Silver　nanoparticle　(Ag　NP)　pastes　become　a　potential　die-attachment　material　with　the　increased　electronic　power　density.　However,　the　weakness　of　bonding　interface　between　sintered　Ag　NPs　and　bare　Cu　substrate　limits　the　applications　of　the　Ag　NPs　paste,　thereby　reducing　the　shear　strength　of　the　sintered　joint.　In　this　work,　ultrafast　laser　processing　is　utilized　to　enhance　the　bonding　strength　of　the　sintered　Ag　joint　by　fabricating　a　microstructure　interface.　The　microstructure　dimensions　are　tunable　by　controlling　laser　parameters,　and　then　high-strength　joints　could　be　obtained.　Different　substrate　microstructures　were　constructed,　and　the　enhanced　bonding　mechanism　was　analyzed　by　characterizing　the　cross　section　and　fracture　surface　morphologies　of　joints.　The　ultrafast　laser　processing　could　increase　the　surface　energy　of　Cu　substrates　to　form　a　more　reliable　connection　with　Ag　NPs　and　more　energy　required　for　crack　extension　with　the　increasing　connection　area,　thereby　resulting　in　a　significant　improvement　in　the　shear　strength　of　the　Ag　NP　joints.　The　patterned　microstructures　on　the　Cu　substrate　using　this　technique　showed　improved　surface　energy　and　increased　number　of　connection　areas　on　the　substrate,　showing　potential　for　the　use　in　third-generation　semiconductors　for　highly　reliable　packaging.