Development of a Method for Resist Removal by Ozone with Acetic Acid Vapor

Abstract

A method of removing the photoresist using ozone gas with acetic acid vapor has been developed. Glass substrates ͑size 100 ϫ 100 mm 2 ͒ coated with I-line resist were treated under the conditions of substrate temperature, (T S ) 27-50°C; acetic acid vapor, 2-18 vol %; ozone, 0-9.3 vol % ͑0-200 g/m 3 ͒; total gas flow rate, 2 L/min; and gas pressure, 100 kPa. A previous ozone treatment with oversaturated water vapor or sprayed water overcame the limitation of ozone diffusion into the resist by the control of the water film on the resist. In this study, pure acetic acid vapor has been first applied for the resist removal by ozone in order to improve the oxidation rate of the resist, because acetic acid is an inactive solvent in the ozonization, and the solubility of ozone is much higher than water. It was observed that the resist removal rate increased with acetic acid and ozone concentration, and reached at 6 m/min at T S ϭ 50°C, which was about six times greater than that of the previous ozone treatment. Metal corrosion of molybdenum and aluminum electrodes was found negligible during the ozone treatment with acetic acid vapor. The mechanism of resist removal without the metal corrosion by ozone with acetic acid vapor is also discussed, based on the solubility of ozone in acetic acid and the corrosion current in ozonized solutions.

Effect of Microbubbles on Ozonized Water for Photoresist Removal

“…As a result, large amounts of chemicals, such as H 2 SO 4 , H 2 O 2 , HCl, NH 4 OH, and amine solvents, are required in wet cleaning processes [6,7]. For safety and environmental reasons, the use of ozonized water is attracting attention as a viable method for removing organic contaminants, which has been conventionally removed by a high temperature sulfuric acid -hydrogen peroxide mixture (SPM) [8,9]. In terms of applications to semiconductor manufacturing, ozonized water cleaning systems are strongly desired as they provide enhanced removal rates for organic contaminants.…”

Effects of Oxygen Microbubbles on Photoresist Layers under Hot Water Conditions

“…As the samples for the present experimental study, high-dose ion-implanted photoresists were used as one of the most challengeable targets in the semiconductor manufacturing [7,8]. Silicon wafers spin-coated with a high-resolution positive type photoresist for KrF excimer laser (TDUR-P3116EM 15cp, TOKYO OHKA KOGYA CO., LTD.) and patterned by an exposure tool.…”

Degradation of Polymers for Resist Using Microbubbles on Ozonized Water

“…On the other hand, ozone is applied to environmentally friendly cleaning techniques for water and semiconductor manufacturing [5][6][7][8][9][10][11][12][13][14]. Ozone-water degrade compounds with C=C bond or benzene ring to carboxylic acid [15,16].…”