Circuit substrate device, method for producing the same, semiconductor device and method for producing the same

摘要

A circuit substrate device composed of a circuit unit 2 and a multi-layer wiring substrate 3 in which a pattern conductor of the circuit unit 2 may be prevented from being warped or inundated. The circuit substrate device includes a circuit unit 2 having a pattern conductor formed by a thin film technique, and an insulating layer, and a multi-layer wiring substrate 3 having a connecting terminal portion 14 exposed from its major surface. The circuit unit is formed on a dummy substrate. The circuit unit is connected to the multi-layer wiring substrate 3 so that the pattern conductor is connected to the connecting terminal portion 14. The dummy substrate is then removed to give a structure comprised of the circuit unit 2 formed on the multi-layer wiring substrate 3. The pattern conductor of the circuit unit 2 is freed of warping or inundations along the direction of thickness of the circuit unit 2.