JP2000025000A - Entry sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an entry sheet and a small diameter hole boring work method being easy in manufacture and causing no problem as industrial waste by restraining a slip of a drill in the sheet surface, improving accuracy of a hole position, and reducing breaking of the drill. SOLUTION: An entry sheet for a printed wiring board has an oxide film having a thickness of 0.1 to 3 μm on the surface of an aluminum or aluminum alloy sheet having a thickness of 0.09 to 0.30 mm, and has the surface roughness of Ry (a maximum height): 2 to 15 μm and Sm (an average interval of recess/ projection): 10 to 120 μm measured by a method of JIS B 0601 (1994). The printed wiring board is laminated, and the entry sheet is superposed on it so that the oxide film becomes outside to perform boring work from the oxide film surface by a drill.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an entry sheet used for drilling a small-diameter hole in a product such as a printed circuit board, which requires high precision, by suppressing a drill from slipping on a surface. Entry for small-diameter drilling of high-quality, high-efficiency printed wiring boards, etc. by improving position accuracy, reducing breakage of drills, preventing damage to printed circuit boards such as copper foil, and improving product yield. The present invention relates to a sheet and a method for making a hole using the sheet.

[0002]

2. Description of the Related Art Electronic technology includes computers such as telephones, TVs and personal computers, lighting equipment and other control devices in various manufacturing industries, as well as electric and communication fields, but also automobiles, home appliances, office equipment, cameras, toys, etc. It is applied to an extremely wide range, and is required to have higher functions and higher precision. With this, finer patterns, higher densities, and multilayer boards of printed wiring boards are rapidly progressing. As a result, the wiring width and the wiring interval of the printed wiring board are narrowed, and in particular, in a through-hole type printed wiring board, the number of holes is reduced and the number of holes is increased, and the position of the holes is also required to be more accurate. It is becoming. 2. Description of the Related Art Conventionally, in the drilling of a multilayer board, small-diameter processing of 0.3 to 0.4 mmφ has been frequently performed. In the future, it is considered that the demand for the positional accuracy will be increased from the level of the hole diameter of 100 μm or less to the current hole diameter of 50 μm or less.

In order to perform such small-diameter drilling,
Specifically, if the entry sheet is provided on the printed wiring board and drilling is performed, the bite of the drill is improved, the accuracy of the positions of the holes provided in the printed wiring board is improved, and burrs and burrs do not occur. It has been known that such holes can be made, and some proposals have been made for an entry sheet used for this. For example, a method of drilling a printed wiring board using an entry sheet in which both surfaces of a substrate made of wood pulp and glass fiber are sandwiched between aluminum foils or the like (Japanese Patent Application Laid-Open No. 61-61921).
), A method of drilling a printed wiring board using an entry sheet in which both sides of an aluminum foil are sandwiched between papers (Japanese Patent Application Laid-Open No. 62-214000), and a method of forming an adhesive sheet on one side of a metal foil. Entry sheets have been proposed, such as a method in which the adhesive phase side is installed facing a printed wiring board and drilling is performed (Japanese Patent Laid-Open No. 63-11207).

However, in the invention described in Japanese Patent Publication No. Sho 60-61921, the surface material of the entry sheet is 30
Since a hard material such as 03-H19 is used, the side slip of the drill is likely to occur, and the hole position accuracy is apt to decrease. In addition, when an adhesive is used for manufacturing an entry sheet, the number of layers becomes five, and an increase in cost is inevitable. Japanese Patent Application Laid-Open No. 62-2140
In the invention of No. 00, the paper does not have heat resistance, and there is a great risk that paper powder is generated and causes a defect in a subsequent process such as plating. Furthermore, the invention of Japanese Patent Application Laid-Open No. 63-11207 has a problem because it is inevitable that chips are attached to the adhesive layer during drilling. In order to improve the accuracy of the hole position, the use of an entry sheet whose surface is coated with a polymer resin such as polyethylene glycol for improving lubricity is also proposed and used, but the cost is extremely high and the entry sheet is used. There are many points to be improved, for example, such that the workability is extremely poor due to the curvature, and there is a problem in disposing of used entry sheets as industrial waste.

As described above, although the conventional method still has a problem in drilling a small-diameter hole, the pattern of a printed wiring board is further reduced in size, the diameter of a hole to be drilled is reduced, and
As the number of holes increases, drills have to be rotated at higher speeds, the drill thickness has become thinner, the occurrence of shaking due to rotation has increased, and the demand for hole position accuracy and the allowable height of burrs has been strict. Despite the fact that the same entry sheet is used as before, if the hole position accuracy becomes insufficient, it is attempted to improve the hole position accuracy, or if you try to suppress the burr generation below the conventional There is a problem that the breakage of the drill increases and the productivity decreases.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to an entry sheet for drilling holes in a printed wiring board or the like in which the slip on the surface of the entry sheet of the drill is suppressed, the accuracy of the hole position is improved, and the breakage of the drill is reduced. An object of the present invention is to develop an aluminum sheet to be used, which is easy to manufacture and has no problem as an industrial waste of used entry sheets, and to develop a small-diameter drilling method using the same.

[0007]

According to the present invention, there is provided (1) a sheet of aluminum or aluminum alloy having a thickness of 0.09 to 0.30 mm (hereinafter collectively referred to as "aluminum sheet"). 1-3 μm
Having an oxide film having a surface roughness of JIS B 060
1 (1994), Ry (maximum height): 2 to 15 μm (standard length: 0.80 mm, evaluation length: 4.00 mm), Sm (average interval of unevenness): 10
120 μm (standard length: 0.80 mm, evaluation length: 4.
00mm) entry sheet for printed wiring boards,
(2) The surface of an aluminum sheet having a thickness of 0.09 to 0.30 mm is mechanically, chemically or electrochemically roughened, and then anodized to a thickness of 0.1 to 3 μm.
The surface roughness Ry measured by the method of JIS B 0601 (1994) is 2 to 15 μm (reference length: 0.
80 mm, evaluation length: 4.00 mm), Sm: 10-1
20 μm (standard length: 0.80 mm, evaluation length: 4.0
(3) a method for manufacturing an entry sheet for a printed wiring board, wherein an oxide film is formed by anodizing treatment having a thickness of 0.09 to 0.2 mm. An aluminum sheet having a thickness of 30 mm has an oxide film having a thickness of 0.1 to 3 μm on its surface, and its surface roughness is measured by the method of JIS B 0601 (1994), Ry: 2 to 15 μm (standard length: 0. 80
mm, evaluation length: 4.00 mm), Sm: 10 to 120
μm (standard length: 0.80 mm, evaluation length: 4.00 m
The above-described method for forming a hole in a printed wiring board is characterized in that a printed wiring board entry sheet is overlapped so that the oxide film is on the outside and the hole is formed by drilling from the oxide film surface. The goal was achieved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The aluminum sheet used for the entry sheet in the present invention is, in principle, pure aluminum or the alloy component is not particularly limited, and is a sheet having a thickness of 0.09 to 0.30 mm. Use The aluminum sheet material is not particularly limited, but is usually 1050, 1100, 3003.
And the like. 0.0 as sheet thickness
If the thickness is less than 9mm, it is easy to deform and the handling is troublesome.
The biting of the drill is not stable, and the position accuracy of the hole position is deteriorated. On the other hand, if the thickness exceeds 0.3 mm, there is no particular advantage and the cost is merely increased.

An oxide film having a thickness of 0.1 to 3 μm is provided on the surface of this aluminum sheet, and the surface roughness of the oxide film surface is measured according to the method of JIS B 0601 (1994). ): 2 to 15 μm (reference length: 0.80 mm, evaluation length: 4.00 mm), Sm
(Average interval of unevenness): 10 to 120 μm (reference length:
0.80 mm, evaluation length: 4.00 mm). When drilling a hole using such an aluminum sheet using an entry sheet, it is possible to prevent the lateral escape of the drill, the hole position accuracy can be made ± 25 μm or less, and the breakage of the drill should be 3000 hits or more. It has no coating of polymer such as polyethylene glycol on the surface and has excellent workability without curving, and it is easy to recycle as a recycled material without problems of industrial waste regulations, and it is an entry with high industrial value It is a sheet.

[0010] In order to ensure the roughness of the aluminum sheet oxide film surface as Ry: 2 to 15 µm and Sm: 10 to 120 µm, the aluminum sheet must be previously mechanically, chemically or electrochemically roughened. It is advantageous to provide an ultrathin oxide film having an oxide film thickness of 0.1 to 3 μm since the surface is formed and then anodized to provide an ultrathin oxide film having a thickness of 0.1 to 3 μm. This oxide film is
It is chemically very stable, and since it is a relatively hard film, it can stably protect a roughened surface for a long time. It is also useful for preventing fingerprints, oils, moisture, etc. from adhering to the surface during transportation and handling, and preventing performance degradation due to corrosion. When the thickness of the oxide film is less than 0.1 μm, these effects cannot be expected. When the thickness exceeds 3 μm,
The effect is saturated, and conversely, the surface roughness cannot be maintained and the performance as an entry sheet cannot be sufficiently exhibited. In particular, since the oxide film is relatively hard, the breakage of the drill increases, the wear of the drill blade becomes severe, the life of the drill is shortened, and the sharpness of the drill is reduced. It is not preferable because many problems occur.

The roughness of the oxide film surface of the entry sheet is measured according to the method of JIS B 0601 (1994), Ry (maximum height): 2 to 15 μm (reference length:
0.80 mm, evaluation length: 4.00 mm), preferably Ry: 3 to 8 μm, Sm (average interval of unevenness): 10 to 1
20 μm (standard length: 0.80 mm, evaluation length: 4.0
0 mm), preferably Sm: 20 to 70 μm. Within this range, the lateral escape of the drill can be effectively prevented, and the positional accuracy is improved. If it is rougher than this range, the lateral clearance becomes large depending on the ground contact position of the drill. On the other hand, if it is too fine, the effect of the surface roughness of the entry sheet cannot be obtained, so that the occurrence of lateral escape also increases.

[0012]

Examples (Examples 1 to 7 and Comparative Examples 1 to 6) A 1050 aluminum alloy having a thickness shown in Table 1 was used as an aluminum sheet, and the drilling conditions were as follows. Drill diameter used: 0.25 mmφ Worked printed wiring board: FR-4 (double-sided board) 0.4 mm thick x 3 layers Backup board: Bakelite (thickness 1.6 mm) Number of revolutions: 80000 rpm. Feeding speed: 1.5 mm / min. Number of hits: 3000 hits [Measurement method] After electrochemically roughening the surface of an aluminum sheet, an oxide film having the thickness shown in Table 1 was formed by anodic oxidation using a general sulfuric acid bath, and JIS B 0601 (1)
994), the surface roughness of the entry sheet is determined as a reference length: 0.80 mm, and an evaluation length is 4.00 m.
m, Ry (maximum height) μm, and reference length: 0.
At 80 mm and an evaluation length of 4.00 mm, Sm (average interval of unevenness) μm was measured. For the measurement of the performance, the maximum deviation of the hole position at the exit of the third printed wiring board from the theoretical value is displayed, and the measured values are summarized in increments of 5 μm. Table 1 shows the results.

[0013]

[Table 1]

[0014]

With the recent increase in the performance of printed wiring boards, demands for smaller diameter holes, higher precision in hole positions, and higher productivity are increasing. In response to this, we have taken measures such as reducing the thickness of the drill, rotating the drill at high speed, and maintaining a high feed rate. As the thickness becomes thinner, breakage of the drill increases, resulting in higher cost and lower productivity, and the lowering of the sharpness of the drill makes it difficult to form a clean cut surface on the inner wall of the hole. In order to solve such problems, there is a proposal to apply PEG or the like to an aluminum sheet. However, there is a problem that the treatment is difficult due to the curving of the sheet and the regulation of industrial waste of the coating agent, and the recyclability is impaired. It is derived.
The present invention forms an oxide film on the surface of the entry sheet and prevents the drill from escaping laterally by suppressing the surface roughness of the surface within a certain range. The number of breakage was significantly reduced even when the size became smaller, and an entry sheet that succeeded in maintaining high productivity even when using a low-cost sheet was successfully developed. The entry sheet is easy to use without curving of the sheet, and has excellent performance with excellent recyclability without being subject to regulations on industrial waste.

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryosuke Shimao 224 Kaiyamacho, Sakai-shi, Osaka Showa Aluminum Co., Ltd. F-term (reference) 3C036 AA01 3C060 AA11 BA05 BG01

Claims (3)

[Claims] An aluminum or aluminum alloy sheet having a thickness of 0.09 to 0.30 mm (hereinafter collectively referred to as an "aluminum sheet") having a thickness of 0.19 mm.
酸化 3 μm oxide film with surface roughness of JIS B
Ry (maximum height): 2 to 15 μm (standard length: 0.80 mm, evaluation length: 4.00 mm), Sm (average interval of unevenness): 1 as measured by the method of 0601 (1994).
0 to 120 μm (standard length: 0.80 mm, evaluation length:
4.00 mm) entry sheet for printed wiring boards. 2. The surface of an aluminum sheet having a thickness of 0.09 to 0.30 mm is mechanically, chemically or electrochemically roughened, and then anodized to a thickness of 0.1 to 0.30 mm.
3 μm, surface roughness Ry measured by the method of JIS B 0601 (1994): 2 to 15 μm (standard length: 0.80 mm, evaluation length: 4.00 mm), Sm:
A method for producing an entry sheet for a printed wiring board, comprising forming an oxide film by anodic oxidation treatment having a thickness of 10 to 120 µm (reference length: 0.80 mm, evaluation length: 4.00 mm). 3. A printed wiring board is laminated, and an aluminum sheet having a thickness of 0.09 to 0.30 mm is provided thereon with an oxide film having a thickness of 0.1 to 3 μm on a surface thereof. Ry: 2 to 15 μm (reference length: 0.80 mm, evaluation length: 4.00 mm), Sm: 10 to 120 μm (reference length: 0.80 mm, evaluation length) measured by the method of B0601 (1994). (4.00 mm). A method for forming a hole in a printed wiring board, comprising stacking printed wiring board entry sheets having an oxide film on the outside and drilling a hole from the oxide film surface with a drill.