Reduction of Critical Dimension Difference in Litho-Etch-Litho- Etch Double Patterning Process

The successful implementation of double patterning lithography in semiconductor manufacturing is dependent on the progress of several key items, including good control of critical dimension (CD) uniformity and overlay. Here we report a pass-to-pass post-etch CD (ECD) difference in Litho-Etch-Litho- Etch (LELE) process. The CD difference mainly came from the organic planarization layer (OPL) thickness delta between 1st pass Litho-Etch (LE) process and 2nd pass LE process. The pass-to-pass CD difference can be reduced by adjusting the OPL thickness.