| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a circuit module, with which the heat-dissipating property of a circuit component can be enhanced, a signal wiring layer can be arranged reasonably and the degree of freedom is increased when wiring pattern is determined. SOLUTION: A circuit module 20 is provided with a multilayer circuit substrate 21, having insulating layers 25a to 25e, signal wiring layers 26a to 26c and a heat transfer layer 27, and the circuit part 22 which is mounted on the surface 21a of the circuit substrate 21. A connection terminal 33 of the outer circumferential part of the circuit part 22 is connected to a pad 37 on the circuit substrate 21. The circuit substrate 21 has a number of via holes 40, which are electrically connected to the signal wiring layers. The via holes 40 are perforated on the mounting surface on the part opposite to the circuit part 22, the bottom part of each via hole 40 is adjacently located to the heat transfer layer 27 through the insulating layer 25a. Surface wiring layers 45a and 45b, which are electrically connected to the via holes 40, are arranged on the mounting surface of the circuit substrate 21.</p> |
