| 摘要 |
PROBLEM TO BE SOLVED: To maintain the high-speed and high-frequency characteristics of electronic parts to obtain their high-density mountings, in relation to mounting boards, mounting methods and semiconductor devices. SOLUTION: There is formed a circuit board 20 having on its one surface a recessed portion 21B with a single step-surface or a plurality of step-surfaces and having on the respective step-surfaces of the recessed portion 21B and/or on its one surface a single land or a plurality of lands 24 provided oppositely to the electrodes disposed on the circuit-surface of an electronic part mounted on it. Then, joining the electrodes of the electronic part to the opposite lands 24 thereto of the circuit board 20 via bumps 25, an insulation resin is filled subsequently into the gap between the respective step-surfaces of the recessed portion 21B of the circuit board 20 or its one surface and the circuit-surface of the electronic part of form hollow portions between the respective step-surfaces of the recessed portion 21B of the circuit board 20 and the predetermined regions of the respective opposite circuit-surfaces thereto of the electronic part and to seal the electronic part. As a result the designed values of both wiring patterns and the constants of the characteristic impedance of passive elements, etc., which are formed on the circuit-surface of the electronic part can be maintained. |
