KR101619749B1 - Drill hole entry sheet - Google Patents

Abstract

A layer made of a crystalline water-soluble resin composition and having a thickness of 0.02 to 0.3 mm is formed on at least one surface of the metal support foil and the hole position accuracy is excellent and the resin is not adhered to the drill bit, , And a puncture entry sheet. Wherein the grain size of the water-soluble resin composition is in the range of 5 to 70 占 퐉, the standard deviation thereof is 25 占 퐉 or less, the surface roughness Sm of the drill bit entry face of the layer made of the water- And the layer is formed by applying a solution containing the water-soluble resin composition directly onto the metal support foil, followed by drying and drying the solution containing the water-soluble resin composition, and then drying the solution at a temperature of 120 ° C to 160 ° C At a cooling rate of 1.5 占 폚 / sec or more at a temperature of 25 占 폚 to 40 占 폚 within 60 seconds from the temperature.

Description

{DRILL HOLE ENTRY SHEET}

The present invention relates to a perforated entry sheet used in perforation of copper-clad laminate or multilayer boards.

As a method of perforating a copper clad laminate or a multilayer board used for a printed wiring board material, a copper clad laminate or a multilayer board may be laminated one or several sheets, and an uppermost portion of the copper clad laminate may be used as an entry and backup board, Or a sheet in which a resin composition layer is formed on the surface of a metal support foil (hereinafter, this sheet is referred to as a "perforation entry sheet" in the present specification) is disposed and punched.

In recent years, as a demand for a copper clad laminate or a multilayer plate which is a material of a printed wiring board, there has been demanded a high-quality perforation process with high density, improved productivity and cost reduction, and improved hole position accuracy. In order to cope with this demand, for example, in Patent Document 1, a perforating process using a sheet made of a water-soluble resin such as polyethylene glycol has been proposed. In Patent Document 2, a lubricant sheet having a water-soluble resin layer formed on a metal foil has been proposed. Patent Document 3 proposes a perforated entry sheet in which a water-soluble resin layer is formed on an aluminum foil on which a thin film of a thermosetting resin is formed.

However, in comparison with the progress of the technology for increasing the density of semiconductors, the advancement of the technology for increasing the density of printed wiring boards is slow and there is a gap between them, so that the demand for higher density for printed wiring board materials is further improved. In order to cope with this demand, it is necessary to further improve the hole position accuracy, and development of a perforated entry sheet having more excellent hole position accuracy is urgently required.

In addition, in order to increase competition and demand for emerging countries due to globalization, productivity improvement and cost reduction are required more strongly than ever. Therefore, it is urgently required to develop a perforated entry sheet having an improved hole position accuracy so as to further improve the hole position accuracy and increase the number of stacked sheets that can be perforated at one time.

Japanese Patent Application Laid-Open No. 4-92494 Japanese Patent Laid-Open No. 5-169400 Japanese Patent Application Laid-Open No. 2003-136485

The demand for a copper-clad laminate or a multilayer plate as a material of a printed wiring board is as follows. High density, productivity and cost reduction are demanded. Specifically, as described below, the hole- Is required.

First, the increase in the density of the printed wiring board is simply expressed as a change in the minimum hole diameter. In mass production, diameter reduction progresses to 0.3 mm, 0.25 mm, and 0.2 mm, and 0.15 mm and 0.105 mm are drilled. However, laser perforations are employed for those having the smallest hole diameters of 0.08 mm, 0.075 mm, 0.06 mm, and 0.05 mm, respectively. The reason for this is that breakage of the extremely small diameter drill bit is apt to occur in a conventional bore entry sheet because the extremely small diameter drill bit made of a hard metal is easily broken and fragile. In the region of the minimum diameter, it has not been solved by the prior art to prevent breakage of the drill bit and to drill with a high position accuracy.

Secondly, the drill bit attached to the resin may cause a center runout as a result of the center being displaced from its axis during rotation, thereby reducing the accuracy of the drilling position. The drill bit of the smallest diameter is apt to centerly oscillate by winding a small amount of resin together. In addition, when the drop position and the drilling position of the resin are the same, the drill bit comes into contact with the fallen resin to deteriorate the centripetal property and cause deterioration of the hole position accuracy or drill bit breakage. Therefore, in the extremely small diameter drill bit, it is necessary to greatly reduce the resin wound around the drill bit. However, since the spiral groove for discharging the cutting material is thin and shallow in the drill bit of the smallest diameter, Could not be resolved. On the other hand, the aperture refers to the straightness in the cutting direction at the time of cutting.

Third, when the drill bit is brought into contact with the resin composition layer of the entry sheet, the cutting edge at the leading end is slid into the resin composition layer while sliding. Here, sliding is a very small diameter drill bit for achieving high density and detrimental to centrifugal force. Therefore, it is important to improve the hole position accuracy by reducing the amount of sliding motion. However, the drill bit of a very small diameter is subjected to a sliding motion under the influence of a slight difference in the surface state of the resin composition layer. When the amount of the sliding motion is large, the drill bit is also broken. It has not been possible to solve the problem of improving the hole position accuracy while reducing the amount of sliding motion in the prior art.

Fourth, regardless of drill bit diameter, there is a market demand for productivity improvement and cost reduction. In the background, there is a desire to intensify competition due to globalization, to bring demand for emerging countries, and to reduce equipment inventory. In addition, the increase in the number of holes and the increase in the number of holes make the drilling processing time longer, and competition with the laser drilling technique is also a driving force for improving the productivity and reducing the cost. For example, with globalization, low cost manufacturing in countries with different cost structures is creating intense competition, and cheaper costs are needed to fill demand in emerging economies with significantly lower import levels. In other words, there is a great difference between the market demand for productivity improvement and cost reduction, and it is necessary to increase the number of stacked layers of the copper-clad laminate and the multilayer plate which can be drilled at one time by improving the hole position accuracy. It has been required to reduce the cost by reducing the investment amount of the drilling machine. However, it has not been solved by the prior art that both the cost and the number of stacked layers, which are much more stringent than the conventional one, are compatible. The increase in the number of lamination means that both the uppermost and lowermost hole positional accuracy of the laminated copper-clad laminate and the multilayer laminate is maintained at a satisfactory level, and lamination of the copper clad laminate and the multilayer laminate is carried out to the extent that the drill bit blade length permits .

In order to solve the above problems, an object of the present invention is to provide a perforated entry sheet which prevents drill bit breakage, is excellent in hole position accuracy, and is less likely to adhere resin to a drill bit, as compared with a conventional perforated entry sheet.

The inventors of the present invention have made various studies to solve the above problems and found that the surface state of the resin composition layer on the entrance face of the drill bit, in particular, the average particle diameter and the standard deviation of the crystal grain of the water- It is noted that the surface roughness Sm (average interval of concave and convex) of the bit entry surface is important. By specifying the cooling conditions at the time of production, it is possible to control the crystallinity of the water-soluble resin composition. As a result, it is possible to produce a large number of dense crystals having small crystal grains and small standard deviation, . As a result, it is possible to increase the perceptibility of the drill bit, to drill the drill bit at a very small diameter with high positional accuracy, and to reduce the resin wound around the drill bit, thereby reducing drill bit breakage.

The present invention has been made based on these results, and its gist is as follows.

(1) A perforated entry sheet made of a crystalline water-soluble resin composition and having a thickness of 0.02 to 0.3 mm formed on at least one surface of the metal support foil, wherein the grain size of the water-soluble resin composition is in the range of 5 to 70 μm , The standard deviation of the water-soluble resin composition is 25 占 퐉 or less, the surface roughness (Sm) of the drill bit entry face of the layer made of the water-soluble resin composition is 8 占 퐉 or less, , Directly after applying the above-mentioned water-soluble resin composition, or after applying a solution containing the water-soluble resin composition and drying it, drying the solution at a temperature of from 25 ° C to 40 ° C At a cooling rate of 1.5 DEG C / sec or more.

(2) The grain size of the water-soluble resin composition is in the range of 5 to 40 占 퐉 and the standard deviation thereof is 17 占 퐉 or less. The layer made of the water-soluble resin composition has a surface roughness Sm ) Is not larger than 7 占 퐉.

(3) The water-soluble resin composition contains a water-soluble resin (A) and further contains a hydrophobic substance (B1), a substance (B2) having a melting point higher than that of the water-soluble resin (A) (B3), and the material (B3) for increasing the thickness of the punched entry sheet.

(4) The perforated entry sheet according to (1) above, wherein the solution containing the water-soluble resin composition further contains water and a solvent having a lower boiling point than water.

(5) The perforated entry sheet according to (1), wherein the metal support foil has a thickness of 0.05 to 0.5 mm.

(6) The perforated entry sheet according to the above (1), which is used for processing a copper-clad laminate.

The perforated entry sheet of the present invention can produce a large number of dense crystals having a small grain size of the water-soluble resin composition layer and having a small standard deviation and also reduce the surface roughness (Sm), thereby improving the perforation of the drill bit, As a result, drilling bit can be drastically reduced at the time of drilling. As a result, it is possible to perform high-quality boring with excellent productivity.

Fig. 1 is an enlarged photograph of the surface state of the water-soluble resin composition layers of each of Examples and Comparative Examples. Fig.
2 is a schematic cross-sectional view showing a state in which a drilling process is performed using a conventional perforated entry sheet.
3 is a schematic cross-sectional view showing a state in which a drilling entry sheet according to the present invention is used for drilling.
4 is a graph showing the relationship between the average particle diameter of the crystal grains of the water-soluble resin composition layer and the hole position accuracy for each of the Examples and Comparative Examples.
5 is a graph showing the relationship between the standard deviation of the crystal grain size of the water-soluble resin composition layer and the hole position accuracy for each of the Examples and Comparative Examples.
Fig. 6 is a graph showing the relationship between the surface roughness (Sm) of the water-soluble resin composition layer and the hole position accuracy for each of the examples and comparative examples.

The perforated entry sheet of the present invention is a perforated entry sheet in which a layer made of a water-soluble resin composition having crystallinity (hereinafter referred to as " water-soluble resin composition layer ") is formed on at least one surface of a metal support foil.

In the perforated entry sheet according to the present invention, crystal grains having a particle size within a specific range and a standard deviation in a specific range are present on the surface of the entry sheet, and the drill bit entry surface is a surface As the roughness Sm is provided, it can contribute to improvement of the hole position accuracy at the time of drilling, reduction of winding of the resin, and prevention of breakage of the drill bit.

The average particle diameter of the crystal grains of the water-soluble resin composition is required to be in the range of 5 to 70 占 퐉, preferably in the range of 5 to 50 占 퐉, and preferably in the range of 5 to 40 占 퐉 More preferably in the range of 5 to 30 占 퐉, particularly preferably in the range of 5 to 20 占 퐉, and most preferably in the range of 5 to 10 占 퐉. When the average grain size of the crystal grains is less than 5 mu m, the surface of the water-soluble resin composition becomes too uniform so that the cutting edge at the tip of the drill bit slides and the biting performance against the surface of the entry sheet decreases, As a result, it has been found through experimentation that the effect of improving the hole position accuracy by reducing the crystal grain is not obtained. On the other hand, in the case of exceeding 70 mu m, it has been found in the experiments that the entry of the drill bit into the surface of the entry sheet is affected by the irregularities of the crystal grains, thereby deteriorating the aperture.

Here, FIG. 2 is a diagram schematically showing a state in which a drilling process is performed using a conventional drilling entry sheet, and FIG. 3 is a schematic view showing the drilling process using the drilling entry sheet according to the present invention, Fig. As shown in Fig. 3, when the water-soluble resin composition layer 2 according to the present invention is used, the average particle diameter of the crystal grains 2a to 2g constituting the water-soluble resin composition layer 2 corresponding to the size of the drill bit tip 1 The drill bit front end 1 and the water-soluble resin composition layer 2 are favorably biteable, so that the hole position accuracy can be improved. On the other hand, in the case of using the conventional resin composition layer 20, as shown in Fig. 2, the grains 20a to 20c constituting the resin composition layer 20 are larger than the size of the drill bit tip 1 The tip of the drill bit 1 may cause slipping or the like on the surface of each of the crystal grains 20a to 20c so that the tip of the drill bit is disturbed and the accuracy of the hole position is deteriorated.

Herein, the grain size (hereinafter also referred to as " crystal grain size ") of the grain size of the water-soluble resin composition in the present invention means the grain size of the crystal grains existing on the surface of the water- .

As a method of measuring the average value of the grain size of the water-soluble resin composition, the surface of the resin composition layer of the perforated entry sheet was measured with a V-LASER microscope (product number VK-9700, KEYENCE CORPORATION) And the average diameter (number average) of the 50 diameters of arbitrarily selected crystal grains is measured by the same microscope to obtain the average grain diameter of the water-soluble resin composition. On the other hand, in the present invention, crystal grain size is calculated to be less than 1 탆.

In order to improve the hole position accuracy at the time of drilling, it is necessary to optimize the grain size of the grain of the water-soluble resin composition, and at the same time, the standard deviation of the average grain size of the grain must be 25 탆 or less, More preferably not more than 17 mu m, further preferably not more than 15 mu m, particularly preferably not more than 10 mu m, most preferably not more than 5 mu m. The reason for limiting the standard deviation is to find a threshold in the experiment. When the standard deviation of the crystal grain size is smaller than 25 占 퐉 even though the average grain size is small, large diameter particles are scattered, This is because worrying of positional accuracy is worrisome.

The method of calculating the standard deviation of the average grain size of the water-soluble resin composition is as follows. The surface of the resin composition layer of the perforated entry sheet is measured with a V-LASER microscope (product number VK-9700, KEYENCE CORPORATION) And the maximum diameters of 50 crystal grains arbitrarily selected are measured with the same microscope, and the average value is calculated. Then, the standard deviation of the maximum diameters of the 50 measured crystal grains can be calculated.

In the layer made of the water-soluble resin composition, the surface roughness of the entrance face of the drill bit, more specifically, the mean spacing Sm of irregularities defined in JIS-B0601-1994 is 8 탆 or less, More preferably at most 6 mu m, further preferably at most 5 mu m, most preferably at most 4 mu m. In the experiment, if the thickness exceeds 8 탆, entry of the drill bit into the entry sheet surface is affected by the irregularities of the surface, thereby deteriorating the aperture, which may cause deterioration of hole position accuracy.

As for the method of obtaining the surface roughness (Sm) of the water-soluble resin composition layer, the surface of the resin composition layer was observed with a V-LASER microscope (product number VK-9700, KEYENCE CORPORATION) (Face tilt correction and automatic correction of the height range) are carried out, and the surface roughness (JIS-B0601: 1994 linearity) of an evaluation length of 500 mu m in an arbitrary direction in the observation image is measured. Five measurements of the same measurement from the same observation image, and the average value thereof can be made to be Sm.

The water-soluble resin composition layer used in the perforated entry sheet of the present invention can be produced by a method of directly applying a heat-soluble product of a water-soluble resin composition on the metal support foil and cooling the solution, or a method of cooling the solution containing the water- Or the like, followed by drying and cooling.

The water-soluble resin composition used in the perforated entry sheet of the present invention is a composition containing a water-soluble resin (A) and has crystallinity. Specifically, a mixture of the water-soluble resin (A) and another substance is exemplified. Examples of the other materials include various inorganic compounds, organic compounds, mixtures, complexes, complexes, low molecular substances, monomers, oligomers, polymers, polymers, natural resins, fibers, minerals, hydrophobic materials and hydrophilic materials.

The kind of the water-soluble resin (A) is not particularly limited as long as it is a water-soluble resin having crystallinity, but it is preferably a water-soluble resin having a high crystallinity. Examples thereof include polyalkylene oxide, sodium polyacrylate, , Carboxymethylcellulose, polytetramethylene glycol, and polyesters of polyalkylene glycol. It is preferable that at least one selected from the group consisting of polyvinyl alcohol,

Examples of the polyalkylene oxide include polyethylene oxide, polypropylene oxide and the like. Further, polyethylene oxide which does not cause steric hindrance in the molecular structure is more preferable. Polyester of polyalkylene glycol is a condensate obtained by reacting polyalkylene glycol with dibasic acid. Examples of polyalkylene glycols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and glycols exemplified as copolymers thereof. As the dibasic acids, partial esters of polyvalent carboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, sebacic acid and pyromellitic acid, acid anhydrides and the like are preferable. Further, a condensate containing polyethylene glycol as a main chain which does not cause steric hindrance in the molecular structure is more preferable.

The water-soluble resin composition of the present invention is a water-soluble resin composition comprising a water-soluble resin (A), a hydrophobic substance (B1), a substance (B2) having a melting point higher than that of the water-soluble resin (A) And a material (B3) for increasing the heat resistance of the substrate.

When the hydrophobic substance (B1) is dispersed in the water-soluble resin composition and the water-soluble resin composition is solidified by cooling by mixing the hydrophobic substance (B1) with the water-soluble resin composition, the hydrophobic substance (B1) And a large number of crystal grains of the water-soluble resin composition can be precipitated in small quantities.

By mixing the water-soluble resin composition with the substance (B2) having a melting point higher than that of the water-soluble resin (A), it is possible to cause a difference in solidification rate when the water-soluble resin composition is solidified by cooling. That is, the action of solidifying the substance (B2) having a high melting point at a rapid timing functions as nuclei for crystal formation, and a large number of crystal grains of the water-soluble resin composition can be precipitated in small quantities. Among the substance (B2) having a higher melting point than the water-soluble resin (A), there is a substance which not only reduces the grain size but also has a high effect of reducing the surface roughness (Sm) of the water-soluble resin composition layer.

The water-soluble resin (A) is mixed with a substance (B3) which improves the compatibility of the solvent with the water-soluble resin composition so that the hydroxyl group contained in the molecular structure of (B3) Therefore, when the water-soluble resin composition is solidified by drying and cooling, a large number of crystal grains can be produced in small quantities. In addition, among the substances (B3) that improve the compatibility between the water-soluble resin (A) and the solvent, there is a substance which not only reduces the grain size but also has a high effect of reducing the surface roughness (Sm) of the water-soluble resin composition layer.

Although the hydrophobic substance (B1), the substance (B2) having a higher melting point than the water-soluble resin (A), and the substance (B3) that improves the compatibility of the water-soluble resin (A) with the solvent are all composed of a single substance Or may be composed of a mixture of two or more kinds. It is also possible to use the hydrophobic substance (B1), the substance (B2) having a higher melting point than the water-soluble resin (A), and the substance (B3) which improves the compatibility of the water-soluble resin (A) with the solvent.

The hydrophobic substance (B1), the substance B2 having a higher melting point than the water-soluble resin (A), and the substance (B3) that improves the compatibility of the water-soluble resin (A) 0.1 to 5 parts by weight, preferably 0.1 to 3 parts by weight, more preferably 0.2 to 3 parts by weight, more preferably 0.2 to 2 parts by weight, Particularly preferred is a combination of parts by weight. If the amount is less than 0.1 part by weight, it may be difficult to exhibit the effect of producing a dense crystal, while if it exceeds 5 parts by weight, there is no economical rationality. It is reasonable to select the substances (B1, B2, B3) which exhibit a small effect.

Here, the hydrophobic substance (B1) is not particularly limited as long as it is hydrophobic. For example, hydrophobic polymers, long-chain alcohols, hydrophobic polysaccharides and inorganic compounds can be used. Specific examples of the thermoplastic polymer include polymers such as urethane, silicone and acrylic polymers and copolymers thereof, polyetherimide, polyimide, polyvinyl chloride-vinyl acetate, polyamides, polypropylene, polyvinyl acetate, polybutene, Examples of the thermosetting polymer include powders and fine particles such as polymethacrylamide, powdered cellulose, cellulose derivatives, polyvinyl ether, phenoxy resin, ethylene-vinyl alcohol copolymer resin and polytetrafluoroethylene. , A powder or a fine particle such as a phenol resin, a urea resin, an acrylic resin, a polyethylene glycol dimethacrylate resin, a bismaleimide resin, a bismaleimide triazine resin, a cyanate resin, a benzoguanamine resin, As the family, lauryl alcohol, cetanol, stearyl alcohol, oleyl alcohol, Linolyl alcohol, and the like. Examples of inorganic compounds include talc, molybdenum disulfide, zinc molybdate, graphite, tungsten disulfide, fluorinated graphite, boron nitride and the like. Or more can be appropriately mixed and used. As the hydrophobic substance (B1) for enhancing the effect of the present invention, stearyl alcohol, zinc molybdate, graphite, boron nitride and the like are more preferable. This is because they have a high dispersibility with respect to the water-soluble resin composition solution.

The material (B2) having a melting point higher than that of the water-soluble resin (A) is not particularly limited as long as the melting point is higher than that of the resin (A). For example, amino acids, organic acids, organic acid salts, organic salts, organic phosphates, polysaccharides, rosins and inorganic compounds can be used. Specific examples of the amino acids include sodium glutamate. Examples of the organic acids include malic acid, malonic acid, succinic acid, fumaric acid, maleic acid and cyanuric acid. Examples of the organic acid salts include malic acid, malonic acid, And metal salts of organic acids such as succinic acid, fumaric acid, maleic acid, formic acid, acetic acid, propionic acid, stearic acid and cyanuric acid. Examples of the organic salts include melamine cyanurate and the like. Triclosan sodium salt and the like. Examples of the polysaccharide include cellulose, chitin, starch, glycogen, agarose and pectin. Examples of the rosin include tall rosin, tall rosin fatty acid ), And the like. Examples of inorganic compounds include sodium chloride, sodium sulfate, and magnesium sulfate. Further, sodium glutamate, sodium formate, sodium formate, calcium formate, sodium stearate, calcium stearate, cellulose and the like are more preferable as the substance (B2) having a melting point higher than that of the water-soluble resin (A)

Examples of the substance (B3) that improves the compatibility of the water-soluble resin (A) with the solvent include polyhydric alcohols, sugar alcohols, amino acid derivative alcohols and the like having a hydroxy group in its molecular structure. As the polyhydric alcohol, polymers such as polyethylene glycol contained in the water-soluble resin (A) are excluded, but polyhydric alcohols other than the polymer include trimethylolpropane, pentaerythritol, neopentyl glycol, trimethylolethane and the like, Include sorbitol, xylitol, and inositol. Amino acid derivative alcohols include oxyaniline, oxytoluidine, tyrosine, amino deoxy sugar, and the like. Further, pentaerythritol, sorbitol, xylitol, inositol and the like are more preferable as the substance (B3) for enhancing the compatibility of the water-soluble resin (A) and the solvent for enhancing the effect of the present invention.

The thickness of the water-soluble resin composition layer varies depending on the diameter of the drill bit used in the punching process, the configuration of the copper clad laminate or the multilayer plate to be processed, and is usually in the range of 0.02 to 0.3 mm and in the range of 0.02 to 0.2 mm desirable. If the thickness of the water-soluble resin composition layer is less than 0.02 mm, a sufficient lubrication effect can not be obtained, and the load on the drill bit becomes large, which may cause breakage of the drill bit. On the other hand, if the thickness of the water-soluble resin composition layer exceeds 0.3 mm, the winding of the resin on the drill bit may increase.

When a solution containing the water-soluble resin composition is coated directly on the metal support foil by a coating method or the like, the solution used is preferably water and water having a boiling point lower than that of water (more preferably 15 deg. C Or lower) solvent. Examples of the solvent having a lower boiling point than water include, but are not limited to, ethanol, such as alcohol, methanol or isopropyl alcohol, and a low boiling point solvent such as methyl ethyl ketone or acetone.

By containing a solvent having a boiling point lower than that of the water, it contributes to reduction of grain size of crystal grains and reduction of surface roughness (Sm), thereby improving hole position accuracy. Each of the solvents is characterized in that ethanol reduces grain size of crystal grains and methyl ethyl ketone contributes to reduction of surface roughness (Sm). Ethanol has a high effect of improving the hole position accuracy. As a low boiling point solvent, ethanol and acetone are more preferable. In general, increasing the blending amount of the low-boiling solvent contributes to reduction of grain size of grain, reduction of surface roughness (Sm), and reduction of standard deviation of grain size. However, if the blending amount of the low boiling point solvent is continuously increased, the effect of improving the hole position accuracy is gradually saturated. Further, when the boiling point of the low boiling point solvent is less than 15 ° C, it is difficult to exhibit the effect.

The mixing ratio of the water and the solvent having a boiling point lower than water should be in the range of 90/10 to 50/50 and preferably in the range of 80/20 to 50/50 and in the range of 70/30 to 50/50 Is most preferable. When the blending ratio of the solvent having a lower boiling point than water is less than 10, it may be difficult to exhibit a dense crystal-forming effect. When the compounding ratio of the solvent having a lower boiling point than water is more than 50, there is no economical rationality and there is a fear that the industrial stable production may be hindered.

The method of manufacturing the entry sheet is not particularly limited in the case of employing a method of directly applying the heat-soluble material of the water-soluble resin composition onto the metal support foil and coating and cooling the same.

The water-soluble resin composition may be kneaded by a conventional kneading means, for example, a biaxial roll, a mixer, a dual arm kneader, a plunger extruder, Or the like is preferably used. Further, when kneading the water-soluble resin composition, kneading is preferably performed in a nitrogen atmosphere in order to suppress decomposition of the water-soluble resin composition. In order to uniformly disperse the water-soluble resin composition, it is preferable to knead the water-soluble resin composition at a temperature of 120 ° C to 160 ° C. If the kneading temperature is lower than 120 ° C, the water-soluble resin composition may become uneven and adversely affect properties such as appearance and hole position accuracy. If it exceeds 160 ° C, the water-soluble resin composition may be decomposed, It may adversely affect characteristics such as accuracy.

The method of coating the water-soluble resin composition directly on the metal support foil is not particularly limited.

A general coating apparatus may be used, and it is preferable to use, for example, a knife coater, an extrusion coater, a die coater, a curtain coater, or the like. When the thickness of the water-soluble resin composition layer is not uniform, it is preferable to uniformly coat the heat-soluble material of the water-soluble resin composition using the above coater because the properties such as hole position accuracy may be adversely affected.

When a method of directly coating, drying and cooling the solution containing the water-soluble resin composition onto the metal support foil by the coating method or the like is employed, the coating method of the entry sheet is not particularly limited, and a general coating apparatus It may be used. For example, gravure coater, roll coater, knife coater, extrusion coater, die coater, curtain coater or the like is preferably used as coating means for making the thickness of the water-soluble resin composition layer uniform. When the thickness of the water-soluble resin composition layer is not uniform, there is a possibility that the properties such as the hole position accuracy may be adversely affected. Therefore, it is preferable to uniformly coat the solution of the water-soluble resin composition using the above method.

It is also preferable that the solution of the water-soluble resin composition is directly applied onto the metal support foil and then the water-soluble resin composition solution is dried, so that it is optimized according to the thickness and water content of the water-soluble resin composition layer.

Concretely, it is necessary to keep the temperature at 120 to 160 ° C for 10 seconds to 600 seconds, and it is preferable to dry at 120 to 160 ° C for 10 seconds to 500 seconds, It is more preferable to maintain the temperature at 120 to 160 ° C for 15 seconds to 400 seconds and to dry at 120 to 150 ° C for 20 seconds to 300 seconds. When the drying temperature is less than 120 ° C or the holding time at the drying temperature is less than 10 seconds, the solvent may remain in the water-soluble resin composition layer or the amount of heat required to melt the water-soluble resin composition may be insufficient , There is a possibility of being a non-uniform water-soluble resin composition layer. On the other hand, when the drying temperature is higher than 200 ° C or when the holding time exceeds 600 seconds, the water-soluble resin composition may be decomposed to cause a problem in appearance.

When the solution of the water-soluble resin composition is coated on the metal support foil and dried, it is preferable that the concentration of the solvent remaining in the water-soluble resin composition layer obtained after drying is less than 5%.

Incidentally, in order to produce dense crystals in the resin composition layer, ultrasonic vibration or vacuum drying may be used in combination.

With respect to the conditions for cooling the water-soluble resin composition, since the cooling rate of the prior art is less than 1.2 DEG C / sec, the grain size of the crystal grains is large and the standard deviation and the surface roughness (Sm) There was a problem in accuracy, winding of resin and the like. Therefore, as the cooling conditions in the present invention, it is necessary to cool the material from a cooling start temperature of 120 ° C to 160 ° C, and a cooling end temperature of 25 ° C to 40 ° C within 60 seconds at a cooling rate of 1.5 ° C / second or more.

When the cooling termination temperature exceeds 40 캜, small curing and homogenization of the crystal grains, which is a feature of the present invention, can not be achieved. Likewise, even when the cooling time exceeds 60 seconds, small-scale curing and homogenization of the crystal grain, which is a feature of the present invention, can not be achieved. On the other hand, when the cooling termination temperature is lower than 15 캜, warpage occurs in the entry sheet and condensation occurs in the subsequent process, which is not preferable. If the cooling rate is less than 1.5 캜 / second, the cooling time may become longer and may exceed 60 seconds, which is not preferable.

It is preferable that the cooling is performed at a temperature of 120 to 160 캜 and at a temperature of 25 to 40 캜 and at a cooling rate of 2 캜 per second or more within 50 seconds from the viewpoint of obtaining a higher effect of small- More preferably at a temperature of 120 to 160 ° C. and at a temperature of 25 to 40 ° C. within 40 seconds and at a cooling rate of 2.5 ° C./sec or more and more preferably at a temperature of 120 to 160 ° C. and at a temperature of 25 to 40 ° C. More preferably at a cooling rate of 3 DEG C / sec or more within 30 seconds, and at a cooling rate of 4.5 DEG C / sec or more within 20 seconds at a temperature of 120 DEG C to 160 DEG C and a temperature of 25 DEG C to 40 DEG C And most preferably cooled at a temperature of 120 ° C to 160 ° C at a temperature of 25 ° C to 40 ° C and at a cooling rate of 6 ° C / second or more within 15 seconds.

The metal support foil used in the perforated entry sheet of the present invention is not particularly limited as long as the metal support foil has high adhesion with the water-soluble resin composition and can withstand impacts caused by drill bits. As the metal species of the metal support foil, for example, aluminum can be used, and the thickness of the metal support foil is usually 0.05 to 0.5 mm, preferably 0.05 to 0.3 mm. When the thickness of the aluminum foil is less than 0.05 mm, burrs of the laminated board tend to occur at the time of drilling. If the thickness of the aluminum foil is more than 0.5 mm, it may be difficult to discharge the cutting powder which occurs at the time of drilling. As the material of the aluminum foil, aluminum having a purity of 95% or more is preferable, and specifically, 5052, 3004, 3003, 1N30, 1N99, 1050, 1070, 1085, 1100, 8021 and the like specified in JIS-H4100, H4160 and H4170 . By using a high-purity aluminum foil as the metal support foil, the impact on the drill bit and the bite with the drill bit tip are improved, and the lubrication effect of the water-soluble resin composition interacts with each other, .

From the viewpoint of adhesiveness with the water-soluble resin composition, it is preferable to use an aluminum foil having a resin coating on the surface in advance of 0.001 to 0.02 mm in thickness. The thickness of the resin coating is more preferably 0.001 to 0.15 mm, To 0.1 mm is particularly preferable. The resin used for the resin coating is not particularly limited as long as it can improve the adhesion with the water-soluble resin composition, and any of thermoplastic resin and thermosetting resin can be used. Examples of the thermoplastic resin include urethane-based, vinyl acetate-based, vinyl chloride-based, polyester-based, and copolymers thereof. Examples of the thermosetting resin include epoxy-based resins and cyanate-based resins. Further, in the present invention, as the metal supporting foil, it is also possible to use a commercially available metal foil coated with a resin in advance by a known method.

The perforated entry sheet of the present invention is used for drilling a printed wiring material, for example, a copper clad laminate or a multilayer plate. Concretely, the copper clad laminate or the multilayer plate is placed on the uppermost surface of a laminate of one or more sheets so that the metal supporting foil side is in contact with the printed wiring material, and from the surface of the water-borne resin composition layer of the perforated entry sheet, Can be performed.

Example

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. It should be noted that the following embodiments are merely illustrative of the embodiments of the present invention, and the present invention is not limited thereto. Further, in this embodiment, "polyethylene glycol" is abbreviated as "PEG" and "polyethylene oxide" is abbreviated as "PEO" in some cases.

Table 1 shows specifications of the resins, solvents, additives and metal support foils used in the production of perforated entry sheets of Examples and Comparative Examples, and cooling conditions, and also shows the drill bit The condition of diameter is shown.

≪ Example 1 >

80 parts by weight of polyethylene oxide (ALTOP MG-150, manufactured by Meisei Chemical Works, Ltd.) having a number average molecular weight of 150,000 and 20 parts by weight of polyethylene glycol (PEG20000, manufactured by Sanyo Chemical Industries, Ltd.) , ≪ / RTI > Further, 0.5 part by weight of sodium formate (manufactured by Mitsubishi Gas Chemical Company, Inc.) was added to the solid content of the water-soluble resin mixture to completely dissolve it. A solution of this water-soluble resin composition was applied to a surface of an aluminum foil (used aluminum foil: 1100, thickness 0.07 mm, manufactured by Mitsubishi Gas Chemical Company, Inc.) on which an epoxy resin film having a thickness of 0.01 mm was formed, And dried at 120 DEG C for 3 minutes and further cooled at a cooling rate of 3.1 DEG C / second to prepare a perforated entry sheet (see Table 2).

Six sheets of copper laminated sheets (CCL-HL832HS, copper foil on both sides, 5 mu m, manufactured by Mitsubishi Gas Chemical Company, Inc.) having a thickness of 0.1 mm were laminated on the obtained perforated entry sheet, A drill bit (a KMC L518A 0.105 x 1.8, manufactured by Union Tool Co.), a number of revolutions of 330,000 rpm, and a feed rate of 8 mu m / rev were placed on the lower side of the laminated plate, 20 holes were drilled at 3,000 hits per piece (see Table 2).

Table 3 shows the results of the average grain size (占 퐉), the grain size standard deviation (占 퐉) and the surface roughness Sm (占 퐉) of the grain size of the water-soluble resin composition.

≪ Examples 2 to 20 and Comparative Examples 1 to 36 >

Examples 2 to 20 and Comparative Examples 1 to 36 were prepared in the same manner as in Example 1 except that the water-soluble resin compositions shown in Table 1 and Table 2 were prepared and coated on an aluminum foil, dried and cooled to prepare a perforated entry sheet, And punching was performed.

For example, in Example 2, 80 parts by weight of polyethylene oxide (ALTOP MG150, manufactured by Meisei Chemical Works, Ltd.) having a number average molecular weight of 150,000 and 20 parts by weight of polyethylene glycol (PEG20000, manufactured by Sanyo Chemical Industries, Ltd.) Was dissolved in a water / MeOH (methanol) mixed solution so that the resin solid content became 30%. At this time, the ratio of water to MeOH is 90 parts by weight / 10 parts by weight. As described above, there is an example in which a low boiling point solvent having a lower boiling point than water is used.

On the other hand, Comparative Example 26 is commercially available "LX120" manufactured by Sang-A Flontec Co., Ltd. Comparative Example 27 is commercially available "AL-100040" manufactured by Yong Li Chuan Industrial Co., Ltd. Comparative Example 29 is commercially available Uniplus Electronics Co., Ltd. "LAE-1007" was used.

Table 3 shows the results of the average grain size (占 퐉), the grain size standard deviation (占 퐉) and the surface roughness Sm (占 퐉) of the grain size of the water-soluble resin composition. 1 shows the surface state of the water-soluble resin composition layer for specific samples (Examples 2, 3, 10, 12 and 19 and Comparative Examples 2, 10, 20, 26 and 28) in an enlarged scale.

<Evaluation method>

The following evaluation was performed on each sample of the perforated entry sheet produced in the examples and the comparative examples.

(Drilling processing)

In order to evaluate each of the obtained samples, a drilling process was performed under the following conditions.

For drilling with a drill bit diameter of 0.15 mmφ, four copper laminated plates (CCL-HL832, copper foil 12 μm, made by Mitsubishi Gas Chemical Company, Inc.) having a thickness of 0.2 mm were laminated and a layer of the water- (NEU L004 0.15x2.5 made by Union Tool Co.), the number of revolutions: 200,000 rpm, the feed rate: 20 占 퐉, and the thickness of the laminated plate was set at the lower side of the laminated copper- / rev., 20 holes were drilled at 3,000 hits per drill bit.

Perforation of the drill bit diameter 0.105 mmφ was carried out by laying six layers of a copper clad laminate (CCL-HL832HS, copper foil 5 μm, made by Mitsubishi Gas Chemical Company, Inc.) having a thickness of 0.1 mm, (KMC L518A 0.105 x 1.8 Union Tool Co.), the number of revolutions: 330,000 rpm, the feed rate: 8 mu m / rev. , 20 holes were drilled at 3,000 hits per drill bit.

For drilling with a drill bit diameter of 0.08 mmφ, four layers of a copper clad laminate (CCL-HL832HS, copper foil 5 μm, made by Mitsubishi Gas Chemical Company, Inc.) having a thickness of 0.1 mm were laminated and a layer of the water- (KMV J948 0.08 x 1.2 manufactured by Union Tool Co.), the number of revolutions: 330,000 rpm, the feed rate: 6 mu m / rev. , 20 holes were drilled at 3,000 hits per drill bit.

(Evaluation 1) Hole position accuracy

The hole position of 3,000 hits on the back surface of the lowest plate of the laminated copper-clad laminate and the displacement of the designated coordinates were measured using a hole analyzer (product number HA-1AM, manufactured by Hitachi Via Mechanics, Ltd.) The average value and standard deviation (?) Were calculated for each drill bit, and the average value + 3? Was calculated. Then, the average value of the "average value + 3σ" of 20 times of drilling was calculated.

Table 3 shows the evaluation results of hole position accuracy. Figs. 4, 5, and 6 are graphs showing the relationship between the average grain size of grains, the standard deviation of crystal grain size, the surface roughness Sm, and the hole position accuracy.

(Evaluation 2) The winding amount of the resin

For each of 20 drill bits after 3,000 hits drilling, the amount of winding of the resin with respect to the drill bit diameter was observed using a microscope (product number VHK-100, manufactured by Keyence Corporation) with a magnification of 25 times. The results of the observation are evaluated based on the following criteria, and the evaluation results are shown in Table 3.

?: The maximum diameter of the resin wound is less than 1.5 times the diameter of the drill bit.

?: The maximum diameter at which the resin is wound is 1.5 times or more the diameter of the drill bit.

X: The resin wound around the drill bit drops onto the surface of the entry sheet during drilling.

(Evaluation 3) Number of breakage of drill bit

By using 20 drill bits, drilling was performed, and the number of breakage of the drill bit was counted. Table 3 shows the results of drill bit breakage.

Based on the contents of the evaluations 1 to 3, comprehensive judgment was made according to the following criteria.

A: average grain size of crystal grains: 40 占 퐉 or less / standard deviation of grain size average grain size: 17 占 퐉 or less / surface roughness (Sm): 7 占 퐉 or less, hole position accuracy is 23 占 퐉 or less, no drill bit is broken,

O: Average grain size of crystal grains not more than 70 占 퐉 / standard deviation of average grain size of grain not more than 25 占 퐉 / surface roughness (Sm) Not more than 25 占 퐉 at hole position accuracy, no breakage of drill bit,

DELTA: average grain size of grain / standard deviation of grain size / surface roughness (Sm) does not satisfy the claim requirement, hole position accuracy is 25 占 퐉 or less, drill bit is not broken,

X: Average grain size of crystal grains / standard deviation of average grain size / surface roughness (Sm) does not satisfy the claim requirement, hole position accuracy exceeds 25 占 퐉, drill bit is not broken,

××: average grain size of grain / standard deviation of average grain size / surface roughness (Sm) does not satisfy the claim requirement, and drill bit breakage or resin winding

As can be seen from Table 3, the average grain size of the grain, the standard deviation of the average grain size of the grain, and the surface roughness (Sm) were not all small for Comparative Examples 26, 27 and 29, .

The results of Table 3, Fig. 4, Fig. 5 and Fig. 6 show that the water-soluble resin compositions in the samples of Examples 1 to 20 are superior to the comparative examples 1 to 36 in the average particle size of the crystal grains, And the surface roughness (Sm) of the water-soluble resin composition layer and the hole positional accuracy are clear. It is also understood that the water-soluble resin compositions in the samples of Examples 1 to 20 have better results than those of Comparative Examples 1 to 36 even when the resin is wound and the drill bit is broken.

When the average particle diameter and the standard deviation of the grain size of the water-soluble resin composition are small, the hole position accuracy tends to be excellent. When the surface roughness Sm of the entry sheet is small, the winding of the resin is reduced It can be seen that there is a trend.

Table 4 is an excerpt from Example 20 and Comparative Example 21 in which drilling with a drill bit diameter of 0.08 mm was performed in Table 2 and Table 3. From the results in Table 4, , It shows that excellent results are obtained with respect to the average particle diameter of the crystal grains and the standard deviation thereof, the surface roughness (Sm), the hole position accuracy and the reduction of the resin by the quenching effect when the layer made of the water-soluble resin composition is produced Able to know.

Table 5 is an excerpt from Examples 5 and 6 and Comparative Example 22 in which boron drilling with a drill bit diameter of 0.105 mm was carried out in Table 2 and Table 3. From the results of Table 5, Excellent results are obtained with respect to the average particle diameter of the crystal grains and the standard deviation thereof, the surface roughness (Sm), the hole position accuracy and the spinning of the resin by the quenching effect when the layer of the water-soluble resin composition is produced .

[Industrial applicability]

According to the present invention, it is possible to provide a perforated entry sheet which is excellent in hole position accuracy, less resin to be wound around the drill bit, and less damages of the drill bit, as compared with the conventional perforated entry sheet. In addition, it is possible to drill holes with a high accuracy in a very small diameter area, which has been the area of laser drilling so far, and to reduce the number of drill bit breaks by reducing the amount of resin wound on the drill bit. , Industrial value is very high.

Claims (6)

A perforated entry sheet formed of a crystalline water-soluble resin composition and having a thickness of 0.02 to 0.3 mm formed on at least one surface of a metal support foil,
The grain size of the water-soluble resin composition is in the range of 5 to 70 占 퐉, the standard deviation thereof is 25 占 퐉 or less,
The surface roughness (Sm) of the drill bit entry face of the layer made of the water-soluble resin composition is 8 탆 or less,
The layer made of the water-soluble resin composition may be prepared by coating a solution containing the water-soluble resin composition directly on the metal support foil, or after applying a solution containing the water-soluble resin composition and drying, At a cooling rate of 1.5 占 폚 / sec or more at a temperature of 25 占 폚 to 40 占 폚 within 60 seconds from a temperature of 160 占 폚.
The method according to claim 1,
The grain size of the water-soluble resin composition is in the range of 5 to 40 mu m and the standard deviation thereof is not more than 17 mu m,
Wherein the layer made of the water-soluble resin composition has a surface roughness (Sm) of 7 mu m or less on the entrance surface of the drill bit.
The method according to claim 1,
The water-soluble resin composition comprises a water-soluble resin (A) and a hydrophobic substance (B1), a substance (B2) having a melting point higher than that of the water-soluble resin (A) (B3). &Lt; / RTI &gt;
The method according to claim 1,
Wherein the solution containing the water-soluble resin composition further contains water and a solvent having a lower boiling point than water.
The method according to claim 1,
Wherein the metal support foil has a thickness in the range of 0.05 to 0.5 mm.
The method according to claim 1,
Wherein the punched entry sheet is used for processing a copper-clad laminate.

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