Method and cleaning station for a transport enclosure for the conveying and atmospheric storage of semiconductor substrates

Abstract

A cleaning method (100) for a transport enclosure (2) for the conveying and atmospheric storage of semiconductor substrates comprising the following succession of steps: - a first wetting step (101) during which the internal walls of a shell (3) of the transport enclosure (2) are wetted with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.0001m3 / m2), - a subsequent second dewetting step (102) by projection of a pressurized gas jet, during which the piloting of an articulated arm (23) is controlled to move the gas projection device (26) in the shell (3) along a trajectory and orientation of the gas jet so that the pressurized gas jet carries the liquid deposited on the internal walls out of the shell (3). Abbreviated figure: Figure 1

Description

Title of the invention: Method and station for cleaning a transport container for the conveying and atmospheric storage of semiconductor substrates Technical field of the invention

[0001] The present invention relates to a method and a cleaning station for a transport container for the conveying and atmospheric storage of semiconductor substrates such as semiconductor wafers. Technical background

[0002] Transport enclosures define a confined space under atmospheric pressure, separated from the external environment, for the transport and storage of one or more substrates. In the semiconductor manufacturing industry, these enclosures allow substrates to be transported from one piece of equipment to another or to be stored between two manufacturing steps.

[0003] These transport containers are made of plastic materials such as polycarbonate, which can in some cases concentrate contaminants, particularly organic or gaseous contaminants, including those released by the substrates. These contaminants can be very harmful to the substrates. Therefore, the containers (inside and out) are regularly cleaned by washing with a liquid such as pure water, generally using approximately four to seven liters of water per transport container. This method consumes a large quantity of ultrapure water considering the tens of thousands of transport containers regularly washed each year in each semiconductor manufacturing plant.

[0004] These wet cleaning steps require subsequent drying of the enclosures. Drying is generally achieved by rapid rotation of the enclosure and / or vacuuming, possibly combined with infrared radiation, which can be time-consuming, energy-intensive, cumbersome, and difficult to implement in an industrial semiconductor manufacturing process.

[0005] Some processes also offer drying by nitrogen blowing using fixed or rotating nozzles introduced inside the envelope and whose sequenced control of opening and closing several dozen valves makes it possible to target specific points in the envelope.

[0006] However, some areas inside the enclosure may remain difficult to access for the gas jets from the nozzles or for infrared radiation. This is particularly the case for areas located behind diffusers or reinforcements of the transport enclosure. where liquid can accumulate. Also, in the case of so-called "double-walled" enclosures, the internal shelves for storing the wafers are not molded with the outer casing but are attached to it with a difficult-to-access gap between the two. These processes then require subsequent vacuum-sealing steps to complete the drying process.

[0007] Furthermore, these solutions for drying by evaporation of liquid water, particularly by infrared heating, vacuum, or gas blowing, have the drawback that contaminant residues may appear on the surface of the chambers once the liquid has evaporated. Indeed, contaminant species trapped by water droplets, especially acids, can remain in place during drying by water evaporation, including during drying by heating, particularly by infrared radiation.

[0008] To reduce contamination in enclosures, a method of purging their internal atmosphere using a dry process, as described in document WO2021058303, has also been considered. An articulated robot arm carrying at least one injector is inserted into the rigid shell of the FOUP enclosure to sweep the interior with a dry gas or a mixture of gas and liquid water injected in a small proportion to allow for rapid evaporation. However, this drying process may not be suitable for certain contaminants requiring wet cleaning, i.e., with liquid water. Indeed, liquid water facilitates the removal of solid particles trapped in the surface texture of the walls or certain water-soluble chemical residues. Summary of the invention

[0009] One of the aims of the present invention is to propose a station and a method for cleaning the internal surfaces of the atmospheric transport enclosure using liquid water that is more efficient and faster than those of the prior art.

[0010] Another object of the present invention is to enable the drying of the internal walls of transport enclosures, including in hard-to-reach areas.

[0011] To this end, the invention relates to a method for cleaning a transport container for the conveying and atmospheric storage of semiconductor substrates in a cleaning station, said transport container comprising an enclosure having a front opening and a removable door for closing the front opening, the cleaning station comprising a robot having a six-axis articulated arm and a head arranged at one end of the articulated arm, said head carrying a gas projection device configured to project a pressurized gas jet, characterized in that once the transport container is opened, the cleaning method comprises the following succession of steps: - a first wetting stage during which the internal walls of the transport enclosure are wetted with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.0001m3 / m2), - a second successive dewetting stage by projection of a pressurized gas jet, during which the piloting of the articulated arm is controlled to move the gas projection device in the enclosure along a trajectory and orientation of the gas jet so that the pressurized gas jet carries the liquid deposited on the internal walls out of the enclosure.

[0012] The cleaning process thus comprises two distinct and successive steps for cleaning the internal walls of the transport container with liquid water. Because it is projected in very small quantities, this water can be expelled from the container by the entrainment of the pressurized gas jet, while still being sufficient to dissolve the contaminants in the water film. The droplets react, dissolve, and transport the particles and soluble chemical species, particularly acids, which are then rapidly dried or carried away from the container's outer shell. In other words, spraying a larger quantity of water onto the internal walls of the container does not improve their cleaning. On the contrary, projecting more water slows down the drying process and increases water consumption, which is hardly acceptable in production and is undesirable from an ecological and economic standpoint.With the cleaning process according to the invention, water consumption is significantly reduced compared to the amount of water used in prior art devices, in particular by a factor of one hundred. This small amount of projected water allows for rapid dewlogging of the walls by entrainment of the water film by a pressurized gas jet moved by means of the robot's articulated arm. Dewlogging by projecting a well-oriented pressurized gas jet allows the transport container's outer shell to dry by entrainment, with little or no water evaporation. Indeed, contaminants trapped by water droplets, particularly acids, can remain in place during drying by water evaporation, including by infrared radiation. In contrast, dewlogging is a mechanical removal of water, by entrainment with pressurized gas.This action allows for the complete removal of droplets and contaminants from the enclosure, preventing them from remaining on the walls after evaporation and saving time, as evaporation is relatively slow. This is made possible by the use of a six-axis articulated robot arm. Its maneuverability and speed allow the gas projection device to be inserted into the enclosure and moved along an optimized trajectory to push liquids and impurities out of the enclosure by entrainment against the internal walls without drying them in place.

[0013] The cleaning process may further include one or more of the features described below, taken alone or in combination.

[0014] In the first wetting stage, the liquid water can be projected in the form of a mist, in particular in droplets with dimensions less than 200 µm.

[0015] In the first wetting stage, liquid water can be projected by a liquid water projection device carried by the head of the robot.

[0016] The cleaning process may include a third successive purging step during which the closed transport container is purged by a dry purging gas.

[0017] The cleaning process may include a door cleaning step comprising: - a first wetting stage during which the inner wall of the transport enclosure door is wetted with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.0001m3 / m2), - a second successive dewetting stage by projection of a pressurized gas jet during which the articulated arm is controlled to move the gas projection device in relation to the door along a trajectory and orientation of the gas jet so that the pressurized gas jet carries the liquid deposited on the inner wall out of the door.

[0018] The invention also relates to a cleaning station for a transport container for the conveying and atmospheric storage of semiconductor substrates, characterized in that the cleaning station comprises: - a robot comprising a six-axis articulated arm and a head at one end of the articulated arm, said head carrying a gas projection device configured to project a pressurized gas jet, - a cleaning chamber receiving the robot and comprising an interface configured to couple a transport enclosure envelope to the cleaning chamber, - a door actuator arranged in the cleaning chamber configured to open and close the transport enclosure by moving a door of the transport enclosure away from or towards a front opening of the envelope, - a liquid water projection device configured to wet the internal walls of the transport enclosure envelope with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.0001m3 / m2), and - a control unit configured to implement a cleaning process as described above, in particular to control the piloting of the articulated arm in order to move the robot head in the envelope in the second dewetting stage.

[0019] The cleaning station may also include one or more of the features described below, taken alone or in combination.

[0020] The liquid water projection device includes, for example, at least one hydraulic nozzle, such as a hollow cone nozzle, carried by the head of the robot, for example two or three hydraulic nozzles.

[0021] The gas projection device includes, for example, at least one flat jet blow nozzle configured to produce a gas blade.

[0022] According to one embodiment, the angle formed between the plane of the flat jet of at least one flat jet blow nozzle and the axis of rotation of the end of the articulated arm is distinct from a zero angle, such as between 30° and 60°, such as 45°.

[0023] According to one embodiment, the robot head carries a presence sensor.

[0024] According to one embodiment, the cleaning station comprises a chamber buffer attached to the cleaning chamber and an external loading port for receiving a transport enclosure, the buffer chamber being interposed between the external loading port and the cleaning chamber, the interface having an internal loading port capable of coupling to the rigid casing of the transport enclosure to position it opposite an opening in the cleaning chamber, the external loading port being configured to deposit the transport enclosure onto the internal loading port and to take the transport enclosure from the internal loading port, the internal loading port being arranged in the buffer chamber.

[0025] The buffer chamber may include a purge device comprising movable nozzles and an actuator enabling the nozzles to be moved to be introduced or connected to ventilation ports of the transport enclosure located under the lower face of the casing.

[0026] The buffer chamber may include a displacement device configured to grasp the transport enclosure to move it towards or away from a storage shelf of the buffer chamber.

[0027] According to one embodiment, the interface includes a sealing gasket arranged around the opening of the cleaning chamber and at least one clamping jaw configured to hermetically couple the casing to the cleaning chamber by compressing the sealing gasket.

[0028] According to one embodiment, at least one clamping jaw comprises two linear actuators configured to drive a jaw in a respective direction, the directions of the two linear actuators being perpendicular to each other, one being intended to be parallel to a wall of the transport enclosure's casing.

[0029] The cleaning station may include a gas shower arranged in the cleaning chamber, the gas shower having one or more blow holes in the shape of an arc, ring or frame and through which the articulated arm of the robot can plunge to clean the head by blowing gas. Brief description of the figures

[0030] Other advantages and features will become apparent from the description of an illustrative but not limiting example of the present invention, as well as from the accompanying drawings in which:

[0031] [Fig-1] Fig. 1 represents a schematic view of a cleaning station with an enclosed transport enclosure coupled to an external loading port of said station.

[0032] [Fig.2] The [Fig.2] shows a perspective view of an envelope of the transport enclosure of the [Fig.1].

[0033] [Fig.3] The [Fig.3] shows a view of an interface of the cleaning station of the [Fig.1] coupled to the envelope of the transport enclosure of the [Fig.2], one of the three clamping jaws of the interface (the one on the right in the figure) being uncapped.

[0034] [Fig.4] Fig.4 shows a flowchart of steps in a cleaning process.

[0035] [Fig. 5] Figure 5 shows a schematic view of an example of a water jet from a nozzle. hydraulics of the liquid water projection device carried by the robot head.

[0036] [Fig.6] Fig.6 shows a side view of the robot's head.

[0037] [Fig.7] [Fig.7] shows a view similar to [Fig.1] during the opening of the transport enclosure coupled to an internal loading port of said station.

[0038] [Fig.8] Fig.8 shows a schematic view of the cleaning station robot during the cleaning of the open transport enclosure envelope coupled to the internal loading port.

[0039] [Fig.9] [Fig.9] shows a view similar to [Fig.8] during the cleaning of a door of the transport enclosure.

[0040] [Fig. 10] [Fig. 10] shows a view similar to [Fig. 9] during the cleaning of the robot head.

[0041] [Fig. 11] [Fig. 11] shows a view similar to [Fig.7] during a purging step of the closed transport enclosure coupled to the internal loading port.

[0042] In these figures, identical or similar elements bear the same reference numbers.

[0043] Only the elements necessary for understanding the invention are represented. Detailed description

[0044] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features from different embodiments can also be combined or interchanged. to provide other achievements, without departing from the scope of the invention, as defined by the claims.

[0045] Fig. 1 represents an example of a cleaning station 1 of a transport enclosure 2 for the conveying and atmospheric storage of FOUP type semiconductor substrates for the English acronym Front Opening Unified Pod or FOSP for the English acronym Front Opening Shipping Box, the transport enclosure 2 allowing the conveying and atmospheric storage of semiconductor substrates.

[0046] These transport enclosures 2 are housings made of plastic material, such as polycarbonate, designed to contain 300mm semiconductor substrates, such as silicon wafers, in a controlled environment and to allow the transfer of these wafers between machines for processing or measurement purposes.

[0047] FOSB enclosures are used to convey wafers out of manufacturing facilities.

[0048] As more clearly seen in the example of [Fig. 2], a transport enclosure 2 for The conveying and atmospheric storage of FOUP or FOSP type semiconductor substrates includes a rigid envelope 3 (or shell) with a front opening 4. The front opening 4 is dimensioned to allow the introduction and extraction of the substrates.

[0049] The rigid enclosure 3 generally has at least two ventilation ports 5, between two and four, each ventilation port 5 having an opening provided in the bottom of the enclosure 3 fitted with a filter.

[0050] The transport enclosure 2 also includes internal shelves 6 for storing the wafers which can be molded as a single unit with the enclosure 3 ([Fig.2]) or fixed to the enclosure 3 with a gap between the two (so-called "double-walled" enclosures).

[0051] The envelope 3 may also have side handles 7 and a top handle 8 allowing its handling.

[0052] The transport enclosure 2 has a removable door 9 allowing the front opening 4 to be closed ([Fig.1]).

[0053] The cleaning station 1 allows the internal surfaces of the transport enclosure 2 to be cleaned.

[0054] The cleaning station 1 includes a cleaning chamber 10 receiving a robot 11 from the cleaning station 1 and an interface 12 configured to couple the envelope 3 of the transport enclosure 2 to the cleaning chamber 10.

[0055] The interface 12 includes an internal load port 13 (“internal load port” in English) capable of coupling to the rigid casing 3 of the transport enclosure 2 to position it opposite an opening of the cleaning chamber 10 of the station 1.

[0056] The interface 12 may include a sealing gasket surrounding the opening of the cleaning chamber 10 and configured to be interposed between the wall of the cleaning chamber 10 and a peripheral edge 15 of the casing 3. The sealing gasket is located beyond the contour of the door 9 so as to allow the door 9 to pass through. It is particularly rigid so as to meet semiconductor standards, i.e. not to produce particles and not to release volatile compounds in use.

[0057] The interface 12 may include at least one clamping jaw 16, for example three, for example one on each side of the opening of the cleaning chamber 10 and a third above it ([Fig. 3]). The clamping jaws 16 are configured to clamp the peripheral edge 15 of the casing 3 so as to compress the sealing gasket of the interface 12 and thus couple the casing 3 to the cleaning chamber 10 in a leak-proof manner.

[0058] According to one embodiment, each clamping jaw 16 comprises two respective linear actuators configured to drive a jaw in a respective direction, the directions of the two linear actuators being perpendicular to each other, one being intended to be parallel to a wall of the casing 3 of the transport enclosure 2. Thus, to couple the casing 3 to the transport enclosure 2, the jaw is successively brought close to a wall of the casing 3 perpendicular to that wall, then pushed against the peripheral edge 15 of the casing 3, parallel to the wall. And to uncouple the casing 3 from the transport enclosure 2, the jaw is successively moved away from the peripheral edge 15 parallel to the wall until it reaches a first stop of the clamping jaw 16, then moved away from the wall of the casing 3 perpendicular to that wall until it reaches a second stop of the clamping jaw 16.

[0059] This system ensures that the liquid water used for cleaning the transport enclosure 2 remains confined inside the cleaning chamber 10.

[0060] The cleaning station 1 further includes a door actuator 20 arranged in the cleaning chamber 10 ([Fig. 1]) and configured to open and close the transport enclosure 2 by moving the door 9 from the transport enclosure 2 into the cleaning chamber 10 away from or towards the front opening 4 to open it. The door actuator 20 is configured to move the door 9 sufficiently far from the casing 3 of the transport enclosure 2 so as not to re-wet the walls of the casing 3 during the door cleaning step. The door actuator 20 includes, for example, a linear actuator for moving the door 9 into the cleaning chamber 10 along a translation, for example, horizontally. According to an embodiment not shown, the door actuator 20 includes a linear actuator in the form of an arch under which the door 9 can be moved.

[0061] The door actuator 20 can further be configured to lock and unlock locking elements of the door 9. The locking elements, known per se, include, for example, latches carried by the door 9, actuated by radial or lateral sliding and engaging in the rigid casing 3 of the transport enclosure 2 when the transport enclosure 2 is closed. Once the locking elements are unlocked, the door actuator 20 reversibly secures the door 9. The door 9 can then be moved out of the front opening 4, for example, to the opposite side.

[0062] The cleaning station 1 may include a buffer chamber 21 adjacent to the cleaning chamber 10 and an external load port 22 for receiving a transport container 2, where the transport container 2 may be deposited by an operator or by an Overhead Hoist Transport (OHT) system from the manufacturing plant, i.e., a ceiling-mounted, automated, rail-guided system for loading and transporting the transport container 2. The external load port 22 may include a recognition sensor configured to identify the model of the transport container 2, in particular to ensure its compatibility with the cleaning station 1 receiving the transport container 2, and positioning pins to ensure the correct positioning of the transport container 2.

[0063] The buffer chamber 21 is interposed between the external loading port 22 and the cleaning chamber 10, the internal loading port 13 allowing the docking of the transport enclosure 2 to the cleaning chamber 10 being arranged in the buffer chamber 21 ([Fig.1]).

[0064] The buffer chamber 21 provides additional sealing around the transport enclosure 2, the interior of which is intended to be sprayed with water.

[0065] The external loading port 22 is configured to deposit the transport enclosure 2 onto the internal loading port 13 and to take the transport enclosure 2 from the internal loading port 13. For this purpose, the external loading port 22 may have a fork that fits between positioning pins of the internal loading port 13.

[0066] The robot 11 arranged in the cleaning chamber 10 comprises an articulated arm 23 and a head 24 arranged at the end of the articulated arm 23. The articulated arm 23 has six axes (or six joints), here six pivots. According to one embodiment, the articulated arm 23 has successive first, second, third, fourth, fifth, and sixth axes XI, X2, X3, X4, X5, X6 between a base 25 of the articulated arm 23 and the head 24. The first axis XI is vertical, the second and third axes X2, X3 are horizontal, the fourth axis X4 allows the end of the arm (carrying the fifth and sixth axes X5, X6) to pivot on itself, and the fifth axis X5 allows breaking the wrist of the arm (carrying the sixth axis X6) and the sixth axis X6 is a rotation axis at the end of the wrist, perpendicular to the fifth axis X5.

[0067] The articulated arm 23 is programmable. It can move precisely, allowing it to follow the specific shape of the inside of the transport container 2's casing. Furthermore, it can move quickly, reducing the processing time per transport container 2. It can also move repeatably, thus providing better control of the cleaning process. The distance between the head 24 and the casing 3 is controlled, enabling reproducible cleaning of the container 2 from one transport container 2 to the next.

[0068] As can be seen in [Fig.6], the head 24 of the robot 11 carries a gas projection device 26 configured to project (blow) a jet of pressurized gas.

[0069] In addition, the cleaning station 1 includes a liquid water spraying device 27 configured to wet the internal walls of the envelope 3 of the transport enclosure 2 with a predetermined quantity of liquid water less than 200ml / m2, such as less than 100ml / m2.

[0070] Once coupled to the external loading port 22, the closed transport enclosure 2 can be moved into the buffer chamber 21, conveyed in horizontal translation through the external loading port 22 to the internal loading port 13 of the cleaning chamber 10 where the transport enclosure 2 can be deposited.

[0071] Alternatively, the transport container 2 can be conveyed to a storage area of ​​the buffer chamber 21 where it can be stored under a laminar flow of clean gas while awaiting cleaning. For this purpose, the buffer chamber 21 may include a moving device 28 configured to grasp the transport container 2, for example by its upper handle 8, and move it, for example from the external loading port 22, to a storage shelf 29 in the buffer chamber 21, for example located at a higher level. The moving device 28 is also configured to grasp the transport container 2 and move it away from the storage shelf 29, towards the external loading port 22.

[0072] Then, when the external loading port 22 has placed the transport enclosure 2 onto the positioning pins of the internal loading port 13, the latter can couple the transport enclosure 2 in a hermetic manner to the cleaning chamber 10 via the clamping jaws 16 so that the transport enclosure 2 can be opened by the door actuator 20.

[0073] Once the transport enclosure 2 is opened, i.e., the door 9 has been moved away from the front opening 4 of the enclosure 3, a presence sensor 18, such as a An optical sensor, such as an optical fiber, can verify that envelope 3 is properly emptied of its substrates and / or does not contain debris.

[0074] According to an example of an embodiment illustrated in [Fig.6], the presence sensor 18 is carried by the head 24 of the robot 11. The cable or optical fiber 19 of the presence sensor 18 can extend along the articulated arm 23 to be connected to a power supply and / or a data processing system.

[0075] Then the envelope 3 and the door 9, if applicable, can be cleaned with liquid water according to the cleaning process 100 comprising the succession of steps described below and illustrated in [Fig.4].

[0076] First mooring stage 101:

[0077] In a first wetting step 101, the internal walls of the casing 3 of the transport enclosure 2 are wetted by means of the liquid water spraying device 27, with a predetermined quantity of liquid water less than 200ml / m2, such as less than 100ml / m2. In the case of a transport enclosure 2 designed to contain 300mm semiconductor substrates, the surface area of ​​the internal walls of the casing 3 is less than 0.5m2, and consequently, the quantity of liquid water consumed for wetting is less than 100ml, in particular less than 50ml, which is very little.

[0078] The liquid water is deionized; it can be pure or ultrapure or contain additives.

[0079] All internal walls of the casing 3 accessible by the liquid water spraying device 27 can be wetted.

[0080] Liquid water can be projected as a mist or spray. The water is atomized into fine droplets smaller than 200 µm, with a size between 50 µm and 200 µm, such as 100 µm on average. The liquid water can be projected by a nebulizer (or mist sprayer or atomizer or vaporizer) from the cleaning chamber 10. Liquid water projected as a mist is easier and faster to remove by the subsequent dewetting step 102.

[0081] The liquid water projection device 27 can be moved by an actuator to be mobile independently of the robot 11, linear and / or rotary, in particular to be moved inside the envelope 3 of the transport enclosure 2 in order to project the liquid water into the envelope 3 of the transport enclosure 2.

[0082] According to an example of an embodiment illustrated in [Fig.6], liquid water is projected into the envelope 3 of the transport enclosure 2 by a liquid water projection device 27 carried by the head 24 of the robot 11.

[0083] The speed of movement of the liquid water projection device 27 carried by the head 24 of the robot 11 on straight trajectories is for example between 50mm / s and 150mm / s, such as 100mm / s.

[0084] According to one embodiment, the liquid water projection device 27 comprises at least one hydraulic nozzle carried by the head 24 of the robot 11, for example two or three hydraulic nozzles.

[0085] The hydraulic nozzles are connected to a liquid water supply system, for example via a common hydraulic pipe 32 extending along the articulated arm 23.

[0086] Hydraulic nozzles are, for example, hollow cone nozzles. This type of nozzle forms a hollow cone-shaped jet of water projecting a circle of liquid onto surfaces ([Fig.5]), which limits the amount of water used and allows for the formation of very fine water droplets.

[0087] The diameter of the outlet orifices of the hydraulic nozzles is for example less than 1000pm, such as 400pm, in particular with an upstream pressure between 3105 Pa and 5105 Pa and a flow rate between 20ml / min and 30ml / min.

[0088] The nozzle structure, orifice size and upstream water pressure allow the liquid water to be projected in the form of a mist of fine droplets.

[0089] According to one embodiment, the liquid water projection device 27 comprises two hydraulic nozzles whose respective orifice directions are separated by an angle between 50° and 70°, such as 60°. The hydraulic nozzles can thus wet a larger wall surface in a single pass of the articulated arm 23 while allowing the robot 11 to move within the transport enclosure 2, these movements being limited by the dimensions of the front opening 4 of the casing 3.

[0090] The head 24 of the robot 11 then carries both the liquid water spraying device 27 and the gas spraying device 26, which allows for great flexibility in the distribution of liquid water and in the subsequent gas spraying within the envelope 3, as will be seen below. The liquid water spraying device 27 and the gas spraying device 26 are, however, separate, each having its own fluid inlet.

[0091] Second successive dewetting step 102 by projection of a jet of gas pressurized:

[0092] In a second successive dewetting step 102 by projection of a pressurized gas jet, the piloting of the articulated arm 23 is controlled to move the gas projection device 26 in the envelope 3 along a trajectory and an orientation of the gas jet allowing the pressurized gas jet to carry the liquid deposited on the internal walls out of the envelope 3.

[0093] In particular, the trajectory of the gas jet includes displacements from the bottom of the casing 3 towards the front opening 4. The orientation of the gas jet is not axial. It differs from the normal to the surface of the wall, distinct from a jet along the axis of the sixth axis X6 of the articulated arm 23, the gas jet having an inclination relative to the wall so as not to disperse the water droplets but to direct them towards the front opening 4.

[0094] This second dewetting step 102 by projection of a pressurized gas jet makes it possible to remove the liquid from the surfaces wetted during the previous wetting step 101, but also to wet the walls that are difficult to access, by pushing the liquid present on the dry walls by the gas jet, these walls not having been able to be wetted directly by the liquid water projection device 27.

[0095] According to one embodiment, the gas projection device 26 comprises at least one flat jet blow nozzle configured to produce a gas blade. The gas blade facilitates the entrainment of the liquid by sweeping over the surfaces.

[0096] The flat jet blow nozzle can be formed by a slot or by a plurality of aligned orifices. The gas projection device 26 comprises, for example, a single flat jet blow nozzle or two flat jet blow nozzles placed side by side and arranged so that the flat jets of the nozzles are aligned.

[0097] The width of the slot or aligned orifices of the gas projection device 26 is, for example, between 40 mm and 150 mm, for example 100 mm. This dimension is relatively wide to allow sweeping a large area of ​​the walls and small enough to allow the gas projection device 26 to enter and be moved within the envelope 3 of the transport enclosure 2 with sufficient maneuverability for the articulated arm 23.

[0098] According to an example of an embodiment visible in [Fig.6], the angle formed between the plane of the flat jet of at least one flat jet blow nozzle and the axis of rotation at the end of the articulated arm 23 (the sixth axis X6) is distinct from a zero angle, such as between 30° and 60°, such as 45°.

[0099] This specific angle allows the gas blade of the flat jet blow nozzles to be oriented at a re-entrant angle at the end of the articulated arm 23. This re-entrant angle acts like a pre-positioned "shovel" to scrape water droplets, that is, to draw them from the bottom of the transport enclosure 2 outwards. This re-entrant angle also allows the articulated arm 23 to access certain hard-to-reach areas, such as the rear of internal shelves 6 or diffusers of certain transport enclosures 2, by pre-orienting the flat jet at a re-entrant angle. Furthermore, this shape facilitates blowing outwards from the contours of the front opening 4 of the casing 3 without pushing the droplets back into the casing 3.

[0100] The flat jet blow nozzles are respectively connected to a gas supply system, for example via a respective gas pipe 35 extending along the articulated arm 23. There is, for example, one gas pipe 35 per nozzle to obtain a sufficiently powerful blowing flow, in particular to allow the entrainment of water droplets in hard-to-reach areas.

[0101] The total gas flow rate is, for example, between 400 l / min and 1200 l / min in total, i.e., between 200 l / min and 600 l / min per nozzle for a gas spraying device 26 comprising two nozzles. This flow rate makes it possible to produce a focused and powerful gas jet, enabling the drying and entrainment of droplets on the plastic surfaces.

[0102] The speed of movement of the gas projection device 26 along straight trajectories is, for example, between 150 mm / s and 250 mm / s, such as 200 mm / s. The gas projection device 26 thus moves quickly enough to meet production requirements and slowly enough to allow the entrainment of water droplets.

[0103] The gas is preferably neutral and dry, for example nitrogen or clean dry air (CDA). The gas projection device 26 may also be equipped with particle filters.

[0104] The cleaning process 100 thus comprises two distinct and successive steps for cleaning the internal walls of the transport enclosure 2 with liquid water which, because it is projected in very small quantities, can be expelled from the casing 3 by entrainment of the pressurized gas jet while being sufficient for the contaminants to be solubilized in the water film. The droplets react, dissolve, and transport the particles and soluble chemical species, in particular acids, which are then rapidly dried or carried out of the casing 3 of the transport enclosure 2. In other words, spraying a larger quantity of water on the internal walls of the enclosure 2 does not clean them better. On the contrary, projecting more water slows down the drying process and increases water consumption, which is hardly acceptable in production and is undesirable from an ecological and economic point of view.With the cleaning process 100 according to the invention, water consumption is significantly reduced compared to the amount of water used in prior art devices, in particular by a factor of one hundred. This small amount of projected water allows for rapid dewlogging of the walls by entrainment of the water film by a pressurized gas jet moved by means of the articulated arm 23 of the robot 11. Dewlogging by projection of a well-oriented pressurized gas jet allows the casing 3 of the transport container 2 to dry by entrainment, with little or no water evaporation. Indeed, the contaminating species trapped by the water droplets, in particular the . Acids can remain in place during drying by water evaporation, including by infrared radiation. In contrast, dew removal is a mechanical removal of water, achieved by entrainment with pressurized gas. This action allows the entire process, including droplets and contaminants, to be evacuated from enclosure 2, preventing contaminants from remaining on the walls after evaporation and also saving time, as evaporation is relatively slow. This is made possible by the use of the six-axis robotic arm 23. Its maneuverability and speed allow the gas projection device 26 to be inserted into enclosure 3 and moved along an optimized trajectory to push the liquids and impurities out of enclosure 3 by entrainment against the internal walls of enclosure 2 without drying them in place.

[0105] Furthermore, when the gas projection device 26 is carried by the head 24 of the robot 11, the dewetting of the walls by gas sweeping by the articulated arm 23 is more efficient than natural drying because more areas are accessible to the gas jet blown by the gas projection device 26 without needing to put the transport enclosure 2 under vacuum, which reduces the cost and size of the station 1.

[0106] Door cleaning step 103:

[0107] These two successive steps of wetting and dewetting can be repeated for cleaning the inner wall of the door 9 of the transport enclosure 2.

[0108] For this purpose, the cleaning process 100 includes a door cleaning step 103 comprising a first wetting step during which the internal wall of the door 9 of the transport enclosure 2 is wetted with a predetermined quantity of liquid water less than 200ml / m2, such as less than 100ml / m2, and a second successive dewetting step by projection of a pressurized gas jet during which the articulated arm 23 is controlled to move the gas projection device 26 in relation to the door 9 along a trajectory and orientation of the gas jet so that the pressurized gas jet carries the liquid deposited on the internal walls out of the door 9.

[0109] The same means for wetting and dewetting the casing 3 of the transport enclosure 2 can be used for cleaning the door 9. In particular, as in the first wetting step 101, liquid water can be projected as a mist by a liquid water projection device 27, for example, carried by the head 24 of the robot 11, such as at least one hydraulic nozzle. Also, as in the subsequent second dewetting step 102 by projection of a pressurized gas jet, the gas can be projected by at least one flat jet blow nozzle configured to produce a gas blade.

[0110] In the case of a transport enclosure 2 designed to contain 300mm semiconductor substrates, the surface area of ​​the internal wall of the door 9 is less than 0.1m2, and consequently, the amount of liquid water consumed for wetting is less than 20ml, in particular less than 10ml, which is very little.

[0111] The cleaning station 1 may include a gas spray nozzle 36 arranged in the cleaning chamber 10, enabling the cleaning of the head 24 of the robot 11 ([Fig. 1]). The gas spray nozzle 36 includes, for example, one or more blow-out orifices in the shape of an arc, ring or frame through which the articulated arm 23 of the robot 11 can penetrate to clean the head 24 by blowing gas and thus the gas projection device 26, and where applicable the liquid water projection device 27 ([Fig. 10]).

[0112] The actual cleaning step, comprising the wetting step 101 and the dewetting step 102 of the envelope 3 and the door cleaning step 103 (wetting and dewetting of the door 9), between the time when the door 9 is opened and the time when it is closed, consumes less than 200ml / m2, such as less than 100ml / m2.

[0113] In the case of a transport enclosure 2 designed to contain 300 mm semiconductor substrates, the surface area of ​​the internal walls of the transport enclosure 2 (shell 3 and door 7) is less than 0.6 m², and consequently the amount of liquid water consumed for wetting is less than 120 ml, in particular less than 60 ml, which is very little. The duration of the cleaning step of the transport enclosure 2 coupled to the internal loading port 13 can be less than or equal to three and a half minutes, which is very fast.

[0114] Purge step 104:

[0115] The cleaning process 100 may include a successive purging step 104 during which the closed transport container 2 is purged with a dry purging gas, such as nitrogen. This gas may be heated.

[0116] This purging step 104 is carried out after cleaning the transport enclosure 2 and reduces humidity. This purging step 104 can last one minute.

[0117] For this purpose, the buffer chamber 21 may include a purge device 37 ([Fig. 1]) comprising, for example, movable nozzles and an actuator for moving the nozzles to introduce or connect them to the ventilation ports 5 located under the lower face of the shell 3 of the transport enclosure 2. The nozzles of the purge device 37 allow a flow of dry purge gas, such as nitrogen, to be delivered into the closed transport enclosure 2 via the ventilation ports 5. Part of the gas flow exits through the ventilation ports 5 and can be analyzed by a humidity sensor.

[0118] The cleaning station 1 further comprises a control unit 40, comprising one or more controllers or a computer, configured to implement the cleaning process 100, in particular to control the piloting of the articulated arm 23 in order to move the head 24 of the robot 11 in the envelope 3 in the first wetting step 101 where applicable, in the second dewetting step 102 and during the subsequent door cleaning step 103 where applicable.

[0119] We will now describe an example of a cleaning process 100 implemented in a cleaning station 1 with reference to Figures 1, 4 and 7 to 11.

[0120] An operator or a robot places a transport enclosure 2 on a platform of the external loading port 22, which positions and controls the model of the transport enclosure 2 ([Fig. 1]). Then, the external loading port 22 raises the transport enclosure 2 above positioning pins and moves the coupled and closed transport enclosure 2 in the buffer chamber 21 to the internal loading port 13 of the cleaning chamber 10 or to a storage area of ​​the buffer chamber 21.

[0121] Then, the external loading port 22 deposits the transport container 2 onto the internal loading port 13 of the cleaning chamber 10, this container 2 possibly having been retrieved from the laminar flow storage area after a cleaned transport container 2 has been removed from the cleaning chamber 10, if applicable. Two transport containers 2 can thus cross paths in the buffer chamber 21.

[0122] The internal loading port 13 advances and couples the transport enclosure 2 in a sealed manner to an opening in the cleaning chamber 10 via the clamping jaws 16. The external loading port 22 can return to the initial position.

[0123] The door actuator 20 of the cleaning chamber 10 unlocks the door 9 of the transport enclosure 2 and opens it by moving the door 9 away from the envelope 3. At this moment, the articulated arm 23 of the robot 11 is in the folded position to allow passage for the door actuator 20 and the door 9 ([Fig.7]).

[0124] Next, the enclosure 3 of the transport container 2 is cleaned ([Fig. 8]).

[0125] In a first wetting step 101, the internal walls of The envelope 3 of the transport enclosure 2 is wetted with a predetermined quantity of liquid water less than 200 ml / m², such as less than 100 ml / m². The liquid water is sprayed into the envelope 3 of the transport enclosure 2 by the liquid water spraying device 27, for example, mounted on the head 24 of the robot 11, for example, by hydraulic nozzles and, for example, in the form of a mist. During this wetting step 101, all internal walls accessible by the liquid water spraying device 27 are wetted. However, the exterior of the envelope 3 of the transport enclosure 2 is not wetted. Since the envelope 3 is sealed to the cleaning chamber 10, the liquid water used for cleaning the transport enclosure 2 remains confined within the cleaning chamber 10. The chamber Buffer 21 ensures additional sealing between the transport enclosure 2 and the cleanroom of the manufacturing plant. Water can be collected and discharged from station 1 via a retention basin.

[0126] Following the dewetting step 101, in this embodiment, the liquid water supply is shut off in the hydraulic line 32 of the liquid water supply system for the hydraulic nozzles, and gas is sent to the gas lines 35 of the gas supply system for the flat jet blow nozzles. The changeover between the wetting step 101 and the dewetting step 102 can therefore be very quick, as there is no need to change nozzles or purge the lines.

[0127] In the second successive dewetting step 102, the piloting of the articulated arm 23 is controlled to move the gas projection device 26 in the envelope 3 along a trajectory and an orientation of the gas jet allowing the pressurized gas jet to carry the liquid deposited on the internal walls out of the envelope 3.

[0128] Then, we can proceed to clean the door 9 of the transport enclosure 2 ([Fig.9]).

[0129] For this purpose, the articulated arm 23 of the robot 11 can turn around facing the door 9 and carry out a first wetting step during which the inner wall of the door 9 of the transport enclosure 2 is wetted with a predetermined quantity of liquid water less than 200ml / m2, such as less than 100ml / m2 and a second successive dewetting step by projection of a pressurized gas jet during which the piloting of the articulated arm 23 is controlled to move the gas projection device 26 in relation to the door 9 along a trajectory and an orientation of the gas jet so that the pressurized gas jet carries the liquid deposited on the inner wall out of the door 9.

[0130] It is also possible to reverse these steps and clean the door 9 before cleaning the envelope 3 of the transport enclosure 2.

[0131] The articulated arm 23 of the robot 11 can plunge into the ring of the gas shower 36 to clean the head 24 by blowing gas, for example at the end of each wetting step of the envelope 3 or of the door 9, before each dewetting step.

[0132] After the transport enclosure 2 has been cleaned, the door actuator 20 closes and locks the enclosure 2, which is still coupled to the internal loading port 13 in the buffer chamber 21.

[0133] In a subsequent purging step 104, the closed transport container 2 is purged with a dry purge gas. For this purpose, the movable nozzles of the purging device 37 are inserted into, or connected to, the ventilation ports 5 of the shell 3 of the transport container 2 ([Fig. 11]). The nozzles of the purging device 37 deliver a flow of dry purge gas into the closed transport container 2 via the ventilation ports 5. A Part of the gas flow exits through ventilation ports 5 and can be analyzed by a humidity sensor.

[0134] Then the transport enclosure 2 is repositioned on the external loading port 22 ([Fig.l]).

[0135] The total cleaning time per transport enclosure 2 from berthing on the external loading port 22 until return to the external loading port 22 and considering that there is no waiting in the storage area of ​​the buffer chamber 21, may be less than or equal to five minutes.

Claims

Demands

1. A cleaning method (100) for a transport container (2) for the conveying and atmospheric storage of semiconductor substrates in a cleaning station (1), said transport container (2) comprising a casing (3) having a front opening (4) and a removable door (9) for closing the front opening (4), the cleaning station (1) comprising a robot (11) having a six-axis articulated arm (23) and a head (24) arranged at one end of the articulated arm (23), said head (24) carrying a gas projection device (26) configured to project a pressurized gas jet, characterized in that, once the transport container (2) is opened, the cleaning method (100) comprises the following sequence of steps: - a first wetting step (101) during which the internal walls of the casing (3) of the transport container (2) are wetted with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.0001m3 / m2), - a second successive dewetting step (102) by projection of a pressurized gas jet, during which the piloting of the articulated arm (23) is controlled to move the gas projection device (26) in the envelope (3) along a trajectory and an orientation of the gas jet allowing the pressurized gas jet to carry the liquid deposited on the internal walls out of the envelope (3).

2. Cleaning method (100) according to claim 1, characterized in that in the first wetting step (101), the liquid water is projected in the form of a mist, in particular in droplets of dimensions less than 200pm.

3. Cleaning method (100) according to any one of the preceding claims, characterized in that in the first wetting step (101), liquid water is projected by a liquid water projection device (27) carried by the head (24) of the robot (11).

4. Cleaning method (100) according to any one of the preceding claims, characterized in that it comprises a successive third purging step (104) during which the closed transport vessel (2) is purged by a dry purging gas.

5. A cleaning method (100) according to any one of the preceding claims, characterized in that it comprises a door cleaning step (103) comprising: - a first wetting step during which the inner wall of a door (9) of the transport enclosure (2) is wetted with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.000 lm3 / m2), - a second successive dewetting step by projection of a pressurized gas jet during which the articulated arm (23) is controlled to move the gas projection device (26) in relation to the door (9) along a trajectory and orientation of the gas jet so that the pressurized gas jet carries the liquid deposited on the inner wall out of the door (9).

6. Cleaning station (1) of a transport enclosure (2) for the conveying and atmospheric storage of semiconductor substrates, characterized in that the cleaning station (1) comprises: - a robot (11) having a six-axis articulated arm (23) and a head (24) at one end of the articulated arm (23), said head (24) carrying a gas projection device (26) configured to project a pressurized gas jet, - a cleaning chamber (10) receiving the robot (11) and having an interface (12) configured to couple an enclosure (3) of the transport enclosure (2) to the cleaning chamber (10), - a door actuator (20) arranged in the cleaning chamber (10) configured to open and close the transport enclosure (2) by moving a door (9) of the transport enclosure (2) away from or towards a front opening (4) of the enclosure (3),- a liquid water projection device (27) configured to wet the internal walls of the casing (3) of the transport enclosure (2) with a predetermined quantity of liquid water less than 200ml / m2 (0.0002m3 / m2), such as less than 100ml / m2 (0.0001m3 / m2), and - a control unit (40) configured to implement a cleaning process (100) according to one of the preceding claims, in particular to control the piloting of the articulated arm, (23) in order to move the head (24) of the robot (11) into the envelope (3) in the second dewetting step (102).

7. Cleaning station (1) according to the preceding claim, characterized in that the liquid water projection device (27) comprises at least one hydraulic nozzle, such as a hollow cone nozzle, carried by the head (24) of the robot (11), for example two or three hydraulic nozzles.

8. Cleaning station (1) according to any one of claims 6 or 7, characterized in that the gas projection device (26) comprises at least one flat jet blow nozzle configured to produce a gas blade.

9. Cleaning station (1) according to the preceding claim, characterized in that the angle (a) formed between the plane of the flat jet of at least one flat jet blow nozzle and the axis of rotation (X6) of the end of the articulated arm (23) is distinct from a zero angle, such as being between 30° and 60°.

10. Cleaning station (1) according to any one of claims 6 to 9, characterized in that it comprises a buffer chamber (21) adjoining the cleaning chamber (10) and an external loading port (22) for receiving a transport enclosure (2), the buffer chamber (21) being interposed between the external loading port (22) and the cleaning chamber (10), the interface (12) comprising an internal loading port (13) capable of coupling to the rigid casing (3) of the transport enclosure (2) to position it opposite an opening in the cleaning chamber (10), the external loading port (22) being configured to deposit the transport enclosure (2) onto the internal loading port (13) and to take the transport enclosure (2) from the internal loading port (13), the internal loading port (13) being arranged in the buffer chamber (21).

11. Cleaning station (1) according to the preceding claim, characterized in that the buffer chamber (21) includes a purging device (37) comprising movable nozzles and an actuator enabling the nozzles to be moved to be introduced or connected to ventilation ports (5) of the transport enclosure (2) located under the lower face of the casing (3).

12. Cleaning station (1) according to any one of claims 10 or 11, characterized in that the buffer chamber (21) comprises a displacement device (28) configured to grasp the transport enclosure (2) to move it towards or away from a storage shelf (29) of the buffer chamber (21).

13. Cleaning station (1) according to any one of claims 6 to 12, characterized in that the interface (12) comprises a sealing gasket arranged around the opening of the cleaning chamber (10) and at least one clamping jaw (16) configured to hermetically couple the casing (3) to the cleaning chamber (10) by compressing the sealing gasket.

14. Cleaning station (1) according to the preceding claim, characterized in that at least one clamping jaw (16) comprises two linear actuators configured to drive a jaw in a respective direction, the directions of the two linear actuators being perpendicular to each other, one being intended to be parallel to a wall of the casing (3) of the transport enclosure (2).

15. Cleaning station (1) according to any one of claims 6 to 14, characterized in that it comprises a gas shower (36) arranged in the cleaning chamber (10) having one or more blow holes in the form of an arc, ring or frame and through which the articulated arm (23) of the robot (11) can plunge to clean the head (24) by blowing gas.

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