PRINTED SUBSTRATE

PROBLEM TO BE SOLVED: To provide a printed substrate, which can suppress the cracking of the boundary part with a conductor pattern at an insulating layer when heat is applied. SOLUTION: Insulating layers 3, 4, 5, 6 and 7 are laminated on a core layer 2. In the forming surface of the insulating layers 3, 5 and 7, Cu conductor patterns 8, 9 and 10 are formed. Around the conductor patterns 8-10 in the forming surfaces of the insulating layers 3-7, closed curve shaped patterns 11, 12, 13, 14 and 15 are formed in the ring pattern. Furthermore, the closed curve shaped patterns 11-15 comprise Cu, whose linear thermal expansion coefficient is smaller than the insulating layers 3-7. When heat is applied, the thermal stress in the region surrounded by the closed linear patterns 11-15 is dispersed by the hydrostatic pressure effect by the closed curved patterns 11-15. The thermal stress at the boundary part with the conductor patterns 8-10 in the insulating layers 3-7 becomes weak.