Research On The Within-wafer Thickness Uniformity Of The Inter-metal Dielecric Layer

The research focuses on the within-wafer thickness uniformity of the Inter-Metal Dielectric(IMD)layer which is one of the key parameters during integrated circuit manufacturing.The within-wafer thickness uniformity of IMD layer can be improved with the optimization of Chemical Vapor deposition(CVD),Chemical Mechanical Polishing(CMP)and process integration.The optimum within-wafer thickness uniformity is 0.48%in the Plasma Enhanced CVD(PECVD)design of experiment(DOE)by tuning the distance between the shower head and heater and wafer position on the heater.The optimum within-wafer thickness uniformity is 2.11%in HDPCVD DOE by tuning top Si H₄ gas flow and side Si H₄ gas flow.Based on DOE and actual CMP process requirements,the within-wafer Removal Rate(RR)thickness uniformity can be optimized to 2.01%by tuning down force pressure and platen rotate speed.The IMD within-wafer thickness uniformity is improved from 12.8%to 4.07%and the yield is improved about 5%?10%by additional HDPCVD film which thickness is thinner at wafer center and thicker at wafer edge to fix the issue about PECVD film which thickness is thicker at wafer center and thinner at wafer edge and air gap broken after CMP process.This research can enlarge the process window and improve product yield by within-wafer thickness uniformity of IMD layer improvement.