After wafer cleaning, how to change the film?
Name compositionEffectSPMH2SO4: H2O2: H2ORemoval of heavy organic matter, but it is difficult to remove organic matter when it is very seriousDHFHF: (H2O2): H2OCorrosion of the surface oxide layer to remove metal contaminationAPM (SC1) NH4OH: H2O2: H2O can remove particles, some organic matter and some metals, this solution will increase the surface roughness of silicon waferHPM (SC2) HCl: (H2O2): H2O is mainly used to remove metal contamination
Quality solutionCleaning method(a) RCA cleaning:RCA pioneered by Werner Kern in the N.J.Princeton RCA laboratory in 1965, and hence the name.RCA cleaning is a typical wet chemical cleaning.RCA cleaning is mainly used for cleaning the surface film, organic particles and metal contamination.1, particle cleaningThe main APM removal of silicon surface particles (also known as SC1) cleaning solution (NH4OH + H2O2 + H2O) to APM in the cleaning. The cleaning solution, due to the effects of H2O2, the silicon surface has a layer of natural oxide film (SiO2), a hydrophilic surface and between silicon particles can soaking cleaning liquid, silicon surface the natural oxide film and a silicon wafer surface by NH4OH corrosion, the particles will fall into the cleaning solution. The corrosion rate and the particle removal amount of silicon surface, for removing particles, corrosion must be a certain amount. In the cleaning solution, because the potential of silicon surface is negative, and most of the particles are repulsive force to prevent the adsorption of particles to the silicon surface.
2, surface metal cleaning(1) HPM (SC22) cleaning (2) DHF cleaningMetal contamination of silicon surface has two kinds of adsorption and desorption mechanism: (1) compared with the negatively charged silicon high metal such as Cu, Ag, Au, from the silicon surface to capture electron on the surface of the silicon direct formation of chemical bonds. Has a high redox potential of the solution to obtain electrons from these metals, resulting in metal the ionized form dissolved in the solution, so that this type of metal removed from the silicon surface. (2) compared with the negatively charged silicon low metal, such as Fe, Ni, Cr, Al, Ca, Na, K can be easily ionized in solution and deposited on the silicon wafer surface natural oxide film or a chemical oxide film on these metals in dilute HF solution with a natural oxide film or a chemical oxide film is easily removed.3, organic cleaningThe removal of organic silicon surface cleaning fluid used is SPM.SPM with high oxidative capacity, metal oxide can be dissolved in solution, and the oxidation of organic compounds to produce CO2 and.SPM cleaning water can remove the surface of silicon wafer heavy organic contamination and some metal, but when organic contamination is heavy will make carbonization of organic matter and difficult to remove by SPM. After cleaning, the silicon surface residual sulfide, the sulfide particles is difficult to use to water wash out.
