JPWO2012091179A1 - Entry sheet for drilling holes - Google Patents

Abstract

An object of the present invention is to provide an entry sheet for drilling that has excellent hole position accuracy and reduced breakage of a drill bit as compared with a conventional drilling entry sheet. An entry sheet for drilling, in which a layer made of a resin composition is formed on at least one side of a metal supporting foil, wherein the resin composition is blended with a solid lubricant containing at least one of zinc molybdate and molybdenum trioxide. An entry sheet for drilling, characterized in that the resin composition layer has a thickness in the range of 0.02 to 0.3 mm.

Description

  The present invention relates to an entry sheet for drilling used for drilling a copper-clad laminate or multilayer board.

  As a drilling method for copper-clad laminates or multilayer boards used for printed wiring board materials, one or more copper-clad laminates or multilayer boards are stacked, and aluminum or the like is used as a backing plate on the top. There is a method in which a metal foil alone or a sheet in which a resin composition layer is formed on the surface of the metal foil (hereinafter, this sheet is usually referred to as an “entry sheet for drilling”) is drilled. Generally adopted.

In recent years, the demand for copper-clad laminates or multilayer boards, which are printed wiring board materials, has increased density, improved productivity and reduced costs, improved reliability, and improved high-quality drilling such as improved hole location accuracy. Processing is required. In order to meet these requirements, for example, Patent Document 1 proposes a drilling method using a sheet made of a water-soluble resin such as polyethylene glycol. In Patent Document 2, a drilling lubricant sheet in which a water-soluble resin layer is formed on a metal foil is proposed. Furthermore, Patent Document 3 proposes an entry sheet for punching in which a water-soluble resin layer is formed on an aluminum foil on which a thermosetting resin thin film is formed. And in patent documents 4-5, the auxiliary material which mix | blends nanopowder and extends the lifetime of a drill bit is proposed.
However, compared with the progress of semiconductor technology, that of printed wiring board technology is slow, and there is a deviation from semiconductor technology. For this reason, demands for higher density and higher reliability for printed wiring boards are becoming increasingly sophisticated. For example, the minimum drill bit diameter in mass production is shifting from 0.2 mmφ to 0.105 mmφ through 0.18 mmφ and 0.15 mmφ. Also, in order to counter the laser drilling technology, drilling of 0.08 mmφ, 0.075 mmφ, and 0.05 mmφ has been attempted in a small part. Furthermore, demands for improving productivity and reducing costs are unrelenting due to competition from globalization and demand in emerging countries. Therefore, development of a new entry sheet for drilling that meets such requirements is eagerly desired.

JP-A-4-92494 JP-A-5-169400 JP 2003-136485 A Utility Model 3134128 JP 2007-281404 A

  In view of the present situation, an object of the present invention is to provide an entry sheet for drilling that is superior in hole position accuracy as compared to conventional drilling entry sheets. Such a drilling entry sheet contributes to high density, high reliability, productivity improvement, and cost reduction, and therefore is eagerly developed.

  As a result of various studies to solve the above-mentioned problems, the present inventors have found that the resin composition of the drill hole entry sheet contains at least zinc molybdate and molybdenum trioxide as a solid lubricant (B). One was blended and the blending amount was optimized. As a result, it has been found that the drill bit is easy to bite and the hole position accuracy is improved by improving the centering property of the drill bit. In addition, the solid lubrication action of zinc molybdate and molybdenum trioxide increases lubricity and smooth discharge of chips, preventing chips from becoming lumps and falling, It was found that the problem of breakage of the drill bit due to the step of the drill bit can be prevented.

  Here, the centripetal property refers to straightness in the cutting direction during cutting. For example, at the point where the drill bit comes into contact with the resin composition layer of the entry sheet for drilling, the cutting edge at the tip of the rotating drill bit bites on the surface of the resin composition layer while sliding. Simply increasing the lubricity simply causes the tip of the drill bit to slip sideways, thus impairing the centering property and deteriorating the hole position accuracy.

The present invention has been made based on such findings, and the gist thereof is as follows.
(1) A drill hole entry sheet in which a layer made of a resin composition is formed on at least one side of a metal supporting foil, wherein the resin composition contains zinc molybdate and molybdenum trioxide as a solid lubricant (B). An entry sheet for drilling, characterized in that it contains at least one 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 (1), wherein the resin composition includes a water-soluble resin (A).

(3) The said resin composition mix | blends the said solid lubricant (B) 1 to 40 weight part in total with respect to 100 weight part of the resin part, The said (1) characterized by the above-mentioned. Entry sheet for drilling.

(4) The entry sheet for drilling according to (1), wherein the zinc molybdate has an average particle diameter of 1 to 7 μm.

(5) The entry sheet for drilling according to (1), wherein the molybdenum trioxide has an average particle size of 3 to 35 μm.

(6) The entry sheet for drilling according to (1), which is applied to a drill bit diameter of 0.2 mmφ or less.

(7) The entry sheet for drilling according to (1), wherein the metal supporting foil has a thickness in a range of 0.05 to 0.5 mm.

(8) The entry sheet for drilling holes according to (1) above, which has a primer layer as a resin film on the metal supporting foil.

(9) The entry sheet for drilling according to (8), wherein the primer layer contains the solid lubricant (B).

(10) The drill according to (9), wherein the amount of the solid lubricant (B) in the primer layer is 1 to 20 parts by weight with respect to 100 parts by weight of the primer composition. Entry sheet for drilling.

(11) The entry sheet for drilling according to (1), which is used for processing a copper-clad laminate or a multilayer board.

  By using the entry sheet for drilling of the present invention, it is possible to reduce breakage of the drill bit during drilling due to excellent hole positioning accuracy during drilling and excellent lubricity of the resin composition layer. it can. As a result, it is possible to design a higher density, and to perform drilling with high quality and excellent productivity. Alternatively, it is possible to increase the number of stacked holes to be drilled at a time, contributing to productivity improvement and cost reduction.

Scanning electron micrograph (× 10000) of zinc molybdate (manufactured by Nippon Inorganic Chemical Industry Co., Ltd., particle size 0.4 μm to 13 μm, average particle size 3 μm, layered structure) Scanning electron micrograph of molybdenum trioxide (× 10000) (Nippon Inorganic Chemical Industry Co., Ltd., particle size 0.7-55 μm, average particle size 16 μm, columnar structure) Comparison of hole position accuracy between Example and Comparative Example when drilled under drilling condition 1 Comparison of hole position accuracy between Example and Comparative Example when drilled under drilling conditions 2

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

  In the present invention, the solid lubricant (B) is any solid used as a thin film or powder to protect the surface from damage during relative motion and reduce friction and wear, and has a melting point of 300 ° C. or higher. It is a material that is thermally stable in air at a temperature of 200 ° C., which is higher than the use temperature of the present invention, and is not melted and is a solid.

  And as a solid lubricant (B), the compounding quantity of at least one of zinc molybdate and molybdenum trioxide is optimized. This makes it easier for the drill bit to bite, improving the drill bit's centripetalness, improving the hole position accuracy, and improving the lubricity and smoothing the discharge of the chip, thereby reducing the amount of the chip. It is prevented from falling in the form of lumps, and this contributes to the prevention of the problem of breakage of the drill bit due to the drill bit stepping on the damped chips.

  Moreover, it is preferable that the resin composition of this invention is a composition containing water-soluble resin (A). Here, the water-soluble resin (A) refers to a water-soluble lubricant that is not a water-soluble resin or a solid lubricant (B).

  Of course, the resin composition includes known thermoplastic water-insoluble resins, water-insoluble lubricants that are not solid lubricants (B), and other additives such as nucleating agents, colorants, and heat stabilizers. Etc. may also be included.

  The resin component of the resin composition refers to a water-soluble resin (A), a water-insoluble lubricant that is not a solid lubricant (B), and a thermoplastic water-insoluble resin.

  The solid lubricant (B) is preferably blended in a total amount of 1 to 40 parts by weight with respect to 100 parts by weight of the resin component of the resin composition, and preferably 1 to 30 parts by weight. 5 to 20 parts by weight is more preferable, and 10 to 20 parts by weight is most preferable. When the solid lubricant (B) is less than 1 part by weight, the effect is not exhibited. When the solid lubricant (B) exceeds 40 parts by weight, there is no economic rationality and the solid lubricant (B) tends to aggregate. As a result, manufacturing difficulties occur, and as a result, the hole position accuracy may deteriorate.

In the present invention, the solid lubricant (B) is at least one of zinc molybdate (MoO ₄ Zn, melting point 900 ° C.) and molybdenum trioxide (MoO ₃ , melting point 795 ° C.). Molybdenum trioxide has been conventionally said to not exhibit solid lubricity, but has been found to be useful as a solid lubricant (B) to be blended in an entry sheet for drilling. Solid lubricant (B) should just contain at least 1 sort or more among these.
The above-mentioned solid lubricant (B) is preferable because it produces a remarkable effect with a small amount of blending compared to solid lubricants such as molybdenum disulfide and mica. Expressing a remarkable effect in a small amount is also preferable in terms of expanding the options of the resin as the resin composition.

The mechanism of action of the solid lubricant (B) is considered to be as follows. First, when the lubricant layer contains a solid having an appropriate hardness, the tip of the drill bit hits the solid lubricant (B) and bites it. For this reason, the initial hole position accuracy is good. Second, since the solid lubricant (B) is blended in the lubricant layer, the solid lubricant (B) adheres to the surface and grooves of the drill bit and the hole wall of the printed wiring board material. Since the solid lubricant (B) is solid and has a volume and hardness, the solid lubricant (B) is always present between the copper-clad laminate or the multilayer board and the drill bit to improve lubricity and suppress wear of the drill bit. Thirdly, since the solid lubricant (B) adheres to the groove of the drill bit, the solid lubrication action increases the lubricity, and the discharge of the chips becomes smooth, so that the chips are prevented from becoming damped. Is done.
By the way, wear of a drill bit can be classified into two types. First, there is initial wear. That is, in the drill bit, the part that receives the impact is damaged at the beginning of use. Due to the remarkable lubricating effect peculiar to the solid lubricant (B), the initial wear of the drill bit is suppressed as compared with the case where the solid lubricant (B) is not contained. Second, there is steady wear. That is, the drill bit wears with the cumulative number of holes. However, since there is a lubricating effect peculiar to the solid lubricant (B), steady wear is also suppressed as compared with the case where the solid lubricant (B) is not contained. Therefore, the hole position accuracy deteriorates in proportion to the cumulative number of holes when the solid lubricant (B) is not included, but may be gradually suppressed when the solid lubricant (B) is included.

  You may mix | blend a solid lubricant (B) with the resin film (henceforth a primer layer) provided on metal support foil. Since the primer layer is an interface in contact with the aluminum foil, closely filling the primer layer contributes to the hole position accuracy. The solid lubricant (B) is preferably blended in a total of 1 to 20 parts by weight and more preferably 5 to 10 parts by weight with respect to 100 parts by weight of the primer composition. When the amount of the solid lubricant (B) is less than 1 part by weight, the effect is not exhibited. When the compounding quantity of a solid lubricant (B) exceeds 20 weight part, there is no economical rationality and the adhesiveness of a primer layer and metal support foil which are thin may be inhibited. As the resin for the primer layer in which the solid lubricant (B) is blended, either a thermosetting resin or a thermoplastic resin can be applied. The resin of the primer layer is more preferably a thermosetting resin in terms of hole position accuracy.

It is more preferable that the solid lubricant (B) is selected in accordance with the specifications of the copper-clad laminate or multilayer board, and the optimum type, particle size, and blending amount are selected.
The reason why, for example, zinc molybdate is effective as the solid lubricant (B) is as follows. Zinc molybdate has a layered structure, a particle size in the range of 0.2 μm to 15 μm, an average particle size of 1 to 7 μm, and a solid having a volume and appropriate hardness. The average particle size is preferably 2 to 6 μm. More preferably, the average particle size is 3 to 5 μm. Because of this characteristic, the drill bit tends to bite in a small-diameter drill bit where the hole position accuracy is important. Further, since zinc molybdate is thin and has a layered structure, it is easy to be caught in the groove when the drill bit is rotated, which contributes to discharge of chips.
The reason why molybdenum trioxide has the effect is as follows. Molybdenum trioxide is obtained by oxidizing molybdenum disulfide, has a columnar structure, has a particle size in the range of 0.7 to 55 μm, has an average particle size of 3 to 35 μm, and has a volume and an appropriate hardness. The average particle size is preferably 5 to 20 μm. More preferably, the average particle size is 10 to 18 μm. Because of this characteristic, the drill bit tends to bite in a small-diameter drill bit where the hole position accuracy is important. In addition, since molybdenum trioxide has a smaller average particle diameter than the depth of the groove of the drill bit, it is easy to be caught in the groove when the drill bit is rotated, thus contributing to the discharge of chips.

  Regarding the particle size of the solid lubricant (B), the average particle size value is more important than the maximum particle size value. This is because the particle size of the solid lubricant having a high ratio in the resin composition affects the hole position accuracy and the lubricity, which are the characteristics of the entry sheet for drilling. Therefore, it is important to manage the average particle size of the solid lubricant (B) in order to improve the performance of the entry sheet for drilling. Therefore, the ratio of the maximum particle size to the particle size distribution of the solid lubricant (B) is high, and it is not preferable to greatly increase the average particle size because the solid lubricity originally expected may be reduced. The solid lubricant (B) has a particle size measurement method in which a sample is dispersed in a solution consisting of a 0.2% hexametaphosphoric acid solution and a few drops of 10% Triton, and a laser diffraction particle size distribution analyzer (model number: SALD-2100, stock) The maximum length of each of the projected solid lubricant (B) particles is measured using Shimadzu Corporation. Then, a particle size distribution curve is calculated. The range of the curve was the particle size of the solid lubricant (B), and the particle size at the maximum content peak of the curve was the average particle size.

In particular, when the solid lubricant (B) is zinc molybdate and molybdenum trioxide, it is not completely insoluble in water, but is non-swellable. For this reason, unlike the swellable solid lubricant, it is not necessary to strictly manage the moisture retention, which is industrially advantageous. Here, the definition of non-swelling property is to stir until an aqueous solution containing 90 parts by weight of water and 10 parts by weight of a solid lubricant is sufficiently mixed, and after standing for 1 hour, measure the sedimentation height of the solid lubricant. The sedimentation height ratio of 90% or more is defined as dispersion or swelling, the sedimentation height ratio of 50% or more but less than 90% is swollen, and the sedimentation height ratio of less than 50% is defined as non-swelling. In the zinc molybdate of the present application, there is an example in which the height to the liquid surface is 66 mm, the top surface of the sedimentation portion of the zinc molybdate is 21 mm, the sedimentation height ratio is 32%, and two layers are clearly separated. Similarly, with the molybdenum trioxide of the present application, the height to the liquid surface is 35 mm, the upper surface of the molybdenum trioxide sedimentation portion is 5 mm, the sedimentation height ratio is 14%, and the molybdenum trioxide sedimentation surface from the upper surface to the liquid surface becomes cloudy. There is an example.
Such characteristics have the following advantages when producing a solution of the water-soluble resin (A). Easy to disperse uniformly and difficult to agglomerate. After drilling, if zinc molybdate or molybdenum trioxide remains in the hole, it is easy to clean. However, when manufacturing the solution of water-soluble resin (A), since the concentration gradient of a solid lubricant (B) arises, it is necessary to stir.

  The hardness of the solid lubricant (B) is unsuitable because, for example, a region exceeding the Mohs hardness of 5 becomes an abrasive. The optimum blending amount of the solid lubricant (B) differs depending on the specification of the printed wiring board to be drilled. Compared to printed wiring board materials that do not contain inorganic fillers, in printed wiring board materials that contain inorganic fillers, wear of drill bits is relatively large, so it is better to blend a large amount of solid lubricant (B). There is also.

  The type of the water-soluble resin (A) is not particularly limited. Examples of the water-soluble resin include polyethylene oxide, polypropylene oxide, sodium polyacrylate, polyacrylamide, polyvinyl pyrrolidone, carboxymethyl cellulose, and polytetramethylene glycol. And at least one selected from the group consisting of polyesters of polyalkylene glycols. Polyester of polyalkylene glycol is a condensate obtained by reacting polyalkylene glycol and dibasic acid. Examples of polyalkylene glycols include polyethylene glycols, polypropylene glycols, polytetramethylene glycols and glycols exemplified by these copolymers, and dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, and pyromellitic. It is preferable to select from partial esters of polyvalent carboxylic acids such as acids, acid anhydrides, and the like. Examples of water-soluble lubricants that are not solid lubricants (B) include polyethylene glycol, polypropylene glycol; polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene Polyoxyethylene monoethers exemplified by nonylphenyl ether, polyoxyethylene octylphenyl ether, etc .; polyoxyethylene monostearate, polyoxyethylene sorbitan monostearate; hexaglycerin monostearate, decahexaglycerin monostearate Examples include polyglycerin monostearates, polyoxyethylene propylene copolymers, etc., and one or more of them are appropriately arranged. It is preferable to and use.

  The thermoplastic water-insoluble resin is not particularly limited, and a known substance can be applied. For example, amide elastomer, butadiene elastomer, ester elastomer, olefin elastomer, urethane elastomer, styrene elastomer, polybutene, low density polyethylene, chlorinated polyethylene, metallocene polyolefin resin, ethylene, acrylic ester, maleic anhydride Copolymer, ethylene / glycidyl (meth) acrylate copolymer, ethylene / vinyl acetate copolymer resin, modified ethylene / vinyl acetate copolymer resin, ethylene / (meth) acrylic acid copolymer resin, ionomer resin, ethylene / (meta ) Acrylic ester copolymer resin and the like are exemplified.

  The water-insoluble lubricant that is not the solid lubricant (B) is not particularly limited, and a known substance can be applied. For example, an amide compound exemplified by ethylene bisstearamide, oleic amide, stearamide, methylene bisstearamide, a fatty acid compound exemplified by lauric acid, stearic acid, palmitic acid, oleic acid, etc. Fatty acid ester compounds exemplified by butyl stearate, butyl oleate, glycol laurate, etc., aliphatic hydrocarbon compounds exemplified by liquid paraffin, polyethylene wax, etc., higher aliphatic alcohols exemplified by oleic alcohol, etc. Is exemplified.

  The thickness of the resin composition layer varies depending on the drill bit diameter used when drilling, the configuration of the copper-clad laminate or multilayer board to be processed, and is usually in the range of 0.02 to 0.3 mm. It is preferable that the thickness is appropriately selected within the range of 0.02 to 0.2 mm. If the thickness of the resin composition layer is less than 0.02 mm, a sufficient lubricating effect cannot be obtained, and the load on the drill bit is increased, and the drill bit may be broken. On the other hand, when the thickness of the resin composition layer exceeds 0.3 mm, the winding of the resin composition around the drill bit may increase.

  In addition, as a method of forming the resin composition layer, a method in which a hot melt or solution of the resin composition is directly applied on the metal supporting foil by a coating method or the like, or is dried in advance. Examples thereof include a hot melt method in which a sheet is prepared and bonded to the metal support foil. At that time, it is preferable to form a resin film (primer layer) in advance on the metal supporting foil so that the metal supporting foil and the resin composition layer are laminated and integrated. Details will be described later.

  Furthermore, when the method of coating and drying the resin composition solution directly on the metal support foil by a coating method or the like is employed, the solution used is a solution containing water and a solvent having a boiling point lower than that of water. It is preferable. The type of the solvent having a boiling point lower than that of water is not particularly limited, and examples thereof include ethanol such as alcohols, methanol and isopropyl alcohol, and low-boiling solvents such as methyl ethyl ketone and acetone can also be used. As other solvents, it is possible to use a solvent obtained by partially mixing tetrahydrofuran or acetonitrile having high compatibility with the resin composition in water or alcohol. The compounding ratio of water and a solvent having a boiling point lower than that of water needs to be in the range of 90/10 to 50/50, preferably in the range of 80/20 to 50/50, and 70/30 to 50/50. Is more preferable, and the range of 60/40 to 50/50 is more preferable. When the blending ratio of the solvent having a boiling point lower than that of water is less than 10, the water-soluble resin (A) may not easily form dense spherulites. When the blending ratio of the solvent having a boiling point lower than that of water exceeds 50, industrial stable production may be hindered.

  Further, when a method of coating and heating and drying a resin composition solution directly on a metal supporting foil by a coating method or a hot melt method, the temperature of the entry sheet for drilling is 120 ° C. to 160 ° C. It is necessary to bring it to room temperature in 5 to 30 seconds from ° C. A high drying temperature exceeding 160 ° C. is not preferable because it may hinder industrial stable production. In addition, a cooling temperature lower than room temperature is not preferable because condensation may occur in a subsequent process.

  The metal support foil used in the entry sheet for drilling according to the present invention is not particularly limited as long as it is a metal material that has high adhesion to the resin composition and can withstand the impact of a drill bit. The thickness of the metal supporting foil is usually 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm. If the thickness of the metal support foil is less than 0.05 mm, burrs of the laminated plate are likely to occur during drilling, and if it exceeds 0.5 mm, it may be difficult to discharge chips generated during drilling. is there. As the metal species of the metal support foil, for example, aluminum can be used. As a material of the aluminum foil, aluminum having a purity of 95% or more is preferable, and examples thereof include 5052, 3004, 3003, 1N30, 1N99, 1050, 1070, 1085, and 8021 defined in JIS-H4160. By using a high-purity aluminum foil for the metal support foil, the impact of the drill bit is reduced and the biting property with the tip of the drill bit is improved, combined with the lubricating effect of the drill bit by the resin composition, The hole position accuracy of the processed hole can be increased. Moreover, it is preferable to use the metal support foil by which the resin film (primer layer) of thickness 0.002-0.02mm was previously formed on the surface from the point of adhesiveness with a resin composition. When blending the solid lubricant (B) into the resin film, the thickness of the resin film is appropriately selected according to the particle size of the solid lubricant (B). The resin used for the resin film is not particularly limited as long as it can improve the adhesion with the resin composition, and either a thermoplastic resin or a thermosetting resin can be used. For example, examples of the thermoplastic resin include urethane polymers, vinyl acetate polymers, vinyl chloride polymers, polyester polymers, acrylic polymers, and copolymers thereof. Examples of the thermosetting resin include resins such as epoxy resins and cyanate resins.

  The entry sheet for drilling of the present invention is used when drilling a printed wiring board material, for example, a copper-clad laminate or a multilayer board. Specifically, an entry sheet for drilling is arranged on the top of one or a plurality of copper-clad laminates or multi-layered plates so that the metal support foil side is in contact with the printed wiring board material. Drilling can be performed from the surface of the composition layer.

  The above description is merely an example of an embodiment of the present invention, and various modifications can be made within the scope of the claims.

  Hereinafter, the effect of the Example of this invention is demonstrated compared with the comparative example which remove | deviates from the scope of the present invention. “Polyethylene glycol” may be abbreviated as “PEG” and “polyethylene oxide” may be abbreviated as “PEO”.

<Example 1>
30 parts by weight of polyethylene oxide having a weight average molecular weight of 150,000 (Altop MG-150 manufactured by Meisei Chemical Co., Ltd.) and 70 parts by weight of polyethylene glycol having a weight average molecular weight of 20,000 (PEG 20000 manufactured by Sanyo Chemical Industries, Ltd.) It was dissolved in a water / MeOH (methanol) mixed solution so that the resin solid content was 30%. The ratio of water and MeOH at this time was 60/40. Further, zinc molybdate (manufactured by Nippon Inorganic Chemical Industry Co., Ltd., particle size 0.4 μm to 13 μm, average particle size 3 μm) as a solid lubricant (B) is added to the water-soluble resin composition solution 100. 5 parts by weight was blended with respect to parts by weight and sufficiently dispersed. Using this water-soluble resin composition solution, a bar coater was used on an aluminum foil (aluminum foil used: 1N30, thickness 0.1 mm, manufactured by Mitsubishi Aluminum Co., Ltd.) on which an epoxy resin film having a thickness of 0.01 mm was formed on one side. The dried water-soluble resin composition layer was applied to a thickness of 0.05 mm, dried in a dryer at 120 ° C. for 5 minutes, cooled to room temperature, and an entry sheet for drilling was prepared. Produced.

<Examples 2 to 14>
A water-soluble resin composition shown in Table 1 was prepared according to Example 1, and an entry sheet for drilling with a water-soluble resin composition layer after drying having a thickness of 0.05 mm was prepared.

<Comparative Examples 1-11>
A water-soluble resin composition shown in Table 1 was prepared according to Example 1, and an entry sheet for drilling with a water-soluble resin composition layer after drying having a thickness of 0.05 mm was prepared.

<Evaluation method>
The following evaluation was performed about each sample of the drill hole entry sheet produced by the Example and the comparative example.
(1) Hole position accuracy After stacking the copper-clad laminates, the drilling entry sheet was placed with the resin composition layer facing upward, and drilling was performed. A drill bit was drilled for 6,000 hits and repeated using four drill bits. For each drill bit, the hole analyzer (model number) shows the difference between the hole position on the back of the bottom plate of the stacked copper clad laminate and the designated coordinates for the holes of 1-1,500 and 1-6,000 hits. : HA-1AM, manufactured by Hitachi Via Mechanics Co., Ltd.), an average value and a standard deviation (σ) were calculated, and “average value + 3σ” was calculated. Furthermore, the average value of “average value + 3σ” for four drill bits was calculated, and the results are shown in Table 1.
As a criterion for determining the hole position accuracy, the hole position accuracy of 1-1,500 hits where drill bit wear has not progressed and the hole position accuracy of 1-6,000 hits where drill bit wear has progressed are determined. When the determination at 1 to 1,500 and 1 to 6,000 hits is “◯”, the overall evaluation is “◯”.
(2) Particle Size Measurement Method for Solid Lubricant (B) The particle size measurement method for solid lubricant (B) is obtained by dispersing a sample in a solution consisting of 0.2% hexametaphosphoric acid solution and a few drops of 10% Triton, and laser diffraction. The maximum length of each of the projected particles of the solid lubricant (B) is measured using a formula particle size distribution measuring device (model number: SALD-2100, manufactured by Shimadzu Corporation). Then, a particle size distribution curve is calculated. The range of the curve was the particle size of the solid lubricant (B), and the particle size at the maximum content peak of the curve was the average particle size.

Composition of water-soluble resin (A):
1) 30 parts by weight of polyethylene oxide (Altop MG-150 manufactured by Meisei Chemical Co., Ltd., Mw = 150,000), 70 parts by weight of polyethylene glycol (PEG 20000, Mw = 20,000 manufactured by Sanyo Chemical Industries, Ltd.), 100 in total Parts by weight.
2) 20 parts by weight of polyether ester (Daiichi Kogyo Seiyaku Co., Ltd., Paogen PP-15, Mw = 100,000), 80 parts by weight of polyethylene glycol (PEG 4000S, Sanyo Chemical Industries, Ltd., Mw = 4,000) 100 parts by weight.
Type of solid lubricant (B):
3) Zinc molybdate (manufactured by Nippon Inorganic Chemical Industry Co., Ltd., particle size 0.4 μm to 13 μm, average particle size 3 μm, layered structure)
4) Molybdenum trioxide (manufactured by Nippon Inorganic Chemical Industry Co., Ltd., particle size 0.7 μm to 55 μm, average particle size 16 μm, columnar structure)
5) Molybdenum disulfide (Daizo Co., Ltd. M-5 powder, particle size 0.5-29 μm, average particle size 5 μm, layered structure)
6) Swelling mica (ME-100 manufactured by Coop Chemical, particle size 5-7 μm, layered structure)
7) Non-swelling mica (Coop Chemical MK-200, particle size 5-8 μm, layered structure)
8) Blending amount of solid lubricant (B) unblended solid lubricant (B):
The solid lubricant (B) is blended with 0, 5, 10, 20, 40, 60, or 80 parts by weight with respect to 100 parts by weight of the resin component of the resin composition.

Drilling conditions:
1) Drill bit diameter: 0.2 mmφ (C-CFU020S manufactured by Tungaloy Co., Ltd.), rotational speed: 200,000 rpm, feed rate 20 μm / rev. , Rising speed: 25.4 m / min, processed substrate is inorganic filler HL832 0.2mmt, Cu12μ, 5 stacked 2) Drill bit diameter: 0.2mmφ (C-CFU020S manufactured by Tungaloy Co., Ltd.), rotating Number: 200,000 rpm, feed rate 20 μm / rev. Ascending speed: 25.4 m / min, processing base material is HL832HS 0.2 mmt with Cu filler, 5 layers, containing inorganic filler

  From the results of Table 1, the samples of Examples 1 to 14 are excellent in the hole position accuracy in both the stage where the wear of the drill bit is not progressing and the stage where the wear is advanced as compared with the samples of Comparative Examples 1-11. I understand that. That is, the zinc molybdate and the molybdenum trioxide of the present invention are remarkably superior in hole position accuracy as compared with the conventional techniques molybdenum disulfide, swellable mica, and non-swellable mica.

  ADVANTAGE OF THE INVENTION According to this invention, compared with the conventional drill hole entry sheet, it can provide the drill hole entry sheet which is excellent in hole position accuracy and reduces breakage of the drill bit.

Claims (11)

  An entry sheet for drilling, in which a layer made of a resin composition is formed on at least one surface of a metal support foil, wherein the resin composition contains at least one of zinc molybdate and molybdenum trioxide as a solid lubricant (B). An entry sheet for drilling, comprising: a resin composition layer having a thickness of 0.02 to 0.3 mm.   The entry sheet for drilling according to claim 1, wherein the resin composition contains a water-soluble resin (A).   The drilling hole according to claim 1, wherein the resin composition contains 1 to 40 parts by weight of the solid lubricant (B) in total with respect to 100 parts by weight of the resin component. Entry sheet.   2. The entry sheet for drilling according to claim 1, wherein the zinc molybdate has an average particle diameter of 1 to 7 μm.   The entry sheet for drilling according to claim 1, wherein the molybdenum trioxide has an average particle size of 3 to 35 µm.   The drill bit entry sheet according to claim 1, which is applied to a drill bit diameter of 0.2 mmφ or less.   The entry sheet for drilling according to claim 1, wherein the metal supporting foil has a thickness in a range of 0.05 to 0.5 mm.   The entry sheet for drilling according to claim 1, further comprising a primer layer as a resin film on the metal supporting foil.   The entry sheet for drilling according to claim 8, wherein the primer layer contains the solid lubricant (B).   The drill drilling entry according to claim 9, wherein the amount of the solid lubricant (B) in the primer layer is 1 to 20 parts by weight per 100 parts by weight of the primer composition. Sheet.   The entry sheet for drilling according to claim 1, which is used for processing a copper-clad laminate or a multilayer board.