DocumentCode :
3561062
Title :
Working Distance Comparison of Inductive and Electromagnetic Couplings for Wireless and Passive Underwater Monitoring System of Rinsing Process in Semiconductor Facilities
Author :
Zhang, Xu ; Chae, Junseok
Author_Institution :
Sch. of Electr. Comput. & Energy Eng., Arizona State Univ., Tempe, AZ, USA
Volume :
11
Issue :
11
fYear :
2011
Firstpage :
2932
Lastpage :
2939
Abstract :
This paper reports a side-by-side comparison of two wireless and passive sensing systems: inductive and electromagnetic (EM) couplings for an application of in-situ and real-time monitoring of wafer cleanliness in the rinsing process at semiconductor/microelectromechanical system (MEMS) manufacturing facilities. A MEMS sensor is designed to measure the resistivity of water, corresponding to the ionic concentration, to evaluate the rinsing process inside the micro-features. The transponder, containing the MEMS sensor, receives power from an external interrogator, modulates the resistivity data, and emits back the modulated signal to the interrogator, in all wireless and battery-free operation. Two wireless systems based on inductive and EM couplings have been implemented on 4-inch glass wafers, maintaining the wafer form factor. Inductive coupling system has parasitic electric field coupling. The working distance of the inductive coupling system is attenuated in water and is likely limited by signal-to-noise ratio (SNR), while that of the EM coupling is primarily limited by the coupled power. Hence, inductive coupling is suitable for a short distance measurement that allows more sophisticated functionality with sufficient power, whereas EM coupling could be optimized for long distance detection but has a tight power budget. The implemented on-wafer wireless monitoring units achieve a working distance of 6 and 25 cm with a concentration resolution of less than 2% (4 ppb for a 200 ppb solution) for inductive and EM couplings, respectively.
Keywords :
acoustic transducers; distance measurement; electric fields; electromagnetic coupling; microsensors; production facilities; semiconductor device manufacture; semiconductor industry; EM coupling; MEMS manufacturing facility; MEMS sensor; SNR; distance 25 cm; distance 6 cm; electromagnetic coupling; glass wafer form factor; inductive coupling system; ionic concentration; long distance detection; on-wafer wireless monitoring unit; parasitic electric field coupling; passive sensing system; rinsing process; semiconductor-microelectromechanical system manufacturing facility; short distance measurement; signal-to-noise ratio; size 4 in; underwater passive monitoring system; wafer cleanliness monitoring; water resistivity data; wireless sensing system; wireless underwater monitoring system; working distance comparison; Couplings; Inductors; Rectifiers; Signal to noise ratio; Transponders; Wireless communication; Wireless sensor networks; Electromagnetic (EM) coupling; inductive coupling; passive sensing; underwater sensing; wireless sensing;
fLanguage :
English
Journal_Title :
Sensors Journal, IEEE
Publisher :
ieee
Conference_Location :
5/5/2011 12:00:00 AM
ISSN :
1530-437X
Type :
jour
DOI :
10.1109/JSEN.2011.2151185
Filename :
5763744
Link To Document :
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