Depth profile metrology using grazing incidence X-ray fluorescence
US6173036A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 31, 1998 |
| Grant date | Jan 9, 2001 |
| Priority date | — |
| Expiry date | Jul 31, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2223/076
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
For small angles that are near critical angle, a primary incident X-ray beam has excellent depth resolution. A series of X-ray fluorescence measurements are performed at varying small angles and analyzed for depth profiling of elements within a substrate. One highly useful application of the X-ray fluorescence measurements is depth profiling of a dopant used in semiconductor manufacturing such as arsenic, phosphorus, and boron. In one example, angles are be varied from 0.01.degree. to 0.20.degree. and measurements made to profile arsenic distribution within a semiconductor wafer. In one embodiment, measurements are acquired using a total reflection X-ray fluorescence (TXRF) type system for both known and unknown profile distribution samples. The fluorescence measurements are denominated in counts/second terms and formed as ratios comparing the known and unknown sample results. The count ratios are compared to ratios of known to unknown samples that are acquired using a control analytical measurement technique. In one example the control technique is secondary ion mass spectroscopy (SIMS) so that the count ratios from the TXRF-type measurements are compared to ratios of integrals of…
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