JPS5844597Y2 - Lead structure for IC package - Google Patents

Description

[Detailed description of the invention] The present invention provides an outer protective case for semiconductor ICs, commonly known as a plug-in type package.
Regarding the lead pin structure that is applied to the connection process inside the pack when formatting the package.

In recent years, with the increase in the degree of integration of IC chips such as semiconductors, the number of connection lead terminals (hereinafter simply referred to as leads or lead pins) per unit package has also increased to 50 or more. Equipment introduction requires efficient implementation in plug-in format.

The present invention is intended for such mounting conditions, and proposes a lead structure that can efficiently and with high bonding strength realize brazing bonding between lead pins and IC chip lead-out conductors (hereinafter referred to as lead patterns) inside the package body. It is something.

FIG. 1 is a perspective view and a partial sectional view of the overall structure related to the conventional brazing process.

Figure 8 is a perspective view of the package body with the top cover removed, figure 8 is a sectional view of the main parts to be joined, and figure 8 is a plan view of the lead pattern pre-metalized on the substrate of figure 8.

In the figure, 1 indicates the IC chip, 2 and 3 indicate the lead pattern and the solder 1 joint location where the lead pattern 2 and the lead pin are joined.Of course, the location 3 is a hole slightly larger than the lead pin diameter tolerance. are arranged in a large number.

And 4 is a ceramic substrate made of alumina composition or the like.

FIG. 8 shows the cross-sectional structure of the joint portion of the above-mentioned portion 3, and the conventional processing method will be briefly explained with reference to this figure.

5 is a lead pin, and the head of the lead pin is designed to crush the end face with a header as shown in the example to ensure stable bonding strength.

For the lead pin 5, an alloy pin of iron (Fe), nickel (Ni), or cobalt (Co), which has high mechanical strength, is used rather than a general annealed copper wire.

The lead pin 5 is attached to the joint portion 3 of the lead pattern 2. At this time, the lead pin 5 and the lead pin 5 are inserted through a brazing piece formed into an appropriate shape, for example, a ring-shaped piece 6 as shown.

Instead of using the ring-shaped piece 6, it is also possible to apply a thick film of paste-like solder material on or around the surface of the lead pattern 5.

As described above, conventionally, when joining the lead pins 5, the lead pins and the solder material are separately prepared and set on the lead pattern, which has the disadvantage of requiring a very large number of man-hours in proportion to the number of lead pins.

Furthermore, when the lead pins are set through the ring-shaped pieces 6, there is a problem in that the lead pins may come out from the ceramic substrate 4 during the subsequent brazing process, resulting in poor brazing.

The present invention was developed to solve this problem, and its feature is that plug-in type IC packaging is performed on an insulating substrate such as a ceramic. There is a lead structure for an IC package in which the heads of the lead pins involved are previously clad with a bonding filler material.

Hereinafter, the lead structure of the present invention will be described in detail with reference to FIG. 2.

5 in the figure is a lead pin with the head shape of the opening in Figure 1, and on the head surface there is silver (Ag) and copper (
A brazing material 7 made of a Cu) eutectic alloy is mechanically pressed and caulked and installed as a so-called cladding.

The cladding is carried out in a process subsequent to the header processing.

The thickness of the cladding layer is determined in advance by taking into account the minimum amount required at the junction, but it is approximately 30 to 50 μm (1 micron).
0 'cm) is also sufficient.

If the lead structure is rudd-treated like this, the complexity of the conventional work will be eliminated.

That is, the joining lead pin 5 is inserted into the ceramic substrate 4 at the joining location, and after insertion, the surface of the lead head is leveled, followed by a brazing process at about 800 DEG C., and the joining as shown in FIG. 3 is completed.

Although adoption of the lead structure requires a new brazing cladding process, it is clear that the work of joining lead pins, lead patterns, and bonding is simplified, contributing to an overall reduction in packaging man-hours.

In the figures cited in the above explanation, for example, the lead-doped pin is explained as having a circular cross section, but it may also be composed of a lead plate with a rectangular cross section, and there are no illustrated examples of the cladding shape, etc. It is not limited to.

[Brief explanation of the drawing]

Figure 1A is a perspective view of a package with a conventional configuration, the opening in the figure is a sectional view of the main part of the joint, Figure C is a plan view of the lead pattern pre-formed on the substrate 4 in Figure 8, and Figure 2 is A cross-sectional view showing the lead structure according to the present invention and FIG. 3 are cross-sectional views showing a state in which the bonding is completed. In the figure, 1...IC chip, 2...lead pattern, 3...junction, 4...
Ceramic board, 5/curve/lead pin, 6...
Ring-shaped brazing material, 7...Curved cladding brazing material.

Claims (1)

[Scope of utility model registration request] In the bonding configuration between a lead pin and a lead pattern for plug-in type IC packaging on an insulating substrate such as a ceramic, the head of the node pin involved in the bonding is preliminarily clad with a bonding filler material. IC
Lead structure for packaging.