Ultra-thin copper alloy bonding wire for microelectronic packaging and preparing method of ultra-thin copper alloy bonding wire

Abstract

An ultra-thin copper alloy bonding wire for microelectronic packaging is characterized by being prepared from 10-50 wt.ppm of Ti, 10-50 wt.ppm of Li, 10-50 wt.ppm of Zr, 10-50 wt.ppm of Fe, 10-50 wt.ppm of Ag, 10-50 wt.ppm of B, 10-50 wt.ppm of a rare earth element and the balance copper and inevitable impurities, wherein the content of O and S in the impurities accounts for 5 wt.ppm or less in the whole copper alloy bonding wire, and the rare earth element is one of Eu, Y and Dy or a combination of Eu, Y and Dy. The invention further provides a preparing method of the ultra-thin copper alloy bonding wire for microelectronic packaging. The copper alloy bonding wire has the good oxidation resistance, good electric and heat conductivity, good weldability, large single wire length and other good performance, and the preparing method of the copper alloy bonding wire is easy and convenient to implement.

Description

technical field [0001] The invention relates to a bonding wire for packaging, in particular to an ultrafine copper alloy bonding wire for microelectronic packaging and a preparation method thereof. Background technique [0002] Bonding wire is used as an electrical connection wire to connect the electrodes on the semiconductor element and the external terminals, mainly 4N series (purity >99.99% (weight)) gold and other trace element alloys with a wire diameter of about 20-50 μm However, because gold is expensive and the price has continued to rise in recent years, finding materials to replace gold wires has always been a research hotspot in the field of electronic packaging. [0003] Copper is considered to be a suitable bonding wire material to replace gold due to its excellent thermal and electrical properties and lower price. However, copper wire has a series of disadvantages compared with gold wire: the surface of the wire is easily oxidized, resulting in reduced bond...

AI Technical Summary

Problems solved by technology

[0003] Copper is considered to be a suitable bonding wire material to replace gold due to its excellent thermal and electrical properties and lower price. However, copper wire has a series of disadvantages compared with gold wire: the surface of the wire is easily oxidized, resulting in reduced bonding strength, It is easy to cause corrosion on the surface of the wire during resin encapsulation, and the high hardness is easy to cause damage to the substrate during wiring, etc.

The copper wire with this alloy composition not only overcomes the problems of high hardness and poor welding performance of pure copper wire, but also has high conductivity and elongation, good weldability and low cost, but there are still two problems: (1) The content of O and S is not controlled. If the content of O is too high, the plasticity and toughness of the copper wire will be deteriorated, and the added elements will be oxidized so that the alloying effect is not obvious; (2) The casting process adopts the method of casting, ingot casting There is casting stress inside, and drawing is done directly without relevant heat treatment, resulting in uneven mechanical properties and component distribution of the product, which will affect the quality and life of the product

However, this process has the following problems: (1) The external friction between the metal and the tool in the continuous extrusion process is large, the extrusion tool wears quickly, the service life is short, the cost is high, and the extrusion speed is slow and the production efficiency is low; (2 ) does not add grain refiner, it is easy to cause abnormal grain growth in the intermediate annealing process, resulting in uneven material structure

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