Flexible Fiber Conditioner for Fine Conditioning of Polishing Pad and its Evaluation in Chemical Mechanical Polishing: Verification of SUS-FFC on Soft Urethane Foam Pad and Proposal of PEEK-FFC
Michio Uneda*,, Naoki Takahashi*, Takashi Fujita**, and Yutaro Arai***
*Kanazawa Institute of Technology
3-1 Yatsukaho, Hakusan, Ishikawa 924-0838, Japan
**Kindai University, Higashi-Osaka, Japan
***Showa Industries International Co., Ltd., Hirakata, Japan
Polishing pad conditioning is essential for achieving stable chemical mechanical polishing (CMP). While diamond disk conditioners (DDCs) are often applied, flexible fiber conditioners (FFCs) have been proposed as a new conditioning tool. FFCs are intended for roughening the pad surface appropriately by bundling fine wire fibers. Our previous study demonstrated the fine conditioning characteristics of FFCs for a hard urethane foam pad. In this study, the conditioning characteristics of an FFC are compared with those of a DDC. First, we evaluate the conditioning performance of an FFC using SUS fibers on a soft urethane foam pad. The result indicates that on a soft pad, the SUS-FFC can restore the pad surface asperities more finely, as confirmed via the stabilized number of contact points based on contact image and luminance value distribution analyses. Subsequently, for a metal-contamination-free FFC process intended for semiconductor CMP, we develop an FFC fabricated using polyether ether ketone (PEEK) and verify its performance via the CMP test of a silicon oxide film. It is shown that the hard pad can be conditioned using the developed PEEK-FFC; this implies that a stable removal rate can be realized immediately after pad break-in conditioning.
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