| 摘要 |
PURPOSE:To prevent the malfunction of semiconductor device by a method wherein a ceramic package covering the active region of semiconductor is exposed in an atmosphere of F to reduce W and Th content. CONSTITUTION:When an Al2O3 ceramic package cap 10 is exposed in F gas, U and Th existed in the neighborhood of surface is evaporated and removed by the reaction of U+F UF. U and Th existed in the surface layer of about 20mum is removed by this treatment, and the quantity of alpha rays can be reduced to about 1/ 100. Then the cap 10 is assembled with a base 11 to constitute a package, and a semiconductor chip 15 is enclosed in it and is sealed with glass 17. By this constitution, the malfunction of active region is prevented. alpha Rays are yet radiated from the base 11, but are attenuated during the passing through the chip body, and the malfunction of active region in the surface does not take place. |
