JP2005159116A - Method for manufacturing printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a printed wiring board using a sheet for punching a printed wiring board for highly precisely carrying out the punching of the printed wiring board, and for obtaining a high quality printed wiring board by minimizing the wobbling of a drill bit, and reducing drill smear or internal wall roughness. <P>SOLUTION: This sheet for punching a printed wiring board in which adhesive added with lubricant is interposed by thermoplastic resin films is inserted between a printed wiring board and a backup board to carry out the punching of the printed wiring board. In this case, it is desired that the punching of the printed wiring board is carried out from the upper part with such configurations that aluminum foils are laminated on the uppermost part of the printed wiring board. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printed wiring board manufacturing method using a printed wiring board drilling sheet.

  In recent years, with the spread of personal computers and mobile phones, electronic products are required to be smaller, lighter, and more functional. Along with this, the density of printed wiring boards and the increase in the number of layers are rapidly progressing. As a result, the line width and spacing of printed wiring boards are narrowed, and the number of through-holes increases as the diameter of through-holes increases. doing. In addition to that, high precision is inevitably required for the hole positions for connection. In the future, the pattern density and the number of layers will continue to increase further, and the number of drilling operations with drills and smaller diameters are expected to increase.

In order to perform such a small-diameter drilling process, drilling is generally performed by stacking a processing sheet on a printed wiring board, so that the accuracy of the hole position processed in the wiring board is improved and the inner wall of the hole is improved. It is known that drilling can be performed accurately with reduced roughness.
As a processing sheet used here, a method of drilling using a thermoplastic film (Patent Document 1), a method of drilling a printed wiring board using a sheet in which both sides of an aluminum foil are sandwiched by paper (Patent Document) 2) Small-diameter drilling such as a method using a sheet obtained by bonding an aluminum foil with an adhesive (Patent Document 3) or a method using a sheet made of a water-soluble resin and a water-soluble lubricant on an aluminum foil (Patent Document 4) Processing sheets have been proposed.

However, in the method of drilling using the thermoplastic film described in Patent Document 1, the hole position accuracy is deteriorated when the multilayer board wiring board is punched. The method of drilling a printed wiring board using a sheet in which both sides of an aluminum foil described in Patent Document 2 are sandwiched with paper is highly likely to generate paper powder and adversely affect subsequent processes. In the method using the sheet in which the aluminum foil described in (2) is bonded with an adhesive, it cannot be denied that the cost increases because two aluminum foils are bonded.
Further, in the method using a sheet comprising a film formed from a water-soluble resin and a water-soluble lubricant on the aluminum foil described in Patent Document 4, humidity control is required because the sheet is composed of a water-soluble resin and a water-soluble lubricant. Furthermore, since the melting point is close to room temperature, there is a problem that temperature management is required.

Japanese Patent Publication No. 7-50831 Japanese Patent Laid-Open No. 62-214000 Japanese Patent Laid-Open No. 11-48196 JP-A-10-335780

The present invention has been made in view of such a situation, and provides a method for manufacturing a printed wiring board using a printed wiring board drilling sheet capable of accurately drilling a printed wiring board.
The present invention also provides a method of manufacturing a printed wiring board using a printed wiring board drilling sheet that can obtain a high-quality printed wiring board by reducing drill smear and inner wall roughness with less axial deflection of the drill. To do.

The present invention relates to the following.
1. A printed wiring board drilling sheet in which an adhesive containing a lubricant is sandwiched between thermoplastic resin films is inserted between the printed wiring board and a backup board, and the printed wiring board is punched. Manufacturing method of printed wiring board.
2. Item 2. The method for producing a printed wiring board according to item 1, wherein the aluminum foil is laminated on the uppermost part of the printed wiring board, and drilling is performed from above with a drill.

  The printed wiring board manufacturing method using the processing sheet according to the present invention is used for drilling a printed wiring board that requires high-precision drilling, does not generate smear, has high hole position accuracy, and further has a hole wall roughness. Can be obtained. In addition, it has the effect of preventing damage to the drill and extending its life.

A method for manufacturing a printed wiring board using the printed wiring board drilling sheet according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing an example of a method for producing a printed wiring board using a printed wiring board drilling sheet 1 according to the present invention. FIG. 2 shows a cross-sectional view of an example of the printed wiring board processed sheet 1 used in the present invention. The thermoplastic resin film 2 is bonded through an adhesive 3 to which a lubricant is added. In FIG. 1, a printed wiring board drilling sheet 1 is disposed between a printed wiring board 4 and a backup board 5, and an aluminum foil 6 is stacked on the top of the substrate, and drilling is performed from above the aluminum foil 6 with a drill 7. .
Lubricant between the substrate and aluminum foil chips that cause roughening of the inner wall of the hole is more effective than using a drilling sheet with lubricant on a conventional aluminum foil Improves inner wall roughness by encouraging discharge. Furthermore, it was found that the position where the printed wiring board punching sheet is sandwiched is optimal for obtaining a high-quality printed wiring board between the stacked printed wiring boards and the backup board below.

  Examples of the material of the thermoplastic resin film 2 used in the present invention include polyethylene, polypropylene, polyethylene-polypropylene blend polymer, polyvinyl alcohol, polyamide, polyvinyl chloride, polyethylene terephthalate, polycarbonate, EVA and the like, and a melting point of 90 to 250. C. is preferred. When the melting point is low, the fusion to the drill tends to become remarkable, and when the melting point is high, the film formation tends to be difficult.

The thermoplastic resin film 2 in the present invention may be a single layer or a multilayer film having two or more layers.
The thickness of the thermoplastic resin film 2 in the present invention is preferably 12 to 150 μm. If the thermoplastic resin film is too thin, wrinkles are likely to occur at the time of producing the sheet, and if it is too thick, the thickness accuracy is impaired and the drilling accuracy tends to be lowered.

  As the pressure-sensitive adhesive 3 to which a lubricant is added, a polymer or copolymer of a methacrylic ester such as acrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate or the like generally represented by butyl acrylate, ethyl acrylate or butyl methacrylate Acrylic adhesive, natural rubber adhesive such as isoprene, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, styrene-ethylene-butadiene copolymer rubber, synthetic rubber adhesive such as polyisobutylene Agents, ethylene-vinyl acetate copolymer adhesives, and mixed adhesives thereof can be used.

Lubricants mixed with the adhesive include ester-based synthetic oils such as glycerin fatty acid esters, diphenyl ether-based synthetic oils, silicone-based synthetic oils, mineral oils, and solid paraffin, polyethylene wax, molybdenum disulfide, boron nitride, and the like. Although a lubricant etc. are mentioned, it is not limited to this, These lubricants may be used individually or in mixture. The amount of the lubricant used is preferably 5 to 70 parts by weight, more preferably 15 to 60 parts by weight with respect to 100 parts by weight of the adhesive. If the addition amount of the lubricant is too small, the effect of promoting the sliding of the drill is lowered, and if it is too much, the anchoring property with the thermoplastic resin film is lost and peeled off.
Further, by mixing the synthetic oil-based lubricant and the solid lubricant, an effect of facilitating film formation of the pressure-sensitive adhesive added with the lubricant can be obtained.

  The thickness of the pressure-sensitive adhesive 3 to which a lubricant is added is preferably 10 to 100 μm. If it is thinner than 10 μm, the lubricating effect is insufficient and the inner wall roughness tends to increase. On the contrary, if it is thicker than 100 μm, chip discharge is hindered and the inner wall roughness is increased, and the wear of the drill tends to be accelerated.

  Here, as a procedure for producing the punched sheet 1, the viscosity of the adhesive added with the lubricant is adjusted with an organic solvent, and the adhesive added with the lubricant is formed on the thin film by means of coating or the like. Although the method of laminating the thin film is generally mentioned, it is not limited to this.

  The target printed wiring board is not particularly limited, but is typically a multilayer board having two or more layers, which is used to process through holes. The drill to be used is particularly suitable for drilling a small-diameter hole having a diameter of 0.1 to 1.0 mm, which has a high rotation and a large load on the drill.

  When drilling using such a punched sheet, it was found that the drilling workability is affected by the insertion position of the drilled sheet. As a result of various investigations, the hole punching sheet has better drilling performance when inserted between the printed wiring board and the backup board than when inserted between the upper part of the printed wiring board or the printed wiring board. I found out. When inserting a punching sheet between printed wiring boards, the effect of discharging chips from the backup board cannot be obtained sufficiently, and clogging tends to occur. Further, it is desirable to perform a drilling process from above with a drill in a configuration in which an aluminum foil is laminated on the uppermost part of the printed wiring board as a punching plate. The thickness of the aluminum foil used as the backing plate in this case is preferably 50 to 200 μm. When the thickness of the aluminum foil is less than 50 μm, the effect of suppressing the shake of the drill is lowered, and the hole position accuracy is deteriorated accordingly. Moreover, when thicker than 200 micrometers, there exists a tendency to promote wear of a drill.

EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.
(Example 1)
Adhesion obtained by adding 20 parts by weight of lubricating oil Neocool FL-1 (trade name, manufactured by Matsumura Oil Research) to 100 parts by weight of SEBS adhesive G-1657 (trade name, manufactured by Shell Chemical Co., Ltd.) on a polypropylene film having a thickness of 40 μm The agent was dissolved in toluene, applied to a coating amount of 20 μm, and pasted with another polypropylene film to form a punching sheet.
The punched sheet was inserted between a stack of three copper-clad laminates of 6 layers and a paper phenol plate, and aluminum having a thickness of 150 μm was laminated on the top. Using a φ0.3 mm drill, drilling 3000 holes under the conditions of 125 krpm, 2.5 m / min, 20 μ / rev, and whether there is smear in the uppermost multilayer plate hole for 20 holes of 2981-3000 shots, The hole position accuracy and hole wall roughness were observed. The results are shown in Table 1.

(Example 2)
Other than adding 100 parts by weight of SEBS adhesive G-1657 (trade name, manufactured by Shell Chemical Co., Ltd.) 20 parts by weight of lubricating oil Neocool FL-1 (trade name, manufactured by Matsumura Oil Research) and 5 parts by weight of boron nitride Were tested as in Example 1. The results are shown in Table 1.

(Example 3)
A thermoplastic film is a three-layer extruded film whose outer layer is polypropylene show aroma FA-465 (trade name, manufactured by Showa Denko KK), and whose inner layer is polyethylene sholex S6005A (trade name, manufactured by Showa Denko KK). The test was performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
Three layers of six-layer copper-clad laminates were laminated with 150 μm thick aluminum at the top, and only the paper phenol plate was installed at the bottom without inserting a perforated sheet. It tested on the same conditions. The results are shown in Table 1.

(Comparative Example 2)
A punched sheet produced by the same method as in Example 1 was inserted between the first and second layers of three layers of six copper-clad laminates, and an aluminum foil with a thickness of 150 μm was laminated on the top. A paper phenol plate was installed at the bottom, and the others were tested under the same conditions as in Example 1. The results are shown in Table 1.

  In Examples 1 and 2, smear was not generated, and the hole position accuracy, hole wall roughness, and hole clogging were good. On the other hand, in Comparative Example 1, since there was no lubricant, the lubrication effect was reduced, the hole wall was rough, and clogging occurred. In Comparative Example 2, clogging occurred.

The schematic sectional drawing which shows the printed wiring board manufacturing method using the printed wiring board punching sheet. Sectional drawing of the sheet | seat for printed wiring board drilling processing concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet for printed wiring board drilling process 2 Thermoplastic resin film 3 Lubricant containing adhesive 4 Printed wiring board 5 Aluminum foil 6 Backup board 7 Drill

Claims (2)

Printed circuit board drilling process by inserting a printed wiring board drilling sheet with a lubricant-added adhesive between thermoplastic resin films and inserting it between the printed wiring board and backup board A method for manufacturing a wiring board. The manufacturing method of the printed wiring board of Claim 1 which drills with a drill from the upper direction in the structure which laminated | stacked the aluminum foil on the uppermost part of the printed wiring board.

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