The Study On Barrier Cmp Of Copper Interconnect Based On Solubization Effect

With the feature sizes of integrated circuits continue to shrink,as the only key technology to realize global planarization of large-size wafer,the role of chemical mechanical planarization(CMP)becomes increasingly important.By controlling the removal rate selectivity of barrier layer material,the dishing and erosion defects can be effectively corrected.At present,the international mainstream barrier in 65nm node is acidic with BTA copper inhibitors addition to reduce dishing and erosion.However,the low efficiency of acidic slurry,BTA toxicity and cleaning problems are more and more serious.Therefore,it is a great significance to study the alkaline barrier slurry without BTA and high concentration of oxidants.In this paper,firstly,by reading a large amount of literature data,the mechanism of solubilization effect,alkaline slurry polishing route and barrier-related materials removal,the mechanism of each chemical component effect in slurry were studied.Secondly,a large number of single-factor experiments were designed to study the influence of each chemical composition in the slurry on the removal rate of Cu,Ta and SiO2 in the barrier material.In addition,according to result of the single-factor regular experiment to select some chemical composition ratios with excellent removal rate selectivity.And then,dishing and erosion correction experiment were carried out in 65nm copper interconnect line pattern wafer.The result shows that when the proportion of slurry chemical were 20%colloid silica,1.5ml/L FA/O II chelating agent,0.6ml/L type II surfactant,4.5ml/L FA/O J penetrating agent and 1.5ml/L cosolvent and 0.5 ml/L H2O2,the material removal rate selectivity will be the best,as well as a good correction of dishing and erosion.The depth of dishing and erosion was several nanometers after polishing,it's far below the industrial production requirements 20nm.At the same time,compared with the industrial process line,the polishing time of experiment was 75s,the remaining film thickness of wiring layers has reached the target value already,and the efficiency were increased by 20%.Finally,select chemical composition ratio with excellent removal rate selectivity and excellent dishing and erosion correction to carry out removal rate selectivity experiment of five colloid silica from different manufactures.The results indicate that,in the absence of oxidants,the removal rate selectivity of the XL colloid silica slurry satisfies the requirements.When adding 0.5ml/L concentration of H2O2,only the selectivity from Fuso China NK colloid silica slurry can meet the requirements.