Fabrication of a miniaturized ionization gas sensor with polyimide spacer

Walewyns, Thomas; Scheen, Gilles; Tooten, Ester; Fissi, Lamia El; Dupuis, Pascal; Francis, Laurent

doi:10.1117/12.886759

Cited by 7 publications

(5 citation statements)

References 15 publications

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“…Moreover, depending on its formulation, PI can be spin-coated with thicknesses as high as several tens of μm and as low as 200 nm by diluting the precursor solution in its solvant [8]. A large range of possible gaps is thus allowed between a top movable clamped-clamped membrane or beam and a fixed bottom electrode lying on the substrate.…”

mentioning

confidence: 99%

Poling Field Dependence of Longitudinal and Transverse Wave Velocities, Young's Modulus, and Poisson's Ratio in Piezoelectric Ceramics

Ogawa¹,

Ishii²,

Matsumoto³

et al. 2012

Jpn. J. Appl. Phys.

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The interest of using polyimide as a sacrificial and anchoring layer is demonstrated for post-processing surface micromachining and for the incorporation of metallic nanowires into microsystems. In addition to properties like a high planarization factor, a good resistance to most non-oxidizing acids and bases, and CMOS compatibility, polyimide can also be used as a mold for nanostructures after ion track-etching. Moreover, specific polyimide grades, such as PI-2611 from HD Microsystems TM , involve a thermal expansion coefficient similar to silicon and low internal stress. The process developed in this study permits higher gaps compared to the state-of-the-art, limits stiction problems with the substrate and is adapted to various top-layer materials. Most metals, semiconductors or ceramics will not be affected by the oxygen plasma required for polyimide etching. Released structures with vertical gaps from one to several tens of μm have been obtained, possibly using multiple layers of polyimide. Furthermore, patterned freestanding nanowires have been synthesized with diameters from 20 to 60 nm and up to 3 μm in length. These results have been applied to the fabrication of two specific devices: a generic nanomechanical testing lab-on-chip platform and a miniaturized ionization sensor.(Some figures may appear in colour only in the online journal) Polyimide (PI) is often selected for its high planarization factor, CMOS compatibility, tolerance to most chemical products used in microfabrication, and chemical resistance up to high temperatures. Moreover, depending on its formulation, PI can be spin-coated with thicknesses as high as several tens of μm and as low as 200 nm by diluting the precursor solution in its solvant [8]. A large range of possible gaps is thus allowed between a top movable clamped-clamped membrane or beam and a fixed bottom electrode lying on the substrate. New formulations of PI show additional interesting properties such as a thermal expansion coefficient similar to silicon (Si),

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mentioning

confidence: 99%

Poling Field Dependence of Longitudinal and Transverse Wave Velocities, Young's Modulus, and Poisson's Ratio in Piezoelectric Ceramics

Ogawa¹,

Ishii²,

Matsumoto³

et al. 2012

Jpn. J. Appl. Phys.

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“…The partially cured PI showed different etch rate behaviour compared to fully cured PI that is commonly used in microfluidic devices. The initial etching parameters to etch the partially cured PI were taken from previously reported work [12,16,17], where a detailed study had been done to achieve higher etch rates in fully cured PI using a mixture of oxygen and fluorine based gases in the plasma with minimum under etch. The technique was optimized here for partially cured PI followed by characterization of the etch rate by changing parameters such as gases, power applied and pressure in the chamber.…”

Section: Discussionmentioning

confidence: 99%

“…The optimization of the etching parameters for PI in the RIE and ICP systems was done by changing the pressure, RF power, gas flows and gas mixture (O 2 and Ar, and O 2 and CF 4 / SF 6 ) in the chamber. The starting parameters were chosen as previously described in [12,16,17]. The etching of PI with Si 3 N 4 mask was only done with O 2 and Ar mixture whereas etching with Al mask was done with O 2 and CF 4 /SF 6 mixture.…”

Section: Etching Of Pimentioning

confidence: 99%

Fabrication of polyimide based microfluidic channels for biosensor devices

Zulfiqar

Pfreundt

Svendsen

et al. 2015

J. Micromech. Microeng.

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The ever-increasing complexity of the fabrication process of Point-of-care (POC) devices, due to high demand of functional versatility, compact size and ease-of-use, emphasizes the need of multifunctional materials that can be used to simplify this process. Polymers, currently in use for the fabrication of the often needed microfluidic channels, have limitations in terms of their physicochemical properties. Therefore, the use of a multipurpose biocompatible material with better resistance to the chemical, thermal and electrical environment, along with capability of forming closed channel microfluidics is inevitable. This paper demonstrates a novel technique of fabricating microfluidic devices using polyimide (PI) which fulfills the aforementioned properties criteria. A fabrication process to pattern microfluidic channels, using partially cured PI, has been developed by using a dry etching method. The etching parameters are optimized and compared to those used for fully cured PI. Moreover, the formation of closed microfluidic channel on wafer level by bonding two partially cured PI layers or a partially cured PI to glass with high bond strength has been demonstrated. The reproducibility in uniformity of PI is also compared to the most commonly used SU8 polymer, which is a near UV sensitive epoxy resin. The potential applications of PI processing are POC and biosensor devices integrated with microelectronics.

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“…The use of polyimide as sacrificial layer is foreseen as an efficient generic solution to study a wide variety of thin films. 46 The main advantage of the present technique lies in that all test structures (i.e., specimens and actuators) are built up on-chip. No external device, such as a nano-indenter or a tensometer testing platform, is needed.…”

Section: Discussionmentioning

confidence: 99%

On-chip stress relaxation testing method for freestanding thin film materials

Coulombier

Guisbiers

Vayrette

et al. 2012

Review of Scientific Instruments

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A stress relaxation method for freestanding thin films is developed based on an on-chip internal stress actuated microtensile testing set-up. The on-chip test structures are produced using microfabrication techniques involving cleaning, deposition, lithography, and release. After release from the substrate, the test specimens are subjected to uniaxial tension. The applied load decays with the deformation taking place during relaxation. This technique is adapted to strain rates lower than 10(-6)∕s and permits the determination of the strain rate sensitivity of very thin films. The main advantage of the technique is that the relaxation tests are simultaneously performed on thousands of specimens, pre-deformed up to different strain levels, for very long periods of time without monopolizing any external mechanical loading equipment. Proof of concept results are provided for 205-nm-thick sputtered AlSi(0.01) films and for 350-nm-thick evaporated Pd films showing unexpectedly high relaxation at room temperature.

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Fabrication of a miniaturized ionization gas sensor with polyimide spacer

Cited by 7 publications

References 15 publications

Poling Field Dependence of Longitudinal and Transverse Wave Velocities, Young's Modulus, and Poisson's Ratio in Piezoelectric Ceramics

Poling Field Dependence of Longitudinal and Transverse Wave Velocities, Young's Modulus, and Poisson's Ratio in Piezoelectric Ceramics

Fabrication of polyimide based microfluidic channels for biosensor devices

On-chip stress relaxation testing method for freestanding thin film materials

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