the drive shaft is rotated in a preferred forward direction. To aid in the proper assembly of the coupling, markings are provided on the hollow core nest and on the elongate bodies. Also, the nest preferably includes four slots, each slot having a strip that serves as the spring element, and the elongate bodies each include two posts.
In another preferred embodiment, the plurality of spring elements comprise helical coil springs, each having opposed ends that apply the biasing force between a first post on one elongate body and a second post on the other elongate body. In this embodiment, each post includes a hook that engages an end of one of the helical coil springs. The hollow core nest preferably includes a plurality of channels on its outerIn recent years, in the manufacturing of semiconductor devices, the Chemical Mechanical Polishing (CMP) method is in wide use for planarizing insulating films, metal films, polycrystalline silicon films or the like formed to fill in grooves formed on a substrate. The CMP method is a method which supplies a polishing agent (a slurry) containing abrasive grains and a chemical solution onto a polishing cloth and brings a work piece into contact with the polishing cloth, thereby planarizing a work surface by combining the chemical action of the chemical solution and the mechanical action of the abrasive grains. However, in the CMP method, mechanical damage caused by the abrasive grains may not be avoided, and there is a problem in that abrasion damage occurs on the work surface.
In relation