摘要 |
Production of a curved metallised ceramic substrate (1) for electrical or electronic components or circuits involves placing a green sheet (2) on the dished top surface of a mould element, e.g. a mould plate of heat resistant material, and then heat treating at ≥ 1200 degrees C for a predetermined time. Preferably, one or more green sheets are placed on a concave curved surface of the mould element, a weight (a heavy plate or a counter-mould element) is placed on the sheet or sheet stack and heat treatment is carried out in two successive steps, the second step being carried out at a lower (e.g. 100 degrees C lower) temperature than that of the first step. The metallisation (3, 4) is preferably applied onto the curved ceramic sheet (2) by direct copper bonding (DCB) of a copper foil or by bonding a metal foil using an active solder paste (e.g. of 40% Ag, 55% Cu and 5% Ti) or a solder foil (preferably a thin oxidised copper foil). |