ASTM_F_508_-_77_2002.pdf

Designation:F 508 77(Reapproved 2002)Standard Practice forSpecifying Thick-Film Pastes1This standard is issued under the fixed designation F 508;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 practice covers the writing of specifications forthick-film pastes for electronics.1.2 The practice provides a guide for the routine procedureto be followed in specifying for procurement thick-film pastesfor use in manufactured circuits.Specific requirements,in-tended applications,and test methods should be included oridentified in each paste specification.In addition,each speci-fication should include basic information to facilitate procure-ment,preparation,quality control,lot shipment identifications,and shipping of such pastes.1.3 The practice covers the development of specificationsfor fireable,thick-film pastes,including resistor,conductor,dielectric,and overglaze pastes.2.Specification Form and Content2.1 FormEach specification should be prepared in con-formance with Form and Style for ASTM Standards.22.2 Procurement InformationInformation pertinent toprocurement should include the procuring organizationsname,location,address,telephone number,and the name of theprocurement agent,or anyone else involved in procurement orwith the technical details of the specifications.2.3 Technical InformationEach specification should coverthe specific technical details,the performance requirements,and the precision or accuracy of measurements necessary forthe producer to supply the thick-film paste specified.2.3.1 Processing Characteristics:2.3.1.1 Screen SelectionThe particular paste specifica-tions should identify the required screen by the mesh count,thewire size,and the emulsion thickness.Where metal masks areto be used,the cavity thickness and the cavity-aperturetolerances should be specified.The specification should alsostate the recommended nominal deposit thickness.2.3.1.2 Drying and Leveling CharacteristicsThe specifi-cation should state the range of drying time,the range of dryingtemperature,and the dried film(leveling)characteristics.Thedried film characteristics may be specified by visual examina-tion,for such defects as lifting or pinholes,and by a thicknessprofile across the surface of the dried film.2.3.1.3 Firing ProfileThe specification profile for eachspecific style of paste.2.3.1.4 Firing AtmosphereFor each style of paste andfiring profile,the specification should define the firing atmo-sphere.2.3.1.5 Test SubstrateThe specification should specifyand identify the composition of the test substrate and thesurface on which the paste is to be deposited.2.3.2 Test PatternWhere applicable,the specificationshould include a layout and description of a suitable test patternfor evaluating printed and fired pastes.The specification shouldalso include a list and functions of other materials required toperform the specified tests,that is,terminations,leads,etc.Consideration should be given to compatibility requirementsfor all materials used.2.4 Quality ControlThe specification should identify thequality control procedures to be employed.Such proceduresshould include:a sampling plan,a sequence for each exami-nation and test specified,and corresponding requirements foreach method of examination or test.2.5 Handling and StoringEach specification should in-clude the method of handling and storing the pastes.2.6 Performance Tests:2.6.1 Individual procurement specifications should includerequirements for each selected applicable test,inspection,andexamination listed in Table 1 and Table 2 for the given type ofthick-film paste.The specification should include any otherpertinent tests and inspections to cover special or specificapplications.2.6.1.1 The test and inspection equipment specified shouldbe of sufficient accuracy and quality to permit the required testsand inspections to be carried out.2.6.1.2 The types of visual inspection equipment to be usedshould be specified,including magnification(to be givenseparately for the objective and eyepiece if both are used),thetype of light,the intensity,and the direction of the light source.2.6.1.3 For fired materials,the inspection criteria shouldspecify the general surface appearance.The number,location,and maximum size of permissible significant defects such aspinholes,projections,scratches,and surface contamination1This practice is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.03 on Metallic Materials.Current edition approved Dec.10,2002.Published May 2003.Originallyapproved in 1991.Last previous edition approved in 1997 as F 508 77(1997)e1.2Available fromASTM,100 Barr Harbor Drive,West Conshohocken,Pa.19428.1Copyright ASTM International,100 Barr Harbor Drive,PO