Deep reactive ion etching of Pyrex glass using SF6 plasma

Deep reactive ion etching of Pyrex glass has been characterized in sulfur h exafluoride plasma (SF6). High etch rate (similar to0.6 mum/min) was demons trated under a condition of low pressure (0.2 Pa) and high self-bias (-390 V) by using a magnetically enhanced inductively coupled plasma reactive ion etching. Vertical etch profile (taper angle similar to 88 degrees), high a spect ratio (>10) and through-wafer etching of Pyrex glass (200 mum in thic kness) were achieved under the condition by using thick (20 mum) and vertic al electroplated nickel film as mask. The vertical etch profile was achieve d when the mask opening is narrower than 20 mum because the deposition of n onvolatile product on the sidewall is reduced. A novel etching technique "s coop-out etching" was demonstrated by using the present etching characteris tics. (C) 2001 Elsevier Science B.V. All rights reserved.