| 摘要 |
PURPOSE:To prevent the hygroscopicity of polyimide even in a thin-film multilayer circuit substrate using polyimide as an inter-layer insulating layer, to improve moisture resistance and to enhance reliability by coating the top face and side face of a polyimide layer with the insulating film of SiO2, Si3N4 or the like. CONSTITUTION:A NiCr-Au thin-film conductor 12 is applied onto an alumina substrate 11, a photosensitive polyimide layer 13 is spin-coated and dried, and contact holes 14 and a specified pattern are formed through a photoetching method, etc. A tantalum resistor 16 and an upper thin-film conductor 15 are applied, and the specified pattern is shaped through the photoetching method, etc. Lastly, an SiO2 layer 17, Si3N4 or the like is shaped to an uppermost section as a passivation film, and the top face and side face of the polyimide layer 13 are also coated with the SiO2 layer 17. Accordingly, a thin-film multilayer circuit substrate having excellent moisture resistance arnd high reliability can be acquired. |
