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Automated Trace Metal Analysis
VPD - ICPMS
The Vapor Phase Decomposition (VPD) Process
Native Oxide
Silicon substrate
1) VPD
2) Scanning droplet 3) Trace metal analysis
Analytical Techniques for Trace Metals
ANALYTICAL TECHNIQUE
VPD-ICPMS SURFACE SIMS TXRF
TOF SIMS
107 108 109 1010 1011 1012 1013
DETECTION LIMIT (at/cm
2)
Vapor Phase Decomposition ICP-MS
¾ VPD ICP-MS is widely used because of its merit of detection limit and its capability to providing a full wafer surface analysis
¾ It is a survey method and provides detection sensitivity at the 107-1010 atoms/cm2range
¾ The scanning droplet may alternatively be analyzed by TXRF, then referred to as VPD TXRF
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• Automated VPD system can measure in selective areas
• Distribution of contamination is not uniform across the wafer
Zone 3 Zone 2 Zone 1
Zone 1
Zone 4 Zone 3
Zone 2
Analytical Services
cascadescientific
global analytical services
For High Technology Industries and Research
Element Spike Recovered % Recovery Conc. (ppt) Conc. (ppt)
Li 213 217 102
Na 213 225 106
Mg 213 211 99
Al 213 211 99
K 213 222 104
Ca 213 185 87
Cr 213 219 103
Mn 213 209 98
Fe 213 224 105
Co 213 211 99
Ni 213 217 102
Cu 213 221 104
Zn 213 213 100
VPD – ICPMS Detection Levels, Recovery rates and a set of Standard Data for 24 elements
Surface Contamination Level ( Units of 10
8atoms / cm
2) for four 200mm
wafers. The Detection levels quoted below are for 200mm Wafers. For 300mm wafers, the detection levels will improve by approx. one order of magnitude.
Samples Li Na Mg Al K Ca Ti Cr Mn Fe Co Ni Cu Zn Ga Ge As Mo In Sn Ba Hf Ta W Detection Limit 6 5 3 5 5 5 50 4 4 3 3 3 3 3 3 5 3 3 3 3 3 3 3 3 Slot 12 - - 33 25 - 10 - - - 6 - - - 3 - - 20 - - 189 - - - -
