| Summary: | 碩士 === 國防大學理工學院 === 機械工程碩士班 === 97 === All pad conditioners employ diamond grits with dull cutting angles intersected by crystallographic faces(e.g. 125 degrees formed between cubic and octahedral faces). When diamond crystals with blunt angle are pressed against pad, the deformed polymer (e.g. polyurethane) will yield excessively under compression before rupture. The plastic deformation generates heat that may cause glassy transition of pad material. As a result, the asperities formed on pad top contain most shred polymers that are thermally degraded.
To minimize the dragging effect of diamond dressing, polycrystalline diamond (PCD) blades are made with serrated teeth. These blades can be mounted on pad conditioners with different patterns. For example, 26 blades of 2 cm in length can be arranged radically on the periphery of the diamond disk. Moreover, these blades can be slanted to reduce the cutting resistance during the dressing process. The diamond disks made of PCD blades are used to dress CMP pads (IC1000). The characterization of the asperities formed afterward confirmed that shearing, not dragging, is the major mode of cutting. Due to the clean shaving process of pad, the asperities created contain little thermally transformed materials.
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