In 3-dimensional memories such as NAND flash and cross-point memory, the integration fabrication processes face a notable initial-step-height of an isolated SiO 2 -film deposition, which is an extremely critical process removing such initial-step-height perfectly via chemical mechanical planarization (CMP). The SiO 2 -film polishing-rate difference was generated between upper and lower locations of initial-step-height and was evidently depended on the nano-ceria abrasive size in an isolated SiO 2 -film CMP slurry; that is, the polishing ratio of the upper location to lower location remarkably increased from 4.5:1 to 11.5:1, as the ceria abrasive size increased from 21.3 to 81.0 nm. The difference of polishing rate was associated with a local pressure difference between upper and lower locations of initial-step-height; that is, the local pressure at the upper location remarkably increased from 5.2 to 14.2 PSI, while it at the lower location very slightly decreased from 1.0 to 1.3 PSI, as the ceria abrasive size increase from 21.3 to 81.0 nm. Thus, a larger ceria abrasive size in an isolated SiO 2 -film CMP slurry led to better removal ability (i.e., a shorter polishing time of initial-step-height and a thicker remaining isolated SiO 2 -film thickness).

中文翻译：

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湿氧化铈磨料尺寸对隔离 SiO2 膜化学机械平坦化初始台阶高度去除效率的影响

在 NAND 闪存和交叉点存储器等 3 维存储器中，集成制造工艺面临着显着的隔离 SiO 2 薄膜沉积的初始台阶高度，这是一个极其关键的工艺，可以完美地去除这种初始台阶高度通过化学机械平坦化 (CMP)。SiO 2 膜抛光速率差异产生于初始台阶高度的上下位置，并且明显取决于隔离的SiO 2 膜CMP浆料中的纳米氧化铈磨料尺寸；也就是说，随着氧化铈磨粒尺寸从21.3增加到81.0 nm，上位与下位的抛光比从4.5:1显着增加到11.5:1。抛光速率的差异与初始台阶高度上下位置之间的局部压力差有关；那是，上部位置的局部压力从 5.2 PSI 显着增加到 14.2 PSI，而下部位置的局部压力从 1.0 PSI 略微下降到 1.3 PSI，因为氧化铈磨料尺寸从 21.3 增加到 81.0 nm。因此，隔离的SiO 2 膜CMP 浆料中较大的二氧化铈磨料尺寸导致更好的去除能力（即，初始台阶高度的抛光时间更短并且剩余的隔离的SiO 2 膜厚度更厚）。