As　semiconductor　feature　sizes　continue　to　shrink,　the　allowable　error　margins　for　Critical　Dimension　(CD)　is　getting　increasingly　tight.　However　multiple　errors　are　inherent　in　the　lithography　system　which　could　have　severe　impact　on　CD　control　and　process　latitude.　It　is　indispensable　to　analyze　and　balance　the　influences　of　various　errors　in　order　to　get　larger　tolerance　for　errors　within　allowable　error　margins　for　CD.　In　this　paper,　by　using　PROLITHTM　X3　and　in-house　software　IntLitho,　we　study　the　cross-talk　of　the　dominative　errors　of　numerical　aperture,　coherent　factors,　mask　CD,　flare　and　analyze　its　influence　on　lithography　performance.　The　results　show　that　the　tolerance　for　the　errors　can　be　released　when　some　errors　impact　on　CD　is　counterpoised　by　that　arising　from　another　error　in　usable　process　window.　Moreover　multiple　combinations　of　errors　or　tolerances　can　be　used　for　such　compensations.　Finally　we　supply　a　method　to　perform　the　compensation　of　multi　errors　impact　on　CD　and　process　window,　which　is　the　essence　of　co-design　or　co-optimization　of　lithography　tool　for　rigorous　CD　control.