Investigation of Loading Effect in Deep Trench Lisa Technology

Zhang, Q. X.; Guo, Qiang; Li, J.; Liu, A. Q.

doi:10.1142/s1465876303001137

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…During the fabrication process, uneven depth beams occur as a result of the different trench widths beside the beams [156,157], as shown in Figure 3-24 where the finger gap of the overlap part is narrower than that of the non-overlap part.…”

Section: 42mentioning

confidence: 99%

Design and fabrication of MEMS optical switches

Li¹

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This thesis focuses on the research related to the microelectromechanical systems (MEMS) optical switch consisting of three major areas, micromahined actuator, deep reactive ion etching (DRIE) fabrication, and total internal reflection (TIR) optical switch.Firstly, a stable micromachined actuator with large displacement has been designed and demonstrated. It consists of comb-finger-sets and compliant microstructure to amplify the displacement efficiently and lock the output by bifurcation effect. The amplification obtained is 54.2 when the input displacement is only 0.96 um and it is locked thereafter.Subsequently, a DRIE fabrication process for silicon on insulator (SOI) wafers has been investigated. Based on the study of DRIE process chemically and physically, the notching effect on SOI substrate is eliminated and utilized to realize dry release resolving the station problem by developing a spacer oxide thin film technique.Lastly, a TIR prism optical switch based on the thermo-optic (TO) effect has been studied. It takes the merits of robustness of thermo-optic prism and the precise control and batch fabrication of MEMS. The optical properties including insertion loss, polarization dependent loss and cross-talk are theoretically simulated and proven by experiments.ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library It is a pleasure to offer thanks to those who made this dissertation possible and made my stay in NTU most meaningful and enjoyable. ii ATTENTION: The Singapore Copyright Act applies to the use of this document. Nanyang Technological University Library 3.3.1 DRIE fabrication 51 3.3.2 Displacement measurement and discussions 53 3.3.3 Resonant frequency measurement and discussion 55 3.4 FABRICATION TOLERANCE ANALYSIS 57 3.4.1 The effect of the beam profile 59 3.4.2 The effect of a comb finger uneven depth 64 3.4.3 Effect of undercut of microbeams 67 3.5 SUMMARY 70 CHAPTER FOUR THE DEEP RIE PROCESS 73 4.1 DRIE FABRICATION PROCESS FLOW 75 4.2 CHEMISTRY-PHYSICS OF DRIE 77 4.2.1 Effect of platen power 80 4.2.2 Effect of gas flow with source power 83 4.2.3 The effect of the duration of the cyclic etch/passivation cycles 86 4.2.4 Effect of process pressure 87 4.3 THE LOADING EFFECT 89 4.3.1 The loading effect dependence on the design of various features. 89 4.3.2 Etch rate along the process 98 4.3.3 Beam verticality 100 4.4 THE NOTCHING EFFECT 101 4.4.

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Section: 42mentioning

confidence: 99%

Design and fabrication of MEMS optical switches

Li¹

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Bosch etching for the creation of a 3D nanoelectroporation system for high throughput gene delivery

Bertani

Chang

et al. 2015

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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In order to create a high-throughput electroporation based cell transfection system, it is required that each cell has localized delivery and minimal membrane damage to ensure optimal transfection and longevity post-biomolecule delivery. To meet these requirements, a three-dimensional (3D) nanochannel device was fabricated on a Si platform due its ease of etching, wide industrial availability, and mechanical stability. The device is designed to shoot desired biomolecules into a seated array of target cells to achieve the high-throughput of bulk electroporation, but with greatly reduced cell mortality. To accomplish this, a wafer-scale Bosch etching process was optimized to etch a 3D array of channels consisting of larger microchannels feeding into smaller nanochannels that cells are ultimately seated on for transfection. The microchannel array consists of 50 μm wells spaced 50 μm apart, which are etched from the “back side.” The wafer is then flipped over to etch the smaller 650 nm channels on the “front side.” In the creation of the 3D silicon device, other feature sizes were explored, and their Bosch etching was characterized for comparison. The results show that when etching samples with the same feature sizes, but different densities, there was no relation between feature density and etch rate for our recipe. However, when etching features, or more specifically, circular channels of different sizes (650 nm–150 μm), the results show a positive correlation with etch rate (1.10–4.06 μm/min). Standard deviations indicate very uniform etching with an average value of 0.1 μm/min across all etches. After optimization, the 3D Si device was tested to ensure successful cell seating and transfection via electroporation, using fluorescence as the tool of evaluation. Fluorescent imaging (postelectroporation) indicates a transfection efficiency of approximately 70% with a cell viability of roughly 90%.

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Investigation of Loading Effect in Deep Trench Lisa Technology

Cited by 2 publications

References 2 publications

Design and fabrication of MEMS optical switches

Design and fabrication of MEMS optical switches

Bosch etching for the creation of a 3D nanoelectroporation system for high throughput gene delivery

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