A micromachined flow shear-stress sensor based on thermal transfer principles

Liu, Chang; Huang, Jin-Biao; Zhu, Zhenjun; Jiang, Feifei; Tung, Steve; Tai, Yu‐Chong; Ho, Chih‐Ming

doi:10.1109/84.749408

Cited by 148 publications

(20 citation statements)

References 20 publications

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“…The principles of micro thermal shear stress sensor [7,8] are briefly described below. The sensor consists of a thermal sensor element located on the surface of a diaphragm.…”

Section: Principlesmentioning

confidence: 99%

Micro thermal shear stress sensor based on vacuum anodic bonding and bulk-micromachining

Liang

Shi

et al. 2008

Chinese Phys. B

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This paper describes a micro thermal shear stress sensor with a cavity underneath, based on vacuum anodic bonding and bulk micromachined technology. A Ti/Pt alloy strip, 2μm × 100μm, is deposited on the top of a thin silicon nitride diaphragm and functioned as the thermal sensor element. By using vacuum anodic bonding and bulk-si anisotropic wet etching process instead of the sacrificial-layer technique, a cavity, functioned as the adiabatic vacuum chamber, 200μm × 200μm × 400μm, is placed between the silicon nitride diaphragm and glass (Corning 7740). This method totally avoid adhesion problem which is a major issue of the sacrificial-layer technique.

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“…The principles of micro thermal shear stress sensor [7,8] are briefly described below. The sensor consists of a thermal sensor element located on the surface of a diaphragm.…”

Section: Principlesmentioning

confidence: 99%

Micro thermal shear stress sensor based on vacuum anodic bonding and bulk-micromachining

Liang

Shi

et al. 2008

Chinese Phys. B

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“…The shear stress is in direct proportion to the viscosity of the etchant and the flow velocity grads. [8] The shear stress distribution driven from the flow velocity grads is simulated as shown in Fig. 5, from which the maximum shear stress is 5.3×10 4 Pa.…”

Section: Swirling Of the Heating-induced Etchantmentioning

confidence: 99%

A novel anti-shock silicon etching apparatus for solving diaphragm release problems

Shi

Chen

et al. 2010

Chinese Phys. B

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This paper presents a novel anti-shock bulk silicon etching apparatus for solving a universal problem which occurs when releasing the diaphragm (e.g. SiNx), that the diaphragm tends to be probably cracked by the impact of heatinginduced bubbles, the swirling of heating-induced etchant, dithering of the hand and imbalanced etchant pressure during the wafer being taken out. Through finite element methods, the causes of the diaphragm cracking are analysed. The impact of heating-induced bubbles could be the main factor which results in the failure stress of the SiNx diaphragm and the rupture of it. In order to reduce the four potential effects on the cracking of the released diaphragm, an anti-shock bulk silicon etching apparatus is proposed for using during the last etching process of the diaphragm release. That is, the silicon wafer is first put into the regular constant temperature etching apparatus or ultrasonic plus, and when the residual bulk silicon to be etched reaches near the interface of the silicon and SiNx diaphragm, within a distance of 50-80 µm (the exact value is determined by the thickness, surface area and intensity of the released diaphragm), the wafer is taken out carefully and put into the said anti-shock silicon etching apparatus. The wafer's position is at the geometrical centre, also the centre of gravity of the etching vessel. An etchant outlet is built at the bottom. The wafer is etched continuously, and at the same time the etchant flows out of the vessel. Optionally, two symmetrically placed low-power heating resistors are put in the anti-shock silicon etching apparatus to quicken the etching process. The heating resistors' power should be low enough to avoid the swirling of the heating-induced etchant and the impact of the heating-induced bubbles on the released diaphragm. According to the experimental results, the released SiNx diaphragm thus treated is unbroken, which proves the practicality of the said anti-shock bulk silicon etching apparatus.

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“…During the past two decades, a variety of micro-electromechanical systems (MEMS) have been fabricated through the rapid development of precision and ultra-precision machining technologies. Liu et al (1999) described two microthermal shear-stress sensors, in which high aspect ratio cavities of (200 × 250) µm (2) × 400 µm were fabricated using bulk silicon substrate etching and anodic bonding technology [1]. Alshehri et al (2013) developed micro hot-film shear-stress sensors using surface micromachining techniques and fabricated a micro silicon-nitride diaphragm and polycrystalline silicon heat-sensing element [2].…”

Section: Introductionmentioning

confidence: 99%

“…The size precision of a leaf springs mainly affects the probe's stiffness and isotropy. According to the Equation (1) or Equation (2) in Reference [3], we can obtain that the relative change of the stiffness or anisotropy is less than 0.5% when the four V-shaped leaf spring's width have an error of 10 µm. Therefore, the target manufacturing accuracy of a leaf springs can be controlled in ±10 µm.…”

Section: Introductionmentioning

confidence: 99%

Precision Manufacturing of Patterned Beryllium Bronze Leaf Springs via Chemical Etching

Wang

et al. 2018

Applied Sciences

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Patterned leaf springs made of a beryllium bronze sheet are the key components of certain micro/nano contact probes. The accuracy of the probe is determined based on the precision of the formed pattern. However, a traditional manufacturing method using wire-electrode discharge machining (wire-EDM) is subject to poor tolerance at the sharp edges and corners. In addition, high energy consumption and costs are incurred for complex patterns. This paper presents a new chemical etching method for the manufacturing of a patterned leaf spring with high precision. Both the principle and process are introduced. Taguchi experiments were designed and conducted and the optimal process parameters were obtained based on the mean value and a variance analysis. Four V-shaped and some other complex patterned leaf springs were successfully fabricated. Comparison experiments concerning the characteristic parameters of the leaf spring were also conducted. The experimental results reveal that the patterned leaf springs manufactured through this method are much better than those achieved using wire-EDM. This manufacturing method can be used to fabricate different high-precision patterned leaf springs or membranes for coordinate measuring machines (CMM) probes and other measuring equipment.

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A micromachined flow shear-stress sensor based on thermal transfer principles

Cited by 148 publications

References 20 publications

Micro thermal shear stress sensor based on vacuum anodic bonding and bulk-micromachining

Micro thermal shear stress sensor based on vacuum anodic bonding and bulk-micromachining

A novel anti-shock silicon etching apparatus for solving diaphragm release problems

Precision Manufacturing of Patterned Beryllium Bronze Leaf Springs via Chemical Etching

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