The difference between gold wire and alloy wire for SMD LED
In LED packaging, the alloy wire process has been studied by LED packaging factories for its cost reduction and has been adopted by some manufacturers. However, in actual applications, compared to gold wire welding, the alloy wire process has many problems. Alloy wires are divided into high-gold alloy wires and high-silver alloy wires. The cost of high-gold alloy wires with a gold content of more than 60% does not decrease significantly. Therefore, most packaging factories that use alloy wires use high-silver alloy wires. Some common questions are listed below, I hope to inspire everyone.
(1) It is easy to oxidize, causing deformation of the golden ball and affecting the product qualification rate;
(2) Defects of the second solder joints are mainly caused by cracking or damage of the crescents caused by the alloy wire not being easily combined with the bracket, leading to poor welding of the second welding, and there is a reliability risk during the customer's use;
(3) For different types of brackets, the power of the second solder joint, USG (ultrasonic) friction and pressure and other parameters need to be optimized, and the good rate is not easy to increase;
(4) It is difficult to open the package during failure analysis;
(5) The MTBA (hourly output rate) of the equipment will be lower than that of the gold wire process, which will affect the production capacity;
(6) The training period for operators and technicians is relatively long, and the skill and quality requirements of employees are higher than that of gold wire welding, which will definitely affect the production capacity at the beginning;
(7) The cost of consumables increases, and the life of the porcelain nozzle of the alloy wire is usually reduced by 1/3 or more than that of the gold wire. At the same time, it increases the complexity of production control and the cost of porcelain nozzle consumption;
(8) Oxidation occurs after the line is placed, and there is no standard to judge the risk, which is likely to cause poor contact and increase the defect rate;
(9) It is necessary to re-optimize the standards for Wire Pull and ball shear testing and the SPC control line. The current standards for use of gold wires may not be fully applicable to the alloy wire process;
(10) Resistance from customers, the alloy wire process is still more difficult to accept for some customers with higher reliability requirements, and even worse, they lose their trust;
(11) The alloy wire process may have reliability problems for the use of non-green plastic sealants (containing halogen elements)
