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SCL
has a state-of-the-art manufacturing facility for producing MEMS devices in
6” wafer size and has capability of design, fabrication, packaging and
testing. The design activities are taken up for the development of RF MEMS,
Temperature Sensor and Peizoresistive Pressure sensor etc. Designers
work closely with process engineers and produce production ready designs.
SCL’s MEMS Fabrication line includes the following process technologies :
CMOS processes are carried out in the 6” VLSI Fab and Post CMOS
Operations in Class-100 MEMS Fab. The protocols and facility planning ensure
that there is no cross contamination.
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Surface
micromachining |
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Process ID |
Structural Layer |
Sacrificial Layer |
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SNO |
Silicon Nitride |
Silicon Dioxide |
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SPO |
Poly Silicon |
Silicon Dioxide |
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SAO |
Aluminum |
Silicon Dioxide |
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Double Poly process, with stress free Polysilicon
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Vertical etch of structural layer through DRIE |
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Stiction free surface micromachining process
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Good selectivity of etchant with Aluminum |
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Option of
using Gold metallization, for best selectivity with surface
micromachining etchant |
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Bulk Micromachining |
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Process ID |
Micromachining Side |
Etch Stop |
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BBE |
Back Side |
Electro Chemical Etch Stop |
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BBT |
Back Side |
Timed Etch Stop |
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BFT |
Front Side |
Timed Etch Stop |
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BBD |
Back Side |
DRIE based process |
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BFD |
Front Side |
DRIE based process |
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KOH (Wet)
bulk micromachining : |
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Silicon diaphragms upto 25μ thickness with Timed KOH
process and upto 10μ thickness, using Electro-chemical etch stop
process |
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Protective coating and
fixture used for protecting active side of the wafer during KOH etching |
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Silicon Oxide- Nitride stack used as masking layer
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Deep
Reactive Ion Etching (DRIE) : |
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Vertical etching and through-and-through wafer etching
using DRIE Bosch process |
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Photoresist
and Silicon Oxide used as masking layer |
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Substrate Bonding
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Glass to Silicon substrate
(Anodic bonding) and Silicon to Silicon wafer bonding (Eutectic Bonding)
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Upto three wafer stack (
Thickness < 2 mm) |
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≤ 2µ Alignment accuracy
using bottom side alignment system |
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Vacuum (upto 5 x10-5 mBar) and Overpressure (< 2.5 bar,
with Nitrogen ambient) bonding conditions possible |
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Special Metal
deposition |
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