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Research On Atmosphere Plasma Based Horizontal Etching Polishing Of Silicon Wafers

Posted on:2021-03-14Degree:MasterType:Thesis
Country:ChinaCandidate:Z D FangFull Text:PDF
GTID:2428330611499295Subject:Mechanical engineering
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With the rapid development of the semiconductor industry,especially integrated circuit manufacturing technology,the size of single crystal silicon wafers is getting larger and larger.At present,12-inch wafers are wildly used in industries.With the increase in wafer size,the challenges faced by traditional processing technology are increasing.With the grinding,lapping,and chemical mechanical polishing processes,the wafer needs to be pressurized.Stress concentration in wafers may cause damage,even cracking.This brings negative effects for wafer processing.Chemical mechanical polishing has a specific material removal rate,which makes the time cost of the polishing process high.A single crystalline silicon ultra-precision processing technology named Atmosphere Plasma Based Horizontal Etching Polishing(APHEP)is developed.Based on AP-HEP,it is expected to realize high-efficiency ultraprecision polishing of large size single crystalline silicon wafers without stress.This thesis summarizes the research on the process and mechanism of AP-HEP process,including the influence of process parameters on material removal rate,changes of surface roughness and morphology during processing,the sub-surface condition and surface composition analysis after polishing,and the polishing mechanism of AP-HEP.Chapter 1 introduces the background and research purpose of the paper and the research status of ultra-precision processing and atmospheric pressure plasma processing at home and abroad.Chapter 2 presents the generation of Inductively Coupled Plasma(ICP)and the experiment equipment required for the AP-HEP process.Besides,the processing principle of AP-HEP is introduced in detail.Chapter 3 discusses the influence of AP-HEP process parameters on the material removal rate.The process parameters include the flow rate of O2,the distance between the torch and the sample,the power of plasma,and the flow rate of CF4.With the relationship between the parameters and the material removal rate,we can optimize the process parameters to obtain a higher material removal rate.Chapter 4 introduces the evolution of the surface roughness and morphology of silicon wafers during the polishing process.In this chapter,we conducted surface morphology observation and surface roughness measurement on the samples with different processing times.The results are analyzed.In Chapter 5,subsurface damage assessment and surface composition analysis are conducted.The subsurface damage of AP-HEP polished samples,chemical mechanical polished samples,and lapped samples were compared.Besides,the composition of the surface deposits after AP-HEP processing was analyzed,which provided key information for further optimization of the processing process to avoid surface deposition.Chapter 6 discusses the polishing mechanism of AP-HEP processing single crystal silicon wafers.To research the polishing mechanism,the surface microstructures were fabricated and etched with different plasma processing conditions.By observing the changes in the size and morphology of the structure,the polishing mechanism of AP-HEP is proposed.
Keywords/Search Tags:polishing, plasma etching, inductively coupled plasma, single crystal silicon
PDF Full Text Request
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