Device for spin-coating substrates
A device for spin-coating substrates with liquid media is provided, including a rotatable substrate plate for horizontally supporting a substrate, and a covering unit for covering the substrate during a distribution operation of the liquid medium by means of rotation of the substrate holder. The substrate holder is adapted to be joined tightly to the covering unit, so that passage holes arranged circumferentially on the substrate holder so that an internal coating space, defined by the covering unit and the substrate holder, is in fluid communication with the environment outside the internal space.
1. 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.
2. The device as claimed in claim 1 , wherein sealing means are provided between the covering unit and the substrate holder.
3. The device as claimed in claim 1 , wherein the shell-like internal wall surface of the attachment is spaced a distance from the circumferentially arranged passage holes of the substrate holder so that during the spin-coating operation, the passage holes of the substrate holder execute a movement relative to the shell-like internal wall surface of the attachment.
4. The device as claimed in claim 3 , wherein at least one of the passage holes of the substrate holder and the shell-like internal wall surface of the attachment are configured so that a predefined negative pressure is produced in the passage holes and in the internal coating space during the relative movement of the substrate holder.