CMP过滤技术的进展(英文)

Advances in CMP Filtration Technology

叙述了新一代CMP浆料的过滤工艺和方法。低比重和极小平均粒子尺寸的二氧化硅、氧化铝及氧化铈磨料在这些浆料中要求严格地控制在0.5μm,甚至对平均工作粒影响最小的更小粒子(例如0.03～0.2μm)以内。目前CMP浆料大量生产的加工目标将积累的大于0.56及1.01μm的大颗粒减少了90%,在一次通过或现场使要求如此高的隔离过滤。根据浆料的特性能够采用的过滤方法如分级筛选密度、多薄层法、深褶媒质以及薄膜过滤法。CMP浆料过滤器的有效设计必须考虑到浆料磨损类型和成分、基本化学特性、LPCS、平均粒子尺寸分布、固体比重、粘性、磨料沉积速率、所需的粒子滞留、△P、流速稳定性和期望的过滤器寿命。由于磨料中相同的过滤器媒质性能根据浆料中磨料和添加剂的不同可能有很大的差别,新浆料过滤的最佳参数选顶实质上仍然保持了以实验为根据的方法。根据实验室表示特性、现场性能测试和过滤后的使用评价的数据,可以用作过滤最佳参数选定。由这些测试的典型结果现实,更新的氧化铈和氧化铝以及固有的二氧化硅CMP浆料的过滤有利于大颗粒的控制。

In this paper, we describe filtration methodology and approaches for new generation CMP slurries. Low weight % contents and much smaller mean particle size of silica, alumina and ceria abrasives in these slurries demand tighter retention of ≥ 0.5 μm and even smaller particles with least effect on the mean working particles (e.g. 0.03 - 0.20 μm). Current CMP slurries bulk manufacturing processes target up to 90 % reduction in cumulative large particle counts (LPCs) at ≥ 0.56 or 1.01 μm. Such high retention filtration is needed in a single pass or at the Point-of-Use (POU). Potential filtration approaches e.g. graded density, multiple thin layer, and pleated depth media, and/or membrane filtration may be employed based on slurry characteristics. Efficient designing of CMP slurry filters must consider the slurry abrasive type and composition, background chemicals, LPCs, mean particle size distribution (PSD), wt % solids, viscosity, abrasive settling rate, particle retention needed, .p, flow rate stability, and expected filter lifetime. Since same filter media performance can be very different based on the abrasive and additives in the slurry, filter optimization of new slurries still remains empirical in nature. Data from laboratory characterization, field performance tests, and post-use filter evaluations can be used for filter optimization. Typical results from these tests show that filtration of newer ceria and alumina, and historic silica CMP slurries is beneficial in managing large particles.