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Papers by Shih-Chia Chang

Sensors and Actuators A: Physical, 2002

Two lift-off methods were developed for patterning platinum ®lms deposited at 400 8C via DC magne... more Two lift-off methods were developed for patterning platinum ®lms deposited at 400 8C via DC magnetron sputtering. Both methods are based upon the formation of multiple-layer metal lithography masks. Ti/Al and Cr/Al masks were fabricated such that the Ti or Cr layer overhangs the aluminum base layer. When using a Ti/Al lithography mask, the patterned platinum lines were broadened and the line resolution was low. Higher line resolution and cleaner line edges were obtained when a Cr/Al mask was used.

Proceedings of the International Solid-State Sensors and Actuators Conference - TRANSDUCERS '95

Polyimide, polymethylmethacrylate (PMMA) and polyester-based polymers were investigated as potent... more Polyimide, polymethylmethacrylate (PMMA) and polyester-based polymers were investigated as potential electroplating mold materials. They showed high tensile stress (/spl equiv/10/sup 8/ dyne/cm/sup 2/) after heat treatment at temperatures /spl ges/ 200/spl deg/C. Conventional reactive ion etching techniques together with a trilevel masking scheme was used to delineate the polymer layers. The etch mask used was either spin-on glass or aluminum, and the etch gas was oxygen. With proper power density and etch gas pressure, aspect ratios >5 were obtained. Compatibility issues between RIE and the etch mask materials, as well as between RIE and the plating base materials are discussed.

Journal of Microelectromechanical Systems, 2002

The addition of an arc suppression circuit to a microrelay (made by micromachining technology) mi... more The addition of an arc suppression circuit to a microrelay (made by micromachining technology) minimizes arcing during switching and results in an increase in the relay service life. To demonstrate the concept and benefits of the integrated relay, an arc suppression circuit was designed and built with off-the-shelf components. In the demonstration, the microrelay was connected to a power transistor

Journal of Micromechanics and Microengineering, 1991

Silicon-based microbridges have been integral parts in a variety of silicon sensors. The authors ... more Silicon-based microbridges have been integral parts in a variety of silicon sensors. The authors have studied bridge formation techniques on (100)-oriented silicon wafers using the orientation-dependent etching characteristics of ethylene diamine-pyrocatechol (EDP) and potassium hydroxide (KOH). Specific items investigated were the dependence of the bridge undercutting on bridge orientation and the effects of the masking material-which usually constitutes, either wholly

Journal of Electronic Materials, 1984

The conventional method used for aluminum (Al) and aluminum alloy (Al + Si, Al + Si + Cu) delinea... more The conventional method used for aluminum (Al) and aluminum alloy (Al + Si, Al + Si + Cu) delineation in integrated circuits is mainly by wet chemical etching. Because of its isotropic characteristic, wet chemical etching becomes inadequate for patterning Al metal lines with linewidths narrower than about 4 Μm. In this work, Al and Al alloys (Al + 2% Si; Al + 1% Si + 1% Cu) were reactively etched in SiCl4 plasma using patterned photoresist as the etch-mask. Resist patterns were generated either by conventional processing methods or by tri-level resist techniques which included hard-baking (200°C, ≤ 30 min), and two consecutive reactive ion etchings in CF4 and 02 plasmas. Masking resists prepared by the tri-level resist technique retained their integrity during exposure to a SiCl4 plasma, and significantly improved resolution and fidelity of pattern transfer from resist to underlying Al or Al alloy film. The substrate surface of the reactively etched Al + Si + Cu sample was considerably rougher than that of the Al or Al + Si sample due to the high concentration of Cu accumulated at the metal/substrate region during RIE process.

Tin oxide based microsensors with integrated polysilicon heaters were fabricated on thin silicon ... more Tin oxide based microsensors with integrated polysilicon heaters were fabricated on thin silicon membranes generated by anisotropic wet chemical etching using ethylene diamine pyrocatechol as the etchant. Good thermal isolation and lower power consumption were achieved. The sensing elements, tin oxide thin films, were prepared either by sputter deposition or by metallo-organic deposition. The completed microsensors showed good response to

Sensors and Actuators, 1989

Electron Devices, IEEE Transactions on, 1979

Absstract-A thin-film semiconductor NO, sensor has been fabricated by reactive RF sputtering from... more Absstract-A thin-film semiconductor NO, sensor has been fabricated by reactive RF sputtering from a tin target. The gas detection is based on monitoring the sensor resistance change caused by NO, chemisorption on the sensor surface. The sensor is highly sensitive and selective toward detecting NO, in ai r. The chemical composition of the film was investigated by AES and ESCA. A simple chemisorption model is presented to explain the observed phenomena.

IEEE Technical Digest on Solid-State Sensor and Actuator Workshop, 1988

A comparative study was done between ethylene diamine-pyrocatechol (EDP) and potassium hydroxide ... more A comparative study was done between ethylene diamine-pyrocatechol (EDP) and potassium hydroxide (KOH) etching systems for micromachining mesas in (100)-oriented silicon wafers, A street corner compensation scheme was used to fabricate a perfect mesa, using KOH as the etchant. This perfect mesa structure is attributed to the relative etch rates of KOH for the three major crystal planes which are,