Wafer carrier with scavenging device

Abstract

A wafer carrier includes a wafer carrier housing having an interior space and a scavenging device with a scavenging compound in fluid communication with the interior space. The wafer carrier can be used as a microenvironment for semiconductor wafers enclosed within the carrier as they move through fabrication process steps.

Description

WAFER CARRIER WITH SCAVENGING DEVICECLAIM OF PRIORITY

[0001] This application claims priority from U.S. Provisional Patent Application Serial Nos. 63 / 448,835 bearing Attorney Docket Number 1202302-US-F and filed on February 28, 2023; 63 / 448,843 bearing Attorney Docket Number 1202303-US-F and filed on February 28, 2023; and 63 / 596,452 bearing Attorney Docket Number 1202323 -US-F and filed on November 6, 2023; each of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present disclosure relates generally to wafer carriers, and, more particularly, to wafer carriers for enclosing semiconductor wafers within a microenvironment with oxygen and / or moisture scavenging as they move through one or more fabrication process steps.BACKGROUND

[0003] As semiconductor fabrication technology advances, with continuous miniaturization of devices, there are more stringent requirements in the fabrication environment and, in particular, in minimizing contamination of semiconductors.

[0004] The negative effect of moisture and oxygen on semiconductor wafers is usually a function of two parameters: contaminate concentration and exposure time. Existing solutions to the problem may focus on reducing exposure time. Alternatively, if this is uneconomical or not technically possible, steps may be taken to reduce contaminate concentration levels in any environment to which wafers are exposed. Such reduction is usually achieved by purging an environment containing wafers with extremely clean dry air or a pure inert gas, such as nitrogen.

[0005] Sealed containers, such as FOUPs (front opening unified pods), FOSBs (front opening shipping boxes) or SMIF (standard mechanical interface) pods may be used as wafer containers or reticle pods. Means may be provided for flushing the interior volume of such containers which contain the wafers in use, with nitrogen, to address and / or solve the contamination problem.

[0006] However, such flushing processes are less able to meet the technical requirements as technology advances and, therefore, the problem of maintaining a suitable environment for semiconductor wafers still needs to be addressed.SUMMARY

[0007] Embodiments of the present disclosure address the above-described problems.

[0008] According to a first aspect of the invention, a wafer carrier is provided. The wafer carrier comprises (a) a wafer carrier housing having an interior space; and (b) a scavenging device with a scavenging compound in fluid communication with the interior space. In embodiments, the scavenging compound comprises an oxygen scavenging compound and / or a moisture scavenging compound.

[0009] According to a second aspect of the invention, a method of protecting a semiconductor wafer from contamination by oxygen and / or moisture is provided. The method comprises (i) selecting a wafer carrier as described in the first aspect; and (ii) arranging the semiconductor wafer to be protected within the interior space of the wafer carrier.

[0010] According to a third aspect of the invention, a use of a wafer carrier as described according to the first aspect for protecting a semiconductor wafer from contamination by oxygen and / or moisture is provided.

[0011] According to a fourth aspect of the invention, a novel scavenging device for cooperation with a wafer carrier housing is provided, the scavenging device having any feature of the scavenging device as described in the first aspect.DRAWINGS

[0012] FIG. 1 is a perspective view of a pouch during filling with scavenging compound, according to one or more embodiments shown and described herein;

[0013] FIG. 2 is a perspective view of a pouch filled with scavenging compound after closure, according to one or more embodiments shown and described herein;

[0014] FIG. 3 is a horizontal cross-section through a front opening unified pod (FOUP) showing two pouches of FIGS. 1 - 2 arranged in position on the FOUP, according to one or more embodiments shown and described herein;

[0015] FIG. 4 is a perspective view of a refill unit for receiving scavenging compound, according to one or more embodiments shown and described herein;

[0016] FIG. 5 is a back view of a frame for holding the refill unit of FIG. 4 with mounting structure, according to one or more embodiments shown and described herein;

[0017] FIG. 6 is a side view of the frame of FIG. 5 mounted on the FOUP, according to one or more embodiments shown and described herein;

[0018] FIG. 7 is a horizontal cross-section through a FOUP showing two frames of FIG. 5 holding refill units of FIG. 4 arranged in position on the FOUP, according to one or more embodiments shown and described herein;

[0019] FIG. 8 is a front view of the frame of FIG. 5 holding the refill unit of FIG. 4, according to one or more embodiments shown and described herein;

[0020] FIG. 9 is a perspective view of a framework container for receiving scavenging compound, according to one or more embodiments shown and described herein;

[0021] FIG. 10 is a perspective view of a partially assembled framework container of FIG. 9 during filling with scavenging compound, according to one or more embodiments shown and described herein;

[0022] FIG. 11 is a perspective view of the framework container of FIGS. 9 to 10 filled with scavenging compound after closure, according to one or more embodiments shown and described herein;

[0023] FIG. 12 is a horizontal cross-section through a FOUP showing two framework containers of FIGS. 9 to 11 arranged in position on the FOUP, according to one or more embodiments shown and described herein;

[0024] FIG. 13 is a perspective view of a frame in an open position for receiving a packet containing scavenging compound, according to one or more embodiments shown and described herein;

[0025] FIG. 14 is a perspective view of the packet of FIG. 13 received in the frame of FIG. 13 in an open position, according to one or more embodiments shown and described herein;

[0026] FIG. 15 is a perspective view of the packet of FIG. 13 received in the frame of FIG. 13 in a closed position, according to one or more embodiments shown and described herein;

[0027] FIG. 16 is a perspective view of the back side of the frame of FIG. 13 in a closed position, according to one or more embodiments shown and described herein;

[0028] FIG. 17 is an exploded perspective view of a FOUP incorporating a scavenging device, according to one or more embodiments shown and described herein;

[0029] FIG. 18 is a perspective view of the FOUP incorporating the scavenging device of FIG. 17 in an assembled state, according to one or more embodiments shown and described herein;

[0030] FIG. 19 is an exploded perspective view of a FOUP incorporating a scavenging device, according to one or more embodiments shown and described herein;

[0031] FIG. 20 is an exploded perspective view of an opening at the back of a FOUP and components of a scavenging device, according to one or more embodiments shown and described herein;

[0032] FIG. 21 is a perspective view of the back of a FOUP incorporating a scavenging device, according to one or more embodiments shown and described herein;

[0033] FIG. 22 is a front view through an open door of a FOUP incorporating a pair of nitrogen diffusers combined with scavenging devices, according to one or more embodiments shown and described herein;

[0034] FIG. 23 is a perspective view of the pair of the nitrogen diffusers combined with the scavenging devices for incorporation with the FOUP of FIG. 22, according to one or more embodiments shown and described herein;

[0035] FIG. 24 is a top view of the FOUP of FIG. 22 showing the position of the pair of nitrogen diffusers combined with scavenging devices, according to one or more embodiments shown and described herein;

[0036] FIG. 25 is a front view through an open door of FOUP incorporating a pair of nitrogen diffusers combined with scavenging devices, according to one or more embodiments shown and described herein;

[0037] FIG. 26 is a perspective view of the pair of nitrogen diffusers combined with the scavenging devices for incorporation with the FOUP of FIG. 25; and

[0038] FIG. 27 is a top view of the FOUP of FIG. 26 showing the position of the pair of nitrogen diffusers combined with the scavenging devices, according to one or more embodiments shown and described herein.DETAILED DESCRIPTION

[0039] Reference is made hereinafter to various embodiments of wafer carriers, methods of protecting semiconductor wafers from contamination by oxygen and / or moisture, and other aspects of the present invention.

[0040] The disclosure should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the subject matter to those skilled in the art.

[0041] Any aspect of any invention described herein may be combined with any feature described in any other aspect of any invention or embodiment described herein mutatis mutandis.

[0042] Terminology

[0043] Unless otherwise expressly defined, all technical and scientific terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art. Theterminology used in the disclosure herein is for describing particular embodiments only and is not intended to be limiting.

[0044] Unless otherwise expressly stated, it not intended that any method disclosed herein be construed as requiring that its steps be performed in a specific order, nor that any article set forth herein be construed as requiring specific orders or orientations to its individual components.

[0045] Unless otherwise expressly stated, it is intended that any composition or mixture disclosed herein may comprise, consist essentially of, or consist of the disclosed components.

[0046] As used herein, the singular form of a term is intended to include the plural form of the term, unless the context clearly indicates otherwise.

[0047] As used herein, numerical values are not strictly limited to the exact numerical value recited. Instead, unless otherwise expressly stated, each numerical value is intended to mean both the exact numerical value and “about” the numerical value, which encompasses a functionally equivalent range surrounding that numerical value, such that either possibility is contemplated as an embodiment disclosed herein.

[0048] As used herein, the term “formed from” (including related terms such as “forming”) refers to, with respect to an article (or component of an article) and a thermoplastic material, that the article (or component of the article) is extruded, molded, shaped, pressed, or otherwise made, in whole or in part, from the thermoplastic material under sufficient heating to enable such forming. As such, the term “formed from” (including related terms such as “forming”) means, in some embodiments, the article (or component of an article) can comprise, consist essentially of, or consist of, the material; and, in other embodiments, the article (or component of an article) consists of the material because the article (or component of an article) is, for example, made by an extrusion process or a molding process.

[0049] Wafer Carrier

[0050] According to an aspect of the invention, a wafer carrier comprises (a) a wafer carrier housing having an interior space; and (b) a scavenging device with a scavenging compound in fluid communication with the interior space. In embodiments, the scavenging compound may be an oxygen scavenging compound and / or a moisture scavenging compound.

[0051] The wafer carrier may be for enclosing wafers such as semiconductor wafers, and, in use, contains wafers within the interior space.

[0052] The scavenging compound, for example, the oxygen scavenging compound and / or the moisture scavenging compound is suitably arranged for fluid communication with a potential source of contamination, for example, a potential source of oxygen contamination and / or moisture contamination.

[0053] Accordingly, in embodiments, the wafer carrier may provide a microenvironment with oxygen and / or moisture control for semiconductor wafers enclosed within the carrier as they move through one or more fabrication process steps.

[0054] For example, the wafer carrier as disclosed herein may be a FOUP (a front opening unified pod) or a SMIF (standard mechanical interface) pod. A SMIF pod may be arranged, in use, to store a multiplicity of wafers horizontally. A bottom surface of a SMIF pod may include an opening door which is suitably pivotable between open and closed positions.

[0055] Wafer carriers according to the present disclosure may include any one or more features of a commercially available FOUP or SMIF pod to the extent such features do not negate or contradict any essential aspects of the present disclosure. The FOUP may be a standard FOUP or a nitrogen purge FOUP.

[0056] Wafer

[0057] In embodiments, one or more semiconductor wafers are present within the interior space.

[0058] The semiconductor wafers may have a diameter of at least 100 mm, or, in embodiments, at least 150 mm. For example, the semiconductor wafers may have diameters in the range 100 mm to 1000 mm, or, in embodiments, in the range 150 mm to 600 mm, or, in embodiments, in the range 150 mm to 500 mm.

[0059] For example, wafer diameters accommodated in a SMIF pod may be 150 mm or 200 mm; whereas a FOUP may accommodate larger diameter wafers, for example, 300 mm or 450 mm.

[0060] The container may contain at least 10 semiconductor wafers, for example, 10 to 50 or 10 to 25 wafers.

[0061] Wafer Carrier Housing

[0062] The wafer carrier as disclosed herein comprises a wafer carrier housing having an interior space.

[0063] The wafer carrier housing has an interior space adapted to contain one or more semiconductor wafers. The housing may include a door for providing access to the interior space. The door may include a door housing and a latching mechanism operably coupled with the door housing to secure the door closed. The door may be openable for access to the interior space, for example, pivotable or removable, and, in use, to a multiplicity of wafers which may be stored in the interior space. The door may define an interior side facing the interior space. The door may be a front-opening door.

[0064] The wafer carrier, for example the interior space thereof, may include support means for supporting a plurality of wafers. The wafer carrier, for example the interior space thereof, may be arranged to contain at least 10 silicon wafers. In use, when containing silicon wafers, the wafer carrier may have a weight of at least 1 kg or at least 5 kg.

[0065] The wafer carrier may have a maximum external width of at least 30 cm, or, in embodiments, at least 40 cm; and, in embodiments, less than 80 cm or less than 60 cm. The wafer carrier may have a maximum external depth of at least 20 cm, or, in embodiments, at least 30 cm; and, in embodiments, less than 60 cm or less than 45 cm. The wafer carrier may have a maximum external height of at least 20 cm, or, in embodiments, at least 30 cm; and, in embodiments, less than 60 cm or less than 45 cm. The wafer carrier may have an external volume of at least 20,000 cm3, or, in embodiments, at least 40,000 cm3; and, in embodiments, the external volume may be less than 100,000 cm3.

[0066] The wafer carrier may be made from any suitable material or combination of materials. The wafer carrier housing of the wafer carrier may comprise a barrier material which is, for example, a thermoplastic material. In embodiments, the wafer carrier, for example the housing, may comprise an ESD (electrostatic discharge) material. The thermoplastic may be selected from a polycarbonate, a cyclic olefin polymer (COC) and a cyclic olefin copolymer (COP). In oneembodiment, the housing may comprise a carbon-filled thermoplastic polymer, for example, a polycarbonate carbon-filled material.

[0067] In embodiments, the housing of the wafer carrier may be a Standard FOUP or a nitrogen purge FOUP.

[0068] In embodiments, the wafer carrier suitably includes wafer supports and / or wafer contact areas. Such supports and / or areas may comprise the same material as described for the housing or may comprise an alternative material. For example, an alternative material may be a polyaryl etherketone, for example, PEEK.

[0069] Scavenging Device

[0070] The wafer carrier as disclosed herein comprises a scavenging device with a scavenging compound in fluid communication with the interior space.

[0071] In embodiments, the scavenging device may comprise a retaining component which retains the scavenging compound within a predetermined volume. The retaining component is suitably arranged to restrict and / or prevent passage of any of the scavenging compound outside of the scavenging device. For example, the retaining component may confine the scavenging compound to remaining within the scavenging device; and / or it may prevent passage of the scavenging compound into the interior space of the housing in circumstances where it can move freely within the interior space, for example unconstrained by the scavenging device.

[0072] Thus, the retaining component may help to prevent contamination of the interior space and / or any wafers therein by the scavenging compound. For example, in some embodiments, the scavenging device may include a scavenging compound which includes a metal. The scavenging device is suitably arranged so that any metal of the scavenging compound cannot contaminate wafers which may be associated with the wafer carrier.

[0073] In embodiments, the retaining component may comprise a barrier which is positioned between the interior space and the scavenging compound and is arranged to restrict and / or prevent passage of the scavenging compound into the interior space. The barrier, however, is preferablypermeable to oxygen and / or moisture so that, suitably, oxygen and / or moisture can pass from the interior space to the scavenging compound via the barrier.

[0074] In embodiments, the barrier may include pores having diameters of at least 1 pm, or at least 5 pm, or at least 9 pm, for example, at least 10 pm; and, suitably, less than the smallest diameter of any scavenging compound which may be contained within the predetermined volume of the scavenging device. For example, as described elsewhere herein, the scavenging compound may be in the form of particles having a particle size of at least 2 pm, for example, in the range from 2 to 1000 pm. In some cases, the scavenging compound may be in the form of pellets or granules having a largest dimension of at least 1 mm, for example, in the range from 1 to 10 mm.

[0075] In embodiments, the retaining component may comprise a receptacle which may contain the scavenging compound, which may comprise a mass of particles of the scavenging compound. The receptacle may be flexible, semi-rigid, or rigid. Alternatively, and / or additionally, the retaining component may be defined by a polymeric material and the scavenging compound may be embedded in the polymeric material so that the polymeric material and scavenging compound define a solid mass, wherein suitably the scavenging compound is immovable within the solid mass.

[0076] In embodiments, the scavenging device may include both a retaining component which comprises a barrier and a polymeric material in which the scavenging compound is embedded.

[0077] In embodiments, the scavenging device may comprise at least one component in which the scavenging compound is retained or embedded, wherein the at least one component is releasably secured relative to the wafer carrier housing.

[0078] Thus, the scavenging compound, at least, can suitably be removed from the wafer carrier and / or from the wafer carrier housing, for example when exhausted or it otherwise needs replenishing. In embodiments wherein the scavenging device includes a retaining component which comprises a receptacle which may contain the scavenging compound, it is preferred that the receptacle is releasably secured relative to the wafer carrier housing. For example, in embodiments, the scavenging device may be releasably securable to a door of the wafer carrier housing.

[0079] In some embodiments, as further described elsewhere herein, the scavenging device may be positioned either within the interior space or outside the interior space. In other embodiments, a first scavenging device with a first scavenging compound may be positioned within the interior space, and a second scavenging device with a second scavenging compound may be positioned outside the interior space.

[0080] Within the Interior Space

[0081] In embodiments, the scavenging device may be positioned within the interior space of the wafer carrier housing.

[0082] When the scavenging device is within the interior space, the scavenging device may include a retaining component which retains the scavenging compound within the predetermined volume as described. The scavenging device may include a first securement element which is arranged to be releasably secured at a position within the housing. In one embodiment, the first securement element may be arranged to cooperate with a second securement element arranged within the housing, for example the interior space thereof. The first and second securement elements are preferably arranged to cooperate for releasably securing the scavenging device within the interior space. For example, the first and second securement elements may comprise cooperable male and female elements (e.g., a hook within the housing being arranged to engage an opening in the scavenging device) or may otherwise be releasably engageable with one another. Alternatively, the first securement element may comprise a face which is arranged to releasably engage an area within the housing for releasably securing the scavenging device in position. The face may comprise adhesive, for example an adhesive pad, which is arranged to contact an area within the housing for releasably securing the scavenging device in position.

[0083] Examples of arrangements wherein the scavenging compound is within the interior space are described below as Embodiments A to D and H.

[0084] In Embodiment A, the scavenging device may comprise a flexible receptacle, for example a pouch. The flexible receptacle suitably acts as a retaining component to retain the scavenging compound within a predetermined volume and provides a barrier to restrict and / or prevent passage of scavenging compound into the interior space. The flexible receptacle preferablycomprises, or more preferably consists essentially of, a porous material which may be a polymeric material, for example a polyolefin such as polyethylene or polypropylene, especially HDPE. The polymeric material may be heat-sealed to define the receptacle. The receptacle may include a first securement element, for example an opening, for cooperating with a second securement element in the interior of the housing for releasably securing the scavenging device in position. Preferably, the scavenging compound is arranged within the pouch. The scavenging compound may comprise particles which are arranged to be confined within the receptacle. The particles of the scavenging compound may be as described above.

[0085] Embodiment A may be as described hereinafter with reference to FIGS. 1 to 3.

[0086] In Embodiment B, the scavenging device may comprise a semi-rigid receptacle, for example comprising a rigid frame which is arranged to releasably engage permeable refills. The refills may include a retaining component to retain the scavenging compound within a predetermined volume and provides a barrier to restrict and / or prevent passage of scavenging compound into the interior space. The refills preferably comprise a porous material which may be a polymeric material, for example a polyolefin such as polyethylene or polypropylene, especially HDPE. The scavenging device may include a securement element for securing the device in position within the interior space. The scavenging compound may comprise particles which are arranged to be confined within the refill. The particles of the scavenging compound may be as described above.

[0087] Embodiment B may be as described hereinafter with reference to FIGS. 4 to 8.

[0088] In Embodiment C, the scavenging device may be substantially rigid. It may include a rigid framework. Between elements of the framework, permeable regions may be defined, for example by a porous material which may be a polymeric material, for example a polyolefin such as polyethylene or polypropylene, especially HDPE. The framework may include cooperable panels which include the permeable regions. The cooperable panels may be pivotable relative to one another to define a hollow, rigid receptacle in which the scavenging compound may be arranged. The scavenging compound may comprise particles which are arranged to be confined within the receptacle. The particles of the scavenging compound may be as described above. The scavenging device may include one or a plurality of securement elements for cooperating with oneor a plurality of securement elements in the interior of the housing for releasably securing the scavenging device in position.

[0089] Embodiment C may be as described hereinafter with reference to FIGS. 9 to 12.

[0090] In embodiment D, the scavenging device may include a first securement element which may be substantially planar and / or may include a face which is arranged to be secured in position by making face to face contact with a surface within the interior space of the wafer carrier housing and / or defined by an inside surface of the wafer carrier housing. The first securement element may be secured in position by adhesive means. Preferably, the first securement element comprises an adhesive, for example being part of an adhesive film or pad (or the like), which is arranged to be releasably secured by adhesion to the surface within the interior space of the wafer carrier housing.

[0091] The scavenging device of Embodiment D may comprise a scavenger housing containing a scavenging compound and / or scavenger composition. The scavenger housing may include the first securement element as described, for example associated with a substantially planar face of the housing. The scavenging compound may be releasably secured within the housing so that the compound and / or composition may be replaced and / or replenished as may be desired in use. The scavenging compound may be within a body, for example a flexible receptacle such as a pouch. The flexible receptacle suitably acts as a retaining component to retain the scavenging compound within a predetermined volume and provide a barrier to restrict and / or prevent passage of scavenging compound into the interior space. The flexible receptacle preferably comprises, or more preferably consists essentially of, a porous material which may be a polymeric material, for example a polyolefin such as polyethylene or polypropylene, especially HDPE. The polymeric material may be heat-sealed to define the receptacle. Preferably, the scavenging compound is arranged within the flexible receptacle. The scavenging compound may comprise particles which are arranged to be confined within the receptacle. The particles of the scavenging compound may be as described above.

[0092] The scavenger housing of Embodiment D may be arranged to retain the flexible receptacle in position and allow passage of oxygen and / or moisture to the receptacle so the oxygen and / or moisture can pass into the receptacle. The housing preferably includes one or more openings for passage of oxygen and / or moisture as aforesaid. The opening(s) may be defined in a face ofthe housing and the face may include at least 50%, or at least 75%, of its area defined by one or more openings, suitably with the remainder of the face defined by solid material of the scavenger housing.

[0093] The scavenger housing of Embodiment D may include a first member which may include the first securement element and a second member which may include one or more openings for passage of oxygen and / or moisture as aforesaid, wherein the first member and second member are movable, preferably pivotable, relative to one another, to releasably secure a body, for example flexible receptacle containing the scavenging compound and / or composition, in position.

[0094] The scavenger housing of Embodiment D may have a thickness A, when in a configuration in which it secures the body, for example the flexible receptacle, in position, and a maximum dimension B, wherein a ratio of dimension B divided by thickness A is at least 5, preferably at least 7, more preferably at least 10. The ratio may be less than 100 or less than 50. Thus, the housing is suitably in the form of a laminar or thin plate.

[0095] Embodiment D may be as described with reference to FIGS. 13 to 16.

[0096] In an embodiment H, the scavenging device may be associated with a nitrogen diffuser of the wafer carrier. For example, the nitrogen diffuser may be positioned inside the wafer carrier housing and may include a chamber which is arranged to fluidly communicate with a supply of nitrogen and arranged to deliver the nitrogen into the interior space of the wafer carrier housing.

[0097] The scavenging device may include a chamber in which a scavenging compound is arranged. The scavenging device may comprise a solid body which includes the scavenging compound. For example, the solid body may have a volume of at least 1cm3, for example at least 2 cm3, at least 5cm3, at least 10 cm3, or at least 20 cm3. The volume may be less than 45 cm3. Alternatively, a chamber may include a flexible or rigid receptacle to restrict and / or prevent passage of the scavenging compound into the interior space, however, is preferably permeable to oxygen and / or moisture. Preferably, the chamber of the scavenging device is in fluid communication with the interior space of the wafer carrier housing. In use, oxygen and / or moisture may be scavenged from the interior space of the wafer carrier housing by passage of oxygen and / or moisture from the interior space to the chamber of the scavenging device.

[0098] The scavenging device may be releasably secured to, for example directly to, the nitrogen diffuser, for example by one or more straps or the like. Alternatively, the scavenging device and the nitrogen diffuser may be components of a unitary molding. The respective chambers of the scavenging device and the nitrogen diffuser may be separate and / or independent parts of the unitary molding.

[0099] The embodiment H may be as described hereinafter with reference to FIGS. 22 to 27.

[0100] Outside the Interior Space

[0101] In some embodiments, the scavenging device may be positioned outside the interior space, for example, outside an outwardly facing wall of the wafer carrier housing.

[0102] When the scavenging device is at least partially, for example, substantially entirely, outside the housing, it is preferred that the scavenging compound is at least partially, for example substantially entirely, outside the interior space of the wafer carrier housing.

[0103] Examples of arrangements wherein the scavenger compound are outside the interior space are described below as Embodiments E to G.

[0104] In Embodiment E, the scavenging device may comprise a rigid scavenger housing which is arranged to be releasably secured on the outside of the wafer carrier housing. The scavenger housing preferably contains the scavenging compound which may comprise a mass of particles which are free-flowing within the housing but are suitably restricted or preferably substantially prevented from passing from the housing and into the interior space.

[0105] The scavenger housing may be arranged to cooperate with a securement opening in the wafer carrier housing, for example in a side wall thereof. Preferably, a permeable membrane is arranged between the interior space of the wafer carrier housing and an interior space of the scavenger housing, wherein the permeable membrane is preferably arranged to be permeable to oxygen and / or moisture but be impermeable to scavenging compound contained within the scavenger housing. The scavenger housing may be releasably secured relative to the securement opening. The wafer carrier housing may include two securement openings, suitably defined in opposing side walls of the wafer carrier housing. Preferably, a single scavenger housing is arrangedto engage both of the securement openings. For example, the scavenger housing may include spaced apart openings which are arranged to cooperate with the two securement openings so that oxygen and / or moisture can pass from the interior space of the wafer carrier housing into the scavenger housing via both of the openings and suitably then contact the scavenging compound contained within the scavenger housing.

[0106] A part of the scavenger housing may be arranged to make face to face contact with an outer area of the wafer carrier housing and / or to extend across an outwardly facing area of a wall of the wafer carrier housing.

[0107] Embodiment E may be as described hereinafter with reference to FIGS. 17 and 18.

[0108] In an Embodiment F, the scavenging device suitably comprises a solid body which may comprise a scavenging compound.

[0109] The solid body is preferably positioned outside the interior space of the wafer carrier housing. It may be releasably secured relative to an outer wall of the wafer carrier housing. The body may be arranged within an opening in the outer wall. A porous member may be positioned between the interior space of the wafer carrier housing and the solid body. A securement means may be provided for releasably securing the solid body in position. The securement device may comprise a closure which is preferably substantially impermeable to oxygen and / or moisture, wherein preferably the closure is positioned outside the solid body and / or the solid body is arranged between the wafer carrier housing and the closure. The closure may be arranged to screw- threadedly engage another part, for example a part fixed relative to the wafer carrier housing, for releasably securing the closure in position.

[0110] The solid body may have a thickness C and a maximum dimension D, wherein a ratio of dimension D divided by thickness C is at least 5, preferably at least 7, more preferably at least 10. The ratio may be less than 100 or less than 50. Thus, the solid body is suitably in the form of a laminar or thin plate. The solid body may comprise a disc.[0U1] The wafer carrier housing may include openings in outer walls, preferably opposing outer walls, and a respective solid body may be associated with each opening. Each solid body ispreferably secured in position by a securement device, for example a respective the closure as described.

[0112] Embodiment F may be as described hereinafter with reference to FIG. 19.

[0113] In an embodiment G, the scavenging device may be releasably secured within an opening in a wall of the wafer carrier housing. The scavenging device may comprise a solid body which may comprise the scavenging compound.

[0114] The solid body may be a component of a scavenging assembly which may comprise first and second housing parts with the solid body positioned there between. The solid body is preferably substantially encased and / or encapsulated for example by cooperating first and second housing parts. The first and second housing parts may cooperate to releasably secure the solid body in position. For example, the first housing part may be arranged on a side of the opening in the wall of the wafer carrier housing which is within the interior space of the wafer carrier housing (or defines an internal wall of the interior space) and the second housing part may be outside the interior space. The first housing part may be permeable to oxygen and / or moisture so that the aforesaid may pass from the interior space, through the first housing part and the opening in the wall and into the solid body where scavenging may take place. The first housing part restrict and / or prevent passage of the scavenging compound into the interior space. The second housing part may be substantially impermeable.

[0115] Embodiment G may be as described hereinafter with reference to FIGS. 20 and 21.

[0116] Scavenging Compound

[0117] The wafer carrier as disclosed herein comprises a scavenging device with a scavenging compound in fluid communication with the interior space.

[0118] In embodiments, the scavenging compound may be a moisture scavenging compound and / or an oxygen scavenging compound.

[0119] In embodiments, a scavenging device as described may include both a moisture scavenging compound and an oxygen scavenging compound. For example, when a wafer carrierincludes both an oxygen scavenging compound and a moisture scavenging compound, a mass comprising oxygen scavenging compound may be mixed with a mass comprising moisture scavenging compound. For example, in embodiments which include a scavenging device which contains pellets or powder, the pellets or powder may comprise pellets or powder comprising oxygen scavenging compound and pellets or powder comprising moisture scavenging compound, suitably in intimate contact with one another and / or mixed together.

[0120] In embodiments, the scavenging compound may be a component of a scavenging composition (i.e., a scavenging composition may comprise the scavenging compound and optionally one or more other components). Thus, as used herein, the term “scavenging compound” contemplates the possibility that the scavenging compound may be a component of a scavenging composition; and, where the term “scavenging compound” is used herein, it also may be understood to refer to a scavenging composition comprising the scavenging compound. Hence, the scavenging compound may be a moisture scavenging compound and / or a component of a moisture scavenging composition. Likewise, the scavenging compound may be an oxygen scavenging compound and / or a component of an oxygen scavenging composition.

[0121] In embodiments, the scavenging compound and / or the scavenging composition may be particulate. In this case, particles are preferably sized so that they substantially cannot pass through openings, for example, pores, defined in the barrier. Particles of the scavenging compound and / or the scavenging composition may be at least 2 pm, for example, in the range from 2 to 1000 pm. In some cases, the scavenging compound and / or the scavenging composition may be in the form of pellets or granules having a largest dimension of at least 1 mm, for example, in the range from 1 to 10 mm. Preferably, as stated, substantially none of the scavenging compound or scavenging composition can pass through the barrier defined by the retaining component.

[0122] Moisture Scavenging Compound

[0123] In embodiments, the scavenging compound may be a moisture scavenging compound.

[0124] Suitable moisture scavenging compounds may include conventional or commercially available moisture scavenging compounds. One type of moisture scavenging compound may be used alone or in combination with one or more other types of moisture scavenging compound.

[0125] In embodiments, the moisture scavenging compound may be inorganic or organic; and / or it may be polymeric or non-polymeric; and / or it may comprise one or more petroleumbased polymeric materials, inorganic materials, or bio-based materials.

[0126] In an Embodiment I, the moisture scavenging compound may be arranged to generate molecular hydrogen on reaction with moisture. Thus, in this case, the moisture is scavenged by a chemical reaction involving the moisture and the moisture scavenging compound.

[0127] Further, in Embodiment I, the moisture scavenging compound may comprise a matrix in which an active material which is arranged to generate molecular hydrogen on reaction with moisture is associated, for example embedded or preferably dispersed.

[0128] Suitable polymeric matrix materials may be selected based on the solubility of moisture in the bulk polymer. Suitable polymeric matrix materials include but are not limited to polyolefins, low density polyethylene, high density polyethylene, polypropylene, styrene-ethylene-butylene (SEBS) copolymers, nylon 6, styrene, styrene-acrylate copolymers, and ethylene vinyl acetate. The matrix may be a polymeric matrix and the active material may be dispersed therein.

[0129] In embodiments, the polymeric matrix may include at least 1 wt% of active material, preferably at least 2 wt%. The polymeric matrix may include less than 70 wt% of active material. Suitably, the polymeric matrix includes 1-50 wt%, preferably 2-40 wt% of active material. The balance of material in the polymeric matrix may predominantly comprise polymeric material.

[0130] In embodiments, the active material may comprise a metal and / or a hydride. The metal may be one or more of sodium, lithium, potassium, magnesium, zinc, and aluminum. The hydride may be inorganic, for example it may comprise a metal hydride or borohydride; or it may be organic.

[0131] For example, active materials suitable for the release of molecular hydrogen as a result of contact with water include but are not limited to: sodium metal, lithium metal, potassium metal, calcium metal, sodium hydride, lithium hydride, potassium hydride, calcium hydride, magnesium hydride, sodium borohydride, and lithium borohydride.

[0132] Non-limiting examples of other active substances may include organic hydrides such as tetramethyl disiloxane and trimethyl tin hydride, as well as metals such as magnesium, zinc, oraluminum. Where the rate of reaction between the active material and water is too slow, the addition of hydrolysis catalysts and / or agents are explicitly contemplated. For example, the rate of hydrolysis of silicon hydrides may be enhanced by the use of hydroxide or fluoride ions, transition metal salts, or noble metal catalysts.

[0133] In embodiments, the active material may also be the polymeric matrix. For example, polymeric silicon hydrides such as poly(methylhydro)siloxane provide both a polymeric matrix and an active substance capable of releasing molecular hydrogen when in contact with moisture. In embodiments, the active material may be a polymer bound material such as a polymer bound borohydride.

[0134] In embodiments, the moisture scavenging compound and / or active material comprises calcium hydride.

[0135] In an Embodiment II, the moisture scavenging compound may be inorganic and may be a porous inorganic material, suitably arranged to absorb water into pores defined in the material and retain the absorbed water therein. Such a moisture scavenging compound may comprise one or more of a metal silicate (for example a molecular sieve, magnesium aluminum silicate or a zeolite), fumed silica, amorphous silica (for example a silica gel), activated alumina, activated charcoal, silicon dioxide, mesoporous silica, a clay, or a bentonite.

[0136] In an Embodiment 111, the moisture scavenging compound may be inorganic and may be an oxide. It may be an oxide of a Group I or Group II metal (for example sodium oxide or calcium oxide), a mixed metal oxide (for example soda-lime), or an oxide containing phosphorous (for example phosphorous pentoxide).

[0137] In an Embodiment IV, the moisture scavenging compound may be inorganic and may be a salt. It may be a salt of a Group I or Group II metal with the counterion being a sulfate (for example sodium sulfate or calcium sulfate) or a carbonate (for example potassium or magnesium carbonate).

[0138] In an Embodiment V, the moisture scavenging compound may be inorganic and may a hydroxide. It may be a Group I or Group II hydroxide (for example potassium hydroxide or magnesium hydroxide).

[0139] In an Embodiment VI, the moisture scavenging compound may be inorganic and may a halide (for example calcium chloride or lithium bromide).

[0140] In an Embodiment VII, the moisture scavenging compound may be a polymeric material, preferably a hygroscopic material, which may comprise one or more of alcohol- or acrylate-functionalised polymers such as polyvinyl alcohol, ethylene vinyl alcohol and polyacrylates.

[0141] In an Embodiment VIII, the moisture scavenging compound may be a hygroscopic biobased material. For example, it may comprise one or more of polycaprolactone (PCL), starches (for example corn or rice starch), sugars, fibers (for example cotton fibers, water hyacinth fibers, sisal fibers, hemp fibers, and agave fibers).

[0142] In embodiments, the moisture scavenging compound may be selected from one or more of anhydrous calcium chloride, soda-lime, silicon dioxide, mesoporous silica, magnesium aluminum silicate, molecular sieves, silica gels, and clays.

[0143] In embodiments, the moisture scavenging compound may be selected from one or more of polycaprolactone (PCL), starch, cotton fibers, and water hyacinth fibers.

[0144] When the moisture scavenging compound is particulate, particle sizes of particles of the compound may be selected to optimize scavenging.

[0145] In embodiments, the compound is preferably in the form of particles. Particles of the compound may have a d50 of less than 50pm, preferably less than 25pm, more preferably less than 10pm and, especially, 5pm or less. In some embodiments, the particles may have a d50 of less than 2pm. The d50 of the particles may be greater than lOnm, for example greater than 20nm. The d50 may be measured by Laser Diffraction, for example using a Beckman Coulter LS230 Laser Diffraction Particle Size Analyzer.

[0146] In embodiments, less than 5 vol%, less than 3 vol%, or less than 1 vol% of the particles have a particle size measured by Laser Diffraction as described herein of more than 100pm or more than 5pm. Suitably, less than 5 vol% of the particles have a particle size of more than 5pm. Suitably, more than 5 vol%, preferably more than 25 vol%, more preferably more than 50 vol%, especially more than 75 vol% of the particles have a particle size of more than 20nm.

[0147] The particle size distribution may be expressed by “span (S)” where S is calculated by the following equation:

[0148] S = (d90-dl0) / d50

[0149] where d90 represents a particle size in which 90% of the volume is composed of particles having a smaller diameter than the stated d90; and dlO represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated dlO; and d50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d50 value, and 50% of the volume is composed of particles having a diameter smaller than the stated d50 value. Particle size distributions of particles in which the span (S) is from 0.01 to 10, or from 0.01 to 5, or from 0.1 to 3, for example, may be preferred.

[0150] Moisture Scavenging Composition

[0151] In embodiments, the moisture scavenging compound may be a component of a moisture scavenging composition.

[0152] Suitably, the moisture scavenging composition, which includes the moisture scavenging compound, is provided in the wafer carrier in fluid communication with the interior space.

[0153] The moisture scavenging composition suitably includes the moisture scavenging compound.

[0154] In embodiments, the moisture scavenging composition may comprise the moisture scavenging compound (for example particles thereof) associated with (for example dispersed in) a polymer matrix. Examples of polymer matrix include, but are not limited to, polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polyolefin copolymers, polystyrene, polystyrene copolymers, polyacrylates, polymethacrylates, polyesters, polyvinylchloride, fluoropolymers, polyamides, polyether imides, polyphenylene sulfides, polysulfones, polyacetals, polycarbonates, polyphenylene oxides, polyurethanes, thermoplastic elastomers, epoxies, alkyds, melamines, phenolics, ureas, vinyl esters, liquid crystal polymers, cellulose, thermoplastic starch, polyhydroalkanates, polylactic acid, or combinations therof.

[0155] Particles of the moisture scavenging compounds of Embodiments I to VI in particular may be associated with, for example dispersed, in the polymer matrix to form at least part of the moisture scavenging composition.

[0156] In addition to the moisture scavenging compound, an oxygen scavenging compound may also be in fluid communication with the interior space.

[0157] Oxygen Scavenging Compound

[0158] In embodiments, the scavenging compound may be an oxygen scavenging compound.

[0159] Suitable oxygen scavenging compounds may include conventional or commercially available oxygen scavenging compounds. One type of oxygen scavenging compound may be used alone or in combination with one or more other types of oxygen scavenging compound.

[0160] In embodiments, the oxygen scavenging compound includes oxygen scavenging segments. For example, the oxygen scavenging compound may be an oxidizable organic compound. For further example, the oxygen scavenging compound may be an oxygen scavenging polymer or copolymer.

[0161] In an embodiment Al, the oxygen scavenging compound may be an ethyl enically- unsaturated compound, an amide-containing compound, for example an aliphatic or at least partially aromatic polyamide and / or a polyester modified by inclusion of ether moieties, for example, as in a polyether-polyester.

[0162] When the oxygen scavenging compound is an ethylenically-unsaturated compound, the compound may include at least two double bonds. For example, it is poly (ethylenically- unsaturated). In embodiments, it is a polymer. For example, it is a polymer which includes a repeat unit of formula I:

[0163] -[CH2-CR1=CR2-CH2-]n (I)

[0164] wherein R1and R2independently represent hydrogen atoms or optional -substituents which may be optionally-substituted alkyl groups. In embodiments, n may be greater than 0, greater than 1, greater than 2, greater than 10, greater than 100, or greater than 1000.

[0165] In embodiments, double bonds in the compound may be conjugated.

[0166] In the embodiment Al, the oxygen scavenging compound may be a polybutadiene- based polymer, a farnesene -based polymer, or a polyisoprene-based polymer. Such polymers, for example, polybutadiene-based polymers, may include terminal -OH, -COOH, or -NH2 moieties or may essentially not include terminal functionality. For example, polybutadiene-based polymers may include hydroxyl -terminated polybutadiene (PBD-OH) or elastomeric polybutadiene (E- PBD), the latter may essentially not include terminal functionality.

[0167] In an embodiment A2, the oxygen scavenging compound may be a copolymer. In this case, it is an oxygen scavenging copolymer which may include segments of oxygen scavenging moieties, referred to as “oxygen scavenging moiety segments” or OSM segments.

[0168] For example, the copolymer may include polycondensate segments (and, in embodiments, the copolymer predominantly comprises polycondensate segments) and OSM segments (and, in embodiments, the copolymer includes a lesser wt% of OSM segments compared to the wt% of polycondensate segments).

[0169] The OSM segments may be present in an amount necessary to impart the degree of oxygen scavenging capacity needed for a particular application. In embodiments, the OSM segments may be comprised of polyolefin oligomer segments which have been incorporated into the oxygen scavenging copolymer. However, other oxygen scavenging moiety segments such as polypropylene oxide oligomers and methyl pendant aromatic compounds may be included in the oxygen scavenging copolymer.

[0170] The OSM segments of the oxygen scavenging copolymer may be produced by reaction of an OSM segments precursor with a polymer (referred to as “polymer XI”), for example a polyester. The OSM segments precursor may be at least singly functionally terminated with a group capable of entering into polycondensation polymerization and / or capable of reaction with previously formed moieties of polymer XI to form new covalent bonds. Alternately, the OSM segments precursor can react with polymer end groups to provide a copolymer structure. A functionally terminated OSM segments precursor may be represented by formula II:

[0171] X-(OSM)-Y (II)

[0172] Double functionality is shown in formula II as one possibility, but the OSM segments precursor may be singly functionally terminated or functionalized to a degree greater than two. Those of ordinary skill in the art will recognize that the commercial availability of functionally terminated OSM segments precursors will obviate the need to add such functionalization. The OSM segments precursors of formula II are suitably selected to be readily oxidizable at ambient temperature, such that its auto-oxidation does not result in the generation of significant volatile or extractable by-products. In embodiments, OSM segment precursors may include polyolefin oligomers of molecular weight 100 to 10,000, polypropylene oxide oligomers, or methyl pendant aromatic compounds.

[0173] In embodiments, the OSM segments precursor may include a polybutadiene moiety. A polybutadiene moiety, when incorporated as segments in a the oxygen scavenging copolymer, may advantageously provide suitable oxygen scavenging. For example, such OSM segments may be derived from unhydrogenated polybutadiene oligomer of MW 1,000 to 3,000. In formula II, X and Y are typically the same and may be any species capable of entering into polycondensation and / or transesterification, with polymer XI . A non-limiting list of possible species represented by X or Y includes -OH, -COOH, -NH2, epoxides, and substituted derivatives thereof capable of entering into step-growth, condensation and / or transesterification reactions, for example with polymer XI.

[0174] In one example of embodiment A2, the oxygen scavenging copolymer may include OSM segments derived from a polyolefin oligomer and / or which includes a polyolefin oligomeric chain. In another example, the oxygen scavenging copolymer may include OSM segments derived from a polybutadiene oligomer and / or which includes a polybutadiene oligomeric chain. The aforementioned OSM segments are suitably covalently bonded to polymer XI, for example, of a polyester, such as PET segments, of the oxygen scavenging copolymer.

[0175] In embodiments, the oxygen scavenging copolymer may include at least 60 wt% or at least 75 wt% of polyester segments (e.g., polyethylene terephthalate segments) based on the weight of the oxygen scavenging copolymer. In embodiments, the oxygen scavenging copolymer may include up to 25 wt% of OSM segments, for example, polyolefin oligomer segments which may be derived from a polybutadiene polymer and / or comprise polybutadiene oligomeric chains. The oxygen scavenging copolymer suitably includes 75 to 99.5 wt%, or 75 to 85 wt%, or 77 to 82wt% of polyester segments (e.g. polyethylene terephthalate segments) and 0.5 to 25 wt%, or 15 to 25wt%, or 18 to 23 wt%, of polyolefin oligomer segments (e.g., derived from a polybutadiene polymer and / or comprising polybutadiene oligomeric chains).

[0176] In an embodiment A2 where the oxygen scavenging compound is a copolymer as described, for example including OSM segments copolymerization into polymer XI, the compound may further include chain extender moieties, for example derived from an anhydride, for example, an anhydride which includes more than one reactive moiety, for example pyromellitic dianhydride (PMDA) or maleic anhydride. The chain extender described may facilitate compatibilization of the oxygen scavenger moieties.

[0177] Oxygen Scavenging Composition

[0178] In embodiments, the oxygen scavenging compound may be a component of an oxygen scavenging composition.

[0179] Suitably, the oxygen scavenging composition, which includes the oxygen scavenging compound, is provided in the wafer carrier in fluid communication with the interior space.

[0180] The oxygen scavenging composition suitably may include the oxygen scavenging compound and a catalyst, for example, a transition metal catalyst, suitable for catalyzing oxygen scavenging reaction between the oxygen scavenging compound and oxygen which may be present in use in the wafer carrier.

[0181] The catalyst may be in the form of a salt, with the transition metal selected from the first, second or third transition series of the Periodic Table. Suitable metals and their oxidation states include, but are not limited to, manganese II or III, cobalt II or III, nickel II or III, copper I or II, rhodium II, III or IV, and ruthenium. It is preferred that the catalyst does not contain iron. The oxidation state of the metal when introduced does not need necessarily to be that of the active form. The metal may be nickel, manganese, cobalt or copper; more preferably manganese or cobalt; and even more preferably cobalt. Suitable counterions for the metal include, but are not limited to, chloride, acetate, propionate, oleate, stearate, palmitate, 2-ethylhexanoate, neodecanoate or naphthenate.

[0182] The transition metal catalyst may be selected from cobalt stearate, cobalt oleate, cobalt linoleate, cobalt acetyl acetonate, cobalt neodecanoate, manganese stearate, manganese oleate, manganese linoleate, and manganese acetylacetonate.

[0183] In embodiments, the oxygen scavenging composition may include a transition metal catalyst which is a cobalt catalyst. The catalyst may include an organic counter-ion. The catalyst may be selected from cobalt stearate, cobalt oleate, cobalt linoleate and cobalt acetylacetonate.

[0184] The oxygen scavenging composition may include at least 0.009 wt%, or at least 0.09 wt%, of transition metal catalyst. The composition suitably include less than 1.50 wt%, or less than 1.00 wt%, of transition metal catalyst. The aforementioned amounts suitably refer to the amount of transition metal, excluding any counter-ion or the like.

[0185] In embodiments, the oxygen scavenging composition may include at least 0.009 wt%, or at least 0.09 wt%, of cobalt moieties. The composition suitably includes less than 1.50 wt%, or less than 1.00 wt%, of cobalt moieties.

[0186] In embodiments, the oxygen scavenging composition may include at least 0.09 wt%, or at least 0.9 wt%, of transition metal catalyst compound, for example cobalt stearate. The composition suitably includes less than 15.0 wt%, or less than 10.0 wt%, of transition metal catalyst compound, for example cobalt stearate.

[0187] In embodiments, the oxygen scavenging composition may include at least 50 wt%, or at least 75 wt%, or at least 90 wt%, of thermoplastic polymers in total. For example, the thermoplastic polymers may be the oxygen scavenging compounds of embodiments Al and A2 and any thermoplastic polymer TP herein described. The composition suitably includes less than 99 wt%, or less than 98 wt%, of thermoplastic polymers in total.

[0188] The oxygen scavenging composition may include a thermoplastic polymer TP or a residue of a thermoplastic polymer TP. The thermoplastic polymer TP may be distinct from the oxygen scavenging compound in that the thermoplastic polymer TP is not covalently bonded to the oxygen scavenging compound; or, in some embodiments, at least some oxygen scavenging polymer may be covalently bonded to the thermoplastic polymer TP for example so that a copolymer is formed between at least between some of the oxygen scavenging polymer and thethermoplastic polymer TP (in which case the copolymer may include a residue of a thermoplastic polymer TP and a residue of the oxygen scavenging polymer).

[0189] When the oxygen scavenging composition is as described in embodiment Al and includes an oxygen scavenging compound which does not include relevant terminal functionality (e.g., it does not include terminal -OH, -COOH, or -NH2 moieties described), the oxygen scavenging compound may not be covalently bonded to the thermoplastic polymer TP. However, the oxygen scavenging composition may be made using an oxygen scavenging compound which includes relevant terminal functionality (e.g., terminal -OH, -COOH, or -NH2 moieties described) in which case the oxygen scavenging polymer may be covalently bonded to the thermoplastic polymer TP. In this latter case, the oxygen scavenging compound may be a copolymer as described in embodiment A2.

[0190] In embodiments, the thermoplastic polymer TP may be polar. For example, it may have polar functionality. For example, it may include carbonyl -containing groups (e.g., esters or ketones) or hydroxyl -containing groups (e.g., alcohols). In embodiments, it is thermoplastic. Hansen solubility parameters may be used to select suitable thermoplastic polymer TP. The parameters are a set of three parameters which numerically describe a material’s ability to dissolve in selected solvents: the ‘dispersion’ parameter (3d) describes a material’s dispersive forces, the ‘polarity’ parameter (8P) describes a material’s polarity, and the ‘hydrogen-bonding’ parameter (8h) describes a material’s ability to form hydrogen bonds. The parameters provide a quantitative way to distinguish “polar / non-polar” or “hydrophilic / hydrophobic” materials. If the thermoplastic polymer TP is non-polar or lacks hydrogen bonding (defined by a Hansen solubility parameter of 6p=0 and 6h=0, respectively) a relatively low amount of oxygen scavenging may take place. Alternatively, if the thermoplastic polymer TP is polar or contains hydrogen bonding, relatively high levels of oxygen scavenging may occur.

[0191] In embodiments, the thermoplastic polymer TP has 8P>0 and / or a 8h >0.

[0192] In embodiments, the thermoplastic polymer TP may be selected from polylactic acid, polyesters, polyethylene terephthalates, polycarbonates, polyolefins functionalized with carbonyl / carboxyl group. In further embodiments, the thermoplastic polymer TP may be selected from polylactic acid and / or polyesters, for example, polyethylene terephthalate.

[0193] In embodiments, addition of certain oils to the oxygen scavenging composition may enhance the oxygen scavenging ability (e.g., rate of scavenging).

[0194] In embodiments, the oil may be selected from:

[0195] (a) olive oil;

[0196] (b) macadamia oil;

[0197] (c) avocado oil;

[0198] (d) bataua oil;

[0199] (e) gevuina oil;

[0200] (f) an oil PQ comprising:

[0201] (i) less than 25 % of linoleic acid; and / or

[0202] (ii) less than 10 % of linolenic acid; and / or

[0203] (iii) greater than 40 % of oleic acid; and / or

[0204] (iv) greater than 40 % of monounsaturated fatty acids; and / or

[0205] (v) less than 40 % of polyunsaturated fatty acids; and / or

[0206] (vi) at least 0.1 % of squalene.

[0207] A reference to “ppm” or “parts-per-million” herein (or cognate expression) refers to the parts per million of a specified material by weight.

[0208] The % of components in oils, for example in an oil may be assessed by GC-HRMS. Analysis may be as described in, for example, “Column Selection for the Analysis of Fatty Acid Methyl Esters; Authors: Frank David, Pat Sandra, Allen K Vickers. Agilent Technologies 5989- 3760EN and the citations therein. The method involves derivatization of fatty acids to methyl esters as described in W.W. Christie, “Gas Chromatography and Lipids, A Practical Guide”, (1989), The Oily Press, Ayr, Scotland (ISBN O-9514171-O-X) and then analysis of the fatty acid methyl esters (FAMEs).

[0209] In embodiments, the oil PQ may have the following characteristics:

[0210] - less than 25 % of linoleic acid;

[0211] - less than 10 % of linolenic acid; and

[0212] - greater than 40 % of oleic acid.

[0213] In embodiments, the oil PQ may have the following characteristics:

[0214] - 1 to 15 %, preferably 2 to 10 % of linoleic acid;

[0215] - 0.1 to 10 %, preferably 0.1 to 5 %, of linolenic acid; and

[0216] - 40 to 80 %, preferably 45 to 70 %, of oleic acid.

[0217] In embodiments, the oil PQ may have the following characteristics:

[0218] - greater than 40 % of monounsaturated fatty acids;

[0219] - less than 40 % of polyunsaturated fatty acids; and

[0220] - at least 0. 1 % of squalene.

[0221] In embodiments, the oil PQ may have the following characteristics:

[0222] - 40 to 80 %, preferably 45 to 75 %, of monounsaturated fatty acids;

[0223] - 3 to 30 %, preferably 4 to 15 %, of polyunsaturated fatty acids; and

[0224] - 0.1 to 5.0 %, preferably 0.1 to 4.0 %, of squalene.

[0225] In embodiments, the oxygen scavenging composition may be in the form of a powder, compressed powder, film, pellets, compressed pellets or foam. It is preferably in the form of a powder, a compressed powder or a compressed pellet.

[0226] The oxygen scavenging composition (Composition I) may include:

[0227] (i) one or more thermoplastic polymers, wherein the sum of the wt% of thermoplastic polymers in the composition is in the range 50 to 99 wt%, or in the range 80 to 99 wt%; and

[0228] (ii) 0.009 wt% to 1.00 wt%, or 0.09 wt% to 1.00 wt%, of transition metal catalyst.

[0229] Unless otherwise stated, the balance of oxygen scavenging compositions may comprise other polymers or additives (eg oils as described) and / or a counter-ion for the transition metal catalyst.

[0230] The one or more thermoplastic polymers may include one or more oxygen scavenging compounds which may comprise a polymer or copolymer as described in embodiment Al or A2. An oxygen scavenging composition (Composition II) may include:

[0231] (i) one or more oxygen scavenging compounds, wherein the sum of the wt% of oxygen scavenging compounds in the composition is in the range 50 to 99 wt%, or in the range 80 to 99 wt%; and

[0232] (ii) 0.009 wt% to 1.00 wt%, or 0.09 wt% to 1.00 wt%, of transition metal catalyst.

[0233] The one or more oxygen scavenging compounds may comprise an ethylenically- unsaturated compound which may be included in a polymer or copolymer, for example as described in embodiments Al or A2. In this case, an oxygen scavenging composition (Composition III) may include:

[0234] (i) one or more oxygen scavenging compounds which include an ethylenically- unsaturated compound, wherein the sum of the wt% of ethylenically-unsaturated compounds in the composition is in the range 50 to 99 wt%, preferably in the range 80 to 99 wt%; and

[0235] (ii) 0.009 wt% to 1.00 wt%, preferably 0.09 wt% to 1.00 wt%, of transition metal catalyst.

[0236] The one or more oxygen scavenging compounds may comprise polybutadiene or a residue of a polybutadiene (herein referred to collectively as “polybutadiene-based compounds”) which may be included in a copolymer, for example as described in embodiments Al or A2. In this case, the oxygen scavenging composition (Composition IV) may include:

[0237] (i) one or more polybutadiene-based compounds, wherein the sum of the wt% of polybutadiene-based compounds in the composition is in the range 50 to 99 wt%, preferably in the range 80 to 99 wt%; and

[0238] (ii) 0.009 wt% to 1.00 wt%, preferably 0.09 wt% to 1.00 wt%, of transition metal catalyst.

[0239] Each of the aforementioned compositions I to IV may include 0.09 to 15.0 wt%, for example, 0.90 to 10.0 wt%, of a transition metal catalyst compound, for example, a cobalt compound such as cobalt stearate.

[0240] In exemplary embodiments, the oxygen scavenging composition may comprise at least some oxygen scavenging compound which is an ethylenically-unsaturated compound, for example polybutadiene, which is not covalently bonded to another polymer (such as polymer XI and / or any polyester) to define a copolymer. In this case, the oxygen scavenging composition may include at least 20 wt%, or at least 30 wt%, or at least 40 wt% of an oxygen scavenging compound which is an ethylenically-unsaturated compound, for example polybutadiene, which is not copolymerised with polymer XI and / or any polyester. In some cases, the oxygen scavenging composition may include at least 70 wt%, or at least 80 wt%, or at least 90 wt%, of an oxygen scavenging compound which is an ethylenically-unsaturated compound, for example, polybutadiene, which is not copolymerised with polymer XI and / or any polyester. The balance of such an oxygen scavenging composition may include polyester and / or catalyst compound.

[0241] In embodiments, the oxygen scavenging composition may comprise 30 to 98 wt%, 40 to 98 wt%, 50 to 98 wt%, or 80 to 98 wt%, of polybutadiene which is not covalently bonded to another polymer (such as polymer XI and / or any polyester) to define a copolymer; 0.09 to 15.0 wt%, for example, 0.90 to 10.0 wt%, of a transition metal catalyst compound as described; and 0 to 60 wt% polyester, for example PET.

[0242] Oxygen scavenging compositions as described may be capable of relatively high oxygen uptake. For example, in the test referred to in example 4 hereinafter, the oxygen uptake may be at least 1 cc per gram of the composition. The uptake may be at least 5 or at least 10 cc per gram of the composition.

[0243] Method of Protecting Wafers

[0244] According to an aspect of the invention, a method of protecting one or more semiconductor wafers from contamination by oxygen and / or moisture is provided. The methodcomprises steps of (i) selecting a wafer carrier as described in the first aspect; and (ii) arranging wafers to be protected within an interior space of a wafer carrier housing of the wafer carrier.

[0245] The method may comprise releasably securing a scavenging device as described herein relative to the wafer carrier housing. The method may comprise after a period of time for example after the scavenging ability of the scavenging device has reduced to less than a predetermined level, removing the scavenging device from its association with the wafer carrier housing and / or disengaging the scavenging device from the wafer carrier. The scavenging device may then be refilled with scavenger compound and / or scavenger composition and the scavenging device reassembled and / or re engaged with the wafer carrier or a new scavenging device may be engaged with the wafer carrier, for example associated with the wafer carrier housing.

[0246] In embodiments, the method may extend to protecting one or more semiconductor wafers from contamination by moisture and contamination by oxygen.

[0247] Use for Protecting Wafers

[0248] According to an aspect of the invention, use of a wafer carrier as described according to the first aspect for protecting one or more semiconductor wafers from contamination by moisture is provided.

[0249] In embodiments, the use may extend to protecting one or more semiconductor wafers from contamination by moisture and contamination by oxygen.

[0250] Novel Scavenging Device

[0251] According to an aspect of the invention, a novel scavenging device for cooperation with a wafer carrier housing of a wafer carrier is provided, the scavenging device having any feature of the scavenging device as described in the first aspect.

[0252] The scavenging device may have any feature or combination of features as described for the scavenging device of the first aspect. A wafer carrier, for example, a FOUP, may be arranged to cooperate with a scavenging device of a type herein described.

[0253] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings, FIGS. 1 to 27. In the drawings, the same or similar parts may be annotated with the same reference numerals.

[0254] Exemplary Embodiment A

[0255] Referring to FIGS. 1 to 3, a scavenging device 2 comprises a pouch 4 which is filled with a loose fill of powder / pellets of a scavenging material 6. After filling, illustrated in FIG. 1, the pouch 4 is sealed along its upper edge 8 which incorporates die-cut holes 10 via which the pouch may be hung from corresponding fixings arranged on an inside of a door 12 of a FOUP 14 (FIG. 3). FIG. 3 shows two scavenging devices 2 positioned at opposing sides of the door 12.

[0256] Pouch 4 is made from a permeable material for example HDPE and is thereby arranged so that oxygen and / or moisture can permeate walls of the pouch and contact scavenging material 6 which thereby scavenges the oxygen and / or moisture.

[0257] In a FOUP which includes two scavenging devices as shown in FIG. 3, both devices 2 may be arranged to scavenge oxygen; or both devices 2 may be arranged to scavenge moisture; or both devices 2 may be arranged to scavenge both oxygen and moisture by mixing oxygen scavenger and moisture scavenger; or one device 2 may be arranged to scavenge oxygen and the other arranged to scavenge moisture.

[0258] After the scavenging ability of scavenging material 6 in a device 2 has been exhausted, the complete device 2 may be replaced; or the pouch 4 of the device may be refilled with active scavenging material 6.

[0259] Exemplary Embodiment B

[0260] Referring to FIGS. 4 to 8, refill 24 comprises a semipermeable outer wall which encloses and retains powder / pellets of a scavenging material 6. The refill 24 is arranged so that oxygen and / or moisture can permeate the refill and contact scavenging material 6 which thereby scavenges any oxygen and / or moisture which may be within FOUP 14. A molded frame 20 releasably engages the refill 24 to provide the complete device 22. The molded frame 20 includes lugs 26 for releasably securing the complete device 22 to an inside surface of a door 12 of a FOUP 14.

[0261] Exemplary Embodiment C

[0262] Referring to FIGS. 9 to 12, a scavenging device 30 comprises a molded polypropylene framework 32 which supports permeable mesh panels 34a to 34d. Referring to FIG. 9, the framework includes a base panel 34b to which respective side panels 34a and 34d are pivotably mounted. Panels 34a, 34b and 34d are arranged to be pivoted to define a triangular section which can be closed by a pivotable top panel 34d and bottom panel (not shown), thereby to define the arrangement of FIG. 11. The device 30 may be filled with loose fill scavenging material 6 as illustrated in FIG. 10, prior to pivoting top panel 34d to its closed position. Two scavenging devices 30 may be mounted on the inside of a door 12 of a FOUP (FIG. 12).

[0263] The permeable mesh panels 34 of the device 30 may be made from HDPE and thereby arranged so that oxygen and / or moisture can permeate the panels and contact scavenging material 6 which thereby scavenges the oxygen and / or moisture as described herein.

[0264] Exemplary Embodiment D

[0265] Referring to FIGS. 13 to 16, a scavenging device 40 includes a polypropylene frame 42. The frame 42 includes a planar back 44 to which a closure 46 is pivotably mounted along pivot axis 48. The closure 46 includes four openings 50. A scavenging packet 52 is arranged to be positioned on the base 44 and secured in position by moving the closure 46 about pivot axis 48 to a closed position in which it lies parallel to the base 44 as shown in FIG. 15.

[0266] The scavenging packet may be made from HDPE and defines a receptacle in which scavenging material is arranged. The receptacle is arranged to be permeable, so that oxygen and / or moisture can permeate the receptacle and contact the scavenging material which can then scavenge any oxygen and / or moisture.

[0267] A rear planar face 54 (FIG. 16) of the frame 42 is provided with an adhesive backing 56 for securing the device 40 to a planar region on the inside of a door of a FOUP. Advantageously, the device 40 may be secured to a conventional FOUP without the need to modify the FOUP by incorporation of fixing elements (or the like).

[0268] A FOUP may be provided with a multiplicity of scavenging devices 40 as described.

[0269] Exemplary Embodiment E

[0270] Referring to FIGS. 17 to 18, a scavenging device comprises a duct assembly 60 and mounting devices 62 which are arranged to cooperate with a modified FOUP 64.

[0271] The FOUP 64 includes openings 66 on opposite sides of the FOUP (only the right-hand side one being shown in FIG. 17) providing access into the interior space of the FOUP. Openings 66 are arranged to sealingly engage corresponding respective mounting rings 62. Each ring 62 includes a frame 67 which supports a membrane 68 which is permeable to oxygen and / or moisture.

[0272] Each frame 67 includes a circumferential, stepped region which is arranged to releasably engage inwardly facing, recessed regions 70 defined at respective ends of the duct assembly 60.

[0273] The duct assembly 60 may be made from semiconductor grade high purity polymers such as polycarbonate, COP, PP or PE (or any other material which may be used in a FOUP body). The duct assembly 60 is hollow and contains scavenging material (not shown) which is in fluid communication with the outside via the recessed regions 70.

[0274] In use, mounting devices 62 are engaged within respective openings 66 and the duct assembly 60 is snap-fitted in position around part of wall 72 of the FOUP. When so arranged, oxygen and / or moisture can travel from an interior space of the FOUP into duct assembly 60 via openings 66, membrane 68 and recessed regions 70, where it can be scavenged by the scavenging material contained within the duct assembly 60. The duct assembly may be disengaged and replaced as necessary when the scavenging ability of the scavenging material in the duct assembly 60 is diminished.

[0275] Exemplary Embodiment F

[0276] Referring to FIG. 19, a FOUP 80 includes a circular collar 82 in a side wall, within which a grid of openings 84 are defined to provide access from outside the FOUP to its inside space. A circular cross-section puck 86 which comprises scavenging material is arranged to be engaged within the collar 82 and secured in position by an end cap 88 which is arranged to releasably, screw-threadedly engage the collar. On an opposite side of the FOUP there is provided a puck 90 and end cap 92 which are identical to puck 86 and end cap 88 and arranged to be securedwithin a circular collar (not shown) defined in the opposite side of the FOUP and which is identical to collar 82. The end caps 88, 92 may be made from semiconductor grade high purity polymers such as polycarbonate, COP, PP or PE (or any other material which may be used in a FOUP body).

[0277] The pucks 86, 90 may comprise compositions which include scavenging material. Alternatively pucks 86, 90 may include a flexible or rigid receptacle having scavenging material to restrict and / or prevent passage of the scavenging compound into the interior space, however, is preferably permeable to oxygen and / or moisture.

[0278] Exemplary Embodiment G

[0279] Referring to FIG. 20, a rear wall 100 of a FOUP includes a window 102 which is arranged to releasably engage a scavenging device which comprises an outer molded housing part 104 and an inner molded housing part 106. The inner and outer housing parts 104, 106 are arranged to encapsulate a scavenging slab 108 and cooperate to releasably secure the scavenging device within window 102.

[0280] The slab 108 comprises a composition which includes a scavenging material.

[0281] The outer housing part 104 is substantially impermeable and the inner housing part 106 includes a permeable region which is arranged to allow passage of oxygen and / or moisture from the interior space of the FOUP towards and into the scavenging slab 108 where the oxygen and / or moisture can be scavenged.

[0282] Referring to FIG. 21, a rear wall of FOUP having a space 122 incorporating an outer molded housing part 104, an inner molded housing part 106 and a scavenging slab 108 which is arranged to allow fluid communication between an inside space of the FOUP and the scavenging material.

[0283] Exemplary Embodiment H-l

[0284] Referring to FIGS. 22 to 24, a FOUP 140 includes a pair 142, 144 of combined scavenging devices and nitrogen diffusers. Each member of the pair 142, 144 includes a nitrogen diffuser component 146 and a scavenging device component 148. Each nitrogen diffusercomponent 146 includes a chamber which is arranged to cooperate with a supply of nitrogen which is arranged to be delivered into the interior space of the FOUP to purge the FOUP of unwanted fluid. Each scavenging device component 148 includes a chamber containing scavenging material, wherein the arrangement is such that gaseous fluid (e g. oxygen and / or moisture) may pass from an inside space of the FOUP into the scavenging material, where the gaseous fluid can be scavenged. The scavenging material may be a component of compositions which include scavenging material and may comprise a solid mass or a puck as described for pucks 86, 90.

[0285] Each pair defining a combined scavenging device and nitrogen diffuser may be made as a unitary injection molding. The combination includes separate passages for flow of nitrogen into the FOUP on the one hand and for passage of oxygen and / moisture from the FOUP to the scavenging material in component 148 on the other hand.

[0286] Exemplary Embodiment H-2

[0287] Referring to FIGS. 25 to 27, a FOUP 160 includes spaced apart nitrogen diffusers 162 to which respective scavenging devices 164 have been retrofitted by releasably securable straps 166. Each scavenging device includes a chamber containing scavenging material which may be provided within a solid mass or a puck as described for pucks 86, 90. The arrangement of cooperating scavenging devices and nitrogen diffusers is suitably such that gaseous fluid (eg oxygen and / or moisture) may pass from an inside space of the FOUP into the chambers of the scavenging devices, wherein the gaseous fluid can be scavenged. With the arrangement, the scavenging devices 164 may readily be replaced or replenished with scavenging material when required, by disengagement of straps 166. The nitrogen diffusers 162 may be supplied with nitrogen as required to purge the interior space of the FOUP.

[0288] Advantageously, with the arrangement of FIGS. 25 to 27, the scavenging devices can be retrofitted to existing nitrogen diffusers of FOUPs and readily replaced or replenished when required.

[0289] Every document cited herein is incorporated herein by reference in its entirety unless otherwise specified. The citation of any document is not to be construed as an admission that it is prior art with respect to any invention disclosed or claimed herein. To the extent that any meaningor definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0290] The invention is not restricted to the details of the foregoing embodiment(s). It will be apparent that modifications and variations are possible without departing from the scope of the disclosure defined in the appended claims. Although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects. The invention extends to any novel one, or any novel combination, of the features disclosed herein (including this specification and any accompanying claims, abstract, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. A wafer carrier comprising:(a) a wafer carrier housing having an interior space; and(b) a scavenging device with a scavenging compound in fluid communication with the interior space.

2. The wafer carrier according to claim 1 , wherein at least one semiconductor wafer is present within the interior space.

3. The wafer carrier according to claim 1 or claim 2, wherein the scavenging device comprises a retaining component which retains the scavenging compound within a predetermined volume, wherein the retaining component restricts and / or prevents passage of the scavenging compound outside of the scavenging device.

4. A wafer carrier according to any preceding claim, wherein the scavenging device comprises a retaining component which retains the scavenging compound within a predetermined volume, wherein the retaining component (a) comprises a receptacle which contains the scavenging compound, and / or (b) is defined by a polymeric material and the scavenging compound is embedded with the polymeric material, wherein the scavenging compound together with the polymeric material form a solid mass.

5. The wafer carrier according to claim 3 or claim 4, wherein the scavenging device and / or the retaining component comprises a barrier positioned between the interior space and the scavenging compound.

6. The wafer carrier according to claim 5, wherein the barrier (a) restricts and / or prevents passage of the scavenging compound outside of the scavenging device and into the interior space, and (b) is permeable to oxygen and / or moisture such that oxygen and / or moisture passes from the interior space to the scavenging compound.

7. The wafer carrier according to any preceding claim, wherein the scavenging compound is (a) in a form of particles having a particle size of least 2 pm, for example, in a range from 2 to 1000 pm; and / or (b) in a form of pellets or granules having a largest dimension of at least 1 mm, for example, in a range from 1 to 10 mm.

8. The wafer carrier according to any preceding claim, wherein the scavenging device and / or the retaining component is releasably secured to the wafer carrier housing.

9. The wafer carrier according to any preceding claim, wherein the scavenging device is positioned within the interior space.

10. The wafer carrier according to claim 9, wherein the scavenging device comprises a first securement element for releasably securing the scavenging device at a position within the interior space, and wherein:(a) the first securement element cooperates with a second securement element positioned within the interior space to releasably secure the scavenging device at the position; or(b) the first securement element has a face, optionally comprising an adhesive area, for contacting an area within the interior space to releasably secure the scavenging device at the position.

11. The wafer carrier according to claim 9 or claim 10, wherein the scavenging device comprises a flexible receptacle, for example, a pouch, which acts as the retaining component and comprises a barrier to restrict and / or prevent passage of the scavenging compound outside of the scavenging device and into the interior space.

12. The wafer carrier according to claim 9 or claim 10, wherein the scavenging device comprises a frame which is arranged to releasably engage a permeable refill unit, which acts as the retaining component and comprises a barrier to restrict and / or prevent passage of the scavenging compound outside of the scavenging device and into the interior space.

13. The wafer carrier according to claim 9 or claim 10, wherein the scavenging device comprises a set of cooperable panels, each cooperable panel comprising a substantially rigid framework and at least one permeable region, wherein the set of cooperable panels is arranged to define a hollow receptacle, which acts as the retaining component and comprises a barrier to restrict and / or prevent passage of the scavenging compound outside of the scavenging device and into the interior space.

14. The wafer carrier according to claim 9 or claim 10, wherein the scavenging device comprises a scavenger housing arranged to releasably engage a flexible receptacle, for example, a pouch, which acts as the retaining component and comprises a barrier to restrict and / or prevent passage of the scavenging compound outside of the scavenging device and into the interior space.

15. The wafer carrier according to claim 9, wherein the wafer carrier comprises a nitrogen diffuser and the scavenging device is associated with the nitrogen diffuser.

16. The wafer carrier according to claim 15, wherein the nitrogen diffuser is positioned within the wafer carrier housing and comprises a nitrogen chamber which is arranged to fluidly communicate with a supply of nitrogen and deliver the nitrogen into the interior space of the wafer carrier housing; and wherein the scavenging device comprises a scavenging chamber which contains the scavenging compound and is in fluid communication with the interior space of the wafer carrier housing.

17. The wafer carrier according to claim 16, wherein the wafer carrier comprises a first passage separate from a second passage, wherein the first passage is for flow of nitrogen from the nitrogen supply to the interior space and the second passage is for flow of oxygen and / moisture from the interior space to the scavenging compound.

18. The wafer carrier according to any one of claims 1 to 8, wherein the scavenging device is positioned outside the interior space.

19. The wafer carrier according to claim 18, wherein the scavenging device comprises a scavenger housing arranged on the outside of the wafer carrier housing, wherein the scavenging compound is contained within the scavenger housing; and, optionally, wherein the scavenging compound is in a form of particles, and wherein the particles are free-flowing within the scavenger housing but are restricted from passing from within the scavenger housing and into the interior space.

20. The wafer carrier according to claim 18 or claim 19, wherein the scavenging device comprises a solid body which contains the scavenging compound, wherein the solid body is positioned outside the interior space and is releasably secured to an opening in a wall of the wafer carrier housing, wherein a porous member is positioned in the opening and between the interior space and the solid body, and, optionally, wherein the solid body has a thickness C and a maximum dimension D, wherein a ratio of dimension D divided by thickness C is at least 5 and less than 100 or less than 50.

21. The wafer carrier according to any one of claims 18 to 20, wherein the scavenging device is releasably secured to an opening in a wall of the wafer carrier housing and comprises a solid body which contains the scavenging compound, the solid body being a component of a scavenging assembly which comprises first and second housing parts arranged with the solid body positioned between them.

22. The wafer carrier according to any preceding claim, wherein the scavenging compound is a moisture scavenging compound and / or is a component of a moisture scavenging composition; and / or the scavenging compound is an oxygen scavenging compound and / or is a component of an oxygen scavenging composition.

23. A method of protecting a semiconductor wafer from contamination by oxygen and / or moisture, the method comprising the steps of (i) providing the wafer carrier according to any preceding claim; and (ii) arranging the semiconductor wafer within the interior space.

24. Use of the wafer carrier according to any one of claims 1 to 22 for protecting a semiconductor wafer from contamination by oxygen and / or moisture.

25. A scavenging device for cooperation with a wafer carrier, wherein the scavenging device comprises one or more features as disclosed herein.

26. The scavenging device according to claim 25, wherein the scavenging device comprises one or more features as shown in any of:(a) FIGS. I to 3;(b) FIGS. 4 to 8;(c) FIGS. 9 to 12;(d) FIGS. 13 to 16;(e) FIGS. 17 to 18;(f) FIG. 19;(g) FIGS. 20 to 21;(h) FIGS. 22 to 24; and / or(i) FIGS. 25 to 27.

Images