Apparatus for spraying a liquid on a spinning surface
AssigneeRCA Corporation
InventorGerard Samuels
Life of this patent
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Abstract
A liquid spray apparatus provides predetermined, uniform quantity of liquid (such as photoresist developer) per unit area of surface by a parabolic cam mechanism, arranged to repeatedly reciprocate a nozzle at a predetermined varying linear velocity a plurality of times over a spinning surface, such as a semiconductor device wafer. The mechanism moves the nozzle at a parabolic varying velocity whereby the liquid is deposited at a uniform quantity per unit area. The cam is continuously rotated and engaged with a spring-biased cam follower during the spraying period. The cam follower is engaged and disengaged with the cam by a programable timer defining the spraying period.
Claims5
In a system for automatically spraying liquid on a device surface rotated at a constant rate including means for moving a spray nozzle over said surface whereby the liquid is dispensed in a spray under high pressure over said surface along a reciprocating linear path, characterized by:
- cam means for moving said nozzle a plurality of times over said surface along said reciprocating diametric path at a predetermined velocity of nozzle movement;
- said cam means including spring biased means for keeping a continuously rotating cam in engagement with a cam follower during a first time period;
- and
- means for automatically interrupting said reciprocating action at predetermined intervals to discontinue the movement of said nozzle over said surface;
- and to position the nozzle at a rest position away from said surface;
- said interrupting means including means to disengage said cam follower from said cam, and, subsequently, to re-engage said cam and said cam follower by said spring biased means such that the nozzle is moved rapidly from said rest position towards said surface to repeat said reciprocating movement;
- whereby said surface is sprayed with a predetermined quantity of liquid per unit surface area.
Dependencies are inferred from the claim text.