BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, and like reference numerals designate like structural elements.
FIGS. 1 and 2 are isometric and profile views showing a conventional load port configured to interface with a standard 300 mm, 25-wafer pod.
FIG. 3 shows an isometric view of an exemplary bridge loadport.
FIGS. 4A and 4B show embodiments of a load port for the bridge loadport of FIG. 3.
FIGS. 5, 6, 7, and 8 show schematic representations of the loadport of FIG. 4B in various stages of operation.
FIG. 9 shows a schematic representation of a control system for the bridge loadport of FIG. 3.
FIGS. 10A, 10B, 10C, and 10D show the bridge loadport of FIG. 3 in various configurations.
DETAILED DESCRIPTION
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without some of these specific details. In other instances, well known process operations and implementation details have not been described in detail in order to avoid unnecessarily obscuring the invention.
FIG. 3 shows an exemplary bridge loadport 100 having a tool interface 120 having a generally vertically extending plate. In one embodiment, tool interface 120 conforms to an industry standard BOLTS interface, and is configured to substantially cover one end of a process tool, such as process tool 40 shown in FIG. 1. Bridge loadport 100 also includes an advance plate assembly 150 having an advance plate 152 for mounting a pod as described in further detail below. Advance plate assembly 150 includes an elevator mechanism 156 configured to raise and lower advance plate 152 for purposes that will be made clear below with reference to FIGS. 10A-10D. In one embodiment, elevator mechanism 156 is implemented using a linear actuator, such as a belt drive, lead screw, or other servo actuator as would occur to those skilled in the art. In addition, advance plate assembly 150 includes an internal actuator for moving the advance plate 152 from a retracted position, which is spaced from tool interface 120 to an advanced position, proximate tool interface 120.
Bridge loadport 100 also includes a load port 105 having a port plate 140. Port plate 140 defines an aperture 142 that is shown substantially occluded by port door face 132 of port door 130. In one embodiment, port plate 140 is attached to a frame (not visible in FIG. 3) of bridge loadport 100 using a releasable attaching means such as a plurality of screws or one or more latches. A partial cross section view of loadport 105 is shown in FIG. 4A. It can be seen here that port plate 140 is attached to frame 145 by screws 147. In addition, port door face 132 is retained to port door actuator 136 by a coupling. In one embodiment, the coupling simply fixes port door face 132 to port door actuator 136 in the absence of springs 134. For example, the coupling could include a plurality of screws, latches, clips, etc. In another embodiment, the coupling allows for relative movement between port door face 132 and port door actuator 136. In this embodiment, the coupling could include one or more alignment means which permit relative movement only in the direction perpendicular to the plane of the port door face.
Such alignment means may be formed by the axial shafts of the two latch keys 160, in combination with corresponding surfaces in the port door, or additional alignment means (not shown) may be provided such as a linear bearing, alignment pins, etc., to ensure port door face smoothly moves with one degree of freedom along a single axis perpendicular to port door actuator 130, substantially preventing rotational movement or translational movements along other axes. The additional alignment means can also include a catch for retaining port door face 132 to port door 136. In either embodiment, the coupling may be cooperative with any of a plurality of port door faces of differing sizes and shapes, depending on the size of pod 70.
Although represented as helical springs, springs 134 may be implemented in any suitable fashion, and may, for example, be formed integrally with port door face 132 or port door actuator 136. Port door face, e.g., may be made from a suitable plastic material, wherein at least the front surface is formed from a material sufficiently stiff to meet flatness standards promulgated for process tool interface port doors by Semiconductor Equipment and Materials International (SEMI). In one embodiment, port door face 132 includes an extended rim 138, shaped to improve the air flow and resulting proximity seal between port door face 132 and aperture 142 of port plate 140.
Pod 70 includes an interior space 73 enclosed by a pod door 74. Pod door 74 includes, for each latch key 160, a latch key receptacle 80 (only one being visible in FIG. 4A) having an internal shoulder 82. In FIG. 4A, pod 70 is mounted to a support 75 capable of moving left and right to advance pod 70 to port plate 140 for loading and to retract pod 70 from port plate 140 for unloading. FIG. 4B shows a second embodiment wherein pod 70 is mounted to an advance plate 152, which is moved left and right by advance plate assembly 150, which is shown in more detail in FIG. 3.
FIGS. 5-8 show various stages of operation of load port 105. It should be noted that these operations apply both to the embodiments of FIG. 4A and FIG. 4B. In FIG. 5, the pod support, in this case advance plate 152, is moved to the advanced position, thereby bringing front flange 79 of pod 70 to port plate 140. In one embodiment, front flange 70 is brought sufficiently close to port plate 140 to form a proximity seal therewith.
In one embodiment, port door actuator 136 moves forward after pod 70 is moved to the advanced position, the forward movement of port door actuator 136 causing springs 134 to compress and latch keys 160 to be extended into latch key receptacles 80. In another embodiment, port door actuator 36 is moved into the forward position prior to or during the advance of pod 70. In either case, latch keys 160 are inserted into latch key receptacles 80 and springs 134 are in a compressed state, biasing port door face 132 into engagement with pod door 74. The movement of port door actuator is effectuated by mechanism 135 shown by way of example in FIG. 4A. Mechanism 135 is capable of moving port door 130 on a Y and a Z axis, the Y-axis being left and right as viewed in FIG. 5, and the Z-axis being up and down.
In FIG. 6, latch key 160 is rotated 90° to unlatch the pod door from the pod. Port door actuator 136 includes an actuator mechanism (not shown) such as a servo or solenoid causing latch key 160 to rotate. Rotation of latch key 160 interacts with an internal mechanism (not shown) in pod door 74. The internal mechanism causes pod door latches to retract from slots (not shown) formed in lip 76 of pod 70, thereby releasing pod door 74 from pod 70. Such a mechanism is described in more detail in U.S. Pat. Nos. 4,995,430 and 6,502,869, previously incorporated herein by reference. In addition, the rotation of latch keys 160 cause the pod door 74 to be coupled to port door 30, due to interference between cross bar 164 (see FIG. 4A) and internal shoulder 82 of pod door 74.
In FIG. 7, port door 130 is shown moved a small distance away from aperture 142, allowing springs 13 to decompress slightly. In the position shown in FIG. 7, the back edges of cross bar 164 (FIGS. 4A, 4B, 5) of latch key 160 just engage internal shoulders 82 of latch key receptacles 80 formed in pod door 74. Note that springs 134 remain in a compressed state, exerting a force against port door face 132, which in turn is pressed against pod door 74. Resulting friction between port door face 132 and pod door 74 ensures that there is no relative movement between pod door 74 and port door face 132. Port door actuator 136 continues to move in a rearward direction from the position shown in FIG. 7, as shown in FIG. 8, wherein pod door 74 is removed entirely away from pod 70. From this position, port door 30, along with pod door 74, may move down using an actuator such as actuator 132 shown in FIG. 4A. Once port door 30 is moved down, access to substrates 78 in pod 70 becomes substantially unobstructed either by pod door 74 or port door 30.
Replacement of pod door 74 can be achieved by performing, in reverse, the steps described above with reference to FIGS. 4B through 8. Specifically, port door actuator 130 is moved forward from the position shown in FIG. 8 until pod door 74 is positioned within pod lip 76, as shown in FIG. 7. Then, port door actuator 130 continues its forward movement until cross bar 164 of latch key 160 disengages from internal shoulder 82 in latch key receptacle 80, as shown in FIG. 6. Then, the latch key is rotated 90° to a vertical position shown in FIG. 5, causing the pod door 74 to engage lip 76 of pod 70. Then, advance plate 152 retracts to the retracted position shown in FIG. 4B, and optionally, port door actuator 136 moves to a retracted position.
FIG. 9 shows an exemplary control system 190 for controlling the operations of bridge loadport 100, described above with reference to FIGS. 3-8. Control system 190 includes a control unit 192 which is in communication with an external control system 195. In one embodiment, external control system 195 may provide load and unload directives to control unit 192, in response to which control unit 192 operates bridge loadport 100 to load and unload a pod. Advance plate assembly 150 (or other support system such as support 75 shown in FIG. 4A) includes an advance actuator 153 for moving the pod 70 between the retracted and advanced positions described previously. Advance plate assembly 150 may include a pod sensor 155 that detects a presence of a pod on the advance plate. For example, pod sensor 155 may be implemented using a microswitch or a proximity sensor to detect when a pod is properly mounted on advance plate 152. Pod sensor 155 may further be adapted to sense the particular type or configuration of pod which has been placed on the loadport, or the loadport control unit 192 may receive a signal from the external control system 195 conveying such information.
Upon receiving a “load” directive from external control system 195, control unit 192 detects whether a pod is mounted by way of pod sensor 155, then causes advance plate 152 to move to the advanced position (shown, e.g., in FIG. 5) by activating advance actuator 153. Control unit 192 also actuates port door mechanism 132 (shown in FIG. 4A) to cause the port door actuator 136 to move forward so that the latch keys 160 extend into latch key receptacles 80 as shown in FIG. 5. Control unit 192 then causes port door actuator 136 to rotate the latch keys 160 to disengage pod door 74 from outer lip 76 of pod 70. Control unit 192 then actuates port door mechanism 32 to cause port door 30 to move from the closed position to the open position described above. These operations are performed substantially in reverse upon receipt by control unit 190 of an “unload” directive from external control system 195. In one embodiment, control unit 192 also operates elevator 156 shown in FIG. 3, to raise and lower advance plate assembly 150, for reasons that will be made clear in the discussion below referencing FIGS. 10A-10D.
Bridge loadport 100 described above may be easily reconfigured for different size pods by replacing port plate 140 and port door face 132. FIGS. 10A-10D show exemplary configurations. In FIG. 10A, bridge loadport 100 includes a port plate 140′ having an aperture 142′ sufficiently tall and wide to accommodate a large capacity pod designed to contain a maximum of 25 450 mm wafers. In FIG. 10B, bridge loadport 100 includes a port plate 140″ having an aperture 142″ sufficiently tall and wide to accommodate a low capacity pod designed to contain a maximum of 10 wafers 450 mm wafers. Since a pod of this capacity has a lower profile, advance plate assembly 150 is lifted from the position shown in FIG. 10A to ensure alignment between the pod door and port door face 132 and between latch keys 160 and the latch key receptacles formed on the pod.
Advance plate assembly 150 may be lifted by elevator 156 shown by way of example in FIG. 3. In one embodiment, elevator 156 is manually operated, e.g., by using a manually operated vertically adjustable support or by manually removing advance plate assembly 150 from a first location on and reattaching advance plate assembly 150 to load port 100 at a different elevation. In another embodiment, elevator 156 is automatically adjusted in response to signals from control unit 192 (FIG. 9).
In FIG. 10C, bridge loadport 100 includes a port plate 140′″ having an aperture 142′″ sized to correspond with a low capacity pod designed to contain a maximum of 10 wafers each 300 mm in diameter. Since these wafers have a smaller diameter, the pod used to transport them is not as wide, and therefore aperture 142′″ is not as wide as the apertures 142′ and 142″ shown in FIGS. 10A and 10B, respectively. FIG. 10D shows a bridge loadport 100 configured to cooperate with a standard 25 300 mm wafer, pod, substantially as shown in FIG. 3, but presented again here for comparison with configurations in FIGS. 10A-10C.
While FIGS. 10A through 10D show by way of example, pods and loadports configured for receiving and storing semiconductor wafers, other substrate types, such as magnetic media, LCD panels, etc., can be received and stored using loadports and pods as described above. It should also be recognized that various mechanisms, aside from the spring-biased door face described above with reference to FIGS. 4-8, may be used to retain a pod door to the port door. For example, suction means, or the twist and pull latch key mechanism described in the above-mentioned U.S. Pat. No. 6,502,869. The interchangeable port plates and port door faces allows easy reconfiguration of a load port that is initially configured to receive pods of a first size to be subsequently configured to receive pods of a second size, wherein the first and second pod sizes can differ with respect to a lot size difference, a substrate dimension difference, or both.
Although the foregoing invention has been described in some detail for purposes of clarity of understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.
Patent Application
20080008570
