| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent reliability in the connection of a semiconductor device to an external electric circuit from being reduced by a breakage in a low- melting point brazing material for connecting the connecting pads of a wiring board to the external electric circuit. SOLUTION: A wiring board is made of an electrically insulating material and is formed of an insulating base material 1 having a semiconductor mounting part 1a on the top, many circular connection pads 6 formed on the bottom of the insulating base material 1 and connected to the circuit wirings 8a of the external electric circuit substrate 8 via low-melting point brazing material 7, and plural wiring conductors 2 extending from the mounting part 1a of the insulating base material 1 to the connection pads 6. The connection pad 6 has an annular gap 6b satisfying the following formula near its outer periphery, 1-(0.028/tanX)<=r/R<=1-(0.009/tanX), where r is the inner radius of the annular gap formed in the connection pad (mm) R is the radius of the connection pad (mm) and X is the effective tip angle of crack produced on the low-melting point material (rad).</p> |
