Composite polishing pad

Abstract

An abrasive article referred to as composite polishing pad (CPP) includes a plurality of fixed abrasive elements or a plurality of chemical mechanical polishing (CMP) pads attached to a plurality of pressure pads suspended to flexible structures capable to follow the wafer topography. A plurality of stems with dimpled ends act on the pressure pads to generate desired pressure acting on the wafer. The stems are attached to a spring arrangement capable of substantial vertical deflection under a desired load. In one embodiment a plurality of pressure pads suspended to a plurality of stems by revolute joints. The stems are attached to a spring arrangement capable of substantial vertical deflection under a desired load. In another embodiment, a plurality of pressure pads are attached to a plurality of stems suspended to a series of springs capable of substantial vertical deflection under a desired load.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefits of the filing date of U.S. Provisional Patent Application Ser. No. 61 / 315,191 filed Mar. 18, 2010, which is entitled “Composite Polishing Pad”, U.S. Provisional Patent Application Ser. No. 61 / 315,210 filed Mar. 18, 2010, which is entitled “Method to enhance polishing performance of abrasive charged structured polymer substrates” and U.S. Provisional Patent Application Ser. No. 61 / 315,237 filed Mar. 18, 2010, which is entitled “Method to enhance polishing performance of abrasive charged polymer substrates” all of which are hereby incorporated herein in their entirety by reference.FIELD OF THE INVENTION[0002]The present invention is directed to an abrasive article including a plurality of abrasive element independently attached to gimbal structures.BACKGROUND OF THE INVENTION[0003]The invention relates to modifying the rigid substrate of a fixed abrasive article or a chemical mechanical pad used in semic...

AI Technical Summary

Problems solved by technology

It is difficult to achieve both these objective simultaneously because semiconductor wafers are often curved and warped.

These height variations and the wafer topography of the semiconductor wafer can interfere with the uniformity of the polishing process such that some regions of the wafer become over polished while other regions remain under polished.

Typically, hard (i.e., stiff) pads provide good planarization, but are associated with poor with-in wafer non-uniformity (WIWNU) film removal.

Soft (i.e., flexible) pads, on the other hand, provide polishing with good WIWNU, but poor planarization.

Nevertheless, this approach tends to degrade planarization performance when compared to use of a hard pad alone.

In copper processing, however, WIWNU directly impacts over-polishing (i.e., the time between complete removal of copper on any one area versus complete removal from across an entire wafer surface) and, hence, metal loss and, similarly, planarization as expressed by metal loss.

This leads to variability in the metal remaining in the interconnect structures and impacts performance of the integrated circuit.

The proposed approach by Goetz suffers from a lack of ability to follow the topography of the semiconductor wafer to cause uniform cutting pressure during the polishing process.

In addition short range wavelength pressure fluctuations cannot be readily detected.

Images