| 摘要 |
PURPOSE:To realize enough imprinting strength with no cleansing treatment on the surface of a molded part before imprinting by a method wherein the sealing with marking ink and consecutive baking treatment are performed before postcuring after epoxy resin molding material is molded with a mold. CONSTITUTION:First, a disc is molded out of epoxy resin molding material, which is widely used for sealing various semiconductors, by transfer molding. Secondly, the surface of the disc is imprinted with marking ink which is generally used for the labeling of various semiconductor element molded parts. Thirdly, the resultant disc is hardened by heating at 150 deg.C for 3hr. Fourthly, the imprinting mark is rubbed with a polyvinylchloride plate by the strength so large as to nearly break the plate in order to find out the number of rubbing required for scraping off some part of the imprinting characters. The imprinting characters withstand more than 30 rubbing strokes, resulting in showing that said imprinting characters have strikingly high imprinting strength.
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