Temporary Handling Technology for Advanced Wafer Level Packaging Applications based on Adhesive Bonding and Laser Assisted De-Bonding

This manuscript describes process scenarios for advanced wafer level packaging which are enabled by temporary bonding and de-bonding capabilities but exceeding the skills of classical thin wafer handling approaches. An adhesive bonding and laser assisted de-bonding technology which is a proven platform for TSV wafer processing is introduced to be a versatile basis for these different kinds of handling scenarios. By adapting this base technology, single devices can be temporary fixed at carrier wafers, subsequently processed in parallel and finally release from the carrier wafers. Furthermore, processes for thin IC wafers can be adapted to end up with singulated thin ICs equipped with temporary bonded carrier dice on their backside which act as mechanical support during a standard pick&place and reflow process scheme. Another process scenario allows the custom specific fabrication of cap structures at wafer level and subsequent transfer bonding from a donor wafer to a target wafer. A further scenario allows the fabrication of thin film multilayer structures at carrier wafers and their subsequent release from these carrier wafers. The manuscript firstly describes the general process flow for adhesive bonding and de-bonding by laser release technology. Secondly, technical back ground and motivation as well as technological solutions for the above mentioned process scenarios are presented and discussed in detail. Special focus is drawn on the corresponding temporary handling processes which are based on adhesive bonding and laser assisted de-bonding. All described processes are proven at 200 mm wafer scale.