RU2526652C1 - Drilling mask - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: ply containing polymer composition is made at, at least, one surface of bearing metallic foil of said mask. Said polymer comprises solid lubricant composed by at least one of the following substances zinc molybdate and molybdenum trioxide. Polymer composition ply depth makes 0.02-0.3 mm.

EFFECT: accurate positioning of bores, safety of drill tip.

11 cl, 4 dwg, 1 tbl

Description

FIELD OF TECHNOLOGY

The present invention relates to a stencil (sheet with a hole pattern) for drilling holes, which is used when drilling holes in a multilayer (layered) material plated with copper, or in a multilayer printed circuit board.

BACKGROUND OF THE INVENTION

A common method for drilling holes in a copper-clad multilayer material or in a multilayer printed circuit board that is used for the manufacture of printed circuit boards is a method in which over a single sheet or a bundle of a plurality of sheets of copper-clad multilayer material or a multilayer printed circuit board boards placed a sheet of simple metal foil, for example of aluminum foil, or a sheet obtained by applying a layer of a polymer composition on the surface of a metal foil ( e in the proposed description, this sheet is called a "stencil for drilling holes"), used as a reinforcing plate, and then drill holes.

Recently, the requirements for multilayer materials clad with copper or multilayer printed circuit boards used as materials for printed circuit boards include increasing the density of components, increasing productivity, reducing costs and increasing reliability; Obviously, to meet these requirements, high quality drilling is required in combination with increased hole accuracy and similar parameters. For example, to meet the requirements in Patent Document 1, a drilling method was proposed using a stencil containing a water-soluble polymer such as polyethylene glycol. In addition, a stencil for drilling was proposed in Patent Document 2, which includes a lubricant and a layer of a water-soluble polymer deposited on a metal foil. Additionally, Patent Document 3 proposes a stencil for drilling holes, including a layer of a water-soluble polymer deposited on an aluminum foil on which there is a thin film of a thermosetting polymer. In addition, to extend the life of the drill tip, Patent Documents 4 and 5 suggest the use of an auxiliary material containing compound nanopowders.

Nevertheless, compared with the development of the semiconductor industry, the development of technologies related to printed circuit boards is slow, which widens the gap between these industries. Thus, the need to achieve a high density of components and increase the reliability of printed circuit boards is steadily increasing. For example, the minimum diameter of the drill tip in mass production is reduced from 0.2 mm to 0.18 mm and 0.15 mm, and finally to 0.105 mm. In addition, competition with laser drilling led to attempts to drill holes with a diameter of 0.08 mm, 0.075 mm and 0.05 mm, which were only partially crowned with success. Additionally, increased competition as a result of globalization and the emergence of new developing countries on the market leads to the need to increase productivity and reduce costs. Thus, there is an urgent need to create a new stencil for drilling holes that meets the above requirements.

Background Documents

Patent documents

Patent Document 1: JP-A-H4-92494

Patent Document 2: JP-A-H5-169400

Patent Document 3: JP-A-2003-136485

Patent Document 4: JP-U-3134128

Patent Document 5: JP-A-2007-281404

SUMMARY OF THE INVENTION

The tasks solved by the invention

In view of the above circumstances, the object of the present invention is to provide a stencil for drilling holes, providing a higher accuracy of the location of the holes compared to a conventional stencil for drilling holes. The creation of such a stencil for drilling holes is extremely desirable in order to increase the density of the components, increase reliability and productivity, and reduce costs.

Ways to solve the problems of the invention

As a result of various studies, the authors of the present invention were able to solve the above problem by introducing into the polymer composition a stencil for drilling holes of at least one of the following substances: zinc molybdate and molybdenum trioxide used as solid lubricant (B), and optimization of their added quantity. It was found that this facilitates the insertion of the tip of the drill into the material and improves the centering of the tip of the drill, which increases the accuracy of the location of the holes. In addition, it was found that the action of zinc molybdate and molybdenum trioxide as solid lubricants can increase the lubricity of the material and facilitate chip removal, that is, prevent chip sticking and loss, which reduces the likelihood of a breakdown of the drill tip when the drill tip hits large pieces of chips .

According to the invention, alignment (centering) refers to the property of moving directly in the direction of drilling during drilling. For example, at the point where the tip of the drill is in contact with the layer of the polymer composition of the stencil for drilling holes, the cutting edge of the tip of the rotating tip of the drill, sliding, cuts through the surface of the layer of the polymer composition. Since the cutting edge of the tip of the drill tip easily slides to the side, a simple increase in lubricity can impair centering and reduce the accuracy of the holes.

The basis of the present invention was based on the discovered patterns, and the essence of the present invention is as follows.

(1) A stencil for drilling holes in which a layer comprising a polymer composition is formed on at least one surface of a carrier metal foil, the polymer composition as a solid lubricant (B) comprising at least one of the following: zinc molybdate and trioxide molybdenum, and the layer thickness of the polymer composition is from 0.02 to 0.3 mm

(2) A stencil for drilling holes according to the above paragraph (1), in which the polymer composition comprises a water-soluble polymer (A).

(3) A stencil for drilling holes according to the above paragraph (1), in which the total content of solid lubricant (B) in the polymer composition is from 1 mass. parts up to 40 mass. parts in terms of 100 mass. parts of the polymer content in the composition.

(4) A stencil for drilling holes according to the above item (1), in which the average particle size of zinc molybdate is from 1 to 7 microns.

(5) A stencil for drilling holes according to the above item (1), in which the average particle size of the molybdenum trioxide is from 3 to 35 microns.

(6) A stencil for drilling holes according to paragraph (1) above, used for drilling with a drill tip whose diameter is not more than 0.2 mm.

(7) A stencil for drilling holes according to the above (1), wherein the thickness of the carrier metal foil is from 0.05 to 0.5 mm.

(8) A stencil for drilling holes according to the above item (1), in which a polymer membrane is applied as a primer to the supporting metal foil.

(9) A stencil for drilling holes according to the above item (8), in which the primer layer includes a solid lubricant (B).

(10) A stencil for drilling holes according to the above paragraph (9), in which the added amount of solid lubricant (B) in the primer layer is from 1 mass. parts to 20 mass. parts in terms of 100 mass. parts of the primer composition.

(11) Stencil for drilling holes according to the above paragraph (1), used in the processing of multilayer materials, clad with copper, or multilayer printed circuit boards.

The beneficial effect of the invention

The use of a stencil for drilling holes according to the present invention reduces the likelihood of breakage of the tip of the drill during drilling due to the high accuracy of the location of the holes during drilling and high lubricity of the layer of the polymer composition. As a result, it becomes possible to further increase the density of components and drill with higher quality and increased productivity. Alternatively, it is possible to increase the number of stencils in a bundle that can be drilled at a time, which makes a certain contribution to increasing productivity and reducing costs.

BRIEF DESCRIPTION OF GRAPHIC MATERIALS

A more detailed description of the present invention is given below, accompanied by graphic materials, in which:

1 shows a scanning electron microscope micrograph (× 10,000 magnification) of zinc molybdate (supplied by Nippon Inorganic Color & Chemical Co., Ltd, particle size from 0.4 μm to 13 μm, average particle size of 3 μm, multilayer structure );

2 shows a scanning electron microscope micrograph (× 10,000 magnification) of molybdenum trioxide (supplied by Nippon Inorganic Color & Chemical Co., Ltd, particle size 0.7 to 55 μm, average particle size 16 μm, prismatic structure) ;

figure 3 presents a comparison chart of the accuracy of the location of the holes obtained in the Examples and Comparative Examples during processing under conditions of 1 drilling; and

figure 4 presents a comparison chart of the accuracy of the location of the holes obtained in the Examples and Comparative Examples when processing in conditions 2 drilling.

INTELLIGENCE. SUMMARY OF THE INVENTION

The drill hole stencil of the present invention is a hole drill stencil comprising a layer comprising a polymer composition (hereinafter referred to as a "polymer composition layer") deposited on at least one surface of a metal carrier foil. The stencil for drilling holes according to the present invention is characterized in that the polymer composition comprises a solid lubricant (B).

According to the present invention, solid lubricant (B) is any solid used in the form of a thin film or powder to protect the surface from damage during relative movement, as well as to reduce friction or abrasion, the melting temperature of which is at least 300 ° C. thermally stable and remaining solid and not melting in air at a temperature of 200 ° C, that is, at a temperature exceeding the temperature of use of materials according to the present invention niyu.

In addition, the added amount of at least one of the following substances: zinc molybdate and molybdenum trioxide, used as solid lubricant (B), has been optimized. This facilitates the insertion of the drill tip into the material, improves the centering of the drill tip, which increases the accuracy of the hole location, and, in addition, improves the lubricity of the material and facilitates chip removal, that is, to prevent sticking and chip falling out, which reduces the likelihood of breakage of the drill tip when the drill tip hits large pieces of chips.

In addition, the polymer composition according to the present invention is preferably a composition comprising a water-soluble polymer (A). According to the invention, the water-soluble polymer (A) is a water-soluble polymer, a water-soluble lubricant other than solid lubricant (B).

Of course, the polymer composition may include a known water-insoluble thermoplastic polymer, a water-insoluble lubricant other than solid lubricant (B), and, for example, a nucleating agent, a coloring agent, a heat stabilizing agent, and other similar additives.

The polymer content of the polymer composition includes the content of a water-soluble polymer (A), a water-insoluble lubricant other than a solid lubricant (B), and a water-insoluble thermoplastic polymer. In addition to its primary purpose, the polymer contained in the polymer composition also serves as a carrier transferring the solid lubricant (B) to the drill tip and printed circuit board material.

The total content of solid lubricant (B) is from 1 mass. parts up to 40 mass. parts, preferably from 1 mass. parts up to 30 mass. parts, more preferably from 5 mass. parts to 20 mass. parts and most preferably from 10 mass. parts to 20 mass. parts in terms of 100 mass. parts of the polymer content in the polymer composition. If the content of solid lubricant (B) is less than 1 mass. parts, then a beneficial effect is not observed. If the content of solid lubricant (B) is more than 40 mass. parts, it is economically disadvantageous, and the solid lubricant (B) easily forms aggregates. This leads to production problems, and therefore, the accuracy of the location of the holes may be deteriorated.

According to the present invention, the solid lubricant (B) comprises at least one of the following substances: zinc molybdate (MoO ₄ Zn, melting point 900 ° C) and molybdenum trioxide (MoO ₃ , melting point 795 ° C). Although it is traditionally believed that solid molybdenum trioxide is not lubricating, it has been found that it is suitable for use as a solid lubricant (B) introduced into a stencil for drilling holes. Solid lubricant (B) may include at least one or more of these substances.

Compared to solid lubricants such as molybdenum disulphide and mica, solid lubricant (B) has a remarkable functional effect, even if it is added in small quantities, which are preferred. A noticeable functional effect, even in small amounts, is also preferable from the point of view of selecting the parameters of the polymer to be included in the polymer composition.

In general, the mechanism of action of solid lubricant (B) is believed to be as follows. Firstly, the content in the lubricant layer of solids having a suitable hardness improves contact between the tip of the drill tip and the solid lubricant (B) and the insertion of the drill into this material. This ensures high accuracy of the location of the holes in the first stage. Secondly, when solid lubricant (B) is introduced into the lubricant layer, solid lubricant (B) contacts the surface and grooves of the drill tip and the wall of the hole obtained in the printed circuit board material. Since solid lubricant (B) has a volume and hardness inherent in a solid material, it is always present between a copper plated multilayer material or a multilayer printed circuit board and a drill tip, improving lubricity and preventing abrasive wear on the drill tip. Thirdly, since the solid lubricant (B) is fixed in the groove of the drill tip, this solid lubricant gives the groove lubricity and facilitates chip removal, preventing it from sticking together.

It should be noted that the abrasive wear of the drill tip is of two types. The first includes initial abrasive wear. In particular, at the beginning of drilling, the tip of the drill breaks in the part that receives the impact. The remarkable lubricity characteristic of the solid lubricant (B) described above can reduce the initial abrasive wear of the drill tip compared to drilling in the absence of a solid lubricant (B). The second type includes permanent abrasive wear. In particular, the tip of the drill wears out as the number of drilled holes increases. However, the lubricity characteristic of solid lubricant (B) also reduces permanent abrasive wear compared to drilling in the absence of solid lubricant (B). Thus, although in the case of drilling in the absence of a solid lubricant (B) as the number of drilled holes increases, the accuracy of the location of the holes deteriorates, a decrease in accuracy can be prevented by using a solid lubricant (B).

The solid lubricant (B) may be introduced into the polymer membrane (which may be referred to as the primer layer) applied to the carrier metal foil. Since the primer layer is an interface in contact with aluminum foil, the densest packaging in the primer layer improves the accuracy of the location of the holes. The total content of solid lubricant (B) is from 1 mass. parts to 20 mass. parts, more preferably from 5 mass. parts to 10 mass. parts in terms of 100 mass. parts of the primer composition. If the added amount of solid lubricant (B) is less than 1 mass. parts, then a beneficial effect is not observed. If the added amount of solid lubricant (B) is more than 20 mass. parts, it is economically disadvantageous, and adhesion between a thin primer layer and a supporting metal foil may also deteriorate. As the polymer used to form the primer layer into which the solid lubricant (B) is introduced, both a thermosetting polymer and a thermoplastic polymer can be used. To increase the accuracy of the location of the holes, it is more preferable that the polymer of the primer layer is a thermosetting polymer.

Preferably, the optimal type, particle size, and added amount of solid lubricant (B) are selected depending on the technical characteristics of the copper-clad multilayer material or the multilayer printed circuit board.

The reason why, for example, zinc molybdate has the properties of a solid lubricant (B) is as follows. Zinc molybdate is a solid substance having a layered structure, the particle size of which is from 0.2 μm to 15 μm, the average particle size is from 1 to 7 μm, and, in addition, it has a suitable volume and adequate hardness. The average particle size is preferably from 2 to 6 microns. More preferably, the average particle size is from 3 to 5 microns. The listed properties facilitate the insertion of a small-diameter drill tip into the material in cases where hole accuracy is an important parameter. In addition, since zinc molybdate has a layered structure including thin layers, it easily enters the groove of the drill tip when the latter rotates, which facilitates chip discharge.

The reason molybdenum trioxide has the described functional effect is as follows. Molybdenum trioxide is obtained by oxidation of molybdenum disulfide; Molybdenum trioxide is a solid having a prismatic structure, the particle size of which is from 0.7 μm to 55 μm, the average particle size is from 3 to 35 μm, and the molybdenum trioxide has a suitable volume and adequate hardness. The average particle size is preferably from 5 to 20 microns. More preferably, the average particle size is from 10 to 18 microns. The listed properties facilitate the insertion of a small-diameter drill tip into the material in cases where hole accuracy is an important parameter. In addition, the average particle size of the molybdenum trioxide is less than the depth of the groove of the drill tip, and they easily fall into the groove of the drill tip when the latter rotates, which facilitates chip discharge.

As for the particle sizes of the solid lubricant (B), the average particle size is more important than the maximum particle size. This is because the particle size of the solid lubricant having a high content in the polymer composition affects the accuracy of the location of the holes and the lubricity of the stencil for drilling holes. Thus, in order to improve the technical characteristics of the stencil for drilling holes, it is important to adjust the average particle size of the solid lubricant (B). Thus, a situation in which the proportion of particles of maximum size in the particle size distribution in the solid lubricant (B) is so large that it leads to an increase in the average particle size is undesirable, since in this case the lubricity of the solid may be lower than expected. A method for determining the particle size of a solid lubricant (B) involves dispersing a sample in a solution containing a 0.2% solution of hexametaphosphoric acid and a few drops of 10% triton, and then using a laser diffraction device to determine the distribution of particle size (model number: SALD -2100, supplied by Shimadzu Corporation) determine the maximum length of each projection of particles of solid lubricant (B). Then, based on the calculations, a particle size distribution curve is constructed. The range of the curve is taken as the particle size range of the solid lubricant (B), and the particle size corresponding to the maximum of the curve is taken as the average particle size.

In particular, if the solid lubricant (B) is zinc molybdate and molybdenum trioxide, then such a material does not loosen, although it cannot be said that it is completely insoluble in water. This property is useful in industrial applications, because it allows you to not strictly control the moisture content, as in the case of friable solid lubricants. According to the invention, to determine the absence of loosening, an aqueous solution containing 10 mass. parts of solid lubricant is placed in 90 mass. parts of water, mix thoroughly, leave for 1 hour, and then measure the height of the sediment solid lubricant; if the relative height of the sediment is at least 90%, then it is believed that the material forms a dispersion or loosens; if the relative height of the sediment is from at least 50% to less than 90%, then it is believed that the material is loosened; and if the relative height of the sediment is less than 50%, then it is believed that the material is not loosened. In the case of one of the experiments with zinc molybdate, the height to the liquid surface was 66 mm, the height to the upper surface of the deposited part of zinc molybdate was 21 mm, the relative height of the precipitate was 32%, and there was a clear separation between the two layers. Similarly, in the case of one of the experiments with molybdenum trioxide, the height to the liquid surface was 35 mm, the height to the upper surface of the deposited part of molybdenum was 5 mm, the relative height of the precipitate was 14%, and the solution was from the upper surface of the deposited part of molybdenum trioxide to the liquid surface muddy.

Upon receipt of a solution of a water-soluble polymer (A), the described properties lead to the following advantages. The material is easily dispersible and poorly aggregated. If, after drilling, zinc molybdate or molybdenum trioxide remains in the hole, they can easily be removed by washing. However, during the preparation of the water-soluble polymer solution (A), a concentration gradient of the solid lubricant (B) is created, and therefore, the solution needs to be mixed.

If the Mohs hardness of the solid lubricant (B) exceeds 5, then it has an abrasive effect, which is undesirable. The optimum added amount of solid lubricant (B) may vary depending on the required characteristics of the printed circuit board being drilled. Compared to printed circuit board material that does not contain inorganic filler, the abrasive wear of the drill tip when drilling material for printed circuit board that includes inorganic filler is relatively high, that is, in this case it may be preferable to add a large amount of solid lubricant ( AT).

The choice of the type of water-soluble polymer (A) is not particularly limited, but preferably the water-soluble polymer is one or two or more substances selected from the group consisting of, for example, polyethylene oxide, polypropylene oxide, sodium polyacrylate, polyacrylamide, polyvinylpyrrolidone, carboxymethyl cellulose, polytetramethylene polyethylene and polyalkylene glycol. The polyalkylene glycol polyester is a condensation product obtained by the reaction of a polyalkylene glycol with a dibasic acid. Examples of the polyalkylene glycol are preferably selected from glycols, non-limiting examples of which include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and their copolymers, and partial esters of polycarboxylic acids, for example phthalic acid, isophthalic acid, terephthalic acid, sebacellic acid, and sebacellic acid, can be selected. acid anhydrides and the like. A water soluble lubricant other than solid lubricant (B) includes polyethylene glycol, polypropylene glycol; polyoxyethylene monoesters, examples of which include polyoxyethylene oleyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether and the like; polyoxyethylene monostearate; polyoxyethylene sorbitol monostearate; polyglycerol monostearates, examples of which include hexaglycerol monostearate, decaghexaglycerol monostearate and the like; a polyoxyethylene propylene copolymer and the like, and, in accordance with the purposes of the particular application, preferably one or two or more substances are suitably used.

The choice of a water-insoluble thermoplastic polymer is not particularly limited, and known substances can be used. Such materials include, for example, an amide-based elastomer, butadiene-based elastomer, ester-based elastomer, olefin-based elastomer, urethane-based elastomer, styrene-based elastomer, polybutene, low density polyethylene, chlorinated polyethylene, metallocene-based polyolefin polymer copolymer of ethylene, acrylic ester and maleic anhydride, ethylene glycidyl methacrylate copolymer, ethylene vinyl acetate copolymer resin, modified ethylene vinyl acetate copolymer resin , Copolymer of ethylene and methacrylic acid resin, ionomer resin, ethylene copolymer resin and a methacrylic ester compound and the like.

The choice of a water-insoluble lubricant other than solid lubricant (B) is not particularly limited, and well-known substances can be used. Examples of such substances include amide-based compounds, for example ethylene bis-stearamide, oleic acid amide, stearic acid amide, methylene-bis-stearamide and the like, fatty acid-based compounds, examples of which include lauric acid, stearic acid, palmitic acid, oleic acid and the like, fatty acid ester compounds, examples of which include butyl stearate, butyl oleate, glycol laurate and the like, aliphatic hydrocarbon compounds s, examples of which include liquid paraffins, polyethylene waxes and the like, higher aliphatic alcohols, examples of which include oleic alcohol and the like, and the like.

The thickness of the layer of the polymer composition may be different, and its choice depends on the diameter of the drill tip used when drilling, the structure of the processed multilayer material clad with copper, or a multilayer printed circuit board and similar factors, but usually this thickness is from 0.02 to 0.3 mm, a preferred value is from 0.02 to 0.2 mm. If the layer thickness of the polymer composition is less than 0.02 mm, then a sufficient lubricating effect cannot be achieved, as a result of which the load on the drill tip increases and the likelihood of breakage of the drill tip is increased. On the other hand, if the layer thickness of the polymer composition is more than 0.3 mm, the amount of polymer composition wound around the tip of the drill may increase.

A method for producing the polymer composition layer described above may include a method for directly coating and drying the hot melt or applying a solution of the polymer composition to a carrier metal foil, a method for coating and similar methods or a method for preforming a sheet of a polymer composition from a hot melt and securing it to a carrier metal foil and similar methods. In this regard, for laminating and fixing the layer of the polymer composition on the carrier metal foil, it is preferable to have a preformed polymer membrane (primer layer) on the carrier metal foil. This method is described in more detail below.

Additionally, if a method for directly coating and drying a solution of the polymer composition on a carrier metal foil or a similar method is used for coating, the solution used is preferably a solution containing water and a solvent whose boiling point is lower than the boiling point of water. The choice of a solvent whose boiling point is lower than the boiling point of water is not particularly limited, and examples thereof may include alcohols, for example ethanol, methanol and isopropyl alcohol; in addition, low boiling solvents such as methyl ethyl ketone and acetone may be used. As other solvents, it is possible to use solvents containing tetrahydrofuran or acetonitrile, which are well compatible with the polymer composition, in the form of partial mixtures in water and alcohols. The mixing ratio of water and solvent, the boiling point of which is lower than the boiling point of water, should be from 90/10 to 50/50, and preferably it is from 80/20 to 50/50, more preferably from 70/30 to 50/50 and most preferably from 60/40 to 50/50. If the mixing ratio of water and solvent, the boiling point of which is lower than the boiling point of water, is less than 10, then the formation of dense spherulites from the water-soluble polymer (A) can be difficult. If the mixing ratio of water and solvent, the boiling point of which is lower than the boiling point of water, is more than 50, then it is possible to reduce the stability of the process in industrial production.

In addition, if a coating method is applied directly and drying a solution of the polymer composition on a carrier metal foil, a hot melt coating method or a similar method, then the temperature of the stencil for drilling holes should be lowered from values of 120 ° C to 160 ° C, to normal temperature in a time of 5 to 30 seconds. If the drying temperature exceeds 160 ° C, it is possible to reduce the stability of the process, which is undesirable in industrial production. Also, if the temperature to which cooling is performed is less than the usual temperature, then condensation may form after completion of the method, which is undesirable.

The choice of carrier metal foil used to make a stencil for drilling holes according to the present invention is not particularly limited, provided that it consists of a metal material having high adhesion to the polymer composition according to the invention, which can withstand the impact of the drill tip. The thickness of the carrier metal foil is usually from 0.05 to 0.5 mm and preferably from 0.05 to 0.3 mm. If the thickness of the supporting metal foil is less than 0.05 mm, then during the drilling process burrs are easily formed in the multilayer material, and if it is more than 0.5 mm, the ejection of the chips formed during the drilling process is difficult. As a metal material for a carrier metal foil, for example, aluminum can be used. To obtain aluminum foil, aluminum grades with a purity of at least 95% are preferred, for example, grades 5052, 3004, 3003, 1N30, 1N99, 1050, 1070, 1085, 8021 and similar grades listed in JIS-H4160. The use of high-purity aluminum metal foil as a material allows one to absorb the impulse of the drill tip, increase the cutting properties of the drill tip and improve the accuracy of hole placement when drilling holes, which is further enhanced by the lubricating effect of the polymer composition exerted on the drill tip. In addition, to increase the adhesion of the polymer composition, it is preferable to use a carrier metal foil, on the surface of which a polymer membrane (primer layer) with a thickness of 0.002 to 0.02 mm is applied in advance. If solid lubricant (B) is introduced into the polymer membrane, then the corresponding thickness of the polymer membrane is selected depending on the particle size of the solid lubricant (B). The choice of polymer used to obtain the polymer membrane is not particularly limited, provided that it has increased adhesion to the polymer composition; either a thermoplastic polymer or a thermosetting polymer can be used for this. For example, a urethane-based polymer, a vinyl acetate-based polymer, a vinyl chloride-based polymer, a polyester-based polymer, an acrylic-based polymer and their copolymers can be used as a thermoplastic polymer. As thermosetting polymers, epoxy-based polymers and cyanate-based polymers can be used.

A drilling stencil according to the present invention is used in drilling material for printed circuit boards, for example, copper plated laminate or a multilayer printed circuit board. In particular, a stencil for drilling holes is placed on top of one sheet or bundle of many sheets of multilayer material, clad with copper, or multilayer printed circuit boards so that the surface of the carrier metal foil is in contact with the material for the printed circuit board, and drilling can be done from the side surface layer of the polymer composition.

The above description is only one example of embodiments of the present invention, which may be modified without departing from the scope of the invention limited by the claims.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Below is a description of the results obtained in the Examples according to the present invention, and their comparison with the results obtained in the Comparative Examples, not included in the scope of the present invention. It should be borne in mind that "polyethylene glycol" can be denoted by the abbreviation "PEG", and "polyethylene oxide" by the abbreviation "PEO".

Example 1

30 mass. parts of polyethylene oxide, the mass-average molecular weight of which was 150,000 (ALTOP MG-150, supplied by Meisei Chemical Works, Ltd.), and 70 mass. parts of polyethylene glycol, the mass-average molecular weight of which was 20,000 (PEG20000 supplied by Sanyo Chemical Industries, Ltd.) was dissolved in a mixture of water / MeOH (methanol) so that the solid polymer content was 30%. The ratio of water to MeOH in solution was 60/40. In addition, a solid lubricant (B), which consisted of 5 masses, was added to the solution of the resulting water-soluble polymer composition. parts of zinc molybdate (which is supplied by Nippon Inporganic Color & Chemical Co., Ltd, particle size from 0.4 μm to 13 μm, average particle size of 3 μm), in terms of 100 mass. parts of a water-soluble polymer composition that is thoroughly dispersed. A solution of the obtained water-soluble polymer composition was applied using a barcode coating device on the aluminum foil, one of the surfaces of which was already coated with an epoxy polymer membrane 0.01 mm thick (used aluminum foil: 1N30, 0.1 mm thick supplied by Mitsubishi Aluminum Co, Ltd.) so that the layer thickness of the water-soluble polymer composition after drying was 0.05 mm, dried in a drying apparatus at 120 ° C. for 5 minutes, and then cooled to normal temperature to obtain stencil for drilling holes.

Examples 2-14

Water-soluble polymer compositions, the parameters of which are presented in Table 1, were obtained in accordance with the method described in Example 1; these compositions were used to make stencils for drilling holes in which the layer thickness of the water-soluble polymer composition after drying was 0.05 mm.

Comparative Examples 1-11

Water-soluble polymer compositions, the parameters of which are presented in Table 1, were obtained in accordance with the method described in Example 1; these compositions were used to make stencils for drilling holes in which the layer thickness of the water-soluble polymer composition after drying was 0.05 mm.

Assessment Methods

For each of the stencils for drilling holes obtained in the Examples and Comparative Examples, the following definitions were made.

(1) hole accuracy

A stencil for drilling holes was placed on top of the stack of multilayer materials clad with copper so that the layer of the polymer composition was the top layer and drilling was performed. Drilling was performed at 6000 strokes with one drill tip and repeated using four drill tips. The discrepancy between the location of the holes on the back surface of the bottom board of the bundle of multilayer materials clad with copper and the given coordinates was measured for holes obtained with the number of strokes from 1 to 1500 and from 1 to 6000 strokes per drill tip using the hole location analyzer (number Models: HA-1AM supplied by Hitachi Via Mechanics, Ltd.); then calculated the average value and standard deviation (σ), as well as the parameter "average value + 3σ". In addition, the average value of the parameter "average value + 3σ" was calculated for the four drill tips; The results obtained are presented in Table 1.

As criteria for the accuracy of the location of the holes, the accuracy of the location of the holes obtained with the number of impacts from 1 to 1500, i.e. in the absence of abrasive wear of the drill tip, or the accuracy of the location of the holes obtained with the number of impacts from 1 to 6000, that is, in the presence of abrasive wear of the tip, was used drill. If the score with the number of strokes from 1 to 1500 and from 1 to 6000 was “◯”, then the overall score was also “◯”.

(2) Method for measuring particle size of solid lubricant (B)

The method for determining the particle sizes of solid lubricant (B) included dispersing a sample in a solution containing a 0.2% solution of hexametaphosphoric acid and a few drops of 10% triton, and then using a laser diffraction device to determine the distribution of particle size (model number: SALD -2100, supplied by Shimadzu Corporation) determined the maximum length of each of the projections of the particles of solid lubricant (B). Then, based on the calculations, a particle size distribution curve was constructed. The range of the curve was taken as the particle size range of the solid lubricant (B), and the particle size corresponding to the maximum of the curve was taken as the average particle size.

Table 1 Water Soluble Polymer (A) Solid lubricant (B) Drilling conditions The accuracy of the location of the holes after the total number of drills (strokes) Overall rating Type of The added amount (mass. Parts) 1,500 strokes 6000 hits Wednesday (microns) Rating Wednesday (microns) Rating Example 1 one 3 5 one 20.7 ◯ 26.9 ◯ ◯ Example 2 one 3 10 one 19,2 ◯ 29.6 ◯ ◯ Example 3 one 3 twenty one 19,4 ◯ 29.5 ◯ ◯ Example 4 one 3 40 one 20.1 ◯ 25.8 ◯ ◯ Example 5 one four 10 one 20.8 ◯ 26.2 ◯ ◯ Example 6 2 3 5 one 19.0 ◯ 25.0 ◯ ◯ Example 7 2 3 10 one 20.3 ◯ 26,4 ◯ ◯ Example 8 2 3 twenty one 20,0 ◯ 26.1 ◯ ◯ Example 9 2 3 40 one 19.1 ◯ 25,4 ◯ ◯ Example 10 2 four 10 one 19.8 ◯ 26.5 ◯ ◯ Example 11 one 3 5 2 18.0 ◯ 30,0 ◯ ◯ Example 12 one 3 10 2 20,0 ◯ 32.9 ◯ ◯ Example 13 one 3 twenty 2 21.6 ◯ 36.8 ◯ ◯ Example 14 one 3 40 2 18.8 ◯ 30.8 ◯ ◯ Comparative Example 1 one 8 0 one 27.9 × 35.5 × × Comparative Example 2 one 3 60 one 24.5 × 34.8 × × Comparative Example 3 one 3 80 one 23.0 × 26.7 ◯ × Comparative Example 4 one 5 5 one 19.8 ◯ 31,4 × × Comparative Example 5 one 5 10 one 19.3 ◯ 31.1 × × Comparative Example 6 one 5 twenty one 22.3 × 35.8 × × Comparative Example 7 one 5 40 one 23.1 × 37.1 × × Comparative Example 8 one 6 10 one 24.4 × 31.3 × × Comparative Example 9 one 7 10 one 22.2 × 33,4 × × Comparative Example 10 2 8 0 one 25,4 × 31.9 × × Comparative Example 11 one 8 0 2 28.3 × 41,4 × × Criteria for evaluation Drilling Conditions: 1 ◯: no more than 21 microns ◯: no more than 30 microns ◯: Both scores at 1,500 and 6,000 hits were ◯ Drilling Conditions: 2 ◯: no more than 26 microns ◯: no more than 40 microns

The composition of the water-soluble polymer (A):

1) 30 mass. parts of polyethylene oxide (ALTOP MG-150, supplied by Meisei Chemical Works, Ltd., Mw = 150,000), 70 mass. parts of polyethylene glycol (PEG20000 supplied by Sanyo Chemical Industries, Ltd., Mw = 20000), a total of 100 mass. parts.

2) 20 mass. parts of a copolymer of simple and complex ester (Paogen PP-15, supplied by Dai-ichi Kogyo Seiyaku Co., Ltd., Mw = 100000), 80 mass. parts of polyethylene glycol (PEG4000S, supplied by Sanyo Chemical Industries, Ltd., Mw = 4000), a total of 100 mass. parts.

Types of solid lubricant (B):

3) Zinc molybdate (supplied by Nippon Inporganic Color & Chemical Co., Ltd, particle size 0.4 μm to 13 μm, average particle size 3 μm, multilayer structure).

4) Molybdenum trioxide (supplied by Nippon Inporganic Color & Chemical Co., Ltd, particle size from 0.7 μm to 55 μm, average particle size of 16 μm, prismatic structure).

5) Molybdenum disulfide (M-5 Powder supplied by Daizo Corporation, particle size 0.5 to 29 μm, average particle size 5 μm, multilayer structure).

6) Loosened mica (ME-100, supplied by Co-op Chemical Co., Ltd., particle size 5 to 7 μm, multilayer structure).

7) Non-disintegrating mica (MK-200, supplied by Co-op Chemical Co., Ltd., particle size 5 to 8 μm, multilayer structure).

8) No solid lubricant (B) was added.

The amount of solid lubricant added (B):

Solid lubricant (B) was introduced in an amount of 0, 5, 10, 20, 40, 60 or 80 mass. parts in terms of 100 mass. parts of the polymer content in the polymer composition.

Drilling conditions:

1) The diameter of the tip of the drill: 0.2 mm (C-CFU020S, supplied by Tungaloy Corporation), the number of revolutions: 200000 rpm, feed speed: 20 μm / rev, lift speed: 25.4 m / min, the processed base material HL832 containing no inorganic filler 0.2 mm, Cu 12 µ, a pack of five stencils.

2) The diameter of the tip of the drill: 0.2 mm (C-CFU020S, supplied by Tungaloy Corporation), the number of revolutions: 200000 rpm, feed speed: 20 μm / rev, lift speed: 25.4 m / min, processed base material HL832HS containing inorganic filler 0.2 mm, Cu 12 µ, a pack of five stencils.

From the results presented in Table 1, it can be seen that, compared with the samples obtained in Comparative Examples 1-11, the samples obtained in Examples 1-14 provide high accuracy of hole location both in the case of abrasive wear of the drill tip and in in the absence of abrasive wear. In particular, the use of zinc molybdate and molybdenum trioxide according to the present invention leads to a significant increase in the accuracy of the hole arrangement in comparison with traditionally used molybdenum disulfide, a disintegrated mica and an unloosened mica.

INDUSTRIAL APPLICATION

According to the present invention, a stencil for drilling holes can be obtained, providing a higher accuracy of the location of the holes and a lower probability of breaking the tip of the drill compared to traditional stencils for drilling holes.

Claims (11)

1. A stencil for drilling holes in which a layer comprising a polymer composition is formed on at least one surface of a carrier metal foil, the polymer composition comprising at least one of the following substances as solid lubricant (B): zinc molybdate and molybdenum trioxide while the thickness of the layer of the polymer composition is from 0.02 to 0.3 mm 2. A stencil for drilling holes according to claim 1, in which the polymer composition includes a water-soluble polymer (A). 3. The stencil for drilling holes according to claim 1, in which the total content of solid lubricant (B) in the polymer composition is from 1 wt. parts up to 40 wt. parts in terms of 100 wt. parts of the polymer content in the composition. 4. The stencil for drilling holes according to claim 1, in which the average particle size of zinc molybdate is from 1 to 7 microns. 5. The stencil for drilling holes according to claim 1, in which the average particle size of the molybdenum trioxide is from 3 to 35 microns. 6. The stencil for drilling holes according to claim 1, which is used for drilling with a drill tip, the diameter of which is not more than 0.2 mm 7. The stencil for drilling holes according to claim 1, in which the thickness of the carrier metal foil is from 0.05 to 0.5 mm 8. The stencil for drilling holes according to claim 1, in which on the supporting metal foil as a primer layer there is a polymer membrane. 9. The stencil for drilling holes of claim 8, in which the primer layer includes a solid lubricant (B). 10. The stencil for drilling holes according to claim 9, in which the added amount of solid lubricant (B) in the primer layer is from 1 wt. parts up to 20 wt. parts in terms of 100 wt. parts of the primer composition. 11. The stencil for drilling holes according to claim 1, which is used in the processing of multilayer materials, clad with copper, or multilayer printed circuit boards.

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