Three　nano-Ag　films　with　different　particle　size　distribution　were　fabricated　as　die-attach　materials　by　pulsed　laser　deposition　(PLD)　using　nanosecond　(ns),　picosecond　(ps),　and　femtosecond　(fs)　lasers.　The　effects　of　interface　bonding　of　the　three　films　on　shear　strength　and　fracture　behaviors　were　systematically　studied.　The　investigation　of　the　interfacial　neck　growth　mechanism　of　the　PLD　films　with　different　particle　size　provided　insight　into　the　formation　process　of　the　bonding　interface.　The　results　showed　that　when　the　laser　pulse　duration　decreased　from　ns　to　fs,　the　average　particle　size　decreased　and　the　shear　strength　of　the　joints　increased　significantly.　The　fs-film　presented　extremely　high　shear　strength　of　147 MPa　at　250°C,　3.2　times　and　2.0　times　higher　than　the　ns-film　(46 MPa)　and　the　ps-film　(75 MPa),　respectively,　and　well　above　most　reports.　The　interface　connection　ratio　was　the　dominant　factor　affecting　shear　strength　and　fracture　behaviors.　The　interfacial　neck　growth　of　the　fs-film　was　much　faster　than　the　ns-film　due　to　its　high　surface　and　grain　boundary　energy.　At　the　later　sintering　stage,　the　high　grain　boundary　energy　of　the　fs-film　drove　the　neck　merging　and　eliminated　the　gaps　between　the　necks,　resulting　in　the　high　interface　connection　ratio.　The　investigation　of　the　interfacial　neck　growth　mechanism　can　provide　new　guidance　for　interface　bonding　enhancement.　Graphical　Abstract:　[Figure　not　available:　see　fulltext.]　©　2023,　The　Minerals,　Metals　&　Materials　Society.