New interferometric measurement technique for small diameter TSV

High aspect ratio through silicon vias (TSV) present a challenge for measurement of bottom critical dimension (BCD) and depth. TSVs smaller than 5 micron diameter with greater than 12:1 depth to BCD aspect ratio have particularly poor signal to noise ratio in the measured signal. This paper proposes...

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Bibliographic Details
Published in25th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC 2014) pp. 37 - 41
Main Authors Timoney, Padraig, Fisher, Daniel, Yeong-Uk Ko, Vaid, Alok, Thangaraju, Sarasvathi, Smith, Daniel, Kamineni, Himani, Dingyou Zhang, Alapati, Ramakanth, Wonwoo Kim, Ke Xiao, Edmundson, Holly, Smith, Nigel, Peterson, Brennan, Amin, Hemant, Peak, Jonathan, Johnson, Tim
Format Conference Proceeding
LanguageEnglish
Published IEEE 01.05.2014
Subjects
BCD
Correlation
critical dimension
depth
high aspect ratio
Interference
Interferometry
Noise
Optical interferometry
small
Surface topography
TCD
Through-silicon vias
TSV
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Summary:High aspect ratio through silicon vias (TSV) present a challenge for measurement of bottom critical dimension (BCD) and depth. TSVs smaller than 5 micron diameter with greater than 12:1 depth to BCD aspect ratio have particularly poor signal to noise ratio in the measured signal. This paper proposes a method for improving the interferometric measurement of these very small and high-aspect ratio TSVs with data showing the feasibility of measuring both BCD and depth of 19:1 aspect ratio TSVs. This work demonstrates the capability to analyze the scanning white-light interferometry (SWLI) signal for such high aspect ratio TSV BCD and depth measurements with >0.95 R 2 correlation to reference metrology obtained through cross section SEM. Precision of within 2.5% of nominal BCD and within 0.1% of nominal depth was demonstrated for 10x repeatability measurements.
ISSN:1078-8743
2376-6697
DOI:10.1109/ASMC.2014.6846973