WIRING BOARD FOR HIGH-FREQUENCY SIGNAL AND SEMICONDUCTOR MODULE FOR HIGH-FREQUENCY SIGNAL USING IT

摘要

PROBLEM TO BE SOLVED: To avoid the concentration of electric currents by protruding the upper end sections of signal lines laid in wiring forming grooves which are composed of recessed sections having cross sections representing continuous curved surfaces and formed on the surface of a dielectric layer formed on a substrate from the surface of the dielectric layer. SOLUTION: A ground layer 3 and a dielectric layer 4 are successively formed on a substrate 2. Signal lines 5 are buried in recessed sections which are formed on the surface of the dielectric layer 4 and have cross sections representing continuous curved surfaces at a depth of H2 and the end faces of the lines 5 are protruded from the surface of the dielectric layer to a height of H1 . That is the distances from the protruded front ends of the lines 5 to the bottoms of the recessed sections are represented by H(=H1 +H2 ) and the value of the H corresponds to the thickness of the signal lines 5. Since the signal lines 5 are brought into contact with the dielectric layer 4 on the curved surfaces only and no corner section exists in the contacting plane between the dielectric layer 4 and signal lines 5, the concentration of electric currents can be avoided.