What are the problems with the LED package copper wire process?
In the LED package, the copper wire process has been researched and developed by LED lamp manufacturers because of its cost reduction, and has been adopted by many manufacturers. However, in practical applications, the copper wire process has many problems. Here are some common questions that I hope will inspire you.
1) The copper wire is oxidized, causing the gold ball to deform and affecting the product qualification rate.
2) The first solder joint aluminum layer is damaged, especially for the thickness of the aluminum layer of <1um;
3) The second solder joint defect is mainly due to the fact that the copper wire is not easily combined with the bracket, resulting in cracking or damage of the crescent, resulting in poor soldering of the second soldering, and there is a reliability risk during the use of the customer;
4) For many brackets, the power of the second solder joint, the USG (ultrasonic) friction and pressure parameters need to be optimized, and the excellent rate is not easy to be high;
5) It is difficult to unpack when performing failure analysis;
6) Equipment MTBA (hourly output rate) will be lower than gold line process, affecting production capacity;
7) The training period for operators and technicians is relatively long, and the skills and quality requirements for employees are relatively high compared to gold wire welding, which has an initial impact on production capacity;
8) It is prone to material confusion. If there is gold wire and copper wire production at the same time, the production control must pay attention to the storage life and distinguish the material list. If the wrong or oxidized line can only be scrapped, the miss operation warning will occur frequently, and the bad risk will increase. Big;
9) The cost of consumables increases, and the life of the copper wire is usually reduced by half or more compared to the gold wire. At the same time, the complexity of production control and the cost of porcelain mouth consumption are increased;
10) Compared with gold wire welding, in addition to the fire-fighting rod (EFO), there is a forming gas (synthetic gas) protective gas conveying pipe, and the positions of the two must be aligned. This directly affects yield. Precise control of the flow of protective gas, increased cost, and low defect rate;
11) Al Splash. It is usually easy to appear in a wafer with a thick aluminum layer. It is not easy to identify the impact, but be careful not to cause a short circuit. It is easy to crush the PAD or a solder ball. Cause low test or customer complaints;
12) Oxidation occurs after the completion of the line, there is no standard judgment risk, which may cause poor contact and increase the defect rate;
13) Need to re-optimize the wire pull, ball shear test standard and SPC control line, the current gold wire use standard may not be fully applicable to the copper wire process;
14) There are some restrictions on the underlying structure of the first pad, such as Low-K die electric, with via holes, and circuits with underlying layers, all need to be carefully evaluated. The existing wafer bonding Pad design rule for copper The line process needs to be optimized in depth. But today's packaging plants that use copper wire do not seem to affect the development of the chip;
15) From the customer's resistance, the copper wire process is more difficult for customers who have higher reliability requirements, and even more, they lose customer trust;
16) Copper wire process may have reliability problems for using non-green plastic sealant (containing halogen elements)
17) If there is fluorine or other impurities on the pad, the reliability of the copper wire will be reduced.
18) Evaluations like Die to Die bonding and Reverse bonding are not yet complete.
Stainless Profile Roll Forming Line
Metal Rolling,Profile Roll Forming Machine,Stainless Profile Roll Forming Line,Stainless Profile Roll Forming Machine
Xinxiang Tianfeng Machinery Manufacture Co., Ltd. , https://www.tfrollforming.com