Thesis
Cryogenic deep reactive ion etching and bonding of through silicon wafer vias
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/103151
Abstract
Positrons being an antiparticle annihilate upon coming in contact with electrons, which means any form of matter. To store a large number of positrons in one place, a new approach is being followed where thousands of 100 mm or smaller diameter holes are being etched through Si wafers. Two hundred of these wafers will be stacked axially to form cylindrical tube-like structures by combining these holes. Deep Reactive Ion Etching at cryogenic temperatures is being carried out to etch high aspect ratio, through wafer holes with smooth and straight sidewalls. Etching parameters like chamber pressure, temperature, Radio Frequency (RF) power, Inductively Coupled Plasma (ICP) power, SF6/O2 gas flow, and O2 gas percentage were tuned in order to reach a recipe which gives the best possible etching results. Experiments were carried out to address issues like bowing, notching, undercut, non uniform etch rates across a wafer, and preferential etching in certain crystal planes. Trench widths were calibrated to match etch rates between all the features contained in the wafer. As a result, through wafer holes have been etched with straight sidewalls (89.9o -90.1o ), smooth surfaces and high aspect ratios (5:1) with minimal defects.
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Details
- Title
- Cryogenic deep reactive ion etching and bonding of through silicon wafer vias
- Creators
- Ankita Verma
- Contributors
- Kelvin G. Lynn (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525381201842
- Language
- English
- Resource Type
- Thesis