Method to enhance polishing performance of abrasive charged structured polymer substrates

Abstract

The intersection of discrete polishing islands staggered in a curvilinear shape with a workpiece maintains a substantially uniform film thickness throughout the polishing operation and also leading to a stable polishing operation due to the substantially invariant pressurization.

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 / 315,210 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” both of which are hereby incorporated herein in their entirety by reference.FIELD OF THE INVENTION[0002]The present invention is directed to a method and apparatus for an abrasive article with a plurality of polishing islands arranged to generate a constant contact area during polishing.BACKGROUND[0003]Polishing with polyamide or other polymer based substrate materials requires maintaining a constant hydrodynamic film for stability during the polishing operation and reducing the required hydrodynamic film is attainable b...

AI Technical Summary

Benefits of technology

[0013]FIG. 6 shows that attaining a preload reduction of twenty times from the original preload would require groove spacing of 30 nm. Manufacturing processes to achieve such feature size are highly complex and costly. It is very critical to create a very large number of grooves to reduce the fluid hydrodynamic film and reduce the required preload to provide enough spacing between the substrate and the polished bar. Grooving helps in two ways. First it establishes a multitude of individual pressure profiles over the bar contributing at its stability and the sum of the load carried by each individual fluid bearing is lower than the load carried by an equivalent fluid bearing with a length equal to the bar length. The side leakage of each fluid bearing contributes at reducing the load carrying capacity of each individual bearing. The lower preload required avoids deforming the polymeric substrate to a point of rounding the polishing article. The drawback of the solution of generating continuous and concentric grooves spaced with 30-100 nm is very difficult and challenging from a manufacturing viewpoint.

[0014]FIG. 7 shows a configuration with an engineering texture 302 applied to the polyamide 301 and grooves 303. The texture 302 causes high stresses at the interface. Thin film diamond like carbon 304 is applied to the polyamide to impart a hard surface. Subsequently a thin film lubricant is applied to enhance the lubrication of the interface. FIG. 8 shows a configuration 350 with abrasives 351 and a thin film lubricant 352 applied to the interface. Note that a thin film of diamond like coating 353 is applied to enhance the adhesion of the lubricant to the surface of the charged polyamide film can be very desirable in dry lubrication applications.

[0015]Another way to reduce the required applied load to cause desirable hydrodynamic spacing between the lapping bar and the diamond charged polyamide is discussed below. The solution includes reducing the film thickness generated by the shearing of the lubricant during the polishing process. Discrete sets of patterned islands are fabricated in the diamond charged substrate travel underneath the lapping bar causing a uniform hydrodynamic film regardless of the bar location on the substrate. A series of discrete islands are staggered and arranged to expose a substantially constant area under the slider bar. A novel island pattern organized to form a uniform film independent of bar location is presented. The uniform hydrodynamic film is maintained by maintaining a substantially uniform average pressure and a substantially uniform pressure center location as the bar moves with respect to the substrate. Discrete islands of the substrate cause substantial pressure side leakage to reduce the hydrodynamic pressure countering the applied preload.

Problems solved by technology

Manufacturing processes to achieve such feature size are highly complex and costly.

The drawback of the solution of generating continuous and concentric grooves spaced with 30-100 nm is very difficult and challenging from a manufacturing viewpoint.

Discrete islands of the substrate cause substantial pressure side leakage to reduce the hydrodynamic pressure countering the applied preload.

Images