JP3976228B2 - Printed circuit board punching sheet and printed circuit board punching method using such a sheet - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printed wiring board punching sheet useful for drilling (piercing) processing for forming a through hole in a printed wiring board, and a printed wiring board punching method using such a sheet.
[0002]
[Prior art]
When drilling through-holes in a printed circuit board, if the hole diameter is large, the hole is drilled directly on the board. In general-purpose substrates with small hole diameters, a metal thin film such as an aluminum foil is generally formed on the substrate. And various water-soluble compound layers are arranged and penetrated using a drill, a cone, a puncher or the like.
In the above method, the use of the water-soluble compound layer prevents the drill bit from escaping due to the unevenness of the substrate surface and accurately sets the drill tip at the position of the desired through-hole, that is, the processing position. Aluminum foil is used for the purpose of ensuring accuracy. Furthermore, the use of aluminum foil prevents the peeling of the copper surface on the board when the drill is pulled out, and prevents the so-called burrs and generates heat in the through-hole part that occurs during drilling. In order to avoid the clogging of the through-hole part and the trouble of adhesion of cutting debris, drilling is carried out by using the laminated aluminum foil / water-soluble compound layer. In addition, the water-soluble compound layer has an advantage that it can be removed from the substrate by washing the substrate with water after the perforation.
[0003]
For example, (1) Japanese Patent Laid-Open No. 4-92488 and (2) Japanese Patent Laid-Open No. 4-92494 disclose known water-soluble compounds used for such purposes, such as polyethylene glycol and polypropylene on one or both sides of a substrate. (3) JP-A-7-96499 discloses a water-soluble polymer comprising a polyalkylene oxide compound and a polyvalent carboxylic acid and / or a diisocyanate compound, and (4) JP-A-10-6298. Then, it is described that a composition comprising such a water-soluble polymer and a metal compound is disposed.
[0004]
[Problems to be solved by the invention]
However, when through holes are punched in a printed wiring board industrially, a large number of printed wiring boards are stacked and punched, and in the conventional method, any through hole on any of the boards is damaged. In addition, in order to obtain a beautifully finished product free from shavings and the like, considerable skill is required, and the quality often varies.
Especially when drilling continuously with a thin drill with a drill diameter of 0.15 mm or less, plating coverage is one of the recent higher quality requirements, that is, plating was made in the through hole. Since a defect that the uniform plating processability cannot be sufficiently satisfied is likely to occur, a sheet for manufacturing a product with a beautiful finish in any through-hole of all the substrates while using the processing position accuracy and the same are used. It must be said that the development of the drilling method is extremely useful.
[0005]
[Means for Solving the Problems]
As a result of intensive studies by the present inventors in order to solve the above problems, the water-soluble polymer (A) having a molecular weight of 10,000 or more (A) 20 to 100% by weight, and the polyoxyalkylene compound (B) 0 to 300 having a molecular weight of 300 to 10000. It has been found that a printed wiring board perforated sheet obtained by laminating a resin composition layer containing 80% by weight on a support made of a polyvinyl alcohol-based resin can achieve such an object, thereby completing the present invention.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The water-soluble polymer (A) having a molecular weight of 10,000 or more and the polyoxyalkylene compound (B) having a molecular weight of 300 or more and less than 10,000 constituting the resin composition layer of the present invention will be specifically described below.
[0007]
Examples of the water-soluble polymer (A) having a molecular weight of 10,000 or more include polyvinyl alcohol resins, polyoxyalkylene compounds, starch, sodium polyacrylate, cellulose derivatives, casein, sodium alginate, pectin, polyacrylamide, polyethyleneimine, polyvinylpyrrolidone, etc. However, polyvinyl alcohol-based resins and polyoxyalkylene compounds are preferable in that the processing position accuracy during drilling is good.
[0008]
Such polyvinyl alcohol resin may be modified, and the polyvinyl alcohol is produced by homopolymerizing vinyl acetate and further saponifying it. The modified polyvinyl alcohol is produced by saponifying a polymer of vinyl acetate and another unsaturated monomer, or is produced by post-modifying polyvinyl alcohol.
Examples of other unsaturated monomers include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, acrylic acid, methacrylic acid, crotonic acid, maleic acid, and maleic anhydride. , Unsaturated acids such as itaconic acid or salts thereof, mono- or dialkyl esters, nitriles such as acrylonitrile and methacrylonitrile, amides such as acrylamide and methacrylamide, ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, etc. Olefin sulfonic acid or its salt, alkyl vinyl ethers, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethylallyl vinyl ketone, N-vinylpyrrolidone, vinyl chloride, vinyl chloride Polyoxyalkylenes such as redene, polyoxyethylene (meth) allyl ether, polyoxyalkylene (meth) allyl ether such as polyoxypropylene (meth) allyl ether, polyoxyethylene (meth) acrylate, polyoxypropylene (meth) acrylate, etc. (Meth) acrylate, polyoxyethylene (meth) acrylamide, polyoxyalkylene (meth) acrylamide such as polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, Polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, polyoxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene Pyrene vinyl amine.
[0009]
Examples of the post-modification method include a method of converting polyvinyl alcohol into acetoacetate ester, acetalization, urethanization, etherification, grafting, phosphoric esterification, and oxyalkylene.
[0010]
Among these polyvinyl alcohol resins, those having a saponification degree of 65 mol% or more are preferable, and 70 to 100 mol%, particularly 72 to 99 mol% is advantageous. If the saponification degree is less than 65 mol%, the water solubility becomes poor, and it is not preferable because it requires labor for washing after drilling.
[0011]
Examples of the polyoxyalkylene compound include polyalkylene glycol and polyether glycol monoetherified products, monoether monoesterified products, dietherified products, monoesterified products, diesterified products, and the like. Examples include polyethylene glycol, polypropylene glycol, polybutylene glycol and the like.
Monoetherified products include polyoxyethylene monooleyl ether, polyoxyethylene monocetyl ether, polyoxyethylene monostearyl ether, polyoxyethylene monolauryl ether, polyoxyethylene monododecyl ether, polyoxyethylene monononylphenol ether, polyoxyethylene Ethylene monooctyl phenyl ether is exemplified. Examples of the monoether monoester product include methoxypolyethylene glycol (meth) acrylate, ethoxypolyethylene glycol (meth) acrylate, and propoxypolyethylene glycol (meth) acrylate. Dietherized products include polyoxyethylene dioleyl ether, polyoxyethylene dicetyl ether, polyoxyethylene distearyl ether, polyoxyethylene dilauryl ether, polyoxyethylene didodecyl ether, polyoxyethylene dinonylphenol ether, polyoxyethylene Examples include dioctyl phenyl ether.
[0012]
Monoesterified products include polyoxyethylene mono (meth) acrylate, polyoxyethylene monooleate, polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene mono-bovine fatty acid ester, polyglycerin monostearate, etc. Examples of diester compounds include polyoxyethylene di (meth) acrylate, polyoxyethylene dioleate, polyoxyethylene dilaurate, polyoxyethylene distearate, polyoxyethylene dibovine fatty acid ester, polygluterin distearate Etc. are exemplified.
[0013]
The weight-average molecular weight of the polyvinyl alcohol-based resin or polyoxyalkylene compound must be 10,000 or more, preferably 15,000 to 300,000, particularly 30000 to 220,000.
When the weight average molecular weight is less than 10,000, the film forming property is deteriorated, which is not preferable.
[0014]
In the present invention, the resin composition may be composed only of the water-soluble polymer (A) having a weight average molecular weight of 10,000 or more. However, the resin composition is imparted with plasticity to improve adhesion to the support or to form a film. In order to prevent warping and cracking, it is preferable to mix the polyoxyalkylene compound (B) having a weight average molecular weight of 300 or more and less than 10,000, and this effect is obtained when the composition is stored as a film for a long period of time. Prominently demonstrated.
However, the blending amount needs to be 80% by weight or less of the entire composition, preferably 10 to 50% by weight, and more preferably 15 to 45% by weight. When the blending amount exceeds 80% by weight of the entire composition, there is a disadvantage that the solubility is poor.
[0015]
The kind of polyoxyalkylene compound used here is the same as the polyoxyalkylene compound exemplified in the above-described water-soluble polymer (A) having a weight average molecular weight of 10,000 or more, and only the weight average molecular weight is different.
The weight average molecular weight is 300 or more and less than 10,000, preferably 350 to 9000. When the weight average molecular weight is less than 300, bleeding out occurs when the resin composition layer is left for a long period of time. When the weight average molecular weight exceeds 10,000, the water solubility may be lowered.
[0016]
In the present invention, a known additive such as an inorganic powder may be added to the resin composition, if necessary, in addition to a lubricant such as a nonionic surfactant, a rust inhibitor, a stabilizer such as a phosphate ester. There is no problem.
The layer of the resin composition containing the (A) and (B) is used as a laminate laminated with a support made of a polyvinyl alcohol resin .
[0017]
In order to produce such a laminate, the resin composition may be laminated on the support by a general film forming means such as a solution casting method, a melt extrusion method using a T-die or inflation, and the like. Alternatively, a layer of the resin composition may be manufactured in advance and dry laminated with the support. The thickness of the resin composition layer is preferably set in the range of 60 to 1000 μm.
The support is a support made of a polyvinyl alcohol resin, and the same polyvinyl alcohol resin as described above is used as the polyvinyl alcohol resin.
[0018]
In the present invention, the support is made of a polyvinyl alcohol resin.
The thickness of the support made of such a polyvinyl alcohol-based resin is usually preferably 50 to 300 μm, and more preferably 100 to 250 μm.
The laminate used in the present invention prevents lateral misalignment between printed circuit boards during use, and ease of separation when individually separating the printed circuit boards that are superposed prior to dissolution and removal by water after drilling For this reason, it is possible to perform adhesive processing on one side and release processing on the other side.
Furthermore, in order to improve the processing position accuracy, it is also possible to form a concavo-convex pattern on the sheet surface by performing satin processing or embossing on one or both sides of the laminate. Examples of the concavo-convex pattern include a lattice pattern, a silk pattern, a turtle shell pattern, and a rhombus pattern. It is practical to provide irregularities with a surface roughness (measured with a laser microscope) of about 1 to 5 μm and a depth of about 1 to 5 μm (measured with JIS B 0601) for embossing. It is.
[0019]
A method of perforating a printed wiring board using the perforating sheet is performed as follows.
First, the printed wiring board used is usually a board in which a metal foil such as copper and an electrical insulator are laminated and integrated, for example, a metal foil-clad laminate such as an epoxy board in which a metal foil is arranged on the outer layer, and an inner layer. Examples include a multilayer laminate having a printed wiring circuit, a metal foil-clad laminate having a printed wiring circuit, and a metal foil-clad plastic film.
[0020]
A punching sheet according to the present invention is arranged on one or both sides of a printed wiring board, and a through hole having a predetermined size is drilled at a predetermined position of the substrate through the sheet by a drill or a cone.
The punching sheet is preferably arranged so that the support surface of the sheet and the printed wiring board surface are in contact with each other from the viewpoint of improving the processing position accuracy. A metal foil such as an aluminum foil may be interposed between the laminate and the printed wiring board surface.
It is also possible to laminate a plurality of printed wiring boards by interposing sheets between the substrates and perforating at the same time.
After drilling, the laminate is dissolved and removed by washing the substrate with water.
[0021]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
In the examples, “%” and “part” mean weight basis unless otherwise specified. Example 1 (Manufacture of punching sheet)
Sheet 1:
11 parts of a polyvinyl alcohol resin (“GOHSENOL KM-11” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a saponification degree of 78 mol% and a weight average molecular weight of 70000 were dissolved in 59 parts of water. To the aqueous solution, 30 parts of polyethylene glycol having a weight average molecular weight of 3100 (“PEG4000” manufactured by Kishida Chemical Co., Ltd.) was mixed with stirring to obtain 100 parts of an aqueous resin composition solution (solid content: 27.5 parts).
[0022]
A 35 mil applicator was placed on a support made of a polyvinyl alcohol resin (“GOHSENOL KM-11” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) sheet (thickness: 100 μm) having a saponification degree of 78 mol% and a weight average molecular weight of 70,000. The coating film was used and dried at 65 ° C. for 96 hours to form a coating film having a thickness of 160 μm to obtain a punching sheet.
[0023]
Example 2 (Manufacture of punching sheet)
Sheet 2:
In the sheet 1, the use of polyethylene glycol was omitted.
[0024]
Example 3 (Manufacture of punching sheet)
Sheet 3:
The same production as in the above example was performed except that the support in the sheet 1 was changed to a polyvinyl alcohol resin (“GOHSENOL KH-20” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a saponification degree of 80 mol% and a weight average molecular weight of 220,000. .
[0025]
Example 4 (Manufacture of punching sheet)
Sheet 4:
The same production as in the above example was performed except that the support in the sheet 2 was changed to a polyvinyl alcohol resin (“GOHSENOL KH-17” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a saponification degree of 80 mol% and a weight average molecular weight of 150,000. .
[0026]
Example 5 (Manufacture of punching sheet)
Sheet 5:
In the said sheet 1, the same manufacture was performed except having changed the usage-amount of polyvinyl alcohol-type resin into 50 parts and the usage-amount of polyethyleneglycol to 50 parts.
[0027]
Example 6 (Manufacture of punching sheet)
Sheet 6:
The sheet 1 was replaced with a polyvinyl alcohol resin having a saponification degree of 78 mol% and a weight average molecular weight of 70,000, and a polyvinyl alcohol resin having a saponification degree of 72 mol% and a weight average molecular weight of 90000 (“GOHSENOL KP” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.). −08 ”] was used, and the same production as in the same example was performed.
[0028]
Comparative Example 1
An experiment was conducted and evaluated in the same manner as in Example 1 except that an aluminum foil having a thickness of 100 μm was used instead of the polyvinyl alcohol support in Example 1.
[0029]
Comparative Example 2
An experiment was conducted and evaluated in the same manner as in Example 1 except that polyvinyl alcohol having a weight average molecular weight of 9000 was used instead of the polyvinyl alcohol aqueous solution used in Example 1.
[0030]
The printed wiring board was perforated by the following procedure using the above perforating sheet, and the sheet was evaluated.
Two printed wiring boards with a total thickness of 0.4 mm with 18 μm thick copper foil laminated on both sides are stacked, and a perforating sheet as shown in Table 1 is placed at the top, under conditions of room temperature and 30% RH A 1000-hole through hole penetrating the two substrates was formed with a drill having a diameter of 0.15 mm. Regarding the obtained perforated substrate, the processing accuracy of the through hole and the throwing power with plating were evaluated as follows.
[0031]
(Machining position accuracy)
Measure the center of the hole and measure the deviation from a predetermined position with a digital length measuring device ("DR-555-D" manufactured by Dainippon Screen). The average value of the 750th and 1000th holes was calculated to obtain the standard deviation σ, and the (average value + 3σ) value was calculated and evaluated as follows.
◎ ・ ・ ・ less than 15% of drill diameter ○ ・ ・ ・ less than 15-20% of drill diameter △ ・ ・ ・ less than 20-30% of drill diameter × ・ ・ ・ 30% or more of drill diameter
(Plating coverage)
Copper plating is applied to the perforated substrate (plating bath: “Capper Gream 125” manufactured by Meltex), and the cross sections of the first and second substrates 750, 800, 900 and 1000 are confirmed as follows. evaluated.
○ ... Copper plating in all holes is uniformly attached. Δ ... Copper plating uniformity in any one hole is inferior. × ... Copper plating uniformity in two or more holes is inferior. [0033]
The evaluation results of Examples and Comparative Examples are shown in Table 1.
[Table 1]
Machining position accuracy
Example 1 ◎ ○
Example 2 ◎ ○
Example 3 ◎ ○
Example 4
Example 5
Example 6 ◎ ○
Comparative Example 1 ○ ×
Comparative Example 2 ○ △
[0034]
【The invention's effect】
The printed wiring board perforated sheet of the present invention comprises a water-soluble polymer (A) having a weight average molecular weight of 10,000 or more and 20 to 100% by weight, and a polyoxyalkylene compound (B) having a weight average molecular weight of 300 to 10,000 but 0 to 80% by weight. the resin composition layer containing a so formed by laminating a support consisting of a polyvinyl alcohol-based resin when performing the drilling of a printed wiring board, excellent machining position accuracy and plating with around at the time of perforation, after drilling The removability of the sheet is also good.

Claims (6)

A resin composition layer comprising 20 to 100% by weight of a water-soluble polymer (A) having a weight average molecular weight of 10,000 or more and 0 to 80% by weight of a polyoxyalkylene compound (B) having a weight average molecular weight of 300 to less than 10,000, A printed wiring board perforated sheet characterized by being laminated on a support made of a polyvinyl alcohol-based resin .   The printed wiring board perforation according to claim 1, wherein the resin composition layer contains 20 to 90% by weight of the water-soluble polymer (A) and 10 to 80% by weight of the polyoxyalkylene compound (B). Sheet.   The sheet for perforating a printed wiring board according to claim 1, wherein the water-soluble polymer (A) having a molecular weight of 10,000 or more is a polyvinyl alcohol resin or polyethylene glycol. Sheet according to claim 1 to 3, wherein any further printed circuit board drilling sheet, characterized in that formed by laminating a metal foil. A method for perforating a printed wiring board, comprising arranging the sheet according to any one of claims 1 to 4 on a printed wiring board, and perforating a through hole in the substrate. A method for perforating a printed wiring board, wherein the sheet according to any one of claims 1 to 4 is disposed so that a support surface or a metal foil surface thereof is in contact with a printed wiring board surface, and a through hole is perforated in the substrate. .