Volume 2, No. 1, June 2002, Pages 53-60 PDF(903 KB)
Dimensional and Elemental Analysis of Particulate Contaminations on Silicon Wafers
Hsunling Bai, Yuhao Kang, Chengchang Li
Institute of Environmental Engineering, National Chiao-Tung University, #75 Po Ai St., Hsinchu 300, Taiwan, ROC
As the dimensions of semiconducting devices continue to shrink, microelectronic devices are becoming increasingly sensitive to micro-contamination on wafer surfaces. This investigation analyzes the particulate morphology, elemental composition and the particle sizes of wafer contaminants in the lithographic process area of a semiconductor plant. Scanning electron microscopic and energy dispersive X-ray spectroscopic analyses identified the elemental compositions of micro-contaminants of silicon wafers as silicon, carbon, oxygen, sodium, magnesium, aluminum, phosphorus, sulfur, chlorine, potassium, calcium, and iron. The organic contaminants on the surfaces of the wafers were approximately 1-2 μm and were the smallest of all the contaminants. Condensation by organic vapors was the likely source of organic contamination. Inorganic particles could also have contaminated the wafer surfaces by sticking onto them. The co-existence of organic and inorganic elements enlarges the wafer contaminants up to 30-50μm. The particle sizes were not directly proportional to the period of exposure of the wafer.
Silicon wafers, Micro-contamination; Airborne molecular contamination (AMC); Clean room; Lithographic process.