Method & Instrumentation for Thick-Film SOI Non-Destructive Characterization

Period of Performance: 04/29/1999 - 04/10/2000


Phase 1 SBIR

Recipient Firm

On-line Technologies, Inc.
87 Church St
East Hartford, CT 06108
Principal Investigator

Research Topics


Thick-film Silicon-On-Insulator (SOI) wafers are now being used to manufacture a variety of electronic products. Reliable manufacturing of advanced SOI-based products requires accurate characterization tools. Presently, the semiconductor industry lacks the necessary instrumentation to non-destructively characterize and qualify SOI wafers with silicon layers thicker than several microns. To meet the demand, a joint venture of On-Line Technologies Inc. and ADE Corporation will develop a combined thick-film SOI characterization tool employing FTIR reflectometry and multi-laser light scatterometry. The system will be able to 1) measure thicknesses of the top silicon and the buried oxide (BOX) layers, resistively and macro-defect concentration in the silicon layer, density of the BOX layer, 2) evaluate the integrity of the interface bond between the silicon film and the BOX layer, and 3) detect defects generated by the wafer treatment. Three innovations will be combined in this project to render infrared practical for SOI characterization: 1) A breakthrough optical system from On-Line Technologies, eliminating spectral artifacts arising from the wafer backside reflections, and providing significantly higher accuracy than conventional FTIR. 2) Multi-layer model-based analysis software providing a flexible way to deduce unknown parameters of interest from the reflectance spectra. 3) Multi-spectral (visible and near-IR) laser scatterometry capable of probing both surface and buried interface quality. Phase I will demonstrate the ability of the proposed technique to non-destructively characterize the key properties of thick-film SOI. A system design for Phase II will be proposed.