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Study On Optimization Of Component Of Rough Polishing Slurry In Multilayer Copper Interconnection CMP For GLSI

Posted on:2018-08-24Degree:MasterType:Thesis
Country:ChinaCandidate:Y D ZhaoFull Text:PDF
GTID:2428330596457833Subject:Microelectronics and Solid State Electronics
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Integrated circuit?IC?has been developed for more than 60 years according to Moore's Law,the transistors per chip have reached 1011,the latest technology node has reached the 7 nm.Therefore IC manufacturing technology is facing great challenges.In the IC BEOL manufacturing,chemical mechanical planarization?CMP?has been recognized as the only effective way to provide the global planarization for the wafer.As the key material of CMP,the slurry directly affects the development level.The stability of alkaline rough polishing slurry for copper wiring is a prerequisite for solving other technical problems.The concept of low abrasive concentration,low alkaline pH value,low pressure,high polishing rate raised by international community has become a trend.In terms of the planarization performance of the slurry such as within-wafer nonuniformity?WIWNU?,dishing,defects,etc.,it is raised more stringent manufacturing requirements.In view of the above problems,this paper focus on the following points:In this paper,firstly the stability of abrasive silica sol?SiO2?and oxidant H2O2 in alkaline slurry was studied.From the DLVO theory and chemical reaction kinetics,the stability mechanism of the above two materials was studied.By changing the process configuration,pH,the proportion of components,the stability conditions of SiO2 and H2O2were discovered.Finally the slurry stability time?after adding to H2O2?was as long as 8days,which met the actual industrial requirements.This thesis has established controlling process of CMP kinetics.With the help of chelator properties of FA/O?chelating agent,the problem of the polishing rate ratio between concave and convex copper has been solved.And the convex copper was rapidly removed,the oxide film was passivated by oxidizing agent in the dishing area.At the same time,the supporting role of corrosion inhibitor benzotriazole further optimized the dishing.Thus,it reduced side effects,which the loss of polishing rate and the difficulty of cleaning,on account of totally depending on the corrosion inhibitor.The feasibility of achieving high polishing rate in the condition of low abrasive concentration and low pressure was analyzed.By theoretical analysis and experimental verification,the slurry exhibits the high CMP efficiency in copper rough polishing.The experimental data are listed:The abrasive concentration was successfully reduced to 0.5 wt%.The concentration of Glycine,FA/O?chelating agent,surfactant,oxidizing agent?H2O2?and benzotriazole were identified as 1.0wt%,2vol%,5vol%,2.5vol%,500ppm,respectively.The polishing slurry was alkaline with pH 10.5.The process parameters were set up as:pressure,1.5psi;speed of polish head/polish plate,87/93rpm;slurry flow rate,300ml/min.The slurry was tested on 12 inch blanket wafer.The copper removal rate is up to 7066?/min;the WIWNU was only 3.01%;the Sq was only 0.450nm.For test of pattern wafer?M1?,the dishing value was reduced to the level of 500??the initial value of 3700??.
Keywords/Search Tags:chemical mechanical polishing, Alkaline copper slurry, stability, WIWNU, dishing, polishing rate
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