| 摘要 |
PURPOSE:To prevent wire disconnection and to form the alpha rays shielding film which can be sealed with resin by providing the dam around the alpha ray shielding film forming region so that the bonding resin for alpha ray shielding film does not flow into a bonding pad and by forming the alpha ray shielding resin with bonding method. CONSTITUTION:The varnish of polyimide precursor is coated on the entire part of a silicon wafer already forming thereon elements and then a negative photo resist is coated thereon. It is then prebaked and is subjected to irradiation of ultra-violet ray using a photo mask and then the photo resist is developed. After the polyimide is etched using hydrazine hydra, the photo resist is separated in order to form a polyimide dam. A chip is cut out from the wafer and it is fixed to a lead frame and is then subjected to wire bonding. The combined N-methyl pyrolidone solution of the poly-imide precursor is dropped into the dam and the ray shielding film is formed by the curing for 30min at each temperature of 150 deg.C, 250 deg.C and 350 deg.C. Thereafter, it is sealed by resin 8. Since the bonding wire 2 is not covered with the alpha ray shielding film 33, it did not show any disconnection. |
