Bonding wire for semiconductor

Abstract

Disclosed is a bonding wire for semiconductor, which ensures good wedge bonding even of palladium-plated lead frames and has excellent oxidation resistance, and in which copper or a copper alloy is used as a core wire. The bonding wire is characterized by comprising a core wire that comprises copper or a copper alloy, a coating layer that is arranged on the surface of the core wire, has a thickness of 10 to 200 nm and contains palladium, and an alloy layer that is arranged on the surface of the coating layer, has a thickness of 1 to 80 nm and contains a noble metal and palladium, wherein the noble metal is silver or gold, and the noble metal is contained in the alloy layer at a concentration of 10 to 75 vol% inclusive.

Description

technical field [0001] The present invention relates to a bonding wire for a semiconductor used for bonding an electrode on a semiconductor element and an external connection terminal. Background technique [0002] At present, as a semiconductor bonding wire (hereinafter referred to as a bonding wire) for connecting an electrode on a semiconductor element and an external terminal, a wire diameter of about 20 to 50 μm and a material of high-purity 4N (4-Nine, with a purity of 20 to 50 μm) are mainly used 99.99 mass % or more) gold (Au) bonding wire (gold bonding wire). In order to bond a gold bonding wire to an electrode on a silicon chip as a semiconductor element, ball bonding by ultrasonic and thermocompression bonding is generally performed. That is, the method is as follows: using a general-purpose bonding device, the above-mentioned gold bonding wire is passed to the inside of a jig called a capillary, the tip of the wire is heated and melted by arc heat input, and a s...

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Problems solved by technology

Although the above-mentioned documents do not show the superiority of palladium, since the melting point of palladium is higher than that of silver (melting point 1554°C), and the specific heat of palladium is higher than that of gold (244J / kg·K), it is considered that if palladium is coated, the following problems can be solved. Problem: Like the above-mentioned silver and gold, the coating layer is melted before the copper wire is melted to form the spherical portion, and the spherical spherical portion cannot be formed.

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