JPS6086892A - Circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to circuit boards, and more particularly to solder mounts for circuit boards used in hybrid integrated circuits, modules, and the like.

[Technical background of the invention]

The circuit boards used in hybrid integrated circuits and modules, etc.
The insulating substrate is made of a material such as alumina or GALAEVO (Gepoxy resin with glass fibers), and the wiring pattern formed on its main surface is connected to a solder land layer provided near the periphery of the main surface. . This solder land layer is formed of a thick conductive metal layer such as copper foil or silver base. 1st
The figure shows the solder land layer. In the figure,
(1) is an insulating substrate, (2) is a solder land layer, (3)
The solder resist layer is coated on the entire surface of the insulating substrate including the wiring pattern (4), excluding the solder land layer (2) and other areas where solder layer formation is required. Note that the above solder resist layer is not essential.
Sometimes the tore is omitted.

2. Description of the Related Art Some conventional circuit boards are illustrated in FIGS. 2 to 6, for example. As shown in FIG.
2) Printed solder layers (5), (5)... with a thickness of 0.2 to 0.3 m (1) are formed by the solder printing method, and round lead wires (6), (61...
・A chip capacitor (7), etc. are mounted (Figure 3). However, in this situation, the amount of solder is appropriate for items such as chip capacitors that are soldered together between two flat surfaces, but for items such as round leads, the amount of solder that surrounds the leads is obvious. The solder joint strength is poor. Therefore, solder 70 to this
Even if - is applied, the solder layer (5') remains as shown in Fig. 4?
(5')... is insufficient.

Therefore, after mounting the components as shown in Figure 3, replenishing the solder land layer with insufficient solder amount as shown in Figure 5 to make the solder layer ◇, and performing solder reflow, as shown in Figure 6. A good solder joint is achieved with the solder layer (15') as shown in FIG.

[Problems with background technology]

In order to increase the amount of solder on the solder land, a solder layer (c) is provided on the solder land layer (2) protruding from it as shown in FIG.
As shown in Figure 8, the solder layer (25) sufficiently wraps the lead (6) placed on the solder land (2), and the periphery of the solder layer (c) protruding from the solder land (2). A part of the solder is separated into spherical solder (257/). This spherical solder does not contribute to the solder joint.

As a next method, it is possible to increase the thickness of the solder provided on the solder land from the usual 0.2 to 0.3 m to 0.5 m, but it is possible to increase the thickness of the solder provided on the solder land from the usual 0.2 to 0.3 m, but it is possible to increase the thickness of the solder provided on the solder land from the usual 0.2 to 0.3 m. Solder is wasted on the lands on which the chip capacitors (7) are mounted, and solder bridges and short circuits occur on adjacent precision patterns.

[Purpose of the invention]

The present invention overcomes the problems of the prior art and provides a circuit board with an improved structure of solder joints.

[Summary of the invention]

In the circuit board according to the present invention, components are mounted on a solder land layer printed on the main surface of an insulating board, and the components are mounted by solder reflow.The solder land layer of the circuit board extends outward from the line. It is characterized by having a shaped pattern.

[Embodiments of the invention]

Next, the present invention will be explained in detail with reference to FIG. 9 and subsequent figures for one embodiment of the circuit board.

In Fig. 9, (1) is an insulating substrate made of Gala Evo (glass-filled epoxy resin), 7 Ale, alumina, etc., and a thick conductive metal layer such as copper foil or silver base is formed on the top surface of the insulating substrate. A wiring pattern (4) and a solder land layer a4 are formed, and the area except the top of the solder land layer is covered with a transparent solder resist (3).

The solder land layer ano has a rectangular solder land base (12a) of the same type as the conventional solder land layer (2), and a tentacle-shaped solder land base (12g) extending outward from the solder land base (12g). pattern stripe (12b), Q2b)...
・Consists of.

Next, the process of performing solder bonding using the insulating substrate will be explained with reference to FIGS. 10 to 12.

A solder land layer (1) is provided on the main surface of the insulating substrate (1), and the areas other than the solder land layer are covered and protected with a solder resist layer (3) (FIG. 1O).

Next, a printed solder layer (35) is applied to the solder land layer.

(35)... is formed. In this case, not only the solder land base (12g) of the printed solder layer but also the pattern stripes (12b) extending from the solder land base (12g), (
12b)...The printed solder layer is continuously coated on the top and also on the solder resist layer in the area sandwiched by the pattern stripes (FIG. 11).

Next, parts to be placed, such as leads (6), (6), etc., are placed on the printed solder layers (35), (35), and then solder reflow is applied to the solder layers (35). ')
, (35')... is formed.

Since the area of the printed solder layer is expanded in advance from the base of the conventional solder land, the amount of solder is sufficient. That is, the amount of solder deposited on the printed solder layer that protrudes beyond the base of the solder land flows back to the base of the land via the pattern stripes and is replenished.

Note that this invention applies to the solder land layer shown in FIG.
, may be formed as desired. These examples show three and five pattern stripes extending from the solder land base, respectively.

Furthermore, as shown in FIG. 14, a solder land layer (4 ri) in which the pattern stripes extend and then are bent, or a closed solder land layer in which the pattern stripes extending at intervals are bent and connected. It may also be used as a land layer 6a.

Next, when forming a solder land layer, the invention of 2009-2011 does not particularly form pattern stripes, but rather forms a wide area including the pattern stripes and areas sandwiched or surrounded by these. (FIG. 15), it is also possible to form the pattern stripes only from the solder resist layer (FIG. 16) when forming the solder resist layer (3).

〔Effect of the invention〕 .

According to the circuit board according to the present invention, it is possible to avoid inaccurate solder replenishment by a dispenser, thereby shortening the process, and there are significant effects such as avoiding short circuits between circuit patterns due to an excessive amount of solder.

[Brief explanation of drawings]

Figure 1 is a front view showing the structure of the circuit board, Figures 2 to 6 are each (,) figure explaining the process of soldering components to the circuit board, and each (b) figure is a front view. is a cross-sectional view, the seventh
8 and 8 are front views for explaining one conventional means of forming a solder layer on a solder land, and FIG. 9 and subsequent figures show examples of the present invention, and FIG. Figures 10 to 12 are front views showing the process of soldering parts to the circuit board, and Figures 13 to 16 are part of the circuit board for explaining another embodiment. FIG. 1 Insulating board 3 Solder resist 6.7 Parts (leads, chip capacitors) 12, deaf,
32, 42 series Solder land layer 12g Solder land base 12b Pattern strip 35 Printed solder layer 35' Solder layer (after reflow) Agent Patent attorney Inoue - Male Figure 1 Figure 2 (α) (b) 8 Figure 4 (α) Cb Figure 6 (α) (b) Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 15 Figure 14 Figure 16

Claims (1)

[Claims] The solder land layer of the circuit board, on which components are mounted on the solder bond layer printed on the main surface of the insulating substrate and the components are mounted by solder reflow, has a pattern portion extending outward from the solder land layer of the circuit board. A circuit board characterized by: