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.
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.
magnetic data storage media; magnetic field; magnetic sputtering targets; pass through flux; sputtering; sputtering target; D-c magnetic properties; Ferromagnetic sputtering target; Magnetic data storage media; Magnetic/metallic sputtering targets; Pass through flux (PTF); Sputtering process/targets;
ICS Number Code 77.040.20 (Non-destructive testing of metals)
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Citing ASTM Standards
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