To help, knowledge of diamond's anisotropic properties and how reaction parameters determine the crystallographic plane presented for grinding are important. The soft and hard directions on this plane, however, are still randomly oriented. The geometric problems which arise when dealing with CVD diamond material dictate the amount of material that must be removed and, therefore, the time involved. The as-grown side of the wafers is not flat but has an undulating or dome shaped surface. Fifty micron thickness differences across a 50 mm diameter 400 micron thick wafer are common.
Internal stress creates bowed wafers.
DDK has 30 years of experience making ultramicrotomy knives from diamond. The edges of our knives have been shown to have radii of curvature of 20 Angstroms or less, the sharpest edge that has ever been put on any material. Flaws in the facets that form this edge give unacceptable results so great effort is made to achieve facets that are smooth on a atomic scale. DDK is now making this process available on a toll manufacturing basis. To obtain free-standing CVD diamond films, it is necessary to remove the substrate from the film.