屏蔽板补偿作用改进引线框架镀层厚度均匀性

Improving the Coating Thickness Uniformity of Lead Frame Plating by Using Shielding Board Compensation Effect Properly

基于统计学理论建立了镀层厚度均匀性评估的方法并分析了电镀工艺中对其产生影响的因素。最终发现,通过调整电镀槽中屏蔽板的上下位置,使引线框架形成上薄下厚和上厚下薄的两种分布的镀层厚度,这两种镀层厚度叠加在一起改善镀层整体的厚度分布,从而提高了新型引线框架表面电镀层厚度的均匀性,同时降低了镀层厚度超出规格限的风险。

A new method was set up to evaluate the coating thickness uniformity of lead frame plating based on statistics theory. Factors which could affect the coating thickness uniformity were screened out with Fish-Bone Chart. And finally found out that shield board height was the key factor. When the shield board height was adjusted in different location, there were two types of thickness distribution. One was thinner on top and thicker on bottom of the lead frame, the other one was thicker on top and thinner on bottom. Superposition of the two types of coating thickness could improve overall coating thickness, thereby coating thickness uniformity of the new lead frame was improved, while the risk of coating thickness exceeding specification limit was reduced.