Effect of flip chip bonding parameters on microstructure at the interconnect interface and shear properties of 64.8Sn35.2Pb microbumps were investigated in this work.Results show that the main intermetallic compound(I...Effect of flip chip bonding parameters on microstructure at the interconnect interface and shear properties of 64.8Sn35.2Pb microbumps were investigated in this work.Results show that the main intermetallic compound(IMC)at the interconnect interface is(Ni,Cu)_(3)Sn_(4)phase,and meanwhile a small amount of(Cu,Ni)_(6)Sn_(5)phase with a size of 50−100 nm is formed around(Ni,Cu)_(3)Sn_(4)phase.The orientation relationship of[-1-56](Ni,Cu)_(3)Sn_(4)//[152](Cu,Ni)_(6)Sn_(5)and(601)(Ni,Cu)_(3)Sn_(4)//(-201)(Cu,Ni)_(6)Sn_(5)is found between these two phases,and the atomic matching at the interface of the two phases is low.The highest shear force of 77.3 gf is achieved in the 64.8Sn35.2Pb microbump at the peak temperature of 250℃and parameter V1 because dense IMCs and no cracks form at the interconnect interface.Two typical fracture modes of microbumps are determined as solder fracture and mixed fracture.The high thermal stress presenting in the thick IMCs layer induces crack initiation,and cracks propagate along theα/βphase boundaries in the Sn-Pb solder under shear force,leading to a mixed fracture mode in the microbumps.展开更多
Metallurgical challenges in controlling the microstructural stability of Cu and solder microbumps in 3D IC packaging technol-ogy are discussed. Using uni-directional 【111】 oriented nanotwinned Cu, the controlled gro...Metallurgical challenges in controlling the microstructural stability of Cu and solder microbumps in 3D IC packaging technol-ogy are discussed. Using uni-directional 【111】 oriented nanotwinned Cu, the controlled growth of oriented Cu6Sn5 on the nanotwinned Cu and its transformation to Cu3Sn without Kirkendall voids have been achieved. In order to join a stack of Si chips into a 3D device, multiple reflows of solder microbumps may be required; we consider localized heating to do so by the use of self-sustained explosive reaction in multi-layered Al/Ni thin films of nano thickness. It avoids re-melting of those solder joints which have been formed already in the 3D stacking structure.展开更多
基金Project(U2341254)supported by Ye Qisun Science Foundation of National Natural Science Foundation of ChinaProject(52475406)supported by the National Nature Science Foundation of ChinaProject(2024CY2-GJHX-32)supported by the Key R&D Program of Shaanxi Province,China。
文摘Effect of flip chip bonding parameters on microstructure at the interconnect interface and shear properties of 64.8Sn35.2Pb microbumps were investigated in this work.Results show that the main intermetallic compound(IMC)at the interconnect interface is(Ni,Cu)_(3)Sn_(4)phase,and meanwhile a small amount of(Cu,Ni)_(6)Sn_(5)phase with a size of 50−100 nm is formed around(Ni,Cu)_(3)Sn_(4)phase.The orientation relationship of[-1-56](Ni,Cu)_(3)Sn_(4)//[152](Cu,Ni)_(6)Sn_(5)and(601)(Ni,Cu)_(3)Sn_(4)//(-201)(Cu,Ni)_(6)Sn_(5)is found between these two phases,and the atomic matching at the interface of the two phases is low.The highest shear force of 77.3 gf is achieved in the 64.8Sn35.2Pb microbump at the peak temperature of 250℃and parameter V1 because dense IMCs and no cracks form at the interconnect interface.Two typical fracture modes of microbumps are determined as solder fracture and mixed fracture.The high thermal stress presenting in the thick IMCs layer induces crack initiation,and cracks propagate along theα/βphase boundaries in the Sn-Pb solder under shear force,leading to a mixed fracture mode in the microbumps.
文摘Metallurgical challenges in controlling the microstructural stability of Cu and solder microbumps in 3D IC packaging technol-ogy are discussed. Using uni-directional 【111】 oriented nanotwinned Cu, the controlled growth of oriented Cu6Sn5 on the nanotwinned Cu and its transformation to Cu3Sn without Kirkendall voids have been achieved. In order to join a stack of Si chips into a 3D device, multiple reflows of solder microbumps may be required; we consider localized heating to do so by the use of self-sustained explosive reaction in multi-layered Al/Ni thin films of nano thickness. It avoids re-melting of those solder joints which have been formed already in the 3D stacking structure.
