Chip-side-healing as a basis for robust bare-chip assemblies

During their life cycles, semiconductor devices are exposed to different mechanical loads as a result of assembly and packaging processes as well as by stresses due to environmental conditions during operation. Especially, in modern applications like high temperature sensors the die-strength and the fracture resistance of the used semiconductor are important factors for the system reliability. They often develop high stresses in the chips. The die-strength is considerably influenced by the wafer dicing because of process-induced damages, which are generated at the side walls of chips. Chip-side-healing (CSH) is a term for the selective removal of dicing damages with the aim to increase the die-strength. In this work, two new CSH-processes are evaluated. The first one uses xenon difluoride (XeF₂) as the etching medium and the second process works with fluorine radicals to remove the damages. Both processes can remove all of the dicing damages. After the CSH the bending strength was nearly four times higher than without the aforementioned processes. In comparison to six common dicing techniques, diamond-scribing, water-jet-laser-dicing, stealth-dicing, blade-dicing, deep-reactive-ion-etching and thermal-laser-separation, CSH shows better potential to increase the thermal-mechanical reliability of semiconductors.