Hwang Sohee, Park Jihee, Kim Woonjung
Department of Chemistry, University of Hannam, Daejeon 34430, Republic of Korea.
Polymers (Basel). 2024 Dec 22;16(24):3593. doi: 10.3390/polym16243593.
The chemical mechanical polishing/planarization (CMP) is essential for achieving the desired surface quality and planarity required for subsequent layers and processing steps. However, the aggregation of slurry particles caused by abrasive materials can lead to scratches, defects, increased surface roughness, degradation the quality and durability of the finished surface after milling processes during the CMP process. In this study, ceria slurry was prepared using polymer dispersant with zinc salt of ethylene acrylic acid (EAA) copolymer at different contents of 5, 6, and 7 wt% (denoted as D5, D6, and D7) to minimize particle aggregation commonly observed in CMP slurries. Among them, the D7 sample exhibited smaller particle sizes compared to commercial ceria slurry, which was attributed to the influence of the carboxyl groups (-COOH) of the polyacrylic acid polymer coating the ceria particles. It is believed that the polymer dispersant more effectively adsorbs onto the particle surfaces, increasing electrostatic repulsion between particles and thereby reducing particle size. Furthermore, the stability of the prepared slurry was evaluated under extreme conditions over three months at 25 °C (both open and closed conditions), 4 °C, and 60 °C. The D7 slurry remained stable with no significant changes observed. In addition, the prepared D7 ceria slurry exhibited a slightly higher removal rate (RR) and better uniformity, which can be attributed to the smaller particle sizes of the ceria nanoparticles compared to those in the commercial slurry. This suggests that the colloidal stability of the D7 ceria slurry is superior to that of the commercial ceria slurry.
化学机械抛光/平面化（CMP）对于实现后续层和加工步骤所需的理想表面质量和平面度至关重要。然而，在CMP过程中，研磨材料导致的浆料颗粒聚集会导致划痕、缺陷、表面粗糙度增加，降低研磨过程后成品表面的质量和耐久性。在本研究中，使用含有不同含量（5 wt%、6 wt%和7 wt%，分别表示为D5、D6和D7）的乙烯丙烯酸（EAA）共聚物锌盐的聚合物分散剂制备了氧化铈浆料，以尽量减少CMP浆料中常见的颗粒聚集。其中，与商业氧化铈浆料相比，D7样品的粒径更小，这归因于包覆氧化铈颗粒的聚丙烯酸聚合物的羧基（-COOH）的影响。据信，聚合物分散剂更有效地吸附在颗粒表面，增加颗粒之间的静电排斥力，从而减小粒径。此外，在25℃（开放和封闭条件）、4℃和60℃的极端条件下对制备的浆料进行了三个月的稳定性评估。D7浆料保持稳定，未观察到明显变化。此外，制备的D7氧化铈浆料表现出略高的去除率（RR）和更好的均匀性，这可归因于与商业浆料相比，氧化铈纳米颗粒的粒径更小。这表明D7氧化铈浆料的胶体稳定性优于商业氧化铈浆料。
