JPH02220382A - Soldering clip lead - Google Patents

Abstract

PURPOSE:To increase the mounting density of chip parts to a circuit board by installing a solder-resistant thin and flat spacer in such a way that its slit encloses a circuit board along the thickness of the circuit board, and immersing lead electrode parts in fused solder. CONSTITUTION:For chip parts 5, the clip part of a clip lead 3 is engaged with lead electrodes 2 of a circuit board 1 applied by reflow soldering, and a space 6 of a glass epoxy plate is inserted between the clip leads and part electrodes of mounted chip parts. The part of the lead electrodes 2 is then immersed in fused solder 8 in a solder tank 7, while completely preventing direct contact of the solder part of the chip part 5 mounted on the circuit board 1 with the fused solder 8. The mounting density of chip parts to the circuit board can thus be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for soldering clip leads that can be employed in the manufacturing process of hybrid integrated circuit devices. The present invention relates to a method for soldering clip leads that can be conveniently employed in cases such as soldering leads, and which also has the advantage of improving the packaging density of chip components.

[Prior art] Conventionally, the production of hybrid integrated circuit devices with leads involves printing cream solder on the component capacitors of the circuit board, mounting the chip components, and heat-treating them in a reflow oven to attach the chips to the components. After the components have been soldered, they are soldered to lead electrodes provided on the edge of the circuit board using a clip-lead dipping method. In this dipping method, the tip of the lead is placed downward, and the substrate is immersed in molten solder until the lead electrode is completely buried. The molten solder wets the lead electrode with the clip lead attached, and after the board is pulled up from the solder bath, the solder hardens and the clip lead is soldered to the lead electrode of the board.

[Problems to be Solved by the Invention] However, when soldering a clip rete to a lead electrode of a hybrid integrated circuit board using the above-mentioned conventional method, for example, as shown in FIGS. 2 and 3, When the distance d between the lead electrode 2 provided on the edge and the soldered part of the chip component 5 mounted on the circuit board surface d is narrowed, the clip lead 3 is attached to the lead electrode 2. In the process of soldering the circuit board l
When the edge of the chip is immersed in the molten solder, at least a part of the component electrode, which is a part of the soldering of the chip component, comes very close to the molten solder liquid level, and sometimes comes into contact with the molten solder liquid level. do. For this reason, the soldered parts may be reheated, the solder may melt, and the mounted chip components may become misaligned or fall off. In order to prevent this, in the conventional method, it was thought that it was necessary to provide an end distance d of at least about 1.5++ m between the lead electrode provided at the edge of the circuit board and the component electrode for mounting the chip component. This distance d ultimately represents the size of the portion where chip components cannot be mounted, that is, the size of the dead space, so that the larger the distance, the more the mounting density of the circuit board is restricted.

It is an object of the present invention to overcome the above-mentioned conventional drawbacks, to provide a method that has substantially smaller dead space than the conventional method, and to prevent thermal effects of molten solder even when chip components are mounted close to the terminal edges of lead electrodes. It is an object of the present invention to provide an improved clip-lead soldering method that can be soldered to lead electrodes of a clip-lead circuit board without causing drop or misalignment of mounted chip components.

[Means to solve the problem]

The clip lead of the clip lead is fitted to the hybrid integrated circuit board board on which the chip component is mounted, and the clip lead is soldered to the lead electrode by immersing the clip fitting part in molten solder. When attaching, between the lead electrode 2 and the component electrode 4 (the part shown by d in FIG. 2), a solder-resistant material (not easily wetted by solder J, excellent in heat resistance, and with low thermal conductivity) is placed between the lead electrode 2 and the component electrode 4 (the part shown by d in FIG. 2). For example, a thin plate-shaped blocking jig with slits made from a glass epoxy plate (for example, a glass epoxy plate)
By attaching a spacer to sandwich the circuit board in its thickness direction with a slit and soldering, the soldering of the chip components mounted on the circuit board can be done by directly contacting the part (on the component bridge) with the molten solder. The above problems were solved by avoiding heat transfer from the molten solder to the mounted chip components and sufficiently blocking the transfer of heat to the parts. That is,
By doing as described above, the distance d between the ends of the lead electrodes 2 and the component electrodes 4 can be made smaller than in the conventional method, and the mounting density of the circuit board can be substantially improved. .

The spacer used in the method of the present invention is a thin flat plate with a long slit wide enough to sandwich a circuit board, and is made of a solder-resistant material that is resistant to solder and has excellent heat resistance and low thermal conductivity. This is a blocking jig. That is, the spacer 6 forms the slit 9 in the thickness direction of the circuit board 111ijl.
It can be easily attached to the board L and fixed vertically to the board, and all parts on the board can be easily attached to the board L! It is a thin plate-like member having a length that can reliably isolate the lead electrodes 4 from all the lead electrodes 2 (see FIGS. 1a and 1b).

[Function] According to the present invention, when clip leads are soldered to the lead electrodes provided on the edge of a hybrid integrated circuit board, the mounted chip components are partially soldered, and the component electrodes and clip leads are partially soldered. Soldering is performed by separating the lead electrode from the lead electrode using a thin flat spacer with a slit made of a solder-resistant material that does not easily get wet with solder and has low thermal conductivity. Contact between the components and the molten solder is avoided, and the heat of the solder is also blocked by the spacer, so the soldering of the mounted chip components can be prevented from remelting, and the spacer is made of a material that does not easily wet with solder. As a result, the molten solder liquid level at the edge of the spacer takes the shape shown in FIG. 1b due to the surface tension of the solder, making it difficult for the heat of the solder to be transferred to the chip components on the circuit board. Therefore, the mounted chip components are less likely to be misaligned or fall off, and the area in which the chip components can be mounted is expanded to areas near the lead electrodes of the circuit board, making it possible to increase the mounting density of the circuit board.

Large--]] L-- Example As shown in FIGS. 5 and 6, the chip component 5' (
The clip part of the clip lead 3 is fitted to the lead electrode 2 of the circuit board l on which the multilayer capacitor 1608 type) is reflow soldered, and the clip part of the clip lead 3 is inserted between the clip lead and the component bridge of the mounted chip component as shown in FIG. A spacer 6 made of a glass epoxy plate was inserted into the spacer. At this time, the distance between the glued electric bridge 2 and the mounting part of the multilayer capacitor 5' is 0.6 mm to 1.5 mm, as will be shown in detail later.
The values were in the range of ++m.

The specifications of the spacer and circuit board used in this example are as follows.

Spacer cross-sectional shape: As shown in Figure 4 Material: Niglass epoxy board Dimensions: J! =70.0mm, w=7.0am,
x=5.0LIa+y=11 units a+u, t=0
．． 5mm (thickness) 0 chips. Appearance: As shown in Figures 5 and 6 Substrate material: Ceramic substrate (AgPd thick film electrode) Dimensions: L = 60.0+*s+, W = 10.0
mm, t' = 0.635mm (thickness) Chip components mounted: Multilayer capacitor 1608 type component Electrode dimensions: 1. Omm X 1. Omm lead? t[i dimension: 1.4m x 1.61mm Lead used: Clip lead 2.54mm Distance between pitch lead electrode and chip component doublet: d=0.6. 0.8.1.0. 1
．． 5. (mm) ■For comparison, a circuit board similar to the above (■) without a spacer was prepared.

■Preheat each circuit board obtained in steps ■ and ■ above (150℃
, 30 seconds), hold the molten solder 8 in the solder tank 7 using a bottle set, etc. so that the arrangement is as shown in FIGS. 1a and 1b.
immersed in it for 3 seconds. The immersion depth was such that the lead electrode 2 was completely immersed. After pulling it up, it was confirmed that the fitted clip lead was completely covered with solder.

■The results obtained above are organized and shown in Table 1. The numbers in Table 1 represent the number of samples. The total number of subjects for each test was 60.

When the glass epoxy temporary spacer 6 is installed between the component t [i4 and the lead wire h2, the number of defective products due to dropping or misalignment of chip components on the circuit board is zero, and the soldering of chip components is only partially performed. The chip components did not come off due to remelting, and the connection between the clip lead and the lead electrode was extremely good. Furthermore, parts type? The distance between the ends of II 4 and lead electrode 2 was also made extremely small compared to the conventional method.

(Blank below) [Effect of R Light] According to the present invention, when soldering a clip lead to a lead electrode provided at the edge of a hybrid integrated circuit board, mounted chip components are exposed to the thermal effects of molten solder. Since the soldering of the chip components is less susceptible to remelting, the mounted chip components are prevented from falling or being misaligned. Further, since the area in which chip components can be mounted can be expanded to areas that are conventionally dead spaces or adjacent to the dome, it is possible to increase the mounting density of chip components on the circuit board.

[Brief explanation of the drawing]

FIG. 1a is a perspective view showing a spacer installed between a lead electrode on an edge of a hybrid integrated circuit board and a component groove of a mounted chip component according to the present invention. FIG. 1b is a conceptual diagram showing a state in which the circuit board shown in FIG. 1a is immersed in molten solder with the board surface vertical. FIG. 2 is a conceptual diagram showing a state in which a part of a circuit board is immersed in molten solder, viewed from the front, in order to solder clip leads to lead electrodes of a circuit board using the conventional method. . FIG. 3 is a conceptual diagram of the state shown in FIG. 2 viewed from the side. FIG. 4 is a diagram showing a cross-sectional shape of an example of a spacer that can be used in the method of the present invention. FIG. 5 is a conceptual diagram showing a state in which a spacer is attached to a circuit board according to the present invention, when the circuit board is vertically viewed from the front. FIG. 6 is a conceptual diagram showing a state in which a spacer according to the present invention is attached between a lead electrode at an edge of a hybrid integrated circuit board and a component electrode of a chip component. The symbols in the figure represent the following: 1-・Circuit board 2・Lead electrode 3・・
・Clip lead 4-・Component electrode 5・-Chip component 5'-Multilayer capacitor 1608 type

Claims (1)

[Claims] When soldering clip leads to the lead electrodes of a hybrid integrated circuit board on which chip components are mounted, a heat-resistant, solder-resistant material that is difficult to get wet with solder and has low thermal conductivity is placed between the lead electrodes on the circuit board and the component electrodes. A thin flat spacer with slits made of material is attached so that the slits sandwich the circuit board in the thickness direction of the circuit board, and the soldered parts of the chip components mounted on the circuit board are connected to the molten solder. A clip lead soldering method characterized by immersing the lead electrode portion in molten solder in a manner that completely prevents direct contact.