JPS6011649Y2 - Case for mounting LSI chip - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a multi-terminal LSI chip mounting case that is compact and does not have any terminals protruding into space.

A conventional case of this type has a structure as shown in FIG.

A shows a plan view, B shows a side view, and C shows a back view.

The connection terminal 1 does not have a structure that protrudes into space, but has a membrane shape,
They are arranged on the periphery of the back surface of the case, keeping an equal distance of 1.02wrL or 1-27TIrIR from adjacent terminals.

This terminal section passes from the back surface to the side surface, extends inside the case to the terminal extraction section 2, and is connected to the LSI chip within the cavity 3.

In the above configuration, as the number of LSI terminals increases, the outer size of the case also increases, making it difficult to achieve high-density packaging. When a connection is made by soldering, shear stress is applied to the soldered joint due to a difference in expansion or contraction between the case and the board due to changes in the environmental temperature surrounding the case-mounted board.

This stress gradually increases as the case becomes larger.

Due to repeated environmental temperature changes, shear stress causes fatigue in the solder at the connection part, and in large cases with multiple terminals, there is a drawback that the reliability of the connection decreases.

The present invention is characterized in that a new auxiliary terminal is provided inside the conventional connection terminal on the back of the case, and a matching check terminal is provided on the surface of the case, and these are connected with a through hole. , which enables high-density mounting to accommodate the increasing number of terminals in LSIs, reduces the stress applied to each solder joint, improves the reliability of connections in large cases with multiple terminals, and improves visual inspection of connections. An object of the present invention is to provide a case for mounting an LSI chip that enables inspection.

The present invention will be explained in detail based on the drawings.

Figure 2 shows the case for mounting the LSI chip of the present invention.
shows a plan view, B shows a side view, and C shows a back view.

1, 2.3 indicate the same as the conventional one. Reference numeral 1 denotes a connection terminal, which is connected to a mating connection check terminal 4 on the surface of the case through a through hole 5.

The through hole 5 is a cylindrical hole that penetrates the inside of the case, and its surface is made of a conductive material that has good wettability with solder.

Reference numeral 6 denotes an auxiliary terminal, which is similarly connected to a connection check terminal on the surface of the case through a through hole.

With the above structure, by using the auxiliary terminals as LSI electrodes, the case area can be reduced to approximately 1/3 compared to the conventional case, and high density packaging can be achieved.

Fig. 3 shows a comparison of the case area of the conventional case and the case area of the case with auxiliary terminals as the number of terminals changes.

The solid line is the conventional case, and the broken line is the case of the present invention.

Further, when mounting the case on a board, preliminary solder is applied to the board terminals, and the case is placed on top of the pre-solder and heated to melt the solder and connect.

If the connection terminal has a through-hole structure, a portion of the molten solder will be drawn into the through-hole, so you can easily check whether the solder is connected to the board or not by looking at the check terminal from the top of the case. connection inspection becomes possible.

Furthermore, since the structure has auxiliary terminals, when connecting a case and a board with different coefficients of thermal expansion, the temperature will change due to changes in the environmental temperature.
It is possible to reduce the stress per terminal that occurs in the solder connection portion.

As a result, it is possible to suppress solder fatigue that occurs in the soldered joint due to repeated contraction and expansion of the case and the board due to repeated changes in environmental temperature, and to improve connection reliability.

As explained above, since the present invention has a structure in which connection terminals are provided in multiple rows at the periphery and further inside the periphery, a relatively large number of terminals can be provided in a small case, increasing the packaging density. Can be done.

Furthermore, due to the difference in thermal expansion coefficient between the case and the board, the stress generated in the solder connection due to repeated changes in environmental temperature is reduced, and the stress per terminal is reduced, suppressing solder fatigue, thereby improving connection reliability.

Furthermore, by connecting the connection terminal, the auxiliary terminal, and the connection check terminal with through holes, there is an advantage that the connection between the case and the board can be visually inspected and becomes easy.

[Brief explanation of the drawing]

Figures 1A, B, and C are a plan view, a side view including a cross section taken along a-a', and a back view of a conventional LSI chip mounting case, and Figures 2A, B, and C are the case of the present invention. , a side view including a cross section taken along line bb', a back view, and FIG. 3 are characteristic diagrams showing the relationship between the number of terminals and the case area. 1... Connection terminal, 2... Terminal extraction part, 3... Cavity, 4... Terminal for checking connection, 5... Through hole, 6...
・Auxiliary terminal.

Claims (1)

[Scope of utility model registration request] In an LSI chip mounting case that does not have connection terminals protruding into space for connection to a board on which multiple components are mounted, a film-like conductor with good wettability with solder is used to connect to the board. In addition to the periphery of the back surface of the rectangular case, island-shaped connecting terminals are provided inside the rectangular case to form multiple rows of connection terminals, and the surface of the case has multiple rows of connection terminals provided on the back surface of the rectangular case. A check terminal having the same positional relationship as the terminal is provided, and the front and back terminals are connected by a through hole, and the end surface of the through hole is made of a conductive material that is easily wetted with solder. A case for mounting an LSI chip.