JPH04246884A - Plating method of circuit board - Google Patents

Abstract

PURPOSE:To enable a large number of wiring patterns to be connected at a single joint so as to enhance a circuit board in density by a method wherein the wiring patterns provided to both the front and rear of the circuit board are connected through through-holes. CONSTITUTION:Through-holes 14 are provided to a copper plated board 11 of glass epoxy resin or phenolic resin, the disused part of copper is removed through etching, and then wiring patterns 13 are formed on the front and rear of the board 11, resist is made to cover all the surface of the board excluding connection parts such as lands 12 or the like, and then gold plating is executed. All the wiring patterns 13 provided onto both the sides of the circuit board 11 are electrically connected together through the through-holes 14, and the lands located on both the sides of the board 11 are plated with gold. After a gold plating process is finished, a hole 15 larger than the through-hole 14 in diameter is punched with a press or bored with a drill so as to prevent a short circuit from occurring between the wiring patterns to shut off unneeded electrical conduction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method of plating circuit boards for electronic equipment, and more particularly to a method of plating high-density double-sided circuit boards.

0002

BACKGROUND OF THE INVENTION Recently, as electronic devices become more sophisticated, the lands of circuit boards are often plated with gold to improve conductivity and prevent rust. Furthermore, when bare chip ICs and the like are wire-bonded with gold wires, the lands that receive the bare chips are plated with gold to improve bonding with the gold wires.

When performing gold plating, all wiring patterns must be electrically conductive, and as shown in FIG.
Wiring patterns 3, 3... of each land 2, 2... provided in
are connected at the connecting part 4. After each land 2, 2, . . . is plated with gold, a hole 5 having a larger diameter than the connecting portion 4 is bored by a press or drill, as shown by the chain line, to cut off mutual conduction.

0004

[Problems to be Solved by the Invention] In the conventional circuit board plating method, as mentioned above, the wiring patterns 3, 3... are connected at the connection part 4 to achieve continuity during plating. On the board, the wiring patterns 3, 3, . . . become finer, and the number of wiring patterns 3, 3, . . . connected at one connection portion 4 increases. However, there is a limit to the number of connections of the wiring patterns 3, 3, . Therefore, the drilling work for holes 5, 5, etc. to be performed after gold plating increases,
As the number of work steps increases, unnecessary holes 5, 5 are formed on the circuit board 1.
...will remain in large numbers.

[0005] Therefore, a technical problem has arisen that must be solved in order to reduce the number of connecting parts for plating in a high-density double-sided circuit board and to reduce the work of drilling holes after plating. The invention aims to solve this problem.

[0006]

[Means for Solving the Problems] The present invention has been proposed to achieve the above object, and involves connecting wiring patterns provided on both sides of a circuit board through through holes, and plating both sides of the circuit board. The present invention provides a method for plating a circuit board, which is characterized in that, after performing the above steps, a large diameter hole is drilled into a predetermined through hole to interrupt conduction of the wiring pattern.

[0007]

[Operation] This invention connects the wiring patterns of the circuit board using through holes. Through-holes provide electrical continuity between the wiring patterns on both sides of the circuit board, so multiple wiring patterns on both sides of the circuit board can be connected with one through-hole.
The number of connection points for plating can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. 1 to 4. FIG. 1 shows the surface of a circuit board 11 of an electronic device, and each land 12, 12... is connected to a wiring pattern 13, 1.
3. It is connected at... Although not shown, a wiring pattern is also provided on the back surface of the circuit board 11 to form a land. Then, the wiring patterns 13, 13 on the surface
... and the wiring pattern on the back surface are electrically connected to each other through a through hole 14. Therefore, the lands 12 on the front and back sides of the circuit board 11
, 12... and the wiring patterns 13, 13... are all electrically conductive.

FIG. 2 shows the procedure for forming the circuit board 11. First, through-holes are formed in a copper-coated board made of glass epoxy resin, phenol resin, etc., and unnecessary parts of the copper are removed by etching. Form wiring patterns on both sides. Next, resist is coated except for connection parts such as lands, and gold plating is performed. Since the wiring patterns provided on both sides of the circuit board are all electrically conductive through the through holes, each land on both sides of the circuit board is plated with gold. After gold plating, in order to prevent short circuits between the wiring patterns, a hole with a larger diameter than the through hole is punched or drilled to interrupt unnecessary conduction.

As shown in FIG. 3 and FIG.
Because it connects..., many wiring patterns can be connected with one through hole. Therefore, the number of connection points for gold plating on the high-density double-sided circuit board is reduced, and the work of drilling large diameter holes 15 into predetermined through holes 14 after gold plating can be reduced.

[0011] This invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that the invention extends to such modifications.

0012

Effects of the Invention As described in detail in the above-mentioned embodiment, this invention connects the wiring patterns on both the front and back sides of the circuit board to be plated using through holes, so that a large number of wiring patterns can be connected at one connection point. can. Therefore, it is possible to increase the density of the circuit board, reduce the number of connecting parts for plating, and shorten the hole-drilling process after plating.

[Brief explanation of the drawing]

FIG. 1 is a plan view of essential parts of a circuit board.

FIG. 2 is a block diagram showing the steps of a plating method.

FIG. 3 is a plan view of essential parts of a through hole.

FIG. 4 is a sectional view taken along line AA in FIG. 3;

FIG. 5 is a plan view of main parts of a conventional circuit board.

[Explanation of symbols]

11 Circuit board 12 Land 13 Wiring pattern 14 Through hole 15 Hole

Claims (1)

[Claims] 1. Wiring patterns provided on both sides of a circuit board are electrically connected through through holes, plating is applied to both sides of the circuit board, and then large diameter holes are drilled into predetermined through holes to form wiring patterns. A method for plating a circuit board, characterized by cutting off conduction.