An aluminum
alloy plate is provided which is suitable for use as members for apparatuses relating to semiconductors. The
alloy plate is satisfactory in plate thickness precision and flatness and can be inhibited from having surface defects. Also provided is a process for producing the plate. An aluminum
alloy comprising given components is melted (melting step), and
hydrogen gas and inclusions are removed therefrom (
dehydrogenation step and
filtration step). This melt is cast into an
ingot (
casting step). According to need, the
ingot is homogenized by a heat treatment (soaking step). This
ingot is hot-rolled to a given thickness (hot-rolling step),
cut (
cutting step), and finished by smoothening the surfaces (smoothening step). According to need, the plate may be subjected to straightening (straightening step) and a heat treatment, e.g., annealing (annealing step). The aluminum alloy plate obtained has a
surface flatness of 0.2 mm or less per m of rolling-direction length and has fluctuations in plate thickness within +-0.5% of a desired plate thickness.