| Bond wire is an indispensable basic material in chip packaging.The rapid development of packaging technology has increased the requirements for bonding wire specifications.Gold bonding wire is the best choice in high-end packaging,but its price is higher.Copper bond wires have excellent electrical,thermal and mechanical properties and are inexpensive,making them an alternative to gold bond wires.Copper bond wires are susceptible to oxidation during packaging and service,limiting their use in semiconductor packaging.The preparation of copper-based composite bonding wires by alloying and surface modification is a feasible solution to the problem of easy oxidation of copper bonding wires.Alloying requires a large amount of oxidation-resistant metal smelting,which significantly increases the cost of copper-based bonding wires.Surface anti-oxidation metal-modified copper-based composite bonding wires are an effective means.Silver has excellent oxidation resistance,and surface-modified copper-silver composite bond wire is a feasible method.At present,the copper-based composite bonding wire is prepared by continuous electroplating in the industry,and the equipment is precisely controlled,which significantly increases the cost of preparing the copper-based composite bonding wire.In this paper,the copper-silver composite bond wire is prepared by electroplating on a thick copper rod and continuous cold drawing and annealing,which can effectively reduce the cost of preparing the bonding wire.However,the formation mechanism of copper-based silver layer and the coordination deformation mechanism of copper-based silver coating determine the properties of copper-silver composite bond wires.Therefore,in this paper,the copper plate is used to study the law of electroplating silver and its coordinated deformation behavior with copper.This paper mainly explores the preparation process of the coating and the influence of its structure on the properties of the coating.Firstly,the plating law of the plating layer is firstly studied on the copper plate,and then the silver-plated copper plate is subjected to a rolling experiment,and the rolled sample is analyzed and tested to obtain the optimum process parameters,and then electroplated on the copper rod,followed by drawing,and then obtained.Finished bond wire.Since the deformed porosity and structure of the finished wire are difficult to characterize,we use the rolling method to simulate the deformation behavior during the drawing process,and the previously prepared copper plate is rolled,and then the properties of the coating are characterized.test.The morphology of the coating was mainly observed by SEM.The porosity of the coating was characterized by electrochemical test.The orientation structure of the coating was calculated by XRD,and the deposition rate and current efficiency were characterized by weighing calculation.The results show that the coating prepared at current density of 0.5~0.8 A/dm2 has a flat and dense surface.The too small current density will make the nucleation rate much larger than the crystal growth rate,and it will not form a dense coating.The current density causes the coating to burn.When the plating time is short,the grain orientation of the coating is related to the plating time,but when the plating time is increased to 60 min,the(220)crystal plane begins to dominate,and the preferred orientation is(220).Properly increasing the plating temperature will increase the deposition rate and current efficiency of the coating,but will result in a rough surface.The surface of the bond wire surface prepared by the new method substantially maintains a good surface after a hundred passes of the drawing process,but the surface agglomerates after annealing.The sample is subjected to a phase annealing test.As the annealing temperature increases,the fracture strength of the material decreases,and the elongation has an increasing trend,but the variation range is small,which is basically similar to that of the pure copper wire. |
PDF Full Text Request