TY - GEN
T1 - Vertical integration of array-type miniature interferometers at wafer level by using multistack anodic bonding
AU - Wang, Wei Shan
AU - Wiemer, Maik
AU - Froemel, Joerg
AU - Enderlein, Tom
AU - Gessner, Thomas
AU - Lullin, Justine
AU - Bargiel, Sylwester
AU - Passilly, Nicolas
AU - Albero, Jorge
AU - Gorecki, Christophe
PY - 2016/1/1
Y1 - 2016/1/1
N2 - In this work, vertical integration of miniaturized array-type Mirau interferometers at wafer level by using multi-stack anodic bonding is presented. Mirau interferometer is suitable for MEMS metrology and for medical imaging according to its vertical-, lateral- resolutions and working distances. Miniaturized Mirau interferometer can be a promising candidate as a key component of an optical coherence tomography (OCT) system. The miniaturized array-type interferometer consists of a microlens doublet, a Si-based MEMS Z scanner, a spacer for focus-adjustment and a beam splitter. Therefore, bonding technologies which are suitable for heterogeneous substrates are of high interest and necessary for the integration of MEMS/MOEMS devices. Multi-stack anodic bonding, which meets the optical and mechanical requirements of the MOEMS device, is adopted to integrate the array-type interferometers. First, the spacer and the beam splitter are bonded, followed by bonding of the MEMS Z scanner. In the meanwhile, two microlenses, which are composed of Si and glass wafers, are anodically bonded to form a microlens doublet. Then, the microlens doublet is aligned and bonded with the scanner/spacer/beam splitter stack. The bonded array-type interferometer is a 7- wafer stack and the thickness is approximately 5mm. To separate such a thick wafer stack with various substrates, 2-step laser cutting is used to dice the bonded stack into Mirau chips. To simplify fabrication process of each component, electrical connections are created at the last step by mounting a Mirau chip onto a flip chip PCB instead of through wafer vias. Stability of Au/Ti films on the MEMS Z scanner after anodic bonding, laser cutting and flip chip bonding are discussed as well.
AB - In this work, vertical integration of miniaturized array-type Mirau interferometers at wafer level by using multi-stack anodic bonding is presented. Mirau interferometer is suitable for MEMS metrology and for medical imaging according to its vertical-, lateral- resolutions and working distances. Miniaturized Mirau interferometer can be a promising candidate as a key component of an optical coherence tomography (OCT) system. The miniaturized array-type interferometer consists of a microlens doublet, a Si-based MEMS Z scanner, a spacer for focus-adjustment and a beam splitter. Therefore, bonding technologies which are suitable for heterogeneous substrates are of high interest and necessary for the integration of MEMS/MOEMS devices. Multi-stack anodic bonding, which meets the optical and mechanical requirements of the MOEMS device, is adopted to integrate the array-type interferometers. First, the spacer and the beam splitter are bonded, followed by bonding of the MEMS Z scanner. In the meanwhile, two microlenses, which are composed of Si and glass wafers, are anodically bonded to form a microlens doublet. Then, the microlens doublet is aligned and bonded with the scanner/spacer/beam splitter stack. The bonded array-type interferometer is a 7- wafer stack and the thickness is approximately 5mm. To separate such a thick wafer stack with various substrates, 2-step laser cutting is used to dice the bonded stack into Mirau chips. To simplify fabrication process of each component, electrical connections are created at the last step by mounting a Mirau chip onto a flip chip PCB instead of through wafer vias. Stability of Au/Ti films on the MEMS Z scanner after anodic bonding, laser cutting and flip chip bonding are discussed as well.
KW - 3-D integration
KW - Anodic bonding
KW - MOEMS
KW - Mirau micro-interferometer
KW - Multi-wafer bonding
UR - http://www.scopus.com/inward/record.url?scp=84983058625&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84983058625&partnerID=8YFLogxK
U2 - 10.1117/12.2229884
DO - 10.1117/12.2229884
M3 - Conference contribution
AN - SCOPUS:84983058625
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Optical Micro- and Nanometrology VI
A2 - Osten, Wolfgang
A2 - Gorecki, Christophe
A2 - Asundi, Anand Krishna
PB - SPIE
T2 - Optical Micro- and Nanometrology VI
Y2 - 5 April 2016 through 7 April 2016
ER -