化学机械平坦化过程中抛光垫表面结构对抛光液传递效率的作用机制

Chemical mechanical planarization (CMP) is one of the key processes in integrated circuit manufacturing. It is well known that CMP has high cost and, particularly, slurry accounts for near 50% of the total cost of ownership of the CMP module. During polishing, slurry is transported to the wafer surface to provide chemical and mechanical actions. The pad surface structures (groove, micro hole, roughness, etc.) impact the transport efficiency of slurry, but there have been few reports on its working mechanism. In this proposal, the enclosed space between the wafer and pad will be modeled as a chemical reactor of CMP. The mechanism will explored through combined theoretical and experimental approaches. At first, a calculation model of the volume of the CMP reactor will be built based on the pad surface structure parameters, which can be characterized experimentally. Then, a model of determining the mean residence time of the CMP reactor will be built via applying the classic theory of mean residence time of chemical reactors. Wafers will be polished using pads with different surface structures, and the corresponding mean residence time of the CMP reactor will be obtained. Finally, based on the volume and mean residence time of the CMP reactor, the slurry flow rate entering the CMP reactor will be calculated and the model of the slurry transportation efficiency will be built. This model will provide insight into the mechanism of pad surface structure on slurry transport efficiency and thus help optimization of pad surface structures for reduced slurry consumption in CMP.

化学机械平坦化（CMP）是集成电路制造的关键工艺，具有高成本的特点，特别是抛光液的消耗占CMP总成本的近一半。抛光过程中，抛光垫将抛光液传递至晶圆表面以参与化学和机械作用。抛光垫表面结构（沟槽、微孔、粗糙度等）直接影响抛光液的传递效率，但目前其作用机制方面的研究少有报道。本项目拟将晶圆/抛光垫组成的空间模拟为CMP反应器，采用理论与实验相结合的方法对该机制进行深入研究。首先，建立CMP反应器体积计算模型，关联抛光垫表面结构参数，这些参数可通过实验测定获得。其次，应用化学反应器平均停留时间理论于CMP反应器，建立平均停留时间测定模型。在不同的抛光垫表面进行晶圆抛光，获得相应的平均停留时间。最终，基于反应器体积和平均停留时间，计算进入CMP反应器的抛光液流量，建立抛光液的传递效率模型。该模型将揭示抛光垫表面结构参数对抛光液传递效率的作用机制，从而指导抛光垫表面结构优化设计，减少抛光液消耗。

化学机械平坦化（CMP）是集成电路制造的关键工艺。它具有高成本的特点，特别是抛光液的消耗占CMP总成本的近一半。抛光过程中，抛光垫将抛光液传递至晶圆表面以参与化学和机械作用。抛光垫表面结构（沟槽、微孔、粗糙度等）直接影响抛光液的传递效率，但目前其作用机制方面的研究少有报道。本项目将晶圆/抛光垫组成的空间模拟为CMP反应器，采用理论与实验相结合的方法对该机制进行深入研究。首先，建立CMP反应器体积计算模型，关联抛光垫表面结构参数，这些参数可通过实验测定获得。其次，应用化学反应器平均停留时间理论于CMP反应器，建立平均停留时间测定模型。最终，基于反应器体积和平均停留时间，计算进入CMP反应器的抛光液流量，建立抛光液的传递效率模型。此外，在CMP反应器模型和平均停留时间理论的基础上，本项目还研究了工艺参数对CMP反应器中抛光液混合程度的影响。该项目研究成果将有利于CMP工艺优化，减少抛光液消耗，优化抛光液利用。