| With the continuous development of microelectronics technology,the requirements of surface cleaning technology for semiconductor silicon wafers are becoming more and more stringent.For the shortcomings of semiconductor silicon wafer material surface cleaning technology,such as high dosage of chemical reagent,large consumption of pure deionized water,and complicated cleaning process,this paper systematically studied the process principle and technical characteristics of electrochemical cleaning silicon wafer.According to the principle of electrochemical oxidation technology and silicon wafer cleaning process characteristics,the paper puts forward a new technology of electrochemical cleaning of silicon wafers,namely using surfactant and chelating agent ethylenediamine tetraacetic acid(EDTA)as a clean process of primary cleaning fluid,again with boron diamond membrane electrode as catalytic anode electrochemical oxidation,and with strong hydrogen peroxide oxidation cleaning fluid to clean depth,the paper’s main research results are as follows:1.Non-ionic surfactant,fatty alcohol polyoxyethylene ether(APE),was used in the primary cleaning agent to study the cleaning technology of surface particle pollution of silicon wafer,such as cleaning temperature,time and cleaning agent flow rate.Study found that APE concentration from 0.1% to 0.5%,cleaning temperature is 70 ℃,10 min cleaning time,cleaning fluid velocity of 200 m/h,ultrasonic frequency on 80 k Hz,the most appropriate cleaning process parameters,such as particle removal efficiency is best,particles of pollutants after cleaning for 5-29 points,and to explore the washing temperature,cleaning time,cleaning fluid velocity of particle removal efficiency of pollutants,there is no significant difference among the orthogonal.2.The cleaning technology of silicon wafer surface metal was studied by using chelating agent EDTA.The results showed that the concentration of 1% EDTA chelating agent,cleaning temperature is 70 ℃,10 min cleaning time,cleaning fluid velocity of 200 m/h,ultrasonic frequency in the cleaning process parameters such as 80 k Hz,sodium ions on the surface of the silicon wafer after cleaning is only 0.12% 0%,0.5% calcium ion,copper ion,magnesium ion 0.1%,these ions has almost completely cleared.3.Based on the electrochemical cleaning principle,a new electrochemical cleaning process was proposed,in which boron-diamond film electrode was used as the electrochemical oxidation catalytic anode and hydrogen peroxide strong oxidation cleaning liquid was used as the cleaning agent.The research results show that after completing primary cleaning to clean the electrochemical,strong oxidation pyrophosphate electrolyte concentration is 0.5mol/L,cleaning temperature is 70 ℃,6 min cleaning time,cleaning fluid velocity of 200m/h,cleaning process parameters,such as the silicon wafer surface after cleaning element C elements(7.6%),control batch RCA cleaning method of the surface of the silicon wafer cleaning element C elements(18.02%),electrochemical cleaning method compared with the RCA cleaning method can effectively remove organic pollutants,the surface roughness is only 1.19 nm,reach the nanoscale.4.Combined with the experimental results,the mechanism of the new silicon wafer surface cleaning technology proposed in this paper is studied.In this paper,it is believed that hydrogen peroxide,after being electrolyzed by boron-doped diamond film,produces hydroxyl radical and O3 with strong oxidability,which can completely remove organic pollution on silicon wafer surface.At the same time,the residual surfactant and chelating agent on the silicon wafer surface are removed together without secondary contamination.By comparing and analyzing the cleaning results of RCA cleaning method,the cleaning process based on electrochemical strong oxidation liquid cleaning method is more effective in removing particles,metals and organic pollutants,which provides a new reference for silicon wafer surface cleaning process. |
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