Mosel Vitelic Corporation

Aplex, Inc.

Other

Aplex Group

Tim H Huynh

David E Weldon

Shu-Hsin Kao

Huey M Tzeng

Mike Chao

Chi Guo

A polishing system such as a chemical mechanical belt polisher includes a hydrostatic fluid bearing that supports polishing pads and incorporates one or more of the following novel aspects. One aspect uses compliant surfaces surrounding fluid inlets in an array of inlets to extend areas of elevated support pressure around the inlets. Another aspect modulates or reverses fluid flow in the bearing to reduce deviations in the time averaged support pressure and to induce vibrations in the polishing pads to improve polishing performance. Another aspect provides a hydrostatic bearing with a cavity having a lateral extent greater than that of an object being polished. The depth and bottom contour of cavity can be adjusted to provide nearly uniform support pressure across an area that is surrounded by a retaining ring support. Changing fluid pressure to the retaining ring support adjusts the fluid film thickness of the bearing. Yet another aspect of the invention provides a hydrostatic bearing with spiral or partial cardiod drain grooves. This bearing has a non-uniform support pressure profile but provides a uniform average pressure to a wafer that is rotated relative to the center of the bearing. Another aspect of the invention provides a hydrostatic bearing with constant fluid pressure at inlets but a support pressure profile that is adjustable by changing the relative heights of fluid inlets to alter local fluid film thicknesses in the hydrostatic bearing.

Polishing system including a hydrostatic fluid bearing support

Hydrostatic fluid bearing support with adjustable inlet heights

A polishing system such as a chemical mechanical belt polisher includes a hydrostatic fluid bearing that supports polishing pads and incorporates one or more of the following novel aspects. One aspect uses compliant surfaces surrounding fluid inlets in an array of inlets to extend areas of elevated support pressure around the inlets. Another aspect of the invention provides a hydrostatic bearing with spiral or partial cardiod drain grooves. This bearing has a non-uniform support pressure profile but provides a uniform average pressure to a wafer that is rotated relative to the center of the bearing.

An automated tracking and control system measures the lateral displacement of a moving belt, using non-contact sensing. The displacement signal is provided to an algorithm that adjusts the tilts of the belt pulleys and steers the belt laterally. Non-contact sensors include inductive proximity sensors, which respond to the metal belt but are immune to airborne slurry and other non-metallic debris in a hostile environment typical of wafer polishing. Other non-contact sensors include shielded optical sensors. Dual sensor configurations cancel response to non-lateral displacements. Instrumentation, such as tension sensors, cylinder pressure sensors, load transducers, and limit switches, provides input to the algorithm. Independent tension signals for each belt edge verify proper functioning of, e.g., pad conditioners. User-specified belt displacements, e.g., dither, sawtooth oscillation, step, ramp, and sweep, combine with selective texturing and other variable pad properties to provide a desired polishing rate profile.

Robust belt tracking and control system for hostile environment

Polishing method using a hydrostatic fluid bearing support having

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San Jose, CA, United States of America

Tim H Huynh