Flipchip工藝流程

1、1.Metal bump 金屬凸塊-C4 process(IBM)2. Tape-Automated bonding 捲帶接合-ACF process3. Anisotropic conductive adhesives 異方向性導電膠 -ACP process4.Polymer bump 高分子凸塊 - C4 process5.Stud bump. 打線成球 - ACP process(Matsushita)Flip Chip conductive method - connect to Substrate/PCBC4: controlled collapse chip connection

2、ACF: anisotropic conductive filmACP(ACA): anisotropic conductive Adhesive pasteVarious flip chip technologiesSubstrateICICICICICICPads onsubstrateWirebondSolderConductiveadhesiveWITNiPolymerAuOvercoatSolderbumpNi/AubompElastomerTABLeadFluxless solder bumpPad onchipConductiveparticlesThermosettingadh

3、esiveSolder bumpUnderfillencapsulantPS: WIT ( Wire interconnect technology)TAB(Tape- automated bonding)Various flip chip technologiesICBumpSubstrateConductive pasteUnder fillElectrodeSBB(Stud Bump Bonding)ICBumpSubstrateSolderGBS(Gold Bump Soldering)ICAuBumpSubstrateAuElectrodeGGI(Gold to Goldinterc

4、onnection)IC BumpSubstrateAnisotropicconductivefilmACF/ACP(Anisotropic Conductive Film/Paste)ICSolderBumpSubstrateSolderC4/FCA(Controlled Collapse ChipConnection/Flip Chip Attach)IC BumpSubstrateUtraviolet-curedabhesiveMBB(Micro Bump Bonding)ICICSubstrateICSubstrateStud BumpFlip Chip BondUnderfill C

5、ure ovenCure ovenSBB ProcessC4: Controlled Collapse Chip Connection ProcessReflow ovenFlip chip bonderFlux cleanerUnderfill dispenserCure oven1. Flux coating or re-printing2. MountingHeatingCleaningDispensingHeatingWafer bumpBump by solderACP: Anisotropic Conductive Paste ProcessReflow ovenFlip chip

6、 bonderUnderfill dispenserCure ovenThermosettingDispensingHeating1. Print the ACA 2. AlignmentWafer bumpBump by AgACF: Anisotropic Conductive Film ProcessACF Pre-setterFlip chip bonderPress and cure equipmentACF Pre-setting1. Mounting2.Heating3.Press1.Heating2.PressWafer bumpBump by AuOvercoat with

7、polymide and open the bump areas.Pattern wettable base metalCoat chip with polymide, open vias over each padUsed dry-film lift-off process to define base metal and solder on each padPattern aluminum to re-route I/O to on area arrayConventional chip with aluminum I/O pads around the perimeterTack,Flu

8、x & ReflowPrint,Place & ReflowFCT Bump StructureSilicon waferUBM-Under Bump MetallurgySolder BumpFinal Metal PadDie PassivationWafer Bump1. 蒸鍍 Evaporation 2. 濺鍍 Sputter 3. 電鍍 Electroplating4. 印刷 Printed solder paste bump5. 錫球焊接 Solder ball bumping or Stud bump bonding (SBB)6.無電鍍鎳 Electroless nickel

9、technologiesMetal bump methodUBM1.95Sn/5Pb,97Sn/3Pb 高溫錫鉛合金2. 63Sn/37Pb 低溫錫鉛合金3. Ni 鎳4. Au 金 5.Cu 銅Material of solder bumpSilicon Wafer arrives with an aluminum based final metal pad and die passivation. Wafer can be probed prior to bumping.Wafer bump (Printed method) Process:Wafer clean The Under Bu

10、mp Metallurgy is added by FCT through sputtered layers of Al,Ni-V,&CuWafer Bump (Printed method) Process: Sputter UBMAl/Ni/Cu(Au)UBM consist 3 layer:1. Adhesion layer : Ti,Cr,TiW 提供鋁墊(Al pad)與護層(Passivation layer)有較強之黏著性2. Wetting layer:Ni,Cu,Mo,Pt 高溫迴焊時錫球可完全沾附而成球3. Protective layer:Au 保護 Ni,Cu等免於被氧

11、化.Wafer Bump (Evaporation method)Process: Sputter UBMApply photoresist, Pattern and develop Wafer Bump (Printed method) Process:Photo-resistEtch to form UBM capWafer Bump (Printed method)Process: Etch UBMDeposit solder paste and reflow to form bumpWafer Bump (Printed method) Process: Print solder pa

12、ste & reflowSn/Pb 63/37 低溫95/5高溫Sample measure bump height, bump shear and bump resistance.Wafer Bump (Printed method)Process: Inspection1. Evaporative bumps are 125 mils in diameter and 100 mils high.2. Plated bumps are 125 - 175 mils in diameter and 25 -100 mils high.The typical size of a bump bef

13、ore reflow :Process:Inspect wafer ChipBumpSubstrate/ModuleC4 processACF & ACP 1. Bump alloy type2.Solder joint height(standoff)3. Distance to neutral point or DNP.(A measurement of the center of mass of the die to the farthest bump on the die, typically the corner bump.) Evaporative solder bumping processWafer cleanEvaporation of UBM through metal maskEvaporation of high Pb solder through maskReflow to form solder ballA.B.C.D.95Pb/SnUBM:Cr/Cr-Cu/Cu/AuPolymide passivationElectroplated UBM w/ solder bumping processSputtered UBMApply photoresist,pattern and developApply2nd la