Nowadays,　the　mainstream　way　of　dicing　SiC　is　diamond　or　wire　saw　dicing,　which　has　low　dicing　efficiency　and　high　dicing　loss.　The　edges　of　the　cuts　all　have　different　degrees　of　chipping　and　incompleteness.　Thus,　the　existing　diamond　mechanical　cutting　process　is　one　of　the　factors　limiting　the　development　of　SiC　semiconductor　process.　Femtosecond　laser　is　considered　as　an　alternative　to　mechanical　cutting　because　of　its　non-contact,　high　precision　and　how　heat-affected　zone　processing　characteristics.　In　this　paper,　we　take　advantage　of　the　high　penetration　of　the　infrared　laser　to　focus　the　femtosecond　laser　beam　to　form　a　modified　layer　inside　the　SiC.　Then　the　separation　of　the　wafers　is　achieved　with　the　help　of　mechanical　means.　Scanning　electron　microscopy　(SEM)　was　used　to　observe　the　microstructure　of　the　modified　layer.　Raman　spectrograms　are　used　to　characterize　mechanical　features　such　as　component　changes　and　residual　stresses　in　the　modified　layer.　Different　laser　parameters　such　as　laser　power　and　pulse　width　have　an　important　influence　on　the　modified　layer.　It　further　affects　the　ease　of　separating　the　wafers　and　the　quality　of　the　cross　section.　The　increase　in　pulse　width　facilitates　the　formation　of　modified　layers　inside　the　SiC　by　ranging　from　250fs　to　5ps.　This　is　because　when　the　pulse　width　is　small,　the　self-defocusing　effect　from　too　high　plasma　density　cannot　produce　a　stable　modified　layer　inside　the　SiC.　Different　energy　densities　form　a　large　difference　in　the　size　of　the　internal　modification　zone　of　SiC.