Study On The Copper Slurry And Stability Of 14nm Multilayer Copper Wiring

New devices,new materials and new processes are driving the rapid development of integrated circuits in accordance with Moore's law.At the same time,the ultra-precision processing technology of multilayer copper wiring of Giga Scale Integrated Circuit(GLSI)also meets more challenges.Chemical mechanical polishing(CMP)is one of the most effective methods to achieve local and global planarization of wafer surface.Slurry is the most important consumable in CMP process,and its performance directly determines the processing efficiency and quality of the whole wafer.Since the integrated circuit enters the technology node of 14 nm and below,for copper film it has been changed from the traditional two-step polishing to one-step polishing,and the purpose is to achieve higher removal rate of copper and almost zero removal rate of barrier material cobalt.In view of the above problems,the basic research on alkaline slurries with independent intellectual property rights has been carried out.The research results have important guiding significance for realizing the localization of copper film slurries.The specific results are as follows:1.Aiming at the problems of corrosion equipment and difficult cleaning of BTA organic residues in acid slurries commonly used in the world market,the effects of organic amine-FA/OII polyhydroxy polyamine chelating agent with strong chemical effect on CMP of copper film were systematically studied under alkaline conditions.The removal rate reaches 5304?/min,which meets the requirement of rapid removal of copper film(>5000?/min).To solve the problem of strong corrosiveness of organic amine system,the "penetration encapsulation theory" of surfactant was proposed.By adding ADS surfactant with strong penetration,the high removal rate(5062?/min)and low static corrosion rate(442?/min)of copper film in FA/O-ADS system were realized.2.Aiming at the stability problem of FA/O-ADS slurry,the effects of different surfactants on the stability of silica sol abrasives and the copper removal rate were studied based on the double-layer stability theory of sol and DLVO theory.After adding 0.3vol% JFCE into the above slurry,the stability of the polishing solution can be improved to three days while maintaining the copper removal rate,which can meet the requirement of industrial applications.3.In order to solve the problems of high cobalt removal rate and low ratio of copper to cobalt removal rate using the slurry mentioned above,the p H value of slurry was set at 10.5,and the cobalt removal rate tended to zero.In order to solve the problem of poor stability of FA/O system slurry at p H 10.5,glycine was added to the system as a complexing agent,"one-step polishing" of copper film,high removal rate ratio of copper and cobalt(131:1),and stable polishing performance were achieve.