SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE:To eliminate the occurrence of erroneous operations in a memory circuit due to alpha rays, by covering a semiconductor substrate with a polyimide resin or a PII resin to a thickness of 10mum or more. CONSTITUTION:alpha particles flying from impurities included in a package material are attenuated and absorbed by a polyimide resin or a polyimide-iso indoloquinazolinedione resin (PII resin) 23. Therefore it is requested that the resin coating film, which is to become the absorbing material is a thick film so as not to transit the alpha particles. It is desirable that the thickness is at least 10mum or more. It is more desirable when the thickness is 30mum or more. The PII resin 23 is applied on a wafer and half cured by heat treatment. A bonding pad part 22 is opened by hot etching using the aqueous solution of hydrazine. The resin is fully cured by heat treatment. Thus the occurrence of erroneous operations in a memory circuit due to alpha rays can be eliminated.