Method of and apparatus for measuring and estimating the cleanliness of

Abstract

To evaluate cleanliness of wafer accommodating members used for storing or transporting of silicon, gallium arsenide or like semiconductor wafers, pure water is poured into a vessel-like wafer accommodating member, such as a wafer case body, a top cover, etc., capable of containing liquid therein, and then low frequency vibrations or supersonic wave is applied to the member. Alternatively, inner wafer accommodating members accommodated in the wafer case body, such as a wafer basket, a wafer retainer, etc., are accommodated in a vessel containing poured pure water, and the low frequency vibrations or supersonic wave is applied to the members. Then, the quantity of particles in the water is counted. Particles that have been attached to the wafer case or to inner wafer accommodating members accommodated therein, such as a wafer basket, a wafer retainer, etc., are made readily separable into the water, thus permitting quantitative detection of generation of particles from the inner wafer accommodating members.