Effect of Nanotwin Boundary on the Cu–Cu Bonding
Tsan-Feng Lu, Tung‐Yen Lai, Yi Yang Chu, YewChung Sermon Wu
Abstract
Cu direct bonding has been achieved at 120 °C by using (111)-oriented nanotwinned Cu because it has the fastest surface diffusivity. In this study, the effect of nanotwin boundary on the Cu bonding was investigated by using two types of (111)-oriented Cu films: sputtered 97% (111)-oriented Cu films and electroplated nano-twinned-Cu films. Artificial voids were introduced at bonded interfaces by bonding an etched-Cu sample to an unetched-Cu. The evolutions of interfacial voids were investigated at 150 °C and 200 °C. It was found that nanotwin boundary could enhance the transport of Cu atoms, thus enhance Cu–Cu direct bonding.
Topics & Concepts
Materials scienceCopperThermal diffusivityElectroplatingBoundary (topology)Composite materialMetallurgyThermodynamicsLayer (electronics)MathematicsPhysicsMathematical analysisElectronic Packaging and Soldering Technologies3D IC and TSV technologiesCopper Interconnects and Reliability