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通过磁控溅射沉积TiN/Ag金属化层作为Cu焊盘的保护层, 非晶态的TiN膜作为阻挡层, 阻止Cu原子的向外扩散; 选择能够与Au丝形成固溶体的Ag薄膜作为键合层, 提高超声键合性能. 超声键合性能测试和抗氧化性能测试表明, TiN/Ag金属化层结构作为Cu焊盘保护层, 具有较好的键合能力, 其键合能力和焊点剪切强度在20-180 ℃的温度范围内随着温度的升高而升高, 在180 ℃时获得了100\%的键合能力, 剪切断裂发生在Au球与TiN/Ag键合面. TiN/Ag金属化层较相同厚度的Ag膜具有更强的抗氧化性能, 原因在于非晶态TiN层对Cu原子的扩散起到了很好的阻挡作用.

Copper interconnect has become the only one option for the semiconductor manufacturing under 110 nm. However, there are some problems to be solved in the copper interconnect, especially the bad bondability due to the oxidation of the copper. In this paper, TiN/Ag metallization was fabricated as the protective layer of copper pad by magnetron sputtering. The amorphous TiN film as the barrier layer to prevent copper atoms diffusing from the copper pad to the surface, and the crystalline Ag film as the bonding layer to enhance the bond abilities. The TiN/Ag metallization was characterized by AFM, XPS, XRD and SEM, respectively, and then the ultrasonic bondability of Au wire and antioxidation property of the metallization were measured. The shear test of the Au ball bond was performed by micro-force tester. Ultrasonic bondability test shows that TiN/Ag metallization as the copper chip protective layer has good bonding performance. The bondability and shear strength of the Au ball bond on the metallization increased with the temperature increase from the room temperature to 180 ℃. The TiN/Ag metallization has 100% bondability at 180 ℃, and the shear failure occurred at the interface of Ag film and Au ball bond. High temperate storage test shows that TiN/Ag metallization has better antioxidation property than the Ag film, since the amorphous TiN layer plays an excellent role of diffusion barrier.