Image formation using geometrical theory of diffraction and its applications to lithography

<P>PROPAGATING DIFFRACTED RAYS POSTULATED IN GEOMETRICAL THEORY OF DIFFRACTION THROUGH</P><P>THE OPTICAL SYSTEM AND COLLECTING THEM IN IMAGE SPACE, IT IS DISCOVERED THAT, IF THE</P><P>DIFFRACTED RAY FIELDS ARE SAMPLED ABOUT THE PENUMBRA REGIONS ABOVE SOME THRESHOLD</P><P>VALUE, 1D AND 2D IMAGE DISTURBANCES CAN BE CONSTRUCTED ENTIRELY FROM EDGE AND</P><P>VERTEX RAY CONTRIBUTIONS, RESPECTIVELY. BY REARRANGING THE MATHEMATICAL FORMULATION,</P><P>2D IMAGE DISTURBANCE CAN BE CONSTRUCTED FROM EDGE CONTRIBUTIONS AS WELL.</P><P>USING THE EDGE-BASED MODEL, WE DISCOVERED THAT IMAGING BEHAVIOR IS GOVERNED BY</P><P>A CHARACTERISTIC LENGTH. AND USING THE VERTEX-BASED MODEL, THE AMOUNT OF PREDISTORTION</P><P>NEEDED FOR OPTICAL PROXIMITY CORRECTION CAN BE SOLVED FROM A SYSTEM OF</P><P>LINEAR EQUATIONS. THE IMAGE DISTURBANCE OF 1D NON-PLANAR MASK OBJECT CAN BE OBTAINED</P><P>SIMILARLY. COMPARED WITH EXISTING METHODOLOGY WHERE THE EFFECTIVE OBJECT</P><P>FIELD IS PRE-CALCULATED USING A RIGOROUS ALGORITH

Author dc:creator

• KHOH KER CHING, ANDREW

• image formation theory, geometrical theory of diffraction, lithography, optical proximity correction, simulation