Membrane diffuser for substrate container

Abstract

The present invention relates to a purge diffuser in a system for transporting substrates, comprising: i) a purge diffuser core having an internal purge gas passage, one or more diffuser ports and an outer surface; ii) a filter medium fixed to the outer surface of the purge diffuser core; iii) a purge port connector for mounting the purge diffuser to a purge port of a substrate container for transporting substrates. The purge diffuser core may be a single piece, may be formed by injection molding, and may include a diverter within the internal purge gas passage.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 723,979, filed on August 28, 2018, U.S. Provisional Application No. 62 / 837,389, filed on April 23, 2019, and U.S. Provisional Application No. 62 / 874,647, filed on July 16, 2019, all of which are incorporated herein by reference in their entirety for all purposes. Technical Field

[0003] The present invention relates to a system for transporting or storing substrates, comprising a container and a system for purifying the environment within the container to desired levels of relative humidity, oxygen, and aerosol particles. Background Art

[0004] In general, specialized carriers or containers are utilized to transport and / or store batches of silicon wafers or substrates before, during, and after processing the wafers or substrates. As used herein, the term substrate may refer to one or more of semiconductor wafers, disks, flat panel substrates, and other such substrates.

[0005] Such containers are generally configured to place substrates axially in the slots and to support the substrates in the slots by or near their peripheral edges. The substrates can be removed from the container, typically in a radial direction, upwardly or laterally. Exemplary containers for transporting wafers or substrates may include a front opening unpacking pod (FOUP) or a front opening ship box (FOSB). In certain configurations, the container portion of the substrate carrier has openings or passages to facilitate the introduction and / or exhaust of gases, such as nitrogen or other purge gases, into the interior environment of the carrier to displace ambient air that may contain contaminants.

[0006] The presence or generation of particles during the processing of semiconductor substrates or wafers presents a significant contamination problem. Contamination is considered the single largest cause of yield loss in the semiconductor industry. As the size of integrated circuits continues to decrease, the size of particles that can contaminate the integrated circuits also decreases making it more critical to minimize contamination.

[0007] Currently, in order to create a clean space for accommodating substrates during transportation or storage, an inert gas or clean dry air (CDA) is used to purge the internal environment of the carrier, which is injected into the interior of the container through an inlet to cause the air in the container to leave through an outlet. These purge gas inlets and outlets are generally located on the bottom surface of the container body or shell and extend from the inside through the bottom surface of the shell where the purge gas inlet and outlet are interfaced with the purge gas delivery system. The goal of purification is to reduce the humidity and oxygen levels in the internal volume of the microenvironment. The challenge of purification is to quickly and effectively distribute the purge gas evenly on the substrate in the container. Another goal of purification is to remove airborne contaminants from the environment in the container. However, these contaminants may be trapped in the filtering mechanism of the purification system itself to cause cross contamination and require additional cleaning.

[0008] Therefore, there is a need for an improved purification method and apparatus that solves the problem of evacuating a wafer container in a fast and efficient manner while controlling the relative humidity and oxygen concentration of the wafer container's internal environment. Additionally, there is a need for a purification method and apparatus that can allow high flow rates of purge gas at low pressure differentials while minimizing the purge system's inherent preference for entrained contaminants. Summary of the invention

[0009] Briefly, the present invention provides a purge diffuser for use in a system for transporting substrates and a system including such a purge diffuser. According to various embodiments described herein, the present invention provides a purge diffuser that minimizes particulate contamination while controlling relative humidity and oxygen concentration within the internal environment of a container containing such a purge diffuser. In addition, the purge diffuser is capable of controlling the back pressure in the system so as not to lose the static sealing interface with the static purge source during high flow rates of inert gas while achieving greater than 99% particle filtration efficiency.

[0010] A purge diffuser according to the present invention generally comprises: i) a purge diffuser core having an internal purge gas passage, one or more diffuser ports, and an outer surface; ii) a filter medium secured to the outer surface of the purge diffuser core; and iii) a purge port connector for mounting the purge diffuser to a purge port of a substrate container for transporting substrates. These elements are arranged so that purge gas entering through the purge port connector enters the internal purge gas passage, exits the internal purge gas passage through the diffuser port, and passes through the filter medium to the interior of the substrate container. In some embodiments, the purge diffuser core is a monolithic article of integral construction, and in some cases is made of an injection moldable, melt processable polymer in a single molding. In various non-limiting embodiments, the filter media may be directly bonded to the outer surface of the purifying diffuser core, for example, by a welded bond, secured to the outer surface of the purifying diffuser core by an adhesive, or secured to the outer surface of the purifying diffuser core by a filter media holder, in which case the filter media is secured between the purifying diffuser core and the filter media holder and the filter media holder is attached to the purifying diffuser core. This filter media holder may be attached to the purifying diffuser core by welding, friction fit, adhesive, fasteners, or other mechanisms. In certain embodiments, the filter media may include a mesh scrim disposed or wrapped on the outer surface of the filter media to protect the filter media.

[0011] According to various embodiments, the filter medium is a porous hydrophobic film or membrane comprising a polyolefin, polyester, polysulfone or fluoropolymer, and may have a thickness between 10 microns and 1300 microns, between 10 microns and 1000 microns, between 10 microns and 500 microns, or between 40 microns and 150 microns. In some embodiments, the filter medium is a porous hydrophobic membrane, and in certain embodiments, the filter medium is a hydrophobic ultra-high molecular weight polyethylene (UPE) membrane. In many cases, the membrane or film is preferably non-pleated and is a non-pleated membrane or film. The membrane or film can be used to achieve screening of contaminants or not, depending on the potential contaminants.

[0012] According to various embodiments, the purge diffuser core includes a plurality of diffuser ports. Purge gas exits the internal purge gas passage through the diffuser ports and enters the interior of the substrate container through the filter media disposed on or wrapped around the purge diffuser core.

[0013] In some embodiments, the purge diffuser core further comprises one or more diverters protruding into the internal purge gas passage from an inner surface of the purge diffuser core bordering the internal purge gas passage. In some embodiments, the diverters are staggered to enable the purge diffuser core to be injection molded as a single piece in a single molding.

[0014] In other embodiments, the present invention provides a system comprising: a purge diffuser according to the present invention; and a substrate container comprising a container portion having an opening, a door adapted to be received in the opening to seal the interior environment of the substrate container, and a purge port for permitting purge gas to reach the interior of the substrate container. The purge diffuser is mounted to the purge port by its purge port connector. In some embodiments, the substrate container is a front opening pod (FOUP).

[0015] In another embodiment, the present invention provides a method of manufacturing a purifying diffuser according to the present invention, comprising: a) molding the purifying diffuser core as a single unitary object; and b) securing a filter medium to the outer surface of the purifying diffuser core. In some embodiments, molding the purifying diffuser core as a single unitary object is accomplished by injection molding. In some embodiments, securing the filter medium to the outer surface of the purifying diffuser core is accomplished by a welding method such as pulse welding.

[0016] In yet another embodiment, the present invention provides a method of purging a system for transporting substrates according to the present invention, comprising passing a purge gas flow through the purge port into the purge diffuser and thereby into the interior of the substrate container. In some embodiments, the purge gas is nitrogen and the purge diffuser provides a greater purge gas flow to a lower portion of the interior of the substrate container than to a higher portion of the interior of the substrate container.

[0017] The above summary of the invention does not intend to describe every embodiment of the invention. The details of one or more embodiments of the invention will also be set forth in the following description. Other features, purposes and advantages of the invention will be apparent from the description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The invention may be more fully understood in view of the following description of various illustrative embodiments taken in conjunction with the accompanying drawings.

[0019] Figure 1 is a perspective view of an embodiment of a system for transporting substrates according to the present invention.

[0020] Figure 2 is a perspective view of an embodiment of a purification diffuser core according to the present invention.

[0021] Figure 3 yes Figure 2 A cross-sectional view of a purification diffuser core.

[0022] Figure 4 is a perspective view of an embodiment of a purification diffuser core according to the present invention.

[0023] Figure 5 is incorporated Figure 4 A perspective view of an embodiment of a purification diffuser according to the present invention of a purification diffuser core.

[0024] Fig. 6A and 6B yes Figure 4 A perspective view of a detail of an embodiment of a purification diffuser core.

[0025] Fig. 7A is a perspective view of a purification diffuser according to an embodiment of the present invention.

[0026] Figure 7B yes Fig. 7A Exploded view of the purifying diffuser.

[0027] Figure 8 is a graph illustrating the open-door relative humidity performance of a purification diffuser according to an embodiment of the present invention.

[0028] Although the present invention is susceptible to various modifications and alternative forms, its specific forms have been shown in the drawings by way of example and will be described in detail. However, it should be understood that it is not desirable to limit the aspects of the present invention to the specific illustrative embodiments described. On the contrary, it is desirable to cover all modifications, equivalents and substitutions that fall within the spirit and scope of the present invention. DETAILED DESCRIPTION

[0029] As used in this specification and the following claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the following claims, the term "or" is generally used to mean "and / or" unless the content clearly dictates otherwise.

[0030] As used herein, "having," "comprising," "including," or the like are intended to be open ended and generally mean "including, but not limited to." It should be understood that the terms "consisting of" and "consisting essentially of" are subsumed within the terms "comprising" and the like.

[0031] The term "about" generally refers to a range of values ​​that are considered equivalent to the recited value (eg, having the same function or result). In many cases, the term "about" may include values ​​that are rounded to the nearest significant figure.

[0032] The term "directly bonded" refers to two materials that are in direct contact with each other and bonded together.

[0033] The terms "integrated" or "integrated construction" refer to a single-piece construction, but it may include individually nameable elements, may be a single item, or may be formed from multiple pieces where the multiple pieces are permanently joined (e.g., by welding, permanent adhesives, permanent fasteners, or methods that cannot be non-destructively reversed) to form the single-piece construction.

[0034] The terms "monolithic" or "monolithic article" refer to a single-piece article, although it may include separately nameable elements, formed from a single piece or integral part of material without dividing the piece or integral part (e.g., by stamping, molding, forging, machining, sculpting, or the like), and without seams or joints between the elements.

[0035] The use of numerical ranges using endpoints includes all numbers subsumed within that range (eg 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0036] Unless defined otherwise, all technical and scientific terms used herein have the meanings commonly used in the art.

[0037] The following detailed description should be read with reference to the drawings, in which similar elements in different drawings are numbered the same. The detailed description and the accompanying drawings (which are not necessarily drawn to scale) depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended to be exemplary only. Unless expressly stated to the contrary, selected features of any illustrative embodiment may be incorporated into additional embodiments.

[0038] The present invention provides a purge diffuser in a system for transporting substrates and a system including such a purge diffuser. Such a system typically includes a substrate container, which includes: a container portion, which includes a top wall, a bottom wall, a rear wall and two side walls defining an opening; a door, which is adapted to be received in the opening to seal the internal environment; and a purge port, which allows purge gas to reach the interior of the substrate container. Some such substrate containers are typically referred to as FOUPs or FOSBs. Substrates can typically be inserted and removed horizontally through a front opening. Slots formed in the inner side hold substrates, most commonly semiconductor wafers. The door is joined to the housing to form a sealed internal space isolated from the ambient atmosphere. Typically, the door and substrate container are adapted to be manipulated by an automatic or robotic mechanism. Similarly, a substrate can be placed into or removed from the substrate container by an automatic or robotic mechanism. The purge port can be located in the bottom wall (or bottom plate) of the housing portion and typically includes hardware for mounting a purge port connector of the purge diffuser and forming a seal therewith.

[0039] According to various embodiments described herein, a purge diffuser is adapted to distribute purge gas in the interior of a substrate container. Purge gas is directed through a purge port and a purge port connector into a purge gas channel within the purge diffuser. Purge gas exits the internal purge gas channel through the diffuser port and enters the interior of the substrate container through a filter medium. The distribution of purge gas within the interior of the substrate container can be controlled by using a purge diffuser to avoid dead spots and achieve a desired distribution. Any suitable purge gas can be used, which can include clean dry air (CDA) and inert gases, such as nitrogen. The design of the purge diffuser can be adapted to the selected purge gas. For example, when using a gas that is lighter than air, such as nitrogen, more flow to the lower portion of the interior of the substrate container can result in a more uniform purge of the container and its contents from contaminants, particles, and moisture. In some embodiments, the substrate container may additionally include a purge outlet to allow purge gas to flow out of the container. In other cases, the container is purged when the door is removed and the purge gas exits through the opening before the container.

[0040] The purification diffuser according to the present invention includes a purification diffuser core having an internal purification gas channel and one or more diffuser ports to allow the purification gas to leave the internal purification gas channel to the outside of the purification diffuser core and enter the interior of the substrate container. The purification diffuser core may include features for attaching to a mounting device, typically at the end of the purification diffuser core opposite to the purification port connector. In some embodiments, the purification diffuser core is an integrated construction so that it is a single object. The purification diffuser core can be made of any suitable material, which can include injection moldable materials, melt-processable polymers, fluoropolymers, polyolefins, or fluorinated polyolefins. In some cases, the purification diffuser core can be made of carbon-filled materials to facilitate the elimination of electrostatic discharge. The purification diffuser core should be made of a material that minimizes the outgassing rate.

[0041] In some cases, the purge diffuser may be sized to minimize the mass of material of the purge diffuser within the interior environment of the substrate container. The mass of material in the substrate container may absorb exhaust (airborne molecular contamination (AMC)) from the wafer process, such as boron, ammonia, chlorine, or fluorine, and then desorb these contaminants back into the container environment to potentially cause wafer yield loss. Reducing the amount of material in the interior environment may improve the preference for AMC absorption and desorption. A method for reducing the mass of material within the interior environment of the wafer container is to reduce the overall length or height of the purge diffuser relative to the interior height of the substrate container and more specifically, relative to the interior height of the substrate measured from the top wall of the container portion to the bottom wall of the container portion of the substrate container. In some embodiments, the length or height of the purge diffuser does not exceed 85% of the height of the interior of the substrate container measured from the top wall of the container portion of the substrate container to the bottom wall, and in other embodiments, does not exceed 75%, 65%, 60%, 55%, 50%, 45%, or 40% of the height of the substrate container. In some such embodiments, the length or height of the purge diffuser is at least 20% of the interior height of the substrate container, in other embodiments, at least 25%, 30% or 35% of the interior height of the substrate container. In some cases, the purge diffuser may have a length ranging from 100 mm to 170 mm, from 105 mm to 160 mm, or from 110 mm to 150 mm. In a particular embodiment, the purge diffuser has a length of 150 mm. In another embodiment, the purge diffuser has a length of 110 mm. The total length of the purge diffuser measured relative to the height of the substrate container may be selected or optimized based on the intended application. For example, the length of the purge diffuser may be optimized based on the type of purge gas, the flow rate of the purge gas, and / or the acceptable level of relative humidity and oxygen in the environment of the container and / or the nature of the contaminants entrained by the purge diffuser (but not limited thereto). In some embodiments, a purge diffuser having a reduced height or length relative to the height of the substrate container may be used in combination with other embodiments (as disclosed herein) for reducing contaminants within the interior environment of the container and / or for controlling relative humidity and oxygen levels.

[0042] The internal purge gas passage may have a length equal to or less than the length of the purge diffuser core. In some embodiments, the length of the internal gas passage is no more than 85% of the interior height of the substrate container, in other embodiments, no more than 75%, 65%, 60%, 55%, 50%, 45%, or 40%. In some such embodiments, the length of the internal gas passage is at least 20% of the interior height of the substrate container, in other embodiments, at least 25%, 30%, or 35%.

[0043] The purge diffuser may include a plurality of diffuser ports distributed along the length of the purge diffuser core. The purge gas exits the internal purge gas channel through the diffuser ports. In some cases, the purge gas exits the internal purge gas channel and enters the interior of the substrate container through a filter medium disposed or wrapped around the purge diffuser core. The diffuser ports may have any suitable shape, size, and position along the length of the purge diffuser core. The distribution and characteristics of the diffuser ports may be selected to achieve the desired distribution of the purge gas flow and be uniform or variable. In some embodiments, the rows of diffuser ports are offset from each other so that each portion of the internal purge gas channel between the diffuser port closest to the purge port connector and the diffuser port farthest from the purge port connector can be accessed by a diffuser port along a line perpendicular to the length of the purge diffuser. This design enables the purge diffuser core to be manufactured as a single piece with a continuous internal channel (internal purge gas channel) by a molding process (e.g., an injection molding process using side pull, jacking, cam action, or sliding).

[0044] In some embodiments, the purge diffuser core further includes a diverter that protrudes from the inner surface of the purge diffuser core (i.e., the inner surface of the purge diffuser core that interfaces with the inner purge gas channel) into the inner purge gas channel. The diverter may be any suitable shape (e.g., a fin or a peg), or may be bridged across the inner purge gas channel from a first position on the inner surface of the purge diffuser core to a second separate position on the inner surface of the purge diffuser core. The diverter may hinder, but generally does not prevent, the flow of purge gas to other parts of the inner purge gas channel. The distribution and characteristics of the diverter may be selected to achieve the desired distribution of the purge gas flow. The distribution and characteristics of the diverter may be uniform or variable along the length of the inner purge gas channel. In some embodiments, the diffuser core includes a diverter in a first section of the inner purge gas channel near the purge port and does not include a diverter in a second section of the inner purge gas channel away from the purge port.

[0045] The purge diffuser core may be manufactured by any suitable method. Typically, a hot melt molding method such as injection molding may be used. In some cases, as described herein, the purge diffuser core is injection molded to produce an integrally formed, one-piece object.

[0046] The purifying diffuser according to the present invention includes a filter medium disposed on and fixed to the outer surface of the purifying diffuser core. The filter medium may be presented in sections, or more typically, may be in the form of a single sheet wrapped around the circumference of the purifying diffuser core. In some embodiments, the filter medium is directly bonded to the outer surface of the purifying diffuser core, for example, by a welding bond including, but not limited to, a thermal welding bond, a pulse welding bond, and an ultrasonic welding bond. Welding or bonding the filter medium to the purifying diffuser core provides the desired feature of leak-proof bonding the filter medium to the purifying diffuser core without the use of adhesives or fasteners.

[0047] In other embodiments, the filter medium is fixed to the outer surface of the purification diffuser core by an adhesive. In other embodiments, the filter medium is fixed to the outer surface of the purification diffuser core by a filter medium holder, wherein the filter medium is fixed between the purification diffuser core and the filter medium holder and the filter medium holder is attached to the purification diffuser core. The filter medium holder can be attached to the purification diffuser core by welding, friction fit, adhesive, fastener or other suitable mechanism. After attachment, the filter medium is appropriately reduced by applying heat to produce a tighter fit with the purification diffuser core. Typically, the filter medium covers each diffuser port of the purification diffuser core. Typically, the filter medium is attached so that the purified gas leaving through the diffuser port cannot enter the interior of the substrate container without passing through the filter medium. In some embodiments, the filter medium may have a mesh scrim, which is placed on the filter medium to provide protection to the filter medium and allow safe disposal of the filter medium. The mesh scrim can be attached to the filter medium without an adhesive or fastener. In some cases, the mesh scrim can be wrapped around the outer surface of the filter medium. Alternatively, the mesh scrim can be pulse welded to the filter medium.

[0048] The filter medium can be any suitable material for controlling relative humidity and oxygen, and can additionally remove particulates from the airflow passing through the filter medium. In various embodiments, the filter medium can include woven, nonwoven, screened, non-screened, meltblown, core-sheath, film or membrane materials and can include polyolefins (including polypropylene, polyethylene, high-density polyethylene or ultra-high molecular weight polyethylene), polyesters, polysulfones, fluoropolymers, polyamides or polyimide polymers. The filter medium is preferably not pleated, so that it is a non-pleated filter medium. In some embodiments, the filter medium is a porous hydrophobic film. In other embodiments, the filter medium is a porous hydrophobic membrane. In an embodiment, the filter medium is a porous hydrophobic ultra-high molecular weight polyethylene membrane. The filter medium can be laser ablated to modify porosity. In some embodiments, the filter medium has a thickness between 10 microns and 1300 microns, between 10 microns and 1000 microns, between 10 microns and 500 microns, or between 40 microns and 150 microns.

[0049] In one aspect, the filter medium can be characterized relative to a property called "bubble point", which is a default property of a porous filter membrane. The bubble point corresponds to the pore size, which can correspond to the filter performance, such as measured by retention. Smaller pore sizes can be associated with higher bubble points and are generally associated with higher filter performance (higher retention). The membranes preferably used for the filter medium exhibit a combination of relatively high bubble points and effective flow levels (flow rates). Examples of effective average bubble points of membrane filter media can be in the range of from 2psi to 400psi, for example, in the range of from 5psi to 15psi. To measure the average bubble point, a sample of the filter medium is placed in a retainer. The air is pressurized by the retainer and the flow rate is measured as a function of pressure. Next, a low surface tension fluid HFE-7200 (3M) is introduced into the membrane to wet the membrane. The air is pressurized by passing through the retainer at the interior of the filter medium and the air flow is measured as a function of pressure. The average bubble point is the pressure when the ratio of the air flow of the wet membrane to the air flow of the dry membrane is 0.5. The tests were performed at temperatures ranging between 20 degrees Celsius and 25 degrees Celsius.

[0050] In some embodiments, exemplary membrane filtration media may have pores of a size (average pore size) to be considered as a microporous filter membrane or an ultrafiltration membrane. A microporous membrane may have an average pore size in the range of from about 0.05 microns to about 10 microns. An ultrafiltration membrane may have an average pore size in the range of from 0.001 microns to about 0.05 microns. The pore size is typically reported as the average pore size of a porous material that can be measured by known techniques such as mercury porosimetry (MP), scanning electron microscopy (SEM), liquid displacement (LLDP), or atomic force microscopy (AFM).

[0051] A purge diffuser according to the present invention typically includes a purge port connector for mounting the purge diffuser to a purge port of a substrate container. In some embodiments, the purge port connector is an integrated construction with the purge diffuser core, such that the purge core and the purge port connector form a single piece. In other embodiments, the purge port connector is a portion that is separate from the purge diffuser core but can be attached to the purge diffuser core. The purge port connector and the purge diffuser core are typically connected in a sealable manner so that purge gas cannot escape from the purge diffuser between the purge port connector and the purge diffuser core. The purge port connector can be made of any suitable material, including the materials listed above for the purge diffuser core.

[0052] refer to Figure 1, a system for transporting substrates according to an embodiment of the present invention includes a substrate container 190. A front edge 192 of the substrate container 190 surrounds a front opening and is adapted to receive a door (not shown), which is adapted to seal the opening defined by the front edge 192. Typically, the door (not shown) and the substrate container 190 are adapted to be manipulated by an automatic or robotic mechanism. The purification diffuser 110 is depicted without a filter media secured to the outer surface to reveal the purification diffuser core 120. According to an embodiment, the purification diffuser core 120 includes diffuser ports 130, 132 arranged in longitudinal rows. In Figure 1 In the depicted embodiment, the first row of diffuser ports 130 is offset from the second row of diffuser ports 132, wherein the center of the diffuser port 130 is substantially aligned with the boundary between the diffuser ports 132, and vice versa. The purification diffuser core 120 also includes an internal purge gas channel (not visible). A purge port connector 140 is attached to the bottom end of the purification diffuser core 120. The purge port connector 140 is mounted to the purge port (not visible because it is occupied and covered by the purge port connector 140). The purge port passes through the substrate container 190. During the purge of the substrate container 190, the purge gas enters the purge port connector 140 through the purge port and thereby enters the internal purge gas channel of the purification diffuser core 120. The purge gas then exits the internal purge gas channel through the diffuser ports 130, 132. When the filter media is mounted on the outer surface of the purification diffuser core 120, the purge gas that exits the internal purge gas channel through the diffuser ports 130, 132 passes through the filter media and enters the interior 194 of the substrate container 190. The substrate container 190 is also equipped with a substrate support 196 that defines a slot for storing a substrate (not shown) by or near its peripheral edge. Optional mounting hardware 180 can provide additional attachment of the purge diffuser 110 to the substrate container 190 as needed or desired.

[0053] refer to Figure 2 and 3 , which are perspective and cross-sectional views (respectively) of an embodiment of a purge diffuser core according to the present invention. The purge diffuser core 220 has its bottom end connected to a purge port connector 240. The purge port connector 240 is adapted to connect to a purge port of a substrate container. The purge diffuser core 220 includes an internal purge gas channel 260 that provides a path for the purge gas entering through the purge port to all of the diffuser ports 230, 232, 234 through the purge port connector 240. The purge diffuser core 220 includes diffuser ports 230, 232, 234 arranged in longitudinal rows. In some embodiments, as Figure 2 and 3, the diffuser port columns 230 are offset from the diffuser port rows 232, 234, wherein the center of the diffuser port 230 is generally aligned with the boundary between the diffuser ports 232, 234, and vice versa. When the diffuser ports 230, 232, 234 are staggered in this manner, each portion of the internal purge gas passage 260 between the diffuser port closest to the purge port connector and the diffuser port farthest from the purge port connector can be accessed by a diffuser port along a line perpendicular to the length of the purge diffuser. This design enables the purge diffuser core 220 to be manufactured as a single piece with a continuous internal passage (internal purge gas passage 260) through a molding process, such as an injection molding process using side pulling, jacking, camming, or sliding. The purge diffuser core 220 is adapted to engage with the mounting hardware assembly 280.

[0054] Additionally, the purge diffuser core 220 may optionally include a diverter 265 that protrudes from an inner surface of the purge diffuser core 220 bordering the inner purge gas channel 260 into the inner purge gas channel 260. The diverter 265 slows and / or directs the flow of the purge gas, but does not completely block the flow of the purge gas to another point along the inner purge gas channel 260. In this embodiment, the diverter 265 bridges across the inner purge gas channel 260 from a first location on the inner surface of the purge diffuser core 220 to a second and separate location on the inner surface of the purge diffuser core 220. In this embodiment, the purge diffuser core 220 includes the diverter 265 in a first section 266 of the inner purge gas channel 260 proximate the purge port connector 240, and does not include a diverter in a second section 267 of the inner purge gas channel 260 away from the purge port connector 240.

[0055] refer to Figure 4 and 5 , Figure 4 is a perspective view of an embodiment of a purification diffuser core according to the present invention. Figure 5 is incorporated Figure 44. A perspective view of an embodiment of a purge diffuser according to the present invention of a purge diffuser core. The purge diffuser 410 includes a purge diffuser core 420. The purge diffuser core 420 is connected at its bottom end to a purge port connector 440. The purge port connector 440 is adapted to connect to a purge port of a substrate container. The purge diffuser core 420 includes an internal purge gas channel (not visible) that provides a passage for the purge gas entering through the purge port to all diffuser ports 430, 432 through the purge port connector 440. The purge diffuser core 420 includes diffuser ports 430, 432 arranged in a longitudinal row. The diffuser port column 430 is offset from the diffuser port row 432, wherein the center of the diffuser port 430 is substantially aligned with the boundary between the diffuser ports 432, and vice versa. As mentioned above, when the diffuser ports 430, 432 are staggered in this manner, each portion of the internal purge gas passage between the diffuser port closest to the purge port connector and the diffuser port farthest from the purge port connector can be accessed through the diffuser port along a line perpendicular to the length of the purge diffuser. This design enables the purge diffuser core 420 to be manufactured as a single piece with continuous internal passages (internal purge gas passages) through a molding process (e.g., an injection molding process using side-pull, jacking, camming, or sliding).

[0056] refer to Fig. 6A and 6B , these pictures are Figure 4 4. A perspective view of the details of the purge diffuser core and its assembly. The purge diffuser core 420 has its bottom end connected to the purge port connector 440. Engagement tabs 442 securely attach the purge port connector 440 to the purge diffuser core 420. Seal 444 prevents purge gas from escaping at the interface between the purge port connector 440 and the purge diffuser core 420. Diffuser ports 430, 432 are shown.

[0057] Reference again Figure 5 , the filter medium 450 is fixed to the outer surface of the purification diffuser core 420, so that the purification gas from the purification port entering the purification diffuser 410 through the purification port connector 440 enters the internal purification gas channel, leaves the internal purification gas channel through the diffuser ports 430, 432, and enters the interior of the substrate container through the filter medium 450.

[0058] Fig. 7A is a perspective view of a purification diffuser 510 according to yet another embodiment and Figure 7B 5 is an exploded view thereof. The purification diffuser 510 comprises a porous membrane disposed on a purification diffuser core 520. Figure 4 and 5In the discussed embodiment, the purge diffuser core 520 has its bottom end connected to the purge port connector 540. The purge port connector 540 is adapted to connect to the purge port of the substrate container. The purge diffuser core 520 includes an internal purge gas channel (not visible) that provides a passage for the purge gas entering through the purge port to all the diffuser ports 530, 532 through the purge port connector 540. The purge diffuser core 520 includes diffuser ports 530, 532 arranged in a longitudinal row. The diffuser port rows 530 are offset from the diffuser port columns 532, wherein the center of the diffuser port 530 is generally aligned with the boundary between the diffuser ports 532, and vice versa. As mentioned above, when the diffuser ports 530, 532 are staggered in this manner, each portion of the internal purge gas channel between the diffuser port closest to the purge port connector and the diffuser port farthest from the purge port connector can be accessed by a diffuser port along a line perpendicular to the length of the purge diffuser. The filter medium 550 is fixed to the outer surface of the purge diffuser core 520 so that the purge gas from the purge port that enters the purge diffuser 510 through the purge port connector 540 enters the internal purge gas channel, exits the internal purge gas channel through the diffuser ports 530, 532, and enters the interior of the substrate container through the filter medium 550.

[0059] like Figure 7B , a mesh scrim 545 can be disposed on the filter medium 550 to provide protection to the filter medium 550 and allow for safe disposal of the filter medium 550. The mesh scrim can be attached to the filter medium without adhesives or fasteners. In some cases, the mesh scrim 545 can be wrapped around the outer surface of the filter medium 550. Alternatively, the mesh scrim 545 can be pulse welded to the filter medium 550.

[0060] As described herein, the filter media 450, 550 can be any suitable material for controlling relative humidity and oxygen, and can additionally remove particulates from the airflow passing through the filter media. In various embodiments, the filter media can include woven, nonwoven, screened, non-screened, meltblown, core-sheath, film or membrane materials and can include polyolefins (including polypropylene, polyethylene, high-density polyethylene or ultra-high molecular weight polyethylene), polyesters, polysulfones, fluoropolymers, polyamides or polyimide polymers. The filter media is preferably not pleated, so that it is a non-pleated filter media. In some embodiments, the filter media is a porous hydrophobic film. In other embodiments, the filter media is a porous hydrophobic membrane. In a preferred embodiment, the filter media is a porous hydrophobic ultra-high molecular weight polyethylene (UPE) membrane. In some cases, the UPE membrane is selected so that it provides a particle retention rate greater than 99% and a back pressure of less than 65kPa in the system.

[0061] Figure 8is a graph showing the open door relative humidity (RH%) performance of a purge diffuser including a UPE membrane according to an embodiment described herein. Relative humidity levels were measured using sensors positioned in front, left, right, and rear of the substrate container. The initial relative humidity level in the environment was 50% RH. Purge gas was introduced into the substrate container after the door was removed. The test was repeated for each of the 25 wafers contained in the substrate container. Figure 8 As shown in , the UPE membrane purge diffuser effectively minimizes the relative humidity level in the container environment at each wafer and each location during open door purge testing.

[0062] Selected Examples

[0063] The following numbered examples are intended to further illustrate the present invention but should not be construed as strictly limiting the present invention.

[0064] Embodiment 1. A system for transporting a substrate, comprising:

[0065] a) a substrate container comprising a container portion having an opening, a door adapted to seal the opening, and a purge port for admitting a purge gas to an interior of the substrate container; and

[0066] b) a purge diffuser mounted to the purge port, the purge diffuser comprising:

[0067] i) a purge diffuser core having an internal purge gas passage, one or more diffuser ports, and an outer surface; and

[0068] ii) a filter medium secured to the outer surface of the purifying diffuser core;

[0069] The system is arranged so that there is a continuous path for purge gas entering through the purge port to enter the internal purge gas passage, exit the internal purge gas passage through the diffuser port, and enter the interior of the substrate container through the filter media.

[0070] Embodiment 2. The system of embodiment 1, wherein the purge diffuser core is a single piece.

[0071] Embodiment 3. The system of Embodiment 1, wherein the purge diffuser core is a unitary piece comprising an injectable moldable material and manufactured in a single molding.

[0072] Embodiment 4. The system of embodiment 3, wherein the injection moldable material is a melt processable polymer.

[0073] Embodiment 5. The system of any of embodiments 1 to 4, wherein the filter media is directly bonded to the outer surface of the purge diffuser core.

[0074] Embodiment 6. The system of Embodiment 5, wherein the filter media is directly bonded to the outer surface of the purge diffuser core by a weld bond.

[0075] Embodiment 7. The system of Embodiment 5, wherein the filter media is directly bonded to the outer surface of the purge diffuser core by a weld bond selected from a thermal weld bond, a pulse weld bond, and an ultrasonic weld bond.

[0076] Embodiment 8. The system of any one of embodiments 1 to 4, wherein the filter media is secured to the outer surface of the purge diffuser core by an adhesive.

[0077] Embodiment 9. A system according to any one of embodiments 1 to 4, wherein the filter medium is fixed to the outer surface of the purification diffuser core by a filter medium holder, wherein the filter medium is fixed between the purification diffuser core and the filter medium holder and the filter medium holder is attached to the purification diffuser core.

[0078] Embodiment 10. The system of any one of embodiments 1 to 9, wherein the filter medium is a porous hydrophobic membrane comprising polyolefin, polyester, polysulfone, or fluoropolymer.

[0079] Embodiment 11. The system of any one of embodiments 1 to 9, wherein the filter medium is a hydrophobic ultra-high molecular weight polyethylene membrane.

[0080] Embodiment 12. A system according to any one of embodiments 1 to 11, wherein the purge port is included in a first wall of the substrate container, the first wall spanning the interior of the substrate container facing an opposite wall of the substrate container; wherein the minimum distance between the purge port and the opposite wall is the height of the interior of the substrate container; wherein the purge diffuser has a purge diffuser length, which is the distance the purge diffuser extends toward the opposite wall when installed to the purge port; and wherein the purge diffuser length does not exceed 85% of the height of the interior of the substrate container.

[0081] Embodiment 13. The system of Embodiment 12, wherein the purge diffuser length does not exceed 60% of the height of the interior of the substrate container.

[0082] Embodiment 14. The system of Embodiment 12 or 13, wherein the purge diffuser length is at least 20% of the height of the interior of the substrate container.

[0083] Embodiment 15. A system according to any one of embodiments 1 to 14, wherein the purge port is included in a first wall of the substrate container, the first wall spanning the interior of the substrate container facing an opposite wall of the substrate container; wherein the minimum distance between the purge port and the opposite wall is the height of the interior of the substrate container; wherein the internal purge gas channel has an internal purge gas channel length, which is the distance the internal purge gas channel extends toward the opposite wall when the purge diffuser is installed to the purge port; and wherein the internal purge gas channel length does not exceed 85% of the height of the interior of the substrate container.

[0084] Embodiment 16. The system of Embodiment 14, wherein the interior purge gas channel length does not exceed 60% of the height of the interior of the substrate container.

[0085] Embodiment 17. The system of Embodiment 14 or 15, wherein the interior purge gas channel length is at least 20% of the height of the interior of the substrate container.

[0086] Embodiment 18. A system according to any one of embodiments 1 to 17, wherein the purge diffuser core further includes one or more diverters, and the one or more diverters protrude from the inner surface of the purge diffuser core bordering the internal purge gas channel into the internal purge gas channel.

[0087] Embodiment 19. A system according to Embodiment 18, wherein one or more diverters bridge across the internal purge gas passage from a first position on the inner surface of the purge diffuser core to a second position on the inner surface of the purge diffuser core, the second position being separate from the first position.

[0088] Embodiment 20. A system according to Embodiment 17 or 19, wherein the diffuser core includes one or more diverters in a first section of the internal purge gas passage proximate to the purge port and includes no diverters in a second section of the internal purge gas passage away from the purge port.

[0089] Embodiment 21. A system according to Embodiment 20, wherein the first segment is smaller than the second segment.

[0090] Embodiment 22. A system according to any one of embodiments 1 to 21, wherein the diffuser ports are staggered so that each portion of the internal purge gas channel between the diffuser port closest to the purge port connector and the diffuser port farthest from the purge port connector can be accessed through a diffuser port along a line perpendicular to the length of the purge diffuser.

[0091] Embodiment 23. The system of any one of embodiments 1 to 22, wherein the substrate container is a front opening pod (FOUP).

[0092] Embodiment 24. The system of any one of embodiments 1 to 23, wherein the substrate is a semiconductor wafer.

[0093] Embodiment 25. A purge diffuser for use in a system for transporting a substrate, comprising:

[0094] i) a purge diffuser core having an internal purge gas passage, one or more diffuser ports, and an outer surface;

[0095] ii) a filter medium secured to the outer surface of the purification diffuser core; and

[0096] iii) a purge port connector for mounting the purge diffuser to a purge port of a substrate container for transporting substrates;

[0097] The purge diffuser is arranged so that there is a continuous path for purge gas entering through the purge port connector to enter the internal purge gas passage, exit the internal purge gas passage through the diffuser port, and pass through the filter media.

[0098] Embodiment 26. A purification diffuser according to embodiment 25, wherein the purification diffuser core is an integrated construction.

[0099] Embodiment 27. The purge diffuser of embodiment 25, wherein the purge diffuser core is a single piece.

[0100] Embodiment 28. The purge diffuser of any one of embodiments 24 to 27, wherein the purge diffuser core is a unitary piece comprising an injection moldable material and manufactured in a single molding.

[0101] Embodiment 29. The purge diffuser of embodiment 28, wherein the injection moldable material is a melt processable polymer.

[0102] Embodiment 30. The purifying diffuser of any one of embodiments 25 to 29, wherein the filter media is directly bonded to the outer surface of the purifying diffuser core.

[0103] Embodiment 31. The purifying diffuser of any one of embodiments 25 to 29, wherein the filter media is directly bonded to the outer surface of the purifying diffuser core by a weld bond.

[0104] Embodiment 32. The purification diffuser of embodiment 31, wherein the filter media is directly bonded to the outer surface of the purification diffuser core by a welding bond selected from a thermal welding bond, an impulse welding bond, and an ultrasonic welding bond.

[0105] Embodiment 33. The purification diffuser of any one of embodiments 25 to 29, wherein the filter medium is secured to the outer surface of the purification diffuser core by an adhesive.

[0106] Embodiment 34. A purification diffuser according to any one of embodiments 25 to 29, wherein the filter medium is fixed to the outer surface of the purification diffuser core by a filter medium holder, wherein the filter medium is fixed between the purification diffuser core and the filter medium holder and the filter medium holder is attached to the purification diffuser core.

[0107] Embodiment 35. The purifying diffuser of any one of embodiments 25 to 29, wherein the filter medium is a porous hydrophobic membrane comprising polyolefin, polyester, polysulfone, or fluoropolymer.

[0108] Embodiment 36. The purification diffuser of any one of embodiments 25 to 35, wherein the filter medium has a thickness between 10 microns and 1300 microns.

[0109] Embodiment 37. A purification diffuser according to any one of embodiments 25 to 36, wherein the purification diffuser core further comprises one or more deflectors, wherein the one or more deflectors protrude from the inner surface of the purification diffuser core bordering the internal purification gas channel into the internal purification gas channel.

[0110] Embodiment 38. A purification diffuser according to Embodiment 37, wherein one or more diverters bridge across the internal purification gas channel from a first position on the inner surface of the purification diffuser core to a second position on the inner surface of the purification diffuser core, the second position being separate from the first position.

[0111] Embodiment 39. A purge diffuser according to Embodiment 37 or 38, wherein the diffuser core includes one or more diverters in a first section of the internal purge gas channel proximal to the purge port connector and includes no diverters in a second section of the internal purge gas channel distal to the purge port connector.

[0112] Embodiment 40. The purification diffuser of Embodiment 39, wherein the first section is smaller than the second section.

[0113] Embodiment 41. A purification diffuser according to any one of Embodiments 25 to 40, wherein the diffuser ports are staggered so that each portion of the internal purification gas channel between the diffuser port closest to the purification port connector and the diffuser port farthest from the purification port connector can be accessed through the diffuser port along a line perpendicular to the length of the purification diffuser.

[0114] Embodiment 42. A method of manufacturing the purification diffuser according to any one of embodiments 25 to 41, comprising:

[0115] a) molding the purge diffuser core as a single unitary article; and

[0116] b) securing filter media to the outer surface of the purification diffuser core.

[0117] Embodiment 43. The method according to embodiment 42, wherein step a) is performed by injection molding.

[0118] Embodiment 44. The method according to embodiment 42 or 43, wherein step b) is performed by welding.

[0119] Embodiment 45. The method according to embodiment 42 or 43, wherein step b) is performed by pulse welding.

[0120] Embodiment 46. The method according to embodiment 42 or 43, wherein step b) is accomplished by attaching a filter media holder, wherein the filter media is fixed between the purification diffuser core and the filter media holder and the filter media holder is attached to the purification diffuser core.

[0121] Embodiment 47. A method of purging the system for transporting substrates according to any one of embodiments 1 to 24, comprising flowing a purge gas through the purge port into the purge diffuser and thereby into the interior of the substrate container.

[0122] Embodiment 48. The method of embodiment 47, wherein the purge gas is nitrogen.

[0123] Embodiment 49. The method of embodiment 47, wherein the purge gas is clean dry air (CDA).

[0124] Embodiment 50 The method of Embodiment 47, wherein the purge diffuser provides a greater flow of purge gas to a lower portion of the interior of the substrate container than to a higher portion of the interior of the substrate container.

[0125] Various modifications and alterations of the present invention will be apparent to those skilled in the art without departing from the scope and principles of the invention, and it should be understood that the invention should not be strictly limited to the illustrative embodiments set forth above.

Claims

1. A purge diffuser for use in a system for transporting a substrate, comprising: i) a purge diffuser core having an inner purge gas channel, one or more diffuser ports, and an outer surface, wherein the diffuser ports are arranged in a plurality of rows along the longitudinal direction of the purge diffuser core; ii) a filter medium secured to the outer surface of the purifying diffuser core; and iii) a purge port connector for mounting the purge diffuser to a purge port of a substrate container for transporting substrates; The purge diffuser is arranged so that there is a continuous path for purge gas entering through the purge port connector to enter the internal purge gas passage, exit the internal purge gas passage through the diffuser port, and pass through the filter media.

2. The purge diffuser of claim 1, wherein the purge diffuser core is a single piece.

3. The purge diffuser of claim 1, wherein the purge diffuser core is a monolithic article comprising an injection moldable, melt processable polymer.

4. The purifying diffuser of any one of claims 1 to 3, wherein the filter media is directly bonded to the outer surface of the purifying diffuser core by a welding bond.

5. The purification diffuser of any one of claims 1 to 3, wherein the filter medium is fixed to the outer surface of the purification diffuser core by an adhesive.

6. The purification diffuser of any one of claims 1 to 3, further comprising a scrim disposed on the filter media.

7. The purifying diffuser of any one of claims 1 to 3, wherein the filter medium is a porous hydrophobic membrane comprising polyolefin, polyester, polysulfone or fluoropolymer.

8. The purifying diffuser of any one of claims 1 to 3, wherein the filter medium is a hydrophobic membrane comprising polyolefin, polyester, polysulfone or fluoropolymer.

9. The purifying diffuser of any one of claims 1 to 3, wherein the filter medium is a hydrophobic ultra high molecular weight polyethylene membrane.

10. The purge diffuser of any one of claims 1 to 3, wherein the purge diffuser core further comprises one or more diverters protruding into the internal purge gas passage from an inner surface of the purge diffuser core bordering the internal purge gas passage.

11. A purge diffuser according to any one of claims 1 to 3, wherein the diffuser ports in different rows are staggered so that each portion of the internal purge gas channel between the diffuser port closest to the purge port connector and the diffuser port farthest from the purge port connector is accessible through a diffuser port along a line perpendicular to the length of the purge diffuser.

12. A system for transporting a substrate, comprising: a) a substrate container comprising a container portion having an opening, a door adapted to be received in the opening, and a purge port for admitting a purge gas to an interior of the container portion; and b) A purge diffuser as claimed in any one of claims 1 to 11 mounted to the purge port via the purge port connector, the purge diffuser being arranged so that there is a continuous path for purge gas entering through the purge port to enter the internal purge gas passage, exit the internal purge gas passage through the diffuser port, and enter the interior of the substrate container through the filter media.

13. The system of claim 12, wherein the purge port is defined in a first wall of the substrate container, the first wall facing an opposing wall of the substrate container across the interior of the substrate container; wherein the height of the substrate container is measured from a top wall to a bottom wall of the container portion and wherein the length of the purge diffuser does not exceed 85% of the height of the substrate container.

14. The system of any one of claims 12 to 13, wherein the substrate container is a front opening pod (FOUP).

15. A method of manufacturing a purification diffuser according to any one of claims 1 to 11, comprising: a) molding the purge diffuser core as a single unitary article; and b) securing filter media to the outer surface of the purification diffuser core.

16. The method according to claim 15, wherein step a) is performed by injection molding.

17. The method according to claim 15 or 16, wherein step b) is performed by welding.

18. A method of purging a system for transporting substrates according to any one of claims 12 to 14, comprising flowing a purge gas through the purge port into the purge diffuser and thereby into the interior of the substrate container.

19. The method of claim 18, wherein the purge gas is nitrogen and the purge diffuser provides a greater flow of purge gas to a lower portion of the interior of the substrate container than to an upper portion of the interior of the substrate container.

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