In situ and real-time metrology during rinsing of micro- and nano-structures

• Published in: Microelectronic engineering Vol. 86; no. 2; pp. 199 - 205
• Main Authors: Yan, Jun, Dhane, Kedar, Vermeire, Bert, Shadman, Farhang
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2009; Elsevier
• Subjects: Cleaning; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Metrology; Physics; Rinse model; Sensor; Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing; Wafer rinsing; Water usage; Metrology; Rinse model; Wafer rinsing; Cleaning; Water usage; Sensor; Chemical sensors; Surface charge; In situ; Measurement sensor; Measuring methods; Time measurement; Charge transport; Nanostructures; Surface effect; Case study; Fine structure; Residual impurity; Wafers; Transport processes
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2008.10.014

A new technology, called electro-chemical residue sensor (ECRS), has been developed for the in situ and real-time measurement of the residual impurities left on the wafer surface and in the fine structures of patterned wafers during typical rinse processes. The key components of this technology, which consist of the sensor hardware and a process model, are described. The testing results of the ECRS show that the residual impurity concentration is significantly different from what is typically provided by the bulk water resistivity, which is usually employed for determining the progress of the rinse. As a case study, the new metrology method has been applied to the removal of sulfate ions from patterned wafers; the importance of various surface interactions, charge effects, and transport processes is determined. Two examples of the use of the ECRS for the development of novel rinse recipes to reduce water usage are also discussed.