roll set at a temperature of 100 ° C on one side of a 100 µm thick aluminum foil (material: 1070) coated with 5 µm thick polyester adhesive (trade name: R820, manufactured by Cemedine Co., Ltd.) in advance. And a pressure roll to obtain an entry sheet for drilling with a total thickness of 200 μm. Place the resulting drill hole entry sheet on the top surface of two stacked 0.4mm thick, double-sided 12μm copper clad laminates (trade name: HL832 0.4T / T, manufactured by Mitsubishi Gas Chemical Co., Ltd.) A hitting plate (paper phenol laminate) is placed on the drill bit: 0.15 mmφ (trade name: NEUL004S, manufactured by Union Tool Co., Ltd.), rotation speed: 150000 rpm, feed speed: 12 μm / rev. Table 1 shows the results of drilling and hole evaluation.

(Example 2)
Polyethylene glycol dimethyl terephthalate polycondensate (trade name: Paogen PP-15, Daiichi Kogyo Seiyaku Co., Ltd.) 30 parts by weight, polyoxyethylene monostearate (trade name: Nonion S-40, manufactured by NOF Corporation) 70 parts by weight and 0.5 parts by weight of succinic acid were kneaded in a nitrogen atmosphere at a temperature of 150 ° C using a kneader, then extruded onto a PET film using a T-die extruder, and a resin sheet with a thickness of 60 µm Got. This resin sheet is a dielectric heating roll set at a temperature of 100 ° C on one side of a 70 µm thick aluminum foil (material: 1N30) coated with a polyester adhesive (trade name: R820, manufactured by Cemedine Co., Ltd.) 5 µm thick. And a pressure roll to obtain an entry sheet for drilling with a total thickness of 130 μm. Place the resulting drill hole entry sheet on the top surface of two stacked 0.4mm thick, double-sided 12μm copper clad laminates (trade name: HL832 0.4T / T, manufactured by Mitsubishi Gas Chemical Co., Ltd.) Place a contact plate (paper phenol laminate) on the drill bit, drill bit: 0.12mmφ (Product name: MD J531C Union Tool Co., Ltd.), rotation speed: 150000rpm, feed rate: 12μm / rev. Table 2 shows the results of drilling and hole evaluation.

Example 3
Polyethylene glycol / dimethyl terephthalate polycondensate (Paogen PP-15) 40 parts by weight and polyoxyethylene monostearate (Nonion S-40) 60 parts by weight were dissolved in 180 parts by weight of water in a stirring tank, and then isopropyl alcohol was added. Adding 80 parts by weight, a resin solution having a solid content of 27.8% and a viscosity of 14,000 centipoise (25 ° C.) was obtained. To this aqueous solution, 1 part of glycinol and 1 part of inositol were added. This resin solution is applied on a single side of 100μm aluminum foil (material: 1085) with 5μm thick polyester adhesive (R820) using a die coater. In a drying oven (set temperature: 60-100-140 ° C) under conditions where hot air is blown onto the top surface at a wind speed of 20 m / min. A sheet was obtained. Table 3 shows the results of drilling and hole evaluation performed in the same manner as in Example 1 using the obtained drilling entry sheet.

Example 4
Polyethylene glycol / dimethyl terephthalate polycondensate (Paogen PP-15) 20 parts by weight, polyethylene glycol (trade name: PEG 20000, manufactured by Sanyo Chemical Co., Ltd.) 20 parts by weight polyoxyethylene monostearate (Nonion S-40) 60 parts by weight After being dissolved in 280 parts by weight of water in a stirring tank, 40 parts by weight of isopropyl alcohol was added to obtain a resin solution having a solid content of 23.8% and a viscosity of 7000 centipoise (25 ° C.). To this resin solution, 0.5 part of sodium formate and 1 part of pentaerythritol were further mixed. This resin solution is applied to one side of 70μm aluminum foil (1070) using a die coater in a thickness of 43μm, in a roll support type drying oven (set temperature: 60-90-120 ℃) with a furnace length of 3m x 3 chambers. Was passed at 0.07 m / sec under conditions where hot air was blown onto the top surface at a wind speed of 15 m / min to obtain an entry sheet for drilling with a total thickness of 80 μm. The resulting drill hole entry sheet is placed on the top surface where four sheets of copper-clad laminate (product name: HL832 0.2T / T, manufactured by Mitsubishi Gas Chemical Co., Inc.) with a thickness of 0.2mm and double-sided are placed on the bottom surface. And a drill bit: 0.105 mmφ (trade name: MDJ492B, manufactured by Union Tool Co., Ltd.), rotation speed: 160000 rpm, feed rate: 5 μm / rev. Table 4 shows the results of the drilling of 3,000 hits under the above conditions and the hole evaluation.

(Comparative Example 1)
Polyethylene glycol dimethyl terephthalate polycondensate (trade name: Paogen PP-15, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 50 parts by weight, polyoxyethylene monostearate (trade name: Nonion S-40, manufactured by NOF Corporation) 50 parts by weight was kneaded in a nitrogen atmosphere at a temperature of 150 ° C. using a kneader, and then extruded onto a PET film using a T-die extruder or the like to obtain a resin sheet having a thickness of 100 μm. This resin sheet is a dielectric heating roll set at a temperature of 100 ° C on one side of a 100 µm thick aluminum foil (material: 1070) coated with 5 µm thick polyester adhesive (trade name: R820, manufactured by Cemedine Co., Ltd.) in advance. And a pressure roll to obtain an entry sheet for drilling with a total thickness of 200 μm. Table 1 shows the results of drilling the drilling entry sheet under the same conditions as in Example 1 and evaluating the holes.

(Comparative Example 2)
Polyethylene glycol dimethyl terephthalate polycondensate (trade name: Paogen PP-15, Daiichi Kogyo Seiyaku Co., Ltd.) 30 parts by weight, polyoxyethylene monostearate (trade name: Nonion S-40, manufactured by NOF Corporation) 70 parts by weight was kneaded in a nitrogen atmosphere at a temperature of 150 ° C. using a kneader, and then extruded onto a PET film using a T-die extruder or the like to obtain a resin sheet having a thickness of 60 μm. This resin sheet is a dielectric heating roll set at a temperature of 100 ° C. on one side of a 70 μm thick aluminum foil (material: 1N30) coated with a polyester adhesive (trade name: R820, manufactured by Cemedine Co., Ltd.) in a thickness of 5 μm. And a pressure roll to obtain an entry sheet for drilling with a total thickness of 130 μm. Table 2 shows the result of drilling the drilling entry sheet under the same conditions as in Example 1 and evaluating the holes.

(Comparative Example 3)
Polyethylene glycol / dimethyl terephthalate polycondensate (Paogen PP-15) 40 parts by weight and polyoxyethylene monostearate (Nonion S-40) 60 parts by weight were dissolved in 180 parts by weight of water in a stirring tank, and then isopropyl alcohol was added. Adding 80 parts by weight, a resin solution having a solid content of 27.8% and a viscosity of 14,000 centipoise (25 ° C.) was obtained. This resin solution is applied on a single side of 100μm aluminum foil (material: 1085) with 5μm thick polyester adhesive (R820) using a die coater. In a drying oven (set temperature: 60-100-140 ° C) under conditions where hot air is blown onto the top surface at a wind speed of 20 m / min. A sheet was obtained. Table 3 shows the results of drilling the drilling entry sheet under the same conditions as in Example 3 and evaluating the holes.

(Comparative Example 4)
Polyethylene glycol / dimethyl terephthalate polycondensate (Paogen PP-15) 20 parts by weight, polyethylene glycol (trade name: PEG 20000, manufactured by Sanyo Chemical Co., Ltd.) 20 parts by weight, polyoxyethylene monostearate (Nonion S-40) 60 parts by weight A part was dissolved in 280 parts by weight of water in a stirring tank, and then 40 parts by weight of isopropyl alcohol was added to obtain a resin solution having a solid content of 23.8% and a viscosity of 7000 centipoise (25 ° C.). This resin solution is applied to one side of 70μm aluminum foil (1070) using a die coater in a thickness of 43μm, in a roll support type drying oven (set temperature: 60-90-120 ℃) with a furnace length of 3m x 3 chambers. Was passed at 0.07 m / sec under conditions where hot air was blown onto the top surface at a wind speed of 15 m / min to obtain an entry sheet for drilling with a total thickness of 80 μm. Table 4 shows the results of drilling the drilling entry sheet under the same conditions as in Example 4 and evaluating the holes.

(Method of hole evaluation)
The evaluation was based on visual observation of the hole position accuracy when drilling and the amount of resin wound around the drill bit.
・ Hole position accuracy: Measure the deviation from the command coordinates for the position of 2 bits × 3000 holes / piece = 6000 holes, which are bright on the back side of the bottom plate of the stacked copper clad laminate, Standard deviation and maximum value were determined. This operation was repeated three times.

Claims (4)

A group consisting of one or more water-soluble resins (a) selected from the group consisting of polyethylene glycol / dimethyl terephthalate polycondensate and polyethylene glycol , and glycinol, organic acids and organic salts on a sheet-like substrate An entry sheet for drilling, in which a resin composition layer containing one or more water-soluble substances (b) selected from the above and a water-soluble lubricant (c) that is polyoxyethylene monostearate is formed.   The entry sheet for drilling according to claim 1, wherein the resin composition layer has a thickness of 5 to 200 µm.   The entry sheet for drilling according to claim 1 or 2, wherein the sheet-like substrate is an aluminum foil. The entry sheet for drilling according to claim 3, wherein the aluminum foil is an aluminum foil in which an adhesive film having a thickness of 0.1 to 10 µm is formed in advance.