ASTM F1617-98(2002)

Standard Test Method for Measuring Surface Sodium, Aluminum, Potassium, and Iron on Silicon and EPI Substrates by Secondary Ion Mass Spectrometry (Withdrawn 2003)

SCOPE
This standard was transferred to SEMI (www.semi.org) May 2003
1.1 This test method covers the determination of total sodium, aluminum, potassium, and iron on the surface of mirror-polished single crystal silicon and silicon epi substrates using secondary ion mass spectrometry (SIMS). This test method measures the total amount of each metal, because this test method is independent of the metal's chemistry or electrical activity.
1.2 This test method can be used for silicon with all dopant species and dopant concentrations.
1.3 This test method is especially designed to be used for surface metal contamination that is located within approximately 5 nm of the surface of the wafer.
1.4 This test method is especially useful for determining the surface metal areal densities in the native oxide or chemically grown oxide of polished silicon substrates after cleaning.
1.5 This test method is useful for sodium, aluminum, potassium, and iron areal densities between 109 and 1014 atoms/cm 2. The limit of detection is determined by either the BLANK value or by count rate limitations, and may vary with instrumentation.
1.6 This test method is complementary to:
1.6.1 Total reflection X-ray fluorescence (TXRF), that can detect higher atomic number Z, surface metals such as iron, but does not have useful (1011 atoms/cm2) detection limits for sodium, potassium, and aluminum on silicon.
1.6.2 Electron spectroscopy for chemical analysis and Auger electron spectroscopy that can detect metal surface areal densities down to the order of 1012 to 1013 atoms/cm2 .
1.6.3 Vapor phase decomposition (VPD) of surface metals followed by atomic absorption spectroscopy (AAS) or inductively coupled plasma mass spectrometry (ICP-MS) of the VPD residue, where the metal detection limits are 108 to 1010 atoms/cm2. There is no spatial information available and the VPD preconcentration of metals is dependent upon the chemistry of each metal.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Withdrawn
• Publication Date: 09-May-1998
• Withdrawal Date: 09-May-2003
• ICS: 77.040.30 - Chemical analysis of metals
• Technical Committee: F01 - Electronics

Relations

• Replaces: ASTM F1617-98 - Standard Test Method for Measuring Surface Sodium, Aluminum, Potassium, and Iron on Silicon and EPI Substrates by Secondary Ion Mass Spectrometry
• Effective Date: 10-May-1998

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1617 – 98 (Reapproved 2002)
Standard Test Method for
Measuring Surface Sodium, Aluminum, Potassium, and Iron
on Silicon and EPI Substrates by Secondary Ion Mass
1
Spectrometry
This standard is issued under the fixed designation F 1617; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the determination of total
responsibility of the user of this standard to establish appro-
sodium, aluminum, potassium, and iron on the surface of
priate safety and health practices and determine the applica-
mirror-polished single crystal silicon and silicon epi substrates
bility of regulatory limitations prior to use.
using secondary ion mass spectrometry (SIMS). This test
method measures the total amount of each metal, because this
2. Referenced Documents
test method is independent of the metal’s chemistry or electri-
2.1 ASTM Standards:
cal activity.
E 122 Practice for Choice of Sample Size to Estimate a
1.2 This test method can be used for silicon with all dopant
2
Measure of Quality for a Lot or Process
species and dopant concentrations.
3
E 673 Terminology Relating to Surface Analysis
1.3 This test method is especially designed to be used for
surface metal contamination that is located within approxi-
3. Terminology
mately 5 nm of the surface of the wafer.
3.1 All terms in this test method are in conformance with
1.4 This test method is especially useful for determining the
those given in Terminology E 673.
surface metal areal densities in the native oxide or chemically
grown oxide of polished silicon substrates after cleaning.
4. Summary of Test Method
1.5 This test method is useful for sodium, aluminum,
9 4.1 Specimens of mirror-polished single crystal silicon are
potassium, and iron areal densities between 10 and
14 2 loaded into a sample holder. The holder is transferred into the
10 atoms/cm . The limit of detection is determined by either
analysis chamber of the SIMS instrument.
the BLANK value or by count rate limitations, and may vary
+
4.2 A primary ion beam, typically O , is used to bombard
2
with instrumentation.
each specimen with a sputter rate less than 0.015 nm/s (0.9
1.6 This test method is complementary to:
nm/min).
1.6.1 Total reflection X-ray fluorescence (TXRF), that can
4.3 The area of analysis may be different for different
detect higher atomic number Z, surface metals such as iron, but
11 2 instruments and may range from 100 μm 3 100 μm to 1
does not have useful (<10 atoms/cm ) detection limits for
mm 3 1 mm.
sodium, potassium, and aluminum on silicon.
4.4 Depending upon instrumentation, a molecular oxygen
1.6.2 Electron spectroscopy for chemical analysis and Au-
jet or leak may be focused on the analysis area.
ger electron spectroscopy that can detect metal surface areal
23 27 39 54
4.5 The positive secondary ions Na, Al, K, and Fe
12 13 2
densities down to the order of 10 to 10 atoms/cm .
are mass analyzed by a mass spectrometer, and detected by an
1.6.3 Vapor phase decomposition (VPD) of surface metals
electron multiplier (EM) or equivalent high-sensitivity ion
followed by atomic absorption spectroscopy (AAS) or induc-
detector as a function of time until the signals reach back-
tively coupled plasma mass spectrometry (ICP-MS) of the
ground levels or 1 % of the initial signal rates of each element.
8 10
VPD residue, where the metal detection limits are 10 to 10
2 The instrumentation must be able to discriminate the elemental
atoms/cm . There is no spatial information available and the
ion signals from molecular interferences.
VPD preconcentration of metals is dependent upon the chem-
4.6 A BLANK silicon sample is used to evaluate whether
istry of each metal.
the lower limit of detection arises from molecular ion interfer-
ences, elemental instrumental backgrounds, or count rate
1
This test method is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.06 on Silicon
Materials and Process Control.
2
Current edition approved May 10, 1998. Published July 1998. Originally Annual Book of ASTM Standards, Vol 14.02.
3
published as F 1617 - 95. Last previous edition F 1617 - 95. Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 ----------------------
NOTICE: This standard has either been superceded and replaced by a new versi
...