AI-HPC - BBCube 3D - Heterogeneous 3D Integration to Provide TBs Bandwidth with Lowest Bit Access Energy for AI-HPC applications.pdf

1、OCP Global Summit October 18,2023|San Jose,CANorio ChujoIIR,WOW Alliance,Tokyo Institute of TechnologyResearch&Development Group,Hitachi,LTD.BBCube 3D:Heterogeneous 3D Integration to Provide TB/s Bandwidth with Lowest Bit Access Energy for AI/HPC applicationsMotivationDemands for high data bandwidth

2、 are increasingHBM has been introducedHigh bandwidth with the same power2D transmission prevents improvement of access energyHeterogeneous 3D integrationPaving the way to 10 TB/s0.11101001000100100010000Mem.access power WMemory bandwidth GB/sDDR(2D)100 W power budgetxPUPCBDIMMDDR0.111010010001001000

3、10000Mem.access power WMemory bandwidth GB/sDDR(2D)HBM(2.5D)100 W power budgetxPUHBM2EHBM2EHBM2EHBM2EHBM2EHBM2EHBM2EHBMSi interposer0.11101001000100100010000Mem.access power WMemory bandwidth GB/sDDR(2D)HBM(2.5D)Heterogeneous 3D100 W power budgetHBM2EHBM2EHBM2EHBM2EHBM2EHBM2EHBM2ExPUCachedieDRAMdies

4、Heterogeneous 3DI challengesMemories on top ofxPUxPU on top of memoriesStructureCoolingDifficultEasyPower DeliveryEasyDifficultDRAMxPUDRAMxPUBBCube 3DxPUEasyCoolingxPU cannot dissipate heat sufficientlyPower deliveryImpedance of TSV causes supply voltage drop and large droopBBCube has potential to s

5、olve 3DI issuesDense TSVsThin diesWaffle shaped waferxPU diesBase waferBase wafer(4)Litho,etching and liner deposition(5)Cu ECD and flattening by CMP(2)MoldingAdhesive(1)Attach face-down(3)Wafer thinningAdhesiveBase wafer(3)Wafer thinningAdhesiveBase waferProcess Flow of BBCube 3D(CoW)Process Flow o

6、f BBCube 3D(WoW)DRAM wafer(1)Wafer thinningCarrier waferAdhesive(temporary)(4)Cu ECD and flattening by CMP(3)Litho,etching and liner depoBase waferBase waferBase wafer(2)Bonding and debonding of carrier waferAdhesiveCarrier waferBumpless Via-Last interconnect similar to Cu/Low-k BEOL processStacking