1、Designation:F 357 78(Reapproved 2002)Standard Practice forDetermining Solderability of Thick Film Conductors1This standard is issued under the fixed designation F 357;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last r
2、evision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice covers a procedure for determining thesolderability of thick-film conductors.The procedure has beenadapted from se
3、veral techniques that are in routine use fortesting this property.1.2 The values stated in inch-pound units are to be regardedas the standard.The values given in parentheses are forinformation only.1.3 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is
4、the responsibilityof whoever uses this standard to consult and establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Terminology2.1 Definition:2.1.1 solderabilitythe ability to accept or be wetted bysolder.3.Summary of Practice3.
5、1 Conductor ink is screened and fired onto a substrate bymeans of appropriate conventional screening techniques andfiring cycles.A sphere of the solder to be used is placed on thesurface of the fired conductor with an appropriate flux.Thesystem is heated to soldering temperature,maintained at thatte
6、mperature for a fixed time,and cooled rapidly.The solder-ability of the conductor is graded on the basis of the measureddiameter of the solder ball after it has passed through the heatcycle.4.Significance and Use4.1 The procedure of this practice is suitable for processcontrol.4.2 No interlaboratory
7、 precision has been established for theprocedure of this practice.Therefore,this practice should notbe used for the acceptance or rejection of material exchangedbetween buyers and sellers.5.Apparatus5.1 Electric Hot Plate(or other suitable heat source such asa bath of molten solder)with an area abou
8、t 6 by 6 in.(150 by150 mm)or larger,capable of maintaining a temperature 50 65C above the melting point of the solder under test.5.2 Cast Iron Plate,approximately 6 by 6 by12in.(150 by150 by 13 mm).NOTE1It is recommended that the plate be coated on all faces with a0.001 in.(0.03 mm),max,thickness of
9、 poly(tetrafluoroethylene)toprevent spilled solder from wetting and adhering to the plate.5.3 Surface Temperature Pyrometer with an accuracy betterthan 62%over the temperature range of the test.5.4 Chill Block of steel or aluminum approximately 6 by 6by 1 in.(150 by 150 by 25 mm).NOTE2If large quant
10、ities of parts are being tested,it is advantageousto water cool the chill block.5.5 Timer,capable of indicating a time interval of 30 s to thenearest 0.2 s.5.6 Machinists Microscope or microscope with calibratedmeasuring reticle capable of indicating diameters between0.010 and 0.050 in.(0.25 and 1.2
11、7 mm)with a resolution ofapproximately 0.0005 in.(0.013 mm).6.Materials6.1 Solder Balls,0.018 6 0.001 in.(0.46 6 0.03 mm)indiameter,in quantity,composition,and purity appropriate tothe conditions of the test(see 7.3).6.2 Flux appropriate to the solder-conduct or system undertest.6.3 Blank Substrates
12、 of suitable type and quantity(see 7.3)for the system under test.7.Test Specimen7.1 The test specimen shall be prepared by screeningconductor ink onto a substrate by means of conventionaltechniques and fired according to the desired cycle,as agreedupon by the parties to the test.It is recommended th
13、at thethickness of the fired conductor be 0.0005 in.(0.013 mm)orgreater and that the minimum width be 0.08 in.(2.0 mm).1This practice is under the jurisdiction of Committee F01 on Electronics and isthe direct responsibility of Subcommittee F01.03 on Metallic Materials.Current edition approved Dec.10
14、,2002.Published May 2003.Originallyapproved in 1972.Last previous edition approved in 1997 as F 35778(1997)e1.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.7.2 Alternatively the specimen to be tested may be selectedfrom a batch of fired
15、 conductors according to proceduresagreed upon by the parties to the test.7.3 Due to the qualitative nature of this test and to randomvariations in materials,a single test can give misleading results.Therefore,a statistically valid sample should be employed.Atotal of 30 measurements obtained from 10
16、 substrates eachcontaining 3 solder balls is recommended.8.Procedure8.1 Place the cast iron plate on the hot plate.8.2 Place a blank substrate on the cast iron plate and placethe surface temperature pyrometer on top of the blank sub-strate.8.3 Heat the hot plate until the surface temperature pyrom-eter indicates that a stable temperature 50 6 5C above themelting point of the solder to be tested has been maintained forat least 5 min.8.4 Apply an appropriate flux to the surface of the firedconduct
