Method and apparatus for high-flatness etching of wafer

An apparatus for high-flatness etching of a wafer characterized by comprising an etching tank and an absorbing and rotating device for absorbing and rotating a wafer, said etching tank provided with two disclike plates formed flatly either wholly or except for the central part thereof and coaxially opposed in the vertical direction across a suitable space as laid parallelly or substantially parallelly with each other, an etchant supply part formed at the central part of either of said plates, an etchant outlet formed of the gap between the peripheral edge parts of said plates, and an etchant flow path formed by said space intervening between the opposed surfaces of said plates, and an opening part formed at a suitable position on at least one of said plates except for the central part thereof, said absorbing and rotating device has the wafer absorbing surface of the absorbing part thereof disposed to confront said etchant flow path via said opening part parallelly with said plates.