Method for processing a substrate assembly and wafer composite structure

A method for processing a substrate assembly with a semiconductor device layer, the method comprising:

• arranging an auxiliary carrier at the substrate assembly such that a connection surface of the auxiliary carrier and a first surface of the substrate assembly directly adjoin each other;
• fixedly attaching the auxiliary carrier to the substrate assembly by melting a carrier portion of the auxiliary carrier to a substrate portion of the substrate assembly;
• processing the semiconductor device layer of the substrate assembly with the auxiliary carrier fixedly attached to the substrate assembly;
• and
• separating the auxiliary carrier from the substrate assembly by a re-melting process.

A method for processing a substrate assembly with a semiconductor device layer, the method comprising:

• arranging an auxiliary carrier at the substrate assembly such that a connection surface of the auxiliary carrier and a first surface of the substrate assembly directly adjoin each other, the auxiliary carrier having an opening;
• fixedly attaching the auxiliary carrier to the substrate assembly by melting a carrier portion of the auxiliary carrier to a substrate portion of the substrate assembly;
• and
• processing the semiconductor device layer of the substrate assembly with the auxiliary carrier fixedly attached to the substrate assembly.

A wafer composite structure, comprising:

• an auxiliary carrier with a connection surface;
• and
• a substrate assembly with a semiconductor device layer and a first surface,
• wherein the auxiliary carrier and the substrate assembly are locally fused only in fused portions of the auxiliary carrier and the substrate assembly,
• wherein the fused portions are laterally separated from each other by at least one unfused portion.