| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an inexpensive power module substrate having both high thermal conductivity and high bending strength, and high in all mechanical reliability.SOLUTION: A power module substrate 10 comprises: a circuit copper plate 12 for mounting a semiconductor element 14 to form an electrical continuity circuit; and a heat dissipation copper plate 13 for dissipating heat generated from the semiconductor element 14, the circuit copper plates and the heat dissipation plate being joined on one main face and the other main face of a ceramic substrate 11, respectively. In the power module substrate, the ceramic substrate 11 contains alumina (AlO) as a main constituent, and zirconia (ZrO), and comprises joined bodies 20, 20a, 20b of two kinds of an alumina ceramic flat plate containing zirconia at a high rate and an alumina ceramic plate containing zirconia at a low rate, the alumina plates being obtained by adding a sintering assistant comprising at least one or more of yttria (YO), calcia (CaO), magnesia (MgO) and ceria (CeO) and having a different percentage content of zirconia each other.</p> |
