Advanced CMP conditioning for front end applications

In this paper, the performance of a metal free novel microreplicated pad conditioner, 3M™ Trizact™ Pad Conditioner, B5-M990-5S2, consisting of precisely engineered microreplicated abrasive structures coated with a chemical vapor deposited (CVD) diamond film is demonstrated for Front End of Line (FEOL) silicon-on-insulator (SOI) application. Extended polish marathon testing of baseline thermal oxide films used as precursors for patterning in SOI applications was conducted to compare conditioning performance of the microreplicated conditioner versus the conventional diamond grit (DG) disk on an AMAT Mirra® polishing tool platform. Thermal oxide removal rate (TOX RR) values were comparable between the disks. However, the microreplicated disk exhibited less RR variation, better uniformity and flatter TOX RR profiles of the remaining films compared to the profiles generated with the grit disk. Laser groove depth analysis (LGDA) of the pads after marathon testing showed higher surface finish and higher pad wear rates with the pads used with the grit disk. SP1 (KLA/Tencor) light point defect (LPD) measurements on the wafers run with the grit disk showed a defectivity spike at POR pad life of 350-400 wafers. There was no spike observed with the microreplicated disk. The microreplicated disk was run up to 3500 wafers.