PHOTOMASK BLANK

The invention relates to a photomask blank. The invention provides a manufacturing method of a photomask blank suitable for preparing a photomask. The photomask is used for a photoetching method of nodes below 20nm; the photomask blank comprises a quartz substrate and a chromium-based material film formed on the quartz substrate; the chromium-based material film is a light-shielding film and has a tensile stress or a compressive stress corresponding to a warpage amount of 50 nm or less. The manufacturing method comprises the following steps: sputtering by using a chromium target and inert gas and reaction gas as sputtering gases under the condition that the flow ratio of the reaction gas to the inert gas is 1-2, thus, a chromium-based material film having an optical density per unit film thickness at a wavelength of 193 nm of at least 0.050/nm is formed on a quartz substrate having a size of 152 mm square and a thickness of 6.35 mm. 本发明涉及光掩模坯。本发明提供一种适于制备光掩模的光掩模坯的制造方法，所述光掩膜用于20nm以下结点的光刻法，该光掩模坯包括石英基板和在该石英基板上形成的