CIRCUIT BOARD AND MULTI-CAVITY CIRCUIT BOARD

摘要

[Problem] To provide a ceramic circuit board in which a side wall surrounding a cavity is thinned and the overall size is reduced, and a multi-cavity circuit board which has a plurality of said circuit boards and minimizes the problem that the brazing filler metals placed on each conductive layer that is formed on each surface of the adjoining circuit boards form a bridge when connecting a metal frame therewith. [Solution] A circuit board (1) is provided with: a substrate body (2) which is formed of a plate-like ceramic (S) and has a front surface (3) and a rear surface (4) with a height (H) of 0.8mm or less between the front surface (3) and the rear surface (4); a cavity (10) which is opened on the front surface (3) of said substrate body (2) and has a rectangular shape when viewed as a plane; and a side wall (5) which has a thickness (T) of 0.3mm or less between the side face (12) of the cavity (10) and the side face of the substrate body (2). The circuit board (1) includes: a conductive layer (16) which has a rectangular shape when viewed as a plane and is formed on the front surface (3) of said substrate body (2) and is formed so as to surround the opening of said cavity (10); a ceramic surface (7) which has a frame-like shape when viewed as a plane and is adjacent to said conductive layer (16) and is located along the outer peripheral side of the front surface (3) of the substrate body (2); and a via conductor (15) which is formed in the substrate body (2) along the side face (12) of the cavity (10) between the bottom face (11) of the cavity (10) and said front surface (3), the via conductor having a part (15a) exposed on the side face (12) of the cavity (10) while being connected with said conductive layer (16) at the upper end thereof.