Study On Cmpand Electrochemical Characteristics Of Glsi Multilayer Copper Wiring Co Barrier Layer

Integrated circuit(IC)process technology is an important foundation for the continuous development of integrated circuits in China.Chemical mechanical planarization(CMP)is one of the key processes for IC manufacturing.It is currently the only technology that can achieve global and local planarization.Below the 14nm technology node,Co has good diffusion barrier and adhesion to Cu,and is one of the new competitive barrier materials.As device feature sizes continue to shrink and the thickness of the barrier layer continues to decrease,during the CMP process of the barrier layer in the IC process,Cu/Co removal rates and removal rate selectivity are difficult to control,and galvanic corrosion is serious.Affects the yield of polishing pads and restricts the development of integrated circuits.This paper will be from the polishing mechanism,electro-couple corrosion,surface appearance and other aspects of in-depth study,to explore the law of material removal rate and mechanism.Therefore,this topic is carried out as follows:For acid polishing liquid,there are problems such as corrosion of equipment and corrosion of metal Co.pH has a great effect on the static corrosion rate of Co.When the pH of the polishing solution is 10,the static corrosion rate of Co is 9(?)/min,and the damage of the low-k dielectric layer by the strong alkaline solution is effectively reduced.Aiming at the problem that the high abrasive concentration will cause the surface of the material to be scratched,the abrasive concentration was selected to be 5wt%for subsequent experimental research.For the removal rate selectivity of Cu/Co.The influence of each component of the polishing liquid on the selectivity of Cu/Co removal rate was studied by fixing the polishing liquid at pH 10 and the abrasive concentration at 5wt%.The results show that when the FA/OII concentration is 1wt%and the H₂O₂concentration is 1.5ml/L,the Cu/Co removal rate reaches 220(?)/min and 602(?)/min,respectively;the Cu:Co removal rate ratio is close to 1:2.75,achieving The higher removal rate selectivity.For Cu/Co,there is a serious problem of galvanic corrosion.The effects of the new inhibitor TT-LYK on the corrosion of Cu/Co galvanic couples were studied using dynamic and static electrochemical methods.The results show that pH=10,FA/OII concentration is1wt%,H₂O₂concentration is 1.5ml/L,and adding 1ml/L of TT-LYK can effectively reduce the corrosion potential of copper and reduce the Cu/Co potential difference to 4m V.In order to solve the problem of poor surface quality of Cu/Co using the above-mentioned polishing solution,adding a non-ionic surfactant to the polishing solution improves the surface quality of Cu/Co,and at the same time has a small effect on the selectivity of Cu/Co removal.The results show:pH=10.The abrasive concentration is5wt%,FA/OII concentration is 1wt%,H₂O₂concentration is 1.5ml/L,and the concentration of BRIJ30 is 10ml/L.The removal rate ratio of Co is 1:2.75 and the surface quality is good.