Stocker pod for storing semiconductor manufacturing items, method and stocker

Abstract

A stocker pod (100) for storing semiconductor manufacturing items, the stocker pod (100) comprising at least two components (110, 120) having at least one fixture (130) integrally formed with at least one of the at least two components (110) of the stocker pod (100), the fixture (130) being configured to secure the two or more components (110, 120) of the stocker pod (100) to one another.

Description

[Technical field]

[0001] The present invention relates to tools, methods and apparatus for storing semiconductor manufacturing items. [Background technology]

[0002] 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. However, as the dimensions of features produced by such processes decrease, the importance of photolithography for the manufacture of miniature ICs or other devices and / or structures increases.

[0003] In photolithography, a geometric pattern is transferred from a photomask (usually called a reticle) to a substrate, such as a semiconductor wafer, by the use of light, a photosensitive layer, and a subsequent etching step. Depending on the desired feature size of the substrate, the feature size of the reticle must be adapted, taking into account the Rayleigh criterion, as well as the wavelength of the light used to transfer the pattern.

[0004] To reduce the minimum achievable feature size, it has been proposed to use extreme ultraviolet (EUV) radiation, which 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, can require replacement of the reticle. Reticles are typically expensive, and therefore any reduction in the frequency with which they must be replaced is advantageous. Furthermore, replacing a reticle is a time-consuming process during which the photolithography process must be paused, thereby undesirably reducing its efficiency.

[0006] For EUV applications, not only particulate contamination with diameters below 10 nm is of concern, but also 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 housed in a double-shell container (double-pod) comprising a so-called EUV outer pod (EOP) and an EUV inner pod (EIP).

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

[0009] Since the acceptable level of particle contamination is extremely small, friction of the reticle against the container (leading to wear and thus particle generation) as well as friction of the container components against each other must be avoided. Therefore, typical EIPs are designed to accommodate one reticle in such a way that it has only very limited possibilities for moving within it. They are also equipped with additional reticle fixing means to fix the reticle inside the EIP. To prevent contamination, the EIPs are designed to allow a protective gas or vacuum to be applied to the reticle. To that end, an orifice with a filter material is typically provided for the protective gas to enter from the EIP into the surroundings of the reticle contained in the respective EIP.

[0010] The EOP includes actuation means adapted to bias the reticle securing means of the EIP into a retaining position, thereby securing a reticle within the EIP when the EOP is attached to the EIP, and typically also functions to secure two EIP pieces together to prevent wear caused by friction.

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

[0012] EOPs are fairly bulky, leading to high space requirements or "footprint" for stockers that store EUV reticles. Furthermore, they are made of polymeric materials that are also prone to wear and outgassing of volatile organic compounds. Summary of the Invention

[0013] The present invention seeks to solve these problems by providing a method, an apparatus and a device 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 makes it possible to reduce the space required to store reticles while ensuring at least the same level of contamination and damage protection provided by conventional systems. Chemical contamination during storage from outgassing EOPs is prevented and mechanical damage protection is improved over storing reticles in double pods. For example, EOPs can be easily damaged during earthquakes, but the device according to the invention is less likely to break even under such difficult conditions, as will be understood from the following description.

[0015] Aspects that need to be considered when developing such an improved storage concept include the high desirability of altering the way in which reticles are presented to the photolithography process equipment, which is typically the most complex and costly part of a semiconductor manufacturing facility.

[0016] Thus, since photolithographic processing tools are typically adapted to accommodate dual pods, a means for providing a conventional dual pod to a photolithographic processing tool would advantageously comprise an improved reticle stocker.

[0017] In one aspect, the present invention provides a stocker pod for storing semiconductor manufacturing items, the stocker pod including at least two components with at least one fixture integrally formed with at least one of the at least two components of the stocker pod and configured to secure the two or more components of the stocker pod to one another, the semiconductor manufacturing item being, inter alia, one of the group consisting of a wafer, a portion of a wafer, and a reticle, in particular an EUV reticle.

[0018] By providing specific stocker pods, the contamination level of each stocker can be significantly reduced compared to conventional storage methods where goods are stored in pods that are also used outside the stocker. The stocker pods do not need to leave the stocker during normal operation and therefore cannot transport contaminants from outside the stocker to the stocker. However, it is important to provide the same protection for the molded articles during storage as in the conventional storage conditions described above. The fasteners that secure the stocker pod components to each other keep the protective shell of the stocker podded around the articles, even in such events as earthquakes, or even simple power outages, so that the articles are not damaged in such situations.

[0019] The at least one fixture is preferably configured to be biased towards a closed position and moved to an open position, the at least two components are configured to be attachable to one another to form a stocker pod when the at least one fixture is in the open position, and the at least one fixture is configured to secure the at least two components relative to one another when in the closed position, which aids towards the purpose of protection in situations where external fixation is not provided, such as the power outage and potentially necessary evacuation scenarios discussed above.

[0020] At least one fixture is preferably configured to be locked in an open position to overcome a bias towards the closed position. This is advantageous for example to use existing equipment in connection with the proposed stocker pod that is not configured to open the fixture. Examples of such equipment may include a cleaning tool that may be adapted to clean the inner pod of the double pod mentioned above, and in such an advantageous configuration may also be used to clean the stocker pod.

[0021] The at least one locking device is advantageously provided in the form of a latch provided on one of the at least two components and an engagement member engageable with a latch provided on the other of the at least two components. This is a particularly robust option for providing the locking device. For example, the engagement member may be slidable along the side of the component on which it is provided or in a direction perpendicular to the side of the component on which it is provided (e.g. if hingedly attached to the component). The bias towards the closed position may be provided by a spring element, a magnet, etc.

[0022] The at least two components, when secured together, preferably form a gap between each other. This aids in purging around the article, thereby further increasing the level of cleanliness and contamination protection. This is somewhat counterintuitive, since sealing against the surrounding atmosphere is normally considered essential for contamination protection. However, since the stocker pod of the present invention is only used inside the stocker during normal operation, the increased purge efficiency provides a greater cleanliness advantage than preventing the stocker atmosphere from flowing around the article.

[0023] In particular, the gap extends over a portion of at least one side of the stocker pod, including in the range of 2% to 50%, particularly 5% to 30%, and preferably 10% to 25% of the area of ​​at least one side of the stocker pod, which provides for a largely undisturbed flow without unduly compromising the stability of the overall stocker pod.

[0024] The gap preferably extends over a lateral portion of at least one side of the stocker pod between 20% and 90%, in particular between 30% and 85%, preferably between 50% and 80%, of the width of the at least one side. The gap can also extend up to 100% of the width of the side, where necessary connections between components such as support pins etc. can be neglected in terms of the lateral extension. The gap can extend over a vertical portion of at least one side of the stocker pod between 5% and 80%, in particular between 15% and 70%, preferably between 20% and 50% of the height of the at least one side. This provides an opening with a favorable geometry in terms of flow dynamics.

[0025] In an advantageous embodiment, the stocker pod has a height in the range of 10-30 mm, such that the gap may have a height in the range of 0.5 mm-24 mm, in particular 1.5 mm-21 mm, preferably 2 mm-15 mm. This allows the flow of purge gas to and / or from the stocker pod to be largely undisturbed. Turbulence is undesirable as it may prevent efficient transport of contaminants from the articles.

[0026] In some advantageous embodiments, a tortuous path is formed between at least two components of the stocker pod in at least one portion of at least one side not defined by the gap described above, which provides the advantage of preventing particles from entering the interior volume while still allowing purge gas to exit through a tortuous path through each side of the stocker pod.

[0027] The stocker pod advantageously comprises at least 75%, 80%, 90%, 95% or 99% and up to 100% metallic material by its mass and / or volume, which prevents chemical contamination of the articles by, for example, outgassing of polymeric materials.

[0028] Advantageously, the stocker pod further includes a retainer configured to secure the article to the stocker pod at least when the fastener is in the closed position, thereby preventing wear-induced particle generation during internal motion events, such as moving the stockers in and out of their respective storage positions, as well as during external motion events, such as earthquakes.

[0029] In another aspect, the invention provides a method of storing semiconductor manufacturing articles comprising housing the articles in a stocker pod as described and storing the stocker pod in a storage location of a reticle stocker, the method benefiting from the described advantages of the stocker pod in a corresponding manner.

[0030] Advantageously, the method further comprises housing an EUV double pod comprising an EUV inner pod and an EUV outer pod, housing the article, opening the outer pod and the inner pod to retrieve the article from the inner pod, and positioning the stocker pod around the article retrieved from the inner pod, which has the advantage that existing routines of the semiconductor manufacturing facility can be used without adaptation with corresponding effects on investment costs.

[0031] In particular, the method includes moving the fixture to an open position, opening the stocker pod, placing the article in the stocker pod, closing the stocker pod, and releasing the fixture, which biases the fixture to a closed position and, when released, moves it to the closed position. Note that the fixture does not have to be locked in the open position to be released, but only needs to be held in the open position, for example by a handler. This corresponds to the predetermined movement of the stocker pod described above.

[0032] Another aspect of the invention provides a stocker for storing semiconductor manufacturing articles, in particular EUV reticles, configured to carry out the method as described and to hold a number of stocker pods in a storage location in the stocker, the stocker benefiting mutatis mutandis from the same advantages as the stocker pods. [Brief description of the drawings]

[0033] [Figure 1] FIG. 1 shows diagrammatically in a top plan view an advantageous embodiment of a stocker pod according to the invention. [Diagram 2] FIG. 2 shows diagrammatically an advantageous embodiment of a stocker pod according to the invention in use in a side plan view. [Diagram 3] FIG. 3 shows a schematic representation of the assembly and / or disassembly of the embodiment of FIG. 2 in a front plan view. [Figure 4] FIG. 4 is a schematic diagram illustrating, in side plan view, the operation of a fixture of one embodiment of a stocker pod according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] In the description of the figures, like elements are referred to with the same reference numerals and the respective descriptions are not repeated for every figure for reasons of brevity.

[0035] In Figure 1 an advantageous embodiment of a stocker pod according to the invention is shown diagrammatically in a top plan view and is generally designated by the reference numeral 100. Figure 2 shows the same embodiment in use in a schematic side plan view. In figures depicting substantially symmetrical arrangements, not all identical elements are numbered so as not to obstruct the view of the depicted features.

[0036] The stocker pod 100 in the illustrated embodiment comprises an upper component (cover) 110 and a lower component (base) 120 (covered by the upper component and therefore not visible in FIG. 1).

[0037] The upper component 110 includes a handling extension 140 extending laterally from the stocker pod 100 and configured to be handled by a handler, such as an end effector of a robot operating on the reticle stocker, to store and retrieve reticles to and from their respective storage locations.

[0038] The stocker pod 100 further comprises fasteners 130 for securing the upper and lower components 110, 120 of the stocker pod 100 together. In the illustrated example, four fasteners 130 are provided along each side of the stocker pod 100 in the form of respective slidable latches. Each latch engages with an engagement member 134 provided on the lower component, as seen in FIG. 3. Alternatively, the latch provided on the lower component 120 may engage with an engagement member 134 provided on the upper component 110. It should be understood that in general the number of latches or fasteners is not limited to the exact value of four, and more or less fasteners may be provided.

[0039] In FIG. 2, the stocker pod 100 is shown in use in a storage position of the stocker. A purge gas, e.g., dry air, synthetic air, nitrogen, argon or any other suitable gas, is provided through the back wall 200 of the storage position via an outlet 210. The upper and lower components 110, 120 form a gap 160 between them through which the purge gas enters the stocker pod 100 and purges an interior volume of the stocker pod 100, shown by the dotted line. The interior volume contains a semiconductor manufacturing article, e.g., an EUV reticle 150. The purge gas flows around the reticle 150, as shown by the thick arrow. The purge gas can exit the stocker pod through the gap 161 on the side facing the back wall 200 of the storage position and on the opposite side. This configuration provides a substantially uniform flow of purge gas throughout the reticle 150.

[0040] The gaps 160, 161 at either end may be open or may contain filters and / or have obstructions 165 to affect the flow of purge gas. For example, the spaces may contain obstructions 165 in the form of one or more plates with slots or perforations. Such plate(s) may be attached to the upper and / or lower components such that when the components are attached together and purge gas is applied, the gas flows through the plates. The slots or holes in the plates may be arranged to produce a desired purge gas flow regime and / or velocity.

[0041] In Fig. 3, the assembly and further details of the stocker pod 100 are illustrated. The upper component 110 with the latch 130 moves vertically towards the lower component 120 to close the stocker pod 100. One or more guide pins 122, here provided on the lower component 120 (with corresponding guide pin receiving openings in the opposite component 110) aid in the correct alignment of the two components 110, 120. Each of the components 110, 120 presents a recess in its front and back wall, whereby a gap 160 is formed in either the front or back wall when the two components 110, 120 are attached to each other. This forms the flow path for the purge gas as described above in relation to Fig. 2. In the remaining sidewall of the stocker pod 100 (the wall carrying the latch 130), a tortuous path is formed by a protrusion 112 extending from the top component 110 along said sidewall towards the bottom component 120 and a corresponding recess 124 in the bottom component 120, as shown in the inset of Figure 3, in accordance with the embodiment shown in Figure 3. This tortuous path prevents particles generated by operation of the latch 130 from entering the interior volume of the stocker pod 100.

[0042] The tortuous path 112, 124 described above can extend along most of the length of the sidewall or only along one or more portions of the sidewall length. If it extends only along one or more portions, the portion not including the tortuous path may be sealed or open (in a manner similar to the gaps 160, 161). In some embodiments, the area near or adjacent to the fixture 130 may be tightly sealed and the area further away from the fixture 130 may include the tortuous path. In other embodiments, the area near or adjacent to the fixture 130 may include the tortuous path 112, 124 and the area further away from the fixture 130 may be open (in a manner similar to the gap 160). In still other embodiments, the entire length of the sidewall is tightly sealed to prevent gas and / or particles from entering the stocker pod 100 through the sidewall. The tortuous paths 112 , 124 and / or tightly sealed portions proximate the fixture 130 prevent particles generated by the operation of the fixture 130 from entering the interior volume of the stocker pod 100 .

[0043] In Fig. 4, the operation of the latches 130 is illustrated in more detail. Each of the latches 130 is provided with a biasing element 132, e.g., a spring such as a coil spring 132, which biases the latch to a closed position, as shown in the top diagram of Fig. 4. In the embodiment shown in Fig. 4, the latches comprise the lower component 120 and the engagement member 134 is provided on the opposite (upper) component 110. To open or close the stocker pod 100, the latches 130 are brought to an open position in which the engagement member 134 disengages from the respective latch 130, as shown in the center diagram of Fig. 4. In such a situation, the force of the strain coil spring 132 acts in the direction of the closed position. This means that the latches 130 cannot be inadvertently opened, since once closed, they remain in the closed position until they are forced into the open position.

[0044] The bottom view of FIG. 4 shows a special situation where the latch 130 is locked in the open position, i.e. disengaged from the engagement member 134. The locking in the open position is provided, for example, by a retainer 136 engageable with a recess 138 provided in the latch 130. When engaged with the recess 138 of the latch 130, the retainer 136 holds the latch 130 with a force that exceeds the biasing force of the coil spring 132 so that the latch 130 remains in the locked open position. This configuration is advantageous for situations or operations where the stocker pod 100 needs to be handled by a tool, whereby the latch 130 itself cannot be opened. In preparation for use in such a tool, the latch 130 of the stocker pod 100 is brought to the locked open position before providing the stocker pod 100 to the respective tool. For example, a cleaning machine adapted to clean a typical inner pod of an EUV double pod as described at the beginning of this description can also be used for cleaning the stocker pod 100 of the present invention. However, a typical inner pod does not include such a latching mechanism and therefore the cleaning tool may not be able to process the latch 130. Thus, the latch 130 is locked in the open position and thus handling the cleaning tool may include the same steps as cleaning a typical inner pod.

Claims

1. A storage pod (100) for storing semiconductor manufacturing articles (150), wherein the storage pod (100) comprises at least two components (110, 120) having at least one fastener (130, 134), the at least one fastener (130, 134) being integrally formed with at least one of the at least two components (110, 120) of the storage pod (100), the fastener (130, 134) being configured to fix two or more of the components (110, 120) of the storage pod (100) to each other, and when the at least two components (110, 120) are fixed to each other, a gap (160, 161) is formed between them on at least one side of the storage pod (100).

2. The stocker pod (100) according to claim 1, wherein the at least one fastener (130, 134) is configured to be biased toward a closed position and moved toward an open position, the at least two components (110, 120) are configured to be attachable to each other to form the stocker pod (100) when the at least one fastener (130, 134) is in the open position, and the at least one fastener (130, 134) is configured to fix the at least two components (110, 120) toward each other when in the closed position.

3. The stocker pod (100) according to claim 1 or 2, wherein at least one of the fasteners (130, 134) is configured to be lockable in the open position so as to overcome a bias toward the closed position.

4. The stocker pod (100) according to any one of claims 1 to 3, wherein the at least one fastener (130, 134) comprises a latch (130) on one (110) of the at least two components (110, 120) and an engaging member (134) provided on the other (120) of the at least two components (110, 120) and engaging with the latch (130).

5. The storage pod (100) according to claim 1, wherein the gap (160, 161) extends over a portion of at least one side of the storage pod (100), including a range of 2% to 50%, particularly 5% to 30%, preferably 10% to 25%, of the region of at least one side of the storage pod (100).

6. The storage pod (100) according to claim 5, wherein the gap (160, 161) extends across the lateral portion of at least one side of the storage pod (100) and reaches between 20% to 90% or 100%, particularly 30% to 85%, preferably 50% to 80%, of the width (102) of at least one side, and / or the gap (160) extends across the vertical portion of at least one side of the storage pod (100) and reaches between 5% to 80%, particularly 15% to 70%, preferably 20% to 50%, of the height (104) of at least one side.

7. The storage pod (100) according to claim 5 or 6, wherein the storage pod (100) has a height (104) in the range of 10 mm to 30 mm, and / or the gap (160, 161) has a height in the range of 0.5 mm to 24 mm, particularly 1.5 mm to 21 mm, preferably 2 mm to 15 mm.

8. The storage pod (100) according to claim 1, wherein a winding path (112, 124) is provided between the at least two components (110, 120) in at least a portion of at least one side surface of the storage pod (100), and no gap (160, 161) is formed in the portion thereof.

9. The stocker pod (100) according to claim 1, wherein a filter and / or obstruction (165) configured to affect the flow of purge gas is provided in the gap (160, 161).

10. The stocker pod according to claim 1, wherein the semiconductor manufacturing article (150) is one of the group consisting of a wafer, a part of a wafer, a reticle, and in particular an EUV reticle.

11. The stocker pod (100) according to claim 1, comprising at least 75%, 80%, 90%, 95%, or 99%, and up to 100% of the mass and / or volume of a metallic material.

12. The stocker pod (100) according to claim 1, further comprising a retainer configured to secure an article to the stocker pod (100) when the fasteners (130, 134) are in at least the closed position.

13. A stocker pod (100) for storing semiconductor manufacturing articles (150), wherein the stocker pod (100) comprises at least two components (110, 120) having at least one fastener (130, 134), the at least one fastener (130, 134) being integrally formed with at least one of the at least two components (110, 120) of the stocker pod (100), and the fastener (130, 134) is the stocker A storage pod (100) configured to fix two or more of the aforementioned components (110, 120) of the pod (100) to each other, wherein at least one of the fasteners (130, 134) is configured to be lockable in the open position to overcome a bias toward the closed position, and when the at least two components (110, 120) are fixed to each other, a gap (160, 161) is formed between them on at least one side of the storage pod (100).

14. A method for storing semiconductor manufacturing articles (150), comprising storing the semiconductor manufacturing articles (150) in a stocker pod (100) according to any one of claims 1 to 13, and storing the stocker pod (100) in a storage position of a semiconductor manufacturing stocker, particularly a reticle stocker.

15. The method according to claim 14, further comprising housing an EUV double pod containing an EUV inner pod and an EUV outer pod, containing the semiconductor manufactured article (150), opening the EUV outer pod and the EUV inner pod, recovering the semiconductor manufactured article (150) from the EUV inner pod, and arranging the stocker pod (100) around the semiconductor manufactured article (150) recovered from the EUV inner pod.

16. The method according to claim 14 or 15, comprising moving the fasteners (130, 134) to the open position, opening the stocker pod (100), placing the semiconductor manufacturing article (150) in the stocker pod (100), closing the stocker pod (100), and releasing the fasteners (130, 134).

17. A stocker for storing semiconductor manufacturing articles (150), in particular EUV reticles, comprising the method described in any one of claims 14 to 16, and configured to hold a number of stocker pods (100) in storage positions of the stocker.

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