Mosel Vitelic Corporation

Aplex, Inc.

Aplex Group

Other

Shu-Hsin Kao

David E Weldon

Tim H Huynh

Shou-sung Chang

William F Lapson

Charles J Regan

Garry K Kwong

Peter Mok

Huey M Tzeng

Linh X Can

Gregory A Appel

Gregory C Lee

Michael Leach

Harry Lee

Greg Simon

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

An improved wafer polishing machine is disclosed. In one embodiment, the wafer polishing machine has a movable polishing surface and a holder that holds an object, such as a semiconductor wafer, against the movable polishing surface. The holder includes a support structure that supports the object in contact with the polishing surface and an annular retaining ring that retains the object in alignment with the support structure. The retaining ring has a plurality of projections projecting inwardly from its inner circumference. The projections are evenly spaced around the inner circumference of the retaining ring. In one embodiment, the projections on the retaining ring define a circle with a diameter no less than the diameter of the object being polished. In an alternative embodiment, the retaining ring has a smooth, circular inner circumference formed from a flexible material which distends to from a continuous arc of contact with the wafer during polishing. Each retaining ring disclosed herein forms multiple points of contact or a continuous arc of contact between the retaining ring and the wafer, thereby reducing wafer buckling during polishing and improving surface uniformity.

Retaining ring for wafer polishing

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.

A polishing tool uses a seal cavity containing a fluid that supports polishing pads against an object being polished. The boundaries of the cavity include a support structure, a portion of a polishing material, and a seal between the support structure and the polishing material. The polishing material moves relative to the support structure and seal. A variety of seal configurations can maintain the fluid within the cavity. In one embodiment the seal mechanism is a labyrinth seal including multiple ridges. In one embodiment, the seal mechanism is a face-sealing seal which includes a jacket with a u-shaped cross section with a compressible element positioned within it. The face-sealing seal is in a groove positioned outside of the cavity. Alternatively, the face-sealing seal forms the outer edge of the cavity. In a further embodiment, the seal is an o-ring seal positioned within a double dove-tailed groove.

Seal for polishing belt center support having a single movable sealed

Polishing method using a hydrostatic fluid bearing support having

Heat is transferred between a linear CMP belt and an adjacent heat transfer source, providing a predetermined lateral temperature distribution across the belt. Temperature sensors generate feedback signals to control the heat transfer sources. Alternatively, process monitoring sensors provide feedback signals. The heat transfer source can include multiple selectively controllable individual heat transfer sources having differing temperatures, which can be above or below ambient temperature. The mechanism of heat transfer can include one or more of convection, conduction, and radiation. The configuration provides substantial flexibility to establish and maintain selective non-uniform temperature distributions across the polishing belt. This in turn permits precise control and stability of the polishing process. Heat transfer sources can include pulleys, slurry dispensers, polishing pad conditioners or conditioner back supports, fluid nozzles, and sealed fluid cavity belt supports.

Temperature regulation in a CMP process

A polishing tool uses a seal cavity containing a fluid that supports polishing pads against an object being polished. In one embodiment, the boundaries of the cavity include a support structure, a portion of a polishing material, and a seal between the support structure and the polishing material. The polishing material moves relative to the support structure and seal. A variety of seal configuration can maintain the fluid within the cavity. One seal includes an o-ring that the force of a spring, a magnet, or air pressure presses against the polishing material. A gas flow from outside the cavity or from an inlet inside the cavity can form a gas pocket in the cavity, adjacent the o-ring, to prevent leakage of the fluid past the o-ring. Another seal is formed by an aerostatic bearing. The fluid pressure in the cavity can be varied temporally to create vibrations in the polishing material to enhance polishing performance or can be varied spatially to change the pressure profile. One embodiment of the invention includes one or more fluid inlet/outlets to the cavity, one or more pressure regulators, and a controller that operates the pressure regulators to control the pressure in the cavity. In polishers with or without a sealed fluid cavity, the support structure can include actuators that control the orientation of the support structure relative to polishing material. Sensors and a feedback control system positions the support structure for polishing.

Polishing tool having a sealed fluid chamber for support of polishing pad

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Redwood City, CA, United States of America

Shu-Hsin Kao