ASTM_F_1761_-_00_2011.pdf

Designation:F176100(Reapproved 2011)Standard Test Method forPass Through Flux of Circular Magnetic Sputtering Targets1This standard is issued under the fixed designation F1761;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers measuring the dc magnetic fieldtransmitted through a ferromagnetic sputtering target(“passthrough flux”or“PTF”).In this test method the sourcemagnetic field is in the test targets circumferential direction.1.2 Planar disk-shaped targets in the diameter range 5 to 8in.inclusive(125 to 205 mm inclusive)and of thickness 0.1 to0.5 in.inclusive(2.5 to 13 mm)may be characterized by thisprocedure.1.3 This test method is also applicable to targets having anopen center,for example,to targets 5-in.outside diameter by2.5-in.inside diameter by 0.25-in.thick(127-mm outsidediameter by 63.5-mm inside diameter by 6.35-mm thick).1.4 Targets of various diameters and thicknesses are accom-modated by suitable fixturing to align the piece under test withthe source magnet mounted in the test fixture.Tooling,cover-ing several popular target designs is specified in this procedure.Additional target configurations may be tested by providingspecial tooling.When special fixturing is used all partiesconcerned with the testing must agree to the test setup.1.5 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definitions:2.1.1 pass through flux(PTF),(n)For purposes of thisstandard the“pass through flux”is the dc magnetic fieldtransmitted through a ferromagnetic sputtering target,from oneface to the opposite face.2.1.1.1 DiscussionPTF is also frequently called“leakageflux.”2.1.2 reference field,nFor purposes of this standard the“reference field”is the dc magnetic field measured with theHall probe Gaussmeter when no sputtering target is in positionon the test stand.The strength of the reference field dependsupon the height and position of the Hall probe relative to thesource magnet.2.1.3 source field,nFor purposes of this standard the“source field”is the dc magnetic field measured with the Hallprobe at the top surface of the target support table.3.Summary of Test Method3.1 The sputtering target under test is mounted on a testfixture in which a permanent horseshoe-shaped magnet is heldin proximity to one of the flat planar faces of the target.A Hallprobe Gaussmeter is used to measure the dc magnetic fieldpenetrating the target and entering the air space from targetsopposite face.4.Significance and Use4.1 It is standard practice to use magnetron cathode sputterdeposition sources in manufacturing thin film magnetic datastorage media.But a ferromagnetic sputtering target tends toshunt a sputtering cathodes magnetic field,thus reducing theefficiency of the sputtering process.4.2 Makers of sputtering targets have developed variousmeans of controlling alloy microstructure to minimize theundesirable cathode shunting effect.Because of their differingmanufacturing methods,however,the targets of one suppliermay have magnetic properties significantly better or worse thanthose of another,even when the alloy compositions are thesame.4.3 This test method permits comparing the magnetic shunt-ing power of magnetic targets under a standard test condition.The results are useful to sputtering target suppliers and buyersin predicting target performance,in specifying target quality,and in qualifying incoming target shipments.This test may alsobe useful in quantifying target improvement efforts.4.4 Manufacturing process steps that lower a target materi-als magnetic permeability tend to increase the PTF,and viceversa.It would in principle be possible to predict the PTF by1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.17 on SputterMetallization.Current edition approved June 1,2011.Published June 2011.Originallyapproved in 1996.Last previous edition approved in 2005 as F1761 00(05).DOI:10.1520/F1761-00R11.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 accumulating sufficient permeability data,and knowing thetarget thickness and the field intensity of the magnetic assem-bly used for magnetron sputtering.5.Interferences5.1 The magnetic test fixture must be located in an area f