JPH04199759A - Printed board - Google Patents

Abstract

PURPOSE:To enable a lead to be adhered by allowing it to land at a soldering part securely by laminating a circuit pattern and a soldering part and burying them and by making lower a surface of the soldering part which is exposed on the surface as compared with the surface for providing a stage difference. CONSTITUTION:A resist 2 corresponding to a shape of a circuit pattern is formed on a carrier 1 and a circuit pattern 3 is formed. Then, the resist 2 is released and the circuit pattern 3 is buried at a substrate main material 4 by a lamination press means. Then, the carrier 1 is released from the circuit pattern 3, the circuit pattern 3 is transferred to the main material 4, a surface part of the circuit pattern 3 is eliminated by etching, and a recessed part 5 is formed on an upper surface of the circuit pattern 3. A soldering part 6 is formed in lamination and a surface of the soldering part 6 which is exposed on a surface of the main material 4 is lowered as compared with a surface of the main material 4 by a stage difference d, thus enabling a recessed part 5 to remain partially for preventing a lead from being slid from the soldering part and enabling it to land at the soldering part positively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a printed circuit board, and is designed to ensure that the leads of electronic components land on the solder portions of the circuit board.

(Prior art) As a means of mounting electronic components on a printed circuit board, a circuit pattern is formed on the main material of the board by etching, etc.
Furthermore, a solder part is formed on the electrode part of this circuit pattern using a solder leveler or solder plating, and after landing the lead of the electronic component on this solder part, the solder part is heated and melted.
The leads are bonded to the electrode portions of the circuit pattern.

(Problems to be Solved by the Invention) However, since the solder portion is higher than the surface of the board, there is a problem in that the lead easily slips off the solder portion when the lead lands on the solder portion.

Especially in recent years, due to the demand for high density and high integration, lead i'
Since there is a tendency for L to be pinched more and more narrowly, even a slight positional deviation due to slipping of L 1 tends to cause mounting defects.

Therefore, an object of the present invention is to provide a printed circuit board that can prevent the leads from slipping.

(Means for Solving the Problems) The present invention laminates and embeds a circuit pattern and a solder part on the surface of a main board material, and the surface of the solder part exposed on the surface of the main board material is A step is provided at the same level as or lower than the surface.

(Function) According to the above configuration, the leat does not slip off from the solder portion and can reliably land on the solder portion.

(Example 1) Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the manufacturing process of a printed circuit board. Same figure (
In a), 1 is a carrier made of a thin metal plate such as SUS, and a resist 2 corresponding to the shape of the circuit pattern is formed on this carrier 1 (FIG. 2(b)), and then on this carrier 1, A circuit pattern 3 is formed by copper plating means (see (C) in the same figure).

Next, the resist 2 is peeled off (FIG. 2(d)), and the circuit pattern 3 is embedded in the substrate main material 4 by lamination press means (
Figure (e)). The main material 4 is, for example, glass fiber impregnated with epoxy resin, and has some softness.

Next, the carrier I is peeled off from the circuit pattern 3, and the circuit pattern 3 is transferred to the main material 4 (FIG. 4(f)). Next, the surface layer of the circuit pattern 3 is removed by etching to form a recess 5 on the upper surface of the circuit pattern 3 (FIG. 3(g)). This etching may be performed on the entire surface of the circuit pattern 3, or may be performed only on the portions where solder portions will be formed in the next step to become electrode portions.

Next, a solder portion 6 is laminated on the circuit pattern 3 by plating means or the like (FIG. 6(h)).

In this case, the surface of the solder portion 6 exposed on the surface of the main material 4 is made to be lower than the surface of the main material 40 by the step d, so that the recessed portion 5 is partially left.

The printed circuit board 10 is formed through the above steps.

When mounting an electronic component such as a QFP on this printed circuit board 10, flux is applied to the solder portion 6, and the leads L are landed on the solder portion 6 (see Fig. 2).
. As described above, since the solder part 6 is formed in the recess 5, the solder part 6 can be fitted into the recess 5 and positioned, and can securely land on the solder part 6, and then the solder part 6 can be heated and melted. As a result, the leads are bonded to the solder portion 6.

(Example 2) In FIG. 3, after forming the resist 2 on the carrier 1,
A solder portion 6 is formed on the non-resist surface, and then a circuit pattern 3 is laminated on the solder portion 6 (FIGS. 3(a) to (d)).

Next, after peeling off the resist 2, the solder portion 6 and the circuit pattern 3 are embedded in the substrate main material 4 (see (e) and (f) in the same figure).

Next, the carrier 1 is peeled off, and the solder portion 6 and the circuit pattern 3 are transferred to the main material 4 (FIG. 1(g)). Next, the surface layer of the solder portion 60 is removed by etching to form the recess 5, and the step d is removed. ((h) in the same figure. Therefore, also by this method, the lead can be fitted into the recess 5 and positioned.

In the above embodiment, the solder part 6 is lower than the surface of the main board material 4 by providing a step d, but even if the solder part 6 is at the same level as the surface of the main board material 4, the lead L solder part 6
It is also possible to keep them at the same level since this will prevent them from slipping off.

(Effects of the Invention) As explained above, the present invention laminates and embeds a circuit pattern and a solder part on the surface of a main board material, and the surface of the solder part exposed on the surface of the main board material is Since the step is provided at the same level as the surface of the material or lower than the surface, the lead that lands on the solder area will not slip and become misaligned, and the lead will land securely on the solder area. You can stand by.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which Fig. 1 is a manufacturing process diagram of the printed circuit board 1, Fig. 2 is a sectional view of the main part during mounting, and Fig. 3 is a printed circuit board of another embodiment. FIG. 3...Circuit pattern 4...Board main material 6...Solder part 10...Print 1-board

Claims (1)

[Claims] The circuit pattern and the solder part are layered and buried on the surface of the main board material, and the surface of the solder part exposed on the surface of the main board material is
A printed circuit board characterized in that a step is provided at the same level as or lower than the surface of the main board material.