JPH02185060A - Lead frame for semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a highly reliable resin-sealed semiconductor device in which a copper oxide film is scarcely formed, and contact strength with resin is enhanced by providing copper and silver mutually diffused layers on the surface of a lead frame. CONSTITUTION:A semiconductor placing unit 6 for placing a semiconductor element and a plurality of leads 7 disposed at a predetermined interval on the periphery of the semiconductor element placing unit 6 are integrally coupled with a leaf frame 5, a thin silver film is formed on the surface of the lead frame 1 and heated to form copper and silver mutually diffused layer 4. Thus, a silver film is formed on the copper face to suppress the generation of a copper oxide film, and copper and silver mutually diffused layer is formed to obtain highly close contact force with chip bonding resin and sealing resin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a semiconductor lead frame on which a semiconductor am circuit (IC) chip or the like is mounted.

[Conventional technology]

As shown in FIG. 3, this type of lead frame for a semiconductor device includes a lead frame frame 5 as a lead frame body divided into a predetermined number of parts, and a semiconductor element supported in the center part of this lead frame frame 5. A mounting part 6 and a plurality of external connection leads 7 for leading out each electrode terminal of a semiconductor element (not shown) mounted on the semiconductor element mounting part 6 to the outside via a wire line. Equipped with The leads 7 are connected to an internal lead part 8 which is arranged radially around the semiconductor element mounting part 6 at a predetermined interval, and which are arranged parallel to each other on the other end side of the internal lead part 8. The external lead portion 9 is made up of an external lead portion 9. Also,
A tie bar IO is integrally connected to the intermediate portion of the leads 7 in order to maintain the stable separation position of the leads and to prevent the resin from leaking to the outside during resin sealing. In addition, in Figure 3, area 1 surrounded by dotted lines
Reference numeral 1 indicates a resin region for semiconductor sealing, and a lead piece 6 forming a part of the semiconductor element mounting portion 6 included in this resin region 11
A is also usually referred to as an internal lead portion.

Next, the operation will be explained. After chip bonding a semiconductor element (not shown) to the semiconductor element mounting part 6, the internal lead part 8 of each electrode terminal lead 7 of the semiconductor element is bonded.
0 Next, in a normal resin sealing process, the internal lead part 8 including the semiconductor element and the wire wire is sealed with resin, and then the frame frame 5 and the tie bar 10 are sealed.
By separating, a resin-sealed semiconductor device is completed.

In recent years, techniques have been developed for bonding such lead frames directly to the copper or copper alloy lead frame material or via a copper plating film.

[Problem to be solved by the invention]

In the lead frame for semiconductor devices as described above,
Due to the heat stress received during the assembly process after chip bonding, an oxide film is formed on the copper surface, making wire bonding impossible.Also, the copper oxide film has weak adhesion to the copper base material, so There was a problem in that a peeling phenomenon occurred between the copper oxide films, reducing the reliability of the semiconductor device.

In addition, as a method for suppressing the formation of a copper oxide film, there is a method of forming a silver film on the copper surface as shown in JP-A No. 62-163353, but silver has a weak adhesion to resin and the resin When used, chip bonding cannot be performed, and the adhesion between the lead frame and the resin is weak in the resin sealing process, resulting in lower reliability of the semiconductor device.

This invention was made in order to solve the above-mentioned problems, and it is possible to suppress the formation of an oxide film on the copper surface, and to obtain a highly reliable semiconductor device with high adhesion to resin. The purpose of the present invention is to provide a lead frame for semiconductor devices.

[Means to solve the problem]

The lead frame for a semiconductor device according to the present invention is a lead frame made of copper or a copper alloy, or a lead frame whose surface is plated with copper, and includes at least a semiconductor device portion on which a semiconductor element is mounted, and a lead frame that includes a semiconductor device part on which a semiconductor element is mounted, and a lead frame that includes a semiconductor element. In a product in which a plurality of leads arranged at predetermined intervals around a mounting part are integrally connected to a lead frame frame, a thin silver film is formed on the surface of the lead frame and heated. It is characterized by forming a mutual diffusion layer of copper and silver.

[Effect]

In this invention, the formation of a copper oxide film is suppressed by forming a silver film on the copper surface, and by providing a mutual diffusion layer of copper and silver by heating, it is possible to prevent the formation of a copper oxide film by forming a silver film on the copper surface. High adhesion can be obtained.

〔Example〕 ' An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional flow diagram showing the manufacturing process of a semiconductor lead frame according to an embodiment of the present invention.

In the lead frame for a semiconductor device according to this embodiment, a copper plating film 2 is first formed on the surface of a lead frame material 1 (FIG. 1a) made of a copper alloy (11 Mb>, and then 0.1 μm from above). The following silver film 3 is formed (FIG. 1c), and then a mutual diffusion layer 4 of copper and silver is formed by heating (FIG. 1d).

Figure 2 also shows a lead frame with a mutual diffusion layer of copper and silver on the surface of the lead frame according to this embodiment, a lead frame with only copper plating without forming a silver film according to the conventional technology, and a lead frame with a silver film on the copper surface. FIG. 3 is a diagram comparing the adhesion strength between resin and a lead frame that has only been used.

In addition, in FIG. 2, the adhesion strength of the lead frame provided with the mutual diffusion layer of copper and silver obtained in this example is 1.
The percentage is shown when it is set to 00.

That is, from FIG. 2, it can be seen that by providing a mutual diffusion layer of copper and silver on the surface of the lead frame, it is difficult to form a copper oxide film and the adhesion to the resin is strong.

〔Effect of the invention〕

As described above, according to the present invention, by providing a mutual diffusion layer of copper and silver on the surface of the lead frame, a copper oxide film is prevented from forming, and the adhesion strength with the resin is increased, resulting in high reliability. This has the effect of providing a resin-sealed semiconductor device.

[Brief explanation of the drawing]

FIG. 1 is a schematic flow sectional view showing the manufacturing process of a lead frame for a semiconductor device according to an embodiment of the present invention, and FIG. 2 is a comparison showing the suppression of oxide film formation and the adhesion strength with resin of the lead frame of the present invention. 3 are plan views of a lead frame for a semiconductor device. In the figure, 1 is the lead frame material, 2 is the copper plating film, and 3 is the lead frame material.
4 is a silver film, 4 is a copper and silver interdiffusion layer, 5 is a lead frame frame, 6 is a semiconductor element mounting part, 7 is a lead, 8 is an internal lead, 9 is an external lead, 10 is a tie bar, 11 is a semiconductor seal The stopper resin area is shown.

Claims (1)

[Claims] A lead frame made of copper or a copper alloy, or a lead frame whose surface is plated with copper, and includes at least a semiconductor element mounting part on which a semiconductor element is mounted, and a predetermined area around the semiconductor element mounting part. In a lead frame for a semiconductor device in which a plurality of leads disposed at intervals are integrally connected to a lead frame frame, a thin silver film is formed on the surface of the lead frame and then heated to form a bond between copper and silver. A lead frame for a semiconductor device characterized by forming a diffusion layer.