GLSI多层铜互连阻挡层CMP中铜沟槽剩余厚度的控制

Control of Residual Thickness of Copper Trench in GLSI Multilayer Copper Interconnect Barrier Layer CMP

GLSI铜布线阻挡层化学机械抛光（CMP）中铜沟槽剩余厚度（HCu）关系着集成电路的电性能,是集成电路制造工艺重要评定参数之一。使用不同配比的新型弱碱性抛光液对多层铜布线的阻挡层进行CMP,研究了抛光液中不同体积分数的螯合剂FA/OⅡ、氧化剂H2O2和抑菌剂BIT条件下对HCu的影响。结果表明,随着FA/OⅡ体积分数的增加,铜的去除速率（vCu）逐渐变大,当其体积分数增至3. 5%后,vCu呈略微下降态;加入H2O2可使vCu先迅速地增加,在其体积分数增至1. 5%后vCu开始下降。FA/OⅡ型螯合剂、H2O2在低体积分数时对铜均有强去除作用; BIT对铜的抑制作用较大,其体积分数的增加使得vCu不断减小。三者的协同作用实现了对HCu的有效控制。

The residual copper thickness in the trench（ H（Cu）） of GLSI copper wiring barrier layer after chemical mechanical polishing（ CMP） process is related to the electrical performances of the integrated circuit,and which is one of the most important evaluation parameters of the integrated circuit manufacturing process. A new weakly alkaline slurry with different proportions was used in the CMP process of the multilayer copper wire barrier layer. The effects of different volume fractions of chelating agent FA/O Ⅱ,oxidant H2O2 and bacteriostatic agent BIT on the HCu were investigated. The results show that with the increase of FA/O Ⅱ volume fraction,the removal rate of copper（ vCu） is gradually increased until the FA/O Ⅱ volume fraction reaches to 3. 5%,then vCu decreases slightly. Similarly,vCu increases rapidly with the addition of H2O2 and then decreases after the volume fraction of H2O2 reaches to 1. 5%. Chelating agent FA/O Ⅱ and H2O2 have strong effects on copper removal at a low volume fraction; BIT has a visible inhibitory effect on copper,vCu constantly declines with the increase of BIT volume fraction. The effectively control of HCu is achieved by the synergy of the three components of slurry.