Laser Processing in Semiconductor Manufacturing

Laser processing can be found everywhere in the semiconductor processing chain. The motivations are flexibility, precision, and high cost savings. This presentation focuses on three new and innovative use cases for laser processing in the semiconductor back end.

Laser annealing is a well-known process. New is the ohmic contact-formation process used for the full-surface rear-side metal contact of silicon carbide (SiC)-based power devices. For the previously thick wafers, the metal-silicide interface was manufactured by flash lamp tool without damaging the structured front side. For thermal and electrical reasons, a transition to thin wafers is required, and only a short-pulse UV laser is selective enough to generate the necessary temperatures >1000 °C on the back, whereas the front is only exposed to temperatures <100 °C. Second, an annealing process for a completely different application is the selective laser formation or "pinning" of integrated monolithic giant magnetoresistance (GMR) and tunnel-magnetoresistance (TMR) sensor devices. Instead of processing single sensors, and the subsequent separation and packaging of sensor bridges, the process can "program" the sensors for e-compass and position detection in one single process step, with very high throughput and yield and enormous cost advantage. The final use case is thermal laser separation (TLS), or dicing, for products that require perfect edges, minimum particle generation, and high throughput.

About the presenter
Hans-Ulrich Zühlke, Ph.D., studied instrument technology at the Friedrich Schiller University in Jena. In 1998, he received his doctorate from the University of Jena. He then worked at JENOPTIK, most recently for 10 years in the field of laser applications for the semiconductor industry. In 2014, Zühlke started as market development manager semiconductor at 3D-Micromac. In the last few years, he was the product manager for semiconductor products who was responsible for various laser applications, including dicing, structuring, and various annealing processes. In January, he will take up a new position as project manager at Jena Optronic.