EUV reticle stocker and its operation method

Abstract

A clamping device (200, 500), a storage system (300, 600), and an operating method (400, 410) for an EUV reticle stocker are provided. The space required to store EUV reticles is significantly reduced while ensuring a high-quality storage environment for the stored EUV reticles. A further aspect of the present invention provides a stocker (700) for storing EUV reticles.

Description

[Technical Field]

[0001] The present invention relates to a stocker for EUV reticles and a method for operating said reticle stocker. [Background technology]

[0002] Photolithography processes are widely used as one of the key steps in the fabrication of integrated circuits (ICs) and other semiconductor-related devices and / or structures. However, as the dimensions of the features produced by such processes decrease, the importance of photolithography for producing miniature ICs or other devices and / or structures increases.

[0003] In photolithography, a geometric pattern is transferred from a photomask (commonly called a reticle) onto a substrate, such as a semiconductor wafer, using light, a photosensitive layer, and a subsequent etching step. The feature size of the reticle must be adapted to the desired feature size on the substrate, and the wavelength of the light used for pattern transfer must also be adapted to take into account the Rayleigh criterion.

[0004] To reduce the minimum achievable feature size, the use of extreme ultraviolet (EUV) radiation has been proposed. EUV radiation is electromagnetic radiation having a wavelength in the range of 5-20 nm, for example in the range of 5-10 nm.

[0005] Any contamination of the reticle can degrade the imaging performance of the photolithography process and, in more severe cases, may require the reticle to be replaced. Reticles are generally expensive, so reducing the frequency at which reticles must be replaced is advantageous. Furthermore, replacing a reticle is a time-consuming process, and the photolithography process must be supported while the reticle is being replaced, which can reduce the efficiency of the photolithography process, which is undesirable.

[0006] For EUV applications, particulate contamination with sizes less than 10 nm may be relevant, as well as chemical contamination due to, for example, adsorption of volatile organic compounds.

[0007] Therefore, reticles used for such EUV applications are typically stored in a storage stocker and retrieved when needed in association with a lithography exposure tool. Typically, the reticles are contained in a double-shell container (double-pod) with a so-called EUV outer pod (EOP) and an EUV inner pod (EIP).

[0008] Such double pods are described in more detail in, for example, US2019 / 0214287A1.

[0009] Because the acceptable level of particle contamination is extremely low, friction of the reticle against the container (which causes wear and thus particle generation) as well as friction between container components must be avoided. Therefore, typical EIPs are designed to house a single reticle with little chance of movement. The EIP also includes additional reticle-securing means for securing the reticle inside the EIP. To prevent contamination, EIPs are designed to allow a protective gas or vacuum to be applied to the reticle. To this end, orifices with filter material are typically provided to allow protective gas from the EIP to enter the area around the reticle contained in each EIP.

[0010] The EOP includes actuation means adapted to bias the reticle securing means of the EIP to a holding position, thereby securing the reticle inside the EIP when the EOP is attached to the EIP. The EOP also functions to secure the two pieces of the EIP relative to each other, typically to prevent friction-induced wear. Summary of the Invention [Problem to be solved by the invention]

[0011] It should be understood that EIP components can move relative to one another unless they are externally secured. To avoid friction-induced wear caused by such movement, EIPs traditionally provide such securing functionality to the EIP while also providing protection from the ambient atmosphere required during transport, for example, between a storage location and a process tool requiring the reticle for manipulation.

[0012] EOPs are rather bulky, resulting in a high space requirement or "footprint" for stockers that store EUV reticles. Furthermore, EOPs are made of polymeric materials that are also prone to wear and outgas volatile organic compounds. [Means for solving the problem]

[0013] The present invention attempts to solve these problems by providing methods, devices and systems having the features according to the independent claims. Advantageous embodiments and additional features are provided in the dependent claims and are discussed in the following description.

[0014] The present invention reduces the space required to store reticles while ensuring at least the same level of contamination and damage protection as that provided by conventional systems. Chemical contamination during storage due to outgassing EOPs is prevented, and mechanical damage protection for reticles stored in dual pods is improved. For example, while EOPs can easily be damaged during an earthquake, a device according to the present invention is not as easily broken, even under such difficult conditions, as will be understood from the following description.

[0015] An aspect to consider when developing such improved storage concepts is that it is highly undesirable to change the way reticles are presented to photolithography processing equipment, which is typically the most complex and expensive part of a semiconductor manufacturing facility.

[0016] Thus, since photolithography processing equipment is generally adapted to receive double pods, the means for providing conventional double pods to the photolithography processing equipment advantageously comprises a modified reticle stocker.

[0017] In one aspect of the present invention, a clamping device for an EUV Inner Pod (EIP) is provided, the EIP comprising two or more components and including or adapted and configured to include an EUV reticle, the clamping device being configured to secure the two or more components of the EIP and the reticle relative to one another and configured to only partially cover the EIP. For example, only a small portion, such as less than 90%, 80%, 75%, 50%, 25%, 20%, or 10% of the EIP's exterior surface, is covered by the clamping device according to the present invention. Thus, the clamping device can allow, for example, the atmosphere surrounding the clamping device to contact the EIP, thereby eliminating the need for highly complex supply means for, for example, protective gas.

[0018] It should be noted that the clamping device can also be used to clamp together the components of the EIP even if it does not hold a reticle; in this case, only the components of the EIP are secured relative to each other.

[0019] Advantageously, the clamping device is further configured to act on a retaining means of the EIP, the retaining means being configured to secure the reticle therein when acted on from outside the EIP to secure the reticle therein. Thus, securing the reticle within the EIP is performed via the clamping device acting on a retaining means provided on the EIP. This provides the advantage that existing systems can be used as is without the need for retrofitting, thus avoiding costly investments.

[0020] Advantageously, the clamping element is primarily made of a metallic material, preferably comprising at least 75%, 80%, 90%, 95%, or 99% of the total device volume and / or mass. This mitigates the aforementioned problem of chemical contamination due to outgassing of polymeric materials. This reduces the required amount of purging gas and the frequency of required reticle replacement. Other possible materials with similar advantages are, for example, polycarbonate (PC), polyethyl ether ketone (PEEK), or cycloolefin (co)polymer (COC / COP). The binding characteristics of these materials are, among other things, their low outgassing properties.

[0021] In an advantageous embodiment, the clamping device includes two clamping elements, including an upper clamping element and a lower clamping element, configured to be attachable to one another while receiving an EIP therebetween. Specifically, the movement required to assemble such a clamping device around an EIP is substantially perpendicular to a major surface of the EIP, and substantially no movement is required laterally relative to the EIP. This facilitates the assembly process and reduces the risk of friction-induced particle generation (wear).

[0022] Advantageously, the upper clamping element is configured to act on the retaining means of the EIP to secure the reticle therein, and thus can replace or mimic the clamping function traditionally performed by the EOP without the drawbacks of chemical contamination and spatial footprint.

[0023] In other embodiments, the clamping device includes a clamping element and one, two, or more fastening means, which are biased toward a closed position and configured to move to an open position, such that the clamping device can be attached to the EIP when the fastening means is in the open position and is configured to secure the EIP component and the reticle relative to one another when the fastening means is in and / or brought to the closed position. In other words, the clamping device is provided as a single clamping element with the fastening means, i.e., a one-piece clamping element. The fastening means acts on the underside of the EIP when the clamping device is attached to the EIP and on the upper side of the clamping element. In other respects, this single clamping element provides the same functionality as the upper clamping element described above. This one-piece embodiment is advantageous in terms of handling because only one piece is required to provide the same functionality. This piece is attached to the EIP from the upper side of the EIP. Therefore, fewer handling steps are required to attach the clamping device to the EIP compared to the two-piece embodiment described above.

[0024] Advantageously, the clamping device comprises an actuator configured to act on the retaining means when the clamping device is attached to the EIP.

[0025] Advantageously, the clamping device has an enclosed volume that is less than 130%, 120%, 110%, 105%, or even less than 100% of the enclosed volume of the EIP to which the clamping device can be attached.

[0026] Specifically, the clamping device has an enclosed volume that is less than 130%, 120%, 110%, or 105% of the enclosed volume of the EIP, thus providing a substantially smaller spatial footprint for storing reticles compared to storage in a dual pod comprising an EIP and an EOP. This may also reduce the required amount of purging gas mentioned above. The enclosed volume may be understood to represent, for example, the smallest possible cubic volume that completely encompasses the respective object.

[0027] Clamping devices according to some embodiments may include an information-carrying element, such as an RFID device or a visually detectable code, such as a bar code, QR code, or other form of 1D or 2D code. This provides the advantage that information about a reticle can be associated with a corresponding clamping device. Thus, for example, it may be possible to identify a stored reticle simply by identifying the clamping device associated with the reticle.

[0028] Furthermore, such information can be used for tracking purposes, for example, to count the number of storage operations performed using a given fastening device, which is useful for determining the appropriate time for cleaning or replacement procedures or functionality testing.

[0029] In some embodiments, sensors are included in the clamping device to monitor specific conditions during storage and handling, such as humidity, temperature, pressure, acceleration, or the concentration of specific chemical species in the storage atmosphere. This provides the advantage of being able to gain knowledge about the influencing factors experienced by reticles throughout their storage history, and can therefore improve the overall productivity of the manufacturing facility in which the present invention is used.

[0030] Such information may be stored and processed in a memory and / or processor provided in the tightening device or in components of a machine or tool that handles the storage system according to the invention.

[0031] In another aspect, the present invention provides a storage system including the clamping device described above and an EIP. The EIP includes two or more components configured to house an EUV reticle and includes a holding means configured to secure the reticle contained within the EIP when the holding means is acted upon from outside the EIP. The clamping device is attached to the EIP to secure the two or more components of the EIP relative to one another and acts on the holding means, thereby securing the reticle within the EIP. This can substantially avoid wear and minimize contamination of the reticle by particles in the relevant size range.

[0032] Typically, the retaining means is provided in the form of one or more pistons that penetrate one of the EIP components, each of which is resiliently biased to a retracted position and adapted to apply a normal force to the reticle when acted upon from outside the EIP, while the retaining means sealingly engages the EIP component upon penetration to protect the reticle stored within the EIP from contamination by contaminants from outside the EIP.

[0033] In preferred embodiments, the storage system has an enclosed volume that is less than 130%, 120%, 110%, or 105% of the enclosed volume of the EIP, thereby significantly reducing the space required to store reticles relative to conventional storage systems in the form of a dual pod with an EIP and an EOP.

[0034] Another aspect of the present invention provides a method of operating an EUV reticle stocker, the method including the steps of storing a reticle in the reticle stocker and retrieving the reticle from the reticle stocker, the storing step including moving a storage system according to the present invention containing the reticle to a storage position within the EUV reticle stocker, and the retrieving step including removing the storage system according to the present invention containing the reticle from the storage position, which reduces the space required to store the reticles compared to conventional storage methods.

[0035] In particular, the storing step further includes receiving, from outside the stocker, a double pod comprising an EUV outer pod (EOP) and an EIP containing an EUV reticle, where the EIP is entirely contained within the EOP, prior to the moving to the storage position step, opening the EOP, and attaching a clamping device to the EIP to secure the EIP components relative to one another and to act on retention means provided on the EIP to secure the reticle relative to the EIP to provide a storage system. In such an embodiment, the storage system is provided by the modified stocker itself, allowing the stocker to be directly utilized in connection with existing manufacturing processes without substantially modifying any process steps performed outside the stocker.

[0036] In a preferred embodiment, the step of receiving the duplex pod includes the steps of receiving the duplex pod at an exterior-facing side of an entrance terminal equipped with an airlock, opening a first shutter of the airlock, moving the duplex pod into the airlock, closing the first shutter, decontaminating the interior volume of the airlock, opening a second shutter of the airlock, moving the duplex pod through the second shutter to the interior-facing side of the entrance terminal, and closing the second shutter. In other words, the duplex pod passes through the airlock from the exterior-facing side to the interior-facing side of the entrance terminal, and decontaminates the interior volume of the airlock while the duplex pod is inside the airlock. This provides the advantage of avoiding contamination of the stocker.

[0037] The step of opening the EOP can include unlocking the EOP, removing the EOP from around the EIP, and storing the EOP in an EOP buffer stock. The EOP buffer stock is preferably separated from the storage location for the storage system described above to prevent cross-contamination from outside the EOP to the EIP. Therefore, stringent cleanliness requirements can be met while minimizing the space required to store reticles.

[0038] Preferably, retrieving the reticle after removing the storage system from its storage location further includes decoupling the clamping device from the EIP, assembling an EIP around the EIP to secure the EIP components and the reticle contained therein relative to one another, forming a double pod, and delivering the double pod outside the stocker, preferably through an airlock, to prevent contamination of the stocker atmosphere. This provides the advantage that standard double pods can be used using the facility's manufacturing processes, thus allowing conventional process equipment to take advantage of the improved storage conditions provided in connection with the present invention.

[0039] The EOPs used for this assembly can preferably be retrieved from the EOP buffer stock mentioned above. This offers the advantage of not requiring an EOP for each reticle stored, while still ensuring a timely supply of all reticles needed for the manufacturing process. In other words, the number of reticles stored can significantly exceed the number of EOPs provided. In other words, at any given time, only the reticles needed outside the stocker at that time require EOPs.

[0040] To prevent wear and corresponding particle generation, it is preferable to ensure that the reticle and / or EIP components do not move relative to each other while any step is being performed at a time when the reticle is not fixed relative to the EIP.

[0041] If the clamping device is equipped with the information transmitting elements described above, the method may advantageously include one or more steps in which the information transmitted by the clamping device is read, written, deleted, or modified, such that information regarding the identity of the reticle associated with the handled clamping device, the storage conditions experienced by the reticle, or other information may be used to control a reticle stocker or other tool, machine, or device to provide improved overall performance of the manufacturing facility.

[0042] The method can further include reading, receiving, or otherwise collecting information provided by one or more sensors optionally provided on the clamping device to monitor the history of storage conditions experienced by the reticle. This provides the advantage that reticles that are more likely to have quality defects can be inspected, for example, before being used in the manufacture of semiconductor products, thereby ensuring their integrity. Thus, the production of defective products is minimized.

[0043] In a further aspect of the present invention, there is provided a stocker for storing at least one EUV reticle, each of the at least one reticle being stored or adapted and configured within one respective EUV Inner Pod (EIP), the EIP comprising two or more EIP components secured relative to one another by clamping devices, the EIP comprising a retaining means configured, when acted upon from outside the EIP, to secure a reticle stored inside the EIP relative to the EIP, the clamping device acting on the retaining means to secure the reticle stored within the EIP, the stocker comprising a load port (also referred to in the language of this disclosure as an entry terminal) with an airlock and an assembler, each secured by one of the clamping devices, and each of The stocker includes a storage unit configured to store an EIP containing a reticle, and a handler configured to move the clamped EIP containing a reticle to and from a storage position within the stocker, an airlock configured to receive a double pod having an EUV outer pod (EOP) and an EIP containing a reticle from outside the stocker, the EOP acting on the holding means, an assembler configured to open the EOP without moving the EIP components and the reticle relative to each other, the assembler configured to attach and remove the clamping device to and from the EIP without moving the EIP components and the reticle relative to each other, and the assembler configured to assemble the EOP around the unclamped EIP.

[0044] Advantageously, the stocker further comprises an EOP buffer stock configured to store a number of EOPs in a controlled atmosphere using handling means, the handling means being configured to place EOPs into the EOP buffer stock and to retrieve EOPs from the EOP buffer stock.

[0045] In other words, the stocker is adapted to implement the method described above and thus to take advantage of the same advantages as those of the method described above.

[0046] The advantages and further aspects of the present invention will now be discussed in more detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0047] [Figure 1] 1A-1C illustrate two different embodiments of an EIP in relation to which the present invention can be implemented. [Figure 2] 1 shows a schematic perspective view of an advantageous embodiment of a clamping device according to the invention; [Figure 2A] 1A-1C are top views of the upper clamping element for two advantageous embodiments of a two-piece clamping device according to the present invention. [Figure 3] 1 shows a schematic perspective view of a preferred embodiment of a storage system according to the invention; FIG. [Figure 4A] 1 is a flow chart illustrating a preferred embodiment of a method of operation for an EUV reticle stocker in accordance with the present invention. [Figure 4B] 1 is a flow chart illustrating a preferred embodiment of a method of operation for an EUV reticle stocker in accordance with the present invention. [Figure 5A] 3 shows a schematic view of another advantageous embodiment of the clamping device according to the invention; [Figure 5B] 3 shows a schematic view of another advantageous embodiment of the clamping device according to the invention; [Figure 6] 1A and 1B are schematic diagrams showing a preferred embodiment of a storage system with a one-piece fastening device according to the present invention in perspective and plan views; [Figure 7] 1 is a diagram illustrating a preferred embodiment of a reticle stocker according to the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0048] Two embodiments A and B of a conventional EIP, generally designated 100, are shown in Figure 1. Each EIP 100 includes an upper component 110 and a lower component 120. The upper component 110 includes one or more orifices 112, a retaining means 114, and a pressure point 116.

[0049] The retaining means 114 is provided in the form of four pistons biased to a retracted position by elastic elements and sealingly connected to the upper component 110 by elastic sealing means to prevent particulate contaminants from entering the interior of the EIP.

[0050] Orifice 112 includes a filter material that also prevents particulate contaminants from entering the interior of the EIP while providing access for a purging and / or protective gas, such as nitrogen.

[0051] Pressure points 116 are provided to secure the two components 110, 120 to one another, and a retaining means is provided to secure the reticle to the inside of the EIP when applied from outside the EIP.

[0052] The lower component 120 may also include pressure points similar to the pressure points 116 of the upper component 110 .

[0053] In embodiment A of the EIP 100, the pressure point 116 is spatially separated from the retaining means 114, while in embodiment B, the retaining means 114 is provided in the same area as the pressure point 116 and extends through the pressure point 116.

[0054] 2 and 2A, a clamping device 200 that can be used in conjunction with embodiments A and B of the EIP 100 is shown generally.

[0055] The clamping device 200 comprises two elements 210, 220 made of sheet metal, one of which, the upper clamping element 210, is characterized by an orifice 212 that substantially corresponds in location to the one or more orifices 112 of the EIP and is configured to fit over the EIP 100. The portion of the surface of the EIP 100 that corresponds in location to the orifice 212 is referred to as "uncovered" in the language of this disclosure, while the portion of the surface of the EIP 100 that is in contact with the material surface of the clamping device, i.e., directly opposite or directly below the material surface of the clamping device, is considered to be "covered." Thus, according to the present invention, the clamping device 200 is configured to only partially cover the EIP 100. The orifice 212 can occupy more than 10%, 20%, 25%, 50%, 75%, 80%, or 90% of the surface area of the upper clamping element 210, among others. Additionally, a similar orifice may be provided in the lower clamping element 220 (not shown). Additionally, any laterally facing surfaces of the EIP 100 that do not correspond to either the upper clamping element 210 or the lower clamping element 220 are also considered "uncovered."

[0056] The second element 220 forming the lower clamping element is essentially flat and corresponds in size and shape as well as in profile to the upper clamping element 210 .

[0057] The upper and lower clamping elements 210, 220 can be attached to each other and are configured to receive and secure the EIP 100 therebetween when attached to each other. To that end, each of the upper and lower clamping elements includes a pressing means 216 configured to press against the pressure points 116 of the upper and lower components 110, 120 of the EIP 100, respectively, to secure the EIP components 110, 120 relative to each other.

[0058] Furthermore, in the case of embodiment A of the EIP 100, an actuator 214 is provided on the upper clamping element 210, and the actuator 214 is configured to act on the retaining means 114 of the upper component 110 of embodiment A of the EIP 100 when the clamping device 200 is attached to the EIP 100.

[0059] In a clamping device 200 adapted for use with embodiment B of the EIP 100, the pressing means 216 simultaneously perform the function of the actuator 214. Thus, each pressing means 216 also constitutes an actuator 214.

[0060] In either embodiment shown, the clamping device 200 secures a reticle contained within the EIP 100 relative to the EIP 100 by acting on the retaining means 114 of the EIP 100 .

[0061] The pressing means 216 and the actuator 214 are provided in the form of tongue-shaped notches and can be configured to apply a predetermined force to the pressure points 116 and the retaining means 114, respectively. Advantageously, the pressing means 216 is configured to apply a predetermined force to each of the pressure points 116. In a fastening device for use with embodiment A of the EIP 100, this force applied to the pressure points can be different from the predetermined force applied by the actuator 214 to the retaining means 114. The forces applied to the retaining means 114 and the pressure points 116 can thus be adapted to the required force needed to secure the respective components relative to one another. Generally, the force needed to secure a reticle within the EIP is less than the force needed to secure the upper component 110 relative to the lower component 120. The tongue-shaped notches forming the actuators 214 can therefore be longer and / or thinner than the notches forming the pressing means 216.

[0062] In a fastening device adapted to be used with embodiment B of EIP 100, it is also possible to apply different forces to pressure point 116 and retaining means 114, respectively, for example by providing an additional notch in the form of a tongue (not shown), so that a smaller force can be applied to retaining means 114 compared to the force applied to pressure point 116. In other words, although pressure point 116 and retaining means 114 in embodiment B of EIP 100 are close to each other, it is still possible to provide pressing means 216 and actuator 214 spaced apart from each other.

[0063] The upper clamping element 210 includes a fastening means 202 configured to fixedly attach the upper clamping element 210 to the lower clamping element 220 to provide the clamping device 200. In the example shown in Figures 2 and 2A, the fastening means 202 is provided in the form of a latch, although other forms of fastening means are possible as well.

[0064] 3 shows an assembled storage system 300 including an EIP 100 and a two-piece clamping device 200 having an upper clamping element 210 and a lower clamping element 220. The lower clamping element 220 is not visible in FIG. 3 because it is covered by the EIP 100.

[0065] 5A and 5B, a further advantageous embodiment of a fastening device 500 is shown diagrammatically in perspective and plan view.

[0066] 2 and 2A, the clamping device 500 includes only one clamping element having at least two fastening means 502. Furthermore, one or more pressing means 516 are provided, which are configured to press against respective pressure points 116 of the upper component 110 of the EIP 100 to secure the EIP components 110, 120 relative to one another. The fastening means 502 are configured to press against the upper side of the clamping element 500 and the lower side of the lower component 120 of the EIP 100 when the clamping device 500 is attached to the EIP 100. Similar to the clamping device 200, in the clamping device 500, an actuator 514 is provided to secure a reticle within the EIP 100. The securing of the reticle within the EIP 100 is achieved by interaction between the actuator 514 and the retaining means 114 of the EIP 100 when the clamping device 500 is attached to the EIP 100.

[0067] 5A and 5B is adapted for use with embodiment A of the EIP 100. However, it should be understood that a similar one-piece fastening device 500 could also be provided for embodiment B of the EIP 100.

[0068] 5A shows the fastening means 502 in the closed position. In this particular embodiment, the fastening means 502 has handling and locking elements, essentially in the form of leaf springs, provided on two sides of the clamping device 500. When attached to the EIP 100, the locking elements of the fastening means 502 perform the above-described function of pressing against the upper side of the clamping element and the underside of the bottom component 120 of the EIP 100.

[0069] 5B shows the fastening means 502 in an open position, in which the fastening means 502 is spaced from the clamping elements in such a way that the space between the two opposing fastening elements 502 of the clamping device 500 is large enough for the EIP 100 to move between them. Thus, with the fastening means 502 in the open position, the clamping device 500 can be attached to the EIP 100.

[0070] The securing means 502 in the form of a leaf spring are biased towards a closed position, so that in order to attach the securing means 502 to the EIP 100, a lateral force must be applied to the securing means 502 to bring them into the open position.

[0071] The clamping elements of the clamping device 500 are preferably made essentially of sheet metal, while the fastening means 502 may be provided in the form of a leaf spring of metal, plastic or any other suitable material or combination of materials.

[0072] The actuator 514 and the biasing means 516 are preferably provided in the form of a tongue-shaped notch, essentially as described above in connection with the embodiment of FIG.

[0073] When attaching the clamping device 500 to the EIP 100, the securing means 502 is forced into the open position. This can be accomplished by pulling the handling element of the securing means substantially laterally relative to the clamping device 500. The clamping device 500, with the securing means 502 held in the open position, is then placed on top of the EIP and pressed downward against the EIP using a preload force, causing the pressing means 516 and actuator 514 of the clamping device 500 to contact the pressing point 116 and holding means 114 of the EIP 100, respectively. Thus, when the preload force is applied, the interaction of the clamping device 500 and the EIP 100 immediately secures the EIP components 110, 120 and the reticle contained within the EIP 100 relative to one another.

[0074] The preload force is selected so that the fastening device 500 moves toward the EIP 100 in a direction perpendicular to its primary extension plane to an extent that the fastening means 502 can be released to the closed position without the fastening means 502 contacting any part of the EIP 100. Thus, as long as the preload force is applied, no friction is induced by the movement of the fastening means 502 to the closed position, thereby virtually preventing particle generation.

[0075] As long as the preload force is applied to the clamping device 500 , the fastening means 502 remains vertically spaced from the EIP 100 and from the top side of the clamping device 500 .

[0076] When the fastening means 502 reaches the closed position, the applied preload force is released, and the clamping device 500 therefore moves away from the EIP 100 until the fastening means 502 presses against the upper side of the clamping device and the underside of the lower component 120 of the EIP 100, thereby limiting further displacement of the clamping device 500 relative to the EIP 100.

[0077] Even after the preload force is removed from the top of the clamping device 500, the actuators 514 and the pressing means 516 still apply vertical clamping forces to the holding means 114 and the pressing points 116, respectively. These clamping forces are somewhat smaller than the preload force. However, the actuators 516 and the holding means 514, respectively, are designed so that the clamping forces provided by each of them are sufficient to secure the reticle within the EIP 100 and the components 110, 120 of the EIP 100 relative to each other. For example, the pressing means 516 of one clamping element 500 collectively or individually provide a vertical clamping force to the pressing points 116 in the range of 1 N to 100 N, preferably in the range of 5 N to 50 N, e.g., about 20 N ± 5 N, e.g., 17 N. This collective clamping force is preferably evenly distributed throughout the single pressing means 516. In the example shown, four pressure means 516 are provided in the clamping device 500, so that one-fourth of the aggregate clamping force is applied to each of the pressure points 116.

[0078] As discussed above, the clamping force applied to the reticle via the retaining means 114 is preferably less than the clamping force applied to the EIP components 110, 120 via the push points 116. For example, the clamping force applied to the retaining means 114 collectively or to each individual retaining means 114 can be selected from the range of 1 N to 100 N, preferably from the range of 5 N to 50 N, and can range, for example, from about 20 N ± 5 N, e.g., 17 N. This force is preferably distributed evenly across all of the provided actuators 514 in a manner similar to that described with reference to the push means 516.

[0079] As noted above, this one-piece fastening device 500 is not limited to use with embodiment A of the EIP 100. Different configurations are also provided in accordance with the present disclosure, such as configurations in which the one-piece fastening device 500 can also be used with embodiment B of the EIP 100. These embodiments of the fastening device 500 that can be used with embodiment B of the EIP 100 essentially correspond to the fastening device 200 that can be used with embodiment B of the EIP 100 described above, but are provided in the form of a one-piece fastening device similar to the form of the one-piece fastening device 500 described.

[0080] It should be appreciated that, compared to the two-piece clamping device 200, the one-piece clamping device 500 leaves substantially the entire lower component 120 of the EIP 100 uncovered, thereby covering less of the surface of the EIP 100. Thus, a clamping device 500 having an orifice the same size as the orifice 212 of the clamping device 200 would cover substantially less of the EIP 100. For example, when attached to the EIP 100, the clamping device 500 leaves at least 50%, 60%, 70%, 80%, or 90% of the EIP 100 uncovered. In some embodiments, the clamping device 500 (or 200) leaves at least the orifice 112 of the EIP 100 uncovered, thereby substantially unimpeding fluid access from the atmosphere surrounding the clamping device 500 (or 200) to the orifice 112.

[0081] 6 is a schematic diagram of a storage system 600 including the EIP 100 and clamping device 500 described above. The fastening means 502 of the clamping device 500 is in the closed position, and the pressing means 516 acts on the pressing point 116 to secure the EIP components 110, 120 relative to each other. The actuator 514 acts on the retaining means 114 to secure the reticle within the EIP 100.

[0082] As with two-piece clamping device 200, one-piece clamping device 500 adapted for use with embodiment B of EIP 100 also features a pressing means 516 that simultaneously functions as actuator 514. As with clamping device 200, actuator 514 of clamping device 500 can also be provided separately from pressing means 516, for example in the form of a tongue-shaped notch in pressing means 516 or in the form of a notch extending in the opposite direction to pressing means 516. These modifications, although not shown in the figures, provide the advantage that the force applied to pressing point 116 can be adjusted separately from the force acting on retaining means 114 of EIP 100.

[0083] 3 and 6, the clamping devices 200, 500 are small size clamping devices, and therefore the storage systems 300, 600 occupy essentially the same volume as the EIP 100 itself.

[0084] 4A, a flow diagram illustrates a preferred method of operation of reticle stocker 700 for storing reticles, generally referred to by the reference numeral 400. A corresponding reticle stocker is shown schematically in FIG.

[0085] This method will now be described with respect to the fastening device 200 discussed in connection with Figures 2 and 2A, although it should be understood that corresponding steps are performed when using the fastening device 500 to obtain the storage system 600 described above.

[0086] In step 401, a double pod comprising an EUV outer pod (EOP) 150 and an EIP 100 contained within the EOP 150 is received from outside the stocker 700. The double pod is received at the outward-facing side of an entrance terminal comprising an airlock 710 and passed through the airlock 710 to the inward-facing side of the entrance terminal. During passage through the airlock 710, the interior volume of the airlock 710 is decontaminated, thereby ensuring that the atmosphere inside the reticle stocker 700 is not adversely affected by receiving the double pod.

[0087] Decontamination of the airlock 710 may include evacuating the airlock 710, flushing the airlock 710 with a fluid such as a gas, especially an inert gas, and / or purging the airlock 710 with a fluid, especially an inert gas.

[0088] In step 402, the duplex pod is opened. Opening the duplex pod, in this example, involves unlocking EOP 150, removing it from its position surrounding EIP 100, and moving it to EOP buffer stock 750 where it can be stored until needed again. Once EOP 150 is removed from EIP 100, pressure points 116 and retention means 114 are no longer acted upon. Thus, EIP components 110, 120, and the reticles contained therein, are no longer secured relative to one another.

[0089] In step 403, the tightening device 200 is attached to the EIP 100, thereby providing the storage system 300 shown in FIG. 3 . Attaching the tightening device 200 is performed, inter alia, by placing the EIP 100 over the lower tightening element 220, then covering the EIP 100 with the upper tightening element 210, and attaching the lower and upper tightening elements to each other. Placing the EIP 100 over the lower tightening element 220 and covering the EIP 100 with the upper tightening element 210 is preferably performed in a manner that applies essentially only vertical forces to the EIP 100 and avoids torsional and lateral forces. Once attached to the EIP 100, the tightening device 200 essentially restores or mimics the securing function performed by the EOP 150 prior to opening the dual pod.

[0090] If a one-piece clamping device 500 is used, step 403 of attaching the clamping device is performed in a slightly different manner. In such a case, the fastening means 502 of the clamping device 500 is forced into an open position, as shown in FIG. 5B . The clamping device 500 is then moved over the EIP 100 and pressed against the EIP 100 in a direction perpendicular to the primary extension plane of the clamping device 500 (the "vertical direction") using a defined preload force. The fastening means 502 is then released to a closed position, releasing the preload force from the clamping device 500. This forms the storage system 600 described above.

[0091] In step 404, the storage system 300, 600 is moved to a storage position within the reticle stocker.

[0092] All of the steps, particularly steps 402 and 403, are performed in a manner such that the reticle contained with EIP 100 does not move relative to EIP 100 to prevent friction-induced particle generation as explained above.

[0093] A preferred method of operating the reticle stocker to retrieve a reticle is shown in flow diagram form in FIG. 4B and is generally referenced by the numeral 410 .

[0094] In step 411, the storage system 300 is removed from its storage location.

[0095] In step 412, the clamping device 200 is removed from the EIP 100 to disassemble the storage system 300. To do so, the upper and lower clamping elements 210, 220 are separated from one another and the upper clamping element 210 is lifted from the EIP 100, thereby releasing the pressure point 116 and the retention means 114. At that point, fixation of the reticle within the EIP 100 is no longer effective.

[0096] If storage system 600 is to be disassembled, step 412 is again performed in a slightly modified manner, with clamping device 500 first being removed from EIP 100 by applying a preload force to clamping device 500 so that fastening means 502 is no longer in contact with the EIP 100 or the top side of clamping device 500. Fastening means 502 is then forced to an open position and the preload force is released. Clamping device 500 is then lifted from EIP 100, thereby releasing pressure point 116 and retention means 114.

[0097] If one-piece clamping device 500 is used, steps 403 and 412 can be performed without any movement of EIP 100. This can be accomplished by either leaving EIP 100 on the lower component of EOP 150 when clamping device 500 is attached to EIP 100, or by placing EIP 100 on the lower component of EOP 150 before detaching clamping device 500, respectively. This is particularly advantageous because it effectively prevents relative movement of EIP components 110, 120 and the reticle, respectively.

[0098] In step 413, EOP 150 is retrieved from EOP buffer stock 750 and assembled around EIP 100 to provide a double pod. Once the double pod is fully assembled, the EOP provides the securement function performed by fastening device 200 during storage.

[0099] In step 414, the duplex pods formed in step 413 are delivered outside of stocker 700. This may involve passing the duplex pods through the above-mentioned airlock 710 to the exterior-facing side of the entry terminal. Airlock 710 may be purged or flushed while the duplex pods are passing through to prevent contaminants from entering the entry terminal.

[0100] 7, reticle stocker 700 includes the previously mentioned airlock 710, an assembler 720 configured to perform steps 402, 403, 412, and 413 of methods 400, 410 described above, an EOP buffer stock 750 capable of storing multiple EOPs 150, and a storage unit 740 capable of storing storage systems 300, 600 at multiple storage locations 742. A handler 730 is provided in stocker 700 for moving storage systems 300, 600 to and from their respective storage locations 742.

[0101] Note that the number of storage locations 742 can substantially exceed the number of EOPs 150 that can be stored in EOP buffer stock 750. As explained above, only reticles that are needed outside stocker 700 require EOPs 150. Therefore, a (small number of) EOPs 150 can be stored in EOP buffer stock 750, thus allowing double pods to be assembled when reticles are needed. However, it is not necessary to store an EOP 150 for every reticle stored in storage unit 740, since typically not all reticles will be required at the same time.

[0102] 2, 2A and 5A, the tightening device 200, 500 additionally comprises a logging element 218, 518 (shown schematically) that comprises an identification device, such as an RFID device, and one or more sensors. The RFID device 218, 518 is an information transmitting element that comprises an identification number, so that an individual tightening device 200, 500 can be distinguished from other tightening devices 200, 500 by reading the RFID device 218, 518.

[0103] The one or more sensors included in the logging element 218, 518 are configured to detect or measure, for example, the temperature, the composition of the atmosphere surrounding the clamping device 200, 500, the pressure, and / or the acceleration acting on the clamping device 200, 500. The logging element 218, 518 in this example is further configured to store the readings of the one or more sensors and / or make these readings available for further processing.

[0104] If the clamping device 200, 500 is equipped with, for example, an RFID device 218, 518, the method 400 can include providing an association between a reticle stored in combination with a particular clamping device 200, 500 and an identification number provided on the RFID device 218, 518 of the clamping device 200, 500 being used. This association can be stored, for example, in a central memory of the reticle stocker and / or in a central computing device of the manufacturing facility. This provides the advantage that reticles can be identified by the clamping device 200, 500 being used for their storage, and therefore while still securely contained within their respective EIPs 100.

[0105] The method may further include collecting data from one or more sensors and using this data, for example, to evaluate whether further action, such as inspection of the retrieved reticle, is required.

[0106] Advantageously, method 410 then uses this RFID device 218, 518 of the clamping device 200, 500 to retrieve the reticle associated with the clamping device 200, 500, thereby providing a verification mechanism. For example, a given reticle's storage location 742 in stocker 700 can be used to identify the reticle to be retrieved from stocker 700. When retrieving a reticle from that storage location 742, the RFID device 218, 518 of the clamping device 200, 500 can be read, and the association of the clamping device's 200, 500 identification number with the stored reticle can be checked to verify that the correct reticle has been retrieved. If the identification of the reticle stored in a particular storage location differs from the reticle associated with the clamping device 200, 500, an identification procedure can be triggered and an alarm signal can be generated, so that the reticle is not used by production before its identification is verified. This provides the advantage of higher overall reliability of reticle identification.

[0107] Another advantage of this association of reticles with their respective clamping devices 200, 500 is that they can still be identified if they are randomly removed from their respective storage locations. This may occur, for example, during an earthquake or similar uncontrollable event. In such a situation, with conventional methods and systems, the reticles might have been removed from their respective EIPs for identification, or the conventional storage system might even have been destroyed. Thus, the invention disclosed herein provides a safer storage environment with improved traceability for EUV reticles.

Claims

1. A clamping device for an EUV inner pod (EIP), the EIP (100) comprising two or more components and including an EUV reticle, the clamping device (200, 500) comprising: configured to fix the two or more components (110, 120) of the EIP (100) and the reticle relative to one another; and configured to only partially cover the EIP (100); The fastening device (200, 500) an upper clamping element (210) and a lower clamping element (220), the upper clamping element (210) and the lower clamping element (220) being configured to be attachable to one another while housing the two or more EIP components (110, 120) therebetween; or, a clamping element having one, two, or more fastening means (502), the fastening means (502) being biased toward a closed position and configured to move to an open position, the clamping device (500) being attachable to an EIP (100) when the fastening means (502) are in the open position and configured to secure the EIP components (110, 120) and the reticle relative to one another when the fastening means (502) are in the closed position; Tightening device.

2. 2. The clamping device (200, 500) of claim 1, further configured to act on a retaining means (114) of the EIP (100), the retaining means (114) being configured to secure the reticle therein when acted on from outside the EIP (100) to secure the reticle within the EIP (100).

3. A tightening device (200, 500) as described in claim 2, wherein one tightening element (210) is provided with an actuator (214, 514) configured to act on the retaining means (114) when the tightening device (200, 500) is attached to the EIP (100).

4. A tightening device (200, 500) as described in claim 1 or 2, comprising at least 75%, 80%, 90%, 95% or 99% metallic material in terms of mass and / or volume of the tightening device (200, 500).

5. A tightening device (200, 500) described in any one of claims 1 to 4, having an enclosed volume of less than 130%, 120%, 110%, 105% or 100% of the enclosed volume of an EIP (100) to which the tightening device (200, 500) can be attached.

6. An information transmission element configured to identify the tightening device (200, 500); temperature sensors, pressure sensors, a concentration sensor configured to detect or measure the concentration of one or more chemicals in the atmosphere surrounding the fastening device (200, 500); and / or Acceleration sensor a logging element (218, 518) comprising one or more components including:

6. The tightening device (200, 500) of claim 1, wherein the logging element is configured to store and / or make available information generated using the one or more components of the logging element (218, 518).

7. A storage system (300, 600) comprising a clamping device (200, 500) according to any one of claims 1 to 6 and an EUV Inner Pod (EIP) (100), wherein the EIP (100) is configured to house an EUV reticle; and two or more components (110, 120) and a holding means (114) configured to secure the reticle when the holding means (114) is acted upon from outside the EIP (100); The fastening device (200, 500) can be attached to the EIP (100) to secure the two or more components (110, 120) relative to one another and act on the retaining means (114), storage system (300, 600).

8. A storage system (300, 600) as described in claim 7, having an enclosed volume that is less than 130%, 120%, 110% or 105% of the enclosed volume of the EIP (100).

9. A method of operating an EUV reticle stocker (700), comprising the steps of: storing (400) an EUV reticle in said reticle stocker; and retrieving (410) a reticle from said reticle stocker (700), the storing step (400) comprising the step of moving (404) a storage system (300, 600) according to claim 7 or 8 containing a reticle to a storage position (742) within the EUV reticle stocker (700); 9. The method of claim 7, wherein the recovering step includes removing the reticle from its storage location. Including, method.

10. The step of storing (400) includes, before the step of moving (404) to a storage location (742): receiving (401) a double pod comprising an EUV outer pod (EOP) (150) and an EIP (100) containing an EUV reticle from outside the stocker (700), the EIP (100) being entirely contained within the EOP (150); Opening the EOP (402); Attaching (403) a clamping device (200, 500) to the EIP (100) to secure the EIP components (110, 120) relative to each other and to act on a retaining means (114) included in the EIP (100) to secure the reticle relative to the EIP (100) to provide the storage system (300, 600); The method of claim 9 further comprising:

11. The step (401) of receiving the double pod comprises: receiving said double pod at the outward-facing side of an entrance terminal equipped with an airlock (710); opening a first shutter of said airlock (710); moving the double pod into the airlock (710); closing the first shutter; decontaminating the interior volume of said airlock (710); opening a second shutter of said airlock (710); moving the dual pod through the second shutter to an inward-facing side of the entrance terminal; closing the second shutter; The method of claim 10, comprising:

12. The step (402) of opening the EOP (150), unlocking the EOP (150); removing the EOP (150) from around the EIP (100); storing said EOP (150) in an EOP buffer stock (750); 12. The method of claim 10 or 11, comprising:

13. The recovering step (410) after the removing step (411) from the storage location (742) comprises: disconnecting (412) the fastening device (200, 500) from the EIP (100); Assembling (413) an EOP (150) around the EIP (100) to secure the EIP components (110, 120) and the front reticle contained within the EIP (100) relative to each other, forming a double pod; delivering (414) the dual pod outside the stocker (700); 13. The method of claim 10, further comprising:

14. A stocker (700) for storing at least one EUV reticle, each of the at least one reticle being stored in a respective EUV Inner Pod (EIP) (100), the EIP (100) comprising two or more EIP components (110, 120) secured to one another by clamping devices (200, 500), the EIP (100) comprising holding means (114) configured to secure the reticle stored inside the EIP (100) to the EIP (100) when acted upon from outside the EIP (100), the clamping devices (200, 500) acting on the holding means (114) to secure the reticle stored within the EIP (100), the stocker (700) comprising: a loading port with an airlock (710) and an assembler (720); storage units (740) each secured by one clamping device (200, 500) and configured to store EIPs (100) each containing one reticle at a respective storage location (742); a handler (730) configured to move the clamped EIP (100) containing the reticle to and from respective storage locations (742) within the storage unit (740) of the stocker (700); Equipped with the airlock (710) is configured to receive a double pod comprising an EUV outer pod (EOP) (150) and an EIP (100) containing a reticle from outside the stocker (700), the EOP (150) acting on the holding means (114); and The assembler (720) is configured to open the EOP (150) without moving the EIP components (110, 120) and the reticle relative to each other, the assembler (720) is configured to attach the clamping devices (200, 500) to the EIP (100) and remove the clamping devices (200, 500) from the EIP (100) without moving the EIP components (110, 120) and the reticle relative to each other, and the assembler (720) is configured to assemble the EOP (150) around the unclamped EIP (100). Stocker (700).

15. A stocker (700) as described in claim 14, further comprising an EOP buffer stock (750) configured to store a number of EOPs (150) in a controlled atmosphere using handling means, the handling means configured to place EOPs (150) in the EOP buffer stock (750) and to retrieve EOPs (150) from the EOP buffer stock (750).

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