化学机械抛光中背垫对硅片表面接触压强分布及宏观表面形貌的影响

为了获得单晶硅片化学机械抛光过程中背垫对接触压强分布的影响规律，建立了有背垫抛光过程的接触力学模型和边界条件，利用有限元方法进行了有背垫时的接触压强分布的计算与分析，并利用抛光实验对计算结果进行了验证，获得了硅片与抛光垫的接触表面压强分布形态，以及背垫的物理参数对压强分布的影响规律。结果表明，在有背垫时接触压强的分布仍存在不均匀性，而且在硅片外径邻域内接触压强最大，这导致了被加工硅片产生平面度误差与塌边。增加背垫的弹性模量和泊松比，可以改善接触表面压强分布均匀性，使硅片有效区域的平面度形貌变得更好。

The Effect of Carrier films on Contact Pressure Distribution and Macro-surface Profile of Silicon Wafer in Chemical-mechanical Polishing

In order to obtain the effect of carrier film on contact pressure distribution in the chemical- mechanical polishing(CMP) of silicon wafer, a mechanism model and a boundary equation were set up, then the contact pressure distribution was calculated and analyzed by use of finite element method, and the calculated result was verified by polishing experiments. At last the pressure distribution of con?tact surface between silicon wafer and polishing pad and the rule of that the physical parameters of car?rier film had an effect on pressure distribution were obtained, ana the most important relation between the non-uniformity of contact pressure distribution and the flatness error of silicon wafer in CMP was ensured. The result shows that the contact pressure distribution is non-uniform and the pressure in the outside borderline of silicon wafer is maximal, which leads to the flatness errors and collapse of silicon wafer. When Young’s modulus and Poisson’s ratio of carrier films are increased, the uniformity of contact pressure distribution can be improved, and the flatness topography in the available region of wafer surface become much better.