Silicon dioxide-based CMP (Chemical Mechanical Polishing) solution and preparation method thereof

Abstract

The invention provides silicon dioxide-based CMP (Chemical Mechanical Polishing) solution which is applied to global planarization of a very large scale integrated circuit silicon substrate and an interlayer medium and a preparation method of the silicon dioxide-based CMP solution. The polishing solution contains the following components in percentage by weight: 10-50 percent of nano silicon dioxide grinding material, 0.1-10 percent of dispersant, 0.1-10 percent of wetting agent, 0.1-10 percent of chelating agent, 0.01-1 percent of pH (Potential of Hydrogen) regulator and the balance of de-ionized water. The polishing solution is prepared through the means of: modifying with a surfactant, strongly and mechanically stirring, performing high-shear grinding, performing ultrasonic dispersion and the like, and the problem of extreme easiness in flocculation and agglomeration of nano-scale grinding material particles is solved. Since the particle size distribution of the grinding material is narrow, the range is selectable, the polishing rate is easy to adjust and control and the polishing solution is alkaline, equipment is not corroded, less damage is caused, cleaning is easy and the environment is not polluted. The silicon dioxide-based CMP solution can be used for chemical mechanical polishing of the very large scale integrated circuit silicon substrate, the interlayer medium, a shallow trench isolation isolator, conductor and damascene metal.

Description

technical field [0001] The invention relates to a CMP (chemical mechanical polishing) polishing liquid, in particular to a silicon dioxide-based CMP polishing liquid applied to the global planarization of silicon substrates and interlayer dielectrics in ultra-large scale integrated circuits and a preparation method thereof. Background technique [0002] With the reduction of the feature size of VLSI devices and the improvement of integration, it is required that the average roughness Ra and average waviness Wa of the surface of the silicon substrate or interlayer medium should be less than 1nm. For this reason, the CMP polishing solution must be made to high speed, low damage, high selectivity and easy cleaning. In order to improve product competitiveness, while meeting these requirements, we must also do everything possible to reduce production costs, reduce energy consumption and environmental pollution. But for the manufacture process of silica-based CMP polishing li...

AI Technical Summary

Problems solved by technology

Large particle nano-SiO disclosed in Chinese patent CN 1155514A 2 Although the manufacturing method of silica sol is also carried out under normal pressure, the particle size dispersion is relatively large, and the reaction time is as long as 24 hours. Finally, particles smaller than 20nm must be filtered out with a microporous membrane, and the final product contains various metal impurities. ion