| 摘要 |
PROBLEM TO BE SOLVED: To enhance insulation characteristics of a circuit board by forming a layer of substrate of an organic insulating material having a 10 wt.% reduction temperature based on TGA within a specified range and a permittivity of a specified value or less. SOLUTION: The circuit board has a layer of substrate composed of an organic insulating material having a 10 wt.% reduction temperature based on TGA (thermal gravimetric analysis) in the range of 140-300 deg.C and a permittivity of 3.5 or less. The organic insulating material composing the substrate contains an organic polymer which forms a continuous phase in the organic insulating material. The organic polymer forming a continuous phase in the organic insulating material is dispersed with cross-linking resin particles having means grain size of 0.03-10 and permeability of 4 or below. Consequently, the insulation characteristics can be enhanced and the circuit board can be used in high frequency region while enhancing reliability by suppressing crosstalk during use after mounted with a semiconductor element and suppressing generation of heat. |
