Method and apparatus for accelerated wear testing of aggressive diamonds on diamond conditioning discs in cmp

Abstract

The present invention is a method and apparatus for accelerated pulling and fracturing of aggressive diamonds on a CMP diamond conditioner disc wherein aggressive diamonds of known position are pulled or fractured by contacting the diamond conditioner disc to a plate or sheet of a hard material or a plate or sheet containing discrete structures of hard material relative to which the diamond disc is in motion at a determinable and reproducible rate for a determinable and reproducible period of time and the number and position of the pulled or fractured aggressive diamonds are determined following the completion of said contact.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a method and apparatus for accelerated wear testing of aggressive diamonds on diamond conditioner discs in CMP and an apparatus for carrying out the same.DESCRIPTION OF THE PRIOR ART[0002]Diamond conditioner discs have been used in CMP processes to great effect to maintain the roughness of polyurethane polishing pads. These discs have been produced and marketed by several vendors to standards of reliable quality and effectiveness. Generally, diamond conditioner discs are evaluated based on, among other things, the total number of diamonds present on the surface of the disc and the number of diamonds remaining after certain specified periods of use or environmental testing. However, the effectiveness of the diamond conditioner disc actually depends not upon the total number of diamonds present on the surface of the disc but upon the number of active diamonds present.[0003]Active diamonds are the diamonds that actually conta...

AI Technical Summary

Problems solved by technology

Although simple microscopic examination of diamond conditioner disc sectors and estimation based on the geometric patterns of initial diamond placement and surface area have long provided a method to determine an approximate total number of diamonds on the surface of a diamond conditioner disc, to date there has been no simple, reliable, cost effective method to measure the number of active diamonds.

These diamonds are responsible for a significant and disproportionate portion of the cutting of the polyurethane CMP polishing disc and additionally are under the highest degree of stress and suffer the most rapid degradation from use.

The degradation of aggressive diamonds, far more than is true with other active diamonds, is responsible for the decline in performance of the diamond conditioner disc with use.

Although it is certainly possible to simply use a diamond conditioner disc with a CMP polishing pad in CMP conditioning for as long as is necessary to observe wear on the aggressive diamonds and their eventual pulling and fracturing, and from time to time occasionally remove and check the diamond conditioner disc to observe the progress of the pulling and fracturing of aggressive diamonds using the method described in U.S. patent Ser. No. 12 / 359,722, such a test, though useful, would consume an inordinate amount of time and expensive resources.

Unless the CMP polisher were dedicated solely to one type of operation as the diamond conditioner disc was tested, which would be extremely inconvenient for users of CMP polishers, or even were used simply for the purpose of testing the diamond conditioner disc under constant conditions, which in itself would also be a considerable expense, the justification for which would be difficult, there would be a considerable variation in test conditions over time due to operation under different CMP conditions.

It is not realistic for most users to operate a CMP polishing device with its consumption of expensive pads, slurry and operator time, not to mention the fact that the CMP device cannot then be used in efficient CMP production.

To date, no effective method or apparatus have been disclosed for accelerated wear testing of aggressive diamonds on diamond conditioner discs in CMP and manufacturers and users have been limited essentially to very occasional records of actual failure or decline in usefulness of the diamond conditioner disc to observe the wear of the diamond conditioner disc by pulling or fracturing of aggressive diamonds present on the diamond conditioner disc surface.

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