Self-alignment method on a temperature-controlled transfer

We propose a method to fix the positioning error of transferred bare chips on a substrate after the Temperature-Controlled Transfer (TCT) that we have previously developed. This TCT method is important for large area integration of heterogeneous materials. In the TCT process, the bare chips on an adhesive sheet are transferred and electrically connected to the substrate via Low-Melting Point Solder (LMPS). We reflowed the LMPS and used the surface tension of the LMPS to self-align the bare chips in position on the substrate. We experimentally confirmed that the self-alignment works when contact pads on the bare chip and the substrate were overlapped. The positioning error after the self-alignment process was within 0-15 % of the contact pad size.