防止4J29引线框架电镀层开裂的新工艺  

A New Technology for Preventing Plating Cracks of 4J29 Lead Frame

作　　者：汪烈焰[1] 朱超锋[1] 林楚宏 蔡阳伦 

机构地区：[1]北京理工大学珠海学院,广东珠海519000

出　　处：《表面技术》2017年第6期282-286,共5页Surface Technology

摘　　要：目的防止4J29细引线框架在电镀Ni/Au或Ni/Pd/Au过程中镀件细线断裂及镀层局部出现开裂。方法采用对比的方法,通过200倍放大镜仔细观察电镀工艺改变或调整前后细引线镀层外观质量,再经过单片弯折实验,观察电镀后细线有无断裂或开裂现象,对有断裂或开裂等缺陷的产品进行统计,计算次品率。结果电镀前对工件进行热处理,基本可以消除工件电镀后框架细线断裂的问题。通过改变电镀镍工作液组成及工艺条件,能有效解决镀件局部出现开裂的问题。电镀前,原始片热处理的工况为:温度420~450℃,保温时间120 min,采用自然冷却的方式冷却到室温。电镀镍的工艺规范为:氨基磺酸镍250~350 g/L,硼酸25~35 g/L,润湿剂(K12)0.01 g/L,糖精0.3~0.4 g/L,pH值3~5,温度50~60℃,电流密度3.0~5.0 A/dm^2。结论开发了一种防止4J29引线框架电镀后细线断裂及电镀层开裂的新的电镀工艺方法。经过企业实际使用,并抽样进行每单片10次90°弯折实验,新的电镀工艺生产的产品,其次品率稳定控制在2%以下,其他性能检测也符合企业产品质量要求。The work aims to prevent 4J29 fine wire from breaking and plating local cracking during Ni/Au or Ni/Pd/Au plating. By comparison and contrast, appearance quality of the fine-wire plating was observed using a 200 x magnifying glass before and after the plating process was changed or adjusted, and then bending test was performed to observe whether the elec- troplated fine-wire was subject to breaking or cracking, products subject to such defects were counted, and defect rate was cal- culated. Heat treatment of the workpiece before electroplating could eliminate crack of the thin frame after the workpiece was electroplated. By changing composition and process conditions of electronickelling working solution, local cracking of the plated workpiece could be effectively resolved. Operating conditions of heat treatment were as follows： temperature of 420-450 ~C, holding time of 120 min, cooling mode of natural cooling to room temperature; electronickelling process specifica- tion was as follows： 250-350 g/L of nickel sulfamate, 25-35 g/L of boric acid, 0.01 g/L of wetting agent （KI2）, saccharin of 0.3-0.4 g/L, pH of 3-5, temperature of 50-60 ℃, current density of 3.0-5.0 A/din2. A new electroplating process is developed to prevent fine wires from breaking and the plating from cracking after 4J29 lead frame is electroplated. After actual use by en- terprises, and sampling each uniwaver for ten 90° bending tests, defective rate of the products produced in new electroplating process falls within 2% and other performance tests meet enterprise product quality requirements as well.

关 键 词：4J29合金 引线框架 电子封装 热处理 电镀 电镀镍 电镀金 

分 类 号：TQ153[化学工程—电化学工业]