Electromigration đã được xác định là một chế độ thất bại chính của đường dây kết nối được sử dụng trong các mạch tích hợp bán dẫn. Nó là một mật độ cao hiện tại do khối lượng vận chuyển hiện tượng biểu hiện chính nó như là khoảng trống, gò, hoặc mở mạch, do một động lực trao đổi giữa các điện tử dẫn và các nguyên tử kim loại máy chủ. | 5 Silver Electromigration Resistance Introduction Electromigration has been identified as a primary failure mode of interconnect lines used in semiconductor-integrated circuits. It is a high-current density induced mass transport phenomenon manifesting itself as voids hillocks or open circuits due to a momentum exchange between conduction electrons and host metal atoms. The electromigration failure of Al Cu interconnects has been extensively investigated because of the dominant use of Al Cu as conductors in microelectronics devices for decades. Recently the electromigration study of Cu has been conducted considerably as well since the trend to replace Al Cu with Cu is becoming apparent for ultra large scale integration ULSI applications. Ag as the most conductive metal has also drawn attention as an interconnect material for some potential applications in ULSI 1 2 . Ag has some advantage over Cu in terms of the conductivity. Since the wide application of Cu metallization will be facing some difficulties 3 Ag may find its applications if the electromigration resistance can be further improved and some other issues 2 can be addressed. Compared to Al Ag is expected to have better electromigration resistance. However the electromigration resistance of Ag needs to be further improved in order to be comparable to Cu. A novel encapsulation process is described for patterned Ag lines and the effect of this process on the Ag electromigration is evaluated. 76 Silver Metallization Experimental Details Ti film 50 nm and Ag film 100 nm were sequentially deposited on a thermally oxidized 100 Si wafer without breaking vacuum in an electron beam evaporator. The base pressure before Ti deposition was approximately 10 7 Torr. The Ti film was mainly used to form an encapsulation layer on the Ag line surface as will be shown later. A conventional optical lithography process was used to transfer the designed mask pattern onto the deposited Ag Ti SiO2 Si films. The pattern .
