KR20080055627A - Sheets for drilling - Google Patents

Abstract

A sheet for drilling is provided to be used for a cover plate providing a high-quality product when a printed circuit board is manufactured. A sheet for drilling is coated with an organic material layer, a metal layer, and an anti-slip layer. The organic layer provides a lubricant function. The metal layer is formed in adjacent to the organic material layer to endow the lubricant function. The anti-slip layer is formed at a remaining surface of the metal layer. The anti-slip layer has a composition identical to that of the organic material layer. The anti-slip layer includes polymer or co-polymer obtained by at least one monomers selected from ethylene, ethylene vinyl acetate, ethyl acrylate, andethyl meta acrylate. The anti-slip layer has a colored layer.

Description

Sheets for drilling

The present invention relates to a sheet for punching processing, and more particularly, to a sheet suitable for a cover plate or the like for efficiently obtaining a high quality product in punching processing, which is one of manufacturing processes of a printed circuit board.

The printed circuit board serves to electrically connect the electronic components to each other by mounting (mounting) the electronic components, which is very important as an internal component of an electric product.

In manufacturing such a printed circuit board, a blank board is placed in a stack of several layers on a backup board, an entry board is placed on the upper surface of the topmost blank board, a through hole is drilled in the entry board from the top, and drilled in this state. Small holes are formed in the blank substrate for a printed circuit board by simultaneously forming small holes in the entire blank substrate.

Commonly used as an entry sheet is a pure aluminum sheet without a lubricating layer, such as an A1000-based aluminum sheet, which mainly prevents breakage and burr formation when puncturing holes in a blank substrate for a printed circuit board. It has been used to improve the position and position.

In recent years, since the electronic components are mounted on the printed circuit board with high density, the circuit line width and spacing are narrowed, the drilling processing equipment is also speeded up, and the number of boards is also increased. Therefore, small holes having a diameter of 0.35 mm or less must be formed.

However, using pure aluminum plate without a lubrication layer as the entry board caused problems of position accuracy and breakage of the drill bit after the pore. In the case of using the aluminum sheet, since the drill blade is frequently broken or the drill bit itself is broken, it is impossible to increase the number of stacks of blank substrates for drilling to provide a printed circuit board, resulting in poor efficiency. . In addition, since the drill blade forms a skid on the substrate surface, there is a problem that the small holes are not formed at the correct position. Another problem is that the inner circumferential wall surface that partitions the pores becomes rough and encounters problems in the subsequent plating process.

Therefore, in order to solve such a problem, to prevent breakage and breakage of the drill blade, to prevent roughening of the inner circumferential surface partitioning the pores, and to improve the position of the pores to be formed on the blank substrate. A resin-coated metal sheet having a lubricating layer on at least one surface of the metal sheet by adhering the sheet has been proposed.

For example, Korean Patent Publication No. 2002-0018984 discloses a printed circuit board perforated lubricant sheet having an organic material layer having a thickness of 2 to 300 μm on one surface of a metal foil having a thickness of 5 μm to 500 μm. Examples thereof include a mixture in which the organic material layer contains a polyether ester, a solid water-soluble lubricant, and polyethylene glycol; Or a sheet for lubricating printed circuit boards, which is a mixture containing polyetherester, solid water soluble lubricant, and liquid water soluble lubricant.

In addition, Korean Patent Publication No. 2003-0036041 discloses an entry sheet in which a metal foil is bonded to one surface of an entry sheet including a water-soluble resin and a water-insoluble lubricant.

As another technique, Korean Patent Laid-Open Publication No. 2005-0056149 discloses a resin-coated metal plate in which at least one surface of the metal plate is coated with a thermoplastic resin, wherein the thermoplastic resin is substantially water-insoluble and measured in accordance with JIS K7121. The melting peak temperature of the resin is in the range of 60 ° C to 120 ° C and the melt viscosity in the state of melting the thermoplastic resin at 150 ° C is in the range of 1 × 10 ³ to 1 × 10 ⁴ poise at a shear rate condition of 200 mm / sec. It is disclosed that it is preferable that the durometer D hardness of the thermoplastic resin measured in accordance with JIS K7125 is in the range of 5 × 10 ² to 5 × 10 ³ poise at 3000 mm / sec.

Sheets according to the above-described technique all have a structure in which an organic material layer, ie, a lubrication layer, is provided to impart lubricity to at least one surface of the metal layer.

Therefore, in the punching process of a printed circuit board, the surface which contact | connects on the copper foil which is a blank substrate is a metal layer, and the copper foil when the metal layer of a punching sheet contact | connects on the copper foil which is a blank board | substrate. There is a lack of adhesion between the sheet and the gap is formed in the air layer, and also can not absorb the rotational vibration of the drill machine due to this may cause a fine sliding phenomenon. This can cause slippage in the drilling of the drill, whereby the lubricant material drawn from the lubrication layer is mixed with the pored substrate chip, which is difficult to discharge during suction (chip suction), so that it is caught on the substrate contact surface of the drilling sheet. The phenomenon occurs, causing a malfunction of the drill machine. This results in the inability to carry out the designed hole making.

Accordingly, the inventors of the present invention, while seeking to obtain high quality efficiency by increasing the adhesion between the sheet for drilling and the substrate in punching a printed circuit board, the other surface of the metal layer, which is not adjacent to the lubricating layer, is tested in the slip test. As a result of having tanθ of more than a predetermined value, the adhesiveness between the sheet for drilling and the substrate was improved, and it was found that slippage between layers could be prevented, thereby completing the present invention.

Accordingly, an object of the present invention is to provide a sheet for punching which can prevent the sliding phenomenon between the sheet for punching and the substrate in the punching of a printed circuit board.

It is also an object of the present invention to provide a sheet for drilling, which can improve the straightness of a drill in drilling a printed circuit board.

Another object of the present invention is to provide a perforated sheet which can maintain the wear resistance of the drill.

Another object of the present invention is to provide a sheet for drilling, which can reduce the smear of the inner wall of a hole in a substrate.

In the embodiment of the present invention; A metal layer formed adjacent to the organic material layer to impart a lubricating function; And it is formed on the other side of the metal layer, provides a sheet for drilling processing comprising a non-slip layer made of the same or different resin composition and the organic material layer to impart a lubrication function.

According to an embodiment of the present invention, the anti-slip layer in the sheet for drilling may be a film layer including a polymer or copolymer obtained from at least one monomer selected from ethylene, ethylene vinyl acetate, ethyl acrylic acid and ethyl methacrylic acid.

According to the embodiment of the present invention, any one of the organic material layer or the anti-slip layer imparting a lubricating function in the sheet for drilling may further include a colored layer on a surface not adjacent to the other layer.

According to the embodiment of the present invention, in the sheet for drilling, the anti-slip layer may have a tanθ of 20 ° or more at the time of slipping with respect to the copper foil when the tilt test is performed using the slip method using a slip tester. have.

According to the present invention, in a sheet for drilling processing comprising an organic material layer and a metal layer imparting a lubricating function, the other surface of the metal layer, which is not adjacent to the organic material layer, has a tanθ with respect to the copper foil surface according to the slip test. As a result of having a predetermined value or more, the adhesion to the substrate is improved, so that no air layer is formed between the substrate and the sheet, so that the straightness of the drill can be improved in drilling, and the vibration of the drill can be reduced. It is possible to maintain the wear resistance of the drill to extend the drill replacement time, and to prevent the risk of malfunction by preventing the introduction of chips discharged between the substrate and the metal layer.

The present invention will be described in more detail as follows.

Sheet for drilling according to the present invention is one surface of the metal layer is provided with an organic material layer, that is, a lubrication layer to give a lubrication function, the other surface of the metal layer is carried out the slope test using the slip method using a slip tester When it does, tan (theta) at the time of sliding with respect to copper foil is 20 degrees or more.

When the other surface of the metal layer, which is not in contact with the lubricating layer, slips with respect to the copper foil when the tilt test according to the slip test is performed at 20 ° or more, the substrate constituting the copper foil or the like is formed. Excellent friction on the surface can improve the position accuracy during drilling. In other words, the predetermined process capability index (Process Capability Index), in particular, the bias coefficient (Cpk) can be satisfied. Specifically, when the other surface of the metal layer, which is not in contact with the lubricating layer, slips with respect to the copper foil when the other surface of the metal layer performs the tilt test according to the slip test, the finally obtained sheet for punching is used. Process Capability Index (Cpk), especially the bias coefficient (Cpk) measured in the range of 2.1 to 2.4, shows excellent position accuracy.

This tanθ value means that the frictional force is improved compared to the intrinsic frictional force on the metal layer, that is, the copper foil of ordinary aluminum metal, and if the other side of the metal layer, which is not in contact with the lubricating layer, is slippery test When tanθ is smaller than 20 ° with respect to the copper foil, it is not possible to prevent slippage to the substrate such as copper foil of the sheet for drilling.

In order to achieve the technical idea of the present invention, in a sheet for drilling processing including a lubricating layer on a metal layer, a method in which a tan θ according to a slip test satisfies the above range is not particularly limited. As an example of the method for this, a separate resin layer is provided on the other surface of the metal layer which is not in contact with the lubrication layer, or a method of surface processing of the surface of the metal layer itself which is not in contact with the lubrication layer.

When a separate resin layer is provided on the other side of the metal layer, which is not in contact with the lubricating layer, if the tan θ value in the above range can be realized, the composition constituting the resin layer is not particularly limited, and may have a kind of adhesiveness. It is preferable to adjust to the resin composition, which may be the same or different resin layer (lubricated layer in the present invention).

In general, the organic material layer, ie, the lubricating layer, which imparts a lubricating function in the sheet for drilling, may include a water-soluble or water-insoluble polymer and a water-soluble or water-insoluble lubricant.

As a specific example, when water-soluble, the organic material layer may be a mixture including polyether ester, a water-soluble lubricant in a solid phase, and polyethylene glycol having a number average molecular weight of 200 to 600, and may also be a polyether ester, a water-soluble lubricant in a solid phase, and a water-soluble liquid in a liquid phase. It may be a mixture comprising a lubricant.

Preferably, the organic material layer is water-insoluble, and in the case of the water-soluble resin, the adhesion between the resin and the metal layer is poor and the difference in water absorption between the metal may be large, thereby causing warping of the metal plate itself. Therefore, it is preferable that the resin portion used as the matrix is a water-insoluble or 'substantially insoluble' organic material layer which may have some water solubility.

The thickness of the lubricating layer is preferably 20 to 300 μm, but if the thickness is too thin, it is insufficient as a layer that serves as a lubricant during the drilling process and discharges the cutting residue. When the thickness is too thick, the precision of the drilling process is increased. This may worsen or cause damage to the drill.

If the non-slip layer is the same as the lubrication layer composition in the sheet for drilling according to the present invention, it is preferable that the non-aqueous composition is the same as the non-aqueous composition which is a preferable lubrication layer composition.

Such an anti-slip layer not only serves to improve the adhesion between the sheet and the substrate, but also serves as a buffer layer to reduce vibration of the drill and ultimately improve the straightness during drilling. Improving the straightness during drilling can reduce the phenomenon that the chip is buried in the substrate during drilling, that is, smear, thereby improving the quality of the drilled substrate. It also acts as a buffer for drilling to reduce wear on the drill.

The non-slip layer is preferably 50 µm or less in terms of hole workability.

The resin layer may be a film layer comprising a polymer or copolymer obtained from at least one monomer selected from ethylene, ethylenevinylacetate, ethylacrylic acid and ethylmethacrylic acid, preferably obtained from an ethylacrylic acid or ethylmethacrylic acid monomer. It may be a film layer comprising a polymer or a copolymer.

In manufacturing the sheet for drilling according to the present invention, the metal layer, the lubricating layer and the anti-slip layer may be bonded by any one method such as a dry laminate, a wet laminate, and a high temperature laminate method, and may be bonded using a known adhesive. . For example, acrylic adhesives, urethanes, esters, and the like for dry laminates are manufactured and sold as adhesives for high temperature laminates, such as ethylene-vinylacetate copolymer resins, olefins, and rubbers, respectively. .

In addition, when the sheet for drilling processing according to the present invention has a structure in which a resin layer is formed on both sides of the metal layer, if the composition of the lubricating layer and the anti-slip layer is different, distinguishing the upper and lower surfaces of the sheet in preparation for drilling In addition, the color layer may be further included on the back surface of any one of the lubricating layer and the anti-slip layer so as to make it easier to distinguish the bar.

In addition, in the present invention, the antistatic performance may be added to the resin layer to prevent adhesion of fine dust or malfunction of drill processing equipment due to static electricity.

On the other hand, according to the present invention as another method that can realize the tan θ value of the back surface of the metal layer, there is a method of physically or chemically surface-treated the surface of the metal layer, which is not in contact with the lubrication layer without adding a separate resin layer.

In this case, the physical treatment may include patterning or embossing treatment, but is not limited thereto. In addition, the chemical treatment may include, but is not limited to, surface treatment using an acid treatment. When the surface of the metal layer, which is not in contact with the lubricating layer, is treated by physical or chemical methods, the surface roughness of the treated surface is preferably 0.3 μm or more, and when the surface roughness is smaller than 0.3 μm, the lubrication is performed. When the other surface of the metal layer, which is not in contact with the layer, slips with respect to the copper foil when the tilt test according to the slip test is performed, the tan θ cannot be obtained in the above range.

Here, the surface roughness will be understood to mean the surface roughness value Ra measured using a surface roughness measuring instrument (manufactured by Kosaka SE-30C).

Usually, the metal layer constituting the sheet for drilling is preferably aluminum, most preferably pure aluminum having a purity of 99.0%. The thickness of such a metal layer is 5-500 micrometers, Preferably it is 30-300 micrometers, Most preferably, it is 50-200 micrometers.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the Examples.

Preparation Example 1 Preparation of Non-Slip Layer

Note) A 30 μm thick film was extruded at 170 ° C. using a blown extruder using Hanwha LLDPE grade 3120 and Samsung Total EVA 120A.

Preparation Example 2 Preparation of Non-Slip Layer

A 30 μm thick film was extruded at 150 ° C. through a blown extruder using Dow Chemical AFFINITY Grade PL 1840.

Preparation Example 3 Anti-slip through the surface treatment of Al foil

Aluminum foil with a surface roughness of 0.30 μm or more was prepared by improving the roughness by surface treatment by embossing a work roll when Al rolling on one or both surfaces of an aluminum plate having a purity of 99% or more with a thickness of 130 μm.

Example 1

Thickness 30 obtained from the said Preparation Example 1 was made by using the film of 35 micrometers in thickness obtained by using the ethylene metaacrylic acid copolymer resin (DuPont, NUCREL, grade: 0910) as a lubricating layer on both surfaces of the pure aluminum plate of thickness 130micrometer. A micrometer film was laminated and laminated using a laminate adhesive to form a lubricating layer and an anti-slip layer on both sides of the metal layer, respectively, to prepare a sheet for drilling.

Example 2

A metal plate for drilling was manufactured in the same manner as in Example 1, except that the anti-slip layer was formed by laminating the film obtained in Preparation Example 2 using an adhesive.

Example 3

An aluminum foil was manufactured in the same manner as in Preparation Example 3, and a lubrication layer produced by the method of Example 1 was laminated to prepare a metal plate for drilling.

Example 4

In the same manner as in Example 2, a metal plate for drilling was produced. However, the lubricating layer composition was changed to a mixture of ethylene-vinylacetate copolymer resin and ethylene-acrylic acid copolymer resin.

Example 5

A metal plate for drilling was manufactured in the same manner as in Example 1, except that the non-slip layer was formed of a film layer having the same composition as the lubricating layer.

Example 6

A metal plate for drilling was manufactured in the same manner as in Example 2, except that the anti-slip layer was formed of a film layer having the same composition as the lubricating layer.

Comparative Example 1

A metal plate for drilling was manufactured in the same manner as in Example 1, except that the lubricating layer was provided without the slip layer.

Comparative Example 2

A metal plate for drilling was manufactured in the same manner as in Example 4, except that the lubricating layer was provided without the slip layer.

Slip method using a slip tester (Daesung Test Corp., model name YX-219) for comparative experiments of the frictional force with copper foil on the sheet for punching work obtained according to Examples 1 to 6 and Comparative Examples 1 to 2 above. By measuring the tanθ at the time of sliding with respect to the copper foil (기울) by the slope test using the results are shown in Table 1 below.

division Coefficient of friction with the copper foil of the anti-slip layer (tanθ, °) Example One 25 2 30 3 27 4 28 5 27 6 27 Comparative example One 18 2 18

Experimental Example

Drilling was performed on each sheet for punching work obtained from Examples 1 to 6 and Comparative Examples 1 and 2 to evaluate the accuracy of hole position, inner wall roughness, drill breakability, and smear in the hole.

Drilling method is a sheet of non-slip layer (13) in the case of Examples 1 to 6 of the sheet, and the metal layer (1) in the case of Comparative Examples 1 to 3 is a 0.4mm thick double-sided copper foil printed circuit board (FR-4) Product, copper foil 18㎛) to be adjacent to each other, at this time, the printed circuit board 7 overlapping, and further placed a backup board made of bakelite plate 1.5mm thick beneath the printed circuit The substrate was punched out.

Drilling was performed under the following conditions.

Drill bit: diameter 0.25mm

RPM: 125,000rpm

Feed speed: 2.5m / min

Distance between adjacent machining hole centers: 0.5 mm

Number of drill bits: 5000 hits

(1) The determination of the hole position accuracy was carried out on the lowermost substrate (the seventh sheet) after seventy printed circuit boards were stacked and 5000 hits (punched). That is, in the lowermost substrate, an error interval from the center of the hole was measured for the 5000 holes that were heated, and the maximum value thereof was calculated. (DELTA) and the thing of 100 micrometers or more was made into 100 micrometers.

(2) Determination of inner wall roughness is performed on the fifth substrate from above.

Measure the inner wall roughness on the right and left of each drilled hole wall surface of the hole of the 4000th heat and the front and rear two holes, and the average value is less than 5.0 µm, the one less than 7.0 µm, the one less than 10 µm, and the Δ, 10 µm or more. It was.

(3) Smear phenomenon was observed in the holes created through the drill processing test. When the friction heat diffusion was insufficient, the smear increased in the drill bit temperature, softened and melted the resin part of the chip, and the inner layer of the inner wall of the through hole. It refers to the phenomenon of re-adhesion to the copper foil cross section. After cleaning, observe the cross-section of 20 through holes under a microscope, 10 points when no smear is found, 5 points if fine or smear is seen, and smear The case where it was found was made into 0 points.

The measurement results of (1) to (3) are shown in Table 2 below.

Precision of hole position Interior roughness Smear generation of holes Example One ○ ○ 10 2 ◎ ◎ 5 3 ◎ ◎ 5 4 ○ ○ 10 5 ◎ ◎ 10 6 ◎ ◎ 10 Comparative Example One Δ Δ 10 2 × × 0

From the results in Table 2 above, when the anti-slip layer is further provided according to the present invention, the precision of the holes is improved and the roughness of the inner wall is also improved. However, when the surface adjacent to the substrate is a metal layer, it can be seen that the adhesion to the substrate is poor, and thus the precision of the hole is inferior and the hole surface roughness is poor.

Claims (4)

An organic material layer providing a lubricating function; A metal layer formed adjacent to the organic material layer providing a lubricating function; And Formed on the other side of the metal layer, the sheet for drilling processing comprising a non-slip layer made of the same or different resin composition and the organic material layer to impart a lubrication function. The sheet for drilling according to claim 1, wherein the anti-slip layer is a film layer composed of a polymer or a copolymer obtained from at least one monomer selected from ethylene, ethylene vinyl acetate, ethyl acrylic acid and ethyl methacrylic acid. The sheet for drilling according to claim 1, wherein any one of the organic material layer or the anti-slip layer to impart a lubricating function further comprises a colored layer on one surface not adjacent to the other layer. The sheet for drilling according to claim 1, wherein the anti-slip layer has a tanθ of 20 ° or more at the time of slipping with respect to the copper foil obtained by the tilt test using a slip method using a slip tester.