| 摘要 |
PROBLEM TO BE SOLVED: To prevent plating silver from leaking along the side surfaces of inner leads when silver plating is applied in the manufacturing process of a lead frame from leaking out of a mold area by a method wherein plating silver leaking preventive dam bars are formed between the inner leads and the mold area. SOLUTION: In a lead frame whose inner lead tips are plated 7 with silver, in addition to dam bars 5 which prevent sealing resin from leaking out at the time of resin sealing, additional dam bars 9 made of metallic material are formed in the manufacturing process of the lead frame and cut off after silver plating. Further, dam bars made of UV-curing resin are formed on the middle parts of the inner leads 4. With this constitution, a desilvering process after resin sealing can be eliminated and, further, solder plating swellings of outer leads and short-circuiting between outer leads which are caused by the leaking silver can be avoided. |
