A Study on the Chemomechanical Polishing(CMP) Properties of Marble

• Main Authors: Lin, Chih-Peng, 林志朋
• Other Authors: Chia-Yon Chen
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/85961426723126535872

碩士 === 國立成功大學 === 資源工程學系 === 85 === ABSTRACT Chemomechanical polishing (CMP) for planarization has become one of the most rapidly growing segments of the semiconductor manufacturing market.Application of CMP for the planarization of interlayer dielectric as well as polysilicon and tungsten metal studs was pioneered by IBM and had been used in the fabrication of very large scale integrated circuits since 1985.CMP is carried out by pressing a rotating wafer against a moving polishing pad on which a suitable slurry is dispensed. For oxide polishing, the slurry consists of silica particles dispersed in an aqueous solution. The oxide surface is chemically modified and this modified layer can be removed by mechanical action. The speed of the marble surface reaction to acid is very fast. We can observe the marble surface before and after acid etching and polishing process by means of infrared spectroscope. Under the acid circumstance, the oxalic acid will react with the marble surface and produces fine calcite particles attached on the surface. After a long time of polishing, this reaction will cause etching pores. In mechanical polishing condition, oxalic acid solution has the function of erosion and can remove the scraps. CMP under alkaline condition, sodium silicate solution has the function of gelation, and forms a film on the marble surface which filling the pores and cracks on the marble surface, instead of planarization. α-serum is a kind of Na- Si organic substance co-precipitated from oxalic acid and sodium silicate. This serum is formed in the range of pH from 1.43 to 3.50 and the particle''s size is distributed between 5μm ~100μ m.. It can dissolve in water, but can''t dissolve in alcohol. α- serum will offer a chemical reaction in the polishing of marble under acid condition. By means of mechanical polishing, it can promote the function of planarization, in the mean time, the chemical reaction can also remove the scraps caused by mechanical polishing. For polishing of the white marble, the largest brightness after mechanical polishing is only 82, but the brightness after CMP of α-serum is above 95. It can also shorten the duration of polishing time. In the polishing experiment, the infusion of chemical polishing after the initial period of mechanical polishing will change the abrasion rate and appear the difference between mechanical polishing and chemical polishing. The variation of line regression rate of brightness can explain the quantity of both mechanical and chemical polishing.