To smoothly deliver wafers into a cleaning bath from a conveying chuck, and to prevent the wafer-to-wafer interference in the cleaning bath, by a method wherein the opening angle of the first stage V-groove, on the opening side of a wafer retaining groove, is set larger, and the opening angle of the second V-groove on the bottom side is set smaller.
The section shape of the wafer retaining groove 16 of a wafer retainer 12 is formed into two-stage groove. More specifically the wafer retaining groove 16 has the first stage V-groove 18 on the opening side and the second stage V-groove 20 on the bottom side. As the opening angle α of the first stage V-groove 18 is wide, a cleaning liquid can be taken in and out to and from the first stage V-groove 18 in the state, in which the wafer W is retained in the second stage V-groove 20. Accordingly, the pressure of the first stage V-groove 18 does not in the least become a barrier even when it is considered from the view point of cleaning effect. If the edge is rounded on the connection part 24 between the first stage V-groove 18 and the surface of the wafer retaining main body 14 and on the connection part between the first stage V-groove and the second stage V-groove 20, the wafer W can be inserted smoothly.
MARUYAMA FUMIAKI
EBARA YOSHIJI
