Laminated substrate manufacturing method and laminated substrate manufactured by the method
Adhesion of particles due to static buildup during a laminated substrate manufacturing process is constrained, so as to reduce generation of a void or a blister in a lamination step and improve yield. A laminate 13 is formed by superimposing a first semiconductor substrate 11 , which is to be an active layer, on a second semiconductor substrate 12 , which is to be a supporting substrate, via an oxide film 11 a . Electric resistance of either or both of the first and second semiconductor substrates 11 and 12 before superimposition is 0.005-0.2 Ωcm.
1. A method for manufacturing a laminated substrate, comprising forming a laminate by superimposing a first silicon substrate, as an active layer, on a second silicon substrate, as a supporting substrate, via an oxide film,
wherein the electric resistivity of both of said first silicon substrate and said second silicon substrate before superimposition is 0.005-0.2 Ωcm,
wherein a wafer chuck for conveying both the first and second silicon substrates is formed with a conductive material and is grounded, and
wherein the static electricity in both substrates is discharged from the grounded wafer chuck when superimposing both substrates.
2. The method according to claim 1 , wherein the laminated substrate is maintained in a reduction atmosphere containing hydrogen gas at 1000-1350° C. for 1-10 hours after lamination of said laminate.
3. The method according to claim 1 , wherein said laminate is formed by superimposing said first silicon substrate on said second silicon substrate after ion implantation is carried out in said first silicon substrate to form an ion implantation region in said first silicon substrate, and wherein said active layer is then formed on said second silicon substrate via said oxide film by separating said laminate at said ion implantation region.
4. The method according to claim 1 , wherein said active layer is formed by polishing said first silicon substrate to a predetermined thickness after heat-treating said laminate for lamination.