Laser-Induced Forward Transfer for Assembly of Silicon Micro-Chiplets

The semiconductor industry can no longer count on monolithic integration to accomplish the economic benefits of the previous era. Now, new packaging solutions are being adopted to achieve the commercial advantages that were previously met with silicon scaling. The role of heterogeneous integration, especially micro-chiplets, is pivotal in this new era. Several techniques are being investigated to allow for massive but still precise assembly of small semiconductor chiplets, including contact transfer printing, fluidic assembly, and laser-induced forward-transfer (LIFT) printing. In addition to very high transfer rates, laser-based mass transfer offers the advantages of being truly selective, and extremely flexible in terms of dimensions and materials. This study presents a combined approach for micro-chiplet preparation and assembly, with a systematic investigation into the transfer accuracy of 200×200 µm2 Si micro-chiplets as a function of various experimental conditions which would be useful for heterogeneous integration of different micro-chiplets in systems-in-package applications.