Manufacturing And Reliability Challenges With QFN - SMTA

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Reliability (Thermal Cycling)• Order of magnitude reduction in time tofailure from QFP3X reduction from BGAQFP: >10,000• Driven by die / package ratio 40% die; tf = 8K cycles (-40 / 125C) 75% die; tf = 800 cycles (-40 / 125C)• Driven by size and I/O# 44 I/O; tf = 1500 cycles (-40 / 125C) 56 I/O; tf = 1000 cycles (-40 / 125C)• Very dependent upon solder bond withthermal padBGA: 3,000 to 8,000QFN: 1,000 to 3,000© 2004 - 200939
Thermal Cycling (ConformalCoating)• Care must be taken when using conformal coating over QFNCoating can infiltrate under the QFNSmall standoff height allows coating to cause lift• Hamilton Sundstrand found a significant reduction in time tofailure (-55 / 125C)Uncoated: 2000 to 2500 cyclesCoated: 300 to 700 cycles• Also driven by solder jointsensitivity to tensile stressesDamage evolution is farhigher than for shear stressesWrightson, SMTA Pan Pac 2007© 2004 - 200940
Page 4 and 5: Who Uses DfR?Military / Avionics /
Page 6 and 7: Knowledge and Education(Website)•
Page 8 and 9: Introduction (cont.)• Why is know
Page 10 and 11: Component Packaging• Most of us h
Page 12 and 13: 2 nd Level Interconnect Reliability
Page 14 and 15: Solder Wearout (cont.)• Eliminati
Page 17 and 18: Industry Response to SJ Wearout?•
Page 19 and 20: Quad Flat Pack No-Lead (QFN)© 2004
Page 21 and 22: QFN (cont.)• Availability 1 x 2 m
Page 24 and 25: Advantages: Thermal Performance•
Page 26 and 27: QFN: Why Not?• QFN is a ‘next g
Page 28 and 29: Bond Pads (cont.)• Extend bond pa
Page 30 and 31: Singulated operationTitle: Reliabil
Page 32 and 33: Title: Reliability study of surface
Page 34 and 35: Manufacturability (Rework)• Can b
Page 36 and 37: Manufacturability (cont.)• QFN so
Page 40 and 41: Reliability (Bend Cycling)• Low d
Page 42 and 43: Dendritic Growth (cont.)• The ele
Page 44: QFN: Risk Mitigation• Assess manu

Manufacturing And Reliability Challenges With QFN - SMTA

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