Post on 16-Aug-2015
Spacer for Resonant Cavity
Imaging Biosensor
Elaine Mau, Rutgers University
� [How it works] Resonant Cavity
Imaging Biosensor
(RCIB)
Photodetector Array
Si Si-SiO2
reflector
Collimated
Light
Si
Cavity
Si-SiO2
reflector
microarray
Recorded
Signals
II
λ
I
λ
I
λ
I
λ
Methods
Part 1: Fabrication of the spacer
Part 2: Employment of wafer bonding techniques
a) Gravity
c) Photoresist
Part 3: Examining resonance to determine the viability
of each technique
a) Distance between Mirrors
b) Tilt
c) Stability
Spacer Specifications
Part 1: Fabrication of Spacer
Mask 1: Channels
Part 1: Fabrication of Spacer
Mask 2: Donuts
Front Side Etching
Part 1: Fabrication of Spacer
Mask 2: Donuts
Back Side Etching
Part 2: Employment of wafer bonding
techniques
Part 2: Employment of wafer bonding
techniques
� Gravity
� Photoresist
Part 3: Measurements
Part 3: Measurements
� Distance Between Two Mirrors
� Tilt
� Stability
ResultsGravity Photoresist
Qualities Gravity Photoresist
Average Mirror Separation 225 µm 210 µm
Tilt 2.2 nm/µm 0.22 nm/µm
Stability Somewhat Somewhat
Conclusion
� Alternative method performed for Deep Reactive Ion
Etching is not recommended
� Excessive handling
� Etching channels using method describe is possible
� Etching through for donuts using method describe may be
done using backside etching; however, there is lack of
alignment
� Using photoresist as adhesive is promising, but
further tests must be preformed
� Sandwich is tighter with photoresist
� Tilt of photoresist sandwich was ten times more
Acknowledgements
Thank you Professor Ruane,
David Bergstein, Phillip Spuhler,
Arthur Wu, and Abdol Hossein
Entekhobi
Boston University and National
Science Foundation for providing
this research opportunity!