Study On Improvement Of Surface Evenness Of Aluminum Gate Chemical Mechanical Polishing

Surface evenness of aluminum gate in HKMG structure of CMOS manufacturing technique directly affects the electrical performance of CMOS device.The slurry of aluminum gate CMP is acidic on the international.Its slurry usually used phosphoric and nitric acid.It can cause air pollution with hazardous gaseous emissions and can also cause water pollution due to the effluent of waste water which contains phosphates and nitrates.Hence,this paper study on aluminum gate alkaline slurry.Aluminum,as a metalloid and hydrogen-before metal can produce lots of hydrogen bubble on aluminum surface when the value of pH is greater than 8.3 or smaller than 5,which may causes the uncontrollability of surface chemical reaction and a lot of corrosion pit defect.Corrosion inhibitors is needed in slurry.But it is harmful to the equipment.So it is difficult for researching on aluminum gate alkaline slurry without corrosion inhibitors.Aiming at the technology problems of aluminum gate CMP,aluminum gate alkaline slurry in this topic adopt independent research and development FA/O II chelating agent.FA/O II chelating agent is a stronger chelating,easy to wash and eco-friendly.This paper mainly study on behavior characteristic of static corrosion and electrochemical corrosion in alkaline conditions with the function of H₂O₂ and FA/O II chelating agent.Combined with the influence of surface evenness and removal rate in different H₂O₂ and FA/O II chelating agent concentration,aluminum gate CMP electrochemical corrosion mechanism model can be built.This paper is based on arrhenius equation and response transient throry.It mainly study on mechanism of controlling aluminum gate chemical-mechanical planarization.When H₂O₂ is 2.0 vol.%,FA/O II chelating agent is 1.5 vol.%and SiO₂abrasive is 20 wt%,passivation-complexing-mass transporting process reaches the dynamic balance.It is good to solve hydrogen evolution corrosion on aluminum surface and achieve a higher surface evenness and a higher removal rate in aluminum gate CMP process.At the same time,aluminum gate CMP slurry also adopt independent research and development FA/O I nonionic surfactan,and has high permeability and low surface tension.Combined electrochemical workstation with AFM and contact angle measurement,this topic mainly study on the effects of FA/O I nonionic surfactan on surface tension and physical absorption,which solves hydrogen-evolution self-corrosion of aluminum form such aspects as technology,materials,theory.It is useful to obtain a better surface evenness and solve hydrogen evolution corrosion better.This topic study on some mainly process parameters.The best various process parameters can be obtained though dynamics,fluid mechanics and pressure model theory.This paper provide systematic research methodology and credible experimental data.What's more,a new aluminum gate CMP model is came up,which has important guiding meaning on improving the surface evenness of aluminum gate CMP.