| Summary: | 碩士 === 國立成功大學 === 電機工程學系碩博士班 === 97 === In this thesis, we focused on the optimization of the soft landing polish step in a Cu chemical mechanical planarization (Cu CMP) process. With the optimized soft landing polish, one can achieve a better uniformity and less Cu residue, dishing, erosion, etc.
Cu CMP has both bulk polishing and soft landing polish steps to flat wafer surface. During the CMP process, bulk polishing step removes the most Cu layer firstly, then using the soft landing polish step to eliminate the Cu residue preciously. However, the soft landing polish would face various materials such as Cu metal layer, barrier, dielectric layer and oxide during etc in the same time, thus should be paid more attention.
In this work, we adopted the Cu CMP machine (Mirra Mesa, Applied Materials) commonly used in an 8” and 12” foundry for study. The optimization study includes (1) the effect polishing pressure on uniformity; (2) the effect of polishing platen leveling on uniformity; (3) the effect depth of polish pad grooves on remove rate and uniformity. After study in a production line for more than one year, we obtained an applicable and better procedure for the soft landing polish. It is worthy to note, the polishing working pressure modify and PAD platen surface leveling control and PAD surface groove depth control the remove rate and uniformity that be improved in the optimized procedure can be executed without change the design of CMP equipment.
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