Patent ID: 7083759

Claim:
A method of producing a material for heat dissipation substrate for mounting a semiconductor chip, comprising the steps of: press-forming molybdenum powder having an average particle size of 2–4 μm at a pressure of 100–200 MPa to obtain a molybdenum powder compact; impregnating melted copper into a void between powder particles of the molybdenum powder compact in a nonoxidizing atmosphere at 1200–1300° C. to obtain a composite of molybdenum and copper which contains 70–60% molybdenum in weight ratio, the balance copper; primary rolling the composite in one direction as a first rolling direction at a temperature of 100–300° C. and at a working rate of 50% or more; and secondary rolling the composite as cold rolling in a direction intersecting with the one direction as a second rolling direction at a working rate of 50% or more after the step of primary rolling, wherein a total working rate is 75% or more when primary rolling and secondary rolling so as to produce a rolled composite of molybdenum and copper which has a coefficient of linear expansion of 8.2×10 −6 /K or less at 800° C. in the second rolling direction.