CMP过程中抛光盘作用外力的影响因素分析.pdf

制造技术/工艺装备
现代制造工程( Modern Manufacturing Engineering)
2011年第5期
CMP过程中抛光盘作用外力的影响因素分析
许佩霞,袁晓林,蒋建忠
(江南大学机械工程学院,无锡214122)
摘要:根据芯片/磨粒/抛光盘三体接触当量梁的弯曲假设,建立了更加准确合理的抛光盘作用在磨粒上的外力的理论
模型,并通过实例对前人的模型和新模型进行对比。最后借用己有分子动力学模拟结果对理论模型进行验证。结果表
明作用在单个磨粒上的外力与磨粒的直径、磨粒的浓度、抛光盘的弹性模量有关,理论计算值与分子动力学模拟结果基
本一致。
关键词:机械化学抛光;磨粒;建模;芯片
中图分类号:T0115.58;0484.4文献标志码:A文章编号:1671-3133(2011)05-0105-05
Factors influencing the applied force on a sinle micro-particle from pad in CMP
XU Pei-xia, YUAN Xiao-lin, JIANG Jian-zhong
(School of Mechanical Engineering, Southern Yangtze University, Wuxi 214122, Jiangsu, China
Abstract: In accordance with hypothesis of the equivalent beam bending for a three body contact among wafer/particles/
more precise and reasonable mathematical model about the applied force on particles from pad is developed. The model compre-
hensively considers the influence of most valuables in chemical mechanical polishing proeess including pad elastic modulus, parti
cle diameter and slurry concentration. Then, through theoretical calculation of an example, the new model and former models are
compared and analyzed. Finally, after the validation of the molecular dynamics simulation of sliding contact between a single mi
cro-particle and a smooth flat surace, it is found that the theoretical value predicted by the model agrees well with the result of
he molecular dynamics simulation under same chemical mechanical polishing conditions
. ey words: Chemical Mechanical Polishing(MP); abrasive particle; modeling; wafer
0引言
芯片在化学机械抛光过程中,磨粒嵌入抛光盘和
AS
芯片后,形成三体接触。抛光盘的材料较软,芯片压
芯片
入后,抛光盘的接触微凸体表面会包住磨粒,工作压
力p由抛光盘的接触微凸体和镶嵌蘑粒共同承担,三
体接触示意图如图1所示。
磨粒
如果假设磨粒为光滑球体,则影响抛光盘作用在
单个磨粒上的外力F,的因素有:抛光盘和芯片的材料
抛光盘
特性参数、抛光盘表面形貌特征参数、磨粒的材料特
性参数、磨粒直径D及磨粒浓度、工作压力p。由于机
图1芯片/粒/抛光盘/的三体接触示意图
械化学抛光( Chemical Mechanical Polishing,CMP)过程
Luo2:和Qin]将抛光盘作用在单个磨粒上的外
中,芯片表面的硬度会受抛光液的氧化剂浓度和PH力F近似认为:
值的直接影响,因此,F,还与抛光液的化学特性参数有
F.=TDPp,1/4……(1)
关。此外,由于磨粒粒度大小为nm量级,对于磨粒较式中:p,为抛光盘和芯片实际接触面积A,上的接触应
小的CMP过程,磨粒与芯片表面分子间的分子力也不力;D为单个磨粒的直径,nm。
可忽视。
Luo等人的模型考虑的影响因素过少,过于简化。
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万方数据