ASTM F1238-95(2011)

Standard Specification for Refractory Silicide Sputtering Targets for Microelectronic Applications (Withdrawn 2020)

ABSTRACT
This specification covers refractory silicide sputtering targets for use in microelectronic applications. Targets shall be classified by the following major constituents: molybdenum silicide, tantalum silicide, titanium silicide, and tungsten silicide. Target composition shall be stated as the atomic ratio of silicon to metal and shall conform to the prescribed maximum impurity level for: alkalis (potassium, lithium, sodium), refractory metals (molybdenum, tantalum, titanium, and tungsten), iron, other metals (aluminum, boron, calcium, cobalt, chromium, copper, magnesium, manganese, and nickel), carbon, and oxygen. Low alpha grade targets shall contain the prescribed maximum impurity level of uranium and thorium Dimensional and physical properties such as relative, actual, and theoretical densities are specified. The actual target density shall be determined by Archimedes principle or other acceptable techniques and the theoretical density shall be calculated from the given formula. The following chemical analytical methods shall be used: atomic absorption, combustion or infrared spectrometry, inert gas fusion, and alpha-emission rate analysis, depending on the impurity to be analyzed. There shall be no radial cracks, other cracks, or chips on the sputtering surface.
SCOPE
1.1 This specification covers sputtering targets fabricated from metallic silicides (molybdenum silicide, tantalum silicide, titanium silicide, and tungsten silicide). These targets are referred to as refractory silicide targets, and are intended for use in microelectronic applications.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
WITHDRAWN RATIONALE
This specification covers sputtering targets fabricated from metallic silicides (molybdenum silicide, tantalum silicide, titanium silicide, and tungsten silicide). These targets are referred to as refractory silicide targets, and are intended for use in microelectronic applications.
Formerly under the jurisdiction of Committee F01 on Electronics, this specification was withdrawn in January 2020 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.

General Information

• Status: Withdrawn
• Publication Date: 31-May-2011
• Withdrawal Date: 09-Jan-2020
• ICS: 31.100 - Electronic tubes
• Technical Committee: F01 - Electronics
• Drafting Committee: F01.17 - Sputter Metallization

Relations

• Replaces: ASTM F1238-95(2003) - Standard Specification for Refractory Silicide Sputtering Targets for Microelectronic Applications
• Effective Date: 01-Jun-2011

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F1238 −95 (Reapproved 2011)
Standard Specification for
Refractory Silicide Sputtering Targets for Microelectronic
Applications
This standard is issued under the fixed designation F1238; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4.2 Ratio—Target composition shall be stated as the atomic
ratio of silicon to metal, such asTa/Si 2.5. Ratio tolerance shall
1.1 This specification covers sputtering targets fabricated
be 60.1.Therefore,theacceptablerangefora2.5targetwould
frommetallicsilicides(molybdenumsilicide,tantalumsilicide,
be 2.4 to 2.6.
titanium silicide, and tungsten silicide). These targets are
referred to as refractory silicide targets, and are intended for
NOTE1—Siliconcontentmaybecalculatedfromthefollowingformula:
use in microelectronic applications.
Ratio 3A
Silicon, % 5 3100
1.2 The values stated in SI units are to be regarded as
~Ratio 3A!1B
standard. No other units of measurement are included in this
where:
standard.
A = atomic weight of silicon, and
2-4
B = atomic weight of metal, (see Table 1 ).
2. Terminology
2.1 Definitions of Terms Specific to This Standard:
4.3 Impurities—Maximum impurity levels shall conform to
2.1.1 raw material lot—powder mix lot from which a
the requirements prescribed in Table 2.
number of targets is fabricated.
4.4 Low Alpha Grade—When low alpha grade targets are
2.1.2 relative density—actual target density related to theo-
ordered they shall contain a maximum impurity level of
retical density, (see 3.1.3), stated as percent.
uranium and thorium as agreed upon by the supplier and the
2.1.3 theoretical density—calculated density for given com-
purchaser.The method of analysis for these elements shall also
position as described in 5.3.
be agreed upon.
3. Ordering Information NOTE 2—An alternative method for defining low alpha grade targets is
to specify an alpha-emission rate. Specific methodology and emission rate
3.1 Orders for these targets shall include the following:
shall be agreed upon by supplier and purchaser.
3.1.1 Type and ratio (see 4.1 and 4.2),
4.5 When required by purchaser, supplier will provide a 25
3.1.2 Whether low alpha grade is required, (see 4.4),
g sample of material that is representative of the total produc-
3.1.3 Minimum relative density, if other than 90 %, (see
tion process for the particular raw material lot, (see Section 8).
5.1),
3.1.4 Configuration, (see 6.1),
5. Physical Properties
3.1.5 Whether certification is required, (see 10.1).
5.1 Minimum relative density shall be 90 %. Other relative
densities may be specified by the purchaser.
4. Chemical Composition
5.2 ActualtargetdensityshallbedeterminedbyArchimedes
4.1 Type—Targets shall be classified by the following major
principle or other acceptable techniques.
constituents:
4.1.1 Molybdenum silicide, (Mo/Si),
4.1.2 Tantalum silicide, (Ta/Si),
Molybdenum disilicide and WSi (equilibrim tetragonal phase) densities were
4.1.3 Titanium silicide, (Ti/Si), and
computed from crystal lattice parameters tabulated in “Crystal Data-Determinative
4.1.4 Tungsten silicide, (W/Si).
Tables, Third Edition,” Vol 2, U. S. Department of Commerce, National Bureau of
Standards and the Joint Committee on Powder Diffraction Standards, 1973, and
JCPDS Data File Number 11-195. Tantalum disilicide (hexagonal) and α-TiSi
This specification is under the jurisdiction of ASTM Committee F01 on (orthorhombic) data are from Einspruch, N. G. and Larrabee, G. B., VLSI
Electronics and is the direct responsibility of Subcommittee F01.17 on Sputter Electronics Microstructure Science, Vol 6, Table A.1, Academic Press, NY, NY,
Metallization. 1983.
Current edition approved June 1, 2011. Published June 2011. Originally Binary Alloy Phase Diagrams, Vol 2, ASM, Metals Park, OH.
published as F1238 – 89. Last previous edition approved in 2003 as F1238 – 95 Einspruch, N. G., and Larrabee, G. B., VLSI Electronics Microstructure
(2003). DOI: 10.1520/F1238-95R11. Science, Vol 6, Table A.1, Academic Press, NY, NY, 1983.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1238−95 (2011)
A
TABLE 1 Weights and Densities of Constituents
8. Sampling
Atomic or Molecular
Constituents Density (g/cm )
8.1 Analyses for ratio, (see 4.2) and for impurities, (see 4.3
Weigh
...