Evolution of Silicon Cleaning Technology Over the Last Twenty Years
J. Ruzyllo
1
, T. Hattori
2
, R.E. Novak
3
, P. Mertens
4
, and P. Besson
5
1
Dept. of Electrical Engineering, Penn State Univ., University Park, PA 16802, USA
2
Hattori Consulting., Chigasaki 253-0061 , Japan,
3
Akrion, Inc. ,Allentown, PA 18106, USA
4
IMEC, Leuven B-3001, Belgium,
5
STM/LETI, Grenoble, France.
This paper briefly summarizes selected developments that were marking
progress in silicon cleaning technology over the last twenty years. The
occasion for this review is a 10th International Symposium on Cleaning
and Surface Conditioning Technology in Semiconductor Device
Manufacturing organized under the auspices of the Electrochemical
Society. This review considers general trends underlying the progress in
cleaning technology, specific developments in the area of removal of
various types of contaminants, as well as cleaning metrology. The
concluding observation from this review is that the wafer cleaning
technology is keeping up with increasing needs through continuous
progress in all its facets. This progress will need to continue if the
challenges resulting from increased complexity of device structures, new
materials used, and the need to address environmental concerns are to be
resolved.
Introduction
The wafer cleaning is a single most frequently applied processing step in advanced
IC manufacturing. Its role in the overall sequence and impact on the manufacturing yield
was growing as device geometries were getting tighter and quality of silicon wafers was
improving, thus, reducing the impact of bulk defects. Eventually, the silicon cleaning
technology has developed into a self-contained important technical domain which, in
order to grow, required a solid scientific foundation.
The First International Symposium on Cleaning and Surface Conditioning
Technology in Semiconductor Device Manufacturing was held in 1989. It was the very
first topical symposium devoted entirely to the problems of surface cleaning and
contamination control in semiconductor manufacturing. It was organized almost exactly
twenty years after the first paper proposing a complete scientifically based cleaning
sequence of silicon surfaces (RCA clean) was published [1]. The extent to which
semiconductor industry transformed itself since then is underscored by the two orders of
magnitude reduced device geometry and close to an order of magnitude increased wafer
area. In terms of cleaning technology these two figures mean a perpetual challenge to
effectively clean continuously decreasing geometries over the continuously increasing
area.
On the occasion of the 10
th
anniversary of the “ECS Cleaning Symposia” this
overview attempts to briefly summarize key trends and developments in silicon cleaning
ECS Transactions, 11 (2) 3-7 (2007)
10.1149/1.2779356 ©The Electrochemical Society
3
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