ASTM F1512-94(2011)
(Practice)Standard Practice for Ultrasonic C-Scan Bond Evaluation of Sputtering Target-Backing Plate Assemblies (Withdrawn 2020)
Standard Practice for Ultrasonic C-Scan Bond Evaluation of Sputtering Target-Backing Plate Assemblies (Withdrawn 2020)
SIGNIFICANCE AND USE
This practice supplements Practice E1001 by indicating specific equipment choices and test arrangements appropriate for evaluating sputtering target bonds.
The bond between sputtering target and its supporting backing plate is a critical reliability element in a sputter deposition system. A bond must have high thermal conductivity to provide adequate target cooling during sputtering. The target-backing plate joint must also have strength enough to withstand the shear stresses caused by differential thermal expansion between target and backing plate.
Flaws in a bond, for example, voids in the joining material, degrade bond performance. An inadequate bond may fail in service, potentially causing catastrophic separation of the target from the backing plate. Assurance of sound bonds is an important concern among users of sputtering equipment.
Ultrasonic testing is accepted as an efficient method for evaluating target bonds, but differences in technique inhibit intercomparison of results from one laboratory to another. This practice is intended to promote uniformity in use so that specifications for bond integrity may be universally applied.
The C-span display of ultrasonic test data is a direct method for visually demonstrating bond character. Practice E1001 upon which this practice is modeled, however, does not address C-scan display. Instructions specific to the C-scan display mode are indicated in this practice. In other respects this practice is a section by section commentary on Practice E1001.
SCOPE
1.1 This practice describes a method for ultrasonic mapping of the soundness of a bond joining a sputtering target to its supporting backing plate. The results of the examination may be used in predicting the target-backing plate assembly's suitability for use. Accept/reject standards are not specified; these are subject to agreement between target supplier and user, depending upon the application requirements.
1.2 This standard is intended to be used with Practice E1001.
1.3 The method reveals unbonded areas 0.125 in. (3 mm) in diameter and larger. The technique permits, for example, unambiguous quantitative measurement of the voided area in solder bonds.
1.3.1 This technique may also show regions in which bond integrity is marginally degraded by imperfect adhesion, for example, areas in which oxide inclusion has inhibited the development of full bond strength. Evaluation of indications of degraded bond areas may vary in rigor from purely subjective to semiquantitative. Target supplier and user must agree upon the means used to display and grade partially bonded areas.
1.4 This practice is applicable to assemblies having planar bonds in which the design provides at least one flat plane parallel to the bond that may be used as the entry/exit surface for ultrasonic excitation.
1.5 Only the immersion pulse-echo method is covered.
1.6 Evaluation by this method is intended to be nondestructive. For target assemblies that would be degraded by immersion in demineralized water, for example, for porous target materials, the test should be considered a destructive one.
1.7 This practice is applicable to bonding methods that use a filler material to join the target and backing plate. These include solder, epoxy, and braze bonds.
1.8 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.9 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.
WITHDRAWN RATIONALE
This practice describes a method for ultrasonic mapping of the soundness of a bond joining a sputtering target to its supporting back...
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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: F1512 − 94 (Reapproved 2011)
Standard Practice for
Ultrasonic C-Scan Bond Evaluation of Sputtering
Target-Backing Plate Assemblies
This standard is issued under the fixed designation F1512; 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 conversions to SI units that are provided for information only
and are not considered standard.
1.1 This practice describes a method for ultrasonic mapping
1.9 This standard does not purport to address all of the
of the soundness of a bond joining a sputtering target to its
safety concerns, if any, associated with its use. It is the
supporting backing plate. The results of the examination may
responsibility of the user of this standard to establish appro-
be used in predicting the target-backing plate assembly’s
priate safety and health practices and determine the applica-
suitability for use. Accept/reject standards are not specified;
bility of regulatory limitations prior to use.
thesearesubjecttoagreementbetweentargetsupplieranduser,
depending upon the application requirements.
2. Referenced Documents
1.2 This standard is intended to be used with Practice
2.1 ASTM Standards:
E1001.
E127 Practice for Fabricating and Checking Aluminum Al-
1.3 The method reveals unbonded areas 0.125 in. (3 mm) in
loy Ultrasonic Standard Reference Blocks
diameter and larger. The technique permits, for example,
E428 Practice for Fabrication and Control of Metal, Other
unambiguous quantitative measurement of the voided area in
than Aluminum, Reference Blocks Used in Ultrasonic
solder bonds.
Testing
1.3.1 This technique may also show regions in which bond
E1001 Practice for Detection and Evaluation of Discontinui-
integrity is marginally degraded by imperfect adhesion, for
ties by the Immersed Pulse-Echo Ultrasonic Method
example, areas in which oxide inclusion has inhibited the
Using Longitudinal Waves
development of full bond strength. Evaluation of indications of
E1316 Terminology for Nondestructive Examinations
degraded bond areas may vary in rigor from purely subjective
2.2 American Society for Nondestructive Testing Standard:
to semiquantitative. Target supplier and user must agree upon
ASNT Recommended Practice SNT-TC-1A for Personnel
the means used to display and grade partially bonded areas.
Qualification and Certification in Nondestructive Testing
1.4 This practice is applicable to assemblies having planar
bonds in which the design provides at least one flat plane
3. Terminology
parallel to the bond that may be used as the entry/exit surface
3.1 Definitions:
for ultrasonic excitation.
3.1.1 For definitions of terms used in this practice see
1.5 Only the immersion pulse-echo method is covered.
Practice E1001 and Terminology E1316.
1.6 Evaluation by this method is intended to be nondestruc-
4. Summary of Practice
tive. For target assemblies that would be degraded by immer-
sion in demineralized water, for example, for porous target
4.1 This practice describes a preferred means of applying
materials, the test should be considered a destructive one. PracticeE1001toobtainatwodimensionalmapoftheflawsin
asputteringtarget-backingplatebond.Thetarget-backingplate
1.7 This practice is applicable to bonding methods that use
assembly is immersed in demineralized water, used as a
a filler material to join the target and backing plate. These
couplant, and the target-backing plate joint is scanned ultra-
include solder, epoxy, and braze bonds.
sonically.
1.8 The values stated in inch-pound units are to be regarded
as standard. The values given in parentheses are mathematical
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
This practice is under the jurisdiction ofASTM Committee F01 on Electronics contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
and is the direct responsibility of Subcommittee F01.17 on Sputter Metallization. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved June 1, 2011. Published June 2011. Originally the ASTM website.
approved in 1994. Last previous edition approved in 2003 as F1512–94 (2003). AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
DOI: 10.1520/F1512-94R11. 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1512 − 94 (2011)
5. Significance and Use data acquisition system may be used in which the gated
reflectedsignalissampledataratesufficienttocharacterizethe
5.1 This practice supplements Practice E1001 by indicating
area-modulated ultrasonic reflectance of the bond interface.
specific equipment choices and test arrangements appropriate
These data may be plotted off-line to provide an equivalent
for evaluating sputtering target bonds.
C-scan map.
5.2 The bond between sputtering target and its supporting
6.1.1.2 It is intended that the C-scan plotter be set to make
backing plate is a critical reliability element in a sputter
a full-sized map of the bonded area. If a scaling factor other
deposition system. A bond must have high thermal conductiv-
than 1:1 is used the enlargement/reduction factor may be
ity to provide adequate target cooling during sputtering. The
determined from the reference block scan (see 8.2.3.1, 8.3.3,
target-backing plate joint must also have strength enough to
and 9.1.1).
withstand the shear stresses caused by differential thermal
6.1.2 Plotter—Theplottersystemmustbecapableofresolv-
expansion between target and backing plate.
ing the reference block calibration indications (6.7) with
5.3 Flaws in a bond, for example, voids in the joining contrast sufficient to permit unambiguous identification by the
material, degrade bond performance.An inadequate bond may
unaided eye under ordinary room lighting conditions.
fail in service, potentially causing catastrophic separation of
6.1.3 Data Acquisition System—The data system must be
the target from the backing plate.Assurance of sound bonds is
capable of displaying a C-scan mode plot of the reference
an important concern among users of sputtering equipment.
block calibration indications (6.7) with contrast and resolution
sufficient to permit unambiguous identification by unaided eye
5.4 Ultrasonic testing is accepted as an efficient method for
under ordinary room lighting conditions.Asampling rate of at
evaluating target bonds, but differences in technique inhibit
least 50/in. (2/ mm) of search unit travel is recommended.
intercomparison of results from one laboratory to another.This
Display of the ultrasonic map’s features in contrasting colors
practice is intended to promote uniformity in use so that
may be used to enhance visibility.
specifications for bond integrity may be universally applied.
6.2 Voltage Regulator—Provide if necessary, in accordance
5.5 The C-span display of ultrasonic test data is a direct
with Practice E1001 (6.2).
method for visually demonstrating bond character. Practice
E1001 upon which this practice is modeled, however, does not
6.3 Search Units—Use round, immersion type, single
address C-scan display. Instructions specific to the C-scan
element, straight-beam (longitudinal), focused search units.
display mode are indicated in this practice. In other respects
The focal length must be sufficiently long that the beam
this practice is a section by section commentary on Practice
minimum area may be focused at the target-backing plate
E1001.
interface. Search units 0.375 to 0.500 in. (9.5 to 12.5 mm) in
diameter, tuned at 5 or 10 Mhz operating frequency, with focal
6. Apparatus
length (in water) of 2 to 4 in. (50 to 100 mm) have proved
6.1 Electronic Equipment—Provide electronic equipment in
satisfactory for most applications.
general conformance with the requirements of Practice E1001,
6.4 Alarm—Not applicable for this determination.
6.1. It is recommended that 5 or 10 Mhz frequency be used for
6.4.1 Gate Synchronization—Set the electronic gate syn-
testing sputtering target bonds. The equipment and its cathode-
chronization to lock onto the top surface echo pulse from the
ray tube (CRT) display, operating in the A-scan mode, should
test article (not the primary excitation pulse) as reference. Set
be capable of producing echo amplitudes of at least 60 % of
the gate delay and width to capture the echo pulse from the
full scale, with the noise level no greater than 20 % of full
target/backing plate interface.
scale, using an 0.125-in. (3-mm) diameter flat-bottom test hole
in a reference block (6.7) simulating the assembly under test. 6.5 Manipulating Equipment, should conform to Practice
Note that for C-scan mapping of target bonds theA-scan mode E1001 (6.5).
is used for assisting in the setup only. A-scan data are not
6.6 Tank—Provide tank in accordance with Practice E1001
collected or reported.
(6.6).
6.1.1 C-scan Plotter/Data Acquisition System—The C-scan
6.7 Reference Blocks—Ultrasonic reference blocks, often
presentation is a mapping of the reflected ultrasound pulse
called test blocks, are used to standardize the ultrasonic
intensity (peak voltage) from the target/backing plate interface
equipment and to evaluate indications received from disconti-
as a function of position. Modulations of the reflected inten-
nuities in the test part.
sity“ indications” are indicative of variations in the metallur-
6.7.1 It is mandatory that test blocks specifically made for
gical bond between target and backing plate. The electronic
system may be equipped with a plotter to make C-scan maps sputtering target testing be provided for this procedure. Blocks
should be designed, manufactured, and tested in conformance
on-line as the search unit traces a raster pattern over the test
with Practices E127 and E428.
article’s surface.
6.1.1.1 Suitable plotters may use an electric discharge pen 6.7.2 Test blocks must be 1.5 in. (38 mm) square or
andconductivepaper;amechanicalorelectricallinkagecauses diameter, or larger. In order to duplicate the target-backing
the pen to traverse the paper in synchronism with the search plateassembly,testblocksmustbemadeofthesamematerials,
unit’s raster of the test article. The density of the pen trace is that is, having the same acoustic properties as the article under
made proportional to the reflected ultrasonic pulse from the thetest,ofthesamethicknesses,andjoinedinthesamemanner
target/backing plate interface. Alternatively, a computer-based as the target assembly to be evaluated.
F1512 − 94 (2011)
6.7.2.1 Itiscriticalfortestblockcredibilityt
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