Pneumatically actuated flexure gripper for wafer handling robots

#1. Field of the Invention

#The present invention relates to a clamping mechanism that secures a workpiece to a mechanical arm. More particularly, the present invention relates to a clamp that gently secures a semiconductor wafer to a robot blade by biasing the wafer against a retaining member at the forward edge of the blade when the robot blade is at least partially retracted for rotation. The clamp is actuated by a pneumatic cylinder and utilizes a flexure member to maintain a desirable clamping force against the wafer.

#2. Background of the Related Art

#So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.

#It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

#FIG. 1 is a top schematic view of a “polar” type robot arm for wafer handling showing the robot in retracted position and also showing the robot in extended position in phantom.

#FIG. 1 is a schematic view of a “polar” type robot shown in a retracted position and shown in phantom in an extended position. The robot 10 includes a single robot arm 42 including a first strut 44 rigidly connected to a drive member 20. A second strut 45 of the robot arm 42 is pivotally connected to the first strut 44 by an elbow pivot 46 and by a wrist pivot 50 to a workpiece handling member 60. The structure of struts, 44 and 45, and pivots, 46 and 50, form a “polar” type robot arm 42 connecting the wafer handling member 60 to the drive member 20.

#Basic operation of “polar” type robots are conventional. First strut 44 moves rotationally in one of two modes. In a rotational mode, a linkage between the drive member 20 and second strut 45 and wafer handling member 60, is disengaged so that upon rotation of first strut 44, the entire robot arm 42 rotates without extension or retraction. In an extension mode, a linkage between the drive member 20 and second struts 45 and wafer handling member 60 is engaged so that, for example, as first strut 44 rotates clockwise, second strut 45 rotates counterclockwise and wafer handling member 60 rotates clockwise. This counter-rotation of the respective struts causes extension of the wafer handling member 60 with respect to the robot 10. Reversal of the drive 20 causes first and second struts 44, 45 and wafer handling member 60 to rotate in the reverse directions to cause retraction of the wafer handling member 60.

#FIG. 2 shows a schematic diagram of an exemplary integrated cluster tool 400 useful for processing wafers 302 in tandem. Wafers 302 are introduced into and withdrawn from the cluster tool 400 through a loadlock chamber 402. A robot 10 having a pair of wafer handling blades 64 is located within the cluster tool 400 to transfer the substrates between the loadlock chamber 402 and the various process chambers 404. The robot arms 42 are illustrated in a retracted position so that the robot assembly can rotate freely within the transfer chamber 406. The specific configuration of the cluster tool in FIG. 2 is merely illustrative and the system shown is capable of processing two wafers 302 at one time. However, the invention is equally applicable to single wafer transfer or robot assemblies such as the “polar” type robot described above and shown in FIG. 1. In a preferred aspect of the invention, a microprocessor controller is provided to control the fabricating process sequence, conditions within the cluster tool, and operation of the robot 10.