Method to Improve the Definition of the Edges of Mask Patterns
Original Publication Date: 1988-Jul-01
Included in the Prior Art Database: 2005-Feb-15
It is sometimes difficult to control the chromium on quartz masks which are extensively used in the semiconductor processing, either visually or during image size measurement because of the poor definition of the edges of the mask patterns. Such a poor definition results in the detection of so great a number of defects that the control is no longer possible in the first case. In the second case, the measuring steps lead to unreliable results. It is, therefore, recommended the pattern delineated at the chromium/quartz interface be cleaned to etch a thin superficial layer of quartz about 200 o thick. When reactive ion equipment is used, a CF4 + C3F8 + 02 atmosphere and an etching duration of about 5 mm are appropriate operating conditions.