| 摘要 |
PROBLEM TO BE SOLVED: To provide a circuit substrate which has a high joining strength of a wiring circuit layer to a sintered material and which does not bring about a fault even when a plating layer is formed, and to provide a method for inexpensively manufacturing the same. SOLUTION: The circuit substrate comprises an insulating substrate 1 containing a silicon nitride as a main crystal phase, a flat pattern layer 3 provided on the main surface 2 of an insulating substrate 1, and a wiring circuit layer 5 provided on an opposed main surface 4 disposed at an opposite side to the main surface 2, In the substrate, the surface roughness Rmax of the main surface 2 is 5 to 10μm, and the main surface 4 has smaller surface roughness Rmax than that of the main surface 2. |
