As semiconductor industry continues to make patterns smaller and more sophisticated, stable patterns with high AR (aspect ratio) is required. Pattern collapse is often affected by the AR, rigidity of pattern material, and surface chemistry of the sidewalls. Historically, hot IPA treatment was used but it does not support latest generation devices. One of the novel effective pattern collapse prevention approaches is the surface treatment with an organic layer [1, 2]. The modified structure surface has lower surface tension and the capillary force is reduced. This treatment process is normally performed by a silane-coupling reaction using organic solvent, so that the hydrophilic surface (-Si-OH) is modified to hydrophobic (-Si-O-SiR₃) after silylation reaction. Silyning agent has limited stability and decompose upon exposure to air, moisture or reactive surfaces. Thus, there is a need the tight process control. A variety of spectroscopic methods were studied in order to measure selectively the active silyning agent and breakdown byproducts. Presentation will summarize advantages and disadvantages of different approached, preferred process control strategy and test results for non-reagent, real time analyzer of STM chemistry. TOKYO OHKA KOGYO CO., LTD. (TOK) is highly acknowledged for providing test samples and technical discussions.

[1] D. Mori et al. Surface treatment agent and surface treatment method United States Patent Application 15/268,904

[2] E. Kesters et al. Wet clean challenges in 22nm ½ pitch and 16nm ½ pitch Proceedings of SPCC conference 2017