(论文翻译 页数:25 字数:8685)摘 要：单步循环过滤，用来去除胶体硅基化学机械抛光（CMP）磨料中尺寸过大的微粒。已证实适当的过滤获得了尺寸过大粒子的快速去除，而不改变化学机械抛光磨料中固体粒子浓度的百分比。为模拟化学机械抛光磨料分配系统的粒子减少开发了数字模型。这些模型预测了粒子浓度与流速、过滤器的粒子去除效率及过滤时间的关系。这些模型表明，为使尺寸过大粒子的快速去除，流速是最关键的参数。预先过滤的主要作用是截获部分尺寸过大的粒子，并保护最终过滤不被过早的堵塞，以便提供过滤器最大的使用寿命。
根据有限数据的检验，循环流程模型足以预测粒子浓度形貌图。归根结底，最佳过滤器的选择决定了流速、过滤器的粒子去除效率、过滤方案（单步与多步过滤）和过滤器的使用寿命。

关键词：化学机械抛光；磨料；大粒子去除；过滤技术
1 引言
在微电子领域，化学机械抛光的磨料有明确的颗粒大小分布，通常细磨粒达0.25毫米。少量大于0.5毫米的大尺寸微粒存在于化学机械抛光磨料系统中。大尺寸微粒过多易造成粒子聚结成块，来自湿润表面的干燥磨料在磨料分配系统内部相互作用，并把处理装置的污染物带进来。在化学机械抛光工作已经完成后，这些微粒会导致晶片表面出现一定的缺陷。过滤已被证明能有效消除来自化学机械抛光中的大颗粒，从而减轻晶片表面的微小刮痕。因此，为提高制造集成电路的产量，过滤已纳入基本建设程序管理。
本次研究调查了在用硅为衬底片做化学机械抛光过滤后，去除大磨料微粒的有效的过滤方式。此外，数学模型模拟已发展到当过滤系统在循环方式下运作时，可以模拟微粒在化学机械抛光磨料分配系统中的变化。通过数学模型，过滤的结果从一个侧面反映了曾经被用来评估微粒浓度的大尺寸微粒浓度的变化。

Proper Filtration Removes Oversized Particles from CMP Slurry Systems
Mike H.-S.Tseng
(CUNO Incorporated 400 Research parkway, Meriden CT 06450,USA)
Abstract: Single stage re-circulation filtrations were performed to remove oversized particles from colloidal silica based Chemical-Mechanical Polishing (CMP) slurry. Proper filtration was demonstrated to achieve rapid removal of oversized particles while not altering the percent solids of the CMP slurry. Mathematical models were developed to simulate particle reduction in CMP slurry distribution system. The models predict concentration as a function of the flow rate, the particle removal efficiency of the filter, and filtration time. The models show that flow rate is the most critical parameter in order to achieve rapid removal of oversized particles. The major role of pre-filtration is to capture a portion of the oversized particles and protect the final filtration from premature plugging in order to achieve rapid removal of oversized particles and protect the final filtration from premature plugging in order to deliver maximum filter service life.
Based on examination of the limited data, the re-circulation flow model adequately predicts the particle concentration profile. Ultimately, selection of the optimum filters depends on flow rate, particle removal efficiency of the filter, filtration scheme (single vs. multi-stage filtration), and filter service life.

Keywords: CMP; Slurry; Pemoval of Oversized Partides; Filtration











Introduction
For microelectronics applications, CMP slurries have a well-defined particle size distribution and are often composed of fine abrasive particles up to 0.25 mm. A small population of oversized particles greater than 0.5 mm is typically found in a CMP slurry system. Oversized particles can result from particle agglomeration, drying of slurry from wetted surfaces, interactions within the slurry distribution system, and introduction of contaminants from handling. These oversized particles affect the level of defectivity on the surface of the wafer after CMP has been completed. Filtration has been shown to be effective in removing oversized particles from copper CMP slurries, resulting in a reduction of micro-scratches on the surface of the polished wafer3. Hence, filtration has been incorporated into the CMP process for improve yield management during the manufacturing of integrated circuits.
This study investigates the effectiveness of several filtration modes on the removal of oversized particles from silica based copper CMP slurries and after filtration. In addition, a mathematical model has been developed to simulate particle reduction in a CMP slurry distribution system when the filtration system is being operated under re-circulation mode. The filtration results of the reduction in oversized particle concentration were used to evaluate the particle concentration profile predicted by the mathematical model.