Storage pod, outer pod, storage stocker, dual pod

Abstract

The invention provides a storage pod (110) for storage of a single reticle (200), especially an EUV reticle, the storage pod (110) comprising a base plate (112) and a cover (114) defining an interior space (111) the interior space (111) being configured and adapted to hold said single reticle, the storage pod (110) further comprising at least one gas inlet interface (120) for providing a purge gas (210) to the interior space (111), wherein a gas flow of the purge gas (210) into the interior space (111) is independent from an atmosphere surrounding the storage pod (110). Further, an outer pod (300) for containing such a storage pod (110) and a storage stocker for storing storage pods (110) with or without such outer pods (300) are disclosed.

Description

[0001] Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0002] IDF3249 & 3250 06 May 2025

[0003] 1

[0004] Storage Pod, Outer Pod, Storage Stocker, Dual Pod

[0005] The present invention relates to a storage pod and an outer pod for storage of reticles, especially EUV reticles, and a corresponding storage stocker, as well as a dual pod.

[0006] Background

[0007] Photolithography processes are widely used as one of the key steps in the manufacture of integrated circuits (ICs) and other semiconductor-related devices and / or structures.

[0008] However, as the dimensions of features produced by such processes decrease, the importance of photolithography for the production of miniature ICs or other devices and / or structures rises.

[0009] In photolithography, a geometric pattern is transferred from a photomask (typically referred to as reticle) onto a substrate, for example a semiconductor wafer, by the use of light, a photosensitive layer and a subseguent etching step. Depending on the desired feature size on the substrate, the feature size of the reticle needs to be adapted as well as the wavelength of the light used for pattern transfer, with consideration of the Rayleigh criterion.

[0010] In order to reduce the smallest achievable feature size, it has been proposed to use extreme ultraviolet (EUV) radiation. EUV radiation is electromagnetic radiation having a wavelength within the range of 5-20 nm, for example within the range of 5-10 nm.

[0011] Any contamination of the reticle may reduce the imaging performance of the photolithographic process and may in more serious cases reguire the reticle to be replaced. The reticle is typically expensive and therefore any reduction in the freguency with which it must be replaced is advantageous. Furthermore, replacement of the reticle is a timeconsuming process, during which the photolithographic process may have to be suspended, thereby reducing its efficiency, which is undesirable.

[0012] For EUV applications, particle contamination with particle sizes of less than 10 nm as well as chemical contamination, for example by adsorption of volatile organic compounds, can be relevant. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0013] IDF3249 & 3250 06 May 2025

[0014] 2

[0015] The reticles used for such EUV applications are therefore typically stored in a storage stocker, referred to in the following simply as a stocker, or more generally, as place of storage, and retrieved when needed in connection with the lithography exposure equipment. When they are to be used, reticles are transported, usually within a semiconductor fabrication plant, commonly referred to as a fab or FAB, from such a stocker to process tools. Usually, the reticles are stored in a double shell container (dual pod) comprising a so- called EUV outer pod (EOP) and an EUV inner pod (EIP) during transportation as well as for storage within the stocker.

[0016] Such a dual pod is described in further detail in US 2019 / 0214287 A1, for example.

[0017] Since the acceptable level of particle contamination is extremely low, friction (which leads to abrasion and thus particle generation) of the reticle against the container as well as friction of container components relative to one another needs to be avoided. Therefore, typical EIPs are designed so as to accommodate one reticle in such a way that it has only very limited possibilities to move therein. They are also equipped with an additional reticle retainer configured and adapted to immobilize the reticle inside the EIP. In order to prevent contamination, the EIP is designed to enable a protective gas or vacuum to be applied to the reticle. To that end, typically orifices equipped with filter material are provided for the protective gas to enter from the EOP into the surroundings of the reticle contained in the respective EIP.

[0018] The EOP is equipped with an actuator adapted to bias the reticle immobilization means of the EIP into a retaining position, thereby immobilizing the reticle inside the EIP when the EOP is attached to the EIP. The EOP also functions to immobilize the typically two components of the EIP, usually referred to as base plate and cover, against one another to prevent friction induced abrasion.

[0019] It is to be understood that the EIP components are moveable against one another as long as they are not immobilized from outside. In order to avoid friction induced abrasion caused by such movement, the EOP conventionally provides such immobilization functionality for the EIP while also providing protection against the surrounding atmosphere, which is necessary e.g. during transport between a storing position and process tools requiring reticles for operation. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0020] IDF3249 & 3250 06 May 2025

[0021] 3

[0022] EOPs are rather bulky, leading to high space requirements or "footprint" for stockers storing EUV reticles. Furthermore, they are made of polymeric material, which is also prone to abrasion and outgassing of volatile organic compounds.

[0023] From WO2023078589A1 there is known a stocker system, in which a plurality of storage pods is used for the storage of reticles. These stocker pods comprise a single pod, a plurality of stocker pods being stackable one upon the other. Compared to storage systems using EIPs and EOPs, this stocker system has significantly lower space requirements.

[0024] In typical systems, an inner volume of the EIP, i.e. an area, in which reticles are stored, may be purged with a purge gas which is provided to the EIP by purging an atmosphere surrounding the EIP and letting the purge gas diffuse into the inner volume of the EIP via a purging orifice.

[0025] Summary of the Invention

[0026] The present invention seeks to improve such a stocker system utilising single pods for storage, and provides a stocker pod, an outer pod and a storage stocker according to the respective independent claims.

[0027] The invention provides a storage pod similar to a traditional inner pod (EIP) with the additional functionality of providing a flow of purge gas therethrough. Thereby the storage conditions of reticles may be drastically improved. Particularly, the invention enables greatly reduced purging times while at the same time drastically reducing the amount of purge gas needed to reach certain purity levels (e.g. reducing a humidity level within the storage pod to values below a predefined threshold). The outer pod and storage stocker according to the invention provide respective purge gas connections in order to fully utilize the improved features of said storage pod.

[0028] Specifically, in a first aspect, the invention provides a storage pod for storage of a single reticle, especially an EUV reticle, the storage pod comprising a base plate and a cover defining an interior space, the interior space being configured and adapted to hold said single reticle, the storage pod further comprising at least one gas inlet interface for providing a purge gas to the interior space, wherein a gas flow of the purge gas into the interior space is independent from an atmosphere surrounding the storage pod), and wherein the gas inlet interface is configured to guide at least 90% of the purge gas supplied to the gas inlet Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0029] IDF3249 & 3250 06 May 2025

[0030] 4 interface into the interior space of the storage pod. Particularly, substantially the entire purge gas entering the storage pod via the gas inlet interface is guided into the interior space, i.e. only unavoidable leakage streams and / or similar losses are not guided into the interior space. This enables a much more purpose-oriented use of the purge gas as compared to conventional arrangement relying on diffusion, thereby also significantly reducing the required amount of purge gas and / or significantly improving the storage conditions of the stored reticle, which also translates into a higher overall yield of the semiconductor fabrication facility, i.e. the photolithography process utilizing the stored reticles.

[0031] Stacked storage pods, such as disclosed in EP24158699.9, have the advantage of a higher storage density compared to single storage pods. Accessing a storage pod within a stack requires only minimal space in height for separating the stack and accessing or retrieving a specific storage pod.

[0032] A stack, however, has the following disadvantages:

[0033] - The handling system must be capable of lifting the complete stack in order to access or retrieve storage pods at the bottom of the stack. This requires a lifter unit with a high payload.

[0034] - Accessing a storage pod within a stack causes motion with possible particle generation to all storage pods stacked on top of the storage pod accessed.

[0035] The embodiments of this invention adopt the idea of direct vertical purging from EP24158699.9 and apply it to a single storage pod. This enables an improvement of (EUV) reticle storage conditions and / or performance and a simplified tool concept in comparison to prior art solutions. Particularly, handlers traditionally used in single reticle stockers can be used in connection with embodiments according to this invention while at the same time providing improved storage conditions related to the direct purge of the interior space within the storage pod.

[0036] Advantageous embodiments and additional features are provided in the dependent claims and further discussed in the following description.

[0037] According to at least one embodiment, the gas inlet interface comprises a pressure port, preferably located in the base plate, for providing the purge gas to the storage pod from outside the storage pod, an inlet orifice, preferably located in the cover, for allowing the purge gas to enter the interior space, and a connection line between the pressure port and Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0038] IDF3249 & 3250 06 May 2025

[0039] 5 the inlet orifice for guiding the purge gas from pressure port to the inlet orifice. Utilizing a pressurized purge gas enables a pressure difference between the interior space and the atmosphere surrounding the storage pod, thereby effectively avoiding any contaminant ingress into the interior space, which again improves the storage conditions and thereby the yield of the photolithography process.

[0040] According to at least one embodiment, the storage pod further comprises at least one gas outlet interface for withdrawing the purge gas from the interior space independently from the atmosphere surrounding the storage pod. Particularly, the at least one gas outlet interface may comprise a suction port, preferably located in the base plate, configured to allow application of a suction pressure below a pressure of the purge gas at the gas inlet interface, an outlet orifice, preferably located in the base plate, configured to accept purge gas from the interior space and an outlet connection line between the outlet orifice and the suction port for guiding the purge gas accepted by the outlet orifice to the suction port. This enables, for example, recycling the spent purge gas and / or using purge gases which might be harmful to operators of the storage equipment. Since, according to these embodiments, the purge gas is guided in a substantially closed system independent from the surrounding atmosphere, the purge gas can be chosen independently, i.e. without considering constraints regarding this surrounding atmosphere. This is in contrast to conventional systems, where operator safety may depend on the chosen purge gas. For example, traditionally clean dry air (CDA) or the like is used as a purge gas in order to make sure that operators can breathe. Embodiments of the invention, by contrast, can use oxygen-free (or at least oxygen-depleted) purge gases such as argon or nitrogen, for example. This provides an advantage as purge gases with a low oxygen content provide an additional chemical protection to the stored reticles.

[0041] Expediently, each storage pod is provided with a mechanism for securing base plate and cover to one another in a releasable manner. For example, each storage pod is provided with a latch mechanism for securing base plate and cover to one another. Such a latch mechanism can comprise a number of latches, and ensure a gas tight connection between base plate and cover, these components usually being made of a metal material. Especially, such a latch mechanism is adapted to prevent relative movement of base plate and cover relative to one another in a locked state, thereby preventing abrasion. Also, the latch mechanism can be adapted to immobilise a reticle within a storage pod relative to the storage pod, which also minimises abrasion and contamination effects. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0042] IDF3249 & 3250 06 May 2025

[0043] 6

[0044] As an effective purge of the interior space of the storage pod can be provided according to the invention, the storage pod can be partially or completely made of suitable plastics materials, as outgassing effects can effectively be counteracted by the purge gas flowing in the storage pod. The storage pod can also be partially or completely made of metal materials.

[0045] According to a second aspect of the invention, an outer pod is provided, wherein the outer pod is configured to contain one storage pod as described herein before within an inner volume of the outer pod, the outer pod comprising at least one gas inlet terminal configured to provide purge gas to the at least one gas inlet interface of the storage pod within the inner volume of the outer pod, without providing the purge gas to the inner volume of the outer pod. This enables using the storage pod of this invention as a replacement for conventional EIPs, i.e. as transport containers for transporting reticles inside a semiconductor fabrication facility (also referred to as fab), for example, thereby improving the cleanliness of the stored and / or transported reticle even further.

[0046] According to at least one embodiment, the outer pod may further comprise at least one gas outlet terminal configured to accept purge gas from the at least one outlet interface of a storage pod contained within the inner volume, when the storage pod comprises at least one gas outlet interface for withdrawing the purge gas from the interior space of the storage pod. Preferably, the outlet terminal is configured to guide the purge gas accepted or withdrawn from the storage pod to an outer surface of the outer pod such that the purge gas is substantially prevented from entering the inner volume of the outer pod surrounding the storage pod. This, as described herein above in connection with the respective embodiment of the storage pod, enables recycling of the purge gas and / or utilizing gases otherwise not usable as the purge gas with the respective advantages mentioned above.

[0047] A third aspect of the invention provides a storage stocker configured to store a number of storage pods as described hereinbefore, wherein the storage pods are stored in respective storage positions within the stocker, each of the storage pods being contained within an outer pod according to an embodiment of this invention or stored in the storage position without any outer pod, the storage positions each being configured with a purge gas supply to provide a purge gas to the at least one gas inlet interface of the storage pod and / or the gas inlet terminal of the outer pod, respectively. This enables realizing the above explained advantages. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0048] IDF3249 & 3250 06 May 2025

[0049] 7

[0050] According to at least one embodiment, the storage stocker comprises a securing mechanism adapted to physically (e.g. mechanically) secure each storage pod within its respective storage position. This prevents physical damages to the stored reticles, for example by friction induced abrasion due to vibrations, for example in the event of an earthquake or an accident in the vicinity of the stocker.

[0051] According to a preferred embodiment of the storage stocker, a securing mechanism adapted to physically secure individual storage pods within their respective storage positions is provided.

[0052] Aspects which may be taken into account when developing such an improved storage concept include that it is highly undesirable to change the way the reticles are provided to the photolithographic process equipment, this typically being the most complicated and costly part of a semiconductor production facility. Therefore, the invention, in an additional aspect, provides a dual pod including a storage pod according to any one of the embodiments of the storage pod according to the invention described herein and an outer pod according to any one of the embodiments of the outer pod according to the invention described herein.

[0053] Brief description of the drawings

[0054] Advantages and further aspects of the invention will now be discussed further with reference to the appended drawings. Herein,

[0055] Figures 1 A to 1 F show schematic views of preferred embodiments of a storage pod according to the invention.

[0056] Figures 2 and 3 schematically illustrate a purge gas flow around a reticle stored within the storage pod of Figures 1 A to 1 F.

[0057] Figure 4 shows a schematic side view of a storage pod according to an embodiment of the invention being contained within an outer pod according an embodiment of the invention.

[0058] In Figures 1 A to 1 F, embodiments of a storage pod configured and adapted for storing a reticle within a reticle stocker are schematically shown and designated 110. The storage pod 110 comprises a base plate 112 and a cover 114. Figures 1A to 1E show the storage pod Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0059] IDF3249 & 3250 06 May 2025

[0060] 8

[0061] 110 in a closed state, in which it usually houses a (single) reticle (schematically shown in Figure 4 and designated 200). In Figure 1F, the storage pod 110 is depicted in an open state, in which the base plate 112 and the cover 114 are spaced apart or detached from one another. The storage pod defines an interior space 111, in which reticle 200 is housed, as can especially be seen in Figure 4. Each single storage pod 110 may be stored individually, for example, on a shelf location in a storage stocker.

[0062] Kinematic coupling pins may be provided on the shelf and corresponding kinematic coupling grooves 113 (see Fig. 1B, 1C) on the bottom side of the baseplate 112 of the storage pod 110 to ensure a stable and repeatable position of the storage pod 110 in the shelf.

[0063] Base plate 112 and cover 114 are held together by a latch mechanism (schematically shown in Figures 1 D and 1E and designated 116). Typically, the latch mechanism 116 can be provided to define two or three states, a locked state, in which base plate 112 and cover 114 are tightly closed, providing a protected interior (interior space 111) therebetween, an unlocked state, in which base plate 112 and cover 114 can be separated from one another, for example in order to load or unload reticles, and, optionally, an idle state, in which the latch mechanism 116 is disabled for usage in or with other tools, for example for cleaning.

[0064] The storage pod 110 is provided with a fixing mechanism (not shown) for fixing a reticle inside the storage pod 110, when the storage pod is in its closed position, which further minimises potential contamination due to abrasion effects caused by movement of the reticle 200 in the storage pod. Advantageously, the latch mechanism 116 and the fixing mechanism are adapted to cooperate to fix the base plate 112 and the cover 114 relative to one another, as mentioned above, and the reticle 200 relative to the storage pod 110.

[0065] On each side or at least on two opposite sides of storage pod 110, there is provided a handling member 115, such as a handling flange or a handle. Providing handling members 115 on each side enables a handling robot to grip the storage pod 110 from any side, without the necessity of rotating the storage pod. In the embodiment shown, the handling members 115 are provided on the cover 114. It is also conceivable to provide them on the base plate 112, or for example two on opposite sides of the base plate, and two on different or the same opposite sides of the cover, whereby individual handling of the base plate or the cover by the handling robot is rendered possible or at least simplified. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0066] IDF3249 & 3250 06 May 2025

[0067] 9

[0068] The dimensions of the storage pods 110, i.e. their size and shape, are preferably fully compatible with existing fully automated EUV pod cleaning equipment. Particularly, the storage pod 110 may have the same or substantially the same dimensions as a typical EIP conventionally used for storing and / or transporting EUV reticles.

[0069] The storage pod 110, in the example shown, is provided with a gas inlet interface 120 comprising a pressure port 122, a gas inlet connection line 124 and an inlet orifice 126. The pressure port 122 is located in the base plate 112 and the inlet orifice 126 in cover 114. The pressure port 122 may be provided in a recess in the base plate 112 configured as the above mentioned kinematic coupling groove 113 (as in Figures 1B and 1D) or, alternatively, may be provided in the baseplate 112 outside (or in absence) of such a kinematic coupling groove 113 (as in Figures 1C and 1E).

[0070] The purge gas supplied to the gas inlet interface 120 via the pressure port 122 from the base plate 112 is guided to the inlet orifice 126 in the center position of the storage pod cover 114 via the gas inlet connection line 124, as depicted in Fig. 1F. The purge gas is then exhausted via a gas outlet interface 130 comprising an outlet orifice 136 in the center of the base plate 112, an outlet connection line 134 and a suction port 132, all of which, in the example shown, are provided within the base plate 112. Similar to the pressure port 122, the suction port 132 may be provided in a recess in the base plate 112 configured as the kinematic coupling groove 113 (as in Figures 1 B and 1 D) or, alternatively, may be provided in the baseplate 112 outside (or in absence) of such a kinematic coupling groove 113 (as in Figures 1C and 1E). As illustrated in Figures 1B and 1C, the pressure port 122 as well as the suction port 132 may be of a same shape as the kinematic coupling grooves 113 or may be provided in a different shape, particularly in a circular shape, thereby facilitating sealing.

[0071] In other words, the kinematic coupling pins may be used as the inlet and outlet connections in addition to the centering function. This simplifies the design and may reduce the friction when a storage pod 110 is picked up from or placed into a respective storage position. The kinematic coupling pins, in such a case, are provided with a hole in the center. The purge gas supply and the exhaust can then be routed through the pins, as can be derived from Figures 1 D and 4.

[0072] Alternatively, dedicated purge nozzles and connections may be used, independently from any kinematic coupling features. The dedicated nozzles, in such a case, may be optimized for their purpose. A better sealing can be implemented, e.g. with O-rings. Furthermore, in Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0073] IDF3249 & 3250 06 May 2025

[0074] 10 such an embodiment, dimensions of kinematic coupling features (groove 113, pin) and purge gas inlet and outlet connections can be defined independently and based on their respective purpose.

[0075] Purging the storage pod 110 with a clean, and optionally humid, purge gas, e.g. nitrogen or super high purity oil free air (SHPOFA) or clean dry air (CDA) provides a clean storage environment regarding particles, chemical contamination and humidity. The direct (pressurized) purge gas supply ensures an efficient purging compared to current diffusionbased purging (EUV Dual Pod). Optionally provided embedded filters (for example within the pressure port 122 and / or the inlet orifice 126 and / or the outlet orifice 136 and / or the suction port 132) protect against particle cross contamination between storage pods 110.

[0076] This results in the gas flow characteristic illustrated in Figures 2 and 3:

[0077] Since there is no direct connection (shortcut) between inlet orifice 126 and outlet orifice 136 when a reticle 200 is present, the purge gas 210 is guided, after impinging on the reticle 200 in an essentially vertical direction, along the top side of the reticle 200 (i.e. in parallel to the reticle), down sideways and to the outlet orifice 136 on the bottom surface of the reticle 200. The purge gas 210 is efficiently replacing the ambient air within the pod 110 in all areas and directions. The dedicated exhaust line with suction port 132 supports the fast gas-exchange within the pod 110. The humidity level drops very fast. This concept with a purge gas supply from the top side and the exhaust on the bottom side ensures that the stored reticle 200 is completely and uniformly surrounded by the purge gas 210.

[0078] The dedicated purge gas outlet interface 130 has the advantage that most of the purge gas 210 can be collected after usage (except some leakage). There is no mixture of the purge gas 210 with the ambient air. Re-usage of the non-diluted purge gas 210 after a recycle process (for example including cleaning and / or cooling the used purge gas) is an option. Direct exhaust of the purge gas 210 to prevent the accumulation of purge gas 210 inside or outside of the reticle stocker is another option. This is an additional safety aspect. The risk of a low oxygen level harming people is minimized that way.

[0079] This concept comprising a purge gas supply via the inlet orifice 126 from the top side of the storage pod 110 and the exhaust via the outlet orifice 136 on the bottom side ensures that the stored reticle 200 is completely and uniformly surrounded by the purge gas 210. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0080] IDF3249 & 3250 06 May 2025

[0081] 11

[0082] In general, direct pod purging is known, for example, for Front-Opening Unified Pods (FOUPs) with purge option. In these prior art solutions, several articles (specifically semiconductor wafers) are stored in a shared container or pod. This means that in prior art solutions, cross contamination between articles stored within the same container or pod cannot be avoided and the distribution of purge gas within the pod depends on the number and location of articles stored therein. By contrast, in the storage pod 110 according to embodiments of the present invention, each storage pod 110 is configured to hold exactly one reticle in a well-defined interior space 111, thereby enabling precise control over the flow characteristics of the purge gas 210 supplied to this interior space 111, as described herein. Cross contamination between stored reticles is effectively eliminated and each stored reticle 200 can be surrounded by an optimal storage atmosphere.

[0083] The vertical purge gas flow, as disclosed herein, from the upper side of the reticle 200 to the bottom side of the reticle 200 has also been introduced in a similar configuration for stacked storage pods in EP24158699.9. The usage of a single storage pod 110 with a similar purge gas distribution concept is the purpose of embodiments of the present invention. This single pod concept reduces the effort for the tool design. Particularly, there is no need to reinforce the handling system or tool design as required for a storage stack. Existing robots and storage units can be used, thereby also reducing investment and development costs.

[0084] Standard dual pods for EUV reticles are defined in SEMI E152. This standard for EUV dual pods defines purge area locations for the so-called outer pod door (designated 312 in Fig. 4). This is a similar concept as already used for conventional reticle pods (e.g. 150mm Reticle SMIF pods, so-called RSP150s).

[0085] The SEMI Standard E152 does not define:

[0086] - A direct purge connection for the EUV inner pod

[0087] - A general purging concept

[0088] Existing EUV dual pod suppliers are using a filter on the top side of the EUV inner pod (EIP) for gas exchange to the reticle storage area, i.e. the interior volume of the EIP. This means that the gas exchange from the outer pod to the inner pod is based on diffusion. A long time is typically needed for a complete gas exchange in the reticle area of the EIP (ambient air replaced by the purge gas, e.g. Nitrogen). It typically requires more than 30 minutes to achieve a humidity level of 10% around the reticle in the EIP. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0089] IDF3249 & 3250 06 May 2025

[0090] 12

[0091] By contrast to this conventional purging procedure, according to embodiments of the present invention as can be seen in Figure 4, purge gas 210 entering outer pod 300 is not directly released into the inner volume of the outer pod 300, but is guided to the gas inlet interface 120 of the storage pod 110 via an inlet terminal 320.

[0092] Thereby, externally provided purge gas 210 is guided directly into the storage pod 110. An optional particle filter may be provided in the inlet terminal 320 of the outer pod 300 and / or the gas inlet interface 120 of the storage pod 110 to remove particles from the purge gas 210. As persons skilled in the art will be aware of, preferred purge gases are, for example, nitrogen, clean dry air (CDA) or Super High Purity Oil Free Air (SHPOFA). This direct purging of the interior space 111 within storage pod 110 provides a faster gas exchange and thereby helps to avoid contamination of the reticle 200 and ensures safe storage conditions in an EUV dual pod stocker, for example.

[0093] The gas from the storage pod 110 can be exhausted (removed from the storage pod) in different ways, depending in particular on the specific configuration of the gas outlet interface 130:

[0094] - The purge gas 210 may be exhausted via the outlet interface 130 of the storage pod 110 into the interior volume of the outer pod 300. The purge gas 210 can then leave the outer pod 300 via the existing purge port areas (e.g. via outlet terminal 330) or via a gap 316 between outer pod door 312 and outer pod shell 314.

[0095] - The purge gas 210 from the storage pod 110 may be accepted completely by the outlet terminal 330 of the outer pod 300 from the outlet interface 130 of the storage pod and then guided to an outer surface of the outer pod 300 by the outlet terminal 330.

[0096] - The purge gas 210 from the storage pod 110 may be partially accepted directly from the outlet interface 130 and guided by the outlet terminal 330 to the outside of outer pod 300 while another part of the purge gas 210 is exhausted from the outlet interface into the interior volume of outer pod 300 (and then exhausted from the outer pod via the outlet terminal 330 or the gap 316 as described above). This ensures on the one hand that the purge gas from the storage pod 110 can easily escape through a direct connection and on the other hand that the outer pod interior volume surrounding the storage pod 110 is also purged. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0097] IDF3249 & 3250 06 May 2025

[0098] 13

[0099] The purging of the storage pod 110 can be implemented according to the concept for vertical purging (i.e. the concept just described, in which the reticle is purged from one vertical side and the purge gas is withdrawn from the opposite vertical side). Alternatively or additionally, the purge gas may be exhausted partially or completely circumventing the outlet interface 130, for example through a gap between the storage pod cover 114 and the base plate 112, into the interior volume of the outer pod 300. This latter option is not shown in the drawings for conciseness.

[0100] Preferably, a storage stocker for EUV dual pods is provided with a dedicated purge gas supply 420 for each storage position as well as dedicated suction lines 430 to remove used purge gas 210.

[0101] The flow of purge gas 210 as described above provides a highly efficient utilisation of purge gas. For example, the purge gas 210 exiting the storage pod 110 (or the outer pod 300) can be collected and recycled, thus reducing the amount of fresh purge gas required for further purging. In prior art solutions, purge gas was not collected in this way after use, but just released into the surrounding atmosphere. Also, the impingement of the purge gas 210 onto the reticle 200 in a vertical direction and the subsequent flow of purge gas 210 around the reticle 200 enables an effective cleaning / purging interaction. Furthermore, since the purge gas 210 is not released in the surrounding of the storage pod 110 but collected, purge gases that are problematic with regard to health and / or safety of human operators, for example purge gases with no or low oxygen content, such as nitrogen or argon, for example, can be used without having to consider such hazards. This also enables using purge gases that are chemically less aggressive (e.g. in terms of corrosivity) towards the stored reticle and / or the storage pod 110, when compared to traditionally used purge gases such as clean dry air (ODA), although these traditionally used purge gases may nevertheless be used in connection with embodiments of the storage pod 110.

[0102] The purge connections (inlet terminal 320, outlet terminal 330) of the outer pod 300 may particularly use the purge port areas as defined in SEMI E152. The improved purge efficiency, however, allows a different usage and / or the usage of less connections. Traditionally, two ports are used as inlet terminal 320 and two ports are used as outlet terminal 330. However, according to embodiments of the invention, different configurations may be used:

[0103] One inlet and one outlet port could be sufficient. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0104] IDF3249 & 3250 06 May 2025

[0105] 14

[0106] Using one inlet port as inlet and three outlet ports would be another option.

[0107] One inlet port and exhaust through existing gaps would work as well; this also ensures purging of the outer pod 300.

[0108] The purge connection of the storage pod 110 is preferred on a location not reserved for other purposes in SEMI E152 in order to prevent interference with other features or incompatibilities.

[0109] A stocker for single storage pods 110 can be implemented much easier with existing components while maintaining the excellent purge capabilities, as compared to a stacked storage solution such as in EP24158699.9. The slightly lower storage density can be compensated by the following advantages:

[0110] Lightweight handling system without stack lifter

[0111] Less bulky storage shelves

[0112] No motion of not affected / accessed storage pods

[0113] Simpler uniform purge gas distribution for all storage pods within a stocker Less loss of purge gas

[0114] A direct purging of the storage pod 110 instead of a diffusion-based purging as known in the prior art improves the gas exchange dramatically. For example, 90% of the gas inside of the storage pod 110 can be replaced in less than one minute even with a low purge rate of between 6 L / min and 1 L / min or even less than 1 L / min, wherein the volumetric flow rate refers to standard conditions (0 °C, 101.3 kPa). The relative humidity drops below 10% much faster than in prior art solutions, accordingly. These change rates apply to a storage pod 110 in a single pod configuration, i.e. without an outer pod 300 arranged around the storage pod 110, as well as a dual pod configuration, i.e. a storage pod 110 stored within an outer pod 300.

[0115] The humidity drop and gas exchange without vertical purging (i.e. without a dedicated outlet interface 130 arranged opposite the inlet interface 120 with respect to the rerticle 200 stored within the storage pod 110) might be less uniform but will still be faster compared to diffusion based gas exchange as in prior art solutions.

[0116] It is to be noted, that the features as described in relation to certain embodiments of the invention comprising a specific combination of those features may also be used in different Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01

[0117] IDF3249 & 3250 06 May 2025

[0118] 15 combinations or alone, without departing from the general teaching of this invention, which is specifically defined in the appended claims.

Claims

1. Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01IDF3249 & 3250 06 May 202516Claims1 . Storage pod (110) for storage of a single reticle (200), especially an EUV reticle, the storage pod (110) comprising a base plate (112) and a cover (114) defining an interior space (111), the interior space (111) being configured and adapted to hold said single reticle, the storage pod (110) further comprising at least one gas inlet interface (120) for providing a purge gas (210) to the interior space (111), wherein a gas flow of the purge gas (210) into the interior space (111) is independent from an atmosphere surrounding the storage pod (110), and wherein the gas inlet interface (120) is configured to guide at least 90% of the purge gas (210) supplied to the gas inlet interface (120) into the interior space (111) of the storage pod (110).

2. Storage pod (110) according to claim 1 , wherein the gas inlet interface (120) comprises a pressure port (122), preferably located in the base plate (112), for providing the purge gas (210) to the storage pod (110) from outside the storage pod(110), an inlet orifice (126), preferably located in the cover (114), for allowing the purge gas (210) to enter the interior space (111), and a connection line (124) between the pressure port (122) and the inlet orifice (126) for guiding the purge gas (210) from pressure port (122) to the inlet orifice (126).

3. Storage pod (110) according to claim 1 or 2, further comprising at least one gas outlet interface (130) for withdrawing the purge gas (210) from the interior space(111) independent from the atmosphere surrounding the storage pod (110).

4. Storage pod (110) according to claim 3, wherein the at least one gas outlet interface (130) comprises a suction port (132), preferably located in the base plate (112), configured to allow application of a suction pressure below a pressure of the purge gas (210) at the gas inlet interface (120), an outlet orifice (136), preferably located in the base plate (112), configured to accept purge gas (210) from the interior space (111) and an outlet connection line (134) between the outlet orifice (136) and the suction port (132) for guiding the purge gas (210) accepted by the outlet orifice (136) to the suction port (132).Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01IDF3249 & 3250 06 May 2025175. Storage pod (110) according to any one of the preceding claims comprising a mechanism (116) for mechanically securing base plate (112) and cover (114) to one another.

6. Outer pod (300) configured to contain one storage pod (110) according to any one of the preceding claims within an inner volume of the outer pod (300), the outer pod (300) comprising at least one gas inlet terminal (320) configured to provide purge gas (210) to the at least one gas inlet interface (120) of the storage pod (110) within the inner volume of the outer pod (300), without providing the purge gas (210) to the inner volume of the outer pod (300).

7. Outer pod (300) according to claim 6 further comprising at least one gas outlet terminal (330) configured to accept purge gas (210) from the at least one outlet interface (130) of a storage pod (110) contained within the inner volume, when the storage pod (110) is configured at least according to claim 3.

8. Outer pod (300) according to claim 7, wherein the gas outlet terminal (330) is configured to guide the purge gas accepted or withdrawn from the storage pod (110) to an outer surface of the outer pod (300), particularly without allowing the purge gas to enter the inner volume of the outer pod (300) surrounding the storage pod (110).

9. Storage stocker configured to store a number of storage pods (110) according to any one of claims 1 to 5, wherein the storage pods (110) are stored in respective storage positions within the stocker, each of the storage pods (110) being contained within an outer pod (300) according to any one of claims 6 to 8 or stored in the storage position without any outer pod (300), the storage positions each being configured with a purge gas supply (420) to provide a purge gas to the at least one gas inlet interface (120) of the storage pod (110) and / or the gas inlet terminal (320) of the outer pod (300), respectively.

10. Storage stocker according to claim 9, comprising a securing mechanism adapted to physically secure each storage pod (110) within its respective storage position.Brooks Automation (Germany) GmbH DG1.DG23. DD174268 / 01IDF3249 & 3250 06 May 20251811. Dual pod including a storage pod according to any one of claims 1 to 5 and an outer pod according to any one of claims 6 to 8.

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