Method for preparing silver-based bonding wire

Abstract

The present invention discloses a method for preparing a silver-based bonding wire. Firstly, 2.0% to 4.0% of Pd, 3.0% to 5.0% of Ce and 4.0% to 6.0% of Cu are added into Ag whose purity is higher than 99.999% to be mixed to be an alloy substrate, and the silver-based bonding wire is prepared through the smelting, drawing, cleaning, annealing, winding, packaging and other steps of the alloy substrate. The nitrogen protection is not needed in the melting process, and the adding of a high temperature molecular sieve and repeated vacuum pumping are used to carry out oxide removing. At the same time the alloy metal melted liquid is completely and uniformly melted through repeated melting, the prepared silver-based bonding wire has the advantages of good consistency, stable performance, and high extension rate and tensile strength, the reliability and stability of welding quality and a device are ensured, the whole production process is smooth, and the production efficiency is improved. At the same time, the silver-based bonding wire has the advantages of good oxidation resistance, good electrical conductivity and moderate cost and can be widely applied to the field of electronic packaging of an IC, an LED and the like.

Description

technical field [0001] The invention relates to the technical field of bonding wire processing, in particular to a preparation method of silver-based bonding wire. Background technique [0002] As a semiconductor device, bonding wire is one of the important structural materials in the packaging industry of large-scale integrated circuits. [0003] It plays the role of connecting the silicon chip electrode and the external lead-out terminal of the lead frame, and transmits the electrical signal of the chip and dissipates the heat generated in the chip. It is the key material of integrated circuit packaging. The quality of the bonding wire material directly affects the welding quality. Thus, the reliability and stability of the device are greatly affected. [0004] Among the transition group metal elements in the periodic table of elements, silver, copper, gold and aluminum have high electrical conductivity. Among them, the bonding gold wire has excellent thermal conductivity...

AI Technical Summary

Problems solved by technology

[0004] Among the transition group metal elements in the periodic table of elements, silver, copper, gold and aluminum have high electrical conductivity. Among them, the bonding gold wire has excellent thermal conductivity, mechanical properties and chemical stability, and is used in bonding wires. However, it also has its own insurmountable shortcomings: it is expensive, and is greatly affected by the sharp rise in market metal parts, which restricts the control of packaging costs and leads to high prices for end products, which is not conducive to enterprises to improve their competitiveness.

The price advantage of bonding copper wire is obvious, but there are still some disadvantages: for example, the second solder joint caused by the excessive hardness of the copper wire is easy to shrink, causing the interruption of the bonding operation, causing difficulties in the subsequent packaging process, and seriously affecting the production efficiency and yield; The oxidation temperature is low, and the high oxidation property of the bonding copper wire makes the bonding copper wire must be used up in a short time after opening the package, the length of the finished bonding wire is limited, and the storage requires vacuum or protective gas

[0005] Bonding silver wire is cheap, has good conductivity and heat dissipation, and has good reflective properties and does not absorb light. Generally, multi-component doped alloys are added with trace elements to reduce the formation of metal compounds, reduce the degradation of bonding performance, and make the bonding performance as stable as gold wire. , the preparation of silver-based bonding wire is generally carried out according to the process flow of master alloy preparation-continuous casting-drawing-annealing-winding-packaging, but the existing silver-based alloy bonding wire preparation process is to prevent the bonding wire from oxidation Both need to add nitrogen protection during the alloy smelting process, and due to improper control of key factors, it is difficult to achieve complete homogenization of the alloy after fusion. Welding quality reduces the reliability and stability of the device, and also affects the smoothness of the entire bonding wire production, reducing production efficiency

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