LOW-TEMPERATURE BONDING OF CU ON SI3N4 US ING LASER-ABLATION PROCESS

Low temperature bonding of a Cu specimen on a Si3N4 plate was examined . Si3N4 plates were irradiated with KrF excimer laser beam in vacuum. The energy density of laser was 0.3 J/mm(2). At the laser irradiation area Si3N4 was decomposed into Si and N-2 and then thin Si layer was f ormed on Si3N4. XPS analysis revealed that the thickness of the thin S i layer was 0.04 mu m. An Ar ion sputtered Cu specimen was pressed on a Si3N4 plate through thin Si layer at temperatures of 560 similar to 630 K for 3.6 ks in vacuum. The bonding strength was 100-200 MPa and t he Si layer was essential for low temperature bonding of Cu and Si3N4.