Patent ID: 6432832
Filing Date: 2002-08-13
Classification: H01L,Y10S

Abstract:
In a plasma processing chamber, a method of performing a shallow trench isolation etch in a silicon layer, said silicon layer being disposed below a pad oxide layer, said pad oxide being disposed below a nitride layer, said nitride layer being disposed below a photoresist mask, said method comprising:flowing a first etchant source gas into said plasma processing chamber; forming a first plasma from said first etchant source gas; etching through said nitride layer with said first plasma; flowing a second etchant source gas into said plasma processing chamber; forming a second plasma from said second etchant source gas; substantially removing said photoresist mask with said second plasma, wherein a substantial portion of said photoresist mask is removed from above said nitride layer before said silicon layer; flowing a third etchant source gas into said plasma processing chamber; forming a third plasma from said third etchant source gas; etching through said pad oxide layer and substantially stopping on said silicon layer, wherein a portion of the nitride layer is etched during the pad oxide etch; flowing a fourth etchant source gas into said plasma processing chamber; forming a fourth plasma from said fourth etchant source gas; and etching through said silicon layer with said fourth plasma, said etching forming a narrow feature and a wide feature in said silicon layer, and wherein a first profile angle of said narrow feature is substantially equal to a second profile angle of said wide feature.