Polishing pad with controlled abrasion rate
AssigneeMicron Technology, Inc.
InventorMark E. Tuttle
Life of this patent
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Abstract
A polishing pad is provided, having its face shaped to produce controlled nonuniform removal of material from a workpiece. Non-uniformity is produced as a function of distance from the pad's rotational axis (the working radius). The pad face is configured with both raised, contact regions and voided, non-contact regions such that arcuate abrasive contact varies nonuniformly as a function of distance from the pad's rotational axis. Void density at any distance may be produced by several techniques such as varying void size as a function of working radius or varying the number of voids per unit area as a function of working radius. Either technique produces variation in voided area per total unit area for rings of pad surface concentric with the rotational axis having infintesimally small width.
Claims5
A polishing pad rotatable about a central axis, said pad having a circular, planar face perpendicular to said axis, said face to be brought in spinning contact with a workpiece during a polishing operation, said face comprising both raised and voided regions, said raised and voided regions being configured so as to produce a controlled nonuniform rate of material removal from said workpiece, said rate of material removal being a non-linear function of distance from the pad's rotational axis to a working radius.
Dependencies are inferred from the claim text.