Wafer processing laminate, temporary adhesive material for wafer processing, and method for manufacturing thin wafer

A wafer processing laminate comprising a temporary adhesive material layer formed on a support and a wafer laminated on the temporary adhesive material layer, the wafer having a circuit-forming front surface and a back surface to be processed, wherein

• the temporary adhesive material layer has a composite temporary adhesive material layer having a two-layer structure of a first temporary adhesive layer and a second temporary adhesive layer,
• the first temporary adhesive layer comprising a thermoplastic resin layer (A) that is releasably adhered to the front surface of the wafer;
• and
• the second temporary adhesive layer comprising a photo-curing siloxane polymer layer (B) laminated on the first temporary adhesive layer, wherein the photo-curing siloxane polymer layer (B) is a cured layer of a photo-curing siloxane composition containing:
• (B-1) an organopolysiloxane having two or more alkenyl groups in a molecule thereof;
• (B-2) an organohydrogenpolysiloxane having two or more silicon atom-bonded hydrogen atoms (Si—H groups) per molecule in such an amount that a mole ratio of the Si—H groups in the component (B-2) to the alkenyl groups in the component (B-1) ranges from 0.3 to 10;
• and
• (B-3) 1 to 5,000 ppm of a photoactive hydrosilylation reaction catalyst based on a total mass of the component (B-1) and the component (B-2) in terms of an amount of metal atoms.