Array center and array corner loading effect improvement in r-SADP

Reverse Self-aligned Double Patterning (r-SADP) process is a very important technique in trench etching of Dynamic Random Access Memory devices. In the r-SADP etching process, due to the distinct etching environments at the center and corner of the array, there are differences in the etched trench critical dimension at the center and corner, which will adversely affect the performance and yield of the device. This paper investigates the impact of pressure, source power, and gas during the carbon etch-back (C-EB) step in the r-SADP process on the loading effect observed at both the center and corner of the array. The results indicate that applying high pressure during the C-EB over etching step can effectively alleviate the loading effect at the center and corner of the array in the r-SADP process.