Intelligent integrated circuit wafer handling system with fail safe system

Abstract

A system for handling stiff but flexible discs, particularly semiconductor wafers, includes a fail safe mechanism that prevents the disc from being dropped if power to the unit is interrupted. A wafer grasping assembly member includes and one or more fingers or posts oriented, or which may be oriented, to a position perpendicular to the plane of the stiff hand assembly member. An electric powered drive system controls the lateral movement of at least one finger or post to cause the wafer to be grasped with controlled traction force between the fixed and moveable posts or fingers. The traction force is controlled by the amount of electrical current fed to the translator solenoid. If the power to the electric powered drive system is interrupted, springs in the system cause the disk to be held between the fixed posts and moveable post or finger until power is restored.

I claim:  
     
         1 . An improved system for handling wafers  
       comprising, in combination: 
 a hand assembly,  
 forward and rearward extensions for grasping, transporting and releasing said wafer to be handled, the forward and rearward extensions being perpendicular to the plane of the hand assembly,  
 control means for programming and implementing a desired sequence of operations;  
 a grasping pressure applied to the wafer by the forward and rearward extensions being controlled by an electrically activated means operatively connected to at least one rearward extension, the grasping pressure being controlled by setting, at a predetermine level, the current fed to the electrically activated means  
 wherein the improvement comprises the addition of biasing means which operate to apply a grasping pressure to the wafer if delivery of controlling electrical current to the electrically activated means is interrupted.  
 
     
     
         2 . An improved system for handling wafers and like 
 substrate means comprising, in combination: 
 a hand assembly,  
 a means for grasping, transporting and releasing said substrate means to be handled,  
 at least a control means for implementing a desired sequence of operations,  
 and grasping pressure control means dependent solely on electrical current fed to a translational means operatively attached to the means for grasping, said means for grasping comprising at least a forward finger and a rearward barrier mounted to the hand assembly, the forward and rearward barrier being orientated perpendicular to the plane of the hand assembly, the rearward barrier being moveable translationally along the plane of the hand assembly to reduce the distance therebetween,  
 wherein the improvement comprises the addition of biasing means which operate to apply a grasping pressure to the wafer if delivery of the electrical current to the grasping pressure control means is interrupted.  
   
     
     
         3 . A device for grasping flat, thin, disc-like media by applying pressure to at least three spaced apart points along the edge of the perimeter of said media, said device comprising: 
 a) a hand assembly defining a plane, said hand assembly having a forward portion, a rear portion, and an upper and lower surface,    b) a barrier means attached to and extending above and perpendicular to the upper surface of the rear portion of said hand assembly and at least one extension attached to and extending above and perpendicular to the upper surface of the forward portion of the hand assembly, the at least one extension and barrier comprising at least one post on the rear portion and at least one finger on the forward portion,    c) the barrier means being a laterally moveable extension, said laterally moveable extension moveable generally in the direction of the at least one extension to cause the at least one extension and the barrier means to contact the perimeter of a flat, thin, disc-like media placed there between, said movement of the laterally moveable extension being caused by the application of an electrical current to a driving means operatively connected to said laterally moveable barrier means, the pressure applied to the perimeter of the flat, thin, disc-like media being controlled solely by the amount of electric current applied to the driving means,    wherein the improvement comprises the addition of biasing means which operate to apply a grasping pressure to the wafer if delivery of controlling electrical current to the driving means is interrupted.