ChemInform Abstract: New Method of Purification of HF Chemicals for Very Large Scale Integration (VLSI) Manufacturing.

Abstract

1997separation and purification methods, chromatography separation and purification methods, chromatography V 0200 -216New Method of Purification of HF Chemicals for Very Large Scale Integration (VLSI) Manufacturing.-Metallic impurities (e.g. Cu) in HF chemicals used in VLSI fabrication degrade the device characteristics. They can be removed by a new method using granular polysilicon (poly-Si) as adsorbent. The Cu removal efficiency of this adsorbent can be improved by an Au deposited poly-Si (Au-poly-Si) which, however, causes Au contamination of the HF. A new Au-removed Au-poly-Si adsorbent, prepared by immersion of Au-poly-Si in aqua regia at 60 • C, exhibits a Cu removal efficiency quite similar to that of Au-poly-Si. The new method, which is more promising for HF than for buffered HF, increases the HF lifetime and, therefore, reduces the amount of HF required for VLSI manufacturing. -(YAMAMOTO, K.; SHIMONO, T.; OKADA, T.; KAWAZAWA, Y.; TATSUNO, T.; J.