Optimizing Parylene C Adhesion for MEMS Processes: Potassium Hydroxide Wet Etching

Charmet, Jérôme; Bitterli, Joanna; Sereda, Olha; Liley, Martha; Renaud, Philippe; Keppner, H.

doi:10.1109/jmems.2013.2248126

Cited by 30 publications

(17 citation statements)

References 34 publications

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“…There was a choice between two common methods for evaluating the adhesive strength between Parylene C and each substrate, scarification [14] and measuring tensile strength [15]. In this study the tensile method was used.…”

Section: Measurement and Optimization Of Adhesive Strength Between Pamentioning

confidence: 99%

Characterization of Parylene C as protective layer on micro-piezoelectric printheads

Yin

Zou

et al. 2015

Materials Science in Semiconductor Processing

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Section: Measurement and Optimization Of Adhesive Strength Between Pamentioning

confidence: 99%

Characterization of Parylene C as protective layer on micro-piezoelectric printheads

Yin

Zou

et al. 2015

Materials Science in Semiconductor Processing

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“…Due to its low relative permittivity, high resistivity, biocompatibility and conformal deposition, Parylene is suitable as an electrical isolation material for implantable devices. Adhesion of Parylene to inorganic substrates can be improved by adhesion promoter and thermal treatment [27]. However, Parylene has relatively high water vapor transmission rate (WVTR) compared to many dielectric materials [26,28], therefore Parylene by itself is not sufficient to protect implanted ICs.…”

Section: Introductionmentioning

confidence: 99%

SiC protective coating for photovoltaic retinal prosthesis

et al. 2016

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Objective To evaluate PECVD SiC as a protective coating for retinal prostheses and other implantable devices, and to study their failure mechanisms in vivo. Approach Retinal prostheses were implanted in rats subretinally for up to 1 year. Degradation of implants was characterized by optical and scanning electron microscopy. Dissolution rates of SiC, SiNx and thermal SiO2 were measured in accelerated soaking tests in saline at 87°C. Defects in SiC films were revealed and analyzed by selectively removing the materials underneath those defects. Main results At 87°C SiNx dissolved at 18.3±0.3nm/day, while SiO2 grown at high temperature (1000°C) dissolved at 1.04±0.08A/day. SiC films demonstrated the best stability, with no quantifiable change after 112 days. Defects in thin SiC films appeared primarily over complicated topography and rough surfaces. Significance SiC coatings demonstrating no erosion in accelerated aging test for 112 days at 87°C, equivalent to about 10 years in vivo, can offer effective protection of the implants. Photovoltaic retinal prostheses with PECVD SiC coatings exhibited effective protection from erosion during the 4-month follow-up in vivo. The optimal thickness of SiC layers is about 560nm, as defined by anti-reflective properties and by sufficient coverage to eliminate defects.

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“…Thin films can bond to underlying substrates physically by filling in pores or surface topography, through covalent bonds, or by van der Waals forces. In addition, interfaces that typically have poor adhesion, such as Parylene deposited on silicone, can be improved with adhesion promoters, such as the silane A-174, which bonds covalently both with Parylene free radicals during the deposition process and provide a strong linkage with the underlying substrate (Charmet et al, 2013). Also, a combination of heat and compression can bond Parylene layers together by causing the polymer chains on the surface of the touching films to become entangled (Noha et al, 2004).…”

Section: Peel Test Device Designmentioning

confidence: 99%

Mechanical Properties of Thin-Film Parylene–Metal–Parylene Devices

Lee

Meng

2015

Front. Mech. Eng.

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Structures and testing methods for measuring the adhesion strength, minimum bending diameter, and bending fatigue performance of thin-film polymer electronic architectures were developed and applied to Parylene-metal-Parylene systems with and without the moisture barrier Al2O3 [deposited using atomic layer deposition (ALD)]. Parylene-metalParylene interfaces had the strongest average peel test strength and Parylene-Parylene interfaces had the weakest peel test strength. Layers of ALD Al2O3 deposited within the device increased the average peel strength for Parylene-Parylene interfaces when combined with silane A-174, but did not increase that of the Parylene-metal-Parylene interface. Metal traces in the middle of 24 μm thick Parylene-metal-Parylene devices had a minimum bending diameter of ~130 μm before breaking and being measured as an open circuit. The addition of one layer of Al2O3 above the traces allowed them to be completely creased when bent away from the Al2O3 layer without producing an open circuit, but increased the minimum bending diameter to ~450 μm when bent towards the Al2O3. Although fatigue testing produced cracks in all devices after 100k bends, the insulation of the Parylene-metal-Parylene devices without Al2O3 performed well with electrochemical impedance spectroscopy showing only small decreases in impedance magnitude and small increases of impedance phase at low frequencies. However, devices with Al2O3 failed during EIS due to Al2O3 being deteriorated by water.

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Optimizing Parylene C Adhesion for MEMS Processes: Potassium Hydroxide Wet Etching

Cited by 30 publications

References 34 publications

Characterization of Parylene C as protective layer on micro-piezoelectric printheads

Characterization of Parylene C as protective layer on micro-piezoelectric printheads

SiC protective coating for photovoltaic retinal prosthesis

Mechanical Properties of Thin-Film Parylene–Metal–Parylene Devices

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