PURPOSE: To improve the heat sink property of a hybrid IC by superposing a heat sink sheet on the upper surface of a bondable resin to coat a chip part, hermetically sealing it, thereby improving the moisture preventing effect and preventing the chip part from deteriorating.

CONSTITUTION: A sheetlike bondable resin such as epoxy resin 5 is placed on the top of a chip part 3 which is placed on a ceramic substrate 1, a heat sink sheet 6 made of an aluminum plate is superposed, heated, pressurized to melt the resin 5, solidified and coated like the bondable resin 5a. Thus, air might not be wound, the moisture preventing effect is improved, and heating temperature can be reduced. Accordingly, the chip part may not be deteriorated. The sheet 6 is integrated to improve the heat sink property of a hybrid IC.