| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device, which can suppress the ripple of the impedance of wiring after mounting of a high frequency semiconductor element, and also can remove the reflection of a high frequency signal due to change in line width and further enables a defective element after its mounting to be replaced easily, having a mounting structure improved in both the aspect of high frequency property and the aspect of manufacture process. SOLUTION: This high-frequency semiconductor device possesses a wiring board 21, which has a recess 22a at the topside of a dielectric substrate 22 and in which a line conductor 24 is made around the opening and earth conductors 23 and 23a are made at the lowerside and at the bottom of the recess 22a, a wiring board 25 for mounting which is attached to cover the opening of the recess 22a and whose connecting electrode 28a is abutted and connected to the line conductor 24, and a high-frequency semiconductor element 31 which is connected to a mounted electrode 30a. In this case, the wiring board 25 for mounting comprises a main dielectric layer 26, which is larger than the dimension of the opening of the recess 22a and moreover whose relative dielectric constant is larger than that of dielectric substrate 22, a sub dielectric layer 27 whose relative dielectric constant is smaller than that of the main dielectric layer 26, a line conductor 28 for mounting which is made between the main dielectric layer 26 and the sub dielectric layer 27 from a connecting electrode 28a, and a through-conductor 30 which connects the line conductor 28 for mounting to the mounted electrode 30a. |
