Storage compartment

Abstract

A storage compartment for storing EUV pod components, comprising a plurality of subcompartments (120a-120e), each subcompartment adapted to store one EUV pod component, wherein the plurality of subcompartments are arranged in a vertically stacked order, each subcompartment of the plurality of subcompartments defines a vertically extending front and a vertically extending back, and a plurality of shutters (128a-128e) are provided such that the front of each of the plurality of subcompartments (120a-120e) has a corresponding shutter from the plurality of shutters (128a-128e), each corresponding shutter being vertically movable to provide an open and closed state of the corresponding subcompartment (120a-120e), and each shutter of the plurality of shutters (128a-128e) is movable independently of any other shutter of the plurality of shutters.

Description

Technical Field

[0001] The present invention relates to a stocker compartment for storing EUV pod components as described in the preamble of claim 1. The present invention also relates to a stocker having a plurality of such stocker compartments.

Background Art

[0002] The photolithography process is widely used as one of the important processes in the manufacture of integrated circuits (ICs) and other semiconductor-related devices and / or structures. However, as the dimensions of the fine structures (features) produced by such processes become smaller, the importance of photolithography in the manufacture of small ICs and other devices and / or structures is increasing.

[0003] In photolithography, a geometric pattern is transferred from a photomask (usually called a reticle) onto a substrate, such as a semiconductor wafer, by using light, a photosensitive layer, and subsequent etching processes. Depending on the desired fine structure size on the substrate, it is necessary to adapt the fine structure size of the reticle and the wavelength of the light used for pattern transfer in consideration of the Rayleigh criterion.

[0004] In order to reduce the achievable minimum fine structure size, the use of extreme ultraviolet (EUV) radiation has been proposed. EUV radiation is electromagnetic radiation having a wavelength within the range of 5 to 20 nm, for example, within the range of 5 to 10 nm.

[0005] When the reticle is contaminated, the image formation performance of the photolithography process deteriorates, and in severe cases, it may be necessary to replace the reticle. Since reticles are generally expensive, it is advantageous if the frequency of reticle replacement can be reduced. Furthermore, reticle replacement is a time-consuming process during which the photolithography process may have to be interrupted, resulting in reduced efficiency, which is undesirable.

[0006] For EUV applications, particle contamination with a particle size of less than 10 nm, and chemical contamination due to adsorption of volatile organic compounds, for example, can be problematic.

[0007] Therefore, reticles used for such EUV applications are typically stored in storage containers, hereafter simply referred to as stockers, and retrieved when needed in connection with the lithography exposure equipment. Typically, during transport and storage in the stocker, 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 dual pods are described in more detail, for example, in U.S. Patent Application Publication No. 2019 / 0214287.

[0009] Because the acceptable level of particulate contamination is extremely low, friction between the reticle and the container (which causes wear and ultimately leads to particle generation) and friction between the container components themselves must be avoided. Therefore, a typical EIP is designed to house only one reticle, so that the possibility of the reticle moving within it is very limited. The EIP also includes an additional reticle retainer configured and fitted to hold the reticle in place within the EIP. To prevent contamination, the EIP is designed to allow the application of a protective gas or vacuum to the reticle. For this purpose, a typical orifice with filter material is usually provided so that the protective gas is introduced from the EOP around the reticle housed in each EIP.

[0010] The EOP (Electronic Operating Unit) is equipped with an actuator adapted to bias the reticle fixing means of the EIP (Electronic Inspection Panel) into a holding position, thereby fixing the reticle within the EIP when the EOP is attached to the EIP. The EOP also serves to fix two typical parts of the EIP together to prevent wear due to friction.

[0011] It should be understood that EIP components are movable relative to each other unless they are fixed from the outside. To avoid wear due to friction caused by such movement, EOPs conventionally provide such a fixing function to the EIP, as well as protection from the ambient atmosphere, such protection is necessary, for example, during transport between storage locations and processing tools that require a reticle for operation.

[0012] Because EOP is quite bulky, storage containers for EUV reticles require high space requirements, i.e., a large "footprint." Furthermore, since EOP is made of polymer materials, it is prone to wear and easily releases volatile organic compounds. [Overview of the Initiative]

[0013] The present invention addresses these problems by providing a storage compartment and a storage container having the features of each independent claim. Advantageous embodiments and additional features are provided in the dependent claims and are further described below.

[0014] The present invention provides a storage compartment for an EUV pod component, particularly an EIP configured and adapted to house a reticle or at least a reticle, comprising a plurality of subcompartments, each of which is adapted to house one EUV pod component. The plurality of subcompartments are arranged in a vertically stacked order, and each subcompartment of the plurality of subcompartments defines a vertically extending front and a vertically extending rear. A plurality of shutters are provided such that the front of each of the plurality of subcompartments has a corresponding shutter from the plurality of shutters, each corresponding shutter is vertically movable to provide an open and closed state of the corresponding subcompartment, and each shutter of the plurality of shutters is movable independently of any other shutter from the plurality of shutters. The ability of one shutter to move independently of any other shutter among multiple shutters means, in particular, that when one shutter is moved vertically from a closed position to an open position, causing the corresponding subcompartment to change from a closed state to an open state, all other shutters within the compartment remain in their respective closed positions (i.e., maintaining the closed state of the corresponding subcompartment). This eliminates the need to move multiple shutters simultaneously to open only a single subcompartment, as in conventional solutions. This minimizes mechanical movement within the stocker compartment and reduces particle generation due to abrasion. This also minimizes the vertical space required for the operation of the stocker compartment.

[0015] As described above, storing the EIP in a storage subcompartment provides additional safety measures in relation to the possibility of earthquakes, because the EIP containing the reticle is normally stored safely in a closed subcompartment with each shutter fixed in the closed position.

[0016] Advantageously, each shutter of a set of shutters is movable vertically upward or downward such that, when the subcompartment is open, some or all of the corresponding shutters are positioned horizontally in front of or behind the shutters corresponding to vertically adjacent subcompartments. For example, by making the uppermost shutter movable vertically downward and the lowermost shutter movable vertically upward, the vertical space requirements necessary to operate the stocker compartment can be further minimized. This is because the uppermost shutter does not extend beyond the height or upper edge of the stocker compartment in both the closed and open states, and similarly, the lowermost shutter does not extend below the lower edge of the stocker compartment in either the open or closed state.

[0017] Conveniently, each of the multiple subcompartments has a rear wall, and each corresponding shutter and rear wall of the multiple subcompartments has multiple openings adapted to allow the flow of purge fluid or gas through each of the multiple subcompartments. This allows for a highly effective purge gas flow through each subcompartment, minimizing contamination of the EIP stored in the subcompartments by suspended particles.

[0018] Advantageously, each shutter in the multiple shutters has multiple openings arranged in a predetermined pattern, and when a corresponding shutter in a compartment is moved vertically so that it is positioned horizontally in front of or behind a shutter in a vertically adjacent subcompartment, the pattern of the moved shutter and the pattern of the shutters in the vertically adjacent subcompartment are aligned with each other. This allows the laminar flow of the purge gas through the subcompartment to be maintained even when two shutters are temporarily positioned in front of the subcompartment.

[0019] According to a preferred embodiment of the present invention, the shutter is fixed by a magnetic fixing mechanism in positions that define the closed and open states of the corresponding subcompartment. Such a magnetic fixing mechanism can be implemented, for example, in a contact manner in which a magnet provided on the movable shutter contacts a non-movable stopper element, or in a non-contact manner in which, for example, a magnet provided on the movable shutter is positioned near such a stopper element, and a sufficient attractive force is generated between the magnet and the stopper element to fix the shutter in this position. This further minimizes the effects of wear associated with the movement of the shutter.

[0020] Advantageously, a guide rail mechanism is provided to guide each shutter between a position defining the open state and a position defining the closed state of its corresponding sub-compartment.

[0021] According to a preferred embodiment, the magnetic fixing mechanism and / or guide rail mechanism are located in a shielded environment separated from each of the subcompartments. By locating the magnetic fixing mechanism and / or guide rail mechanism in a shielded environment, i.e., an environment shielded from the subcompartments housing the EIP, contamination of the subcompartments due to wear caused by the magnetic fixing mechanism or guide rail mechanism can be avoided, or at least minimized.

[0022] Conveniently, the shielding environment for the guide rail mechanism includes an exhaust mechanism for discharging particles generated during the operation of the guide rail mechanism from the shielding environment.

[0023] The stocker according to the present invention comprises at least one stocker compartment as described above, and a robotic mechanism configured and adapted to move each of a plurality of shutters so that the shutters moved by the robotic mechanism provide an open or closed state for the corresponding subcompartment. A stocker having a plurality of compartments may have a single robotic mechanism corresponding to all compartments, or it may have a plurality of robotic mechanisms, for example, two or three robotic mechanisms.

[0024] This invention makes it possible to reduce the space required to store the reticle while ensuring at least the same level of contamination and damage prevention as that provided by conventional systems. Compared to storing the reticle in a double pod, chemical contamination during storage due to outgassing of the EOP is prevented, and protection against mechanical damage is improved. For example, the EOP can be easily damaged during an earthquake. As will be understood from the following explanation, storing the EIP with the reticle in a subcompartment as described above is substantially safer even under severe conditions such as an earthquake.

[0025] When developing such an improved storage concept, aspects that need to be considered include that it is highly undesirable to change the way the reticle is supplied to the photolithography processing apparatus. This is usually the most complex and costly part in semiconductor manufacturing equipment.

[0026] Therefore, since the photolithography processing apparatus is usually adapted to receive a dual pod, advantageously, the improved compartment or stocker is provided with means for providing a conventional dual pod to the photolithography processing apparatus.

[0027] It should be noted that all method steps described below in this specification can advantageously be implemented by an automated method, for example by a robotic component.

Brief Description of the Drawings

[0028] Next, the advantages and further aspects of the present invention will be further described with reference to the accompanying drawings.

[0029] [Figure 1] FIG. 1 is a perspective view of a first preferred embodiment of a stocker according to the present invention. [Figure 2] FIG. 2 is a partially cutaway view of the stocker shown in FIG. 1. [Figure 3] FIG. 3 is a view corresponding to FIG. 2 with one sub-compartment in an open state. [Figure 4a] FIG. 4a is a side cross-sectional view and a front view of a stocker showing a magnetic fixing mechanism for fixing a shutter in its closed and open positions. [Figure 4b] FIG. 4b is a side cross-sectional view and a front view of a stocker showing a magnetic fixing mechanism for fixing a shutter in its closed and open positions. [Figure 4c] FIG. 4c is a side cross-sectional view and a front view of a stocker showing a magnetic fixing mechanism for fixing a shutter in its closed and open positions. [Figure 4d]Figure 4d shows a side cross-sectional view and a front view of a stocker illustrating a magnetic fixing mechanism for securing the shutter in its closed and open positions. [Modes for carrying out the invention]

[0030] In Figures 1 to 3, the reticle stocker is generally shown as 100. In the illustrated embodiment, the stocker 100 comprises one stocker compartment 110, which contains five (or more) subcompartments (numbered 120a to 120e for convenience, from the bottom subcompartment to the top subcompartment, as can be seen in Figures 2 and 3) arranged to stack vertically on top of each other. The stocker 100 further comprises a robotic mechanism 130. Each subcompartment 120a to 120e is adapted to house one of the inner pods (so-called EIPs) of an EUV double pod.

[0031] In many applications, the stocker typically comprises multiple stocker compartments 110 arranged vertically stacked on top of each other, and / or multiple stocker compartments 110 arranged horizontally adjacent to each other, which can advantageously be operated by a single robotic mechanism 130. For simplicity of illustration, the figure shows a stocker with only one compartment.

[0032] Each subcompartment 120a to 120e is defined by a floor 122, a ceiling 124, a rear wall 126, shutters 128a to 128e, and side walls 125 and 127. The side walls 125 and 127 and the rear wall 126 can be provided as a unitary wall extending across all subcompartments 120a to 120e. For example, as can be seen in Figure 2, the ceiling 124 of subcompartment 120d corresponds to the floor 129 of subcompartment 120e which is vertically adjacent to subcompartment 120d.

[0033] Each subcompartment 120a–120e is adapted to securely house and hold one EIP containing a reticle, or at least one EIP configured and adapted to house one reticle. To ensure that the environment within the EIP remains uncontaminated, each subcompartment 120a–120e is provided with clamping devices (not shown) configured and adapted to secure the EIP components and the reticle housed within the EIP to each other. Such clamping devices are either permanently installed within each subcompartment 120a–120e or clamped around the EIP before being introduced into the subcompartment. If the clamping devices are permanently installed within the subcompartment, they conveniently serve to secure the EIP to the subcompartment. If the clamping devices are inserted into the subcompartment together with the EIP (with or without a reticle), conveniently a separate mechanism is provided for securing the EIP within the subcompartment.

[0034] In Figures 1 and 2, each subcompartment 120a to 120e is shown in a closed state. That is, the front of each subcompartment 120a to 120e is restricted, or closed, by the respective shutters 128a to 128e associated with each subcompartment.

[0035] Each shutter 128a to 128e is individually displaceable along the vertical direction by the robot mechanism 130, either vertically upward or vertically downward (indicated by double-headed arrows 99 in Figure 1), thereby providing open and closed states for each subcompartment.

[0036] Referring to Figure 3, it is shown that subcompartment 120c is in an open state when its shutter 128c is moved vertically upward and positioned horizontally behind the shutter 128d of the adjacent subcompartment 120d above it.

[0037] To achieve this movement, the arm 132 of the robot mechanism 130 is equipped with a gripper 134 adapted to engage with a handling ridge 150 provided on each shutter 128a to 128e. Therefore, when the arm 132 of the robot mechanism is moved vertically upward, one of the shutters 128a to 128e that is gripped by the gripper 134 or otherwise engaged will move upward.

[0038] By using such a robotic mechanism, the need for a complex system including active drive devices and corresponding sensors for each shutter is eliminated. Therefore, by providing a robotic mechanism, the effects of wear and, consequently, contamination in the vicinity of the stocker compartment 110 can be minimized. Furthermore, the robotic mechanism is configured and adapted to handle EUV pod components, particularly EIPs stored in subcompartments. For example, after opening the subcompartment by moving its shutter vertically, the robotic mechanism can place the EIPs into the subcompartment or remove them from the subcompartment.

[0039] To minimize the height requirements of the storage compartment, preferably, the shutter 128e of the uppermost subcompartment 120e is movable vertically downward, while the shutter 128 of the lowermost subcompartment 120a is movable vertically upward. The shutters 128b to 128d of the three intermediate subcompartments 120b to 120d are movable either upward or downward. In the illustrated embodiment, shutters 128a and 128c are movable upward, and shutters 128b, 128d and 128e are movable downward. This ensures that the height requirements of the compartment 110 during use do not exceed the physical height of the compartment 110 itself.

[0040] To enable the shutters 128a to 128e to be moved so that they are positioned horizontally behind each other, shutters 128b and 128d are positioned with a small horizontal offset relative to shutters 128a, 128c, and 128e, as can be seen in Figures 1 to 3. In this regard, it should be noted that the position of the handling ridge 150 on each shutter 128a to 128e depends on whether it is positioned slightly forward or slightly backward in the horizontal direction. For example, as can be seen in Figure 1, shutter 128d is positioned slightly forward in the horizontal direction, and its handling ridge 150 is positioned centrally relative to the vertical extension of the shutter. This handling ridge can be easily grasped and moved by the robot mechanism 130. In contrast, for example, shutter 128e is positioned offset to the rear in the horizontal direction, and a handling ridge 150 is provided at or near its upper end as a handling ridge for shutter 128e. This allows the robot mechanism 130 to grasp the handling ridge 150 of shutter 128e and move it downward without contacting shutter 128d, which is located directly below shutter 128e.

[0041] During movement by the robotic mechanism 130, the shutters 128a to 128e are guided by guide rail mechanisms 180 provided on both sides of the shutters. The guide rail mechanisms are located within a shielded environment 181 provided by the respective housings 182 provided on both sides of the shutter 128. In Figure 1, to visually illustrate the guide rail mechanism 180, the housing 182 on the right side of the shutter 128 is shown with one of the housing walls removed.

[0042] The shutters 128a to 128e are held in their respective closed and open positions non-contact by a magnetic fixing mechanism. This point will be further explained below with reference to Figures 4a to 4d.

[0043] To further minimize the risk of contamination caused by wear as the shutter moves along the guide rail mechanism, the housing 182 is provided with an exhaust mechanism, for example, including a suction means. Such an exhaust mechanism is schematically shown in Figure 1 and is numbered 190. This exhaust mechanism can be configured to create a vacuum within the shielded environment 181 by exhausting gases and particles present within the shielded environment 181.

[0044] Each shutter 128a to 128e is provided with an opening 160 through which purge gas supplied to flow through each subcompartment 120a to 120e can be discharged. Typically, such purge gas flows into the subcompartments 120a to 120e through an opening (not shown) in the rear wall 125, flows around the EIP provided within the subcompartment, and then flows laminarly towards the opening 160 in the shutters 128a to 128e. This purge gas flow requires substantially less purge gas compared to conventional solutions. To further minimize the amount of purge gas required, the opening in the rear wall 125 and the openings in the shutters 128a to 128e can be made to correspond to each other.

[0045] For example, by providing the openings in the rear wall 125 in the same or a similar pattern as the openings in the shutters 128a to 128e, the laminarity of the flow can be increased, thereby reducing the consumption of purge gas.

[0046] Furthermore, by arranging the openings of each shutter in a corresponding pattern, even when a corresponding shutter is moved to a position in front of or behind the shutter of an adjacent subcompartment to open the subcompartment, the positions of the openings of both shutters can be aligned. As a result, laminar flow is maintained when flowing out of the subcompartment, even if the subcompartment is temporarily restricted by the double shutters in front of it. To maximize this effect, the two shutters, positioned one behind the other horizontally, are moved only by the minimum distance selected so as not to cause wear when one shutter moves in front of or behind the other.

[0047] Advantageously, a measuring device is provided for measuring the concentration of airborne particles in the shielded environment within the housing 182. For example, by monitoring the concentration of particles generated during the mechanical movement of the guide rail mechanism 180, wear and damage to the mechanism can be monitored, and components can be replaced when necessary.

[0048] Next, with reference to Figures 4a to 4d, preferred embodiments of the magnetic fixing mechanism for holding the shutters in their respective closed and open positions will be described. Figures 4a and 4b are side and front views of the reticle stocker compartment 110, respectively, where all shutters 128a to 128e are in the closed position. Figures 4c and 4d are side and front views of the reticle stocker compartment 110, respectively, where shutter 128b is in its open position, while all other shutters 128a and 128c to 128e remain in their closed positions. In order for shutter 128b to reach its open position, shutter 128b is moved downward (by the robotic mechanism 130 described above) so that it is positioned in front of the lowest shutter 128a. Therefore, from the viewpoint of Figure 4d, shutter 128b is visible, but shutter 128a is not visible because it is located behind shutter 128b.

[0049] Each shutter 128a to 128e is equipped with a magnet 410, which interacts with stopper elements 420 and 430 that define the open and closed positions of the shutter. The stopper elements 420 and 430 are also provided as magnets or are made of magnetic material, and the magnet 410 receives an attractive force when it comes into contact with these stopper elements. Therefore, as can be seen in Figure 4a, the closed position of shutter 128b is defined when the magnet 410 comes into contact with stopper element 420, as shown in Figure 4b, and the open position of shutter 128b is defined when the magnet 410 comes into contact with stopper element 430, as shown in Figure 4d. In Figures 4a to 4d, for the sake of simplicity, only the magnet 410 of shutter 128b and the stopper elements 420 and 430 that interact with it are shown.

[0050] The magnet 410 and the stopper elements 420 and 430 are provided within the shielding environment 181, as well as in the vicinity of the guide rail mechanism 180. Therefore, wear action within the shielding environment 181, where contaminating particles may be generated, can be avoided, especially when the shutter reaches the open or closed position.

[0051] The magnetic fixing mechanism may be provided in a non-contact manner. For example, the magnet and stopper element may be provided in such a way that sufficient attractive force is generated by moving the (movable) magnet provided on the shutter to the vicinity of the non-movable stopper element in a non-contact manner, thereby fixing the magnet, and consequently the shutter, in the defined position. In this case, an external force, such as the force generated when the robot mechanism 130 grips the handling ridge 150, is required to remove the magnet from that position (i.e., within the range of magnetic interaction with the stopper element).

[0052] The magnetic fixing mechanism can also be implemented as an electromagnetic system. In this case, the corresponding current can be supplied via coil members provided in the shutter and guide rail mechanism. This solution also provides a reliable means for monitoring the position of any one of the shutters 128a to 128e.

[0053] In conclusion, providing a reticle stocker compartment with a sub-compartment equipped with a shutter enhances seismic safety. This is because, when the shutter is closed, even if the mechanism that secures the EIP within the sub-compartment (for example, the clamping device mentioned above) malfunctions, it effectively prevents the EIP containing the reticle from falling out of the sub-compartment.

Claims

1. A storage compartment for storing EUV pod components, The system comprises a plurality of subcompartments (120a to 120e), each subcompartment adapted to store one EUV pod component, the plurality of subcompartments arranged in a vertically stacked order, and each subcompartment of the plurality of subcompartments defines a vertically extending front and a vertically extending rear. Multiple shutters (128a to 128e) are provided such that the front surface of each of the multiple subcompartments (120a to 120e) is provided with a corresponding shutter from the multiple shutters (128a to 128e), and each corresponding shutter is vertically movable to provide the open and closed states of the corresponding subcompartments (120a to 120e). Each of the plurality of shutters (128a to 128e) is characterized in that it can move independently of any other shutter in the plurality of shutters. Storage compartment.

2. The storage compartment according to claim 1, wherein each of the plurality of shutters (128a to 128e) is movable vertically upward or vertically downward so that when the subcompartment is open, part or all of the corresponding shutter is positioned horizontally in front of or behind the shutter corresponding to a vertically adjacent subcompartment.

3. The stocker compartment according to claim 1 or 2, wherein the rear of each of the plurality of subcompartments is provided with a rear wall, and each corresponding shutter (128a to 128e) and each rear wall of the plurality of subcompartments (120a to 120e) is provided with a plurality of openings (160) adapted to allow the flow of purge fluid or gas through each of the plurality of subcompartments.

4. The storage compartment according to claim 3, wherein each shutter of the plurality of subcompartments (120a to 120e) is provided with a plurality of openings (160) arranged in a predetermined pattern, and when the shutter of a compartment is moved vertically so that it is positioned in front of or behind the shutter of a vertically adjacent subcompartment in the horizontal direction, the pattern of the moved shutter and the pattern of the shutter of the vertically adjacent subcompartment are aligned with respect to each other.

5. A storage compartment according to any one of claims 1 to 4, wherein at least one of the plurality of shutters (128a to 128e) is fixed by magnetic fixing mechanisms (410, 420, 430) to positions that define the closed and open states of the corresponding subcompartment.

6. A storage compartment according to any one of claims 1 to 5, wherein a guide rail mechanism (180) is provided for guiding the plurality of shutters (128a to 128e) between a position defining the open state and a position defining the closed state of the corresponding subcompartment for each shutter.

7. The storage compartment according to claim 5 or 6, wherein the magnetic fixing mechanism (410, 420, 430) and / or the guide rail mechanism (180) are provided in a shielded environment (181) separated from each of the plurality of subcompartments (120a to 120e).

8. The storage compartment according to claim 7, wherein the shielding environment (181) for the guide rail mechanism (180) comprises an exhaust mechanism (190) for discharging particles generated during the operation of the guide rail mechanism (180) from the shielding environment (181).

9. A storage compartment (110) according to any one of claims 1 to 8, A robotic mechanism (130) configured and adapted to move each of the plurality of shutters (128a to 128e) to provide an open or closed state of the corresponding subcompartment (120a to 120e) as the shutter moved by the robotic mechanism (130), A storage unit equipped with this feature.

10. The stocker according to claim 9, wherein the robotic mechanism is further configured and adapted to handle EUV pod components, in particular EIPs.

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