| 摘要 |
PROBLEM TO BE SOLVED: To avoid cracking solder balls due to a thermal stress of a thermal hysteresis in a circuit structure by providing members made of a material having a higher tensile strength than that of solder on a plurality of electrodes. SOLUTION: Holes 2a are bored by laser-machining at circuit wiring electrode forming positions of a film substrate 2 and masked with resin, a Cu foil at the holes is etched to form a circuit pattern, the resist masking is peeled off, and the Cu foil is plated, an insulation layer 6 is formed to finish a flexible circuit board. Semiconductor elements 1 are mounted on the circuit board 2, and bonded and sealed with a resin material 10, and filling members 12 are formed of a material having a higher tensile strength than that of solder balls 14 on electrodes 4A, 4B of a wiring 4 on the circuit board 2. |
