abstract |
This relates to a multi-layer composite metallic sheet having a predetermined coefficient of thermal expansion for use as a heat sink and mounting arrangement when bonded to a ceramic substrate. Since copper has a coefficient of thermal expansion greater than that of ceramic and molybdenum has a coefficient of thermal expansion less than that of ceramic, layers of copper and molybdenum can be combined to provide a composite having a coefficient of thermal expansion equal to that of ceramic. To avoid a bimetallic effect, a core layer of a fused metal is sandwiched between two outer layers of the second metal. |