XERIC™ Silicon Etch

Advanced Dry Release Processing for Current and Next Generation MEMS Devices

A release etch process is required when creating a MEMS microstructure in order to remove the structural material, leaving the mechanical structure with clean and free surfaces. It is essential that removal of the sacrificial material does not damage or restrict the operation of the MEMS device. To ensure full performance and reliability, the remaining mechanical structure needs to be free from residues, particles and damage, and prepared for the application of an anti-stiction coating or packaging process steps.

XERIC Vapor Phase Dry Release Etching with Xenon DiFluoride (XeF2)

As a dry process, memsstar’s XERIC Xenon DiFluoride etching eliminates stiction in a single process. The patented memsstar XERIC sacrificial vapor release XeF2 (SVR-Xe) process is highly selective to a range of materials including aluminum, photoresist, silicon nitride and silicon dioxide. And, since it is isotropic, large undercuts of structures can be performed with no degradation in etch rate. The Xenon DiFluoride process is capable of etching a wide range of films including silicon (in all forms), molybdenum, germanium and tungsten.

Sacrificial Layers:
Polysilicon, amorphous silicon, single crystal silicon, molybdenum, germanium, tanatalum, tungsten

Protective Layers:
Stoichiometric PECVD nitride, silicon dioxide, thermal oxide, TEOS, quarts, PECVD oxide, spin-on oxide, Si-rich LPCVD nitride

memsstar’s XERIC Xenon DiFluoride etch offers industry-leading etch rates and our single wafer processingguarantees excellent repeatability and wide process windows to maximize performance and yield. A controlled vaporization system is used to deliver precise amounts of etch gas into a single-wafer vacuum chamber, which has a full range of process controls. The advantages of the XERIC process can be clearly evidenced in continuous-flow mode using memsstar’s CCFT technique. Unique process controls deliver tunable etch rates, uniformity and selectivity, with endpoint capability and thermal control of the wafer during etch.

XERIC Silicon Etch Features
Key characteristics Large process window to optimize process for any structure
Excellent selectivity with silicon nitride and silicon dioxide (<5% 1σ)
High selectivity to underlayer and mechanical materials
Industry-leading etch rates
High etch rates for undercut and blanket Si
Excellent uniformity (<5% 1σ)
Excellent repeatability (<5% 1σ)
No corrosion
No stiction
In-line controls—etch rate monitor, endpoint, temperature
Unique endpoint capability
Application examples Sensors, RF MEMS, micro bolometer arrays, accelerometers, RF switches, temperature gauges


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