Temporary bonding on the move towards high volume: A status update on cost-of-ownership

The ability to process thin wafers with thicknesses of 20–50um on front- and back side is a key technology for 3D stacked ICs (3Ds-IC). The most obvious reason for thin wafers is the reduced form factor, which is especially important for handheld consumer devices. However, probably even more important is that thinner wafers enable significant cost reduction for TSVs. Consensus has developed on the use of temporary bonding and debonding technology as the solution of choice for reliably handling thin wafers through back side processing steps. Temporary bonding and debonding comprises several processes for which yield is essential, as costly fully functional device wafers are being processed. The temporary bonding process yield has a major impact on the overall Cost of Ownership (CoO). On the other hand, throughput of the individual process steps like spin coating, bonding, cure, debonding and cleaning processes is the second determining factor for improved CoO. This paper should provide in depth understanding of CoO contributors to temporary bonding and debonding. Focus is put on the cost sensitivity of the major influencing contributor to temporary bond as well as debonding.