Ultra-thin　siliconwafer　is　highly　demanded　by　semi-conductor　industry.　During　wafer　thinning　process,　the　grinding　technology　will　inevitably　induce　damage　to　the　surface　and　subsurface　of　silicon　wafer.　To　understand　the　mechanism　of　subsurface　damage　(SSD)　layer　formation　and　mechanical　properties　of　SSD　layer,　atomistic　simulation　is　the　effective　tool　to　perform　the　study,　since　the　SSD　layer　is　in　the　scale　of　nanometer　and　hardly　to　be　separated　from　underneath　undamaged　silicon.　This　paper　is　devoted　to　understand　the　formation　of　SSD　layer,　and　the　difference　between　mechanical　properties　of　damaged　silicon　in　SSD　layer　and　ideal　silicon.　With　the　atomistic　model,　the　nano-grinding　process　could　be　performed　between　a　silicon　workpiece　and　diamond　tool　under　different　grinding　speed.　To　reach　a　thinnest　SSD　layer,　nano-grinding　speed　will　be　optimized　in　the　range　of　50-400　m/s.　Mechanical　properties　of　six　damaged　silicon　workpieces　with　different　depths　of　cut　will　be　studied.　The　SSD　layer　from　each　workpiece　will　be　isolated,　and　a　quasi-static　tensile　test　is　simulated　to　perform　on　the　isolatedSSDlayer.　The　obtained　stress-strain　curve　is　an　illustration　of　overall　mechanical　properties　of　SSD　layer.　By　comparing　the　stress-strain　curves　of　damaged　silicon　and　ideal　silicon,　a　degradation　of　Young＇s　modulus,　ultimate　tensile　strength　(UTS),　and　strain　at　fracture　is　observed.　(C)　2018　Author(s).