Embodiments of the present invention relate to a transportation fixture and package to transport a substrate rack.
A substrate rack can be used to hold a batch of substrates during fabrication of the substrates to form display panels and semiconductors. For example, a substrate rack, such as a wafer processing boat, has a series of vertically positioned slots that can each hold a semiconductor wafer. An exemplary substrate rack 10 that can hold semiconductor wafers in a deposition chamber is illustrated in
In use, after several process cycles, the rack 10 is cleaned or reconditioned to remove accumulated process deposits. For example, in a typical CVD process, the CVD material deposited on the substrate also deposits on the substrate rack 10. After a number of CVD process cycles, a layer of CVD material builds up on the substrate rack 10. This built up layer of deposits can contaminate the CVD chamber and the substrates if the deposits flake off the substrate rack. Accordingly, the deposited materials are periodically removed from the substrate rack 10 to recondition and clean the substrate rack for use in further process cycles.
Typically, the substrate rack is packaged and shipped to an off-site cleaning facility for cleaning or reconditioning of the rack 10. However, there are several problems with transportation of the rack 10. First, the assembled substrate rack is heavy often weighing between about 50 to 100 pounds and yet fragile which makes it difficult to ship without breakage. Also, the rack 10 is sensitive to the ambient environment and can erode or corrode when exposed to air. Also, the deposits formed on the rack 10 can be toxic or hazardous to handlers. Thus, prior to being shipped to the cleaning site, a thin sealing layer, typically comprising non-doped silicon, is deposited on the substrate rack 10 to protect handlers from exposure to the deposits on the rack. The substrate rack 10 is then wrapped in air-cushioned “bubble-wrap” and placed into a wooden crate for shipping. Because the substrate rack 10 is extremely fragile, it must be transported in one position, i.e., with its longitudinal axis in the vertical direction; otherwise, the brittle components of the substrate rack can chip or break. All of these solutions to the transportation problem add to the cost of cleaning and reconditioning the rack 10.
In transit to the cleaning site, the crate containing the substrate rack 10 may be subjected to inspection by immigration or law enforcement officers. To perform the inspection, the officer typically opens the crate and removes the bubble-wrap to ensure that contraband is not contained in the crate. After inspection, the substrate rack 10 is re-packaged and transported to the cleaning site. There, the substrate rack is placed in an acid bath for a few hours to remove the layer of deposited materials. Up to this time, the substrate rack 10 is assembled because the layer of deposited materials glues the components of the substrate rack together, and the substrate rack cannot be disassembled without damaging the components. After the first acid bath, the layer is removed and the components of the substrate rack become “unglued.” The substrate rack 10 is then disassembled, cleaned again, and baked dried at approximately 400° C. for about ten (10) hours. Once dried, the disassembled reconditioned components are packaged and shipped back to the customer site, where the substrate rack 10 is reassembled and ready for use.
During the above-described transportation and reconditioning process, a large percentage of substrate racks 10 are irreparably damaged. For example, when the substrate rack 10 is packaged, i.e., wrapped in bubble-wrap and placed in the crate, unpacked, or repackaged, e.g., at the customer site, during inspection and at the cleaning site, the silicon carbide coat on the components of the substrate rack 10 can be easily chipped or broken, rendering the components useless. If the crate is tilted or dropped during transport, the fragile components can break or chip. The substrate rack 10 can be damaged at the customer site when it is being reassembled by lab technicians who are typically inexperienced and unskilled in reassembling the substrate rack. In addition to damaging the substrate rack, handlers and/or inspection officers can be exposed to toxic materials beneath the thin sealing layer when the components are broken or chipped.
Thus, it is desirable to be able to efficiently transport a substrate rack 10 from a clean room to a cleaning or off-site facility for cleaning or reconditioning. It is also desirable to minimize breakage of the substrate rack 10 during the packing, unpacking, and transportation processes. It is further desirable to efficiently clean the rack 10 without damaging the components. It is further desirable to protect handlers from exposure to the deposits on the rack during handling and transportation.
A transportation fixture for holding a substrate rack comprises top and bottom endplates. A plurality of posts attach the top endplate to the bottom endplate and are spaced apart a sufficient distance to confine the substrate rack therebetween. Each post has a longitudinal inside edge. A compliant bumper is coupled to each longitudinal inside edge of the posts. The transportation fixture cushions, secures and protects the substrate rack during transportation.
In another embodiment, the transportation fixture comprises top and bottom endplates that are triangular and have apexes. Three posts attach the apexes of the top endplate to the apexes of the bottom endplate. A compliant bumper is coupled to each post.
A shell having at least a portion which is light permeable, can also enclose the fixture to protect the substrate rack from the external environment while still allowing viewing of the fixture and rack without opening the shell. In one version, the shell comprises a first tray having a closed end and an open end with a first circumferential lip, at least a portion of the first tray comprising a light permeable material. A second tray comprises a closed end and an open end with a second circumferential lip, at least a portion of the second tray comprising a light permeable material. The first and second circumferential lips mate so that the open ends of the first and second trays face each other to form a cavity therebetween. A sealing gasket can be used between the circumferential lips to form a seal. The shell can also include exhaust port and purge gas couplings for evacuating the shell and filling the shell with a non-reactive gas, respectively. The shell allows customs or other visual inspections of the fixture and rack that would otherwise require opening the shell to view its internal contents.
A transportation casing can also be used to enclose the shell for shipping. The transportation casing comprises a rigid box having an interior foam block that is contoured to match the shape of the shell. The casing provides additional mechanical protection during transportation.
These features, aspects and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings, which illustrate examples of the invention. However, it is to be understood that each of the features can be used in the invention in general, not merely in the context of the particular drawings, and the invention includes any combination of these features, where:
A transportation package comprising a transportation fixture can be used to transport a substrate rack 10, as shown in
An exemplary transportation fixture 200 for holding the substrate rack 10 is illustrated in
In one version, the bottom endplate 210b includes a skid plate 230 that prevents the substrate rack 10 from slipping off of the fixture 200 during the loading and unloading process. The endplates 210a, 210b can also have raised bumps (not shown), shaped as ribs, islands, mesas or ridges, that are located on the surface 232 facing the stack 10 to prevent contact between the substrate rack 10 and the endplates 210a, 210b, when the rack 10 has protruding end portions (also not shown). The raised bumps also assist in maintaining the rack 10 in a vertical position while the substrate rack 10 is loaded and unloaded. The raised bumps can be either coupled to, or integrally formed on, the surface of the endplates 210a, 210b.
Each endplate 210a, 210b can include reinforcing structures 240, such as blocks, brackets or gussets, to increase the rigidity of the endplate 210a, 210b and to provide other functions, such as a means for lifting and holding the transportation fixture 200. For example, the reinforcing structures 240 can include holes 243 that can serve as finger-holds or means for attaching grips or other carrying straps. Like the raised portions 230, the reinforcing structures 240 can be either coupled to, or integrally formed on, the endplates 210a, 210b. Moreover, the endplates 210a, 210b can provide openings 250 to facilitate the flow of a cleaning solution, i.e., acid, over the substrate rack 10 components.
The posts 220a-c coupling the endplates 210a, 210b are positioned such that the substrate rack 10 is securely held between the posts 220a-c, as is shown in
Referring to
As shown, in this version, each of the posts 220a, 220b, 220c are made from a pair of joined strips 222a,b 222c,d and 222e,f respectively. The strips 222a,c,e each have an inside surface 224a,c,e that contacts an inside surface 224b,d,f of the other strips 222b,d,f. Each strip 222a-f also has a longitudinal groove 226a-f along the inside edge 228a-f respectively. When the longitudinal grooves 226a-f are aligned with one another, they join to form an internal channel into which a reinforcing rod 232 can be positioned. In one version, the reinforcing rod 232 strengthens the post 220 and can be a stainless steel rod. Because the reinforcing rod 232 is at least partially enclosed by the channel, it is protected from the corrosive solutions used during the reconditioning process. To ensure this protection, the strips 222 can be joined together by a conventional inert, heat-resistant sealant, such as a ceramic or epoxy sealant.
As is shown, each strip 222 has an inside longitudinal edge 228a-f that faces the interior of the fixture 200, i.e., toward the substrate rack 10. The longitudinal edges 228 can be narrow (as shown) or wide (not shown). In one version, the longitudinal edge 228a-f is receives a compliant bumper 234a-c along the joined longitudinal edges 222b. By cupping the inside longitudinal edges 228 the compliant bumpers 234 are securely attached. In one version, the bumper 234 can be attached via stainless steel screws that are sealed with a high temperature silicone sealant. Thus, servicing and replacement of the bumper 234 is simplified. In another version, the longitudinal edges 228 can be substantially straight and the compliant bumpers 234 attached to the longitudinal edges 228 by a chemically inert, heat-resistant adhesive. In one version, the compliant bumpers 234 can be a polymer tubing, such as low durometer rubber that is sealed at its open ends, an elastomer strip, or a strip made from another compliant non-absorbent chemically inert material. In another version, the bumpers 234 can include ridges or other texture to secure the disks 20. In another version, the bumpers 234 can be pneumatic bladders that hold and cushion the substrate rack 10. The fixture 200 with the posts 220 and compliant bumpers 234 secure, protect and cushion the substrate rack 10, in particular, the graphite disks 20. Once the substrate rack 10 is securely loaded into the transportation fixture 200, the compliant bumpers 234a-c on the posts 220a-c allow the substrate rack 10 to be placed in any position, e.g., horizontally, without damaging its components.
Referring to
In one version, the pin 244 serves as a hinge such that if the pin 244 connecting one end of the post 220 to one endplate, e.g., the bottom endplate 210b, is removed, the post 220 can rotate about the pin 244 connecting the other end of the post 220 to the top endplate 210a. This opens up and allows easy access to the interior of the transportation fixture 200. One or both ends of the post 220 can be hinged in this manner. In addition, one or more posts 220 can be hinged, while others are fixedly attached to the endplates 210a, 210b.
The substrate rack 10 can be placed in the transportation fixture 200 directly from the deposition chamber because the transportation fixture 200 is preferably made from a non-metallic, chemically inert and clean material. To facilitize this, one of the endplates, e.g., the top endplate 210a can be removed completely simply by removing the pins 244 attaching the posts 220 to the top endplate 210a and by rotating the posts 220 outward to allow the substrate rack 10 to be lowered onto the bottom endplate 210b of the transportation fixture 200. Then, the posts 220 can be closed and reattached to the top endplate 210a.
In another version of the transportation fixture 200, the endplates 210a, 210b are shaped as a top support frame 710a at the top of the rack 10 and a bottom support frame 710b at the bottom of the substrate rack 10, respectively, as shown in
The transportation fixture 200 provides rigid support such that the substrate rack 10 is not subjected to torsional or normal forces that can cause breakage when the stack 10 is transported to and from a reconditioning facility. Moreover, because the transportation fixture 200 is made from chemically-inert, non-metallic, and heat-resistant material, the transportation fixture 200 can be placed in the cleaning solution along with the substrate rack 10 and baked at high temperatures without damaging itself, the substrate rack 10, the acid bath, or the oven. Accordingly, the transportation fixture 200 can be used to protect the substrate rack 10 during the reconditioning process until the substrate rack 10 is ready to be disassembled. Further, after the components of the substrate rack 10 have been thoroughly cleaned dried, and reassembled by skilled technicians, the transportation fixture 200 can be reused to transport the fully reconditioned and assembled substrate rack 10 back to the customer. Because the substrate rack 10 is returned assembled, the likelihood of a lab worker breaking the substrate rack 10 while attempting to reassemble the components is reduced.
In one version, the transportation fixture 200 is placed in a shell 800 to form a transportation package 802 that further protect the transportation fixture 200 and the substrate rack 10 during transit. In one embodiment, as shown in
The assembled pair of trays 850, 860 serve as a self-standing receptacle that encloses the fixture 200 and substrate rack 10, and can even have built-in handles (not shown) to transport the fixture 200 directly into a reconditioning environment or into a clean room. The assembled pair of trays 850, 860 can also be stored for a period of time in the clean room in a sealed and stable environment, and opened only when the substrate rack 10 is needed for immediate use in the process chamber, thereby further reducing any contamination of the substrate rack 10 in the trays 850, 860.
The trays 850, 860 can comprise a continuous circumferential lip 852a,b that runs around the peripheral circumference of the trays 850, 860. A sealing gasket (not shown) can be placed between the tray lips 852a,b to provide a tight seal between the assembled trays 850, 860 such that the substrate rack 10 and transportation fixture 200 are protected from contaminants. The circumferential lips 852a,b reduce the length of gas tight seal needed to seal off the two trays 850, 860. Also, the circumferential lips 852a,b allow the shell to be positioned vertically when lifting off the top tray 850 to provide access the transportation fixture 200 and rack 10 in the shell 800a. This version is advantageous when the fixture 200 and rack 10 need to be maintained in a vertical orientation when being placed into or removed from the shell.
Preferably, at least a portion of the shell 800a is made from a rigid material that is also light permeable to allow visual inspection of the substrate rack 10 that is held inside. As used in this description, light permeable refers to a material that allows at least some wavelengths of light to pass through the material, such as for example, a transparent, translucent, cloudy or partially opaque material. For example, a suitably light permeable material can have a visible light transmission percentage of at least about 20%. The shell 800a can also be surface polished to enhance the clarity of transmitted light and views. The shell 800a can also be made entirely from the light permeable material or only a portion of the shell can be made from the light permeable material, such as a window. An inspector should be able to visually examine the internal contents of the bins without breaking open the seals. For example, in one version, only one or more of the trays 850, 860 is made from the light permeable material, however, the entirety of both trays 850, 860 can also be made from the light permeable material. Moreover, the shell 800a can include markings that indicate the nature of the contents and potential hazards associated with opening with shell 800a. Such indicia can be provided on the interior surface of the light permeable material of the shell 800a.
A suitable light permeable rigid material is a heat setting thermoplastic polymer, such as a high density polyethylene, for example polymers that are based on polyethylene terephthalate (PET), glycol-modified PET (PETG), oriented PET (O-PET), or polyethylene naphthalate (PEN), or blends thereof with each other or with other resins. Preferably, the light permeable rigid material is a moldable thermoplastic that softens when heated to form to a mold shape, such as polyethylene terephthalate glycol (PETG), such as PAL-G sheet fabricated by Palram, Ramat Yohanan, Israel. The trays 850, 860 can be molded as a single integral piece using conventional plastic molding techniques from a single blank sheet of thermoplastic material. The blank sheet can be thermoformed into heat-set, thin walled trays utilizing conventional thermoforming methods and equipment such as vacuum assist, air assist, mechanical plug assist or matched mold. A single mold can also be used to make the trays, and portions of the molded trays can be cut off and the cut trays assembled to form a shell having three or more different sections, as shown in
Advantageously, the shell 800a allows visual examination of its internal contents without opening the shell or breaking its seal. If the substrate rack 10 is broken or chipped, the breakage can be immediately discovered without opening the shell 800a in an intermediary transportation point, such as a parts distribution warehouse. It is desirable to inspect the state of the transportation package 802 having the enclosed packaged stack 10 prior to shipment without opening and contaminating the contents of the shell. The shell 800a also allows customs officers to verify internal contents in accordance with newer, more stringent customs inspections during international transportation across borders, without breaking the seal in a potentially adverse environment, which may cause the stack 10 to be subsequently scrapped upon completing the voyage. The shell 800a also allows the fragile substrate rack 10 to be safely transported from the clean room to the reconditioning facility and vice versa, while maintaining a good gas tight seal from the external environment.
The transportation package 802 can also include a hard casing 870 which is used to enclose the shell 800a (or any of the other shell versions described herein) for shipping, as for example, shown in
Typically, the casing 870 is opened outside the clean room, and the shell 800a containing the transportation fixture 200 with the enclosed stack 10 removed from the casing 870, cleaned if needed, and then carried into the clean room. Because the gases trapped in the pores of the foam block 876 can outgas into the clean room environment; and the bonding layers between the blocks of foam that are used to create the three-dimensional matrix can also outgas or create polymeric contaminant particles, the transportation package is not brought into the clean room.
The box 874 typically comprising a top wall 877, sidewalls 878, and a bottom wall 879, which are all made of rigid material, such as a plastic or metal sheet. Suitable rigid plastics comprise a casing made of molded polypropylene, as for example made by Hardigg Indus., South Deerfield, Mass. The walls 878, 879, 881 of the box 874 can also be reinforced with metal edging 883, for example aluminum edging. The box 874 can also have handles 880 and wheels 882 to facilitate transportation of the packed components from the shipping vehicle to the clean room of a wafer fabrication facility or the refurbishment facility, as shown n
Other versions of the shell 800 will now be described. In one version, a shell 800b comprises lips 852a,b which have troughs that extend parallel to the longitudinal and transverse axes of, as shown in
Referring to
Yet another version of the shell 800d, shown in FIGS. 9 to 11, also comprises three trays 952, 954 and 956, but which are joined together in a different manner. Referring to
In another version, the shell can also have a recessed cup 974 to house the exhaust port coupling 966 as shown in
An exhaust port coupling 966 is located on the top wall 967 of the top tray 952. The exhaust port coupling 966 is large enough to allow insertion of a conventional Draeger gas sampling tube, which can be used to screen the gases in the shell, for example, to detect toxic gases. However, it should also not be too large otherwise it will protrude too far from the top wall 967.
A purge gas coupling 980 is located on the sidewall 982 of the bottom tray 956. The purge gas coupling 980 allows a purge gas to be admitted into the shell from an outside purge gas source (not shown). A typical purge gas includes a non-reactive gas, such as nitrogen or argon, and serves to provide an inert or non-reactive environment in the shell 200 to protect the rack 10 from exposure to the external environment.
The present invention has been described with reference to certain preferred versions thereof; however, other versions are possible. For example, the transportation package 802 and transportation fixture 200 can be used in other types of applications, as would be apparent to one of ordinary skill, for example, to transport other fragile processing components. Other configurations of the transportation fixture 200 can also be used to accommodate the shape and size of a processing component. For example, the shape of the endplates 210a, 210b can be shapes other than that triangular or frames, for example, square, hexagonal or even round plates or frames. The shell 800 can be also made from other materials or have a small window of transparent material surrounded by opaque material. The casing 870 can also have other shapes, for example, cylindrical and can be built of steel or other metals. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained herein.