Study On Material And Technology Of GLSI Aluminum Gate CMP

With the highly integrated and stereoscopic of giant large scale integrated(GLSI)circuits,the decrease of transistor feature size and the introduction of new material,the requirement of CMOS transistor performance is continuously improved.In the manufacturing of CMOS transistors with 45 nm and the below size,aluminum gate structure has been replaced by traditional polysilicon gate.Aluminum gate technology is the core technology in the development of microelectronic technology,and the aluminum gate chemical mechanical planarization directly affects the electrical properties of CMOS transistors.Aluminum gate CMP technology has become a key technology for the development of semiconductor industry,and is a frontier subject of current research.It is important to study the removal rate of aluminum in aluminum gate CMP.The study of aluminum removal rate can reduce the damage of CMOS devices and improve the stability of devices,and plays an important role in the production efficiency of industrial production.In this thesis,we have done a lot of experiments on several key polishing parameters,according to dynamics,fluid mechanics and pressure model theory,the influence rule and mechanism of the polishing process parameters and the polishing slurry components on the removal rate of aluminum gate CMP was analyzed.Finally,the mathematical model of the removal rate of Al-CMP was established according to the study of the factors.The control of surface defects such as surface scratches,uneven surface corrosion and surface residual particles after polishing is the key problem in the process of aluminum gate CMP.Various defects can seriously affect the performance of aluminum gate devices.Scratches and residual particles can cause short circuit or open circuit of the device,and corrosion can reduce the stability of the circuit.In this thesis,the influence of the aluminum gate CMP process and polishing slurry components on these defects was obtained experimentally,and the surface scratches were studied deeply by combining the preferential adsorption theory,the stagnant layer theory and the Arrhenius theory.By considering the thickness of the oxide layer on the surface of aluminum,the surface scratch defect model was established including mechanical and chemical effects.Then,the defects of uneven surface corrosion are solved based on the preferential adsorption theory.Aiming at the problem of surface defects after polishing,the causes of defects such as surface particle residue,metal ion and metal oxide were analyzed.In view of these defects proposed aluminum gate post-CMP cleaning,the physical adsorption of nonionic surfactant plays an important role in the removal of residual particles,and the removal of metal oxides by chelating agents is obvious.Through a large number of experiments to determine the surfactant and chelating agent varieties and concentrations,prepared special cleaning solution can effectively remove the residual abrasive particles on the surface and the surface defect of metal oxide residue after polishing,obtained very good surface quality.