What could be the reason for non-uniform etching of ST-cut quartz in BOE HF. What is the etch rate of ST-cut quartz in HF?

Some parts of the chip (5x5mm) are ~70nm deep, whereas other parts are ~470nm deep. Details: ST-cut quartz was etched in BOE HF (1:1) solution for 10min at room temperature. Prior to etching some...

06 June 2017 3,123 3 View