As　the　next　generation　of　die　attachment　technology,　sintering　bonding　using　silver　nanoparticles　is　attracting　great　interest　for　application　in　power　electronics　packaging.　For　organic-free　silver　nano-sintering　materials,　increasing　the　oxygen　content　facilitates　the　sintering　process　but　also　causes　oxidation　of　the　substrate　and　other　components.　In　this　work,　organic-free　silver　nanostructured　film　was　utilized　to　bond　the　SiC　chips　and　the　substrate　with　three　types　of　metallization:　(1)　electroless　nickel　immersion　gold　finishing　substrate　(ENIG),　(2)　Ag-coated　substrate,　and　(3)　bare　Cu　substrate.　The　bonding　process　was　conducted　at　low　temperature　(150–300°C),　and　the　effects　of　oxygen　on　the　microstructure,　bonding　quality　of　the　interfaces　and　fracture　morphology　were　studied.　Oxygen　significantly　facilitated　the　sintering　process　of　the　Ag　nanoparticles　in　the　film,　which　promoted　the　densification　of　the　bondline,　even　at　low　concentrations　(0.05%).　In　addition,　the　facilitating　effects　of　oxygen　were　detected　at　content　of　0.05%　during　the　sintering　between　Ag　nanoparticles　and　the　three　types　of　metallized　substrate.　However,　at　higher　oxygen　content　(≥5%),　the　sintering　behavior　varied　among　the　different　substrate　metals.　The　Ag-coated　substrate　surface　roughened　in　situ　at　high　oxygen　content　and　showed　positive　effects　on　the　bonding　strength,　while　the　ENIG　substrate　surface　was　inert　to　oxygen.　The　bare　Cu　substrate　surface　showed　complex　oxide　states　at　different　oxygen　concentrations.　The　Cu2O　phase　formed　at　oxygen　content　of　≤　5%,　which　enhanced　the　bonding　strength,　while　CuO　tended　to　appear　at　oxygen　content　of　≥　20%,　which　reduced　the　bonding　strength.　These　results　reveal　that　relatively　low　oxygen　content　(0.05%)　can　effectively　improve　bonding　strength　while　avoiding　oxidation　of　the　Cu　substrate.　©　The　Minerals,　Metals　&　Materials　Society　2024.