ASTM F1761-00(2011)
(Test Method)Standard Test Method for Pass Through Flux of Circular Magnetic Sputtering Targets (Withdrawn 2020)
Standard Test Method for Pass Through Flux of Circular Magnetic Sputtering Targets (Withdrawn 2020)
SIGNIFICANCE AND USE
It is standard practice to use magnetron cathode sputter deposition sources in manufacturing thin film magnetic data storage media. But a ferromagnetic sputtering target tends to shunt a sputtering cathode's magnetic field, thus reducing the efficiency of the sputtering process.
Makers of sputtering targets have developed various means of controlling alloy microstructure to minimize the undesirable cathode shunting effect. Because of their differing manufacturing methods, however, the targets of one supplier may have magnetic properties significantly better or worse than those of another, even when the alloy compositions are the same.
This test method permits comparing the magnetic shunting power of magnetic targets under a standard test condition. The results are useful to sputtering target suppliers and buyers in predicting target performance, in specifying target quality, and in qualifying incoming target shipments. This test may also be useful in quantifying target improvement efforts.
Manufacturing process steps that lower a target material's magnetic permeability tend to increase the PTF, and vice versa. It would in principle be possible to predict the PTF by accumulating sufficient permeability data, and knowing the target thickness and the field intensity of the magnetic assembly used for magnetron sputtering.
SCOPE
1.1 This test method covers measuring the dc magnetic field transmitted through a ferromagnetic sputtering target (“pass through flux” or “PTF”). In this test method the source magnetic field is in the test target's circumferential direction.
1.2 Planar disk-shaped targets in the diameter range 5 to 8 in. inclusive (125 to 205 mm inclusive) and of thickness 0.1 to 0.5 in. inclusive (2.5 to 13 mm) may be characterized by this procedure.
1.3 This test method is also applicable to targets having an open center, for example, to targets 5-in. outside diameter by 2.5-in. inside diameter by 0.25-in. thick (127-mm outside diameter by 63.5-mm inside diameter by 6.35-mm thick).
1.4 Targets of various diameters and thicknesses are accommodated by suitable fixturing to align the piece under test with the source magnet mounted in the test fixture. Tooling, covering several popular target designs is specified in this procedure. Additional target configurations may be tested by providing special tooling. When special fixturing is used all parties concerned with the testing must agree to the test setup.
1.5 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.
1.6 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 test method covers measuring the dc magnetic field transmitted through a ferromagnetic sputtering target (“pass through flux” or “PTF”). In this test method the source magnetic field is in the test target's circumferential direction.
Formerly under the jurisdiction of Committee F01 on Electronics, this test method 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
Relations
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: F1761 − 00 (Reapproved 2011)
Standard Test Method for
Pass Through Flux of Circular Magnetic Sputtering Targets
This standard is issued under the fixed designation F1761; 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 2.1.1.1 Discussion—PTF is also frequently called “leakage
flux.”
1.1 This test method covers measuring the dc magnetic field
2.1.2 reference field, n—For purposes of this standard the
transmitted through a ferromagnetic sputtering target (“pass
“reference field” is the dc magnetic field measured with the
through flux” or “PTF”). In this test method the source
Hall probe Gaussmeter when no sputtering target is in position
magnetic field is in the test target’s circumferential direction.
on the test stand. The strength of the reference field depends
1.2 Planar disk-shaped targets in the diameter range 5 to 8
upon the height and position of the Hall probe relative to the
in. inclusive (125 to 205 mm inclusive) and of thickness 0.1 to
source magnet.
0.5 in. inclusive (2.5 to 13 mm) may be characterized by this
2.1.3 source field, n—For purposes of this standard the
procedure.
“source field” is the dc magnetic field measured with the Hall
1.3 This test method is also applicable to targets having an
probe at the top surface of the target support table.
open center, for example, to targets 5-in. outside diameter by
2.5-in. inside diameter by 0.25-in. thick (127-mm outside
3. Summary of Test Method
diameter by 63.5-mm inside diameter by 6.35-mm thick).
3.1 The sputtering target under test is mounted on a test
1.4 Targets of various diameters and thicknesses are accom-
fixture in which a permanent horseshoe-shaped magnet is held
modated by suitable fixturing to align the piece under test with
in proximity to one of the flat planar faces of the target.AHall
the source magnet mounted in the test fixture. Tooling, cover-
probe Gaussmeter is used to measure the dc magnetic field
ingseveralpopulartargetdesignsisspecifiedinthisprocedure.
penetrating the target and entering the air space from target’s
Additional target configurations may be tested by providing
opposite face.
special tooling. When special fixturing is used all parties
concerned with the testing must agree to the test setup.
4. Significance and Use
1.5 The values stated in inch-pound units are to be regarded
4.1 It is standard practice to use magnetron cathode sputter
as standard. The values given in parentheses are mathematical
deposition sources in manufacturing thin film magnetic data
conversions to SI units that are provided for information only
storage media. But a ferromagnetic sputtering target tends to
and are not considered standard.
shunt a sputtering cathode’s magnetic field, thus reducing the
1.6 This standard does not purport to address all of the
efficiency of the sputtering process.
safety concerns, if any, associated with its use. It is the
4.2 Makers of sputtering targets have developed various
responsibility of the user of this standard to establish appro-
means of controlling alloy microstructure to minimize the
priate safety and health practices and determine the applica-
undesirable cathode shunting effect. Because of their differing
bility of regulatory limitations prior to use.
manufacturing methods, however, the targets of one supplier
mayhavemagneticpropertiessignificantlybetterorworsethan
2. Terminology
those of another, even when the alloy compositions are the
2.1 Definitions:
same.
2.1.1 pass through flux (PTF), (n)—For purposes of this
4.3 This test method permits comparing the magnetic shunt-
standard the “pass through flux” is the dc magnetic field
ing power of magnetic targets under a standard test condition.
transmittedthroughaferromagneticsputteringtarget,fromone
The results are useful to sputtering target suppliers and buyers
face to the opposite face.
in predicting target performance, in specifying target quality,
andinqualifyingincomingtargetshipments.Thistestmayalso
This test method is under the jurisdiction of ASTM Committee F01 on
be useful in quantifying target improvement efforts.
Electronics and is the direct responsibility of Subcommittee F01.17 on Sputter
Metallization.
4.4 Manufacturing process steps that lower a target materi-
Current edition approved June 1, 2011. Published June 2011. Originally
al’s magnetic permeability tend to increase the PTF, and vice
approved in 1996. Last previous edition approved in 2005 as F1761 – 00 (05). DOI:
10.1520/F1761-00R11. versa. It would in principle be possible to predict the PTF by
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1761 − 00 (2011)
accumulating sufficient permeability data, and knowing the shims under the magnet, and retightening the clamp screws.
target thickness and the field intensity of the magnetic assem- Recheck magnet location, in accordance with 7.1, if shims are
bly used for magnetron sputtering. adjusted.
7.3 Activate, zero, and calibrate the measuring Gaussmeter
5. Interferences
(6.2) using the manufacturer’s instructions.
5.1 The magnetic test fixture must be located in an area free
7.4 Mount the Gaussmeter probe in the fixture’s Hall probe
of extraneous ferromagnetic materials and strong magnetic
support tube. The bottom tip of the probe should extend 0.050
fields that would interfere with the source magnet—test speci-
6 0.025 in. (1.25 6 0.64 mm) beyond the support tube.
men dc magnetic-field configuration.
Mounted properly, the probe tip will be clearly visible, sticking
5.2 The “magnetic conditioning” effect is strong in some
out of its support. Gently tighten the nylon clamping screws to
sputtering target alloys. It is important to verify that the target
secure and center the Hall probe blade in position in the probe
under test is magnetically stabilized before finalizing a data set
support tube. Excessive tightening may result in damage to the
(see 9.2).
probe that can affect test results.
7.5 By visual sighting, align the Hall probe as indicated in
6. Apparatus
Fig.1,butwiththeprobetipclosetobutnottouchingthetarget
6.1 This method requires the use of a special test fixture. Its
support table. The Hall probe should be roughly centered
construction is specified in Appendix X1.
between the magnet poles, and the flats of the probe blade
6.2 Gaussmeter, is required, equipped with a portable
should be parallel to the fixture’s long dimension. Note that the
transverse-field Hall probe blade nominally 0.040-in. thick by
outer vertical edge of the probe blade is aligned with the side
0.170-in. wide by 2.5-in. long (1.0-mm by 4.3-mm by 64 mm).
of the magnet, illustrated in Fig. 1. Loosen the post attachment
The Gaussmeter must be capable of measuring dc magnetic
screw at the baseplate and adjust the Hall probe post position,
fields in the range 10 Gauss to 3500 Gauss, inclusive, to an
if necessary, to achieve the correct location.
accuracy of 62 %. This unit is designated the “measuring
7.5.1 To make the adjustments indicated in this and subse-
Gaussmeter,” and is used for making the magnetic field
quent paragraphs, it may be necessary to loosen and retighten
measurements specified in this test method.
the collars on the Hall probe support post and the appropriate
6.2.1 It is important that the semiconductor Hall probe
nylon clamping screws, which secure other parts of the
sensing element be mounted at the extreme tip end of the
apparatus.
probe. The distance from the probe tip to the center of the
7.6 Lower the support arm until the Hall probe blade tip is
sensing element must not exceed 0.030 in. (0.75 mm).
in bare (light) contact with the target support table. Note the
6.3 It is convenient to have a second Gaussmeter available,
Gaussmeter reading. Swing (rotate) the cross arm to center the
alsoequippedwithaportabletransverse-fieldHallprobeblade.
probe blade between the magnetic poles, and slightly rotate the
This unit must be capable of measuring dc magnetic fields in
probe support tube, as necessary, to maximize the Gaussmeter
the range 1 Gauss to 50 Gauss, inclusive, to an accuracy of
readings.TheproperpositionisachievedwhentheGaussmeter
620 %. This unit is referred to in 8.1 as the “screening
reading indicates a clear maximum in the magnetic field
Gaussmeter.” It is used to monitor residual magnetic fields in
strength.
test specimen sputtering targets.
NOTE 2—If a clear maximum cannot be identified, the Hall probe blade
NOTE 1—If a “screening Gaussmeter” is not available, the targets under
is not adequately centered in the probe support tube (see 7.4), or the blade
testmustbedegaussedandverified(8.3)usingthemeasuringGaussmeter,
is not in correct transverse alignment (7.6), Repeat 7.4 or 7.6 as required,
before starting Section 7.
to provide a discernible maximum point in 7.6.
6.4 Demagnetizer , is needed that is capable of removing
7.6.1 The maximum Gaussmeter reading at the target sup-
the remnant magnetization in sputtering targets to be tested.
port table (7.6) is the “source field” (2.1.3).
7. Preparation of Apparatus
NOTE 3—Measuring and recording (preferably using an SPC control
chart) the source field provides important information about the stability
7.1 Verify that the source magnet is securely clamped with
of the measuring system. A significant deviation in source field strength
its vertical center plane located 5.750 6 0.015 in. (146.1 6 0.4
may indicate a problem with the Hall probe, or a change in the operating
mm) from the end of the baseplate. This is illustrated in Fig. 1.
environment that may influence the test results.
7.2 Verify that the pole faces of the source magnet are in
7.7 The source field (7.6.1) must be in the range 825 6 50
light contact with the bottom of the target support table.
Gauss.
Adjustment of the magnet’s vertical position can be made by
7.7.1 If the dc magnetic field is not in the required range
loosening the magnet clamp screws, inserting nonmagnetic
(7.7) the Hall probe should be inspected and replaced if any
evidence of damage is observed. If there are no indications of
probe damage the measurement of the source field (7.2 – 7.6)
The sole source of supply of the demagnetizer, 60-Hz hand held coil known to
should be repeated, as needed, until the requirement of 7.7 is
thecommitteeatthistimeisRealisticHighPowerVideo/AudioTapeEraser,catalog
satisfied.
number44-233AfromRadioShack.Ifyouareawareofalternativesuppliers,please
provide this information to ASTM Headquarters. Your comments will receive
7.8 Lift the probe support c
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.