(Department of Inorganic Materials, Central South University, Changsha, Hunan 4 10083)
This project is a major international cooperation project of the Ministry of Science and Technology.
First, the content introduction
(1) Purpose and significance
After the world semiconductor industry enters the era of large-size wafers, it is required that IC components have the best surface flatness to meet the manufacturing process of micron and submicron integrated circuits. Chemical mechanical polishing (CMP) is the best technology in global planarization at present, and it is also the only effective method to solve the global planarization of multilayer insulating dielectric layers and multilayer metal wiring, with simple processing technology and low cost.
There are only a few suppliers of CMPA varnish and micron abrasive in the world, and the demand of domestic semiconductor factories depends on imports. Compared with imported CMPA varnish products, domestic CMPA varnish products are not only fresh, but also reasonable in price, fast in delivery, timely in supporting services and professional in technical support.
(2) Key technologies
Study on phase equilibrium law and particle classification technology of high temperature molten salt in 1. zircon sand -Al2O3 system
The molten salt phase equilibrium of zircon sand -Al2O3 system at high temperature was determined, and the composition of equilibrium species was studied by XRD technology to determine the conditions for forming high performance ZrSiO4-α-Al2O3 abrasive. The technology of superfine grinding and controlled classification is studied, and the technological conditions for obtaining abrasive with uniform particle size distribution, good dispersibility and certain regular edges and corners are determined. A high-value utilization way of natural resources for producing high-value-added electronic device abrasives from natural zircon sand was developed.
2. Preparation and stable dispersion technology of composite nanoparticles.
The research contents include: (1) Through the basic research on the controlled growth of nano-SiO _ 2-Al _ 2O _ 3, SiO _ 2-CEO _ 2 and Al _ 2O _ 3-CEO _ 2, the formation conditions of spherical nano-composite particles and the removal process conditions of Na+ were determined; Study the surface chemical properties and solution chemical properties of nano-composite powder; The variation of particle surface charge in suspension of composite particle system with different ionic strength, pH value and solution properties was studied. The dynamics and electrical properties of polishing solution system, as well as the mechanism and dynamics of polishing solution agglomeration, were studied, and the technological conditions of polishing solution stabilization were determined. Based on the nano-rough polishing and fine polishing theories of SiO _ 2 system, SiO _ 2-Al _ 2O _ 3 system and SiO _ 2-CEO _ 2 system, a multi-purpose CMP polishing solution with international advanced level has been developed.
3. Using molecular simulation technology to study the formula of polishing solution.
Based on computational chemistry, the interaction between components in polishing solution and the surface of silicon wafer is simulated on SGI workstation by using software such as cerius2.0 and gaussian 98, which can guide the design of polishing solution formula.
Second, popularization and application
It is the first time at home and abroad to prepare micron-sized abrasives and stabilize nanoparticles uniformly by using natural zircon sand. The key technologies are the formation of uniform ZrSiO _ 4-α-Al _ 2O _ 3 phase, appropriate crushing and classification technology, preparation of nanoparticles and uniform stabilization technology and technology. In the aspect of high temperature molten salt phase diagram, the phase diagram of multicomponent molten salt system was successfully predicted by neural network technology, and it was applied in KBr- manganese sulfate-cesium chloride system. In the study of fine particle classification technology, ZrSiO4-α-Al2O3 particles with an average particle size of 7.2 1μm and concentrated particle size distribution can be obtained in the laboratory, which shows that zircon sand can be used to prepare high-grade abrasives, but the core technology of this product lies in the control of phase diagram to obtain products with uniform composition. The idea is to obtain the binary phase diagram through experiments, and then simulate the influence and melting type of the main impurities Fe2O3, MgO, CaO and TiO2 in zircon sand by neural network technology, so as to determine the types and composition of the equilibrium solid phase, so as to achieve the purpose of separating impurities and obtaining uniform ZrSiO4-α-Al2O3 products.
Three. Identification, awards and patents
This project has applied for 4 national invention patents, and the related products have been tried in some domestic units, with ideal results and great promotion value in the semiconductor field.