Kerfless Wafering for Silicon Wafers by Using a Reusable Metal Layer

AbstractIn literature different methods can be found to cleave silicon wafers or chips from the silicon block. These techniques are interesting for cost effective PV production, since they are kerf-less and material consumption for one wafer is at a minimum. In this paper a new method is proposed, which is based on mechanical loads in a layer system of silicon, glueing material, and a re-usable metal stripe. In its final stage, this method does not need to heat up and cool down the whole silicon crystal for each spalling cycle and thus may be considerably more time and energy efficient than previous thermal spalling methods. First experiments were successfully performed to thermally cleave (10x10) mm2 silicon chips. By using analytical and numerical models, more insight in the fracture mechanical process was given and important material and geometry parameters were identified in order to optimize the process