Real-time monitoring of acetic acid and PGMEA in a photolithographic multifunction chemical filter using a laser-based multi-species VOC analyzer

Charlotte Pouligny; Vivien Carlini; Laura McHale; Chris W. Rella; Kai M. Skog; Fabin Shakila; Ambre Steiner; Thomas Vitrani

doi:10.1117/12.2614119

26 May 2022 Real-time monitoring of acetic acid and PGMEA in a photolithographic multifunction chemical filter using a laser-based multi-species VOC analyzer

Charlotte Pouligny, Vivien Carlini, Laura McHale, Chris W. Rella, Kai M. Skog, Fabin Shakila, Ambre Steiner, Thomas Vitrani

Author Affiliations +

Proceedings Volume 12053, Metrology, Inspection, and Process Control XXXVI; 1205321 (2022) https://doi.org/10.1117/12.2614119
Event: SPIE Advanced Lithography + Patterning, 2022, San Jose, California, United States

Conference Poster

Abstract

It has long been understood1 that in photolithographic mini-environments, acetic acid reacts with residual ammonia to form salts that cause haze formation on the scanner optics. It also induces cosmetic defects (satellite defect) on the surface of the photoresist. The acetic acid is generated in multi-function chemical filters, where PGMEA (a photoresist solvent) undergoes hydrolysis in the acidified media used to remove bases, producing PGME and acetic acid. Acetic acid is difficult to measure in the gas phase at parts-per-billion levels, requiring either costly and cumbersome mass spectrometers that are unsuitable for deployment in a production environment, or ion chromatography, a labor-intensive, off-line technique commonly performed off-site by a third-party analytical services lab. In this manuscript, we report on a novel AMC monitoring solution for measuring acetic acid, PGMEA, PGME, NH3, and other VOCs (volatile organic compounds). The heart of the system is a real-time laser-based analyzer based on a new analytical technique called Broad Band Cavity Ring Down Spectroscopy (BB-CRDS). The VOC monitoring system has several features which make it well-suited to AMC measurements in the production environment: ultra-trace measurements of a variety of VOC species; 24/7 operation without user intervention; little to no consumables; unparalleled accuracy without the need for calibration. The AMC system also consists of a high performance 8-port multiplexer, monitoring the photolithography bay at STMicroelectronics - Rousset fab. Here we report on acetic acid and PGMEA levels observed in several track tool and scanner minienvironments, over a period of several months.

Citation Download Citation

Charlotte Pouligny, Vivien Carlini, Laura McHale, Chris W. Rella, Kai M. Skog, Fabin Shakila, Ambre Steiner, and Thomas Vitrani "Real-time monitoring of acetic acid and PGMEA in a photolithographic multifunction chemical filter using a laser-based multi-species VOC analyzer", Proc. SPIE 12053, Metrology, Inspection, and Process Control XXXVI, 1205321 (26 May 2022); https://doi.org/10.1117/12.2614119

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available