JPH02309619A - Manufacture of electronic component - Google Patents

Abstract

PURPOSE:To prevent solder from flowing out to a lead terminal and hence improve productivity upon forming in joining a terminal connecting electrode with the lead terminal using the solder, by masking a soldered portion with a heat-resistant, corrosion resistant material. CONSTITUTION:In dip soldering of a terminal connecting electrode 2 formed on an insulating substrate 1 with a lead terminal 3, a solder 5 pool surface is covered with a mask 4 of a heat-resistant, corrosion resistant material such as stainless through which a hole is formed slightly more widely in its outer periphery than a projection view of component previously impregnated in the solder pool. The hole 7 is impregnated with the purposed component for soldering. Thereupon, the component enters the mask opening part 7 and hence a gap between the ends of the component and the mask 4 is narrowed. Further, since the surface tension of the solder 5 is high, the amount of the solder 5 entering that gap is limited in itself. Hereby, the connecting solder 5 is prevented from flowing out in a large amount along a lead terminal surface and permits highly reproducible soldering to be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing an electronic component with lead terminals in which lead wires are soldered to terminal connection electrodes on an insulating substrate.

Conventional technology As a terminal connection method for electronic components with lead terminals.

Solder connections have traditionally been most commonly used, and their applications are extremely wide-ranging, including hybrid IC1 resistor networks and various filter elements.

One of the specific methods is a contact method such as a jet method or an immersion method. In addition, in recent years, in order to respond to the miniaturization and finer pitch of electronic components, technological development of non-contact soldering methods, typified by light beam methods and laser beam methods, has become very active.

The lead frame that is soldered to the electrode on the board has a
In order to ensure solder wettability, those coated with tin plating or solder plating are often used.

Further, the lead terminals soldered to the electrodes on the substrate are generally formed into a gull-wing type or J-lead type or cut into a predetermined size like a surface mount type component.

Problems to be Solved by the Invention However, the above-described conventional techniques have the following problems.

First, when soldering electrodes and lead terminals on an insulating substrate, the connection solder flows out along the surface of the lead terminals, resulting in uneven thickness of the lead terminals. It was easy.

Second, when terminal forming or molding is performed after lead terminal soldering, the formation of the solder flow layer accelerates the wear of the forming die and the mold die, shortening the life of the die. I had a problem. Also.

This method has disadvantages in that a large amount of solder waste is generated, resulting in lower yields and significantly lower workability.

Thirdly, due to variations in the thickness of the solder flow layer, the load applied to the terminals during forming and molding becomes non-uniform. As a result, the terminal adhesive strength deteriorates, and the forming accuracy of the lead frame decreases.On the other hand, in mold forming, defects due to leakage of resin material due to poor mold adhesion, poor precision of the inner method, and metallurgy occur. The drawback is that the mold itself wears out.

A fourth problem is that the mountability on the glint board is degraded in both cases of insertion-type components and mounting-type components. Specifically, in the case of an insertion type component, the lead terminal plate thickness increases due to the leaked solder layer, resulting in insertion failure. In the case of surface-mounted components, there has been a problem in that the mounting accuracy of the mounter and the like is reduced due to the reduction in forming accuracy, resulting in frequent occurrence of soldering defects.

Fifth, with the recent trend toward lighter, thinner, and shorter lead terminals, lead terminal pitches have become increasingly finer, which has led to frequent problems of bridging of terminals due to solder flow, which is also a cause of yield deterioration.

Sixth, solder leakage increases the consumption of that solder, which inevitably causes losses in terms of resources and management.

In view of the above drawbacks, the present invention aims to improve productivity during forming by preventing solder from flowing to lead terminals, and to provide uniform products with reproducibility in terms of productivity and quality. be.

Ninth Means for Solving the Problems In order to solve the above problems, the present invention provides a method in which the front surface of an insulating substrate is connected to a terminal connection electrode formed on the back surface or both surfaces by soldering to the terminal connection electrode. A heat-resistant and corrosion-resistant material such as stainless steel, which has a lead terminal and has a hole slightly wider on the outer periphery than the projection of the component to be immersed in the solder bath in advance for dip soldering of the terminal connection electrode and the lead terminal. Soldering is performed by covering the surface of the solder bath with a mask and immersing the target component into the hole.

Effect: When the electrodes on the insulated substrate and the lead terminals are soldered using the method described above, the parts are inserted into the openings of the mask, and the gap between the ends of the parts and the ends of the mask is narrow.
Moreover, since the surface tension of solder is large, the amount of solder that can enter the gap is naturally limited. This prevents a large amount of connection solder from flowing out along the surface of the lead terminal, and allows soldering with good reproducibility. This method takes advantage of the property of extremely large surface tension of solder, and the condition of the solder surface (if it is a jet type, the condition of the solder waves and their height and height, and if it is a static bath, the condition of the solder waves and its height). It is not subject to restrictions such as strict management conditions, etc.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 are cross-sectional views of a soldering method according to an embodiment of the present invention. In FIG. 1, numeral 1 indicates an insulating substrate, and materials such as 96% alumina inorganic ceramics and glass epoxy substrates are often used. 2 indicates a terminal connection electrode, which is generally made of Cu, Mug, Pd-A.
g material is used.

3 indicates a lead terminal, which is made of bronze, 4270I, or the like. 4 is a mask used for soldering according to the present invention, and is made of a heat-resistant and corrosion-resistant material such as stainless steel.

5 indicates a solder for attaching a terminal, and eutectic solder or high-temperature solder is often used. 6 is a guide for preventing parts from floating. Here, solder is about to enter the gap between the lead terminal 3 and the mask opening 7, but the amount of solder 5 is restricted by the surface tension of the solder 5. FIG. 2 shows the state of the component before it is immersed in the solder solution.

FIGS. 3 and 4 are diagrams showing embodiments of the electronic component of the present invention. The one in the figure is the third one.
In the parts of the structure shown.

Lead terminals 31 &: This is an example where the leads are pulled out in the same direction.

Detailed Description of the Invention As described above, the present invention is a soldering manufacturing method that utilizes the extremely large surface tension of solder. It is possible to uniformly solder the target part without being constrained by conditions (such as strict control of height in the case of a static bath, etc.), and it is possible to join with the minimum amount of solder required.
Furthermore, solder leakage to the outside can be prevented, and as a result, productivity can be improved by reducing the generation of solder waste during forming and molding, and there is little deterioration in terminal strength, resulting in improved terminal dimensional accuracy and mounting performance. Excellent in terms of production, which also extends the life of the mold.

It has great practical effects in terms of quality and cost.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of a soldering method in an electronic component manufacturing method according to an embodiment of the present invention, and FIGS. 3 and 4 are respectively sectional views of an electronic component manufacturing method according to an embodiment of the present invention. FIG. 3 is a sectional view showing a soldering method in FIG. 1...Insulating substrate, 2...Terminal connection electrode, 3...Lead terminal, 4...Mask, 5...Solder, T・・・・・・Mask opening. Name of agent: Patent attorney Shigetaka Awano and 1 other person3-
- Zord Edition Chi Figure 2 Figure 3 rA etc.

Claims (1)

[Claims] an insulating substrate, a terminal connecting electrode formed on a front surface, a back surface, or both surfaces of the insulating substrate, and a lead terminal connected to the terminal connecting electrode by soldering, the terminal connecting electrode and the lead terminal; 1. A method of manufacturing an electronic component, which comprises masking the soldered part with a heat-resistant and corrosion-resistant material during soldering.