JPH0268953A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enable water content to be dissipated easily and prevent crack due to rapid thermal expansion etc. from occurring even if there is water content at the interface between the rear surface of a tab lead and a resin by exposing one part of the rear surface of the tab lead for loading a semiconductor chip and resin-sealing the entire area of other parts. CONSTITUTION:By exposing one part of a rear surface of a tab lead where a semiconductor chip 3 is mounted to the surface, the other part of the rear surface of the tab lead 10 and the entire area at the surface side of the tab lead 10 covering the semiconductor chip 3 are resin-sealed. For example, after connecting the semiconductor element 3 onto the tab lead 10 of a lead frame electrically, each terminal part of an external lead 1 and the semiconductor element 3 is connected electrically. Thus, the lead frame where the semiconductor element 3 is incorporated is set onto a seal lower mold machined so that one part of the rear surface of the tab lead 10 may be exposed, a seal upper mold 9 is lowered for closing the mold, and then a seal resin 5 is injected into a cavity for sealing resin.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a semiconductor device, and particularly to a thin resin-sealed semiconductor device.

Conventional Technology When electrically connecting a thin resin-sealed semiconductor device to a printed circuit board, a method called solder reflow is used. For example, the semiconductor device is placed in a predetermined position on the printed circuit board, and The printed circuit board and the semiconductor device were electrically connected by passing through a high temperature furnace at 230°C. This was fine if the semiconductor chip had a small area, but as the degree of integration has improved in recent years, the area of the semiconductor chip has increased, and the tab lead surface on which it is placed has also increased in diameter, making it difficult to use resin in the solder reflow process. Moisture absorbed by the encapsulated semiconductor device exists at the interface between the back surface of the internal tab lead and the resin, causing rapid thermal expansion and causing cracks in the encapsulating resin portion. Conventionally, as a countermeasure against this problem, a large number of concave holes were formed on the back side of the tab lead to strengthen the adhesive force between the tab lead and the resin, thereby reducing the occurrence of cracks.

Problems to be Solved by the Invention In the conventional example, cracks in the thin resin-sealed semiconductor device were prevented during the reflow process by changing the shape of the back of the lead frame of the thin resin-sealed semiconductor device, especially the tab lead. As the number of semiconductor chips increases in recent years, it has become impossible to remove moisture existing at the interface between the back surface of the tab lead and the resin using conventional techniques.

Means for Solving the Problems In order to solve the problems described above, the semiconductor device of the present invention is provided by exposing a part of the back surface of a tab lead for mounting a semiconductor element and sealing the entire other part with resin. It is a structure.

Function: According to such a semiconductor device, even if moisture is present at the interface between the back surface of the tab lead for mounting a semiconductor element and the resin, it is easily removed because a part of the back surface of the element mounting plate is not covered with resin. Moisture is released, making it possible to prevent cracks from occurring due to rapid thermal expansion or the like.

Embodiment The present invention will be described in detail with reference to the semiconductor device shown in FIGS. 1 and 2 and cross-sectional views of its manufacturing process. As the material of the element mounting plate, so-called tab lead 10, for example, an iron alloy such as aloitin, Kovar, or steel may be used. Furthermore, the upper and lower sealing molds 8 and 9 may be made of, for example, an iron alloy. To explain the sealing process procedure, the semiconductor element 3, which has undergone a predetermined diffusion process, is divided by, for example, a dicing saw or the like, and a predetermined interval is left in order to facilitate mounting. Next, the semiconductor element 3 is electrically connected to the tab lead 10 of the predetermined lead frame by applying heat treatment or the like using, for example, a conductive paste, and then, using, for example, a gold wire 4, The external lead 1 of the lead frame and each terminal portion of the semiconductor element 3 are electrically connected. In this way, the lead frame in which the semiconductor element is installed is set on the lower sealing mold 8 which has been processed so that a part of the back surface of the tab lead 10 of the lead frame is exposed, and the upper sealing mold 9 is lowered. Close the mold and inject the sealing resin into the cavity. after that,
After waiting for the resin to harden, the mold is opened and the lead frame is taken out, completing the sealing process. In addition, the processing of the mold is
Either the top or bottom is fine.

Effects of the Invention According to the present invention, in a thin resin-sealed semiconductor device,
Since a part of the tab lead for mounting the element is not sealed with resin and is exposed, moisture existing at the interface does not accumulate unnecessary stress due to rapid thermal expansion.
Since it is freely released to the outside, it prevents the occurrence of cracks in processes that involve heat treatment such as solder reflow, and it also makes it possible to prevent the occurrence of cracks at no cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a thin resin-sealed semiconductor device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a mold portion during the resin-sealing process. 1...Lead frame, 2...Die attach section, 3...Semiconductor chip, 4...
・Lead wire, 5...Resin, 6...
Tie bar, 7... Frame, 8... Lower sealing mold, 9... Upper sealing mold, 10...
・Tab lead for mounting elements. Name of agent: Patent attorney Shigetaka Awano and one other person Figure 1 Figure 12! -1-m- -15-・--1-18-・9-・-n −- J-de frame die attach part Bar - Frame lower tLSI sealing upper mold element mounting plate

Claims (1)

[Claims] A semiconductor device characterized in that a part of the back surface of a tab lead on which a semiconductor chip is mounted is exposed, and the other part of the back surface of the tab lead and the entire surface side of the tab lead that covers the semiconductor chip are sealed with resin. .