| 摘要 |
PROBLEM TO BE SOLVED: To restrain generation of cracks of an insulating board which are caused by temperature change of a module, by forming the end portion of bounding material in such a manner that it exists outside the end portion of a conducting foil. SOLUTION: The area of a bonding material 2 is formed wider than that of a conducting foil circuit pattern 3. Since an end portion 14 of the conducting foil circuit pattern does not coincide with an end portion 15 of the bonding material, the concentrated stress applied to a ceramic board is relieved independently of the thickness of the conducting foil pattern 3. By forming the conducting foil circuit pattern 3 inside the pattern of the bonding material 2, and making the bonding material 2 coming directly into contact with the ceramic board thinner than the circuit pattern, the stress concentrating in the end portion 15 of the bonding material can be reduced. Thereby, reliability of the ceramics board can be ensured, when the conducting circuit pattern 3 is thickened in order to apply a large current. Application to the corner part of the conducting foil circuit pattern where stress concentration is apt to happen is especially effective.
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