Die Isolation Strategy for Suspended Devices Released by Dry Etching

A conventional way of device dicing is by manual saw dicing, stealth dicing of an entire wafer by defining the dicing lines at the design level. There are several factors that come into picture that at times limits our fabrication of critical MEMS devices, especially on those which have a released structure or a membrane amidst. We are familiar with the fact that MEMS release can happen in two different approaches, either wet or dry. Though there are existing self dicing techniques employed where “die singulation” happens by DRIE itself, we do find a lot of limitations when it comes to separation of devices with sensitive membranes or suspended structures. We will look at the conventional strategies of sample loading and unloading in a dry etch chamber, the difficulties that are to be considered while handling released structures, etc and showcase an easier way of doing the same by successfully releasing them without any damage to the membranes / suspended structures. The method we look at is at the design level, which can be a part of any device design that might require a die-by-die separation at the end.