ASTM_F_692_-_97_2002.pdf

Designation:F 692 97(Reapproved 2002)Standard Test Method for MeasuringAdhesion Strength of Solderable Films to Substrates1This standard is issued under the fixed designation F 692;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the adhe-sion strength of films to substrates by pulling wires soldered tothe films.1.2 This test method is intended to measure the adhesion ofmetallization to substrates,and not the strength of the solder.1.3 This test method applies to all films that can be soldered.1.4 The maximum melting point of solder used with this testmethod is determined by the characteristics of the solder flux.1.5 This test method is destructive.1.6 This standard does not purport to address the safetyconcerns,if any,associated with its use.It is 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 Definitions of Terms Specific to This Standard:2.1.1 solder failurein microelectronics,a failure mode inwhich the wire tears through the solder.2.1.2 solder interface failurein microelectronics,a failuremode in which most of the solder is removed from the film andno detectable amount of film is removed from the substrate.3.Summary of Test Method3.1 Test specimens,each consisting of a substrate uponwhich a pattern of square test films,are prepared usingequipment,materials,and procedures typical of the process tobe evaluated.Specimens are pre-tinned;wires are centeredover test pads and held in place with a fixture of low thermalmass.Specimens and wires are then soldered using controlledamounts of solder and flux and controlled heating followed bya 24-h period for stress relaxation.A soldered wire is bent at aright angle from each substrate.The substrate is then restrainedand supported in an appropriate fixture,and the wire is attachedto a lifting mechanism by a grip.The grip and substrate holderare moved apart until the wire is pulled off the substrate.Theforce applied in order to cause separation is recorded.Themode of failure is observed and recorded.3.2 The solder alloy used is not specified by the test method,and shall be agreed upon by the parties to the test.3.3 The flux used is not specified by the test method,andshall be agreed upon by the parties to the test.4.Significance and Use4.1 Failure of hybrid microcircuits is often due to failure ofa solder bond.The limiting strength that can be obtained for asolder bond is often the adhesion of the soldered film to thesubstrate.4.2 This test method can be used for material selection,process development,research in support of improved yield orreliability,and specification for material procurement.4.3 It is not recommended that this test method be used indeciding questions between buyers and sellers until the preci-sion of the method has been determined by interlaboratorycomparison.5.Interferences5.1 If the angle between the direction of the lifting force andthe top surface of the substrate differs from a right angle bymore than 5,the force measured may differ significantly fromthat required to achieve operation with a perpendicular con-figuration.5.2 Visible irregularities in the motion of the lifting mecha-nism may introduce extraneous forces and thus invalidate thetest.5.3 The presence of vibration or mechanical shock maycause the application of an extraneous force and thus invalidatethe test.5.4 Each specimen presents a thermal mass to the heatingapparatus.Changes in substrate thickness will require a rede-termination of the time temperature profile.5.5 Changes in melting points when using different solderalloys also require a redetermination of the time temperatureprofile.6.Apparatus6.1 Bond-Pulling MachineApparatus for measuring theadhesion pull strength,incorporating the following compo-nents:1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.03 on MetallicMaterials.Current edition approved Dec.10,2002.Published May 2003.Originallyapproved in 1980.Last previous edition approved in 1997 as F 69297.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.6.1.1 Gripping Means to attach the wire to the liftingmechanism.6.1.2 Lifting and Gaging Mechanism for applying a mea-sured vertical force to the gripping means with respect to thesubstrate holder.The mechanism shall incorporate a means forrecording the maximum force applied within 0.5 N and shall becapable of moving at a rate of at least 13 mm/min.6.1.3 Stereoscopic Microscope with Light Source having amagnification of approximately