Demands on dimensional stability of 'high tech' materials relevant for semiconductor industry are growing considerably. Information about long term stability of materials could be extracted from high resolution length measurements performed within a relatively short time, e.g. using high finesse Fabry-Perot-resonators. However, the length changes observed during the short-term measurements can be overlapped by additional length relaxations induced by even small temperature changes before such measurement is started. This effect is reduced when long-term stability is studied from length measurements repeated in a larger period of time. This paper describes absolute length measurements with PTB's Precision Interferometer performed at four gauge block shaped material samples in order to extract reliable information about their long term stability. The long-term stability was found to be dependent not only on the material and its age itself but also on the material's history. The latter effect regards a one hour heating to 220°C applied to one of two identical sample bodies made of glass-ceramics which is still visible in the measurement results of long-term stability even after a period of almost seven years.

Date Published: 12 January 2009
PDF: 9 pages
Proc. SPIE 7133, Fifth International Symposium on Instrumentation Science and Technology, 71333J (12 January 2009); doi: 10.1117/12.809987

Published in SPIE Proceedings Vol. 7133:
Fifth International Symposium on Instrumentation Science and Technology
Jiubin Tan; Xianfang Wen, Editor(s)