PURPOSE: To manufacture a ceramic substrate suitable for high density mounting with excellent heat dissipation efficiency and low wiring resistance between surface and back side by a method wherein fine and highly heat conductive thin plates formed by hot press process are bonded and laminated holding wiring materials.
CONSTITUTION: An SiC ceramic substrate made of SiC powder is formed by hot press process and the like under conditions such as temperature exceeding 2,000°C, pressure of 200kg/cm2 and atmosphere of Ar and sliced by a diamond blade to be ground by a sand-blast machine. Then ceramic thin plates 1 and wiring materials 2 are bonded into one body by laminating the ceramic thin plates 1 so far formed holding the wiring materials 2 between the thin plates 1 and heating for 10W30min at the temperature around 450°C in the air under pressurization. Then the laminated body is cut down to form a ceramic substrate. Kovar or 42 alloy with little difference in the thermal expansion coefficient compared with that of glass as bonding materials 3 are utilized as the lead frame to be the wiring materials 2. The ceramic substrate 7 may be provided with excellent heat dissipation efficiency making the fine wiring on the surface and back side easier since the SiC ceramic is of a fine construction with high heat conductance. Besides the wiring resistance between surface and back side may be lowered by the lead frame 4.
ISHIDA MASAKATSU
KOBAYASHI FUMIYUKI
