WET Organic Impurities induced Carbon Contamination on Surface/Sub-surface of Silicon : CFM: Contamination Free Manufacturing

Carbon contaminations on surface & sub-surface of silicon (Si) are characterized using Auger method. The surface carbon atomic % on Si of post treatment with H
3
PO
4
(for nitride etch), BOE (buffer HF for oxide etch) & SC1 (standard clean for organic removal) is 4.0%, 6.0% & 1.7% respectively, with significantly higher for sample of post BOE. BOE chemicals of fresh, mid-processing & end-processing baths were sampled for gas chromatography-mass spectrometry (GC-MS) analysis where significant amount of cyclopentasiloxane & benzene were detected using hexane extraction. Cyclopentatsiloxane & benzene level was reduced from 1.7 x 10
⁵
to 0.45 x 10
⁵
& 0.7 x 10
⁵
to 0.4 x 10
⁵
count per second (cps) respectively, from fresh to end-processing chemicals. This indicates that the organic impurities in the solution might have been adsorbed or incorporated into the Si layers during oxide etching process. Auger & GC-MS proved to be efficient in monitoring & controlling of organic impurities in semiconductor process.