| 摘要 |
PROBLEM TO BE SOLVED: To enable a semiconductor device to be enhanced in mounting density and to operate at a high speed and high frequencies, without deteriorating its characteristics. SOLUTION: When a semiconductor chip 20 is mounted on a wiring board 30 facing downward, a sacrificial layer which is capable of disappearing and provided on a wiring board 30, confronting a circuit surface 21 of the semiconductor chip 20, the sacrificial layer is made to disappear after the semiconductor chip 20 is mounted on the wiring board 30, and a cavity 41 is formed between the wiring board 30 and the circuit surface 21 of the semiconductor chip 20. The cavity 41 is formed as was described, by which the semiconductor chip 20 is capable of operating at a high speed and high frequencies, without incurring increase in capacity or a propagation mode change in surface acoustic waves due to a sealing member which coats the semiconductor chip 20. |
