INSULATION MATERIAL FOR CIRCUIT BOARD, THE CIRCUIT BOARD, AND METHOD OF MANUFACTURING THE BOARD

摘要

PROBLEM TO BE SOLVED: To make dehalogenation and flame-retarding of a circuit board compatible with each other, and in addition, to eliminate nonconformities, including the characteristic deterioration of the circuit board caused by a non-halogen flame retardant. SOLUTION: The characteristics deterioration of the circuit board caused by dehalogenation is improved by means of the constitution of the board. The non-halogen circuit board has the feature such that the content of the non- halogen flame retardant becomes smaller, going toward the inside of each insulating layer from the surface of the layer or the ratio of the Young's modulus of each insulation layer at 125 deg.C to that of the layer at 25 deg.C is adjusted to >=0.8. In addition, the content of the non-halogen flame retardant in the outermost insulation layer is made smaller than those of the retardant in the inner insulation layer or the Young's modulus of the outermost insulation layer at 125 deg.C is made larger than those of the inner insulation layers at 125 deg.C.