Cross-Reference to Related Application

This application claims the benefit of and priority to U.S. Provisional Application No.

62/517,262 filed on June 9, 2017, the contents of which are incorporated herein by reference in their entirety for all purposes.

Technical Field

The disclosure relates generally to substrate containers for retaining wafers, flat panels, other substrates and the like for transport, storage, and processing. More particularly, the disclosure relates to a front opening substrate container including a channel for modulating gas flow to reduce a quantity of particles within a gas stream

Background

Substrate containers and carriers are utilized for holding, transporting, and storing substrates before, during and after processing. Such substrates are used in the fabrication of semiconductors such as integrated circuits and liquid crystal display panels. In their transformation into the end product, these delicate and highly valuable substrates are subjected to repeated processing, storage, and transportation. Such substrates must be protected from damage from particulate contaminants, static discharges, physical damage from breakage, or contamination from vapors or gasses such as those outgassing from materials used in processing.

Such substrate containers have controlled limits for the number of particles allowed on a substrate after transportation and storage. Particles may be generated by a variety of internal and external surfaces and may be deposited onto substrate surfaces during transport and storage.

Traditionally, gaskets have been used to provide a barrier between the internal environment of the container and the environment external to the container in an effort to reduce the number of particles that may be introduced into the container from the environment external container. However, the materials used to provide such a barrier may also be a source of undesirable contaminates such as metals/oils/volatiles which have been shown to contribute to the quantity of particles found within the container's internal environment. As such, additional or alternative solutions for controlling and or reducing the number of particles within a substrate container are needed. Summary

The disclosure relates generally to substrate containers for retaining wafers, flat panels, other substrates and the like for transport, storage, and processing. More particularly, the disclosure relates to a front opening substrate container including a channel for modulating a gas flow of a gas stream within the channel to reduce a quantity of particles within the gas stream.

In one illustrative embodiment, a substrate container includes: a container portion defining an interior; a door frame defined by the container portion; a door receivable in the door frame; and a channel defined between the door frame and the door. The channel is configured to modulate a gas flow of a gas stream containing a quantity of particles within the channel to separate at least some parties from the quantity of particles within the gas stream.

In some embodiments, the channel can include at least one directional change having a change in direction ranging from about 70 degrees to about 110 degrees or from about 80 degrees to about 100 degrees or, more particularly, from about 85 degrees to about 95 degrees. In some cases, the channel includes at least one directional change having a change in direction of about 90 degrees. In other embodiments, the channel includes two or more undulations or curved sections.

In some embodiments, the channel defines a first volume and a second volume, wherein the second volume is greater than the first volume.

In some embodiments, the door and the door frame include complimentary features. In one example, the door includes a projection and the door frame includes a recess configured to receive the projection of the door. In another example, the door frame includes a projection and the door comprises a recess configured to receive the projection of the frame.

In another illustrative embodiment, a method includes reducing a quantity of particles contained within a gas stream by modulating a gas flow of the gas stream within a channel defined between a door and a door frame of a substrate container.

The preceding summary is provided to facilitate an understanding of some of the innovative features unique to the present disclosure and is not intended to be a full description. A full appreciation of the disclosure can be gained by taking the entire specification, claims, drawings, and abstract as a whole. Brief Description of the Drawing

The disclosure may be more completely understood in consideration of the following description of various illustrative embodiments in connection with the accompanying drawings, in which:

Figure 1 is a perspective view of an exemplary substrate in accordance with various embodiments of the disclosure;

Figure 2 is another perspective view of the substrate container shown in Figure 1 with the door removed;

Figure 3 is a top, plan view of the substrate container shown in Figure 1 ;

Figure 4 is a bottom, plan view of the substrate container shown in Figure 1;

Figure 5 is a partial, cross-sectional view of the substrate container shown in Figure 1;

Figures 6-12 are schematic representations of a channel for modulating a gas flow in accordance with various embodiments of the disclosure; and

Figure 13 is a schematic representation of gas stream containing particles flowing within a channel.

While the disclosure is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the disclosure to the particular illustrative embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.

Detailed Description

As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

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 drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the disclosure. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary. While the details of the disclosure are described within the context of a front opening substrate container, it will be generally recognized by those of skill in the art that the same or similar principals and features may be incorporated into a bottom opening substrate container such as a reticle pod, a reticle standard mechanical interface (SMIF) pod, or an extreme ultraviolet (EUV) pod.

Figures 1-4 show different views of an exemplary substrate container 10 for storing or transporting one or more silicon wafers or other substrates. The container 10 can be any one of a front opening substrate container including a front opening shipping box (FOSB), a front opening unified pod (FOUP), or a multi-application carrier (MAC) configured to contain one or more wafers or other substrates. The substrate container 10, according to the various embodiments disclosed herein, generally includes a container portion 20 defining a door frame 22, a door 24 receivable within the door frame 22, and a bottom plate 26. The container portion 20 generally has a top wall 30, a bottom wall 32, side walls 34, and a rear or back wall 36, which together define an open interior. A pair of side handles (not shown) can be provided on the left and right side walls 34 of the container portion 20 so that the container 10 may be picked up and manually moved by a person. Wafer supports 40 for supporting one or more substrates such as, for example, a wafer, as can be in seen in Figure 2, and can be positioned in the interior, adjacent the inner surfaces of each of the sides walls 34 of the container portion 20. Additionally, the substrate container 10 can include a flange 44 which facilitates transport within a fabrication facility via an overheard transport (OHT) system, and an integrated or separate kinematic coupling component 47. In some cases, as best viewed in Figure 3, the kinematic coupling component can have a V-groove 48 for interfacing with the kinematic coupling (KC) pins provided on the automation equipment within a fabrication facility.

The substrate container 10 may be made from a variety of materials and more particularly, a thermoplastic polymer that is designed to minimize particle shedding. In some cases, a portion, if not all, of the substrate container 10 may include an electrostatic dissipative material. In other cases, a portion, if not all, of the substrate container 20 can be fabricated from a moisture barrier material having a low water vapor transmission rate. A portion, if not all of the substrate container 10, can be injection molded.

According to various embodiments, as best viewed in Figure 5, the substrate container 10 includes a channel 50 for modulating a gas flow velocity of a gas stream within the channel to mitigate and more particularly, reduce a quantity of particles within the gas stream before the gas stream passes from the channel 50 and into the interior of the container portion 20. The number of particles within the gas stream are reduced by separating a least some particles from a larger quantity of particles contained within the gas stream as the gas flows through the channel 50. The channel 50 is defined between a wall of the container door 24 and a wall of the door frame 22 defined by the container portion 20. In some embodiments, the channel 50 is continuous about an outer perimeter of the door 24. The container 10 does not include a gasket disposed within the channel 50, as is conventional.

A gas stream is caused to flow within the channel 50 due to a pressure differential that exists between the environment external to the substrate container (external environment) and the environment within the substrate container (internal environment). Changes in this pressure differential can occur during transport or storage of the container and can be attributed to changes in temperature, changes in altitude, changes in barometric pressure, and the like. Typically, the pressure of the internal environment is less than the pressure of the external environment, and it is this pressure gradient that drives the gas stream into the channel 50 and subsequently, into the internal environment of the container 10.

The channel 50 is configured such that it operates on the principle of inertial impaction.

More particularly, the channel 50 is configured such that it modulates a gas flow velocity of a gas stream flowing within the channel 50 to mitigate and more particularly, separate at least some particles from a larger quantity of particles contained within the gas stream. As will be described in greater detail herein, the channel 50 includes a plurality of sections through which the gas stream passes, directing any airborne particles toward a wall of the channel 50 in that section which acts as a collection surface. Whether a particular particle impacts on the collection surface defined by the channel wall while flowing through a selected portion of the channel depends on the size of the particle. Size can be determined by size, mass, or a combination of mass and size. Particles of larger sizes have greater inertia and will impact on the wall of a select section of the channel 50, while particles of smaller sizes have less inertia and will remain entrained in the gas stream and pass to the next section of the channel 50 where the process is repeated. A change in gas flow velocity causes certain particles to impact on a wall of a particular section of the channel thereby removing those particles from the gas stream. Changes in gas flow velocity can be effected by changes in a volume between two adjacent sections of the channel 50, by a change in direction between two adjacent sections of the channel 50, or by a combination of a change in direction and change in volume between two adjacent sections of the channel 50.

Figures 6-12 provide several schematic representations of a channel 50A-50G (collectively 50) that can be defined between a wall 52 of the door 24 and a wall 54 of the door frame 22 of a substrate container such as, for example, substrate container 10. In many embodiments, the channel 50 can include a plurality of adjacent sections through which a gas stream may flow. Additionally, the channel 50 can include at least one directional change that occurs between two adjacent sections as shown in Figures 6-12. In many embodiments, the channel 50 can include a plurality of directional changes, each directional change occurring between adjacent sections of the channel 50. In use, it is theorized that larger particles will impact on the surfaces of the walls 52, 54 defining the channel 50 where the directional changes occur thereby reducing the number of particles within the gas stream before the gas stream passes into the interior of the container portion.

Turning now to Figures 6 and 7, channel 5 OA includes: a first directional change between adjacent sections 60 and 66; a second directional change between adjacent sections 66 and 72; a third directional change between adjacent sections 72 and 78; and a fourth directional change between adjacent sections 78 and 84. Channel 50A may include additional sections and additional directional changes. Similarly, channel 50B includes: a first directional change between adjacent sections 160 and 166; a second directional change between adjacent sections 166 and 172; a third directional change between adjacent sections 172 and 178; and a fourth directional change between adjacent sections 178 and 184. Channel 50B also may include additional sections and additional directional changes. The directional change occurring between adjacent sections may cause a change in gas flow velocity which in turn may cause larger particles having a greater inertia to impact on a wall of the channel. Smaller particles having less inertia may pass through the directional change. Multiple sections and multiple directional changes may be provided such that the process is repeated, thereby causing a reduction in the number of particles container within the gas stream as they become trapped at various locations within the channel. Figures 8-12 also show embodiments in which channels 50C-50G include multiple sections and multiple directional changes.

The degree of the directional change can be measured by an angle a that is defined between a first section and a second section such as, for example, sections 60 and 66 of channel 50A shown in Figure 6 or first and second sections 160, 166 of channel 50B shown in Figure 7. The directional change, as measured by the angle a, can have a change in direction ranging from about 70 degrees to about 110 degrees; from about 80 degrees to about 100 degrees; from about 85 degrees to about 95 degrees; and more particularly of about 90 degrees. Figure 6 shows an embodiment in which the direction change between two adjacent sections 60, 66 is about 90 degrees. Figure 7 shows an embodiment in which the directional change between two adjacent sections 160, 166 is about 100 degrees. Figures 8-11 show embodiments in which the channel 50C, 50D, 50E, 50F, includes a change in volume between two adjacent sections in addition to a directional change. The arrow indicates the direction of flow of the gas stream within the channel. As shown in Figure 8, channel 50C includes a directional change and a volume change between adjacent sections 266 and 272. Similarly, channel 50D of Figure 9 includes a directional change and a volume change between adjacent sections 366 and 372. Channel 50E includes a directional change and a volume change between sections 466 and 472, and channel 50F includes a directional change and a volume change between sections 566 and 572. In each embodiment, as shown, the upstream section (e.g. sections 266, 366, 466, 566) of each of the channels 50A-50F has smaller volume than the adjacent downstream sections (sections 272, 372, 472, 572) of the channels 50A-50F. Arranging the sections of the channel such that a downstream section of the channel has a greater volume than a volume of an adjacent upstream section of the channel provides a diffusion volume to cause the diffusion filtration of certain particles contained within the gas stream, thereby removing additional particle from the gas stream.

Figure 12 schematically represents yet another embodiment of the disclosure. In some embodiments, as shown in Figure 12, the channel 50G can include a plurality of curved sections or undulations 600, 606, 612, 618, 624, 630, 636 through which a gas stream may flow. The curved sections provide a plurality of directional changes between adjacent sections of the channel. In use, as described herein, it is theorized that larger particles will impact on the surfaces of the walls 52, 54 defining the channel 50G where the directional changes occur thereby reducing the number of particles within the gas stream. As shown in Figure 12, the channel 50G includes six curved portions. However, it will be generally recognized that the number of curved sections can vary.

In some embodiments, as shown in Figures 6, 7 and 12, each of the walls 52, 54 of the door 24 and container portion 22 can be configured such that they define complimentary features.

Complimentary features are structural features having a general size and shape that correspond to one another such that a first structure is capable of receiving a second structure. For example, as shown in Figure 6, the wall 52 of the door 24 can define a projection 190 and the wall 54 of the door frame 22 can define a recess 192. In other embodiments, the wall 54 of the door frame may define at least one projection and the wall 52 of the door 24 can define a corresponding recess. As shown in Figures 6, 7 and 12, the recess 192 may have a size and shape that is corresponding to the size and shape of the projection 190, but this is not required in all embodiments as shown in Figures 8 and 9. Figures 8-10 depict embodiments in which a recess 194 is defined by wall 54 of the door frame defines an opening having a width w and a depth d that is sized to receive a projection 196 defined by the wall 52 of the door 24. However, the overall shape of the recess does not correspond to the shape of the projection.

Referring now to Figure 13, a gas stream containing a quantity of particles flows within the channel 750 in the direction of the arrows due to a pressure differential that exists between the environment external to the substrate (external environment) and the environment within the substrate container (internal environment). Upon reaching the first directional change A, particles having sufficient inertia impact a channel wall and are retained on a collection surface defined by either wall. Smaller particles having less inertia contained within the gas stream flow to the next section 752. Additional particles may be removed from the gas stream through inertial impaction at the next directional change B. The increase in volume provided by section 754 dilutes the gas stream and filters additional particles from the gas stream via diffusion. The dilution of volume decreases the statistical probability that the particles will enter the next section of the channel.

Additionally, section 754 can increase the residence time of the gas stream within the channel 750 which, in turn, increases the diffusion efficiency of the channel.

Having thus described several illustrative embodiments of the present disclosure, those of skill in the art will readily appreciate that yet other embodiments may be made and used within the scope of the claims hereto attached. Numerous advantages of the disclosure covered by this document have been set forth in the foregoing description. It will be understood, however, that this disclosure is, in many respect, only illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of parts without exceeding the scope of the disclosure. The disclosure's scope is, of course, defined in the language in which the appended claims are expressed.