JPS6474748A - Lead frame - Google Patents

Abstract

PURPOSE:To prevent the intrusion of water content and moreover, to prevent the corrosion of a pad by a method wherein a lead frame is constituted into a structure, wherein the width of a tab is partially made narrow or left and right leads are by-passed and arranged at a place, from where the tab itself is removed, and a roughly rectangular insulator is mounted on a plane including the by-pass lead parts. CONSTITUTION:Both sides of the longer sides of a rectangularly formed tab 1, which is connected to frames 5 through suspension leads 2, are partially recessed and the width of the tab becomes narrower. By-pass parts 3a of leads 3, which are coupled with tie bars 4, are arranged at the recessed parts and the points of the leads 3 come out on the outside of the tab 1. Moreover, such a rectangular insulating film 7 as a capton film is adhered on a plane including the tab 1 and the parts 3a for keeping a state insulated from the leads 3. There by, the film can be formed into the almost same form as a normal form formed of the metallic material of the tab 1. That is, a supporting region for mounting an IC chip is secured. Moreover, the parts 3a are subjected to depressing processing and the intrusion of water content to follow a path of the leads 3, the film 7 and the chip is delayed.