Assessing the Oxidative Degradation of N-Methylpyrrolidone (NMP) in Microelectronic Fabrication Processes by Using a Multiplatform Analytical Approach

Figure 3

LC/UV chromatogram of NMP. (a) Standard; (b) after catalytic oxidation, NMP was mainly degraded into RRT 0.92 (10.5%), NMS (15%), and RRT 1.16 (11.4%) and other minor degradation products at RRT 0.27 (2.5%), RRT 1.52 (1.2%), and RRT 1.82 (0.8%). (c) Degradation was substantially suppressed under nitrogen atmosphere with RRT 0.92 (∼4.3%), and NMS (∼2.8%) being the main degradation products. NM4ABA: N-methyl-4-aminobutanoic, NMS: N-methylsuccinimide, 5-HNMP: 5-hydroxy-N-methylpyrrolidone, FP: 1-formyl-2-pyrrolidone, 2-AP: 1-(2-Hydroxyethyl)-2-pyrrolidone, 2-NEP: 1-acetyl-2-pyrrolidone, NEP: N-ethylpyrrolidone and NMP: N-methylpyrrolidone. (d–h) Known NMP degradation products and process impurities standard solution mix. NMP, NMS, 2P: 2-pyrrolidone, NHEP: N-hydroxyethyl-2-pyrrolidone, NHMP: N-hydroxy-N-methyl-2-pyrrolidone.