ASTM F1259M-96

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Designation: F 1259M – 96
METRIC
Standard Guide for
Design of Flat, Straight-Line Test Structures for Detecting
Metallization Open-Circuit or Resistance-Increase Failure
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Due to Electromigration [Metric]
This standard is issued under the fixed designation F 1259M; 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 3.1.3 metallization—the thin-film metallic conductor that
serves as the primary conductor path in electrical interconnects
1.1 This guide covers recommended design features for test
of microelectronic integrated circuits.
structures used in accelerated stress tests, as described in Test
Method F 1260M, to characterize the failure distribution of
4. Significance and Use
interconnect metallizations that fail due to electromigration.
4.1 This guide is intended for the design of test structures
1.2 This guide is restricted to structures with a straight test
used in measuring the median-time-to-failure and sigma (see
line on a flat surface that are used to detect failures due to an
Test Method F 1260M) of metallizations fabricated in ways
open-circuit or a percent-increase in resistance of the test line.
that are of interest to the parties to the test.
1.3 This guide is not intended for testing metal lines whose
4.2 This guide is intended to provide design features that
widths are approximately equal to or less than the estimated
facilitate accurate test-line resistance measurements used in
mean size of the metal grains in the metallization line.
estimating metallization temperature. The design features are
1.4 This guide is not intended for test structures used to
also intended to promote temperature uniformity along the test
detect random defects in a metallization line.
line and a minimum temperature gradient at the ends of the test
1.5 Metallizations tested and characterized are those that are
line when significant joule heating is produced during the
used in microelectronic circuits and devices.
accelerated stress test.
2. Referenced Documents
5. Design Features
2.1 ASTM Standards:
5.1 The test structure shall have at least four terminals: two
F 1260M Test Method for Estimating Electromigration
to conduct current and two to measure the voltage. The basic
Median-Time-To-Failure and Sigma of Integrated Circuit
2 features are illustrated in Fig. 1.
Metallizations [Metric]
5.1.1 The metallization to be characterized by the test
F 1261M Test Method for Determining the Average Elec-
2 structure shall be in the form of a straight test line of width w,
trical Width of a Straight, Thin-Film Metal Line [Metric]
where w shall be larger than the estimated mean size of the
3. Terminology metal grains in the metallization of the test line.
3.1 Definitions of Terms Specific to This Standard:
NOTE 1—The median-time-to-failure, t , (see Test Method F 1260M)
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3.1.1 test chip—an area on a semiconductor wafer contain-
will be a monotonically increasing function of line width w, when w is
larger than the mean size of the metal grains in the test line.
ing one or more test structures having a specified or implied
NOTE 2—If the mean size of the metal grains in the test line is larger
purpose.
than the line width, there is an increasing probability, for decreasing line
3.1.2 test structure—a passive metallization structure, with
width, that failure will occur in the wider end segment of the structure,
terminals to permit electrical access that is fabricated on a
rather in the test line, for decreasing line width. This is because both t
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semiconductor wafer by the normal procedures used to manu-
and sigma increase with decreasing line width in this regime.
facture microelectronic integrated devices.
5.1.2 The length of the test line shall be 800 μm. Adjacent-
running lines may be included in the design to simulate
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actual-circuit layout, or to serve as monitor lines to detect
This guide is under the jurisdiction of ASTM Committee F-1 on Electronics and
is the direct responsibility of Subcommittee F01.11 on Quality and Hardness
electromigration-induced metal extrusions from the test line.
Assurance.
NOTE 3—The specification on the length of the test line is two-fold: to
Current edition approved June 10, 1996. Published August 1996. Originally
published as F 1259 – 89. Last previous edition F 1259 – 89. facilitate comparison of t values (see Test Method F 1260M), because t
50 50
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Annual Book of ASTM Standards, Vol 10.04.
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