Patent ID: 7661385

Claim:
A device for spin-coating substrates with liquid media, comprising: a rotatable substrate holder, for horizontally supporting a substrate, rotatably arranged in an annular trough unit; a covering unit for covering the substrate during a distribution operation of the liquid media as the substrate holder rotates; and an attachment, provided on the annular trough unit, substantially surrounding the substrate holder; wherein the substrate holder is joined tightly to the covering unit and a plurality of passage holes are arranged circumferentially on a circumferential wall of the substrate holder so that an internal coating space, defined by the covering unit and the substrate holder, is in fluid communication with an environment outside the internal coating space via the passage holes; wherein the internal coating space is further defined by an inclined internal surface of the circumferential wall of the substrate holder; and wherein a shell-like internal wall surface of the attachment is curved in an arc at a predetermined angle so that a distance between the curved internal surface of the attachment and an outer surface of the circumferential wall of the substrate holder, proximate outlets of the passage holes, is in a range of 20-30 mm so as to increase a Venturi effect in the passage holes to provide an increased extraction effect.