Apparatus and method for cleaning cup-shaped hollow bodies, in particular transport containers for semiconductor wafers or EUV lithography masks

Abstract

The present invention relates to an apparatus 92 for cleaning a cup-shaped hollow body 94, the apparatus 92 comprising a contact wall 20 on which the hollow body 94 can be placed, at least one through-opening 24 formed by the contact wall 20, a cleaning device 40 capable of ejecting a cleaning fluid to clean a cover contact surface 96 when the hollow body 94 is placed on the contact wall 20, the cleaning device 40 comprising a cleaning head 42 that protrudes above the through-opening 24 when the hollow body 94 is placed on the contact wall 20, and a plurality of cleaning nozzles 100 capable of spraying the cleaning fluid onto the cover contact surface 96. The present invention also relates to a method for cleaning a cup-shaped hollow body 94 using an apparatus 92 of this type.

Description

[Technical Field]

[0001] The present invention relates to a device for drying pot-shaped hollow bodies, in particular transport containers for semiconductor wafers or EUV lithography masks. [Background technology]

[0002] The production of highly integrated electronic circuits and other sensitive semiconductor components today takes place in factories where so-called semiconductor wafers go through numerous processing steps. Most of these steps are carried out with great effort in clean rooms that are kept free of contaminants, especially particles. The reason for such complex processing is that particles that come into contact with the semiconductor material of the semiconductor wafers can affect, among other things, the material properties of the semiconductor wafers, resulting in entire production batches becoming defective, unusable, and having to be discarded.

[0003] As the integration density of semiconductor circuits increases, maintaining cleanliness becomes increasingly important. Furthermore, as the size of clean rooms increases, the effort required to maintain cleanliness increases exponentially. Therefore, semiconductor wafers are not transported "unprotected" from one processing station to the next. Instead, special transport containers (known as FOUPs (front opening unified pods)) are used. A FOUP is a box-shaped transport container into which multiple semiconductor wafers are inserted. A FOUP is usually closed with a removable cover. Without the cover, a FOUP has a basic pot-like shape with a rectangular base. The inserted semiconductor wafers can be transported from one clean room to another clean room protected from the outside while the FOUP is closed with the FOUP lid. When the FOUP reaches the processing station, it is opened, and the semiconductor wafers are removed and processed accordingly. After processing, the semiconductor wafers are transferred back into the FOUP and then transported to the next processing station.

[0004] Because of the significant production downtime caused by semiconductor wafer contamination, FOUPs must be cleaned from time to time. FOUPs are particularly susceptible to contamination from wear debris from semiconductor wafers during loading and unloading.

[0005] Therefore, the same applies to the transport containers for EUV lithography masks ("extreme ultraviolet radiation"). EUV lithography masks are used to manufacture very small integrated circuits. EUV lithography masks also need to be transported in the same way as semiconductors, and a similar situation arises. When we talk about FOUPs below, the statements in this regard apply equally to the transport containers for EUV lithography masks.

[0006] Devices for cleaning FOUPs are known, for example, from International Publication Nos. WO 2006 / 136224, WO 2005 / 001888, and German Patent Application Publication No. 102020129469. With such devices, the FOUP can be cleaned on both its inner and outer surfaces. As mentioned above, the FOUP is closed with a cover, which is removed only when semiconductor wafers are loaded into or removed from the FOUP. The outer surface of a FOUP is usually much more heavily contaminated than its inner surface. Here, the cover support surface plays a specific role. For example, in the FOUP presented in German Patent Application Publication No. 102020129469, the cover support surface is located between the inner and outer surfaces. However, in more modern FOUPs, the cover support surface is formed by a step on the inner surface, so that when the cover is placed on the cover support surface, it is positioned by the inner surface. Contaminants from the cover collect on the cover support surface due to contact with the cover. As a result, the cover support surface is more contaminated than the remaining inner surface. However, contaminants located on the inner surface can be deposited directly onto the semiconductor wafer, potentially causing the effects described above. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2006 / 136224 [Patent Document 2] International Publication No. 2005 / 001888 [Patent Document 3] German Patent Application Publication No. 102020129469 Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of embodiments of the present invention to provide a way to remedy the above drawbacks using simple and inexpensive means, in particular to provide a device for cleaning pot-like hollow bodies, which makes it possible to reduce the number of defective and unusable production batches of semiconductor wafers. Furthermore, a fundamental object of embodiments of the present invention is to provide a method by which such a device can be operated. [Means for solving the problem]

[0009] This object is achieved by the features specified in claims 1 and 11. Advantageous embodiments are the subject of the dependent claims.

[0010] An embodiment of the invention relates to a device for cleaning a pot-shaped hollow body, in particular a transport container for semiconductor wafers or EUV lithography masks, the hollow body comprising: - a bottom wall and one or more side walls forming the interior surface of the hollow body; an opening disposed opposite the bottom wall and surrounded by a side wall; - a cover support surface formed by the side walls and onto which a cover can be placed to close the hollow body; The device comprises: - a supporting wall on which the hollow body can be placed; - at least one passage opening formed by the support wall; a cleaning device that can discharge a cleaning fluid to clean the cover support surface when the hollow body is placed on the support wall; The cleaning device comprises: the hollow body, when placed on the support wall, projects above the passage opening, and a plurality of cleaning nozzles capable of spraying cleaning fluid onto the cover support surface; A cleaning head is provided.

[0011] The support surface of the hollow body rests on the support wall and is optionally locked to hold the hollow body in place relative to the support wall. It should be noted that the support wall does not correspond to the cover support surface in this case. Rather, in the following it is assumed that the cover support surface is part of the inner surface of the hollow body and is formed by the side wall of the hollow body.

[0012] Due to the fact that the cleaning head is equipped with cleaning nozzles specially designed for cleaning the cover support surface, the cover support surface can be cleaned very thoroughly, so that contaminants that may deposit on the semiconductor wafer are removed over a wide area, which results in a significant reduction in the number of defective and unusable production batches of semiconductor wafers compared to prior art devices.

[0013] According to a further embodiment, the cleaning head can comprise a number of drying nozzles, which can spray a drying gas onto the cover support surface. In this embodiment, the proposed device can be used not only for cleaning the hollow body, but also for subsequent drying. To finish the cleaning process, the supply of cleaning fluid is stopped and instead a drying gas, e.g., air or nitrogen, which dries the cover support surface, is delivered towards the drying nozzles. Residues of cleaning fluid still remaining on the cover support surface are removed by the drying gas.

[0014] In further developed embodiments, the cleaning head can be moved in a rotational or translational manner. The mobility of the cleaning head allows it to adapt to special geometric configurations of the cover support surface. In particular, it is possible to spray the first cleaning fluid at least approximately perpendicularly to the cover support surface, so that the kinetic energy of the cleaning fluid can be used particularly effectively to clean the cover support surface.

[0015] In a further developed embodiment, the cleaning fluid and / or drying gas can be discharged at an angle, and the cleaning head includes a setting device that cooperates with the cleaning nozzle and / or the drying nozzle and allows the setting of the angle. The angle at which the first cleaning fluid is discharged also determines the angle at which the cleaning fluid strikes the cover support surface. An angle of 90° or approximately 90° is ideal. The fact that the angle can be set allows the geometry of the hollow body interior to be modeled so that the first cleaning fluid is sprayed at an angle of 90° or approximately 90° over most of the cover support surface and adjacent areas of the hollow body interior. The hollow body interior typically has intricate sections, and non-adjustable cleaning nozzles that spray zero or only limited amounts of cleaning fluid onto the hollow body interior, especially the cover support surface and adjacent areas, even with sufficient kinetic energy, can create shadows. This embodiment avoids such shadows, thereby improving the overall cleaning results.

[0016] In a further embodiment, the cleaning head can include a plurality of infrared diodes capable of heating the cover support surface, which can be heated by the infrared diodes to assist in the drying process performed using the drying gas, and any residue of cleaning fluid still remaining on the cover support surface can be removed as a result of the heating.

[0017] A further developed embodiment can be characterized in that the cleaning head has an outer shape that at least approximately follows the course of the hollow body interior, so that the distance between the hollow body interior and the cleaning head is constant or approximately constant. A distance of 1 mm to 50 mm, particularly 10 mm to 30 mm, has proven to be ideal for achieving good cleaning results. A short distance contributes to the generation of a strong, directed flow in the space between the hollow body interior and the cleaning head, resulting in particularly good cleaning and drying effects. This distance does not always have to be the same throughout the entire intermediate space; it can also vary, which is advantageous, for example, when the sidewalls form protrusions, recesses, and / or undercuts. Here, it may be preferable for the cleaning head to simply be approximately complementary to the course of the hollow body interior, so that the outer shape of the cleaning head does not follow the individual protrusions and / or recesses of the sidewalls. In this case, the cleaning head can be retracted into the interior space more easily and quickly, without compromising the cleaning and / or drying effect.

[0018] According to a further embodiment, the device can comprise at least one coupling unit for coupling sound waves into the cleaning fluid. In this regard, sound waves can be, in particular, ultrasonic or megasound waves. Ultrasound, by definition, has a frequency range of approximately 20 kHz to 500 kHz, while megasound waves have a frequency range of approximately 500 kHz to 3 MHz. It appears preferable here to couple sound waves into the cleaning fluid by completely wetting the inner surface of the hollow body with the cleaning fluid or by filling the space between the cleaning head and the inner surface of the hollow body. The cleaning fluid then acts as a carrier for the sound waves. Due to the fact that a certain amount of energy is thereby transferred into the cleaning fluid, particles adhering to the cover support surface can be particularly easily removed, thereby enhancing the cleaning effect. The energy input increases depending on the frequency of the coupled sound. The advantage of using megasound is that the energy can be brought to the cover support surface and cleaning can be performed in a very targeted manner, resulting in excellent cleaning results.

[0019] In a further embodiment, it may be advantageous for at least some of the coupling units to be integrated into or cooperate with at least some of the cleaning nozzles. The cleaning nozzles may in this case be designed as so-called "megasonic nozzles" which allow coupling of sound waves into the first cleaning fluid discharged from the first cleaning nozzles. In this case, it is not necessary to wet the entire inner surface of the hollow body with the first cleaning fluid, which allows the amount of first cleaning fluid required to be kept low.

[0020] In a further developed embodiment, the device can include a first discharge flow path having a first end, the first end of which is fluidly connected only to the passage opening, thereby allowing the cleaning fluid dispensed from the cleaning device to be discharged. In this embodiment, the cleaning fluid only comes into contact with the inner surface of the hollow body. Although the outer surface of the hollow body is usually more contaminated than the inner surface of the hollow body, the impact of contaminants on the inner surface of the hollow body is particularly large compared to contaminants on the outer surface of the hollow body in terms of the number of defective production batches of semiconductor wafers due to the small spatial distance between the contaminants on the inner surface of the hollow body and the semiconductor wafers. In this embodiment, the cleaning fluid can only come into contact with the inner surface of the hollow body, so it is not contaminated by contaminants on the outer surface of the hollow body. In this respect, the cleaning effect of the cleaning fluid is not reduced.

[0021] In a further embodiment, a particle measuring device for determining particles contained in the cleaning fluid can be arranged in the discharge flow path. As mentioned, the cleaning fluid only comes into contact with the inner surface of the hollow body and, consequently, also comes into contact with the cover support surface. Since the cleaning nozzle is configured to clean the cover support surface, it can be assumed that the particles recorded by the particle measuring device originate only from the cover support surface or from a wider area. The particle measuring device can, for example, count the number of particles. If the number is below a certain threshold, this can be interpreted as a criterion that the hollow body has been cleaned to a sufficient extent. The cleaning process can then be terminated. This can save time and cleaning fluid.

[0022] According to a further embodiment, the cleaning head can include a plurality of additional cleaning nozzles for cleaning the hollow body interior surface. The additional cleaning nozzles can be of the same design as the cleaning nozzles for cleaning the cover support surface, but are positioned on the cleaning head so that cleaning fluid ejected from the additional cleaning nozzles does not strike the cover support surface. The remaining hollow body interior surface can be cleaned by the additional cleaning nozzles, further reducing the number of defective and unusable production batches of semiconductor wafers.

[0023] In a further embodiment, the cleaning head can include a flexible sheath that can be changed from a contracted state to an expanded state and back again by the cleaning fluid and / or drying gas. Here, the cleaning nozzle, the drying nozzle, and / or the additional cleaning nozzle can be formed as simple holes or perforations in the flexible sheath. Alternatively, the sheath can be formed as a membrane. This ensures that the cleaning fluid and / or drying gas drawn into the sheath can exit the cleaning head and reach the cover support surface and / or the inner surface of the hollow body. The flexible sheath is designed in this case to create a certain flow resistance when the cleaning fluid and / or drying gas is drawn into the flexible sheath, which must first be overcome before the cleaning fluid and / or drying gas can exit the sheath again through the holes or perforations. This flow resistance causes accumulation of the cleaning fluid or drying gas in the sheath, resulting in the sheath changing from a contracted state to an expanded state. The dimensions of the sheath in the expanded state can vary within certain limits depending on the pressure at which the cleaning fluid and / or drying gas is drawn into the sheath. In this respect, the distance between the inner surface of the hollow body and the cleaning head can be set to suit hollow bodies of various shapes.

[0024] An embodiment of the invention relates to a method for cleaning pot-shaped hollow bodies, in particular transport containers for semiconductor wafers or EUV lithography masks, using a device according to one of the previous claims, the method comprising the following steps: - placing the hollow body on a support wall; - discharging cleaning fluid to clean the cover support surface by a plurality of cleaning nozzles disposed on a cleaning head of the cleaning device such that the cleaning fluid is sprayed onto the cover support surface; and - Discharging the cleaning fluid through a discharge channel.

[0025] The technical effects and advantages that can be achieved with the proposed method also correspond to those discussed for the current device. In summary, it should be pointed out that the cover bearing surface can be cleaned in a targeted manner. The cover bearing surface, as mentioned, has a significant impact on the number of effectively unusable production batches of semiconductor wafers. By targeted cleaning of the cover bearing surface, this number can be significantly reduced compared to processes known in the prior art.

[0026] In a further embodiment, a method can be provided that includes the following steps. - determining particles contained in the cleaning fluid using a particle measurement device disposed in the discharge flow path; and - Terminating the discharge of the cleaning fluid when the particle-related threshold is exceeded or falls below the threshold.

[0027] The particle measuring device can, for example, determine the number and / or diameter of the particles. In addition, a threshold value for the number and / or diameter of the particles can be defined, below or above which may be an indication that the hollow body has been sufficiently cleaned and the cleaning procedure can be terminated. On the one hand, it can be documented that a given hollow body has indeed been cleaned to a sufficient extent, and on the other hand, the cleaning procedure can be terminated when the hollow body is sufficiently clean.

[0028] A further developed embodiment may specify that the method comprises the following steps: - completely filling the space intermediate the cleaning head and the inner surface of the hollow body with cleaning fluid, and - coupling acoustic waves into the cleaning fluid using a coupling unit.

[0029] The sound waves can be coupled, for example in the form of ultrasound or megasound, thereby improving the cleaning results, as energy is thereby incorporated into the first cleaning fluid and acts to dislodge particles on the hollow body inner surface.

[0030] A further embodiment may specify that the method comprises the following steps: - cleaning the cover support surface using a cleaning nozzle; and - cleaning the inner surface of the hollow body at different times using different cleaning nozzles.

[0031] As mentioned, the particles contained in the cleaning fluid can be determined, for example, by counting them using a particle measuring device as they flow through the discharge channel. It can be assumed that the particles removed during cleaning of the cover support surface using cleaning nozzles originate, at least to a significant extent, from the cover support surface. The same applies analogously to cleaning of the hollow body interior. Among the different cleaning nozzles, some cleaning nozzles can be operated at different times from other different cleaning nozzles. This allows a report to be made of whether certain areas of the hollow body interior are more contaminated than other areas, especially the cover support surface. Faults in the semiconductor wafer production routine can be concluded from this report.

[0032] In the following, exemplary embodiments of the invention will be explained in more detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0033] [Figure 1] 1 shows a basic cross-sectional view of a device according to the prior art for cleaning pot-shaped hollow bodies, in particular transport containers for semiconductor wafers or EUV lithography masks. [Figure 2] FIG. 2 is an enlarged, not to scale, view of detail A defined in FIG. 1; [Figure 3]1 shows a basic cross-sectional view of an embodiment of a device according to the invention for cleaning pot-shaped hollow bodies, in particular transport containers for semiconductor wafers or EUV lithography masks. [Figure 4A] 1 shows a basic cross-sectional view of a second embodiment of a device according to the invention for cleaning pot-like hollow bodies, with the flexible sheath in the contracted state; FIG. [Figure 4B] 1 shows a basic cross-sectional view of a second embodiment of a device according to the invention for cleaning pot-like hollow bodies, with the flexible sheath in the expanded state; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0034] An exemplary embodiment of a prior art device 10 for cleaning pot-shaped hollow bodies 12, as described, for example, in DE 10 2020129469 A1, is shown in FIG. 1 with reference to a basic cross-section. The device 10 comprises a housing 14, which defines a housing opening 16 that can be closed by a cover 18 that can be removed from the housing 14. A support wall 20 is further arranged in the housing 14, such that a closed process space 22 is provided in the housing 14. The process space 22 is delimited by the support wall 20, the housing 14 itself, and the cover 18. The support wall 20 defines a passage opening 24, and a locking device 26 is arranged radially outside the passage opening 24. In the illustrated embodiment, two passage holes 28 are provided in the support wall 20, radially outside the locking device 26.

[0035] Once the cover 18 is removed, the hollow body 12, in particular a transport container 30 for semiconductor wafers, also called FOUP, or a transport container 30 for EUV lithium masks, can be introduced into the process space 22. The hollow body 12 has a bottom wall 32 and, in this case, four side walls 34, so that the pot-shaped hollow body 12 is substantially parallelepiped in shape. However, it is of course also possible for the pot-shaped hollow body 12 to have a different geometric shape, for example a cylindrical geometry. The bottom wall 32 and the four side walls 34 form an inner hollow body surface 33 and an outer hollow body surface 35.

[0036] The hollow body 12 has an opening 36 arranged opposite the bottom wall 32 and surrounded by a peripheral surface 38 formed by the side wall 34. In the embodiment shown, the hollow body 12 is designed flange-like in the region of the peripheral surface 38. The peripheral surface 38 of the hollow body 12 can rest on the support wall 20. The passage opening 24 in the support wall 20 and the opening 36 in the hollow body 12 are, in the embodiment shown, at least approximately of the same size and of the same geometric shape.

[0037] The locking device 26 is further configured so that the passage opening 24 is at least approximately flush with the portion of the hollow body inner surface 33 adjacent the passage opening 24 .

[0038] The area A marked in Figure 1 is not shown to scale in Figure 2 and does not correspond exactly. For illustrative reasons, the locking device 26 is not shown. It can be seen from Figure 2 that the support wall 20 comprises a support wall portion 37 which forms a contact surface 39 which comes into contact with a peripheral surface 38 of the transfer container 30. In this respect, the contact surface 39 of the support wall portion 37 is completely covered by the peripheral surface 38. A first channel 41 is arranged in the support wall portion 37 and opens onto the contact surface 39, through which a flushing fluid, for example air or nitrogen, can be guided towards the peripheral surface 38.

[0039] The device 10 is further equipped with a cleaning device 40 comprising a first cleaning head 42 which projects above the passage opening 24 and is thus arranged in the process space 22. When the hollow body 12 is connected to the support wall 20, the first cleaning head 42 is surrounded by the hollow body 12.

[0040] The housing 14 further comprises a wall portion 44 in which a cleaning opening 46 is arranged. The wall portion 44 is located on a side of the support wall 20 remote from the locking device 26. The cleaning opening 46 can be at least partially closed by a closure 48 that is fixed to the wall portion 44 so as to be rotatable about a first rotation axis D1 by a drive unit (not shown). The closure 48 can be moved between an open position in which the closure 48 opens the cleaning opening 46 and a closed position in which the closure 48 at least partially closes the cleaning opening 46. In FIG. 1 , the closure 48 is in the closed position.

[0041] The closure body 48 comprises a receiving unit 50 by means of which a cover 52, with which the hollow body 12 can be closed, can be releasably fixed to the closure body 48. The cover 52 forms an inner cover surface 54 and an outer cover surface 56. The inner cover surface 54 here is the side of the cover 52 that is directly adjacent to the hollow body inner surface 33 when the hollow body 12 is closed by the cover 52. In other words, the inner cover surface 54 faces in this case towards the bottom wall 32 of the hollow body 12.

[0042] The receiving unit 50 is designed in the illustrated embodiment to interact with the cover 52 only via the cover outer surface 56 .

[0043] The cleaning device 40 is further equipped with a separate first cleaning head 58 which is positioned adjacent to the closure body 48 when the closure body 48 is in the closed position.

[0044] The cleaning device 40 further comprises a second cleaning head 64 that is substantially U-shaped and at least partially disposed within the process space 22. However, unlike the first cleaning head 42, the second cleaning head 64 is disposed outside the hollow body 12 when the hollow body 12 is connected to the support wall 20 as shown in FIG. 1 . The second cleaning head 64 is rotatable about a second rotation axis, although a drive device used for this purpose is not shown. Furthermore, embodiments in which the second cleaning head 64 is not only rotationally movable but also translationally movable, or only translationally movable, are not shown. In the illustrated embodiment, the first cleaning head 42 is not movable, but it can also be designed to be rotationally and / or translationally movable.

[0045] The device 10 is further provided with a fluid directing unit 66 that can direct the first cleaning fluid to the first cleaning head 42 and the further first cleaning head 58 and can direct the second cleaning fluid to the second cleaning head 64. The fluid directing element 66 comprises a first supply channel 68 that can direct the first cleaning fluid to the first cleaning head 42.

[0046] A detailed illustration of the second supply channel for supplying the second cleaning fluid to the second cleaning head 64 has been omitted for illustrative purposes, but the design of the second supply channel should be readily apparent to one skilled in the art.

[0047] The fluid directing unit 66 further includes a first discharge flow path 70 through which the first cleaning fluid ejected from the first cleaning head 42 and the another first cleaning head 58 can be discharged again from the process space 22. The first discharge flow path 70 has a first end 72 that is in fluid communication with the passage opening 24. As can be seen in FIG. 1 , the first discharge flow path 70 expands in a funnel-like shape toward the first end 72 and is connected to the support wall 20 so that the first end 72 of the discharge flow path terminates flush with the passage opening 24.

[0048] The fluid conducting unit 66 further comprises a second discharge channel 76, which is designed substantially identically to the first discharge channel 70 but is in fluid communication with the two passage holes 28. In this regard, the first discharge channel 70 forms the radially inner wall of the second discharge channel 76, which allows the fluid conducting unit 66 to have a very compact design. It should be pointed out at this point that the fluid conducting unit 66 is only shown in principle in FIG. 1. The illustration of the fluid conducting unit 66 in FIG. 1 does not claim accuracy, since several channels are nested and arranged at different levels. At the same time, flushing fluid is conducted through the first channel 41 to the peripheral surface 38 and / or through the second channel 57 to the cover 52. While this may be the same flushing fluid, it is also possible to conduct a first flushing fluid through the first channel 41 and a second flushing fluid, different from the first flushing fluid, through the second channel 57. The flushing fluid, which is directed through the first flow path 41 to the peripheral surface 38, prevents the first and second cleaning fluids from passing through the peripheral surface. The flushing fluid therefore creates a fluid seal between the first and second cleaning fluids. As a result, it is ensured that the first and second cleaning fluids cannot mix. Contamination of the first cleaning fluid by the second cleaning fluid, and vice versa, is prevented. However, it should be pointed out that the flushing fluid has no or only a very limited cleaning effect on the peripheral surface 38 at this point.

[0049] The first cleaning fluid discharged from the first cleaning head 42 and sprayed onto the hollow body inner surface 33 is discharged through the first discharge channel 70. The same applies to the first cleaning fluid discharged from the other first cleaning head 58 and sprayed onto the cover inner surface 54. The first discharge channel 70 comprises a secondary channel 84 that opens into the first discharge channel 70 and discharges the first cleaning fluid used to clean the cover inner surface 54.

[0050] The flushing fluid directed to the cover 52 flows through the gap 60 and back into the secondary flow path 84. The housing seal 61 prevents the flushing fluid from flowing into the surroundings. The flushing fluid prevents the first cleaning fluid, discharged from the separate first cleaning head 58 and sprayed onto the cover inner surface 54, from reaching the cover seal 53 where particles in the first cleaning fluid may adhere.

[0051] The flushing fluid directed to the peripheral surface 38 and / or cover 52 may be pressurized sufficiently strongly.

[0052] Particles on the hollow body inner surface 33 and the cover inner surface 54 are removed by the first cleaning fluid. The second cleaning fluid, which is discharged from the second cleaning head 64 and sprayed onto the hollow body outer surface 35, is removed through the second discharge passage 76. Therefore, the first cleaning fluid and the second cleaning fluid are discharged separately from each other, and as a result, particles generated from the hollow body outer surface 35 cannot enter the first cleaning fluid, and therefore cannot enter onto either the hollow body inner surface 33 or the cover inner surface 54.

[0053] When the hollow body inner surface 33 and the cover inner surface 54 have been cleaned to the desired extent, the cleaning process can be terminated regardless of the extent to which the hollow body outer surface 35 has been prepared.

[0054] Here, the first drying gas and the second drying gas, e.g., air or nitrogen, can be guided to the first cleaning head 42, the other first cleaning head 58, and the second cleaning head 64 through a first supply passage 68 or a second supply passage (not shown) in much the same way as the first and second cleaning fluids. The first cleaning head 42 includes a first drying nozzle 86, the other first cleaning head 58 includes another first drying nozzle 88, and the second cleaning head includes a second drying nozzle 90, through which the first drying gas or the second drying gas can be discharged and sprayed onto the hollow-body inner surface 33, the cover inner surface 54, and the hollow-body outer surface 35. The first drying gas and the second drying gas expel the first cleaning fluid and the second cleaning fluid from the device 10. Furthermore, residues of the first and second cleaning fluids can be blown away.

[0055] After the drying process is completed, the cover 18 is opened and the closure body 48 is moved to the open position. The cleaned hollow body 12 is removed from the process space. The receiving unit 50 is stopped so that the cover 52 can be removed from the closure body 48 and fed to the hollow body 12 to close it. Another hollow body 12 to be cleaned can now be handled in the device 10 in the manner described.

[0056] In Figure 3, a first embodiment of the proposed device 921 for cleaning pot-like hollow bodies 94 is shown with reference to a basic cross-section. The basic design and the manner in which the proposed device 921 can be operated correspond substantially to what has been described here for the prior art device 10 shown in Figures 1 and 2. Therefore, in Figure 3 only the features that are important for the present invention are shown.

[0057] Comparing the hollow body 12 that can be cleaned using the device 10 shown in Figures 1 and 2 with the hollow body 94 that can be cleaned using the proposed device 921, it can be seen that the latter hollow body 94 has, in addition to the peripheral surface 38, a cover support surface 96 that is part of the hollow body inner surface 33 and is formed by a step in the side wall 34.

[0058] The cleaning device 40 comprises a cleaning head 98 equipped with a plurality of cleaning nozzles 100 capable of spraying a cleaning fluid onto the cover support surface 96. The cleaning head 98 is further equipped with drying nozzles 102 capable of spraying a drying gas onto the cover support surface 96. The cleaning nozzles 100 and the drying nozzles 102 can be of the same design and therefore do not differ in the view of Figure 3. The cleaning nozzles 100 can also be configured such that both a cleaning fluid and a drying gas can be sprayed onto the cover support surface 96 by the cleaning nozzles.

[0059] The cleaning nozzle 100 and / or the drying nozzle 102 cooperate with a setting device 104, which allows setting the spray angle α at which the cleaning fluid and / or the drying gas is discharged. For this purpose, the cleaning nozzle 100 and the drying nozzle 102 can be housed like a golf ball. Alternatively or additionally, in particular the cleaning nozzle 100 can be arranged on a tubular body 83 that can rotate about a third rotation axis D3 so that the spray angle α can be set. This makes it possible to achieve a perpendicular or nearly perpendicular application of the cleaning fluid and / or the drying gas to the cover support surface 96.

[0060] The device 921 further comprises at least one coupling unit 106 for coupling acoustic waves into the cleaning fluid. In the illustrated embodiment, several coupling units 106 are integrated into at least some of the cleaning nozzles 100, which are designed as so-called "megasonic nozzles". Megasonics can be coupled into the cleaning fluid discharged from the cleaning nozzles 100.

[0061] In addition, a further cleaning nozzle 108 is arranged in the cleaning head 98, which can spray a cleaning fluid onto the hollow body inner surface 33. In the embodiment shown, the further cleaning nozzle 108 is of the same design as the cleaning nozzle 100, which can clean the cover support surface 96. The cleaning nozzle and the further cleaning nozzle can also cooperate with a setting device 104 (not shown), which can, in particular, set the spray angle α. The cleaning head 98 can additionally be equipped with a further drying nozzle 110.

[0062] The cleaning nozzle 100 and the further cleaning nozzle 108 can be opened and closed independently of each other. It is therefore possible to clean different parts of the hollow body inner surface 33 first and other parts later. For example, parts that are historically less dirty can be cleaned first and parts that are historically more dirty can be cleaned later.

[0063] The cleaning head 98 can be moved in translation and / or rotation along or about a fourth axis of rotation D4 using a drive device (not shown). The cleaning head 98 further includes a plurality of infrared diodes 112 capable of heating the cover support surface 96. Additional infrared diodes 112 (not shown) can also be disposed in the cleaning head 98 to heat the remaining hollow body inner surface 33.

[0064] The cleaning head 98 has an outer shape that at least approximately follows the course of the hollow body inner surface 33 so that the distance A between the hollow body inner surface 33 and the cleaning head 98 is constant or approximately constant. The aim here is, on the one hand, to select the distance A as small as possible in order to generate a strong and clearly directed flow of cleaning fluid and / or drying gas in the space intermediate the hollow body inner surface 33 and the cleaning head 98, and, on the other hand, to minimize the volume of the intermediate space in order to keep the required amounts of cleaning fluid and drying gas as small as possible. In the illustrated embodiment, the distance A should be between 10 mm and 30 mm. The intermediate space is designed here in the form of an annular gap.

[0065] Additionally, a particle measuring device 114 is arranged in the first outlet channel 70 to determine particles contained in the cleaning fluid.

[0066] As mentioned, the device 921 according to the present invention can be operated in substantially the same manner as the prior art device described in FIGS. 1 and 2 . However, it should be noted that the cover support surface 96 can be cleaned at a time offset from the remaining hollow body inner surface 33. When cleaning the cover support surface 96, particles in the cleaning fluid flowing through the first discharge channel 70 can be assumed to originate from the cover support surface 96. The particles can be characterized for relevant parameters, such as the number of particles, using the particle measuring device 114. As soon as the number of particles per unit of time falls below a threshold, the supply of cleaning fluid to the cover support surface 96 can be interrupted. The remaining hollow body inner surface 33 can then be cleaned using another cleaning nozzle 108. The supply of cleaning fluid can also be stopped, for example, if the number of particles in the cleaning fluid, as it flows through the first discharge channel 70, falls below a certain threshold. The cleaning head 98 can rotate about and move along the fourth rotation axis D4 when cleaning both the cover support surface 95 and the hollow body inner surface 33. In addition, the injection angle α can be changed by a setting device 104 and the acoustic waves can be coupled into the cleaning fluid by a coupling unit 106 .

[0067] Subsequently, drying gas can be sprayed onto the cover support surface 96 using the drying nozzles 102. Simultaneously, or at a later time, the cover support surface 96 can be heated by the infrared diodes 112. In this regard, the cleaning head 98 can also rotate about a fourth axis of rotation D2. After the hollow body 94 has sufficiently dried, another hollow body 94 to be cleaned can be treated with the spear described in device 921. It should be noted at this point that the hollow body outer surface 35 and cover 52, not shown in FIG. 3, can be treated in a substantially similar manner.

[0068] 4A and 4B show a second embodiment of the proposed device 922 for cleaning a pot-like hollow body 94, with reference to a basic cross-sectional view. The basic difference with the embodiment of the device 921 shown in FIG. 3 is that the cleaning head 98 includes a flexible sheath 116 that can change from a contracted state (FIG. 4A) to an expanded state (FIG. 4B) and back again. Starting from the contracted state shown in FIG. 4A, cleaning fluid or drying gas is introduced into the flexible sheath 116 through the supply channel 68. The flexible sheath 116 is thereby filled with cleaning fluid or drying gas and, in so doing, continuously expands. The flexible sheath 116 continues to expand until the amount of cleaning fluid or drying gas supplied is equal to the amount leaving the flexible sheath 116 again through the cleaning nozzle 100, the drying nozzle 102, and / or another cleaning nozzle 100. For illustrative purposes, the cleaning nozzle 100, the drying nozzle 102, and / or the separate cleaning nozzle 108 are only shown in FIG. 4B . The flexible sheath 116 is now in an expanded state. The dimensions of the flexible sheath 116 in its expanded state can be selected within certain limits depending on the cleaning fluid or drying gas used and the temperature and pressure at which the cleaning fluid or drying gas is entrained within the flexible sheath 116. The cleaning fluid and drying gas flow along the hollow body inner surface 33 in the space intermediate the hollow body inner surface 33 and the cleaning head 98, preventing the flexible sheath 116 from contacting the hollow body inner surface 33. The flexible sheath 116 can also adapt to the course of the hollow body inner surface 33 within certain limits, especially in the area of ​​undercuts, resulting in a constant or approximately constant distance A that can be minimized, which is only possible with the limitations of a rigid cleaning head 98. As mentioned, distance A is 10 to 30 mm with a rigid cleaning head 98. This distance A can be further reduced using the flexible sheath 116. As mentioned, a strong and clearly directed flow of cleaning fluid and / or drying gas can be generated in the space intermediate the hollow body inner surface 33 and the cleaning head 98 over the short distance A, keeping the amount of cleaning fluid and drying gas required low. These advantages can be achieved to an even higher level using the flexible sheath 116.The flexible sheath 116 can, as mentioned, within certain limits adapt to the course of the hollow body inner surface 33. As a result, it is also possible to use the device for cleaning and / or drying hollow bodies 94 of various shapes without the need for changeover operations. [Explanation of symbols]

[0069] 10 Prior Art Devices 12 Hollow body 14. Case 16 Housing opening 18 Cover 20 Supporting wall 22 Process Space 24 Passage opening 26 Locking Device 28 Passage Hole 30 Transport Container 32 Bottom wall 33 Inner surface of hollow body 34 Side wall 35 Hollow body outer surface 36 Opening 37 Support wall section 38 Peripheral Surface 39 Contact surface 40 Cleaning Device 41 First Channel 42 First cleaning head 44 Wall section 46 Cleaning opening 48 Closed body 50 acceptance units 52 Cover 54 Inside of cover 56 Outer surface of cover 58 Alternate First Cleaning Head 64 Second Cleaning Head 66 Fluid guide unit 68 first supply channel 70 first discharge flow path 72 first end 76 Second discharge flow path 78 First cleaning nozzle 80 Another first cleaning nozzle 82 Second cleaning nozzle 83 Tubular body 84 Secondary flow path 86 First Drying Nozzle 88 Another first drying nozzle 90 Second Drying Nozzle 92 Proposed Devices Devices proposed by 921 and 922 94 Hollow body 96 Cover support surface 98 Cleaning Head 100 cleaning nozzle 102 Drying nozzle 104 Setting Device 106 Combined Unit 108 Another cleaning nozzle 110 Another drying nozzle 112 Infrared diode 114 Particle measurement devices 116 Flexible sheath α Spray angle A. Distance D1 First rotation axis D2 Second rotation axis D3 Third rotation axis D4 Fourth rotation axis

Claims

1. A device (92) for cleaning a pot-shaped hollow body (94), in particular a transport container (30) for semiconductor wafers or EUV lithography masks, said hollow body (94) comprising: a bottom wall (32) and one or more side walls (34) forming the hollow body inner surface (33); an opening (36) located opposite said bottom wall (32) and surrounded by said side wall (34); a cover support surface (96) formed by said side walls (34) and on which a cover (52) can be placed to close said hollow body (94); and wherein the device (92) comprises: a support wall (20) on which said hollow body (94) can rest; at least one passage opening (24) formed by said support wall (20); a cleaning device (40) capable of discharging a cleaning fluid for cleaning said cover support surface (96) when said hollow body (94) is placed on said support wall (20); and wherein the cleaning device (40) comprises: protruding above the passage opening (24) and / or capable of being captured within the hollow body (94) when the latter is placed on the support wall (20); and a plurality of cleaning nozzles (100) capable of spraying the cleaning fluid onto the cover support surface (96); A device (92) comprising a cleaning head (98).

2. The cleaning head (98) includes a plurality of drying nozzles (102) capable of dispersing drying gas onto the cover support surface (96).

2. The device (92) of claim 1, characterized in that:

3. The cleaning head (98) is rotatably and / or translatably movable.

3. The device (92) according to claim 1 or 2, characterized in that:

4. The cleaning head (98) is provided with a setting device (104) that can eject the cleaning fluid and / or the drying gas at a spray angle (α), and that can cooperate with the cleaning nozzle (100) and / or the drying nozzle (102) to set the spray angle (α). A device (92) according to any one of claims 1 to 3 or according to claim 2 or 3, characterized in that

5. The cleaning head (98) includes a plurality of infrared diodes (112) capable of heating the cover support surface (96).

5. A device (92) according to any one of claims 1 to 4, characterized in that:

6. The cleaning head (98) has an outer shape that at least approximately follows the course of the hollow body inner surface (33) so that the distance between the hollow body inner surface (33) and the cleaning head (98) is constant or approximately constant.

6. A device (92) according to any one of claims 1 to 5, characterized in that:

7. The device (92) comprises at least one coupling unit (106) for coupling acoustic waves into the cleaning fluid.

7. A device (92) according to any one of claims 1 to 6, characterized in that:

8. The device (92) comprises a first discharge flow path (70) having a first end (72), the first end (72) of the first discharge flow path (70) being in fluid communication only with the passage opening (24), through which the cleaning fluid discharged from the cleaning device (40) can be discharged, and a particle measuring device (114) is disposed in the discharge flow path (70) for determining particles contained in the cleaning fluid.

8. A device (92) according to any one of claims 1 to 7, characterized in that:

9. The cleaning head (98) comprises a plurality of separate cleaning nozzles (108) for cleaning the hollow body inner surface (33).

9. A device (92) according to any one of claims 1 to 8, characterized in that:

10. The cleaning head (98) includes a flexible sheath (116) that can be changed from a contracted state to an expanded state and back again by the cleaning fluid and / or the drying gas.

10. The device (92) according to any one of claims 1 to 9, characterized in that

11. 11. A method for cleaning a pot-like hollow body (94), in particular a transport container for semiconductor wafers or EUV lithography masks, using a device (92) according to any one of claims 1 to 10, said method comprising the steps of: - placing said hollow body (94) on said support wall (20); - ejecting the cleaning fluid for cleaning the cover support surface (96) by a plurality of cleaning nozzles (100) arranged on the cleaning head (98) of the cleaning device (40) so that the cleaning fluid is sprayed onto the cover support surface (96); - discharging said cleaning fluid through said first discharge channel (70); A method comprising:

12. The method comprises: - determining particles contained in the cleaning fluid using the particle measuring device (114) arranged in the outlet channel (70); - terminating the delivery of said cleaning fluid when a particle-related threshold is exceeded or below. The method of claim 11 , comprising:

13. The method comprises: - completely filling the space enclosed by the hollow body inner surface (33) with a first cleaning fluid; - coupling acoustic waves into said first cleaning fluid using a coupling unit (106); 13. The method of claim 11 or 12, comprising:

14. The method comprises: - cleaning said cover support surface (96) using said cleaning nozzle (100); - cleaning the hollow body inner surface (33) at different times using the different cleaning nozzles (108); 14. The method of any one of claims 11 to 13, comprising:

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