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Interfacial Structure of Photoresist Thin Films in Developer Solutions



Vivek M. Prabhu, B D. Vogt, Wen-Li Wu, Jack F. Douglas, Sushil K. Satija, D M. Goldfarb, H Ito


The development step is critical to the fabrication of nanostructures in chemically amplified photoresist technology. With critical dimensions (CD) shrinking to sub-100 nm and the concurrent reduction in exposure radiation wavelength, line-edge roughness (LER) is becoming more important to control. One method is to identify the contributions to LER from the development step, which requires an improved framework. The aqueous base tetramethylammonium hydroxide (TMAH) is typically used to selectively dissolve radiation-exposed photoresist by shifting the chemical equilibrium from the un-ionized to ionized form. This ionization is responsible for both observed thin film swelling and dissolution. The mechanism of dissolution and correlation to the final surface roughness remains a technical challenge.We present a method to measure the aqueous base profile and resulting thin film swelling by zero-average contrast immersion neutron reflectivity. This method quantifies the total film swelling, complemented by a quartz crystal microbalance technique, but also provides the base profile and dependence on TMAH concentration within sub-100 nm films. These experiments provide data that can be incorporated into future models for dissolution and LER.
Proceedings Title
Proceedings of SPIE
Conference Dates
February 28-March 4, 2005
Conference Location
San Jose, CA
Conference Title
SPIE Advanced Lithography


dissolution, interface, line-edge roughness, lithography, neutron reflectivity, photoresist, swelling


Prabhu, V. , Vogt, B. , Wu, W. , Douglas, J. , Satija, S. , Goldfarb, D. and Ito, H. (2005), Interfacial Structure of Photoresist Thin Films in Developer Solutions, Proceedings of SPIE, San Jose, CA, [online], (Accessed May 26, 2024)


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Created March 1, 2005, Updated February 19, 2017