TWI547358B - Drilling cover - Google Patents

Description

Drilling cover

The present invention relates to a drilling cover plate for use in drilling a copper-clad laminate substrate or a multilayer board.

As a method for drilling a copper-clad laminate substrate or a multi-layer board used for a printed circuit board material, generally, a copper-clad laminate substrate or a multi-layer board is used or a plurality of sheets are overlapped, and a metal such as aluminum is used. A sheet of a resin composition layer formed on the surface of a foil or a metal foil (hereinafter, this sheet is generally referred to as a "hole for drilling" in the present specification) is disposed as a plate against the uppermost portion, and then drilled The method of processing.

In recent years, the requirements for copper-clad laminate substrates or multilayer boards belonging to printed circuit board materials include high density development, productivity improvement, cost reduction and reliability improvement, and high quality of hole position accuracy is required. Drilling processing. In order to cope with these requirements, for example, Patent Document 1 proposes a drilling method using a sheet made of a water-soluble resin such as polyethylene glycol. Further, Patent Document 2 proposes a lubricant sheet for drilling a water-soluble resin layer on a metal foil. Further, Patent Document 3 proposes a drilling cover plate in which a water-soluble resin layer is formed on an aluminum foil on which a thermosetting resin film is formed. Further, in Patent Documents 4 to 5, an auxiliary material which blends the nano powder to extend the life of the drill blade is proposed.

However, compared to the advancement of semiconductor technology, the progress of printed circuit board technology is slow and deviates from semiconductor technology. For this reason, the requirements for higher density and reliability of printed circuit boards are increasing. For example, the smallest drill blade diameter in mass production, starting from 0.2 mm Φ, 0.18mmΦ, 0.15mmΦ, going to 0.105mmΦ. Moreover, there is a very small part that attempts to drill holes of 0.08 mm Φ, 0.075 mm Φ, and 0.05 mm Φ under the anti-laser opening technique. Moreover, because of the relationship between competition caused by globalization and the needs of emerging countries, the need for productivity improvement and cost reduction is endless. Therefore, the new type of drilling cover plate developed in response to such requirements is highly anticipated.

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. Hei 4-92494

Patent Document 2: Japanese Patent Laid-Open No. Hei 5-169400

Patent Document 3: Japanese Patent Laid-Open Publication No. 2003-136485

Patent Document 4: Japanese Utility New Case No. 3134128

Patent Document 5: Japanese Laid-Open Patent Publication No. 2007-281404

An object of the present invention is to provide a drilling cover plate which is superior in hole position accuracy to a conventional drilling cover plate in view of such a situation. The development of such a drilling cover plate is eagerly awaited because it contributes to high density, high reliability, productivity improvement, and cost reduction.

As a result of various reviews to solve the above problems, the present inventors have found that at least one of zinc molybdate and molybdenum trioxide is blended as a solid lubricant (B) in the resin composition of the cover plate for drilling. Better the amount of blending. Thereby, it is found that the bit edge portion is easier to bite, and the hole position accuracy is improved because the centripetality of the drill bit portion is improved. Further, it has been found that since the solid lubricating action of zinc molybdate and molybdenum trioxide increases the lubricity, the discharge of the cutting chips becomes smooth, thereby preventing the cutting chips from falling into pieces and preventing the cutting of the cutting edge into a block shape. Cutting debris causes breakage of the drill bit.

The centripetality referred to herein refers to the advancement of the cutting direction during cutting. For example, when the drill blade portion comes into contact with the resin composition layer of the drilling cover plate, the sharp edge of the tip end of the rotating drill blade edge bites into the surface of the resin composition layer while sliding. If the lubricity is merely improved, the sharp edge of the tip end of the drill blade is likely to slide laterally to impair the centripetality, and the hole position accuracy is deteriorated.

The present invention has been made based on such knowledge, and the gist thereof is as follows.

A cover plate for drilling, wherein a layer composed of a resin composition is formed on at least one surface of a metal supporting foil, characterized in that the resin composition contains zinc molybdate as a solid lubricant (B) At least one of molybdenum trioxide, and the thickness of the resin composition layer is in the range of 0.02 to 0.3 mm.

2. The entry sheet for drilling according to the above item 1, wherein the resin composition contains a water-soluble resin (A).

3. The cover sheet for drilling according to the above item 1, wherein the resin composition is blended in an amount of from 1 part by weight to 40 parts by weight based on 100 parts by weight of the resin component.

4. The casing for drilling according to the above item 1, wherein the zinc molybdate has an average particle diameter of from 1 to 7 μm.

5. The entry sheet for drilling according to the above item 1, wherein the molybdenum trioxide has an average particle diameter of from 3 to 35 μm.

6. The drilling cover according to the above item 1, which is suitable for a drill blade having a diameter of 0.2 mm or less.

7. The drilling cover according to the above item 1, wherein the metal supporting foil has a thickness of 0.05 to 0.5 mm.

8. The drilling cover according to the above item 1, wherein the metal supporting foil has a primer layer as a resin film.

9. The drilling cover according to item 8 above, wherein the primer layer contains the solid lubricant (B).

10. The cover sheet for drilling according to the above item 9, wherein the amount of the solid lubricant (B) blended in the primer layer is from 1 part by weight to 20 parts by weight based on 100 parts by weight of the composition of the primer. Share.

11. The drilling cover according to item 1 above, which is used for processing a copper-clad laminate substrate or a multilayer board.

When the drilling cover plate of the present invention is used, the excellent hole positional accuracy during the drilling process and the excellent lubricity of the resin composition layer can reduce the breakage of the drill blade portion during the drilling process. Therefore, drilling processing with higher density and high quality and excellent productivity is possible. Moreover, the number of stacked sheets can be increased during drilling, which helps to improve productivity and reduce costs.

[Formation of the Invention]

The drilling cover plate of the present invention is a drilling cover plate in which a layer composed of a resin composition (hereinafter referred to as a "resin composition layer") is formed on at least one surface of a metal supporting foil. The entry sheet for drilling according to the present invention is characterized in that the resin composition contains a solid lubricant (B).

In the present invention, the solid lubricant (B) refers to some solids used as a film or a powder for protecting the surface from relative movement and reducing friction and abrasion, and having a melting point of 300 ° C or more. Thermal stability can be maintained without melting in air at a temperature 200 ° C higher than the temperature at which the present invention is used.

Then, the blending amount of at least one of zinc molybdate and molybdenum trioxide is optimized as a solid lubricant (B). According to this, the bit edge of the drill bit becomes easy to be engaged, the centripetality of the drill blade portion is improved, the hole position accuracy is also improved, and the discharge of the cutting chips is smoothed by the increase in the lubricity, and the cutting chips are prevented from falling into pieces. Helps prevent the breakage of the drill bit due to the cutting of the cutting edge of the drill bit.

Further, the resin composition of the present invention is preferably a composition containing the water-soluble resin (A). Here, the water-soluble resin (A) means a water-soluble resin of a water-soluble resin or a non-solid lubricant (B).

Of course, the above resin composition may also contain a well-known thermoplastic water-insoluble resin, a water-insoluble lubricant of the non-solid lubricant (B), and other additives such as a nucleating agent, a coloring agent, and thermal stabilization. Agents, etc.

The resin portion of the above resin composition means a water-soluble resin (A), a water-insoluble lubricant of the non-solid lubricant (B), and a thermoplastic water-insoluble resin. The resin portion of the resin composition is used as a carrier for transporting the solid lubricant (B) to the drill blade portion and the printed circuit board material in addition to its own use.

The solid lubricant (B) is blended in a total amount of 1 part by weight to 40 parts by weight based on 100 parts by weight of the resin portion of the resin composition, preferably 1 part by weight to 30 parts by weight, preferably 5 parts by weight. It is preferably from ～20 parts by weight, more preferably from 10 parts by weight to 20 parts by weight. The solid lubricant (B) did not show an effect in the case of less than 1 part by weight. In the case where the solid lubricant (B) exceeds 40 parts by weight, there is no economic rationality, and the solid lubricant (B) becomes easy to aggregate. Therefore, manufacturing difficulties occur, and as a result, the hole position accuracy may be deteriorated.

The solid lubricant (B) of the present invention is at least one of zinc molybdate (MoO ₄ Zn, melting point: 900 ° C) and molybdenum trioxide (MoO ₃ , melting point: 795 ° C). Although molybdenum trioxide has been pointed out in the past that solid lubricity cannot be exhibited, it has been found to be useful to incorporate a solid lubricant (B) which is a cover plate for drilling. The solid lubricant (B) may contain at least one of these substances.

The solid lubricant (B) described above is found to be satisfactory in that a small amount of blending has a remarkable effect as compared with a solid lubricant such as molybdenum disulfide or mica. A small amount was found to have a remarkable effect, and it was also satisfactory in terms of expanding the option of the resin of the resin composition.

The mechanism of action of the solid lubricant (B) is currently considered to be substantially as described below. First, the lubricant layer contains solids of appropriate hardness, and the front end of the drill blade portion comes into contact with the solid lubricant (B) and is engaged. Therefore, the initial hole position accuracy is good. Second, since the solid lubricant (B) is blended in the lubricant layer, the surface of the drill blade and the groove, and the solid lubricant (B) are adhered to the wall of the printed circuit board material. Since the solid lubricant (B) is solid and has a volume and hardness, it continues to exist between the copper-clad laminate substrate or the multilayer plate and the drill blade portion to improve lubricity and suppress wear of the drill blade portion. Third, since the solid lubricant (B) is adhered to the groove of the drill blade portion, the lubricity is improved by the solid lubricating action, and the discharge of the cutting chips is smoothly performed, so that the cutting chips can be prevented from being aggregated into pieces.

In addition, the wear of the drill blade can be classified into two types. First, initial wear. That is, the portion of the drill blade that is subjected to the impact at the beginning of use may be damaged. Since the aforementioned solid lubricant (B) has a particularly remarkable lubricating effect, the initial wear of the drill blade portion is suppressed as compared with the case where the solid lubricant (B) is not contained. Second, normal wear. That is, the drill blade portion is worn with the accumulation of the number of drill holes. However, since the solid lubricant (B) has a specific lubricating effect, normal wear is also suppressed as compared with the case where the solid lubricant (B) is not contained. Therefore, the hole positional accuracy is in the absence of the solid lubricant (B), and the deterioration condition is proportional to the cumulative number of drilled holes, whereas in the case of the solid lubricant (B), it can be gradually suppressed.

The solid lubricant (B) may also be blended with a resin film (hereinafter referred to as a primer layer) provided on the metal supporting foil. The primer layer is the interface with the aluminum foil, so fine filling of the primer layer is helpful for hole position accuracy. The solid lubricant (B) is preferably blended in an amount of from 1 part by weight to 20 parts by weight per 100 parts by weight of the composition of the primer layer, and more preferably from 5 parts by weight to 10 parts by weight. When the blending amount of the solid lubricant (B) is less than 1 part by weight, no effect is observed. When the blending amount of the solid lubricant (B) is more than 20 parts by weight, there is no economic rationality and the adhesion between the thinner and different primer layers and the metal supporting foil is impaired. Any of a resin blended with a primer layer of the solid lubricant (B), a thermosetting resin or a thermoplastic resin may be applied. When the resin of the primer layer is a thermosetting resin, the hole positional accuracy is preferable.

It is more preferable to select the most suitable type, particle size, and blending amount of the solid lubricant (B) in accordance with the specifications of the copper-clad laminate substrate or the multilayer board.

For example, when zinc molybdate is used as the solid lubricant (B), the reason for the effect is as follows. The zinc molybdate has a layered structure, a particle diameter of 0.2 μm to 15 μm, an average particle diameter of 1 to 7 μm, and a solid having a volume and an appropriate hardness. A preferred average particle diameter is 2 to 6 μm. More preferably, the average particle diameter is from 3 to 5 μm. Because of this characteristic, the cutting edge of the drill can be easily engaged for the small-diameter drill blade whose hole position accuracy is important. Further, since the zinc molybdate is thin due to the layered structure and is easily caught in the groove when the drill blade is rotated, it contributes to the discharge of the cutting chips.

The reason why the effect of molybdenum trioxide is effective is as follows. Molybdenum trioxide is oxidized by molybdenum disulfide, and has a columnar structure, a particle diameter of 0.7 μm to 55 μm, an average particle diameter of 3 to 35 μm, and a solid having a volume and an appropriate hardness. A preferred average particle size is 5 to 20 μm. More preferably, the average particle diameter is from 10 to 18 μm. Because of this characteristic, the cutting edge of the drill can be easily engaged for the small-diameter drill blade whose hole position accuracy is important. Further, since the molybdenum trioxide has a smaller average particle diameter than the groove of the drill blade portion, it is easily caught in the groove when the drill blade portion rotates, thereby contributing to the discharge of the cutting chips.

Regarding the particle diameter of the solid lubricant (B), the average particle diameter value is more important than the maximum particle diameter value. The reason is that the particle diameter of the solid lubricant which accounts for a high proportion in the resin composition has an influence on the hole position accuracy and lubricity of the characteristics of the cover plate for drilling. Therefore, in order to improve the performance of the cover plate for drilling, it is important to manage the average particle diameter of the solid lubricant (B). Therefore, the ratio of the largest particle diameter in the particle size distribution of the solid lubricant (B) is too high, so that the average particle diameter value is greatly increased, and the originally desired solid lubricity is sometimes lowered, which is not preferable. The particle size determination method of the solid lubricant (B) is to disperse the sample in a solution consisting of a 0.2% solution of hexametaphosphoric acid and a few drops of 10% of a cyclopropylpyritol (Thritone), using a laser diffraction type. A particle size distribution measuring device (model: SALD-2100, manufactured by Shimadzu Corporation) was used to measure the maximum length of the solid lubricant (B) particles projected by each. Next, the particle size distribution curve was calculated. The range of the curve is taken as the particle diameter of the solid lubricant (B), and the particle diameter at which the peak of the curve content is the largest is taken as the average particle diameter.

In particular, when the solid lubricant (B) is zinc molybdate and molybdenum trioxide, it cannot be said that it is completely insoluble in water but has non-swelling property. Therefore, there is no need for a swellable solid lubricant to strictly manage the degree of hydration, which is industrially advantageous. Here, the definition of non-swelling property is that an aqueous solution in which 10 parts by weight of a solid lubricant is blended in 90 parts by weight of water is thoroughly mixed and stirred, and after standing for 1 hour, the precipitation height of the solid lubricant and the sedimentation height ratio are measured. More than 90% is defined as dispersion or swelling, and the precipitation height is defined as swelling at a ratio of more than 50% to less than 90%, and non-swelling is defined as a precipitation height ratio of less than 50%. The zinc molybdate of the present invention has a height of 66 mm to the liquid surface, a top surface of the precipitate portion of the zinc molybdate of 21 mm, and a sedimentation height ratio of 32%, which is an example in which the separation is apparently two layers. Similarly, the molybdenum trioxide of the present invention has a height of 35 mm to the liquid surface, a top surface of the precipitation portion of the molybdenum trioxide of 5 mm, and a sedimentation height ratio of 14%, which is the top surface of the precipitation portion of the molybdenum trioxide to the liquid surface. It is an example of white turbidity.

Such a property has the following advantages in the production of a solution of the water-soluble resin (A). It is easy to disperse evenly and is not easy to aggregate. After the drilling process, when zinc molybdate or molybdenum trioxide remains in the pores, it is easier to clean. However, in the case of producing a solution of the water-soluble resin (A), since the solid lubricant (B) generates a concentration gradient, it is necessary to stir.

When the hardness of the solid lubricant (B) exceeds, for example, the range of Mohs's hardness of 5, it becomes an abrasive and it is unsuitable. The optimum blending amount of the solid lubricant (B) varies depending on the specifications of the printed circuit board to be drilled. Compared with a printed circuit board material containing no inorganic filler, a printed circuit board material containing an inorganic filler is preferable because a relatively large amount of solid lubricant (B) is blended because the wear of the drill bit is relatively large.

The type of the water-soluble resin (A) is not particularly limited as the water-soluble resin, and examples thereof include polyethylene oxide, polypropylene oxide, sodium polyacrylate, polypropylene decylamine, and polyethylene tetrahydro ketone. One or two or more types of the group consisting of carboxymethylcellulose, polytetramethylene glycol, and polyolefin of polyolefin glycol are preferred. The polyester of polyolefin ethylene glycol is a condensate obtained by reacting a polyolefin glycol with a dibasic acid. Regarding polyolefin ethylene glycol, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol or ethylene glycols exemplified by these copolymers, and in the case of dibasic acids, it is preferable to use phthalic acid and isophthalic acid. A partial ester, an acid anhydride or the like of a polyvalent carboxylic acid such as formic acid, terephthalic acid, azelaic acid or pyromellitic acid is preferably selected. For the water-soluble lubricant of the non-solid lubricant (B), for example: polyethylene glycol, polypropylene glycol; polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene Monoethers of polyoxyethylene exemplified by lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, etc.; polyoxyethylene monostearate, polyoxyethylene sorbitan monohard a polyglycerol monostearate such as hexaglycerol monostearate or hexadecanol monostearate; a polyoxyethylene propylene copolymer, etc., preferably 1 or 2 It is preferred that the above is appropriately blended.

The water-insoluble resin which is thermoplastic is not particularly limited, and a widely known substance can also be applied. For example, amide-based rubber, butadiene-based rubber, ester-based rubber, olefin-based rubber, urethane-based rubber, styrene-based rubber, polybutene, low-density polyethylene, and chlorinated Polyethylene, metallocene-based polyolefin resin, ethylene ‧ acrylate ‧ maleic anhydride copolymer, ethylene ‧ (meth) acrylate glycidyl ester copolymer, ethylene ‧ vinyl acetate copolymer resin, denaturation Ethylene/vinyl acetate copolymer resin, ethylene ‧ (meth)acrylic copolymer resin, polyionic polymer resin, ethylene ‧ (meth) acrylate copolymer resin, and the like.

The water-insoluble lubricant of the non-solid lubricant (B) is not particularly limited, and a widely known substance can also be applied. For example, an amide-based compound such as ethylene bis-lipidamine, oleic acid amide, stearylamine or methylenebisstearylamine, lauric acid, stearic acid, palmitic acid, oleic acid, etc. The fatty acid ester compound exemplified by the fatty acid compound, butyl oleate, butyl oleate, and ethylene glycol laurate, and an aliphatic hydrocarbon-based compound exemplified by a liquid paraffin or a polyethylene wax. A higher aliphatic alcohol exemplified by oleic acid alcohol or the like.

The thickness of the resin composition layer differs depending on the diameter of the drill blade portion used in the drilling process, the configuration of the copper-clad laminate substrate to be processed, or the multilayer plate, but is usually in the range of 0.02 to 0.3 mm. It is preferred to suitably select within the range of 0.02 to 0.2 mm. When the thickness of the resin composition layer is less than 0.02 mm, a sufficient lubricating effect is not obtained, and the load on the drill blade portion is increased to cause breakage of the drill blade portion. On the other hand, when the thickness of the resin composition layer exceeds 0.3 mm, the occurrence of the above-described resin composition being caught in the drill blade portion increases.

Further, in the method for forming the resin composition layer, for example, a coating or drying method of directly applying a hot solution or solution of the resin composition to the metal supporting foil according to a coating method or a resin is prepared in advance. A film of the composition and a hot-melt method in which the metal supporting foil is bonded to the metal supporting foil. In this case, it is preferable to form a resin film (primer layer) on the metal supporting foil in advance so that the metal supporting foil and the resin composition can be laminated and integrated. Details will be described later.

Further, in the case where the solution of the resin composition is directly applied to the metal supporting foil and dried by a coating method or the like, the solution to be used is preferably a solution containing water and a solvent having a boiling point lower than water. The solvent having a boiling point lower than water is not particularly limited. For example, ethanol such as alcohol, methanol or isopropyl alcohol may be used, and a low boiling point solvent such as methyl ethyl ketone or acetone may be used. As the other solvent, a solvent obtained by mixing a portion of tetrahydrofuran or acetonitrile having a high mutual solubility with a resin composition in water or an alcohol can be used. The blending ratio of water and solvent with a boiling point lower than water must be in the range of 90/10~50/50, preferably in the range of 80/20~50/50, in the range of 70/30~50/50. More preferably, it is particularly good in the range of 60/40~50/50. When the blending ratio of the solvent having a boiling point lower than water is less than 10, the water-soluble resin (A) may not easily form dense spherulites. In the case where the blending ratio of the solvent having a boiling point lower than water exceeds 50, there is a hindrance to industrial stability production.

Further, in the case of a coating method, a hot-melt method, or the like, a solution in which a solution of a resin composition is applied directly to a metal supporting foil, and a heating and drying method is used, the temperature of the above-mentioned drilling cover plate must be 5 Decrease from 120 ° C to 160 ° C to room temperature in ~30 seconds. A high drying temperature of more than 160 ° C has an obstacle to industrial stability and is not ideal. Further, it is not preferable that condensation occurs in the subsequent step as compared with the normal temperature at a low cooling temperature.

The metal supporting foil used in the drilling cover plate of the present invention is not particularly limited as long as it has high adhesion to the resin composition and can withstand the impact from the drill blade. The thickness of the metal supporting foil is usually 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm. When the thickness of the metal supporting foil is less than 0.05 mm, the laminated substrate is likely to be burred at the time of drilling, and when it exceeds 0.5 mm, it is difficult to discharge the cutting chips during the drilling. As the metal species of the metal supporting foil, for example, aluminum can be used. As the material of the aluminum foil, aluminum having a purity of 95% or more is preferable, and for example, 5052, 3004, 3003, 1N30, 1N99, 1050, 1070, 1085, 8021, and the like specified in JIS (Japanese Industrial Standard)-H4160. Since high-purity aluminum is used in the metal supporting foil, the impact from the drill blade portion can be alleviated, and the nip property of the tip end portion of the drill blade portion can be improved, because the interaction between the resin composition and the lubrication effect of the drill blade portion can be improved. The hole position accuracy of the machined hole. Further, it is preferable to use a metal supporting foil having a resin film (primer layer) having a thickness of 0.002 to 0.02 mm formed on the surface in advance in order to adhere to the resin composition. When the solid lubricant (B) is blended with the resin film, the thickness of the resin film can be appropriately selected in accordance with the particle diameter of the solid lubricant (B). The resin to be used for the resin film is not particularly limited as long as it can improve the adhesion to the resin composition, and any of a thermoplastic resin and a thermosetting resin can be used. The thermoplastic resin is, for example, an urethane-based polymer, a vinyl acetate-based polymer, a vinyl chloride-based polymer, a polyester-based polymer, an acryl-based polymer, or a copolymer of these. The thermosetting resin is, for example, a resin such as an epoxy-based resin or a cyanate-based resin.

The drilling cover plate of the present invention is used for drilling a printed circuit board material such as a copper-clad laminate substrate or a multilayer board. Specifically, the cover plate for drilling may be disposed on the uppermost portion of the copper-clad laminate substrate or the multi-layer board or the uppermost portion of the plurality of sheets, and the side of the metal supporting foil may be in contact with the printed circuit board material, and the resin may be The side of the composition layer is drilled.

The above is only an example of the embodiment of the present invention, and various modifications can be added within the scope of the patent application.

[Examples]

Hereinafter, the effects of the examples of the present invention will be compared with the comparative examples outside the scope of the present invention. In addition, "polyethylene glycol" is abbreviated as "PEG", and "polyethylene oxide" is abbreviated as "PEO".

<Example 1>

30 parts by weight of polyethylene oxide (ALTOP MG-150 manufactured by Mingsei Chemical Co., Ltd.) having a weight average molecular weight of 150,000, and polyethylene glycol having a weight average molecular weight of 20,000 (PEG 20000 manufactured by Sanyo Chemical Industries Co., Ltd.) 70 parts by weight was dissolved in a water/MeOH (methanol) mixed solution in a state where the resin solid content became 30%. The ratio of water to MeOH at this time was 60/40. Further, in the solution of the water-soluble resin composition, zinc molybdate (manufactured by Nippon Inorganic Chemicals Co., Ltd., particle size: 0.4 μm to 13 μm, average particle diameter: 3 μm) is used as the solid lubricant (B), relative to water solubility. 100 parts by weight of the resin composition was blended in an amount of 5 parts by weight to be sufficiently dispersed. A solution of the water-soluble resin composition was applied to an aluminum foil having an epoxy resin film having a thickness of 0.01 mm on one side (using aluminum foil: 1N30, thickness 0.1 mm, manufactured by MITSUBISHI ALUMINUM Co., Ltd.). The thickness of the water-soluble resin composition layer after drying was set to 0.05 mm, dried in a dryer at 120 ° C for 5 minutes, and then cooled to room temperature to obtain a cover plate for drilling.

<Examples 2 to 14>

According to Example 1, the water-soluble resin composition shown in Table 1 was prepared, and a water-repellent resin composition having a thickness of 0.05 mm after drying was prepared.

<Comparative Examples 1 to 11>

According to Example 1, the water-soluble resin composition shown in Table 1 was prepared, and a water-repellent resin composition having a thickness of 0.05 mm after drying was prepared.

<Evaluation method>

The following evaluations were performed on each sample of the drilling cover sheets produced in the examples and the comparative examples.

(1) Hole position accuracy

The hole for drilling is placed over the overlapping copper-clad laminate substrate, and the resin composition layer is placed upward to perform drilling. Each drill bit is drilled with 6,000 hits and repeated using four drill tips. Holes of 1 to 1,500 and 1 to 6,000 hits per 1 part of the drill blade are measured by overlapping hole gauges using a hole position coordinate measuring device (Model: HA-1AM, manufactured by Hitachi Via Mechanics Co., Ltd.) The deviation between the hole position on the back surface of the lowermost plate of the layer substrate and the specified coordinates was calculated, and the average value and the standard deviation (σ) were calculated to calculate "average value + 3σ". Next, the average value of the "average value + 3 σ" of the four-part drill blade portion was calculated, and the results are shown in Table 1.

It is determined that the hole position accuracy of 1 to 1,500 hits is not worn by the drill blade portion, and the hole position accuracy of the drill blade portion is 1 to 6,000 hits, which is used as a criterion for determining the hole position accuracy. When 1 to 1,500 hits and 1 to 6,000 hits are judged as "○", the total evaluation is "○".

(2) Particle size determination method of solid lubricant (B)

The particle size of the solid lubricant (B) is determined by dispersing the sample in a solution consisting of 0.2% hexametaphosphoric acid solution and a few drops of 10% cyclopropylpyr (Thritone), using a laser diffraction particle size distribution measurement. The device (model: SALD-2100, manufactured by Shimadzu Corporation) was used to measure the maximum length of the solid lubricant (B) particles projected by each. The particle size distribution curve is then calculated. The range of the curve is taken as the particle diameter of the solid lubricant (B), and the particle diameter at which the peak of the curve content is the largest is taken as the average particle diameter.

Composition of water-soluble resin (A):

(1) 30 parts by weight of polyethylene oxide (ALTOP MG-150, Mw = 150,000) manufactured by Mingcheng Chemical Industry Co., Ltd., and polyethylene glycol (PEG 20000, Mw = 200,000 manufactured by Sanyo Chemical Industries Co., Ltd.) 70 parts by weight , a total of 100 parts by weight.

(2) Polyether ester (PAOGEN PP-15, manufactured by Daiichi Kogyo Co., Ltd., Mw = 100,000) 20 parts by weight, polyethylene glycol (PEG 4000S manufactured by Sanyo Chemical Industries Co., Ltd., Mw = 4,000) 80 weight Parts, a total of 100 parts by weight.

Type of solid lubricant (B):

(3) Zinc molybdate (manufactured by Nippon Inorganic Chemical Industry Co., Ltd., particle size 0.4μm~13μm, average particle size 3μm, layered structure)

(4) Molybdenum trioxide (manufactured by Nippon Inorganic Chemicals Co., Ltd., particle size 0.7μm to 55μm, average particle size 16μm, columnar structure)

(5) Molybdenum disulfide (M-5 Powder manufactured by DAIZO Co., Ltd., particle size 0.5 to 29 μm, average particle diameter 5 μm, layered structure)

(6) Swellable mica (ME-100 manufactured by Co-op Chemical, particle size 5 to 7 μm, layered structure)

(7) Non-swelling mica (MK-200 manufactured by Co-op Chemical, particle size 5 to 8 μm, layered structure)

(8) Unblended solid lubricant (B)

The amount of solid lubricant (B) blended:

The solid lubricant (B) is blended in any one of 0, 5, 10, 20, 40, 60, and 80 parts by weight with respect to 100 parts by weight of the resin component of the resin composition.

Drilling processing conditions:

(1) Drill blade diameter: 0.2 mm Φ (C-CFU020S manufactured by Tungaloy Co., Ltd.), rotation speed: 200,000 rpm, feed rate 20 μm/rev., rising speed: 25.4 m/min, processing substrate is free of inorganic filler HL832 0.2mmt, Cu 12μ, overlap 5

(2) Drill blade diameter: 0.2 mm Φ (C-CFU020S manufactured by Tungaloy Co., Ltd.), rotation speed: 200,000 rpm, feed rate 20 μm/rev., rising speed: 25.4 m/min, and the processing substrate is added with inorganic filler. HL832HS 0.2mmt, Cu 12μ, overlap 5

According to the results of Table 1, the samples of Examples 1 to 14 were found to be superior to the samples of Comparative Examples 1 to 11 in that the drill blade edge wear stage and the drill blade edge wear stage were not performed, and the hole position accuracy was excellent. That is, the zinc molybdate and the molybdenum trioxide of the present invention are remarkably excellent in hole positional accuracy as compared with the molybdenum disulfide, the swellable mica, and the non-swellable mica used in the prior art.

[Industrial use]

According to the present invention, it is possible to provide a drilling cover plate which is excellent in hole position accuracy and which reduces breakage of the drill blade portion as compared with the conventional drilling cover plate.

Fig. 1 is a scanning electron micrograph (x 10000) of zinc molybdate (manufactured by Nippon Inorganic Chemicals Co., Ltd., particle diameter: 0.4 μm to 13 μm, average particle diameter: 3 μm, layered structure).

Fig. 2 is a scanning electron micrograph (×10000) of molybdenum trioxide (Nippon Inorganic Chemical Industry Co., Ltd., particle diameter: 0.7 μm to 55 μm, average particle diameter: 16 μm, columnar structure).

Fig. 3 is a comparison diagram of the hole positional accuracy of the examples and comparative examples after the drilling processing condition 1.

Fig. 4 is a graph showing the comparison of the hole positional accuracy of the examples and the comparative examples after the drilling processing condition 2.

Claims (10)

A drilling cover plate is a drilling cover plate formed with a layer composed of a resin composition on at least one surface of a metal supporting foil, characterized in that the resin composition contains a solid lubricant (B) Zinc molybdate, and the thickness of the resin composition layer is in the range of 0.02 to 0.3 mm. The cover sheet for drilling according to the first aspect of the invention, wherein the resin composition contains a water-soluble resin (A). The cover sheet for drilling according to the first aspect of the invention, wherein the resin composition is blended with the solid lubricant (B) in an amount of from 1 part by weight to 40 parts by weight based on 100 parts by weight of the resin component. The cover plate for drilling according to the first aspect of the invention, wherein the zinc molybdate has an average particle diameter of 1 to 7 μm. For example, the drilling cover plate of the first application of the patent scope is applicable to a drill blade having a diameter of 0.2 mm or less. The cover plate for drilling according to claim 1, wherein the metal support foil has a thickness of 0.05 to 0.5 mm. The cover plate for drilling according to the first aspect of the invention, wherein the metal support foil has a primer layer as a resin film. A drilling cover according to claim 7, wherein the primer layer contains the solid lubricant (B). The cover plate for drilling according to claim 8, wherein the amount of the solid lubricant (B) blended in the primer layer is 1 part by weight to 20 parts by weight relative to 100 parts by weight of the composition of the primer. Share. The drilling cover plate of claim 1 is used for processing a copper-clad laminate substrate or a multilayer plate.