MULTILAYER PRINTED CIRCUIT BOARD AND METHOD FOR ITS MANUFACTURING Russian patent published in 1999 - IPC

FIELD: radio engineering. SUBSTANCE: device has upper current-conducting layer, lower current-conducting layer and tar insulation layer, which provides electric insulation of both current-conducting layers. Tar insulation layer is designed as composite layer which consists of lower insulation layer of heat-proof acid- or solvent-proof tar, and upper adhesion layer for non-electrolytic coating of heat-proof layer. If necessary, recesses provided between circuits of lower layer conductor are filled with tar in order to level its surface in same plane as surface of current-conducting circuit. EFFECT: printed circuit board is resistant to heat and cold impact without unevenness of its surface and decreased resistance to layer peeling even for thin insulation layer. 19 cl, 19 dwg