Process Development Of NMC Etching Equipment On The Shallow Trench Isolation And Its Application On Mass Production

For a long term,China's integrated circuit industry relies heavily on imports from manufacturing technology to equipment to material.The national integrated circuit "13th five-year plan" clearly puts forward the key development of domestic key technology equipment massive application.Take this opportunity,the domestic North Microelectronics Company(NMC)gradually grows stronger,and break the monopoly of foreign manufacturers in the application of the key process equipment of the gate etching and shallow trench isolation etching.It successfully achieve technical mass production at 55 nm node.This paper mainly described the development and mass production of 55 nm shallow trench isolation etch based on NMC612 12 inch platform.In the early stage of process development,the creativity technology of 55 nm image sensor was used to achieve double shallow trench isolation etching.Due to the need to control different trench depth in the pixel area and the logic area,the process is complicated.Through a series of technological explorations,and with the help of experimental design scientific analysis tool,the best process conditions were finally found.In the end,the indexes all arrived at the process requirements,and the smallest line spacing of the pattern hadn't double slope phenomenon.The depth loading effect of the SIN loss was optimized to 170?,and the depth loading effect between Iso/Dense was less than 92?.The process window experiment shows that the process pressure and the O2 flow fluctuate in +/-10% and the profile is normal.Applied in mass production stage,mainly involves three problems.Firstly for the problem of leakage current of low power consumption products,a new optimization scheme was proposed to optimize the profile of shallow trench.The top corner curvature of the improved trench rose sharply from 4.9nm to 13.4nm,reduced product leakage,The overall performance improved ~ 30%,and the final technological window was 12+/-3s,which made the leakage parameters of low-power products of NMC platform reached the standard of imported models.Secondly the defect of wafer center was caused by the gas inlet which located at the top of chamber.After optimization,the probability of wafer center's cluster etching block defect was reduced from 1.5‰ to 0.1‰.The MTBC of the machine was also greatly improved,and the second trench increased from 50 hrs to 200 hrs.Thirdly for the edge of the wafer block defect problem,by improving the material of the sealing ring at the bottom of the ESC,the anti-corrosion performance of the plasma was enhanced,and the defect rate decreased from 3% to 0.2%;Meanwhile,the life time of ESC can be increased from 5000 hours to more than 10,000 hours.