MULTILAYER CIRCUIT BOARD

摘要

PURPOSE: To reduce the coefficient of linear expansion of a multilayer circuit board which has conductive circuits in a top layer and inner layer and insulating layers which are respectively put between circuit layers and composed of glass woven fabrics impregnated with an epoxy resin so as to improve the surface mounting reliability of the circuit board and maintain the moisture-resistant migration characteristics of the circuit board at an excellent state. CONSTITUTION: The resin content of a multilayer circuit board is adjusted to 30-45wt.% and the modulus of elasticity of the resin is limited to <=200kg/mm<2> . It is preferable to use a basket-woven glass fabric as the glass woven fabric put between circuit layers in the circuit board. In addition, it is preferable to adjust the glass-transition temperature of the circuit board to >=140 deg.C and thickness of the copper foil constituting the inner-layer circuit of the circuit board to <35μm.