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1、Low Alpha Materials and Metrology in the IC Industry,Current Status and Future Requirements,http:/,Outline,Soft errors&IC developmentCurrent StatusMaterialsTypes Purity/Activity requirementsMetrologyAlpha emissivityInstrument capabilityFuture RequirementsMaterial specificationsChanges on the horizon
2、Purity/Activity requirements become more stringentMetrologyImprovements,Integrated Circuits and Soft Error Upsets,Energetic particles depositing energy/charge in critical nodesRadioisotopes in component materialsCosmic ray contributionsMicroelectronic design trends Flip Chip Smaller geometries/decre
3、asing line widthsIncreased vulnerability to soft error mechanisms,Soft errors=significant issue in the future,IC Materials Overview,High purity metals and alloysCu,Al,Ta,W,Ti,Pb,Sn,Ag,RuRange in purity from 99.99%to 99.9999%Alpha Activity Requirements0.02 hr1cm2:early 1990s0.01 hr1cm2:late 1990s0.00
4、2 hr1cm2:20010.0002 hr1cm2:2006Primary alpha emitters210Pb in Pb/Sn soldersU&Th,Material purity critical to reliability,Current Material Challenges:Contamination,Any material with U and/or Th above 1 ppbSome 99.99%materials failSn,InPossible contaminantsRefractory materials and ceramicsAbrasives Atm
5、ospheric dust and debrisCommercial metals&alloysAll stages of manufacturing&processing must be controlled&monitored,Assume any material is an alpha contamination hazard until proven otherwise,Current Instrumentation Capability,Industry uses Gas Proportional CountersArea:1000 cm2 Geometry:2Background
6、 2-3 cph optimal,4-6 nominalNo energy spectroscopy capabilityLimited ability to identify contamination sources0.002 analysis requires 7 days counting time for 20%RSD,Current instrumentation incapable of timely analysis,Ordela 8600,Alpha Sciences 1950,Precision/Counting Time trade off,Counting time d
7、etermined by detector size,Alpha counting rates relative to background,Solution:Increase signal and/or decrease noise,Background effect on counting time,Material Requirements-Future,0.001 hr1cm2 material in manufacturingTechnology roadmaps:0.0002 hr1cm2 in 20062 s from 1 square meter area per hour!W
8、ith current measurement technology this would take 228 days to measure with 20%relative precisionWhere is the specification bottom?Design dependentWhere influences other than cosmic are insignificantMeasurement times compatible with manufacturing schedules,Instrumentation improvement required,Instru
9、mentation for the Future,Measure increasingly low activity levels in timely manner without loss of precisionIncrease signal/noise ratioIncrease detector area without increasing background Optimum solution S/N requires background0.5 cphCurrent progressLarge area Si detectorsCr-39 hole countingLow bac
10、kground facilitiesEliminate cosmic componentEnable higher purity materials in detector constructionDecrease detector backgroundAssess detector qualityValidate production methods and materials,Significant opportunity for improvement,Best case scenario,Large area-Zero background-High precision,Conclus
11、ions,IC improvements continue to require lower activity materialsAs material activity decreases,contamination risk increasesCurrent instrumentation has significant limitationsLong analysis timesNo spectroscopic capabilityFuture activity specifications require more than incremental improvement in instrument capabilityUltra Low background instruments will be necessary to meet these specifications,
