Vertical integration of array-type miniature interferometers at wafer level by using multistack anodic bonding
| Autor: | Maik Wiemer, Justine Lullin, Joerg Froemel, Wei Shan Wang, Christophe Gorecki, Jorge Albero, Nicolas Passilly, Sylwester Bargiel, Thomas Gessner, Tom Enderlein |
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| Rok vydání: | 2016 |
| Předmět: |
Microelectromechanical systems
Microlens Materials science business.industry Mirau interferometer 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences law.invention 010309 optics Interferometry Optics Anodic bonding law 0103 physical sciences Wafer 0210 nano-technology business Flip chip Beam splitter |
| Zdroj: | SPIE Proceedings. |
| ISSN: | 0277-786X |
| DOI: | 10.1117/12.2229884 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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