Unequal link scara arm

Abstract

A substrate transport apparatus comprising a drive section, a controller, an upper arm, forearm and substrate holder. A proximate end of the upper arm being rotatably mounted to the drive section at a shoulder joint. A proximate end of the forearm being rotatably mounted to a distal end of the upper arm at an elbow joint. The substrate holder being rotatably mounted to a distal end of the forearm at a wrist joint. The upper arm and the forearm being unequal in length from joint center to joint center. The substrate transport arm is adapted to transport substrate to and from at least two substrate holding areas with the drive section of the transport apparatus remaining in a fixed position relative to the holding areas. Each of the upper arm, forearm and substrate holder being independently rotatable with respect to each other.

What is claimed is: 
     
         1 . A substrate transport apparatus comprising:
 an automated three link arm for selectably transporting substrates into two spaced inline substrate holding stations facing the same direction and into another at least two spaced inline substrate holding stations facing the same direction;
 wherein a wrist of the three link arm travels along parallel paths transporting substrates into each substrate holding station and a drive section of the three link arm is fixed relative to the holding stations. 
   
     
     
         2 . The substrate transport apparatus of  claim 1 , wherein the spacing between the two substrate holding stations and between any two of the at least two substrate holding stations is the same. 
     
     
         3 . The substrate transport apparatus of  claim 1 , wherein the at least two substrate holding stations comprise three spaced inline substrate holding stations including a first, second and third substrate holding station where the second substrate holding station is located between the first and third substrate holding stations and the drive section is fixed with a shoulder joint of the three link arm between the two spaced inline substrate holding stations and between the first and third substrate holding stations of the three spaced inline substrate holding stations. 
     
     
         4 . The substrate transport apparatus of  claim 3 , wherein the shoulder joint of the three link arm is located between parallel paths to the two spaced inline substrate holding stations and between parallel paths to the first and third substrate holding stations of the three spaced inline substrate holding stations so that the parallel paths to the two spaced inline substrate holding stations and the first and third substrate holding stations straddle the shoulder joint of the three link arm. 
     
     
         5 . The substrate transport apparatus of  claim 1 , wherein when a substrate moves along transport path the substrate misses a Semiconductor Equipment and Materials International exclusion area. 
     
     
         6 . The substrate transport apparatus of  claim 1 , wherein the three link arm has a minimum footprint to reach ratio for a predetermined reach. 
     
     
         7 . The substrate transport apparatus of  claim 1 , wherein the spacing between holding areas conform to Semiconductor Equipment and Materials International Standards.