Keyed wafer carrier

Abstract

A structure for a chemical vapor deposition reactor desirably includes a reaction chamber having an interior, a spindle mounted in the reaction chamber, and a wafer carrier releasably mounted onto the spindle for rotation therewith. The spindle desirably has a shaft extending along a vertical rotational axis and a key projecting outwardly from the shaft. The wafer carrier preferably has a body defining oppositely-facing top and bottom surfaces and at least one wafer-holding feature configured so that a wafer can be held therein with a surface of the wafer exposed at the top surface of the body. The wafer carrier desirably further has a recess extending into the body from the bottom surface of the body and a keyway projecting outwardly from a periphery of the recess along a first transverse axis. The shaft preferably is engaged in the recess and the key preferably is engaged into the keyway.

1 . A structure for a chemical vapor deposition reactor, the structure comprising:
 a reaction chamber having an interior; and   a spindle mounted in the reaction chamber, the spindle having:
 a shaft extending along a vertical rotational axis, the shaft having a top end, a tapered portion extending downwardly from the top end, and a main portion below the tapered portion, the tapered portion defining a tapered contact surface extending around the rotational axis and having progressively increasing diameter in the downward direction away from the top end; and 
 a key projecting outwardly from the main portion of the shaft along a first transverse axis transverse to the vertical rotational axis. 
   
     
     
         2 . The structure as claimed in  claim 1 , wherein the spindle has an aperture extending through the shaft along the first transverse axis and the key includes a shank engaged in the aperture. 
     
     
         3 . The structure as claimed in  claim 2 , wherein the spindle further defines a recess extending from the top end of the shaft along the vertical rotational axis, wherein the spindle further includes a fork removably engaged in the recess, the fork having a pair of tines, the shank of the key being engaged between the tines of the fork. 
     
     
         4 . The structure as claimed in  claim 3 , wherein the shank of the key has a central portion located between the two tines of the fork and end portions adjacent the central portion, the central portion having a width that is less than a separation distance between the tines of the fork, each end portion having a width that is greater than the separation distance, such that the key is interlocked between the two tines and retained by the fork against movement relative to the shaft along the first transverse axis. 
     
     
         5 . The structure as claimed in  claim 4 , wherein the central portion of the key includes oppositely-facing substantially planar side surfaces, each side surface disposed adjacent a surface of one of the tines, such that the key is rotationally fixed by the fork against rotation about the first transverse axis. 
     
     
         6 . The structure as claimed in  claim 3 , wherein the key and the fork each consist essentially of a first material, and wherein the shaft consists essentially of a second material different than the first material. 
     
     
         7 . The structure as claimed in  claim 3 , wherein the fork includes a threaded aperture and the threaded aperture is exposed at the top end of the shaft. 
     
     
         8 . The structure as claimed in  claim 2 , wherein the key has a tip portion disposed outside of the shaft, the tip portion having a height in a longitudinal direction parallel to the vertical rotational axis that is greater than a diameter of the aperture. 
     
     
         9 . The structure as claimed in  claim 8 , wherein the tip portion of the key has a rounded upper surface that faces toward the top end of the shaft. 
     
     
         10 . The structure as claimed in  claim 1 , wherein the key is a first key, the spindle further comprising one or more second keys, each second key projecting outwardly from the main portion of the shaft along a respective transverse axis transverse to the vertical rotational axis. 
     
     
         11 . The structure as claimed in  claim 1 , wherein the reaction chamber has a location element at a wall or a base plate of the reaction chamber, the location element having a known relationship with a coordinate system fixed to the reaction chamber, the structure further comprising a homing tool adapted to be removably coupled to the spindle and the location element. 
     
     
         12 . The structure as claimed in  claim 11 , wherein the homing tool has a slot adapted to receive the key therein. 
     
     
         13 . The structure as claimed in  claim 1 , wherein the spindle has reference indicia defined in at least one of the shaft or the key, the indicia being disposed at a predetermined location relative to the key in a circumferential direction around the rotational axis, the structure further comprising a noncontact vision system adapted to detect the rotational location of the reference indicia, the vision system having a known relationship with a coordinate system fixed to the reaction chamber.