Abstract:
An end effector for a pod loader interface includes a gripper plate that attaches to the articulated arm. A pair of gripper blades are separated from each other along and are coupled to the gripper plate. During gripping of a wafer carrier, the gripper blades initially close toward each other and then draw nearer to the gripper plate. Nested outer and inner U-shaped yokes, which may attach the gripper plate to the articulated arm, are joined by rotational joints to permit their relative rotation for reorienting the wafer carrier. Yet other aspect of the present invention are a mechanical forearm drive that provides substantially linear motion of an articulated arm&#39;s wrist joint, and an end effector rotary-drive included in a forearm of the articulated arm.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part of application Ser. No. 09/343,110 that was filed Jun. 29, 1999, which issued Jul. 11, 2000, as U.S. Pat. No. 6,086,323, that is a continuation of application Ser. No. 08/400,039 filed Mar. 7, 1995, which issued Nov. 16, 1999, as U.S. Pat. No. 5,984,610. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to silicon wafer handling machines, and more particularly is a pod loader interface that is adapted to unload and reload SMIF (Standard Mechanical InterFace) pods. 
     2. Description of the Prior Art 
     Handling of silicon wafers is critical to the integrated circuit (IC) manufacturing process. Any physical damage to the wafers will, of course, decrease the chip yield, which is a prime consideration in the profitability of semiconductor manufacturing. Contamination of the wafer by particulate or other contaminants also decrease chip yield. For several decades the semiconductor manufacturing industry has addressed its need to reduce contamination during manufacturing by replacing human operators, as much as practicable, with robot wafer handling equipment. 
     The desire to shield wafers from contaminants has led the semiconductor industry to the development and use of SMIF pods. SMIF pods allow wafers to be transported in a clean, sealed environment, so they are not exposed to ambient air. 
     Once the SMIF pods reach their destination, they must be opened, and the wafer carrier inside must be placed in position for the desired process operation. If the unloading and positioning operation is performed manually, the wafers are subjected to the usual risk of damage from mishandling as well as increased exposure to contamination. 
     Pod loader interfaces are used extensively in the semiconductor industry to automatically unload a SMIF pod and position the wafers held in a wafer carrier for the next process operation, and then reload the wafers and the wafer carrier when the process step is completed. In general, these pod loader interfaces include an arm for transporting the wafer carrier and wafers between a clean mini-environment established within the pod loader interface and the processing tool which performs the process step. The arm of the pod loader interface includes an end effector that grasps and secures the wafer carrier. 
     One difficulty experienced in integrating a pod loader interface with a semiconductor processing tool is mechanically aligning the interface and the tool so the end effector may reliably grasp and secure a wafer carrier present within the processing tool and/or pod loader interface. It is also advantageous if a pod loader interface can be readily adapted to deliver wafer carriers to semiconductor processing tools in any arbitrarily chosen orientation. 
     BRIEF SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a means to more reliably automatically open and unload, and subsequently reload and close, a SMIF pod. 
     Another object of the present invention is to provide an end effector for an arm of a pod loader interface that relaxes alignment tolerances between the pod loader interface and the semiconductor processing tool. 
     Yet another object of the present invention is to provide an end effector for an arm included in a pod loader interface that readily accommodates varying positions for wafer carriers in semiconductor processing tools. 
     Briefly, the present invention in one aspect is an end effector for a pod loader interface that automatically opens a SMIF pod and unloads the contents thereof. The pod loader interface includes an elevator that raises a SMIF pod cover away from a SMIF pod base to reveal the wafer carrier contained within the sealed SMIF pod. An articulated arm of the pod loader interface thereafter reaches through an opening in a bulkhead thereof, secures the wafer carrier and withdraws it through the bulkhead opening. The wafer carrier is then placed at a location within the processing tool where it can be operated upon by the processing tool to perform a step in the manufacturing process. The pod loader interface includes an integrated clean air system to maintain the wafers in a clean environment. 
     A specific aspect if the present invention is an end effector, attached to the articulated arm of the pod loader interface, that grips the wafer carrier. This end effector includes a gripper plate that attaches to the articulated arm. Aligning means secured to the gripper plate properly align the end effector with the wafer carrier. A pair of gripper blades are separated from each other along and are coupled to the gripper plate. During gripping of the wafer carrier by this end effector, the gripper blades initially close toward each other and then draw nearer to the gripper plate. The end effector also includes drive means, that is secured to the gripper plate, which energize movement of the gripper blades for gripping the wafer carrier. By drawing the gripper blades nearer to the gripper plate, this end effector accommodates greater variations among wafer carrier positions both within the pod loader interface and within the processing tool. 
     Another aspect of the present invention is an end effector which also includes an outer and an inner nested pair of U-shaped yokes which attach the gripper plate to the articulated arm. Each of the U-shaped yokes has a base from opposite ends of which extend two parallel sides. The base of the outer U-shaped yoke attaches directly to the articulated arm. To permit relative rotation of the U-shaped yokes with respect to each other, the outer and inner U-shaped yokes are joined by rotational joints located at ends of each of the sides furthest from their bases. The gripper plate, preferably that described in the preceding paragraph, is fastened to the base of the inner U-shaped yoke between the sides thereof. This end effector also includes a carrier rotary-drive that is coupled between the U-shaped yokes to energizes rotation of the outer and inner U-shaped yokes with respect to each other. In this way, the end effector may rotate a wafer carrier that is gripped by the gripper blades about an axis that: 
     1. passes through the rotational joints between ends of the sides of the U-shaped yokes; and 
     2. is oriented parallel to semiconductor wafers held in the wafer carrier. 
     Yet another aspect of the present invention is an improved mechanical rotary drive for a forearm of the articulated arm. In this improved rotary drive, a notched belt, formed into a continuous loop and tensed by a differential screw that joins ends of the belt, couples together pulleys that are located at the shoulder and elbow joints of the articulated arm. Respective diameters of the pulleys and lengths of the upper arm and forearm are arranged so rotation of the upper arm about the shoulder joint effects substantially straight line motion of the wrist joint during transportation of the wafer carrier. 
     Yet another aspect of the present invention is an end effector rotary-drive included in a forearm of the articulated arm. The end effector rotary-drive is coupled through a wrist joint of the forearm to the gripper plate of the end effector. In this way, the end effector rotary-drive can independently rotate the gripper plate with respect to the forearm about an axis that is oriented perpendicular to a plane in which the wrist joint moves when the articulated arm transports semiconductor wafers held in the wafer carrier to or from the processing tool. 
     These and other features, objects and advantages will be understood or apparent to those of ordinary skill in the art from the following detailed description of the preferred embodiment as illustrated in the various drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of the pod loader interface in accordance with the present invention; 
     FIG. 2 is a rear perspective view of the pod loader interface in accordance with the present invention; 
     FIG. 3 is a front perspective view of the pod loader interface in accordance with the present invention in a raised position; 
     FIG. 4 is a perspective view of an prior configuration for an end effector used in the pod loader interface; 
     FIG. 5 is an underside view of the prior configuration end effector depicted in FIG. 4; 
     FIG. 6 is an exposed, perspective view of a gripper included in an end effector in accordance with the present invention that is adapted for use in the pod loader interface; 
     FIGS. 7A-7D are side elevational views which schematically illustrate movement of a gripper blade included in the gripper E depicted in FIG. 6; 
     FIGS. 8A and 8B are respectively side and end elevational views illustrates U-shaped yokes that permit rotating a wafer carrier about an axis that is parallel to semiconductor wafers held therein; 
     FIG. 9 is a cutaway perspective view depicting a portion of an articulated arm in accordance with the present invention; 
     FIGS. 10A-10C are plan views which schematically illustrate extension of the articulated arm depicted in FIG. 9 from a home position; 
     FIG. 11 is a graph showing deviation from straight line motion exhibited by a wrist joint of the articulated arm depicted in FIG. 9; and 
     FIG. 12 is a cutaway perspective view depicting a portion of a forearm included in the articulated arm taken along the line  10 — 10  in FIG.  9 . 
    
    
     DETAILED DESCRIPTION 
     The present invention is a pod loader interface  10 . Referring now to FIGS. 1 through 3, it can be seen that the machine comprises a supporting bulkhead  12 , an elevator  14 , a loading platform  16 , and an articulated arm  18 . The loading platform  16  is adapted to receive a SMIF pod  20 . An unlocking mechanism is contained in the loading platform  16  to release the mechanism locking a base  201  to the cover  202  of the SMIF pod  20 . Means to perform the unlocking procedure are well known in the art, and thus are not described in detail herein or illustrated in the drawings. 
     The elevator  14  is the means used to remove the cover  202  from the SMIF pod  20 . Clamps  141 , that in a prior configuration of the pod loader interface  10  were controlled by air cylinders  142 , are used to secure the SMIF pod  20  in position on the elevator  14  before the elevator  14  is raised to open the SMIF pod  20 . In the presently preferred configuration of the pod loader interface  10 , electric actuators control the clamps  141 . 
     An elevator drive mechanism  22  raises and lowers the elevator  14 . The elevator drive mechanism  22  includes a motor  221  which turns, via a belt-and-pulley linkage, a lead screw  222 . The lead screw  222  is affixed via two mounting blocks  223  to the bulkhead  12 . In a prior configuration of the pod loader interface  10 , an elevator carriage  224  travels up and down along two guide rails  225 . In this prior configuration, the carriage  224  is affixed to the elevator  14  by two connecting arms. The connecting arms slide along slots  227  in the rear of the bulkhead  12 , allowing the elevator  14  to be raised and lowered. In the presently preferred configuration of the pod loader interface  10 , the elevator carriage  224  travels up and down along a single guide rail, and the motor  221  is a stepper motor that employs closed-loop feedback. 
     The articulated arm  18  is the means used to grasp and move a wafer carrier  24  contained within the SMIF pod  20 . The arm  18  includes pivoting shoulder  181 , elbow  182 , and wrist  183  joints to allow a complete range of motion in the horizontal direction. The arm  18  includes an upper arm  185  which extends between the shoulder joint  181  and the elbow joint  182 , and a forearm  187  which extends between the elbow joint  182  and the wrist joint  183 . 
     An arm vertical drive  26  permits the arm  18  to raise and lower the wafer carrier  24  vertically. The vertical drive  26  includes a second motor  261  which turns, via a belt-and-pulley linkage, a lead screw  262 . The lead screw  262  is affixed to the bulkhead  12  via a mounting block  263 . A bearing assembly  264  affixed to an arm carriage  265  allows the lead screw  262  to drive the arm carriage  265  up and down. In a prior configuration of the pod loader interface  10 , the arm carriage  265  travels up and down along two guide rails  266 . The arm carriage  265  is affixed to an upper end of the articulated arm  18 , so that the arm  18  moves up and down with the carriage  265 . In the presently preferred configuration of the pod loader interface  10 , the arm carriage  265  travels up and down along a single guide rail, and the second motor  261  is a stepper motor that employs closed-loop feedback. 
     The arm carriage  265  also supports a third motor  267  which provides the impetus for the horizontal travel means of the articulated arm  18 . The third motor  267  also uses a belt-and-pulley linkage to transmit rotational force to the arm  18 . In the presently preferred configuration of the pod loader interface  10 , the third motor  267  is also a stepper motor that employs closed-loop feedback. 
     An end effector  28  affixed to an end of the arm  18  allows the machine to grasp and secure the wafer carrier  24 . In the prior configuration of the pod loader interface  10 , the gripping means  281  are extended and retracted by air cylinders. 
     FIGS. 4 and 5 depict in greater detail a prior configuration for the end effector  28 . The open position of the gripping means  281  of this prior configuration is shown in phantom in FIG.  4 . This prior configuration of the pod loader interface  10  attaches the end effector  28  to the articulated arm  18  by a leaf spring assembly  282 . A sensing means  283  installed on an upper surface of the end effector  28  permits the pod loader interface  10  to determine when the end effector  28  contacts the wafer carrier  24 . In the prior configuration of the pod loader interface  10 , the sensing means  283  is a thin film piezoelectric sensor. 
     FIG. 5 shows the aligning means  284  installed on an underside of the end effector  28 . The aligning means  284  in the preferred embodiment is a set of four blocks situated around a center point. The blocks each have a tapered inner side surface  285  that creates a funneling means to guide the handle (not shown) on the wafer carrier to a centered position with respect to the end effector  28 . If the alignment of the handle, and hence the carrier, is not perfectly centered when the end effector  28  is pushed onto it, the guide blocks direct the carrier into an exactly centered position. Precise details of the arrangement for the blocks and the tapered inner surface  285  vary depending upon the specific type of wafer carrier  24  with which they are adapted to mate. 
     FIG. 6 depicts an embodiment of a gripper  2802  in accordance with the present invention that is preferably used in the end effector  28 . The gripper  2802  includes a gripper mounting plate  2804  to opposite ends of which are coupled a pair of L-shaped gripper blades  2806 . Pivoting joints couple each of the gripper blades  2806 , a pair of side links  2812 , a center actuation link  2814 , and a linkage mounting block  2816  into a well known four-bar linkage structure. Each of the linkage mounting blocks  2816 , which are securely fastened to the gripper mounting plate  2804 , are oriented to establish rotationally symmetric four-bar linkage structures at opposite ends of the gripper mounting plate  2804 . A pair of ball-end push rods  2822  respectively couple each of the center actuation links  2814  to a centrally located worm drive wheel  2824 . 
     From an initial orientation of the worm drive wheel  2824  illustrated in FIG. 6, clockwise rotation of the worm drive wheel  2824  drives the push rods  2822  in opposite directions outward toward the respective linkage mounting blocks  2816 . A theoretical analysis depicted in FIGS. 7A-7D schematically illustrates movement of one of the gripper blades  2806  with respect to the gripper mounting plate  2804  as the four-bar linkage pivots in response to clockwise rotation of the worm drive wheel  2824 . Before the worm drive wheel  2824  begins rotating, as illustrated in FIG. 7A the center actuation link  2814  is oriented an at angle of approximately  1540  with respect to an axis  2832  that is perpendicular to the gripper mounting plate  2804 . As the push rods  2822  are initially driven outward by rotation of the worm drive wheel  2824 , the center actuation link  2814  pivots from its initial orientation depicted in FIG. 7A to a position depicted in FIG. 7C in which the center actuation link  2814  is oriented at an angle of approximately 132.5° with respect to the axis  2832 . As indicated graphically in FIGS. 7A-7C, this initial movement of the center actuation link  2814  causes the gripper blades  2806 , respectively located at opposite ends of the gripper mounting plate  2804 , to pivot closer to each other, and toward a wafer carrier  24  if it were located between the gripper blades  2806 . 
     From the position illustrated in FIG. 7C, continued clockwise rotation of the worm drive wheel  2824  moves each center actuation link  2814  to the position illustrated in FIG. 7D in which the center actuation link  2814  is oriented at an angle of approximately  111 . 070  with respect to the axis  2832 . This further movement of the center actuation link  2814  from the orientation illustrated in FIG. 7C to that illustrated in FIG. 7D causes the gripper blade  2806  to draw nearer to the gripper mounting plate  2804 . If a wafer carrier  24  were located between the gripper blades  2806 , this final movement of the gripper blades  2806  toward the gripper mounting plate  2804 , causes them to engage a flange of the wafer carrier  24 , graphically illustrated in FIGS. 7A-7D by a rectangle  2834 . 
     Referring again to FIG. 6, the gripper  2802  also includes a bi-directional electric motor  2842  that is secured to the gripper mounting plate  2804 . A shaft  2844  of the electric motor  2842  is coupled to a driving worm that is supported on bearings within a worm drive mounting-block  2846 . Operation of the electric motor  2842  indirectly energizes movement of the gripper blades  2806  through rotation of the worm drive wheel  2824  which extends outward and retracts inward the push rods  2822 . 
     The gripper  2802  also includes a optical worm-drive-wheel orientation-sensor  2852  to permit sensing when the gripper blades  2806  are properly positioned to engage a wafer carrier  24  as illustrated in FIG.  7 D. When the worm drive wheel  2824  is in a pre-established orientation in which the gripper blades  2806  properly engage a wafer carrier  24 , a shutter that projects radially outward from the worm drive wheel  2824 , not illustrated in any of the FIGS., interrupts two (2) light beams which propagate within the orientation-sensor  2852 . If something halts movement of the gripper blades  2806  before the worm drive wheel  2824  rotates to the pre-established orientation, or if the worm drive wheel  2824  rotates into an orientation beyond the pre-established orientation, then electrical signals from the orientation-sensor  2852  indicate that the gripper  2802  is not properly engaging the wafer carrier  24 . 
     To impede contamination of wafers present in a wafer carrier  24  held by the gripper  2802 , the preferred end effector  28  houses everything depicted in FIG. 6 except ends of the L-shaped gripper blades  2806  within an enclosure that is not illustrated in any of the FIGS. A surface of this enclosure located between the gripper blades  2806  carries the aligning means  284  depicted in FIG.  5 . The preferred end effector  28  also includes a pair of micro-switches, not illustrated in any of the FIGS., that are spaced apart on the enclosure for detecting initial engagement of the end effector  28  with a wafer carrier  24 . 
     Because movement of the gripper blades  2806  toward the gripper mounting plate  2804  as illustrated in FIGS. 7C and 7D permits the gripper  2802  to more readily accommodate varying positions for the wafer carrier  24  present in a semiconductor processing tool, the gripper  2802  may attach directly to the wrist joint  183  of the arm  18  omitting the leaf spring assembly  282 . However, to permit re-orienting semiconductor wafers held in the wafer carrier  24  while they are being transferred between the pod loader interface  10  and the processing tool, as illustrated in FIGS. 8A and 8B the end effector  28  may also include a U-shaped outer yoke  2862  within which nests a U-shaped inner yoke  2864 . The outer yoke  2862  includes a base  2866  from opposite ends of which extend two parallel sides  2868   a  and  2868   b . The base  2866  of the outer yoke  2862  attaches directly to the wrist joint  183  of the arm  18 . The inner yoke  2864  also includes a base  2872  from opposite ends of which extend two parallel sides  2874   a  and  2874   b . The gripper  2802  including the gripper mounting plate  2804  are incorporated into the base  2872  of the inner yoke  2864  between the sides  2874   a  and  2874   b . Thus the outer yoke  2862  and the inner yoke  2864  attach the gripper  2802  to the arm  18 . 
     The outer yoke  2862  and the inner yoke  2864  are joined to each other by rotational joints  2876  that are located between ends of sides  2868   a  and  2868   b  and sides  2874   a  and  2874   b  that are furthest from the base  2866  and the base  2872 . As indicated by a curved arrow  2878  in FIG.  8 B and the phantom illustration of the inner yoke  2864 , the rotational joints  2876  permit relative rotation of the inner yoke  2864  with respect to the outer yoke  2862  about an axis  2882  that: 
     1. passes through the rotational joints  2876 ; and 
     2. is oriented parallel to semiconductor wafers carried in a wafer carrier  24  held by the gripper  2802 . 
     A yoke rotary-drive  2886 , that includes an electric motor located in the base  2866  and a transmission located in the side  2868   a , is coupled between the outer yoke  2862  and the inner yoke  2864  to energize rotation of the inner yoke  2864  with respect to the outer yoke  2862 . 
     In addition to reorienting wafers held in the wafer carrier  24 , rotation of the inner yoke  2864  with respect to the outer yoke  2862  about an axis  2882  that is oriented parallel to semiconductor wafers held in a wafer carrier  24  may be exploited advantageously to reduce the possibility that wafers might fall out of the wafer carrier  24  during horizontal motion, or “rattle”, in the wafer carrier  24  during vertical motion. Furthermore, appropriately tilting the wafer carrier  24  to an angle that exceeds 20° from the horizontal re-seats wafers in the wafer carrier  24  thus forestalling the possibility of damage while the cover  202  closes onto the base  201  of the SMIF pod  20 . 
     FIG. 9 illustrates a presently preferred embodiment for a forearm rotary drive that is enclosed within the upper arm  185  of the arm  18 . The forearm rotary drive includes a shoulder pulley  1804  that is located within the upper arm  185  and fixed through the shoulder joint  181  to the bulkhead  12 . The forearm rotary drive also includes an elbow pulley  1806  that is also located within the upper arm  185  and fixed through the wrist joint  183  to the forearm  187 . A toothed timing belt  1808 , also located within the upper arm  185 , couples the shoulder pulley  1804  and the elbow pulley  1806  to each other. Tension is applied to the toothed timing belt  1808  and its ends are coupled together by a differential screw  1812  which mates with and engages belt clamps  1814  that are respectively secured to each end of the toothed timing belt  1808 . 
     The following equation expresses the deviation from straight line motion for the wrist joint  183  of the arm  18  which may be obtained as the upper arm  185  rotates with respect to the bulkhead  12  as depicted in FIGS. 10A-10C.        Deviation   =       L1   ·     cos        (   θ   )         -     L2   ·     cos        [     θ   ·     (       R   r     -   1     )       ]         -     (     L1   -   L2     )                              
     Where: 
     θ=angular rotation in radians of the upper arm  185  with respect to the bulkhead  12 . 
     L 1 =length of the upper arm  185 , 9.35 in. 
     L 2 =length of the forearm  187 , 4.67 in. 
     R=radius of the shoulder pulley  1804  or the number of teeth on the shoulder pulley  1804 , 54 teeth. 
     r=radius of the elbow pulley  1806  or the number of teeth on the elbow pulley  1806 , 22 teeth. 
     FIG. 11, which graphically illustrates the difference between the preceding expression and straight line motion, indicates that the wrist joint  183  deviates less than 0.040 inches from straight line motion throughout the entire motion of the arm  18  on either side of the bulkhead  12  since, as illustrated in FIG. 10 c , θ is usually less than 0.8 radians. 
     Referring now to FIG. 12, the forearm  187  of the arm  18  includes an end effector rotary-drive which is coupled through the wrist joint  183  either directly, or indirectly through the outer yoke  2862  and the inner yoke  2864 , to the gripper mounting plate  2804 . The end effector rotary-drive includes a continuous, toothed belt  1832  which encircles a large diameter driven pulley  1834  and a smaller diameter driving pulley  1836 . FIG. 12 also depicts a wire guide  1838  that is juxtaposed with one side of the driven pulley  1834  to protect electrical wires which pass through the wrist joint  183  to the end effector  28 . Arranged this way, the driven pulley  1834  can be energized to rotate the end effector  28  about an axis that is oriented perpendicular to a plane in which the wrist joint  183  moves when the arm  18  transports semiconductor wafers held in the wafer carrier  24 . 
     An adjustable idler wheel  1842  maintains tension in the belt  1832 . Rotation of the driving pulley  1836  to drive the driven pulley  1834  is energized by a stepper motor  1844  which is coupled to the driving pulley  1836  through a reduction gear drive. The end effector rotary-drive also includes an encoder  1846  also driven by the reduction gear drive to sense rotation of the end effector  28  with respect to the forearm  187  which may be as much as ±200° with respect to a home position. The ability to rotate the about an axis that is oriented perpendicular to a plane in which the wrist joint  183  moves may be exploited advantageous in gripping a wafer carrier  24  that may be slightly mispositioned within the processing tool and/or pod loader interface. 
     The pod loader interface also includes an integrated air flow system to provide filtered air to maintain a clean mini-environment. Components of the air flow system  30  for a prior configuration of the pod loader interface  10  are depicted in FIG.  3 . In that prior configuration, a fan installed in a fan housing  301  draws air in from the surrounding atmosphere. The air flows upward through a manifold  302 . The manifold feeds the air into a filter contained in the filter housing  303  to remove any particulate matter. The air then flows upward through a plenum chamber  304  contained in the housing of the loading platform  16 . The air then flows outward horizontally through a membrane contained in an inner wall of the plenum chamber  304 , so that it flows across the surface of the wafers. A presently preferred configuration for the air flow system  30  is described in U.S. Pat. No. 5,934,991 entitled “Pod Loader Interface Improved Clean Air System” that issued Aug. 10, 1999, and that is hereby incorporated by reference. A uniform velocity horizontal air flow across the surfaces of the wafers provided by the preferred air flow system  30  allows the present invention to maintain wafers in a cleaner environment than that provided by other pod loader interfaces. 
     Operation of the pod loader interface  10  to load and unload a wafer carrier is as follows: An operator places a SMIF pod  20  containing a wafer carrier  24  on the loading platform  16 . (The loading platform  16  is contained in a mini-environment to maintain cleanroom conditions.) The machine is activated, and the pod  20  is unlocked. The elevator  14  secures the clamps  141  on the cover  202  of the SMIF pod  20 . The elevator  14  raises to its highest position, as shown in FIG. 3, lifting the cover  202  away from the wafer carrier  24 . 
     The articulated arm  18  is then moved into position over the wafer carrier  24 . The gripping means  281  of the end effector  28  retract, thus securing the wafer carrier  24  to the end effector  28 . The arm  18  then lifts the wafer carrier  24  from the loading platform  16 , and places it into the proper position for the desired process operation. 
     After the manufacturing process operation is completed, the pod loader interface process reverses to re-load the wafer carrier  24  back into the SMIF pod  20  for transport to the next desired location. 
     Although the present invention has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is purely illustrative and is not to be interpreted as limiting. Consequently, without departing from the spirit and scope of the invention, various alterations, modifications, and/or alternative applications of the invention will, no doubt, be suggested to those skilled in the art after having read the preceding disclosure. Accordingly, it is intended that the following claims be interpreted as encompassing all alterations, modifications, or alternative applications as fall within the true spirit and scope of the invention.