JPH0211015B2 - - Google Patents

Description

[Detailed description of the invention]

This invention is suitable for use in wire bonding performed during the manufacture of semiconductor devices.
It concerns Au or Au alloy thin wire. In general, semiconductor devices include transistors and
IC and even LSI are well known, but for example, IC
Semiconductor devices such as (a) Au, Cu alloy plate or strip on one side;
A lead material made of a plating layer of Ag, Ni, or their alloys is prepared, and (b) the lead material is press punched to form a lead frame that matches the shape of the semiconductor device to be manufactured. (c) A semiconductor element made of high-purity Si or Ge is thermocompression bonded to a predetermined location of the lead frame through the plating layer, and (d) Au or Au alloy fine wire is attached to the lead frame and the semiconductor element. (e) Pack the semiconductor element, the Au or Au alloy fine wire, and the lead frame where the semiconductor element is attached with plastic. , (f) Finally, the interconnected portions of the lead frame are cut out to form a lead material. The lead frame is manufactured by the main steps (a) to (f) above. In this way, when manufacturing a semiconductor device, wire bonding is performed using Au or Au alloy thin wire in the step (d) above, and conventionally the bonding wire is as shown in Figure 1 of the attached drawings. , wound in a single layer on an aluminum spool
Au or Au alloy thin wires have been used, and connections between semiconductor elements and lead frames have been made using manual or automatic bonding machines. However, in recent years, efforts have been made to improve bonding machines and production techniques in order to increase productivity, resulting in faster bonding speeds and a demand for longer bonding lines. Therefore, with the conventional single-layer winding, the winding amount is limited to 100 to 200 m at most.In order to meet the above requirements, recently, cross winding as shown in Figure 2 of the attached drawings has been developed. Multi-layer windings have been used, and the winding length has increased from 500 to 1000 m.
However, when such multilayer windings are used, the following problems occur. In other words, in the case of single-layer winding in Figure 1, the bonding wire has no points where the wires touch each other, so the Au wire will not get caught and break when the wire is taken out, but in the case of multi-layer winding, As is clear from Figure 2, the Au wire to be taken out is in the lower layer.
Since it is rubbed on the Au wire and taken out, the taken out Au wire is likely to be bent.
This fold will be bonded as is, so
The bonding group is deformed, causing sagging and bending, which causes shortening and product defects. Therefore, from the above viewpoint, the present inventors
As a result of extensive research in order to eliminate the above-mentioned folds in multilayer windings for wire bonding, we have developed a coating treatment with polyoxyethylene alkylamine, an organic compound-based antistatic agent, on the surface of Au or Au alloy thin wire. If the average thickness of the film is 0.5 μm to 50 Å, it will be removed.
They found that the Au or Au alloy fine wires do not break, and bonding can be performed at high speed and with a normal loop shape. The present invention has been made based on the above knowledge, and includes Au or Au for wire bonding of semiconductor devices, which is wound in multiple layers on a spool.
It is characterized in that the surface of the thin alloy wire is coated with a film of polyoxyethylene alkylamine to an average thickness of 0.5 μm to 50 Å. The reason why the average film thickness of the coating was limited as described above will be described below. As mentioned above, the thermocompression bonding method and the ultrasonic thermocompression bonding method are normally used for wire bonding, but if the coating film is too thick, bonding defects will occur and the bonded part will peel off, while on the other hand, the coating film is too thin. Then, the effect of the coating appears when the average thickness of the coating is reduced from the point where the coating has no effect and the breakage described above occurs and the bonding group deforms, leading to shoots.
The range was from 50 Å to 0.5 μm without peeling. Further, as a solvent for forming a coating solution of polyoxyethylene alkylamine, a well-known volatile solvent that can dissolve polyoxyethylene alkylamine, such as chlorofluorocarbon or acetone, can be used. By applying a coating solution in which oxyethylene alkylamine is dissolved onto Au or Au alloy thin wire and then evaporating the solvent, an extremely thin coating film can be formed on the surface of Au or Au alloy thin wire. Next, the Au thin wire of the present invention will be specifically explained using examples. Example Aqueous solutions of polyoxyethylene alkylamine with various concentrations shown in Table 1 were prepared using
Coated Au wires 1 to 6 of the present invention formed by continuously coating the surface of the Au wire and drying the coated Au wires 1 to 6 of the present invention,
A bonding test was conducted by winding 1,000 m of cross multilayer winding on an aluminum spool and investigating the number of deformed loops that occurred in this winding after 50,000 high-speed bonding cycles.

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Claims (1)

[Claims] 1 The surface of gold or gold alloy thin wire is coated with polyoxyethylene alkylamine, an organic compound-based antistatic agent, with an average film thickness of 0.5 μm to 50 Å.
1. A thin gold or gold alloy wire for wire bonding of semiconductor devices, which is wound in multiple layers on a spool and is characterized by having a polyoxyethylene alkylamine film formed thereon.