TY - JOUR
T1 - Working distance comparison of inductive and electromagnetic couplings for wireless and passive underwater monitoring system of rinsing process in semiconductor facilities
AU - Zhang, Xu
AU - Chae, Junseok
N1 - Funding Information:
Manuscript received December 16, 2010; revised February 17, 2011; accepted April 14, 2011. Date of publication May 05, 2011; date of current version October 26, 2011. This work was partially supported through Connection One, NSF I/UCRC at Arizona State University. The associate editor coordinating the review of this paper and approving it for publication was Dr. Larry Nagahara.
PY - 2011
Y1 - 2011
N2 - 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.
AB - 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.
KW - Electromagnetic (EM) coupling
KW - inductive coupling
KW - passive sensing
KW - underwater sensing
KW - wireless sensing
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U2 - 10.1109/JSEN.2011.2151185
DO - 10.1109/JSEN.2011.2151185
M3 - Article
AN - SCOPUS:80055028062
SN - 1530-437X
VL - 11
SP - 2932
EP - 2939
JO - IEEE Sensors Journal
JF - IEEE Sensors Journal
IS - 11
M1 - 5763744
ER -