MEMS Process - Analog/Mixed-Signal Semiconductor Foundry · PDF filetechnology - Sensor...
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... because the world is analog. - Single, double or triple axis inertial sensor using cavity SOI wafer based technology - Sensor elements formed by silicon DRIE process - Optional top and bottom metal layers - Top cap wafer: Silicon with etched cavities and bond pad openings - Cost effective wafer level packaging by wafer bonding Process - Recessed fingers enable sensing in Z-direction - 100% efficient silicon mass possible - Refilled isolated trenches - Metal connections to the movable sensor structures - Wire crossing allowed - Small device size - Low parasitic capacitances - Low inside cavity pressure Features yaw roll pitch Top view, open sensor structure Interdigital finger structures and seismic mass Inertial sensor wafer before wafer-level packaging 1...3-Axis Surface Micromachining Process for Inertial Sensors Process Family XMB10 MEMS Process Schematic cross section Anchor Glass frit Cavity wafer Buried oxide Comb finger with reduced height Sensor pad Trench isolated area Metal line Isolator under metal Top cap wafer Membrane wafer
Transcript of MEMS Process - Analog/Mixed-Signal Semiconductor Foundry · PDF filetechnology - Sensor...
... because the world is analog.
- Single, double or tripleaxis inertial sensor usingcavity SOI wafer basedtechnology
- Sensor elementsformed by siliconDRIE process
- Optional top andbottom metal layers
- Top cap wafer: Siliconwith etched cavities andbond pad openings
- Cost effective waferlevel packaging bywafer bonding
Process
- Recessed fingers enablesensing in Z-direction
- 100% efficientsilicon mass possible
- Refilled isolated trenches
- Metal connections to themovable sensor structures
- Wire crossing allowed
- Small device size
- Low parasitic capacitances
- Low inside cavity pressure
Features
yaw
roll pitch
Top view, open sensor structure
Interdigital finger structures and seismic mass
Inertial sensor wafer beforewafer-level packaging
1...3-Axis Surface Micromachining Processfor Inertial Sensors
Process Family XMB10
MEMS Process
Schematic cross section
Anchor
Glass frit
Cavity wafer
Buried oxide
Comb finger withreduced height
Sensor pad
Trench isolatedarea
Metal line
Isolatorunder metal
Top cap wafer
Membrane wafer
Marketing & Sales Headquarters
X-FAB MEMS Foundry GmbH
Haarbergstr. 67, 99097 Erfurt, Germany
Tel.: +49-361-427-6000
Fax: +49-361-427-6161
Web: http://www.xfab.com
General Information
Technology/Design Support
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Photographs of sensor structures
- Detection of capacity changes,
e.g. caused by inertial forces
- Feasibility of electrical stimulation,
e.g. detection of Coriolis forces (Gyro's)
- Sensor capacity consists of interdigital structures
- Element moving or finger bending
takes place in X-Y-Z planes
Sensor principle
Simplified schematics of interdigital andparasitic ground capacities
GND
sense
supply
Top view: metal wires, anchors and finger structures
SEM view: isolation trenches and metal lines
Design schematic of 3-axis gyro
MEMS Process
1...3-Axis Surface Micromachining Process for Inertial Sensors
XMB10
Typical Technological Characteristics
Wafer size
Thickness device wafer
Thickness buried oxide
Resistivity device wafer
Minimum trench width
Minimum beam width
Total thickness wafer stack(sensor with top cap)
Inside cavity pressure(adjustable)
6 inch
15 µm or 30 µm
600 nm
0.075 cm
2 µm
2 µm
600 ... 800 µm
< 0.005 ... 0.4 bar
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