Patent ID: 7839496
Filing Date: 2010-11-23
Classification: G02B

Abstract:
1. A sample holder for confocal microcopy of a chemical mechanical polishing pad (CMP) sample cut or otherwise removed from either a new or used CMP pad that maintains a uniform load and pressure over the part of the sample visible to a confocal microscope by placing the sample behind a transparent window and holding it against the said window, the sample holder comprising: means for retaining an upper part of the transparent window which has an offset adjacent the transparent window having the same or essentially the same refractive index as the sample so that when the sample is held against the transparent window, the edges of the sample are outside an outer edge of the transparent window; means for retaining the lower part of the sample which presses the sample under a known load against the transparent window, which means possesses lateral dimensions the same as or less than the corresponding dimensions of the sample; means for transmitting a force via a spherical member pressed against the means for retaining the lower part of the sample, the force being transmitted through a load cell to measure the load transferred to the sample, via the means for retaining the lower part of the sample via the means for transmitting force via the spherical member, via a means for transferring and then via the load cell from a posterior housing of the sample holder which is forced together with the means for retaining the upper part of the window by a means for generating a force; and means for adjusting the known load.