Abstract:
An apparatus including a thermoformed or blow-molded tote suitable for containing a plurality of wafers in an arrangement that permits machine interaction with one or more of the plurality of the wafers within the tote. A method including loading a plurality of wafers in a thermoformed or blow-molded tote onto a tool load port of a machine; and selecting at least one of the plurality of wafers from the tote.

Description:
FIELD  
         [0001]    Shipping box containers and, more particularly, front-opening shipping boxes to ship wafers and/or wafer containing integrated circuits.  
         BACKGROUND  
         [0002]    Front-opening shipping boxes (FOSBs) are generally used to ship wafers from wafer suppliers to their customers. A FOSB may also be used within/between integrated circuits (IC) manufacturing facilities and to/from IC manufacturers. A FOSB may further be used to transfer product from an IC manufacturing facility to suppliers or customers.  
           [0003]    A FOSB may serve to directly transfer wafers from the FOSB to a front opening unified pod (FOUP) or open cassette inside an integrated circuit manufacturer facility. Wafers are generally transferred from a FOSB to a FOUP or cassette, typically, by automated methods. FOSBs for 300 millimeter wafers typically can accommodate  13  to  25  wafers.  
           [0004]    One issue with respect to current FOSBs (e.g., injection molded FOSBs) is the cost associated with the FOSB. Therefore, wafer manufacturers generally reuse FOSBs. Thus, an IC manufacturer transfers or processes the wafers from the FOSB then returns the empty FOSB to its originating point of use (e.g., IC manufacturing facilities) or a recycling center. Once the FOSB is returned to the desired location, the FOSB is cleaned and prepared for subsequent use in transferring wafers. The shipping, handling and cleaning of recycled FOSBs can add significant costs to the wafer manufacturing process.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    Features, aspects, and advantages of embodiments of the invention will become more thoroughly apparent from the following detailed description, appended claims, and accompanying drawings in which:  
         [0006]    [0006]FIG. 1 shows a perspective top view of a thermoformed front-opening shipping box (FOSB).  
         [0007]    [0007]FIG. 2 shows the FOSB of FIG. 1 with the front door removed to reveal the interior of the FOSB.  
         [0008]    [0008]FIG. 3 shows a cross-section through line A-A′ of FIG. 2 and illustrates of wafer support features on the interior of one side panel of the FOSB of FIG. 1.  
         [0009]    [0009]FIG. 4 shows a cross-section through line B-B′ of FIG. 2 and illustrates wafer support features on the interior of the FOSB of FIG. 1.  
         [0010]    [0010]FIG. 5 shows an interior side view of one wafer support shelf of one side panel of the FOSB of FIG. 1.  
         [0011]    [0011]FIG. 6 shows a first side view of the top and sides of the FOSB of FIG. 1 in a linear arrangement.  
         [0012]    [0012]FIG. 7 shows a second view of the top and side view of the FOSB of FIG. 1 in a linear arrangement.  
         [0013]    [0013]FIG. 8 shows an exploded top front perspective view of the FOSB of FIG. 1.  
         [0014]    [0014]FIG. 9 shows a flow chart of an embodiment of forming a FOSB.  
         [0015]    [0015]FIG. 10 shows a first side view of the top, bottom and sides of another embodiment of a FOSB in a planar arrangement.  
         [0016]    [0016]FIG. 11 shows the FOSB of FIG. 9 being folded into a box structure.  
         [0017]    [0017]FIG. 12 shows an embodiment of a FOSB compatible with an automated door. 
     
    
     DETAILED DESCRIPTION  
       [0018]    Referring to FIG. 1, a tote configured as a front-opening shipping box (FOSB) is shown. In one embodiment, FOSB  100  is suitable for use in shipping wafers from wafer suppliers (e.g., manufacturers) to their customers (typically integrated circuit (IC) manufacturers), within/between IC manufacturers, or from IC manufacturers to customers or suppliers. Representatively, FOSB  100  is suitable for shipping 300 millimeter (mm) wafers, typically any number up to 25 wafers.  
         [0019]    FOSB  100  is illustrated in the form of a box (e.g., a rectangular box) having door  110  (e.g., a removable door) connected to the body of the box. The body of FOSB  100  includes top  130 , base  140 , first side  150 , and second side  160 . Rear  120  is connected to the body of FOSB  100  opposite the door. In one embodiment, FOSB  100  is designed to comply with a standard technically approved by the Global Physical Interfaces and Carriers Committee. Currently, the specification governing FOSBs to ship 300 mm wafers is SEMI M31-0999, titled “Provisional Mechanical Specification for Front-Opening Shipping Box Used to Transport and Ship 300 mm Wafers,” published by Semiconductor Equipment and Materials International in 1998 and in June 1999 (www.semi.org).  
         [0020]    In one embodiment, the individual components of FOSB  100  (door  110 , rear  120 , top  130 , bottom  140 , first side  150 , and second side  160 ) are thermoformed components, such as a polymer or plastic material. Thermoforming generally describes a manufacturing of plastic parts by preheating a sheet of plastic, bringing the sheet of plastic in the contact with a mold whose shape the plastic takes. In one embodiment, one or more of the components (i.e., the body, door  110 , and rear  120 ) of FOSB  100  are formed of a two-sheet (“twinsheet”) thermoformed structure, representing interior and exterior sides of the particular components of FOSB  100  (twin-sheet). Single or multiple sheet structures are also contemplated. In another embodiment, one or more of the components of FOSB  100  are formed by blow-molding in which a polymer is extruded through a die in a tube-like fashion then pinched off by a mold that forms the part as air is injected into the cavity forcing the cylinder walls to contort to the cavity walls.  
         [0021]    Top  130 , base  140 , first side  150 , and second side  160  of FOSB  100  are formed as a single body and distinguished from one another (into defined panels) by laterally extending plication or fold regions in the body. In one embodiment, top  130 , bottom  140 , first side  150 , and second side  160  are a single unit of connected panels folded at plications (e.g., weak areas of the thermoformed plastic) to form a rectangular (e.g., square) body structure. FIG. 1 shows separately formed door  110  and rear  120  connected to the body structure. Representatively, door  110  is connected to first side  150  and second side  160  by mating latch components. Representatively, FIG. 1 shows protruding latch components  115  each extending from top  110  with an interiorly protruding edge or shelf (not shown) to mate with latch components on second side  160 . Representatively, the latch components of first side  150  and second side  160  include opposing protruding edges or shelves. Representatively, a protruding edge or shelf of an edge latch component  115  is extended by force over an opposing edge of a latch component on second side  160  (not shown). The connection of rear  120  to first side  150  and second side  160  may be similar. In another embodiment, rear  120  is connected by a friction “snap” type fit. In alternative embodiments, door  110  and/or rear  120  may be sized to fit into place over or within first side  150  and second side  160 , respectively, so that door  110  and rear  120  may be connected to first side  150  and second side  160  by mating, friction or with an adhesive.  
         [0022]    In one embodiment, FOSB  100  is designed to be compatible with an IC tool load-port or a nest for common machine interface of wafers from a FOSB. FOSB  100  may also be compatible with handling vehicles, such as automated guided vehicles (AGVs) or overhead vehicles (OHVs). An exterior surface of base  140  of FOSB includes, but may not be limited to, carrier sensing pads  175  and V blocks  170  positioned, in one embodiment, according to one industry standard (e.g., SEMI M31-0999) to mate with a kinematic coupling. Representatively, in compliance with SEMI M31-0999, V blocks  170  have a height dimension that extends from the plane defined by the exterior surface of base  140  (e.g., approximately two millimeters (2 mm) above the plane). Base  140  also includes info pads (info pads  180 A,  180 B,  180 C, and  180 D). According to SEMI M31-0999, the info pads may communicate information about FOSB  100  to an IC manufacturing tool. For example, info pad  180 C representatively may indicate the capacity of FOSB  100  (e.g., the number of wafers inside) by a distance info pad  180 C extends from a surface of base  140 . In addition to info pads, FOSB  100  may include a location for a radio frequency (RF) pill to be placed, such as on rear  120 , that may contain information about FOSB  100 . It is appreciated that an RF pill may be placed anywhere on the FOSB.  
         [0023]    Referring to FIG. 1, base  140  of FOSB  100  may optionally include, in one embodiment, areas  190  designated as conveyor rails extending longitudinally on opposing sides of the exterior surface of base  140 . Areas  190  may act as rails for conveyors or forklifts. Base  140  may also include a number of stiffening features  185 , typically depressions or dimples formed by molding in the exterior surface. Stiffening features may also optionally be included on other panels.  
         [0024]    [0024]FIG. 1 shows second side  160  including handles  165  to allow FOSB  100  to be carried/loaded. The handles, in one embodiment, are optional and are formed, for example, by molding into second side  160  (e.g., through depressions or protrusions). Similar handles may be located/formed in first side  150 . In another embodiment, handles may be located vertically on first side  150  and second side  160 . Representatively, handles may be tucked up and under at a position where door  110  connects to first side  150  and/or second side  160 . First side  150  and second side  160  may each also include one or more latch components for connecting door  110  thereto (e.g., through latch component  115 ).  
         [0025]    [0025]FIG. 2 shows the FOSB of FIG. 1 from another angle. In this embodiment, FOSB  100  is rotated forward and clockwise so that door  110  faces forward on the page. Door  110  has been removed to expose an interior of FOSB  100 . From this view, an interior side of door  110 , rear  120 , and first side  150  are visible. FIG. 2 also shows wafer  270  positioned within an interior of FOSB  100  covering from view an interior side of base  140 .  
         [0026]    In one embodiment, the interior of FOSB  100  includes components for supporting wafers, for example, up to 25 300 mm wafers according to one current standard (e.g., SEMI M31-0999). In other embodiments, the capacity of FOSB  100  may be modified to support more or less than 25 wafers or to support wafers of different size. Referring to FIG. 2, an interior of FOSB  100  includes 25 laterally extending shelves on each of first side  150  (shelves  250 ) and second side  160  (shelves  260 ). The shelves are formed (e.g., by molding) into the body of the individual components, for example, in a thermoform or blow molding process. Shelf portions are also formed on an interior side of door  110  (shelf portions  210  and  212 ) and rear  120  (shelf portions  220  and  222 ) by a similar process. Alternatively, the shelves and shelf portions may be formed as inserts that are connected (e.g., by adhesive or fastener) to an interior side of first side  150 , second side  160 , door  110  and rear  120 , respectively. In the embodiment shown in FIG. 2, shelf portions  210  and  212  of door  110  are separated by a longitudinally extending window of, for example, a transparent plastic material. Similarly, shelf portions  220  and  222  of rear  120  are separated by longitudinally extending window  225  of, for example, a transparent plastic material. The windows are optional.  
         [0027]    The magnified portion of an interior of first side  150  shows further details of shelves  250 . It is appreciated that, in one embodiment, shelves on second side  160  of FOSB  100  are similarly configured. Specifically, the inset shows three shelves  251 ,  252  and  253 . Each shelf extends interiorly from a plane defining an interior surface of first side  150  to provide sufficient surface area (in conjunction with other shelves/shelf portions) to support a wafer.  
         [0028]    [0028]FIG. 3 shows a cross-section through line A-A′ of FIG. 2. Referring to FIG. 3, shelves  251 ,  252 , and  253  are shown. According to SEMI M31-0999, representative pitch, H 1 , between adjacent shelves (e.g., shelf  251  and shelf  252 ) is on order of 10 millimeters for a FOSB capable of holding 25 300 mm wafers. A representative distance, H 2 , between a superior surface of a shelf and an inferior surface of a superior shelf is on the order of six millimeters or more. A typical 300 mm wafer has a thickness on the order of 0.775 mm±0.025.  
         [0029]    [0029]FIG. 4 shows a cross-section through line B-B′ of FIG. 2. From this view, an interior of first side  150 , second side  160  and rear  120  are illustrated. First side  150  includes shelf  251 . FIG. 5 illustrates a side view of shelf  251 . Second side  160  includes shelf  451 . Rear  120  may include shelf portions  421  and  422  separated, for example, by a longitudinally extending window (not shown). When assembled, a portion of shelf  251  (first side  150 ), shelf  451  (second side  160 ), shelf portion  421  (rear  120 ), and shelf portion  422  (rear portion  120 ) lie in a similar plane. Collectively, when assembled, the shelves and shelf portions extend interiorly from the individual FOSB portions (first side  150 , second side  160 , and rear  120 ) to provide support for a wafer placed in FOSB  100 .  
         [0030]    Referring to shelf  251  and FIG. 4 and FIG. 5, in one embodiment, complying with SEMI M31-0999, shelf  251  includes first portion  460  having a thickness, T 1 . Shelf  251  also includes portion  465  having a thickness, T 2 , that is less than T 1 . Portion  465  is, for example, an indentation or recess in a superior surface of shelf  251 . A wafer, such as wafer  470  (illustrated in ghost lines) is intended to be seated in second portion  465  when wafer  470  is completely within an interior of FOSB  100 . In this manner, junction  455  between first portion  460  and second portion  465  acts as a support stop, a front support stop, for wafer  470  in FOSB  100 . The front support stop or pitch protection reduces the ability of a wafer to inadvertently slide out of the front door.  
         [0031]    Shelf  251  of first side  150  has been described in detail. Shelf  451  of second side  160  is, in one embodiment, arranged similarly although a mirror image of shelf  251 . Shelf portion  421  and shelf portion  422  of rear  120  include a horizontal portion in a plane similar to a horizontal surface of second portion  465  of shelf  251  relative to a datum through the top and bottom of FOSB  100 . A collective shelf of first portion  465  (shelf  251 ), a similar portion of shelf  451  of second side  160  and shelf portion  421  and shelf portion  422  of rear  120  may be in compliance with an industry standard for a FOSB. Representatively, a collective shelf has, in one embodiment, an interior radius, R 1 , of approximately 150 mm or less and an exterior radius, R 2 , of approximately 152 mm or more. In this manner, a 300 mm wafer will be supported by the collective shelf.  
         [0032]    Referring again to FIG. 2, in one embodiment, top  130  of FOSB  100  includes optional automation handling flange  235  that may be positioned, through a frictional slide-in fit or other coupling method, to extend superiorly (as viewed) from a plane defined by an exterior surface of top  130 . According to SEMI M31-0999, automation handling flange  235  allows for manipulating FOSB  100 . Representatively, automation handling flange  235  may extend approximately at least 15 mm above an exterior surface of top  130  when deployed for automated handling.  
         [0033]    Top  130  of FOSB  100  also includes filter opening  240  for an optional filter. A filter may be inserted around filter opening  240 , for example, to regulate an environmental pressure equalization of FOSB  100 .  
         [0034]    An additional, optional feature incorporated into FOSB  100  is indicator  245 . Indicator  245  may be a manual or electronic indication of, for example, how many times FOSB  100  has been used to transport wafers. A representative manual indication for indicator  245  is, for example, depressible dimples. A depressed dimple may indicate one use. Two depressed dimples, two uses. An electronic indication for indicator  245  is, for example, a light emitting diode or radio frequency device that may be tripped, for example, after each use.  
         [0035]    An alternative indication for optional indicator  245  of FOSB  100  is an indication of a level of shock that FOSB  100  may have experienced. For example, indicator  245  may include a switch that is triggered (either manually or electronically) when FOSB  100  is subjected to a particular level of stress or shock. Representatively, a weighted switch or a motion-sensitive switch may actuate upon a certain stress or shock (a predetermined magnitude) received by FOSB  100 . The switch would then indicate that FOSB  100  may not be suitable for further use.  
         [0036]    [0036]FIG. 6 shows components of the body of FOSB  100  (excluding door  110  and rear  120 ), disposed in a linear arrangement. As noted above, the body parts of FOSB  100  consisting of top  130 , bottom  140 , first side  150 , and second side  160  may be formed as a single unitary body of, for example, thermoformed or blow-molded, multiple sheet (e.g., twin-sheet polymer or plastic). The individual sections of the body are distinguished from one another by folds or plications representing, for example, weakened portions of a twin-sheet body. In this manner, the individual components are hingedly joined by way of the plications or folds. FIG. 6 shows plication  610  between first side  150  and bottom  140 ; second plication  620  between bottom  140  and second side  160 ; and third plication  630  between second side  160  and top  130 . Each plication (plication  610 , plication  620 , and plication  630 ) extends laterally as a commissure or line of union or junction between two components of the body of FOSB  100 . The plications allow the components of the body to be plicated or folded at respective plications into a rectangular unit. When the body is folded into a rectangular shape, first side  150  may be connected to top  130  through a mating hatch.  
         [0037]    [0037]FIG. 6 shows interior portions of top  130 , bottom  140 , first side  150  and second side  160 . In terms of a twin-sheet thermoformed body, FIG. 6 shows one embodiment of a molding of a first of two sheets. From this view, shelves  250  of first side  150  and shelves  260  of second side  160  are illustrated. Also illustrated are representative stiffening features  640  on top  130  and stiffening features  650  on bottom  140 .  
         [0038]    [0038]FIG. 7 shows a second side of body components of FOSB  100  (e.g., an exterior side). FIG. 7 shows, for example, the molding of a second sheet of a twin-sheet thermoformed body component for FOSB  100 . Illustrated in FIG. 7 are first plication  610 , second plication  620 , and third plication  630 .  
         [0039]    [0039]FIG. 8 shows an exploded view of components of FOSB  100 . FIG. 8 shows the body of FOSB  100  folded at plications  610 ,  620 , and  630  into a rectangular structure consisting of top  130 , bottom  140 , first side  150  and second side  160 . In one embodiment, lateral extending gasket  830  is inserted at a commissure or line of junction between top  130  and first side  150 . Top  130  may be connected to first side  150  by L-shaped mating folds of top  130  and first side  150 , respectively. The mating interlock of these folds may be fastened together with, for example, riveting-type, “Christmas tree” fasteners  835 . FIG. 8 also shows laterally extending gasket  840  at plication  610 ; laterally extending gasket  850  at plication  620 ; and laterally extending gasket  860  at plication  630 . FIG. 8 also shows rectangular gasket  810  and rectangular gasket  820  positioned between door  110  and rear  120  and the other body components of FOSB  100 , respectively.  
         [0040]    [0040]FIG. 9 illustrates a flow chart of a representative process for forming thermoformed components suitable for use in constructing a FOSB. A twin sheet thermoform process is described. A material for a FOSB may be a plastic material such as, but not limited to, a polycarbonate, polyethylene (e.g., high density polyethylene (HDPE)), polypropylene, acrylic (acrylate), glycol-modified polyethylene terephthalate, alkyl benzene sulfonate, and various mixtures of one or more of the noted polymers or others. A suitable material may further include fillers, such as talc. One composition is, for example, 75 percent HDPE and 25 percent filler (e.g., talc) co-extruded into pellets. The pellets may be used to form a first sheet and a second sheet of polymer or plastic material, by, for example, extrusion techniques.  
         [0041]    In one embodiment, the first sheet of plastic is preheated to a suitable temperature to soften the material to allow molding (block  910 ). Representatively, a temperature is sufficient to allow manipulating of the sheet into a shape of a mold to which the sheet is brought into contact. It is appreciated that the particular polymer material selected will contribute to a selection of an approriate preheat temperature (e.g., a melting point of a polymer). The first sheet is then introduced into a first mold (block  920 ). Representatively, the first mold may include the appropriate shapes for an interior of body components of FOSB  100 . FIG. 6 is a representation of a shape (shapes) that may be desired to be achieved from a single mold (e.g., four panels of FOSB  100 ). Once the first sheet is placed into a first mold, a force is applied to the first sheet to give shape to the first sheet of plastic consistent with the mold (block  930 ). One suitable force is a vacuum force.  
         [0042]    Concurrently with or subsequent to a molding of a first sheet of plastic, a second sheet of polymer or plastic material may be preheated (block  940 ). The second sheet of plastic is introduced into a second mold (block  950 ). Representatively, where the first sheet and first mold formed a sheet of plastic similar to the shape illustrated in FIG. 6, the second mold may form the shape illustrated in FIG. 7 (e.g., the exterior of FOSB  100 ). To give shape to the second sheet of plastic, a force, such as a vacuum force, is applied to the second sheet in the second mold (block  960 ). Once a desired shape has been given to the first sheet and the second sheet, the first sheet and second sheet are joined, such as thermally and/or pressure joined at their ends and planarly, to yield a thermoformed twin-sheet structure (block  970 ). It is appreciated that each component of, for example, FOSB  100  (each body component) may be formed as a multiple-sheet thermoformed structure. Alternatively, one or more components may be formed as a multiple-sheet thermoformed structure or other plastic structure. For example, windows in a door and/or rear of the structure, in one embodiment, are triple sheet structures.  
         [0043]    In the embodiment described above with respect to FIGS.  1 - 8 , body portions of the FOSB including of top  130 , bottom  140 , first side  150 , and second side  160  were formed as a single unit or body distinguished by plications that allowed folding or hinging of the individual body components or panels. FIGS. 10 and 11 illustrate another embodiment of a suitable, possibly multiple sheet (e.g., twin-sheet) thermoformed or blow molded structure. FOSB  1000  includes, in this embodiment, five panels as a unitary body including, rear  1020 , top  1030 , bottom  1040 , first side  1050 , and second side  1060 . Rear  120 , in this embodiment, is directly connected to each of top  1030 , bottom  1040 , first side  1050 , and second side  1060 . The individual components or panels are hingedly connected to one another through plications or folds as described above with respect to FOSB  100 . FIG. 10 shows an interior side view of the structure. FIG. 11 illustrates FOSB  1000  being folded at plications or folds into a rectangular structure.  
         [0044]    In addition to the above embodiments where an FOSB is formed by assembling panels at folds or plications, other embodiments are also contemplated. For example, multiple panels (e.g., side portions and top and bottom portions and possibly rear portion) may be formed from a single mold without plications. In this manner, each shelf or wafer support could be a continuous structure about the interior of the FOSB. Alternatively, the panels may be formed as distinct units (from distinct molds) and assembled together by fasteners, friction fit or adhesive.  
         [0045]    A FOSB of thermoformed or blow-molded components/panels offer shock resistance to components (e.g., wafers) contained therein. A multiple sheet structure, provides an improved measure of shock resistance over single sheet structures.  
         [0046]    A FOSB such as described above with respect to FIGS.  1 - 8  and the accompanying text, may also be compatible, in one embodiment, with a shipping-box front opening mechanical interface that itself is compatible with the port that conforms to an industry standard for automated doors (e.g., SEMI E62-0302A, “Provisional Specification for 300 mm Front-Opening Interface Mechanical Standard (FIMS),” Sep. 18, 2001). FIG. 12 shows an illustration of an automated door suitable for use with FOSB  100 . In this context, FOSB  100  might be shipped to an IC manufacturing facility with door  110 . At the manufacturing facility, door  110  could be removed and replaced with an automated door. FIG. 12 shows FOSB  100  including rear  120 , top  130 , bottom  140 , first side  150 , and second side  160 . Door  110  has been removed exposing an interior of FOSB  100 . FIG. 12 also shows automated door  1200 .  
         [0047]    Door  1200 , in one embodiment, is designed to fit on an inner rim/opening ledge of FOSB  100  (e.g., on an inner door frame defined by top  130 , bottom  140 , first side  150 , and second side  160 ). Door  1200  is used in place of a manual door (e.g., door  110 ). Such doors are used, for example, in order for the FOSB to be handled as a wafer carrier on machine centers. Such machines engage the FOSB and open them through the automated doors in a handling operation.  
         [0048]    A typical automated door, such as door  1200 , is formed of injection molded plastic. Door  1200  includes one to two turning cams  1210  that are engaged by a keyway that the machine interfaces. Keys from a machine slide into cam keyways  1220  and turn cams  1210 . Cams  1210  actuate plastic arms or tabs  1230  that extend/retract into recessed pocket features  1240  in the door frame defined by top  130 , bottom  140 , first side  150 , and second side  160  (e.g., 2-3 mms recessed slots).  
         [0049]    When an automated door is inserted on FOSB  100 , cams  1210  are oriented so that the machine keys can be inserted or withdrawn. In this position, tabs  1230  are in pockets  1240  and door  1200  is seated in the door frame. Door tabs may engage FOSB  100  on horizontal sides (e.g., first side  150  and second side  160 ) of the door frame in two positions (e.g., one on each side), or on the top and bottom (e.g., top  130  and bottom  140 ) of the door frame surfaces at four locations (e.g., left and right (top and bottom)) as shown.  
         [0050]    To remove an automated door, a machine inserts keys into keyways  1220 . The machine turns the keys approximately 90 degrees which in turn withdraws tabs  1230  into the internal of door  1200 . The keys on the machine are now engaged into cams  1210  and the machine can pull the door of FOSB  100 . The machine removes the door out of the way and FOSB  100  will be engaged on a load port and the wafers accessed.  
         [0051]    In addition to other features, an interior side of door  1200  may include wafer engaging features to retain (e.g., lightly catch/hold) wafers for mild protection during handling when door  1200  is used on FOSB  100 . An exterior side of door  1200  may further include handles to allow manual actuation of cams  1210  that, in turn, activate tabs  1230 . In addition, handles may enable holding of door  1200 . An exterior side of door  1200  may also include holes for registration pins and door presence sensing areas.  
         [0052]    In the preceding detailed description, reference has been made to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.