Circuit board and method for its production

Abstract

Abstract The circuit board comprises a substrate consisting of an electrically insulating material. On its top, the substrate has an inwardly tapering depression (10') and a recess (10''') which extends from the base (10'') of the depression into the substrate. Arranged in the recess is a semiconductor element (A) which is electrically connected to leads (20) on the top of the substrate. The leads extend over the inclined wall of the depression to the edge of the recess. The semiconductor element is surrounded by synthetic resin (P) which fills the recess and the depression. The free surface of the plastic is coplanar with the top of the substrate. The lead pattern (20) is produced with the aid of a photomask and of a photoresist layer which is applied onto the substrate. The photomask is in this case arranged at a distance from the substrate and is imaged on the photoresist layer of the substrate with the aid of an objective lens which is arranged between the photomask and the substrate. If the inclination and depth of the depression in the substrate are not too large, the lead pattern can be printed on the substrate with the aid of an elastic rubber roller. <IMAGE>

Inventors

• 👤 Masahiro Fujimori
• 👤 Sanenobu Sonoda

Bibliographic Details