1、Designation: F1512 94 (Reapproved 2011)Standard Practice forUltrasonic C-Scan Bond Evaluation of SputteringTarget-Backing Plate Assemblies1This standard is issued under the fixed designation F1512; the number immediately following the designation indicates the year oforiginal adoption or, in the cas
2、e 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 practice describes a method for ultrasonic mappingof the soundness of a bond joining a
3、 sputtering target to itssupporting backing plate. The results of the examination maybe used in predicting the target-backing plate assemblyssuitability for use. Accept/reject standards are not specified;these are subject to agreement between target supplier and user,depending upon the application r
4、equirements.1.2 This standard is intended to be used with PracticeE1001.1.3 The method reveals unbonded areas 0.125 in. (3 mm) indiameter and larger. The technique permits, for example,unambiguous quantitative measurement of the voided area insolder bonds.1.3.1 This technique may also show regions i
5、n which bondintegrity is marginally degraded by imperfect adhesion, forexample, areas in which oxide inclusion has inhibited thedevelopment of full bond strength. Evaluation of indications ofdegraded bond areas may vary in rigor from purely subjectiveto semiquantitative. Target supplier and user mus
6、t agree uponthe means used to display and grade partially bonded areas.1.4 This practice is applicable to assemblies having planarbonds in which the design provides at least one flat planeparallel to the bond that may be used as the entry/exit surfacefor ultrasonic excitation.1.5 Only the immersion
7、pulse-echo method is covered.1.6 Evaluation by this method is intended to be nondestruc-tive. For target assemblies that would be degraded by immer-sion in demineralized water, for example, for porous targetmaterials, the test should be considered a destructive one.1.7 This practice is applicable to
8、 bonding methods that usea filler material to join the target and backing plate. Theseinclude solder, epoxy, and braze bonds.1.8 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 informat
9、ion onlyand are not considered standard.1.9 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
10、limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E127 Practice for Fabricating and Checking AluminumAlloy Ultrasonic Standard Reference BlocksE428 Practice for Fabrication and Control of Metal, Otherthan Aluminum, Reference Blocks Used in UltrasonicTestingE1001 Practice for Detect
11、ion and Evaluation of Disconti-nuities by the Immersed Pulse-Echo Ultrasonic MethodUsing Longitudinal WavesE1316 Terminology for Nondestructive Examinations2.2 American Society for Nondestructive Testing Standard:ASNT Recommended Practice SNT-TC-1A for PersonnelQualification and Certification in Non
12、destructive Testing33. Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice seePractice E1001 and Terminology E1316.4. Summary of Practice4.1 This practice describes a preferred means of applyingPractice E1001 to obtain a two dimensional map of the flaws ina sputtering tar
13、get-backing plate bond. The target-backing plateassembly is immersed in demineralized water, used as acouplant, and the target-backing plate joint is scanned ultra-sonically.1This practice is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee
14、F01.17 on Sputter Metallization.Current edition approved June 1, 2011. Published June 2011. Originallyapproved in 1994. Last previous edition approved in 2003 as F151294 (2003).DOI: 10.1520/F1512-94R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Serv
15、ice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available fromAmerican Society for Nondestructive Testing (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http:/www.asnt.org.1Copyright AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 This practice supplements Practice E1001 by indicatingspecific equipment choices and test arrangements appropriatefor evaluating sputtering target bonds.5.2 The bond betwe
17、en sputtering target and its supportingbacking plate is a critical reliability element in a sputterdeposition system. A bond must have high thermal conductiv-ity to provide adequate target cooling during sputtering. Thetarget-backing plate joint must also have strength enough towithstand the shear s
18、tresses caused by differential thermalexpansion between target and backing plate.5.3 Flaws in a bond, for example, voids in the joiningmaterial, degrade bond performance. An inadequate bond mayfail in service, potentially causing catastrophic separation ofthe target from the backing plate. Assurance
19、 of sound bonds isan important concern among users of sputtering equipment.5.4 Ultrasonic testing is accepted as an efficient method forevaluating target bonds, but differences in technique inhibitintercomparison of results from one laboratory to another. Thispractice is intended to promote uniformi
20、ty in use so thatspecifications for bond integrity may be universally applied.5.5 The C-span display of ultrasonic test data is a directmethod for visually demonstrating bond character. PracticeE1001 upon which this practice is modeled, however, does notaddress C-scan display. Instructions specific
21、to the C-scandisplay mode are indicated in this practice. In other respectsthis practice is a section by section commentary on PracticeE1001.6. Apparatus6.1 Electronic EquipmentProvide electronic equipment ingeneral conformance with the requirements of Practice E1001,6.1. It is recommended that 5 or
22、 10 Mhz frequency be used fortesting sputtering target bonds. The equipment and its cathode-ray tube (CRT) display, operating in the A-scan mode, shouldbe capable of producing echo amplitudes of at least 60 % offull scale, with the noise level no greater than 20 % of fullscale, using an 0.125-in. (3
23、-mm) diameter flat-bottom test holein a reference block (6.7) simulating the assembly under test.Note that for C-scan mapping of target bonds the A-scan modeis used for assisting in the setup only. A-scan data are notcollected or reported.6.1.1 C-scan Plotter/Data Acquisition SystemThe C-scanpresent
24、ation is a mapping of the reflected ultrasound pulseintensity (peak voltage) from the target/backing plate interfaceas a function of position. Modulations of the reflected inten-sity“ indications” are indicative of variations in the metallur-gical bond between target and backing plate. The electroni
25、csystem may be equipped with a plotter to make C-scan mapson-line as the search unit traces a raster pattern over the testarticles surface.6.1.1.1 Suitable plotters may use an electric discharge penand conductive paper; a mechanical or electrical linkage causesthe pen to traverse the paper in synchr
26、onism with the searchunits raster of the test article. The density of the pen trace ismade proportional to the reflected ultrasonic pulse from thetarget/backing plate interface. Alternatively, a computer-baseddata acquisition system may be used in which the gatedreflected signal is sampled at a rate
27、 sufficient to characterize thearea-modulated ultrasonic reflectance of the bond interface.These data may be plotted off-line to provide an equivalentC-scan map.6.1.1.2 It is intended that the C-scan plotter be set to makea full-sized map of the bonded area. If a scaling factor otherthan 1:1 is used
28、 the enlargement/reduction factor may bedetermined from the reference block scan (see 8.2.3.1, 8.3.3,and 9.1.1).6.1.2 PlotterThe plotter system must be capable of re-solving the reference block calibration indications (6.7) withcontrast sufficient to permit unambiguous identification by theunaided e
29、ye under ordinary room lighting conditions.6.1.3 Data Acquisition SystemThe data system must becapable of displaying a C-scan mode plot of the referenceblock calibration indications (6.7) with contrast and resolutionsufficient to permit unambiguous identification by unaided eyeunder ordinary room li
30、ghting conditions. A sampling rate of atleast 50/in. (2/ mm) of search unit travel is recommended.Display of the ultrasonic maps features in contrasting colorsmay be used to enhance visibility.6.2 Voltage RegulatorProvide if necessary, in accordancewith Practice E1001 (6.2).6.3 Search UnitsUse round
31、, immersion type, single ele-ment, straight-beam (longitudinal), focused search units. Thefocal length must be sufficiently long that the beam minimumarea may be focused at the target-backing plate interface.Search units 0.375 to 0.500 in. (9.5 to 12.5 mm) in diameter,tuned at 5 or 10 Mhz operating
32、frequency, with focal length (inwater) of 2 to 4 in. (50 to 100 mm) have proved satisfactory formost applications.6.4 AlarmNot applicable for this determination.6.4.1 Gate SynchronizationSet the electronic gate syn-chronization to lock onto the top surface echo pulse from thetest article (not the pr
33、imary excitation pulse) as reference. Setthe gate delay and width to capture the echo pulse from thetarget/backing plate interface.6.5 Manipulating Equipment, should conform to PracticeE1001 (6.5).6.6 TankProvide tank in accordance with Practice E1001(6.6).6.7 Reference BlocksUltrasonic reference bl
34、ocks, oftencalled test blocks, are used to standardize the ultrasonicequipment and to evaluate indications received from disconti-nuities in the test part.6.7.1 It is mandatory that test blocks specifically made forsputtering target testing be provided for this procedure. Blocksshould be designed, m
35、anufactured, and tested in conformancewith Practices E127 and E428.6.7.2 Test blocks must be 1.5 in. (38 mm) square ordiameter, or larger. In order to duplicate the target-backingplate assembly, test blocks must be made of the same materials,that is, having the same acoustic properties as the articl
36、e underthe test, of the same thicknesses, and joined in the same manneras the target assembly to be evaluated.6.7.2.1 It is critical for test block credibility that the bondingof target and backing plate materials be sound in areas notpurposefully altered to provide calibration indications (6.7.4,F1
37、512 94 (2011)26.7.5). New test blocks should be surveyed using the method ofSection 8 after laminating. Imperfect bonds should be re-worked or the test blocks discarded.6.7.3 The top surface finish of the test blocks must be thesame as the article under test.6.7.4 Three precision flat bottomed holes
38、, arranged in apattern as illustrated in Fig. 1 must be drilled from the backside of the test block. The diameters of the holes are 0.125,0.250 and 0.500 in. (3, 6, and 13 mm). The holes shall be deepenough to penetrate the bond interface, 60.005 in. (60.13mm). After drilling, the holes must be clea
39、ned, tested, andsealed as described in Practices E127 and E428.6.7.5 Additional purposeful discontinuities may be providedto simulate areas in which the metallurgical bond is degradedby oxide inclusions or residual contamination on the bondedsurfaces. Whether such artifacts will be provided, and the
40、irnature, should be agreed upon in advance by the parties to theevaluation. The validity of purposefully degraded areas inreference blocks for simulating actual bond flaws must beverified, for example, by tensile tests, metallographic exami-nation of bond interface sections, or by other means.7. Gen
41、eral Examination Requirements7.1 Material ConditionPerform the ultrasonic bond teston finished target-backing plate assemblies. Baking the assem-bly to dry it after immersion, and final cleanup and packaging,are usual steps required to prepare the test article for deliveryto a user.7.2 CoverageThe b
42、onded area should be scanned.7.3 Ultrasonic FrequencyUse 10 Mhz for most applica-tions.8. Procedure8.1 Examination (Scanning) System Setup:8.1.1 TankImmerse the part to be inspected, referenceblocks, and search unit in tank filled with demineralized water.Make sure that the couplant water is clean a
43、nd deaerated toeliminate attenuation of the sound beam, to improve the signalto noise ratio, and to minimize contamination of the sputteringtarget. Do not add corrosion inhibitors or wetting agents.Remove air bubbles that collect on the test article, referenceblocks, and search unit.8.1.1.1 Generall
44、y the test article will be mounted in the tanktarget side up. In this orientation the target face is the entryplane for ultrasonic pulses. In special cases better results maybe obtained by mounting target side down. The reference blockconstruction must duplicate the target assembly orientation.8.1.2
45、 Reference Block SelectionUse reference blocks du-plicating the target-backing plate construction. All inspectionsare conducted in the far field portion of the sound beam.8.1.3 Search Unit AdjustmentFollow the instructions ofPractice E1001 (8.1.3) to adjust the search unit so thatmaximum echo amplit
46、ude is received from the sound-entrysurface. Adjust the distance from the search unit to test articlesurface so that the target-backing plate interface is at the beamfocus. This is accomplished by maximizing the pulse echosignal from the bond interface.8.1.4 Water PathFollow the instructions of Prac
47、ticeE1001 (8.1.4). For most applications it is sufficient that thewater path be uniform across the surface of the test article to60.05 in. (61.3 mm).8.2 Initial Scanning Standardization:8.2.1 Scan IndexUse a scan index of 0.020 in. (0.5 mm).8.2.2 Distance-Amplitude RelationshipNot applicable tothis
48、determination.8.2.3 Scanning Gain DeterminationPlace the referenceblock next to the test article, and at the same height. Set theCRT display in the A-scan mode and adjust gain and gatesettings to capture the echo signal from reference blocksreflector holes.8.2.3.1 C-Scan Plotter SystemScan the refer
49、ence block,readjusting the gain settings as necessary to provide a clearlyresolved image of the three reflector holes (6.7). Ideally, theholes will be saturated black against a slightly grey back-ground. Make further refinements of the gain and gate settingsas necessary to provide adequate visual contrast for additionalindications, if incorporated into the reference blocks (6.7.5).8.2.3.2 Digital Data Acquisition SystemActivate the dataacquisition system. Scan the reference block to compile a datafile. Print a C-scan map. Adjust controls as necessary topro
