| 摘要 |
<p>PURPOSE:To improve the yield of package, even for a lead having fine pitch, by providing a clad layer for making uniform the amount of solder at the tip of the lead in a gull wing type semiconductor device. CONSTITUTION:A semiconductor device 1 comprises an insulating resin package 2 and a plurality of leads 3 of metallic body projecting in parallel from four sides of the package 2. The lead 3 is provided with a solder clad layer 8 in the mounting region on the rear surface at the outer mounting end 4. The semiconductor device 1 is mounted on a wiring substrate 15 such that the mounting end 4 of each lead 3 is lapped over a footprint 17 arranged on the surface of the wiring substrate 15. Each mounting end 4 section is then subjected to partial heating through irradiation of infrared beam and the like. Consequently, the clad layer 8 is melted and spread over the footprint 17 on the wiring substrate 15. Solder 19 is set upon stoppage of heating and the mounting end 4 is secured to the footprint 17. By such arrangement, appropriate amount of solder can be provided and leakage of solder or formation of solderbridge can be prevented.</p> |
