Title :
Wafer Thickness Sensor (WTS) for etch depth measurement of TSV
Author :
Marx, David ; Grant, David ; Dudley, Russ ; Rudack, Andy ; Teh, W.H.
Author_Institution :
Tamar Technol., Newbury Park, CA, USA
Abstract :
The wafer thickness sensor (WTS) is an optical, non-destructive sensor that directly measures the etch depth of vias, without regard to aspect ratio. The high throughput measurements of via depth after the etching of through silicon vias (TSV) will allow timely feedback for process control, process development, and the prevention of process excursions in 3D IC process technology. In this paper, we report the capabilities and limitations of the WTS for the measurement of TSV etched depth. Etch depth measurement results are presented for a variety of vias, including 1 mum, 3 mum, and 5 mum diameter vias, vias with an aspect ratio of 28:1, and both isolated and densely packed vias. Results include accuracy and repeatability data, with a route towards providing a high volume manufacturing TSV etch metrology solution for 3D IC process technology.
Keywords :
etching; integrated circuits; optical sensors; optical variables measurement; spatial variables measurement; 3D IC process technology; aspect ratio; etch depth measurement; high throughput measurements; nondestructive sensor; optical distance measurement; optical sensor; process control; size 1 mum; size 3 mum; size 5 mum; through silicon vias; wafer thickness sensor; Etching; Isolation technology; Optical feedback; Optical sensors; Process control; Silicon; Thickness measurement; Three-dimensional integrated circuits; Through-silicon vias; Throughput; Etch depth measurement; Etching; Optical distance measurement; Through silicon via;
Conference_Titel :
3D System Integration, 2009. 3DIC 2009. IEEE International Conference on
Conference_Location :
San Francisco, CA
Print_ISBN :
978-1-4244-4511-0
Electronic_ISBN :
978-1-4244-4512-7
DOI :
10.1109/3DIC.2009.5306536
