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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

)

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

atoms / cm

) 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 - - - -