JPH0528783Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to the base material of printed wiring boards used in various OA equipment including computer system equipment, communication equipment, etc. The object of the present invention is to prevent damage to the base material, eliminate defective wiring, and obtain a base material for a printed wiring board with a good yield.

[Conventional technology]

Generally, this type of printed wiring board base material is
1.5 on the surface of the base 11 as shown in FIG.
Ultra-thin copper foil 12 of about micron to 3.0 micron,
12 is attached, and is designed to be cut so that one or more printed wiring boards can be removed from the single base material depending on the use and purpose.

Since the base material in this case is usually cut into a rectangular shape, its four corners 40 are squared at approximately right angles. When transporting, a large number of sheets are stacked, and during the manufacturing process, processed sheets are stacked and worked continuously.

[Problem that the invention attempts to solve]

However, conventionally known base materials for printed wiring boards,
Since the four corners 40 of the rectangular shape are angular as described above, there is a possibility that the corners 40 of the base material may accidentally hit or strongly contact the surface of another base material and damage it during transportation or the manufacturing process. It often happens. For this reason, the ultra-thin copper foil 12 stretched over the base 11 is left with dent marks and becomes even thinner than other parts of the copper foil. It becomes thinner than other parts, and it melts more easily during etching than other parts, and when it comes to printed wiring circuit configurations, the electrical resistance increases, and disconnections occur in the circuit, reducing the reliability of the circuit configuration. There were flaws that impaired the quality of the product.

[Means to try to solve problems]

Therefore, in order to solve the above-mentioned conventional problems and achieve the purpose of the invention, the present invention is a substrate for a printed wiring board that has a thickness of about 0.4 mm to 3.0 mm on both the front and back sides of a substantially rectangular substrate. The peripheral edge of a copper-clad board, which is formed by covering an ultra-thin copper foil of about micron to 3.0 micron, is formed into a substantially semicircular convex arc surface over the entire thickness of the board, eliminating edge angles. The four corners of the convex arc surface are formed into circular arcs forming approximately one-fourth of the circumference, and the convex arc surface is continuous with the peripheral edge and has no edge angle.

[Effect]

The operations or steps based on the above means are as follows.

First, a copper-clad substrate is cut into a rectangle of a size according to the intended use and purpose, and the four sides of the rectangle are cut and the edges are polished to eliminate edge angles and form a substantially semicircular convex arc surface. Next, the four corners are formed into circular arcs of approximately one-fourth of the circumference, and the edges of the circular arc portions are polished to eliminate edge angles and form convex arc surfaces similar to the four sides of the rectangle.

Next, to explain the outline of the manufacturing process of a printed wiring board using the copper-clad board, first, through-holes are drilled, then copper plating is performed, buffing is performed, and photoresist is applied and pasted. Exposure, perform phenomena. Next, etching and resist removal are performed, and then ink coverlay printing is performed.
Then, surface treatment such as solder plating is performed, and finally the external shape and
One process is completed after drilling and other processing.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a copper-clad substrate made of a rectangular base 11 made of glass epoxy or other hard synthetic resin material, Bakelite, paper epoxy or other appropriate material, and copper foil 12 affixed to the front and back surfaces of the base. The thickness can be from 0.4 mm to 3.0 mm depending on the purpose and use, and the copper foil is set to an extremely thin thickness in the range of 1.5 microns to 3.0 microns.

2 is a substantially semicircular convex arc surface formed along the four sides of the rectangular substrate 1 without the edge angle 20 over the entire board thickness, and 3 is a substantially semicircular convex arc surface formed along the four sides of the rectangular substrate 1 by approximately a quarter of the circumference. It is an arc section cut off at a ratio of 1,
The edge angle 30 of the edge of the circular arc portion is eliminated, and a convex arc surface 4 having the same shape as the four sides of the rectangle is formed over the entire thickness of the plate.

[Effect of idea]

Since the present invention has the above configuration, the four sides of the rectangular copper-clad board have reduced edge angles, and the four corners of the rectangle are formed into arcs of approximately one-quarter of the circumference, and the edge angles are eliminated. Even if the corner accidentally comes into contact with the surface of another board during transportation or processing during the manufacturing process, the sharp corner will not damage the ultra-thin copper foil of the other board. Therefore, when processing printed wiring when there are dents, the dents may be made thinner by buffing, and during the etching process, they may melt faster than other parts or may melt unnecessarily. It is extremely practical as a base material for this type of printed wiring board, since there is no risk of an increase in electrical resistance, and accidents such as circuit breakage can be prevented.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a substrate for a printed wiring board according to the present invention, Fig. 2 is a cross-sectional view taken along line 2-2 in Fig. 1, and Fig. 3 is a cross-sectional view taken along line 3-3 in Fig. 1. 4 is a perspective view of a conventional substrate for a printed wiring board, and FIG. 5 is a sectional view taken along line 5--5 in FIG. 4. It is. DESCRIPTION OF SYMBOLS 1... Copper-clad board, 2... Convex arc surfaces on the four sides of the rectangular board, 3... Arc parts at the four corners of the rectangular board, 4... Convex arc surfaces of the arc parts, 20... Edge angles of the four edges of the rectangle, 30 …
...The edge angle of the edge of the arc.

Claims (1)

[Scope of utility model registration request] An ultra-thin copper foil of approximately 1.5 microns to 3.0 microns is applied to both the front and back sides of a substantially rectangular substrate with a thickness of approximately 0.4 mm to 3.0 mm. The convexity is formed into a substantially semicircular convex arc surface with no edge angle, and the four corners of the copper-clad board are formed into circular arcs forming approximately a quarter of the circumference, and the convexity is continuous with the peripheral edge and has no edge angle. A base material for printed wiring boards characterized by being formed into an arcuate surface.