Method for cleaning pot-shaped hollow bodies, in particular transport containers for semiconductor wafers or lithography masks, with a corresponding device

Abstract

The invention relates to a method for cleaning pot-like hollow bodies 12, in particular transport containers for semiconductor wafers or lithography masks, with a corresponding device 10, comprising: - dispensing a first cleaning fluid for cleaning the hollow body inner surface 33 by a first dispensing unit 43; - discharging a first cleaning fluid by a first discharge channel 70, the first cleaning fluid having a first surface tension; - dispensing by a first dispensing unit 43 a second cleaning fluid for cleaning the hollow body inner surface 33, the second cleaning fluid being miscible with the first cleaning fluid, such that a mixture formed by the first cleaning fluid and the second cleaning fluid has a mixture surface tension lower than the first surface tension; - discharging the mixture through the first discharge channel 70 or through another discharge channel.

Description

[Technical Field]

[0001] The invention relates to a method for cleaning pot-like hollow bodies, in particular transport containers for semiconductor wafers or lithography masks, with a corresponding device. [Background technology]

[0002] The manufacture of highly integrated electronic circuits and other sensitive semiconductor components today takes place in factories where so-called semiconductor wafers pass through numerous processing steps. Most of these processing steps are painstakingly carried out in clean rooms that are kept contaminant-free, especially particulate and gaseous contaminants (AMC). Such complex processing is necessary because particulate and gaseous contaminants that come into contact with the semiconductor material of semiconductor wafers can affect, among other things, the material properties of the semiconductor wafers, resulting in entire production batches becoming defective and unusable, and having to be scrapped.

[0003] As the integration density of semiconductor circuits increases dramatically and the size of clean rooms increases, the effort required to maintain clean conditions increases exponentially. Therefore, maintaining clean conditions is becoming even more important. Therefore, semiconductor wafers are no longer 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 square bottom. The inserted semiconductor wafers can be transported from one clean room protected from the environment to another clean room while the FOUP cover is closed. When the FOUP reaches the processing station, the FOUP 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] Due to the long production downtime caused by semiconductor wafer contamination, FOUPs must be cleaned from time to time. FOUPs are primarily contaminated by wear debris from semiconductor wafers during loading and unloading into the FOUP, and by AMC resulting from previous processes.

[0005] The same applies to the transport containers for lithography masks, especially EUV (extreme ultraviolet radiation) 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 lithography masks.

[0006] Devices for cleaning FOUPs are known, for example, from U.S. Pat. No. 5,238,503, U.S. Pat. Appl. Pub. No. 2002 / 0046760, U.S. Pat. Appl. Pub. No. 2003 / 0102015, WO 2022 / 096657, WO 2005 / 001888, and EP 1 899 084.

[0007] In such cleaning devices, the FOUP is cleaned, at least on its inner surface, and optionally also on its outer surface. FOUPs are typically made of plastic, which means that the inner and outer surfaces, but also other surfaces, are not microscopically smooth. Rather, microscopic irregularities exist on such surfaces. Microcracks may also form. The cleaning fluid used for cleaning is typically water-based. Correspondingly small particles and / or AMCs may accumulate in and detach from the recesses and microcracks during operation of the FOUP, thereby undesirably affecting the material properties of the semiconductor wafers described above. However, the cleaning fluid used does not reach these microscopic recesses and microcracks, particularly due to surface tension. Even if this cleaning process is performed over a long period of time, at least some of the particles and AMCs cannot be removed from the microscopic recesses and microcracks. Therefore, it is not possible to prevent these particles and AMCs from undesirably affecting the material properties of the semiconductor wafers described above. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 5,238,503 [Patent Document 2] US Patent Application Publication No. 2002 / 0046760 [Patent Document 3] U.S. Patent Application Publication No. 2003 / 0102015 [Patent Document 4] International Publication No. 2022 / 096657 [Patent Document 5] International Publication No. 2005 / 001888 [Patent Document 6] European Patent No. 1899084 Summary of the Invention [Problem to be solved by the invention]

[0009] The aim of one embodiment of the present invention is to propose a method for cleaning pot-like hollow bodies, which makes it possible to remedy the above-mentioned drawbacks by simple and inexpensive means, and in particular to also make it possible to remove particles and AMCs that have accumulated in micro-cracks and micro-depressions on the surface of the FOUP.

[0010] This object is achieved by the features specified in claim 1. Advantageous embodiments are the subject matter of the dependent claims. [Means for solving the problem]

[0011] An embodiment of the invention is a method for cleaning pot-like hollow bodies, in particular transport containers for semiconductor wafers or lithography masks, in a corresponding device, comprising: -Hollow body one or more side walls forming an inner surface of the hollow body; an opening surrounded by a sidewall; -Devices a cleaning device having a first discharge unit capable of discharging a first cleaning fluid and a second cleaning fluid for cleaning the inner surface of the hollow body; a first discharge flow path through which the first cleaning fluid and the second cleaning fluid discharged by the cleaning device can be discharged; -The method is discharging a first cleaning fluid for cleaning the inner surface of the hollow body by a first discharging unit; discharging a first cleaning fluid through a first discharge channel, the first cleaning fluid having a first surface tension; discharging a second cleaning fluid by a first discharging unit for cleaning the inner surface of the hollow body, the second cleaning fluid being miscible with the first cleaning fluid, such that a mixture formed by the first cleaning fluid and the second cleaning fluid has a mixture surface tension lower than the first surface tension; and discharging the mixture through the first discharge flow path or through another discharge flow path.

[0012] First, the inner surface of the hollow body is cleaned with a first cleaning fluid capable of removing the majority of all impurities. The first cleaning fluid is then removed from the cleaning device, particularly from the hollow body. However, a certain amount of the first cleaning fluid remains on the inner surface of the hollow body. Depending on the cleaning fluid used, this portion evaporates relatively quickly, but the impurities contained in this portion remain concentrated and localized. This is particularly true for minute depressions on the inner surface of the hollow body. Over time, these impurities may detach from the inner surface of the hollow body and have the aforementioned harmful effects on semiconductor wafers transported within the hollow body.

[0013] According to the invention, it is not necessary to wait until the residue of the first cleaning fluid has evaporated, but rather a second cleaning fluid can be sprayed onto the interior of the hollow body and mixed with the first cleaning fluid, which can be sprayed onto the interior of the hollow body in advance, when the first cleaning fluid has not yet been removed.

[0014] The second cleaning fluid is selected so that the resulting mixture has a surface tension lower than the first surface tension of the first fluid. The mixture is then removed from the hollow body. It has been shown that the mixture can be removed from the hollow body substantially without residue. This prevents impurities from concentrating due to evaporation and remaining locally on the interior surface of the hollow body, as described above. Overall, this significantly improves cleaning results compared to cleaning with only the first cleaning fluid, and further reduces the number of semiconductor wafer production batches that must be rejected due to contamination originating from the hollow body. While it is desirable, particularly for design reasons, to discharge both the first cleaning fluid and the mixture using the same first outlet flow path, it may also make sense to discharge the mixture using a separate outlet flow path.

[0015] According to a further embodiment, the second cleaning fluid is sprayed onto the inner hollow surface in a vapor state, and it has been shown that providing the second cleaning fluid in a vapor state leads to improved cleaning results compared to providing it in a liquid state.

[0016] In a further developed embodiment, water is used as the first cleaning fluid and an organic solvent is used as the second cleaning fluid, the term "organic solvent" being understood to mean a carbon-containing chemical used to dissolve other substances such as paints, varnishes, greases, oils, etc.

[0017] Water is cheap, available and easy to handle. The use of organic solvents has proven suitable for achieving satisfactory cleaning results.

[0018] In a further embodiment, the organic solvent has a water solubility of at least 1 g / L and a vapor pressure of 25 Pa to 25000 Pa. Particularly good cleaning results can be achieved in these water solubility and vapor pressure ranges.

[0019] In a further embodiment, the second cleaning fluid is mixed with a carrier gas before being mixed with the first cleaning fluid. Nitrogen, for example, can be used as the carrier gas, particularly because it is inert. In this way, the second cleaning fluid can be safely delivered to the interior of the hollow body in the desired amount and concentration.

[0020] A further developed embodiment is the cleaning device comprises a second discharge unit capable of discharging a first cleaning fluid and a second cleaning fluid for cleaning the outer surface of the hollow body; The device may be characterized in that it comprises a second discharge channel through which the first cleaning fluid discharged by the second discharge head can be discharged.

[0021] The method is: Discharging a first cleaning fluid by a second discharging unit to clean the outer surface of the hollow body; Discharging the first cleaning fluid through the first discharge channel and / or the second discharge channel; Discharging a second cleaning fluid by a second discharging unit to clean the outer surface of the hollow body; Discharging the second cleaning fluid through the first discharge flow path and / or the second discharge flow path.

[0022] It is true that cleaning the outer surface of the hollow body, which is usually more contaminated than the inner surface, is not very important for the number of defective semiconductor wafers because, as long as the hollow body is sealed with a cover, contamination originating from the outer surface of the hollow body cannot reach the semiconductor wafers placed inside the hollow body. However, thorough cleaning of the outer surface of the hollow body can also contribute to reducing the number of defective semiconductor wafers. The technical effects that can be achieved by using the first and second cleaning fluids on the outer surface of the hollow body are consistent with the effects described for cleaning the inner surface of the hollow body.

[0023] According to a further developed embodiment the first cleaning fluid dispensed by the first dispense unit and the mixture dispensed by the first dispense unit are exclusively dispensed through the first dispense flow path; The first cleaning fluid dispensed by the second dispense unit and the mixture dispensed by the second dispense unit are exclusively dispensed through the second dispensing flow path.

[0024] In this embodiment, the device is configured to ensure strict separation of the first and second cleaning fluids used to clean the interior of the hollow body, on the one hand, and the first and second cleaning fluids used to clean the exterior surface of the hollow body, on the other hand. As a result, the first and second cleaning fluids used to clean the interior of the hollow body, and the resulting mixture, respectively, are not contaminated with particulates and AMCs originating from the exterior surface of the hollow body, thereby effectively cleaning the interior of the hollow body. The time required to clean the interior of the hollow body can be significantly reduced compared to devices known from the prior art. In addition, the amount of first cleaning fluid required to clean the interior of the hollow body is also reduced.

[0025] It should also be emphasized that the first and second cleaning fluids used to clean the interior of the hollow body are discharged through the first outlet flow path, and the first and second cleaning fluids used to clean the exterior surface of the hollow body are discharged through the second outlet flow path without being mixed, at least within the device. As mentioned above, the interior surface of the hollow body is typically less contaminated than the exterior surface of the hollow body, so the first and second cleaning fluids used to clean the interior surface of the hollow body contain fewer particulates and AMCs after cleaning than the first and second cleaning fluids used to clean the exterior surface of the hollow body. Therefore, after cleaning the interior of the hollow body, the first and second cleaning fluids can also be used to clean the exterior surface of the hollow body. As a result, the amount of cleaning fluid used can be reduced.

[0026] In a further embodiment, the hollow body comprises a cover capable of closing the opening, the cover having an inner cover surface and an outer cover surface; the device comprises a cleaning opening that can be at least partially closed by a closure body, the closure body comprising a receiving unit for receiving a cover of the hollow body, The cleaning device comprises a further first dispensing unit that is able to spray the first cleaning fluid and the second cleaning fluid onto the inner surface of the cover for cleaning when the cleaning opening is closed by the closure or cover.

[0027] It may be appropriate for the method to include the following steps: moving the closure to an open position; - placing the cover on the receiving unit of the closure using the cover outer surface and releasably securing the cover on the closure; moving the closure to a closed position; and Discharging a first cleaning fluid and a second cleaning fluid for cleaning the inner surface of the cover using another first discharging unit.

[0028] The embodiment of the method described so far relates to cleaning the interior and exterior surfaces of a hollow body. As mentioned, the FOUP is closed with a removable cover. However, just as particulates and AMC can accumulate on the interior surface of the cover, in particular on the interior surface of the hollow body, which can have a negative impact on the production of semiconductor wafers. In this embodiment, however, the device includes a separate first dispensing unit capable of cleaning the interior surface of the cover. For this purpose, the same first and second cleaning fluids are preferably used as are used for cleaning the interior surface of the hollow body. However, if deemed necessary, different first and second cleaning fluids can also be used, as long as the conditions set forth at the beginning regarding the properties of the first and second cleaning fluids are met.

[0029] In this way, particles and AMC on the inner surface of the cover can also be removed. To prevent the first and second cleaning fluids from flowing out of the cleaning openings uncontrolled, the cleaning openings must be sealed during the cleaning process. For this purpose, either the cover or the closure interacts with another wall portion so that the cleaning openings are tightly sealed. The cleaning openings can be arranged so that particles and AMC from the surroundings of the hollow body do not enter the first and second cleaning fluids during the cleaning process. The first and second cleaning fluids are preferably discharged via a first discharge channel. In this case, the receiving unit of the closure interacts with the outer surface of the cover, allowing unimpeded access to the inner surface of the cover, in particular for the first and second cleaning fluids.

[0030] Exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a schematic diagram of a first embodiment of a device for cleaning pot-shaped hollow bodies, in particular transport containers for semiconductor wafers or EUV lithography masks; FIG. [Figure 2] 1 is a cross-sectional view showing the principle of a second embodiment of a device for cleaning pot-shaped hollow bodies; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0032] 1 shows an embodiment of the proposed device 101 for cleaning pot-like hollow bodies 12 with reference to a basic cross section. The device 101 has a housing 14 forming a support wall 20. The support wall 20 forms a passage opening 24, a locking device 26 being arranged radially outside the passage opening 24.

[0033] Once the cover material 18 has been removed, the hollow body 12, in particular a transport container 30 for semiconductor wafers, also known as FOUP, or a transport container 30 for lithography 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 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.

[0034] 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.

[0035] 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 .

[0036] The device 101 is further equipped with a cleaning device 40 having a first discharge unit 43 embodied as a first cleaning head 42 protruding above the passage opening 24 and 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.

[0037] 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.

[0038] 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.

[0039] The receiving unit 50 is designed in the illustrated embodiment to interact with the cover 52 only via the cover outer surface 56 .

[0040] The cleaning device 40 is further equipped with another first dispensing unit 59 embodied as another first cleaning head 58 which is arranged in the vicinity of the closure body 48 when the closure body 48 is in the closed position.

[0041] In the illustrated embodiment, the first cleaning head 42 is not movable, but it can also be designed to be rotatable and / or translatable.

[0042] The device 101 further comprises a fluid directing unit 66 having a first supply channel 68 by which the first cleaning fluid and the second cleaning fluid can be directed to the first cleaning head 42 and to the further first cleaning head 58.

[0043] The first cleaning fluid has a first surface tension, and the second cleaning fluid is selected to be miscible with the first cleaning fluid, and the first and second cleaning fluids are further selected such that a mixture of the first and second cleaning fluids has a mixture surface tension that is lower than the first surface tension of the first cleaning fluid.

[0044] Furthermore, the fluid directing unit 66 comprises a first discharge channel 70 through which the first cleaning fluid and the second cleaning fluid or the resulting mixture discharged from the first cleaning head 42 and from the other first cleaning head 58 can be discharged again. The first discharge channel 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 channel 70 is expanded in a funnel-like manner towards the first end 72 and is connected to the support wall 20 so that the first end 72 of the first discharge channel 70 is flush with the passage opening 24. The first discharge channel 70 annularly surrounds the first supply channel 68.

[0045] To discharge the first and second cleaning fluids used to clean the cover inner surface 54, the first discharge flow path 70 has a secondary flow path 84 that opens into the first discharge flow path 70 in a manner not shown in detail.

[0046] A first particle measuring device 741 is arranged in the first discharge flow path 70, which is able to determine, and in particular count, particles present in the first and second cleaning fluids used to clean the hollow body inner surface 33. In addition, a second particle measuring device 742 is arranged in the secondary flow path 84, which is able to determine, and in particular count, particles present in the first and second cleaning fluids used to clean the cover inner surface 54.

[0047] 2 also shows a cross-sectional view illustrating the principle of a second embodiment of device 102. The basic structure of the device according to the second embodiment is almost identical to that of device 101 according to the first embodiment, so only the essential differences will be described below.

[0048] In the second embodiment of the device 102, the housing 14 defines a housing opening 16, which can be closed by a covering 18 that can be removed from the housing 14. When the housing opening 16 is closed, a process space 22 is defined, which is bounded by the support wall 20, by the housing 14 itself, and by the covering 18. Radially outward from the locking device 26, the support wall 20 of the second embodiment example of the device 102 is provided with two passage holes 28 that open into the process space 22.

[0049] The cleaning device 40 further comprises a second discharge unit 63 having a substantially U-shaped second cleaning head 64 arranged at least partially within the process space 22. However, unlike the first cleaning head 42, the second cleaning head 64 is arranged outside the hollow body 12 when the hollow body 12 is connected to the support wall 20. The second cleaning head 64 is rotatable about a second rotation axis D2, 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.

[0050] A detailed illustration of the second supply flow paths for supplying the first and second cleaning fluids to the second cleaning head 64 has been omitted for illustrative purposes, but the design of the second supply flow paths should be readily apparent to one skilled in the art.

[0051] The fluid conducting unit 66 further comprises a second discharge channel 76, which is designed substantially identically to the first discharge channel 70, but which 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. An embodiment in which a separate particle measurement device 74 is arranged in the second discharge channel 76 is not shown. At this point, it should be pointed out that the fluid conducting unit 66 is only shown in principle in FIG. 2. The illustration of the fluid conducting unit 66 in FIG. 2 does not claim to be accurate, since many channels are nested and arranged at different levels. However, a person skilled in the art will be able to easily deduce at least the functional design of the fluid conducting unit 66 from FIG. 1.

[0052] From the above, it can be seen that the device 102 according to the second embodiment is essentially an extension of the device according to the first embodiment of the device 101. In the following, the mode of operation of the device 102 according to the second embodiment will be described, from which the mode of operation of the device 101 according to an example of the first embodiment can also be derived.

[0053] In a starting state, not shown here, the covering material 18 is open and the second cleaning head 64 is rotated 90° relative to Fig. 2 so that the U-shaped portion of the second cleaning head 64 is perpendicular to the plane of Fig. 2. The closure 48 is in an open position with the closure 48 aligned approximately horizontally relative to Fig. 2.

[0054] The cover 52 is detached from the hollow body 12 by a not-shown handling device, e.g., a robotic gripper, and placed on the receiving unit 50. As shown in FIGS. 1 and 2, the open hollow body 12 is placed on the support wall 20 using the peripheral surface 38. The hollow body 12 is then locked by the locking unit 26, which connects and thus attaches the hollow body 12 to the support wall 20. In this regard, the locking device 26 is equipped with a sealing agent, not shown here, which seals the hollow body 12 against the support wall 20. The housing opening is now closed by the covering material 18. In addition, the receiving unit 50 of the closure body 48 is actuated so that the cover 52 is attached to the closure body 48. The closure body 48 is rotated by 90° to the closed position, as shown in FIGS. 1 and 2. The cover 52 now seals the cleaning opening 46.

[0055] The first cleaning fluid is then guided via the first supply passage 68 to the first cleaning head 42 and discharged by the first cleaning nozzle 78, resulting in the first cleaning fluid cleaning the hollow body inner surface 33. The other first cleaning head 58 includes another first cleaning nozzle 80 that sprays the first cleaning fluid onto the cover inner surface 54, resulting in the cover inner surface 54 being cleaned.

[0056] The first cleaning fluid dispensed by the first cleaning head 42 and sprayed onto the hollow body inner surface 33 is supplied via a first discharge channel 70. The same applies to the first cleaning fluid dispensed by the other first cleaning head 58 and sprayed onto the cover inner surface 54.

[0057] At the same time, the first cleaning fluid is directed via a second supply channel (not shown) to the second cleaning head 64, where it is ejected from the second cleaning nozzles 82 to clean the hollow body outer surface 35. In this regard, the second cleaning head 64 can rotate about a second rotation axis D2. The second cleaning fluid ejected by the second cleaning head 64 and sprayed onto the hollow body outer surface 35 is discharged via a second discharge channel 76.

[0058] The first cleaning nozzle 78, the further first cleaning nozzle 80, and the second cleaning nozzle 82 can be configured so that the spray angle α at which the first cleaning fluid is discharged can be set. For this purpose, the first cleaning nozzle 78, the further first cleaning nozzle 80, and the second cleaning nozzle 82 can be supported in a spherical head shape. Alternatively or additionally, the first cleaning nozzle 78 can be arranged on a tubular body 83 rotatable about a third rotation axis D3 so that the spray angle α can be set. The first cleaning head 42 is equipped with at least a setting device 85 that can set the spray angle α. The further first cleaning nozzle 80 and the second cleaning nozzle 82 can be configured correspondingly, and the spray angle α at which the first cleaning fluid is discharged by the further first cleaning nozzle 80 can be set by the setting device 85 as well. The setting device 85 can also be configured so that the spray angle α of the second cleaning nozzle 80 located on the second cleaning head 64 can be set in a similar manner. This can achieve that the first cleaning fluid impinges perpendicularly or nearly perpendicularly on the hollow body inner surface 33 and on the cover inner surface or hollow body outer surface 35 .

[0059] Furthermore, at least one coupling unit 87 is provided for coupling acoustic waves into the first cleaning fluid. In the illustrated embodiment, several coupling units 87 are integrated into at least some of the first cleaning nozzles 78, which are designed as so-called "megasonic nozzles". Megasonic waves can be coupled into the first cleaning fluid discharged by the first cleaning nozzles 78. The same are provided correspondingly for the further first nozzles 80 and the second cleaning nozzles 82.

[0060] The first cleaning nozzles 78 can be opened and closed independently of each other. Therefore, it is possible to clean various parts of the hollow body inner surface 33 first and other parts later. For example, parts that are historically less soiled can be cleaned first, and parts that are historically more soiled can be cleaned later. The separate first cleaning nozzle 80 and second cleaning nozzle 82 can be designed to correspond to each other so that the cover inner surface 54 and the hollow body outer surface 35 can be cleaned correspondingly.

[0061] Particles and AMCs present on the hollow body inner surface 33 and the cover inner surface 54 are removed by the first cleaning fluid. Particles originating from the hollow body inner surface 33 are detected by the first particle measuring device 741, and particles originating from the cover inner surface 54 are detected by the second particle measuring device 742. In this regard, the first particle measuring device 741 and the second particle measuring device 742 are configured to determine the number of particles passing through the particle measuring device 74 at a given volumetric flow rate within a certain period of time. This allows for determining whether the hollow body inner surface 33 and the cover inner surface 54 have been cleaned to a desired extent. For example, if the hollow body inner surface 33 is sufficiently clean, the cleaning process of the hollow body 12 can be terminated while the cleaning process of the cover inner surface 54 continues. Meanwhile, the hollow body 12 can be removed from the device 102 by a robotic gripper, thereby saving time.

[0062] Not shown is an embodiment in which the particle measurement device 74 is located downstream of the opening of the secondary flow path 84 into the first discharge flow path 70. In this case, it is not possible to distinguish whether the particles originate from the cover inner surface 54 or the hollow body inner surface 33. Nevertheless, the cleaning process can be stopped if the number of particles falls below a certain level.

[0063] Cleaning of the hollow body inner surface 33 and the cover inner surface 54 is generally more important than cleaning of the hollow body outer surface 35. When it is determined that 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 treated.

[0064] After the first cleaning fluid has been sprayed onto both the hollow body inner surface 33 and the hollow body outer surface 35, as well as onto the cover inner surface 54, the first cleaning fluid is removed from the hollow body 12 in the manner described above. It should be noted that, depending on the first cleaning fluid used, residues may remain within the hollow body 12. The second cleaning fluid is then sprayed onto the hollow body outer surface 35, the hollow body inner surface 33, and the cover inner surface 54 essentially in the same manner as the first cleaning fluid. The second cleaning fluid can be mixed with a carrier gas; for this purpose, a mixing device (not shown) can be used. The carrier gas can be, for example, nitrogen.

[0065] Due to the described properties of the first and second cleaning fluids with regard to miscibility and surface tension, the resulting mixture of the first and second cleaning fluid residues can be removed almost residue-free from the hollow body 12 without leaving locally concentrated impurities, in this regard the cleaning process can be interrupted at this point.

[0066] The first and second cleaning fluids, or the resulting mixture, discharged by the second cleaning head 64 and sprayed onto the hollow body exterior surface 35 are discharged through the second discharge channel 76. As a result, the first and second cleaning fluids, or the resulting mixture, used to clean the hollow body exterior surface 35 are discharged separately from those used to clean the hollow body interior surface 33. As a result, particulates and AMC generated from the hollow body exterior surface 35 cannot reach the hollow body interior surface 33 or the cover interior surface 54.

[0067] Purely optionally, a first drying gas and a second drying gas, e.g., air or nitrogen, can be supplied to the first cleaning head 42, the further first cleaning head 58, and the second cleaning head 64 via the first supply channel 68 or a second supply channel (not shown), substantially similar to the first cleaning fluid and the second cleaning fluid. The first cleaning head 42 is equipped with a first drying nozzle 86, the further first cleaning head 58 is equipped with another first drying nozzle 88, and the second cleaning head 64 is equipped with a second drying nozzle 90, which can discharge the first drying gas or the second drying gas and spray it 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, or the resulting mixture, from the device 102. Residues of the first cleaning fluid and the second cleaning fluid can also be blown away.

[0068] The first cleaning head 42, the further first cleaning head 58, and the second cleaning head can each be further heated by an infrared diode 92, which can heat and evaporate residues of the first cleaning fluid and the second cleaning fluid, so that the residues can be removed from the device 102 by the first drying gas and the second drying gas.

[0069] After the drying process is completed, the covering material 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.

[0070] The hollow body 12 can now be placed in a vacuum chamber (not shown), for which purpose the cover 52 is again separated from the hollow body 12. A vacuum is then applied to the hollow body 12, in particular to the hollow body inner surface 33, the cover inner surface 54 and the hollow body outer surface 35, so that the residues of the mixture of the first and second cleaning fluids can be evaporated.

[0071] At this point, the next hollow body 12 to be cleaned can be handled in the device 102 in the manner described. [Explanation of symbols]

[0072] 101 devices 102 devices 12 Hollow body 14. Case 16 Housing opening 18 Cover material 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 38 Peripheral Surface 40 Cleaning Device 42 First cleaning head 43 First discharge unit 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 59 Another first discharge unit 63 Second Discharge Unit 64 Second Cleaning Head 66 Fluid guide unit 68 first supply channel 70 first discharge flow path 72 first end 74 Particle Measurement Device 741, 742 Particle measurement device 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 85 Setting Device 86 First Drying Nozzle 87 Combined Unit 88 Another first drying nozzle 90 Second Drying Nozzle 92 Infrared diode α Spray angle D1 First rotation axis D2 Second rotation axis D3 Third rotation axis

Claims

1. A method for cleaning pot-like hollow bodies (12), in particular transport containers for semiconductor wafers or lithography masks, in a corresponding device (10), comprising: said hollow body (12) one or more side walls (34) forming the hollow body inner surface (33); an opening (36) surrounded by said side wall (34); said device (10) comprising: a cleaning device (40) having a first discharge unit (43) capable of discharging a first cleaning fluid and a second cleaning fluid for cleaning the hollow body inner surface (33); a first discharge flow path (70) through which the first and second cleaning fluids discharged by the cleaning device (40) can be discharged, said method comprising: - discharging a first cleaning fluid by the first dispensing unit (43) for cleaning the hollow body inner surface (33); - discharging the first cleaning fluid through the first discharge channel (70), the first cleaning fluid having a first surface tension; - dispensing by the first dispensing unit (43) a second cleaning fluid for cleaning the hollow body inner surface (33), the second cleaning fluid being miscible with the first cleaning fluid, such that a mixture formed by the first cleaning fluid and the second cleaning fluid has a mixture surface tension lower than the first surface tension; - Discharging the mixture through the first discharge flow path (70) or through another discharge flow path.

2. The second cleaning fluid is sprayed onto the inner hollow surface body (33) in a vapor state. The method of claim 1.

3. The first cleaning fluid is water, and the second cleaning fluid is an organic solvent.

3. The method according to claim 1 or 2.

4. The organic solvent has a water solubility of at least 1 g / L and a vapor pressure of 25 Pa to 25,000 Pa. The method of claim 3.

5. The second cleaning fluid is mixed with a carrier gas before being mixed with the first cleaning fluid.

5. The method according to any one of claims 2 to 4.

6. - said cleaning device (40) comprises a second discharge unit (63) capable of discharging said first and second cleaning fluids to clean said hollow body outer surface (35); - said device (10) comprises a second discharge channel (76) capable of discharging said first cleaning fluid discharged by said second discharge head (63); said method comprising: - discharging by the second dispensing unit (63) the first cleaning fluid for cleaning the hollow body outer surface (35); - discharging the first cleaning fluid through the first discharge channel (70) and / or the second discharge channel (76); - discharging by the second dispensing unit (63) the second cleaning fluid for cleaning the hollow body outer surface (35); - discharging the second cleaning fluid by the first discharge channel (70) and / or the second discharge channel (76), 6. The method according to any one of claims 1 to 5.

7. the first cleaning fluid discharged by the first discharge unit (43) and the mixture discharged by the first discharge unit (43) are discharged exclusively through the first discharge channel (70); the first cleaning fluid discharged by the second discharge unit (63) and the mixture discharged by the second discharge unit (63) are discharged exclusively through the second discharge channel (76); characterized in that The method of claim 6.

8. - said hollow body (12) comprises a cover (52) capable of closing said opening (36) and having an inner cover surface (54) and an outer cover surface (56); - said device (10) comprises a cleaning opening (46) that is at least partially closable by a closure (48), said closure (48) comprising a receiving unit (50) for receiving said cover (52) of said hollow body (12); the cleaning device (40) comprises a further first dispensing unit (59) capable of dispensing the first cleaning fluid and the second cleaning fluid onto the cover inner surface (54) for cleaning when the cleaning opening (46) is closed by the closure (48) or the cover (52); said method comprising: - moving said closure (48) to an open position; - placing the cover (52) onto the receiving unit (50) of the closure (48) using the cover outer surface (56) to releasably secure the cover (52) onto the closure (48); - moving the closure (48) to a closed position; - dispensing the first and second cleaning fluids for cleaning the cover inner surface (54) using the separate first dispensing unit (59), 8. The method according to any one of claims 1 to 7.

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