There is shown a stack including a substrate material temporarily fixed on a support via a temporary fixing material, wherein the temporary fixing material includes a temporary fixing material layer (I) in contact with the support-facing surface of the substrate material, and a temporary fixing material layer (II) formed on the support-facing surface of the layer (I), wherein the temporary fixing material layer (I) is formed of a temporary fixing composition containing a polymer (A) and a release agent (B) which contains a functional group capable of reacting with the polymer (A) to form a chemical bond.