Parallel multi wafer axial spin clean processing using spin cassette inside movable process chamber

Abstract

A system and method concurrently processes multiple wafers. A cassette structure includes multiple chucks and a drive spool for supporting and rotating the chucks. Each chuck holds a wafer in position while rotating. The cassette structure is loaded into a process chamber. Each chuck includes a self-locking mechanism that is activated by the centrifugal force generated from the rotation of the chuck. The self-locking mechanism centers and holds a wafer in position with respect to the chuck. A drive motor drives the drive spool, which causes the chucks to rotate. As the chucks are being rotated, a dispensing assembly delivers a processing chemical to the wafers.

1 . A system for concurrently processing multiple wafers, the system comprising:
 a cassette structure comprising multiple chucks and a drive spool for supporting and rotating the chucks, each chuck configured to hold a wafer in position while rotating; and   a chamber for loading the cassette structure.   
     
     
         2 . The system of  claim 1 , wherein the multiple chucks in the cassette structure are supported in parallel by the drive spool, such that multiple wafers are processed in parallel. 
     
     
         3 . The system of  claim 1 , wherein each chuck comprises at least one pin assembly configured to lock a wafer in position using a centrifugal force generated when the chucks in the cassette structure are rotated. 
     
     
         4 . The system of  claim 3 , wherein each chuck further comprises:
 an upper portion comprising a plurality of circular holes substantially normal to the upper portion, each circular hole located at a radial distance from the center of rotation of the chuck; and   a lower portion comprising at least one cavity that overlaps at least one circular hole of the upper portion,   wherein each pin assembly comprises a pin that extends above one circular hole of the upper portion and an eccentric weight pivotally held in the cavity of the lower portion and configured to turn about the one circular hole.   
     
     
         5 . The system of  claim 4 , wherein when the eccentric weight turns within the cavity about the center of the one circular hole of the upper portion, the pin moves in a circular path about the center of the one circular hole of the upper portion. 
     
     
         6 . The system of  claim 1 , further comprising:
 a motor coupling interface configured to couple the drive spool to a motor.   
     
     
         7 . The system of  claim 1 , further comprising:
 a dispensing assembly configured to concurrently deliver chemicals to the wafers.   
     
     
         8 . A method for processing multiple wafers, the method comprising:
 loading a plurality of wafers onto a plurality of chucks, each wafer placed on one of a plurality of chucks at least partially supported by a drive spool;   loading the cassette structure into a chamber;   rotating the drive spool to simultaneously rotate the plurality of chucks; and   holding each of the plurality of wafers in position for processing using the rotation of the plurality of chucks.   
     
     
         9 . The method of  claim 8 , wherein the plurality of chucks are at least partially supported in parallel by the drive spool. 
     
     
         10 . The method of  claim 8 , wherein holding each of the plurality of wafers to be held in position for processing comprises:
 locking a wafer in position using a centrifugal force generated by the rotation of the plurality of chucks.   
     
     
         11 . The method of  claim 10 , wherein locking the wafer in position using the centrifugal force generated by the rotation of the plurality of chucks comprises:
 providing a number of pin assemblies that are rotatably attached at a radial distance about the center of rotation of the chuck, each pin assembly comprising a pin extending above a circular hole of the upper portion and an eccentric weight pivotally held in a cavity of the lower portion, wherein the eccentric weight turns about the circular hole.   
     
     
         12 . The method of  claim 11 , wherein the centrifugal force generated by the rotation of the plurality of chucks causes the eccentric weight to turn about the circular hole, and wherein turning the eccentric weight causes the pin to move in a circular path about the center of the circular hole. 
     
     
         13 . The method of  claim 8 , wherein the drive spool is rotated by a motor. 
     
     
         14 . The method of  claim 8 , further comprising simultaneously dispensing chemicals to each of the plurality of wafers as the plurality of chucks are rotated. 
     
     
         15 . An apparatus for processing multiple wafers, the apparatus comprising:
 a cassette structure comprising a plurality of chucks and a drive spool for supporting and rotating the chucks, each chuck comprising a self-locking mechanism to hold a wafer in position while rotating; and   a cylindrical chamber into which the cassette structure is loaded.   
     
     
         16 . The apparatus of  claim 15 , wherein the chucks in the cassette structure are at least partially supported in parallel by the drive spool, such that multiple wafers are processed in parallel. 
     
     
         17 . The apparatus of  claim 15 , wherein the self-locking mechanism in each chuck comprises a number of pin assemblies positioned about the center of rotation of the chuck and configured to lock a wafer in position using a centrifugal force generated when the chucks in the cassette structure are rotated. 
     
     
         18 . The apparatus of  claim 17 , wherein each chuck comprises:
 an upper portion comprising a plurality of circular holes substantially normal to the upper portion, each circular hole located at a radial distance from the center of rotation of the chuck, the pin assemblies pivotally disposed at the circular holes; and   a lower portion comprising a cavity that overlaps at least one circular hole of the upper portion when the upper portion is mounted onto the lower portion, and   wherein each pin assembly in the self-locking mechanism comprises a mechanical bearing disposed in one circular hole of the upper portion, a pin that extends above the mechanical bearing, and an eccentric weight pivotally attached to a bottom portion of the mechanical bearing in the cavity of the lower portion and configured to turn about the mechanical bearing.   
     
     
         19 . The apparatus of  claim 18 , wherein the eccentric weight turns within the cavity about the center of rotation of the mechanical bearing and causes the pin to move in a circular pattern about the center of rotation of the mechanical bearing. 
     
     
         20 . The apparatus of  claim 15 , further comprising:
 a dispensing assembly configured to concurrently deliver chemicals to the wafers; and   a plurality of drain ducts along the side wall of the cylindrical chamber to prevent backsplash of the chemicals to lower chucks in the cylindrical chamber.   
     
     
         21 . An apparatus for securing a wafer, the apparatus comprising:
 a circular plate comprising a substantially planar top surface on which the wafer is placed, wherein a radius of the top surface is greater than a radius of the wafer; and   a self-locking mechanism configured to center the wafer about an axis of rotation of the upper circular portion and hold the wafer according to a centrifugal force generated by a rotation of the circular plate.   
     
     
         22 . The apparatus of  claim 21 , wherein the self-locking mechanism comprises a plurality of pin assemblies located, each pin assembly comprising a pin that extends above the circular plate and located at a radial distance from the axis of rotation of the circular plate. 
     
     
         23 . The apparatus of  claim 22 , wherein each pin assembly further comprises:
 a mechanical bearing disposed in the circular plate and configured to serve as a pivot for the pin assembly, the pin extending upward from the mechanical bearing at a radial distance from the center of the mechanical bearing; and   an eccentric weight pivotally attached to a bottom portion of the mechanical bearing and configured to turn about the axis of rotation of the mechanical bearing.   
     
     
         24 . The apparatus of  claim 23 , wherein the centrifugal force generated by the rotation of the circular plate causes the eccentric weight to turn about the axis of rotation of the mechanical bearing. 
     
     
         25 . The apparatus of  claim 24 , wherein the pin assembly is configured to move the pin in a circular path about the axis of rotation of the mechanical bearing when the eccentric weight turns.