JPS61256693A - Soldering of printed wiring board and lead electronic component - 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 Field of Industrial Application The present invention relates to a technique for assembling circuit boards used in electronic equipment, and in particular, a method (hereinafter referred to as Soldering is called a method.)
Regarding.

Conventional technology A component lead wire is inserted from one side into a hole in a board such as a paper-based phenolic resin laminate, a glass cloth-based epoxy resin laminate, or an alumina porcelain board, and the other side of the board is brought into contact with molten solder liquid. over the conductor land on the bottom of the board and the lead insertion part,
Methods of forming solder joints are widely used today. The first function of this method is to supply solder.
The second function is to cause the molten solder to raise the temperature of the metal to be joined by heat conduction to a temperature higher than the solder melting temperature.

Problems to be Solved by the Invention The disadvantage of this method is that because heat is transferred by the solder, the time for the parts to be joined to reach a predetermined temperature varies depending on the location. .)
Solder should not completely intrude between the two. Furthermore, the through-hole plated portions are not filled with enough solder, which tends to cause air bubbles to be adsorbed inside and voids such as gas release holes to occur.

Means for Solving the Problems The present invention provides a method of drilling holes in wiring conductor lands of a printed wiring board,
In the method for inserting a lead electronic component into the hole and soldering it to the wiring conductor on the lower surface, after bonding solder paste to the wiring conductor land on the lower surface of the printed wiring board, the lead electronic component is inserted into the hole on the upper surface. It is inserted into the lower surface and heated from the lower surface side with a liquid heating medium to melt and solder the solder paste, the liquid heating medium being high temperature oil or molten solder, and in the medium, The wiring conductor land is immersed and heated.

Effects of the present invention The solder paste and the lead wires of the lead electronic components are heated by the heating from the bottom side of the board by the liquid heating medium, and the land surface of the board and the lead wires to be joined are heated by the 7 lux in the solder paste. The surface is cleaned,
The solder in the solder paste adheres easily and the soldering is completed.

Embodiment Figures 1 (IL) to (d) show that the soldering method of the present invention is the first method.
and a process diagram of the second embodiment, and FIG. 2 shows a completed sectional view based on the first and second embodiments.

First, a first embodiment will be explained.

(For one-sided copper foil printed wiring board (1) made of a paper-based phenolic resin board with a thickness of 1.6W as shown in →)
As shown in b), commercially available solder paste (tin/lead = 63
/37) (Print 41 by screen printing method. Heat the board (1) at 80°C for 30 minutes to fix the solder paste (4). As shown in (0), place the wiring conductor land facing down. As shown in (d), insert the electronic component lead (6) from the top of the board (11) and place the lead electronic component (5). Eutectic semi-EEI of tin/lead ±63/37
When (7) is heated and melted at 260°C and the - wiring conductor land (3) is brought into contact with the surface, and the solder paste (4) and lead wire (6) are heated from the eutectic solder (7), the solder paste ( 4) The 7 luxes in the middle clean the wiring conductor land (3) surface of the board (1) and the bonded surface of the lead (6), and the solder in the solder paste (4) easily adheres.
A solder alloy (9) is formed as shown in FIG.

Next, a second embodiment will be described.

The board shown in (&) is made of an alumina porcelain plate with a thickness of 0.6 Lu and has silver powder and palladium powder printed on one side (
1)) As shown in Figure 1(b), soldering is first done using a commercially available solder paste (tin/lead/silver) on the land (3) around the planned lead wire insertion hole (2). =60/3
7/3) (Print 41 by screen printing method. Heat the board (1) at 80'C for 30 minutes to fix the solder paste. As shown in Figure 1 (Q), print the wiring conductor land (3). ) facing down, insert the component lead (6) from the top of the wiring board as shown in Figure 1 ((L)),
Place the lead electronic component (5). The wiring conductor land portion (3) is brought into contact with the surface of the silicone oil (7) heated to 230C in the container (8), and the solder paste (4) and leads are removed from the oil (7). When +6) is heated, the 7 lux in the solder paste cleans the wiring conductor land surface (3) of the board and the bonded surface of the linide fj [(61), allowing the solder in the solder paste (4) to easily adhere. Then, a solder joint (9) is formed as shown in FIG.

It is also possible to apply oil immersion to a paper-based phenolic resin substrate and to apply solder immersion to an alumina porcelain plate.

Effect of the invention The present invention produces the following effects.

(1) Good solder filling rate between leads and lands. In other words, as a test single-sided printed wiring board of 100 x 55 m7tn, the hole diameter is 0.8 rry'm.
φ, land diameter 2- Omumφ hole and land are machined,
In Examples 1 and 2, the average value of the solder filling rate and blow hole rate of 100 boards into which 10 ceramic capacitors each having 5-J-pitch and 0.6 Jzφ diameter leads were inserted was the same as that of the conventional example. It is improved as shown in the table below.

(2) According to this method, the usual process of applying 7 lux immediately before heating by solder immersion or oil immersion is omitted.

(3) As a liquid medium, contact with a high temperature silicone oil liquid provides even better results than molten solder. Silicone oil liquid has good thermal conductivity, is a good heating medium, and has a high heat resistance. Furthermore, there is no formation of surface oxides that occur in the case of molten solder baths, and the effort of removing oxides immediately before soldering is eliminated.

(4) Especially for the silver electrode land of the alumina porcelain plate,
If oil immersion is applied, there will be no corrosion of silver due to immersion solder, increasing reliability as a conductor.

(5) As a heating method, there is also a method of heating the upper surface and the lower surface with atmosphere or infrared rays, but this is not preferable because it causes thermal damage to the components arranged on the upper surface. Short-time heating from the bottom surface not only reduces or shields the printed wiring board from thermal effects on the components, but also prevents the printed wiring board, especially its through-hole plating, from being thermally cut.

[Brief explanation of the drawing]

1(a) to (d) are process diagrams of the first and second embodiments of the soldering method of the present invention, and FIG. 2 is a completed sectional view based on the first and second embodiments. show. 1: Board 2: Hole 3: Wiring conductor land 4: Solder paste 5: Component body 6: Component lead 7: Heating liquid medium (molten solder or high temperature oil) 8: Container for heating liquid medium 9: Half FB valley metal

Claims (1)

[Scope of Claims] 1. In a method of forming a hole in a wiring conductor land of a printed wiring board, inserting a lead electronic component into the hole, and soldering it to a wiring conductor on the lower surface, After bonding a solder paste to the wiring conductor land, the lead electronic component is inserted into the hole from the top side to the bottom side, heated from the bottom side with a liquid heating medium to melt the solder paste, and the lead electronic component is A method for soldering printed wiring boards and lead electronic components by soldering components and wiring conductor lands. 2. The liquid heating medium is high temperature oil or molten solder,
The method of soldering a printed wiring board and a lead electronic component according to claim 1, wherein the wiring conductor land is immersed in the medium and heated.