Patent ID: 8883564

Claim:
A method of producing an LED light emitting element, comprising: (a) infiltrating, by squeeze casting, an aluminum alloy comprising 3 to 20 mass % of silicon into an isotropic graphite material to obtain an aluminum-graphite composite, the isotropic graphite material having a graphitized coke with a porosity of 10 to 20 vol % as a raw material, the aluminum-graphite composite having a surface roughness (Ra) of 0.1 to 3 μm, a thermal conductivity of 150 to 300 W/mK at a temperature of 25° C., a maximum/minimum ratio of 1 to 1.3 for the thermal conductivity in three orthogonal directions, a coefficient of thermal expansion of 4×10 −6 to 7.5×10 −6 /K at a temperature of 25° C. to 150° C., a maximum/minimum ratio of 1 to 1.3 for said coefficient of thermal expansion in three orthogonal directions, and a three-point bending strength of 50 to 150 MPa; (b) cutting said aluminum-graphite composite using a multi-wire saw, under the following conditions (1) to (4): (1) the wires of said multi-wire saw having bonded abrasive grains made of diamond, C—BN, silicon carbide, alumina, or a combination thereof; and having an average grain size of 10 to 100 μm; (2) said wires having a wire diameter of 0.1 to 0.3 mm; (3) a wire delivery of said wires being 100 to 700 m/min; and (4) a cutting rate by said wires is 0.1 to 2 mm/min; to form a substrate with a thickness of 0.5 to 3 mm; and (c) mounting an LED-bearing chip and/or an LED package on one main surface of said substrate to produce the LED light emitting element.