PURPOSE: To aim at improvement in parallelism and flatness, by applying a first polishing to both sides side by side of the sheet stuck to a work holder via wax, correcting each surface roughness and, after stress release by means of heating and annealing, applying a second polishing likewise.
CONSTITUTION: A workpiece 1 of a germanium sheet or the like is stuck to a work holder 2 via wax 3, while a first polishing by diamond abrasive grains is applied to a polishing surface A, and surface from and surface roughness are corrected. Next, the surface A is turned down, and surface form and surface roughness of a polishing surface B are corrected likewise. Afterward, it is heated up to a temperature, for example, of 60W80°C where the wax 3 is melted, annealed, stress is released, and the workpiece 1 is clamped in a curved state by a polishing strain difference, applying a second polishing to the A surface as well, then it is turned down, thus this second polishing is applied to the B surface as well, and both surfaces A and B are formed into a polished surface being high in from accuracy. Thus, parallelism and flatness is both surfaces of the sheet are polishable so favorably and, what is more, such a surface that is high in form accuracy is securable.
HARA SEIICHI
MATSUNAGA HIROYUKI
