WO2004021408A1 - Device and method for treating substrates - Google Patents

Abstract

The invention relates to a device and method for treating substrates, which renders a good and uniform treatment during high throughput possible. According to the invention, the device is configured for simultaneously treating individual substrates. This device comprises a multitude of essentially identical process units, which are arranged one above the other and which each have a substrate holder for accommodating an individual substrate, and comprises a handling device with a number of substrate holders that corresponds to the number of process units in order to simultaneously load and unload a multitude of substrates into or from process units. In addition, the aim of the invention is to provide a device for conveying substrates that makes it possible to simultaneously load a multitude of process units. To this end, the invention provides a device that comprises a large number of parallelly arranged substrate holders that corresponds to the number of substrates to be conveyed and comprises a device for altering the distance between the substrate holders. The distance can be altered, in essence, between a first distance, which corresponds to the distance of the substrates in a first unit, and a second distance, which corresponds to the distance between second units.

Description

 Device and method for treating substrates

The present invention relates to an apparatus and a method for treating substrates, and in particular for treating substrates in semiconductor production. The invention relates in particular to the wet-chemical cleaning of substrates.

Two types of device for wet chemical treatment of substrates are known in the semiconductor industry. In one of these plants, the substrates are treated in packages, so-called lots or trays, as described, for example, in DE-A 100 17 010, which goes back to the same applicant. In an alternative device, the substrates are each treated individually, as is known, for example, from DE 101 22 669, which has not been published by the same applicant.

The treatment of the substrates can include, for example, immersion in cleaning media or rinsing liquids or spraying treatment fluid. A process usually consists of a sequence of cleaning and rinsing steps followed by substrate drying. Both types of treatment, i.e. the tray process or the single disc process are used independently of each other depending on the desired application. The treatment fluids used are used both in a single application with subsequent discharge or in reuse in recirculation / filtration systems.

The above-mentioned tray processes and the single-wafer processes cannot ideally meet the requirements, for example in semiconductor chip production, in terms of cleaning quality and productivity. Tray processes offer high productivity due to the simultaneous treatment of several substrates and also offer advantages in the use of chemicals, especially when reused. When developing ever smaller structures to be cleaned on the substrates, however, there are limits with regard to the cleaning effectiveness achieved. In the tray processes, the process media cannot act directly and evenly on the individual substrate surfaces, since the trays are usually gradually immersed in a treatment fluid. In addition, temperature or flow irregularities across the horde can lead to unacceptable variations in process results. Another disadvantage of the tray processes, in which the trays are completely immersed in a treatment fluid, is the very high consumption of a rinsing medium, usually deionized water (di-water) and the space requirement of these systems.

With single-wafer processes, an improved uniformity of the process results can be achieved, among other things by the possibility of direct action on each individual substrate. This means that future process requirements can also be better met. Single slice processes, however, have a low throughput rate, which leads to poor productivity. The reason for this can be, for example, the long process times of individual treatment steps, such as certain cleaning steps, which can take up to one hour.

From US-A-5, 788,447, for example, a device for treating semiconductor wafers is known, in which a plurality of process chambers arranged vertically one above the other are provided, in which two wafers are treated simultaneously. The process chambers, which are arranged vertically one above the other, face a large number of loading locks and are separated from the loading locks via a vacuum transport space. A

Handling device in the vacuum transport space in each case transports two of the wafers between a loading lock and a process chamber, the process chambers being loaded individually and sequentially. The loading lock is loaded via an external handling device, which removes a total of five wafers from one wafer cassette and into one

Received in the loadlock. During the transport of the wafers, the distance between them is changed using a screw shaft. Based on the known devices and methods, the present invention is therefore based on the object of providing a device or a method for treating substrates which enables a good and uniform treatment with high throughput. Furthermore, the present invention is based on the object of providing a device for transporting substrates which enables the simultaneous loading of a multiplicity of process units.

According to the invention, this object is achieved in a device for treating substrates, in particular in the manufacture of semiconductors, in that a multiplicity of essentially identical process units arranged one above the other, each having a substrate receptacle for receiving an individual substrate, and a handling device with one of the number the number of substrate receptacles corresponding to the process units is provided for simultaneous loading and unloading of a large number of substrates in or out of the process units. The device according to the invention enables simultaneous loading and unloading of a large number of process units and thus simultaneous individual processing of a large number of substrates. The large number of process units enables direct action on the individual substrates, which enables uniform process success across the individual substrates and the large number of substrates. On the other hand, the throughput of the device is increased by the simultaneous processing of a large number of substrates. The present invention thus provides the advantages of both a tray process (high throughput) and an individual process (uniform treatment results). The stacking of the process units enables a small footprint of the device, which is usually arranged in clean rooms in which the footprint should be reduced due to the associated costs. In addition to the large number of process units, the handling device, which has a number of substrate receptacles corresponding to the number of process units, is also of particular importance in order to enable simultaneous loading and unloading of the process units. According to a particularly preferred embodiment of the invention, a spreading mechanism is provided for vertically moving the substrates in order to change the distance between the substrates. This spreading mechanism enables the removal of the substrates from conventional substrate holding cassettes, which as a rule keep the substrates so closely spaced that a single treatment of the substrates is not possible, and the subsequent spreading of the substrates in such a way that they are in the individual process units can be included. The individual process units can each be spaced so far apart that individual treatment of the substrates is possible.

In one embodiment of the invention, the process units are arranged in a common housing with a common process chamber. The common housing preferably has a common opening for loading and unloading substrates, the opening having a height which is smaller than the distance between an uppermost and a lowermost one of the process units arranged one above the other in their treatment positions. The common opening facilitates control of the device since the handling device is aligned with only one opening and only one opening has to be opened and closed. Providing a small opening, which is smaller than the distance between an uppermost and a lowermost one of the process units arranged one above the other in their treatment positions, results in a simplified sealing from the environment and furthermore the risk that contaminants enter the housing or process media emerge from the housing, reduced. For a simple construction of the device, the opening is arranged essentially centrally along the height of the housing.

In order to enable the substrates to be transported within the housing, a movement unit with a spreading mechanism for vertically moving substrate receptacles of the process units between a receiving position and a treatment position in the housing is preferred intended. The movement unit with the spreading mechanism enables the substrates to be loaded into the housing at a relatively short distance and then to be brought to the distance required for the individual treatment.

In an alternative embodiment of the invention, the process units are each arranged in their own process chamber, each of which has its own opening for loading and unloading the substrates. Providing the process units in their own process chambers prevents the risk of media spreading between the different process units. Even if all process units arranged in a common chamber run the same processes at the same time, running down a process medium from an overhead process unit to an underlying process unit can lead to a change in the process result of the underlying process unit, since more process medium is now available there than is provided by the respective process unit.

In order to enable the substrates to be at the required distance to load the movable substrate holder of the process units or the individual process chambers, the handling device preferably has a spreading mechanism for moving the substrates vertically relative to one another. The lifting height can be chosen to be low if the handling device is connected in combination with the spreading mechanism provided in the common housing, since two-part spreading is possible here until the substrates reach the distance required for the individual treatment. When loading the process units, which are arranged in their own process chambers, spreading within the process chamber housing is not possible or only to a limited extent, and therefore a larger lifting height must be selected.

For a simple design of the expanding mechanism, it has at least one telescopic arrangement which, for example, is pneumatic or hydraulic. can be drastically retracted and extended. The telescopic arrangement can be operated essentially without mechanical friction, as a result of which contamination by the spreading mechanism is avoided. In addition, a telescope arrangement can be easily constructed and it ensures predetermined distances before and after spreading in a simple manner, for example by appropriate end stops of the individual telescope elements. In order to provide stable guidance of the substrates during the spreading movement, a vertical guide member with a number of substrate receptacles corresponding to the number of process units is preferably provided. The vertical guide member provides a secure and stable guidance of the substrate receptacles and the substrates placed thereon, so that a movement unit such as a telescopic arrangement, which can also be extended and retracted pneumatically or hydraulically, for example, can be designed relatively simply. This is made possible because the vertical guide element ensures lateral stability and essentially absorbs the forces acting on the expansion mechanism.

For a good connection to existing upstream and / or downstream process modules, the substrate receptacles of the expansion mechanism are in a non-expanded position, preferably in a vertical central region of the guide member. In this case, one of the substrate receptacles is preferably attached to the guide member in a stationary manner, while the others are movable along the guide member. This simplifies the structure for the movement unit for moving the substrate receptacles. In order to keep the required lifting height of substrate receptacles of the expansion mechanism between an initial position and an end position as low as possible, the substrates can be moved at least partially in different vertical directions. As a result, the maximum required lifting height of the expansion mechanism in a vertical direction can be considerably reduced, as a result of which less demands are placed on the movement mechanism. For a simple structure and simple control of the device, the substrate receptacles and / or the guide member preferably have stops for limiting the vertical movement of the substrate receptacles. In one embodiment of the invention, a movement unit is provided for laterally moving the guide member in order to enable simultaneous loading and unloading of the process units from the substrate receptacles of the guide member in a simple and inexpensive manner.

In a preferred embodiment of the invention, the handling device has a movement unit for transporting the substrates between a substrate receiving cassette and the process units or the substrate receptacles of the guide member. The handling device thus enables the direct loading and unloading of the process units from a substrate receiving cassette or the loading by means of a movement unit in a simple and inexpensive manner in combination with a spreading mechanism which has a vertical guide member with substrate receptacles. Direct loading is preferred if only a slight spreading of the substrates is required, such as in the exemplary embodiment in which a spreading mechanism is provided within a common process chamber. The combination of movement unit and spreading mechanism with guide member is preferred when a large spreading of the substrates is necessary, such as when loading process units, which are each arranged in a separate process chamber.

In order to enable the process units to be controlled as simultaneously as possible and to reduce the number of supply components, at least one common media supply is preferably provided for the process units. This makes it possible to achieve a compact design and also to ensure that the respective process units are treated uniformly, since the process medium comes from a common source. A rotatable substrate holder is preferably provided for homogenizing the treatment results within each individual process unit. The process units preferably each have a multiplicity of feed lines for process media in order to enable different processes and to avoid media carryover within the respective processes, which could occur with a common feed line. The process units preferably have a drying unit in order to enable drying of the substrates, in particular after a wet chemical treatment. Drying is particularly necessary to prevent media transfer from the process units and to prevent liquid from drying on the substrates. To improve the respective processes, each process unit preferably has an ultrasound or megasound unit. For good insulation of the process units from the environment, at least one device for opening and closing the common opening of the common housing or the individual openings of the separate process chambers is preferably provided.

In a further preferred embodiment of the invention, the plurality of process units arranged one above the other forms a first group of process units, and adjacent to the first group at least a second group of essentially identical process units arranged one above the other is provided, at least parts of the handling device of the first group being such are movable that they can also be used for loading and unloading the second group. As a result, the throughput of the device can be increased further in a simple and inexpensive manner, the same handling device being able to be used at least in part in order to reduce the number of components required. Depending on the relationship between the required loading and unloading time in relation to the respective treatment time in the group of process units, the entire handling device can be used for loading and unloading several groups or only partial areas thereof. The object on which the invention is based is also achieved in a method for treating substrates, in particular in the manufacture of semiconductors, the method involving simultaneous removal of a multiplicity of substrates arranged essentially parallel to one another from a substrate holding cassette and transporting the substrates to a corresponding one A plurality of essentially identical process units arranged one above the other, each of which has a substrate holder for holding an individual substrate, includes simultaneous loading of the process units, simultaneous and separate treatment of the substrates in the process units and simultaneous removal of the substrates from the process units. With this method, as already described above, good and uniform treatment of the substrates with high throughput can again be achieved.

In order to enable the substrates to be treated with a greater distance between them than their distance in the substrate receiving cassette, the distance is increased after the substrates have been removed from the substrate receiving cassette and before the simultaneous treatment. In one embodiment of the invention, the distance is at least partially increased by moving the substrate receptacles of the process units. At the same time, as an alternative, the distance is preferably at least partially increased by moving substrate receptacles of a handling device for loading and unloading the process units. In combination with a movement of the substrate receptacles, the handling device only has to provide a slight spread, so that their construction can be simplified; On the other hand, in an alternative embodiment, the handling device can carry out a complete spreading of the substrates, so that only a single spreading mechanism has to be provided.

In order to reduce the maximum required lifting height of external substrates and thus to simplify the construction of a spreading mechanism, the distance is preferably increased from a vertical central position by moving the substrates up and down.

In a preferred embodiment of the invention, at least one fluid is directed onto the substrate in each process unit during the treatment. For a simple construction of the device and to achieve uniform process results, the fluid is preferably conducted from a common media supply to the respective process units.

In one embodiment of the invention, the treatment takes place in a common process chamber, while in an alternative embodiment the treatment takes place in separate process chambers. In particular in the case of a treatment in a common process chamber, the treatment at least partially comprises a gas / steam treatment. With gas / steam treatment, there is no risk or only a reduced risk that, despite treatment in a common process chamber, different process conditions occur in the area of the individual process units. In particular in the case of a treatment in the individual process chambers, the treatment at least partially comprises a wet chemical treatment and / or a gas treatment. The last treatment step preferably includes drying in order to prevent wet or moist substrates from contaminating the substrates themselves or the environment.

In a particularly preferred embodiment of the invention, after removal from the process chambers, the substrates are transported to and loaded into a substrate holding cassette in order to enable connection to existing systems in which the substrate holding cassettes keep the substrates at a distance that is less than the minimum distance between the plurality of process units. The distance between the substrates after the treatment and before the inclusion in the substrate-receiving cassette can be reduced. In a further preferred embodiment of the invention, the multiplicity of process units form a first group and, adjacent to the first group, at least a second group of essentially identical process units arranged one above the other is preferably provided, which in the same way as the first group, but with a time delay, is operated. The throughput in the method according to the invention can be increased considerably by the second group. In addition, the time-shifted operation enables a good connection to continuously running process processes, since several groups of substrates instead of just one can be treated continuously. The substrates are preferably transported to the first and second groups at least partially by a common handling device in order to reduce the required components. Furthermore, the first and second groups preferably at least partially use a common media supply in order to provide the same process results across the groups and in turn to reduce the required process components. The first and second groups are preferably controlled in such a way that the same processes in the different groups do not take place at the same time in order to limit the maximum requirement for the common media supply to the maximum requirement of a single group.

The present invention is particularly suitable for the treatment of semiconductor wafers. In addition, however, it is also suitable for other substrates, in particular flat substrates with fine structures, such as, for example, glass plates for mask production or flat screens.

The object on which the present invention is based is further achieved by a device for the simultaneous transport of a multiplicity of substrates between a first unit carrying the multiplicity of substrates and a multiplicity corresponding to the number of substrates each of a second unit accommodating a single substrate, the Device a plurality of substrate receptacles arranged parallel to one another corresponding to the number of substrates and a device for changing one Has a distance between the substrate receptacles, specifically between a first distance that corresponds to the distance of the substrates in the first unit and a second distance that corresponds to the distance between receptacles of the second units. Such a device enables the simultaneous transport of a large number of substrates and a change in the distance between the substrates during the transport. This makes it possible to remove the substrates from a receiving cassette in which the substrates are kept closely spaced and, for example, to transport the substrates into a multiplicity of process units, the substrates within the individual process units being kept spaced apart by a large distance between them to enable individual treatment of the substrates.

The first distance is preferably smaller than the second distance. For a simple construction of the device, the substrate receptacles are preferably connected to one another via a telescopic arrangement that can be moved in and out pneumatically or hydraulically, for example. For good stability of the device, especially in the lateral direction, the substrate receptacles are guided along a guide member in the vertical direction. As a result, the drive unit for moving the substrate receptacles does not have to be made so stable since lateral loads are essentially absorbed via the guide member.

For a good connection to existing systems, the substrate receptacles, if they are spaced apart by the first distance, are preferably arranged in a vertical central region of the guide member. In this case, one of the substrate receptacles is preferably attached to the guide member in a stationary manner, while the others are movable along the guide member. The construction of the transport device can be simplified by providing a stationary substrate holder. In order to minimize the maximum lifting height for the individual substrates, the substrate receptacles can be moved at least partially in different vertical directions.

In a preferred embodiment of the invention, the substrate receptacles are attached and guided on the guide rail via a slide. At least one fastening element is provided for vertically offset attachment of at least one of the substrate receptacles to one of the carriages, so that the substrate receptacles can be spaced as closely as possible in the first position despite a certain height of the carriage. The fastening element can be formed integrally with the respective slide. A plurality of fastening elements are preferably provided for the respective vertically staggered attachment of one of the substrate receptacles to their respective sled, in order to enable the substrate receptacles to be closely spaced regardless of the height of the sled. For this purpose, at least two substrate receptacles with different vertical offsets to their respective slides are preferably arranged. To achieve good symmetry, two substrate receptacles that can be moved in different vertical directions are preferably arranged with the same vertical offset to their respective slides. In this way, symmetry can be achieved with respect to a horizontal central axis and furthermore it can be ensured that the substrates are evenly spaced.

In order to simplify the control of a movement unit, the substrate receptacles, the carriages and / or the guide member have stops for limiting the vertical movement of the substrate receptacles.

In order to enable loading and unloading of the first or second unit, a movement unit is preferably provided for laterally moving the guide member. The present invention is explained in more detail below on the basis of preferred exemplary embodiments of the invention with reference to the drawing; in the drawing shows:

Figure 1 is a schematic perspective view of a first embodiment of the device according to the invention in a first working position.

FIG. 2 shows a schematic perspective view of the device according to the invention according to FIG. 1 in a second working position; Fig. 3 is a schematic front view of an inventive

Treatment device of the present invention in a loading and unloading position;

FIG. 4 shows a schematic front view of the device according to FIG. 3 in a treatment position; Fig. 5 is a schematic perspective view of an alternative

Embodiment of the present invention in a first working position;

6 shows a schematic perspective view of the device according to FIG. 5 in a second working position; 7 is a schematic perspective view of a spreading device according to the present invention; FIG. 8 shows a schematic front view of the expanding device according to FIG. 7; 9 shows a schematic top view of the spreading device according to FIG. 7;

Fig. 10 is a schematic side view of an inventive

On spreading device and a treatment device according to the present invention; FIG. 11 shows a schematic front view of the spreading device according to FIG. 10 with a schematically indicated treatment device according to the present invention; 12 shows a schematic front view of a spreading device of the present invention according to an alternative exemplary embodiment in a retracted first position;

13 shows a schematic plan view of the spreading device according to FIG. 12 in a spread-out second position;

14 is a schematic perspective view of a substrate receiving unit according to the present invention;

Fig. 15 is a schematic plan view of an embodiment of a

Substrate treatment system according to the present invention; 16 A and B each show a schematic top view of an alternative exemplary embodiment for a treatment system according to the present invention.

1 shows a perspective view, partially broken away, of a treatment device 1 for semiconductor wafers 2. The treatment device 1 has a treatment part 4 and a transport part 5.

The treatment part 5 is formed by a housing 7 which has a process chamber 8. The housing 7, which is shown partially broken away, has a loading / unloading opening 10 which can be opened and closed via a suitable locking mechanism, not shown.

A multiplicity of process units 11 are provided within the process chamber of the housing 7. In the exemplary embodiment shown, a total of seven process units 11 are provided within the process chamber 8, although, of course, a different number of process units 11 can also be provided. The process units 11 each have a substrate holder 12, which can have the shape shown in FIG. 14, for example. These substrate receptacles 12 each have a plate-shaped base body 14 with a central opening 15. The central opening 15 has a shape corresponding to the wafers 2. The substrate receptacles 12 also have holding elements, not shown in FIG. 1, in order to hold the wafer 2 centered above the central opening, so that they both are essentially freely accessible from above and from below and can be treated on both sides.

Guide elements 17, which extend around corresponding guide rods 18, are attached to the base body 14 of the substrate receptacle 12. The guide rods 18 also extend through the base body 14 of the substrate receptacles 12. A total of four guide rods are provided in the process chamber 8, although of course a different number, in particular a smaller number, can also be provided.

The substrate receptacles 12 can be moved in a vertical direction along the guide rods 18 via a movement mechanism, not shown, in order to change the vertical distance between the substrate receptacles and the wafers 2 accommodated thereon, as will be explained in more detail below with reference to FIGS. 3 and 4. The substrate receptacles 12 thus form a vertically movable part of the process units 11.

The process units also have a stationary part, which for example can have a plurality of nozzles 20, 21, as is indicated schematically in FIGS. 3 and 4. The nozzles 20, 21 each together form the stationary process part of the process units in the chamber 8. Each of the nozzles 20, 21 can have a plurality of nozzles, for example in order to direct different treatment fluids onto the wafer 2 simultaneously and / or sequentially. As shown in FIG. 4, when the substrate receptacles are moved vertically apart, the nozzles 20 are located above the substrate receptacles 12, while the nozzles 21 are arranged below the substrate receptacles 12. This enables wafers 2 received on the substrate receptacles 12 to be treated on both sides. If only one-sided treatment of the wafers 2 is desired, the upper or lower nozzles 20, 21 can be omitted. Although the nozzles 20, 21 were designated as stationary, this only applies to their vertical position. In contrast, the nozzles 20, 21 can be movable in the horizontal direction in order to arrange the nozzles 20, 21 directly above and below that on the To allow substrate recordingή 12 received wafer 2, as will be explained in more detail below. Instead of or in addition to the nozzles 20, 21, other elements for treating the wafer 2 can also be provided, such as an ultrasound or megasound unit, brushes, etc.

The nozzles 20 are each connected to a common media supply 22, as indicated in FIG. 3, in order to ensure a uniform treatment of the tops of all wafers 2. In the same way, all nozzles 21 are connected to the common media supply 22 in order to ensure uniform treatment of all undersides of the wafers 2. If the upper and lower sides of the wafers 2 are to be treated in the same way, the nozzles 20 and 21 are provided with the common media supply 22.

The process units 11 each have a large number of feed lines for different process media, as well as a drying unit and an ultrasound or megasound unit, which are each arranged in the vertical direction in the process chamber 8, but can also be movable in the vertical direction.

The transport part 5 has a handling robot 23 with a housing 24 for receiving a drive unit. Above the housing 24, two arms 26, 27, one above the other and movable relative to one another, are provided. The lower arm 26 is connected at one end via a shaft 28 to the drive unit in the housing 24. At the end of the arm 26 opposite the shaft 28, one end of the arm 27 is movably attached. At the free end, the arm 27 carries a vertically extending Teieskopträger 30, which can be extended or retracted pneumatically or hydraulically, for example. The telescopic support 30 has a plurality of horizontally extending substrate receptacles 31 which can be moved in the vertical direction relative to one another via a telescopic mechanism of the telescopic support 30. Instead of a telescope arrangement, another mechanism for moving the substrate receptacles vertically relative can also be used. This should, however, have as few rubbing parts as possible to avoid the generation of contaminants.

The operation of the treatment device 1 will now be explained in more detail with reference to the figures.

The treatment device 1 is initially in a starting position in which the substrate receptacles 12 of the process units in the housing 7 are discharged. The substrate receptacles 12 are moved via the movement mechanism into the position shown in FIG. 1 or 3 and are thus located in the area of the loading / unloading opening 10 of the process chamber 8. The substrate receptacles 31 of the telescopic carrier 30 are in the vertical direction on a loading / Discharge distance a moved together, which corresponds to the distance between a plurality of wafers 2 in a substrate receiving cassette 33. The substrate receptacles 31 are moved under the wafer 2 in the cassette 33 in order to receive the wafer 2 thereon. The wafers 2 are then moved out of the cassette 33 by corresponding movement of the arms 26 and 27 of the handling robot 23. As soon as the wafers 2 are completely moved out of the cassette 33, the substrate receptacles 31 are moved apart in the vertical direction via the telescope carrier 30, which is referred to below as spreading apart. The substrate receptacles 31 are spread to a distance that corresponds to the distance of the substrate receptacles 12 of the process units 11 in the process chamber 8. The wafers 2 are then moved through the opening 10 into the process chamber 8 via a corresponding movement of the arms 26 and 27 of the handling robot 23. A wafer 2 is then placed on one of the substrate receptacles 12 and the substrate receptacles 31 of the handling robot 23 are moved out of the process chamber 8. The substrate receptacles 31 can be spread together with a movement of the arms 26, 27 of the handling robot 23 in order to ensure that the substrate receptacles 12 are loaded as quickly as possible. After loading the substrate receptacles 12, the loading / unloading opening 10 is closed and the substrate receptacles 12 are moved apart in the vertical direction, which is also referred to as spreading. In this spreading operation, a middle one of the substrate receptacles 12 is kept stationary, while the substrate receptacles 12 lying above the middle substrate receptacle 12 are moved upward and the substrate receptacles lying under the middle substrate receptacle 12 are moved downward. In this case, the substrate receptacles 12 are moved in such a way that at the end of their movement they are spaced apart with a uniform process distance b, which enables the individual processing of the wafers 2 by the respective process units 11.

Subsequently, the wafers 2 are each treated individually within their process units 11, the treatment being able to comprise a chemical, mechanical or other treatment, a gas or steam treatment being particularly preferred. Before or during the treatment of the wafers 2, the nozzles 20 and 21 can be pivoted in the horizontal direction in order to provide a direct arrangement above or below the wafers. During the treatment, the wafers 2 are further rotated about their central axis by the respective substrate receptacles 12.

After the respective treatment, the substrate receptacles 12 are moved together again in the vertical direction to the loading / unloading distance a. The opening 10 is opened and the wafer 2 are removed in the reverse order of loading operation by the handling robot 23, moved together, and the substrate-receiving cassette 33 is loaded into. ^{"Subsequently,} a new loading can take place.

The treatment device according to the invention thus enables the transport of a large number of wafers between a wafer holding cassette 33 and a large number of process units 11, which each hold a single wafer and treat it individually. The substrates are used during the Transport spread apart to create a distance between the substrates necessary for individual treatment.

FIGS. 5 and 6 show an alternative embodiment of the treatment device 1 according to the invention. 5 and 6, the same reference numerals are used as in the first exemplary embodiment, provided that the same or similar parts are designated.

The treatment device 1 is a device for wet chemical treatment of semiconductor wafers 2.

The treatment device 1 has a treatment part 4 and a transport part 5.

The treatment part 4 consists of a housing 37 with a plurality of process units 39 arranged horizontally one above the other, the uppermost of which is shown schematically. The process units are each separated from one another by horizontal partition walls 40, so that the process units 39 are each arranged within a separate process chamber 42.

Each process chamber 42 is assigned a loading / unloading opening 43, which can be opened and closed via a locking mechanism, not shown in detail. Instead of forming separate process chambers 42 for accommodating the process units 39 in a common housing 37, it is also possible to provide a separate housing for each process chamber 42 or process unit 39. The individual housings could then be stacked vertically one above the other. This structure would increase the flexibility with regard to the number of process units 39 arranged one above the other. In addition, the modular exchange of individual process units 39 would be simplified in the event of a defect within a single process unit 39. The process units 39 have essentially the same elements as the process units 11 described in the first exemplary embodiment. However, there is no vertical movement of substrate receptacles and, moreover, nozzle arrangements for introducing a treatment fluid can be designed to be stationary in such a way that they always have an essential one Extend part of the wafer 2 to be treated.

A control and media supply unit 45 is provided in the housing 37 adjacent to the respective process chambers 42. The control and media supply unit is provided jointly for all process units and in particular the process media used come from a common supply unit in order to provide uniform treatment results within the respective process units.

The transport part 5 of the treatment device 1 has a handling robot 47 and a separate spreading unit 49. The handling robot 47 has a similar structure to the handling robot 23 according to the first exemplary embodiment, but no telescopic support is provided for spreading the wafers 2. The handling robot 47 has a housing 52 for receiving a drive unit, and arms 53, 54, which are coupled to the drive unit in the housing 52 via a shaft. The arms 53, 54 are connected to one another and to the shaft 55 in the same way as the arms 26, 27 of the handling robot 23 of the first exemplary embodiment. The shaft 55 is movable in the vertical direction. At the free end of the arm 54, a vertically extending support 57 with a plurality of horizontally extending substrate receptacles 58 is provided. The number of substrate receptacles 58 corresponds to the number of wafers 2 to be conveyed and also to the number of process units 39. In the exemplary embodiment shown, both substrate receptacles 58 and seven process units 39 are provided. The expansion unit 49, which is also in the

7 to 9, has a vertically extending guide element 60 with a vertically extending central opening 61. A vertically extending guide slot 63 is provided in a side surface of the guide element 60 and communicates with the central opening 61.

A number of vertically movable substrate receptacles 65 corresponding to the number of process units 39 is provided on the guide element 60. In the current embodiment, seven substrate receptacles 65 are thus provided, the middle of which is stationary, i.e. is not vertically movable, is formed.

The substrate receptacles 65 are, as can best be seen in FIG. 9, attached to a slide 67 which surrounds the guide element 60 in a U-shape in order to provide lateral guidance. In addition, a guide pin 68 is provided, which is shown in broken lines in FIG. 9. The guide pin 68 is fixedly connected to the slide 67 and extends through the guide slot 63 into the central opening 61 of the guide element 60. There, the guide pin 68 is coupled in a suitable manner to a holding and drive unit (not shown) for vertically moving the guide pin 68 and thus the slide 67 or the substrate holder 65.

As mentioned above, the middle one of the substrate receptacles 65 is stationary. The middle substrate receptacle 65 is in a vertical middle position of the guide element 60 and the guide slot 63. The substrate receptacles lying above or below the stationary substrate receptacle 65 can be moved up or down by the movement mechanism (not shown). The substrate receptacles 65 are movable in such a way that the distance between them always remains the same, which means that the uppermost and lowermost substrate receptacles each travel the longest distance.

The operation of the treatment device 1 according to the second exemplary embodiment is explained in more detail below with reference to FIGS. 5 to 11. The treatment device is initially in a starting position, ie there are no wafers 2 in the respective process units 39. The substrate receptacles 65 are moved together and are located in a vertical central region of the guide element 60.

The handling robot 47 removes a large number of wafers 2 from a substrate receiving cassette 33 in the same manner as described in the first exemplary embodiment. It should be noted that the substrate receptacles 58 of the handling robot 47 are at a distance which corresponds to the distance of the wafers 2 in on the substrate-receiving cassette 33 corresponds.

This distance also corresponds to the distance between the substrate receptacles 65 when they are moved together in a vertical central region of the guide element 60, as shown in FIG. 5. The removal process is best shown in Fig. 5.

The handling robot 47 then moves the wafers 2 to the spreading unit 49 and in each case deposits one wafer 2 on one of the substrate receptacles 65, as shown in FIG. 6. FIG. 6 shows how the handling robot 47 has placed the wafers 2 on the substrate receptacles 65 of the spreading unit 49 and the substrate receptacles 58 of the handling robot 47 have already been partially withdrawn.

When the substrate receptacles 58 are completely withdrawn, the substrate receptacles 65 of the spreading unit 49 are moved apart in the vertical direction, which is also referred to as spreading. The middle substrate receptacle 65 is held stationary and the three substrate receptacles located above it are moved upward, while the three substrate receptacles 65 located below are moved downward. The substrate receptacles 65 are moved such that a uniform distance c is formed between them, which is the distance between the loading / unloading openings 43 in the housing 37 corresponds. The spread position of the substrate receptacles 65 can be clearly seen, for example, in FIGS. 7 and 8.

When the substrate receptacles 65 are in their spread position, they are aligned with the loading / unloading openings 43 of the process chambers 42, as can best be seen in FIG. 10. The vertically extending guide element 60 is then moved laterally in the direction of the housing 37 via a suitable movement mechanism along a guide rail 70 in order to introduce the wafers 2 into the process chamber 42, as is best shown in FIG. 11. the wafers 2 are deposited in the process units 39 and the guide element 60 is moved back. The loading / unloading openings are then closed and the wafers 2 are each treated individually within a process unit 39. In particular, wet-chemical treatment of the wafers 2 with subsequent drying takes place. After the treatment, the wafers 2 are removed from the process units 39 in reverse order for loading and moved back to the substrate receiving cassette 33.

FIGS. 12 and 13 show an alternative embodiment of an expansion unit 49. In the description of FIGS. 12 and 13, the same reference symbols are used as in the previous exemplary embodiment, provided that the same or similar elements are designated.

In the spreading unit 49 according to FIGS. 5 to 11, the minimum distance between the substrate receptacles 65 is determined by the height of the slide 67. For increased stability, however, it is advantageous to choose a height for the slide 67 which is greater than the distance between the wafers 2 in the substrate receiving cassette 33. For increased stability of the slide with a simultaneous close spacing of the substrate recordings, this is Embodiment according to Figures 12 and 13 provided.

The spreading unit 49 according to FIGS. 12 and 13 has, as in the previous exemplary embodiment, a guide element 60 with a guide tion slot 63 in a side wall of the guide element. Furthermore, seven slides 67 are provided which, like in the previous exemplary embodiment, grip around the guide element 60 in a U-shape and are in contact with a central opening of the guide element 60 via a pin (not shown). Of the seven slides 67, the top three and the bottom three can be moved along the guide slot 63 via a movement mechanism (not shown). The middle of the slide 67 is stationary. An elongated, vertically extending support element 72 is attached to each of the three uppermost and the three lowest carriages 67. The carrier element 72 is attached to its respective carriage 67 in such a way that it extends over a lower edge (in the case of the three upper carriages 67) or an upper edge (in the case of the three lower carriages 67). Substrate receptacles 65 for receiving semiconductor wafers 2 are provided at the respective free ends of the carrier elements 72. The carrier elements 72 thus carry the substrate receptacles 65 offset with respect to a main body of the slide 67. The offset of the carrier elements 72 on the outer slide 67 is greater than the offset on the slide 67 adjacent to the center. That is, the carrier elements 72 become slide-to-slide to the middle slide, which has no carrier element 72, always shorter, as a result of which the vertical offset with respect to the slide 67 is reduced. As a result, as can be seen in FIG. 12, a relatively small distance between the substrate receptacles 65 can be achieved when the carriages 67 are moved together. In particular, a much smaller distance can be achieved than a distance corresponding to the height of the slides 67. Thus, with high guiding stability, the carriage 67 can nevertheless achieve a small distance between the substrate receptacles 65, which corresponds to the spacing of the wafers 2 in a substrate receptacle cassette 33. In the expanded state according to FIG. 13, the substrate receptacles 65 can be moved apart in such a way that the substrates 2 can be loaded into individual process chambers.

14 shows a perspective view of a substrate receptacle 75 which, for example, within the process units of the first embodiment game or after minor modification can be used in the process units of the second embodiment. The substrate receptacle 75 has a base body 77 with a central opening 78. A ring element 80 is provided on the inner circumference of the central opening 78, which is rotatably mounted on the base body 77 and can be rotated via a drive, not shown. A plurality of holders 82 are attached to the ring element 80. The holders 82 extend obliquely upward from the ring element, so that they are inclined radially towards an axis of rotation of the ring element 80. The holders 82 each have a support surface for the wafer 2 at their free end and hold it in height above the base body 77. This prevents the treatment medium flowing away from the wafer 2 from reaching the inner circumference of the base body 77 at high speeds of the ring element and from this splashes back onto the wafer 2. Four upper guide blocks 84 and four lower guide blocks 85 are attached to the upper and lower sides of the base body 77. The guide blocks 84 and 85 each have through openings 87 which are aligned with a corresponding through opening in the base body 77. The through openings are provided so that, for example, a guide rod, such as the guide rod 18 according to FIG. 1, can extend through it. The guide blocks 84, 85 thus provide good guidance along a corresponding guide element, such as a guide rod, if the substrate receptacles 75 are designed to be movable in the vertical direction.

In the event that the substrate receptacles 75 are used in a stationary manner, for example in the second exemplary embodiment according to FIGS. 5 to 11, the guide blocks 84, 85 can be omitted. Instead of the guide blocks 85, spacer elements can then be used around the base body 77 spaced above a partition 40 of a process unit 39. This is at least advantageous if the wafers 2 are treated on both sides. If the wafers 2 are treated on one side from above, it would not be necessary to base the body 77 of the substrate receptacle 75 over a partition 40 To keep process unit 39 spaced. The substrate receptacle 75 is capable of rotating the wafer 2 during its treatment via the ring element 80, as a result of which a homogeneous and uniform treatment of the wafer 2 with a process fluid can be achieved. In addition, good drying of the wafers 2 can be promoted by the rotation, in particular after a wet chemical treatment.

15 shows the basic structure of a treatment device 1 according to FIGS. 5 to 11 in a schematic plan view. The following can be seen from left to right in FIG. 15: a substrate holding cassette 33 for holding a plurality of wafers 2 arranged vertically one above the other; a handling robot 47; a spreading unit 49 and a housing 37. The handling robot has arms 53, 54 and a plurality of substrate receptacles 58 arranged vertically one above the other. The arms 53, 54 can be moved relative to one another and relative to a housing 52 of the handling robot 47. The substrate receptacles 58 are attached to the arm 54 via a corresponding carrier. By appropriately controlling the arms 53, 54 and the carrier, the substrate receptacles 58 can be moved laterally as well as in a rotational movement, as indicated by the double arrows A and B.

The spreading device 49 has a plurality of substrate receptacles 65 lying vertically one above the other and movable in the vertical direction. The spreading unit 49 can be moved laterally, as indicated by the double arrow C. The spreading unit 49 can be moved towards and away from the housing 37. The housing 37 has a multiplicity of process units arranged vertically one above the other. The process units each have their own process chamber 42 with a loading / unloading opening, which can be opened and closed via a locking mechanism 90. A substrate holder for a wafer 2 is provided in each case within the process chambers 42. The wafers 2 are each rotatably held on the substrate receptacles, as indicated by the arrow D. Adjacent to the process chambers 42, a control and media supply unit 45 is provided for the multiplicity of process units.

During the operating sequence, the handling robot 47 first removes a large number of wafers 2 from the substrate holding cassette 33, transports them together to the spreading unit 49 and deposits them on the substrate holding devices 65, which are in a collapsed state. The substrate receptacles 65 are then spread out, so that the wafers 2 are also spread out, i.e. Their distance is increased in such a way that the distance corresponds to the distance between the loading / unloading openings of the plurality of process chambers 42. The spreading unit 49 is then moved laterally in the direction of the housing 37 and the wafers 2 are loaded directly from the substrate receptacles 65 into the respective process chambers 42. The spreading unit 49 is then moved back and the closing mechanism 90 closes the process chambers 42. Within the process chambers, the wafers 2 are optionally treated using different treatment fluids, in particular wet-chemically, and then dried in a suitable manner. Among other things, ultrasound or megasound can be used during the treatment to promote the treatment result.

After the treatment, the wafers 2 are removed in the reverse order for loading and transported back into the substrate holding cassette 33.

16 A shows an expanded treatment device with a substrate receiving cassette 33, a handling robot 47, a total of four spreading units 49 arranged next to one another and a total of four housings 37 lying next to one another for receiving process units. The substrate receiving cassette, the handling robot 47 in its basic position, a spreading unit 49 and a housing 37 lie on a first line. The spreading units 49 lie on a second line which extends perpendicular to the first. In the same way, the housings 97 lie on one third line that extends perpendicular to the first line. In this expanded system, a single handling robot 47, which can be moved perpendicular to the first line, loads and unloads a plurality of spreading units 49, each of which loads and unloads a large number of process units. This arrangement enables an even greater throughput during wafer treatment, since a large number of wafers 2 can be treated simultaneously within each housing 37. The respective housings 37 are assembled offset from one another, which enables a continuous treatment of a large number of wafers. A single handling robot 47 can operate a large number of spreading units 49.

Of course, depending on the length of the treatment time of the wafers in the individual process units, it is also possible to provide only a single spreading unit 49, which can be moved in the same way as the handling robot 47 in order to equip a plurality of housings 37 with a plurality of process units 39 each, as is the case 16B. The process units 39 in the different housings 37 can be connected to a common control and media supply unit in order to achieve good homogeneity across the different process units. In this case, the process units 39 within a housing 37 are simultaneously controlled as a group and supplied with media. The process units in the other housings are controlled offset and supplied with media. It is possible to control the process units within the different housings offset from one another in such a way that different treatment steps take place within the different housings. As a result, the maximum requirement for the control and media supply unit can be reduced, since, for example, only the amount of treatment medium that is required for the large number of process units in a single housing 37 has to be kept available.

Although the invention has been described with reference to preferred exemplary embodiments of the invention, it is not restricted to the specifically illustrated exemplary embodiments. For example, the treatment devices also suitable for other substrates, in particular flat substrates with fine structures, such as, for example, glass plates for mask production or flat screens. Furthermore, in the first exemplary embodiment, in which a multiplicity of process units are arranged in a common chamber, it is also possible to spread the substrates completely before loading the chamber and to provide stationary substrate receptacles within the common chamber. This could be achieved solely by means of the handling robot 23 with a correspondingly large telescopic carrier, or by a combination of handling robot 47 and spreading unit 49, as in the exemplary embodiment according to FIGS. 5 to 11. In addition, the combination of handling robot 47 and spreading unit 49, a two-stage spreading of the substrates is possible, in which the handling robot 47, for example, performs a partial spreading, like the handling robot 23, and the spreading unit 49 provides a full spreading. The features of the different exemplary embodiments can be freely combined with one another, provided that they are compatible.

Claims

claims 1. Device 1 for the simultaneous treatment of individual substrates 2, in particular in semiconductor production, with a multiplicity of essentially identical process units 11 arranged one above the other, 39, which each have a substrate holder 12, 75 for holding an individual substrate 2, and a handling device 23, 47, 49 with a number of substrate holders corresponding to the number of process units 11, 39 for simultaneous loading and unloading of a large number of substrates 2 into and out of the process units 11, 39th 2. Device according to claim 1, characterized by at least one spreading unit 30, 49 for vertically moving the substrates 2 relative to one another in order to change the distance between the substrates 2. 3. Device according to claim 1 or 2, characterized in that the process units 11 are arranged in a common housing 7 with a common process chamber 8. 4. The device according to claim 3, characterized by a common opening 10 in the housing 7 for loading and unloading substrates 2, wherein the opening 10 has a height which is smaller than the distance between a top and a bottom of the one above the other Process units 11. 5. The device according to claim 4, characterized in that the opening is arranged substantially centrally along the height of the housing 7. 6. Device according to one of claims 3 to 5, characterized by a movement unit with a spreading mechanism for vertically moving substrate receptacles 12 of the process units 11 in the housing 7. 7. The device according to claim 1 or 2, characterized in that the process units 39 are each arranged in a separate process chamber 42, each having its own opening 43 for loading and unloading the substrates 2. 8. Device according to one of the preceding claims, characterized in that the handling device 23 has a spreading mechanism 30 for moving substrate receptacles 31 vertically. 9. The device according to claim 8, characterized in that the spreading mechanism 30 has at least one telescopic arrangement. 10. The device according to claim 2, characterized in that the Spreading unit 49 has a vertical guide member 60 with a number of substrate receptacles 65 corresponding to the number of process units 11, 39. 11. The device according to claim 10, characterized in that the substrate receptacles 65 are arranged in a non-spread position in a vertical central region of the guide member 60. 12. Device according to one of claims 10 or 11, characterized in that one of the substrate receptacles 65 is fixedly mounted on the guide member 60, while the others are movable along the guide member 60. 13. Device according to one of claims 8 to 12, characterized in that the substrate receptacles 31, 65 are at least partially movable in different vertical directions. 14. Device according to one of claims 10 to 13, characterized in that the substrate receptacles 31, 65 and / or the guide member 60 have stops for limiting the vertical movement of the substrate receptacles. 15. The device according to one of claims 10 to 14, characterized by a movement unit for laterally moving the guide member 60. 16. Device according to one of the preceding claims, characterized in that the handling device 23, 47 has a movement unit for transporting the substrates 2 between a substrate receiving cassette 33 and the process units 11, 39 or the substrate receptacles 65 of the guide member 60. 17. Device according to one of the preceding claims, characterized in that the process units 11, 39 have at least one common media supply. 18. Device according to one of the preceding claims, characterized in that the process units 11, 39 each have a rotatable substrate holder 12, 75. 19. Device according to one of the preceding claims, characterized in that the process units 11, 39 each have a plurality of Supply lines for process media included. 20. Device according to one of the preceding claims, characterized in that the process units 11, 39 have a drying unit. 21. Device according to one of the preceding claims, characterized in that the process units 11, 39 each have an ultrasound or megasound unit. 22. The apparatus according to claim 7 or 4, characterized by at least one device for opening and closing the opening 10 43rd 23. Device according to one of the preceding claims, characterized in that the plurality of process units 11, 39 arranged one above the other forms a first group of process units, and that adjacent to the first group a second group of essentially identical process units 11 arranged one above the other, 39 is provided, at least parts of the handling device 23, 47, 49 being movable for the first group in such a way that they can also be used for loading and unloading the second group. 24. A method for treating substrates, in particular in the manufacture of semiconductors, with the following method steps: a. simultaneous removal of a multiplicity of substrates arranged essentially parallel to one another from a substrate receiving cassette; b. Transporting the substrates to a corresponding plurality of essentially identical process units arranged one above the other, each of which has a substrate holder for receiving a single substrate; c. simultaneous loading of the process units; d. simultaneous treatment of the substrates in the process units; and e. simultaneous removal of the substrates from the process units. 25. The method according to claim 24, characterized in that the distance of the substrates after the removal of the substrates from the substrate receiving cassette and before the simultaneous treatment is increased. 26. The method according to claim 25, characterized in that the distance is at least partially increased by moving the substrate receptacles of the process units. 27. The method according to claim 25, characterized in that the distance is at least partially increased by moving substrate receptacles of a handling device for loading and unloading the process units. 28. The method according to claim 25, characterized in that the distance is increased completely by moving substrate receptacles of a handling device for loading and unloading the process units. 29. The method according to any one of claims 25 to 28, characterized in that the distance from a vertical central position is increased by moving the substrates up and down. 30. The method according to any one of claims 24 to 29, characterized in that at least one fluid is passed onto the substrate in each process unit during the treatment. 31. The method according to claim 31, characterized in that the fluid is directed from a common media supply to the respective process units. 32. The method according to any one of claims 24 to 32, characterized in that the treatment takes place in a common process chamber. 33. The method according to any one of claims 24 to 31, characterized in that the treatment takes place in separate process chambers. 34. The method according to any one of claims 24 to 33, characterized in that the treatment at least partially comprises a gas / steam treatment. 35. The method according to any one of claims 24 to 34, characterized in that the treatment at least partially comprises a wet chemical treatment. 36. The method according to claim 35, characterized in that the last treatment step comprises drying. 37. The method according to any one of claims 24 to 36, characterized in that the substrates are transported to and loaded into a substrate receiving cassette after removal, and in that the distance between the substrates after the treatment and before the inclusion in the substrate receiving cassette is reduced becomes. 38. The method according to any one of claims 24 to 37, characterized in that the plurality of process units form a first group and adjacent to the first group there is provided at least a second group of essentially the same, superimposed process units, which are in the same How the first group is operated, but with a time delay. 39. The method according to claim 38, characterized in that the transport of substrates to the first and second groups is carried out at least partially by a common handling device. 40. The method according to claim 38, characterized in that the first and second groups at least partially use a common media supply. 41. A method according to claim 40, characterized in that the first and second groups are controlled such that the same processes do not take place simultaneously. 42. Device 23, 47, 49 for the simultaneous transport of a plurality of Substrates between a first unit 33 carrying the plurality of substrates and a plurality of second process units 11, 39 each corresponding to the number of substrates, each having a single substrate, with a plurality of substrate receptacles 31, 58 arranged parallel to one another corresponding to the number of substrates . 65 and a device for changing a distance between the substrate receptacles 31, 58, 65, namely essentially between a first distance which corresponds to the distance between the substrates 2 in the first unit 30 and a second distance which see the distance between the corresponds to second process units 11, 39. 43. Device according to claim 42, characterized in that the first distance is smaller than the second distance. 44. Device according to claim 42, characterized in that the substrate receptacles 31 are connected to one another via a telescope arrangement 30. 45. Device according to one of claims 42 to 44, characterized in that the substrate receptacles 65 along a guide member 60 in Are guided vertically. 46. Device according to claim 45, characterized in that the substrate receptacles 65, if they are spaced apart by the first distance, are arranged in a vertical central region of the guide member 60. 47. Device according to one of claims 45 or 46, characterized in that one of the substrate receptacles 65 is stationary on the guide member is attached while the others are movable along the guide member 60. 48. Device according to one of claims 42 to 47, characterized in that the substrate receptacles 65 are at least partially movable in different vertical directions. 49. Device according to one of claims 42 to 48, characterized in that the substrate receptacles 65 are attached and guided on the guide member 60 via a slide 67. 50. Device according to claim 49, characterized by at least one fastening element 72 for vertically offset attachment of at least one of the substrate receptacles 65 to one of the slides 67. 51. Device according to claim 50, characterized by a plurality of fastening elements 72 for the respective vertically offset attachment of one of the substrate receptacles 65 to their respective slide 67. 52. Device according to claim 51, characterized in that at least two substrate receptacles 65 are arranged with different vertical offsets to their respective slide 67. 53. Apparatus according to claim 50 or 51, characterized in that in each case two substrate receptacles 65 which can be moved in different vertical directions are arranged with the same vertical offset with respect to your respective slide. 54. Device according to one of claims 45 to 48, characterized in that the substrate receptacles 65, the slide 67 and / or the guide member 60 have stops for limiting the vertical movement of the substrate receptacles 65. 55. Device according to one of claims 45 to 54, characterized by a movement unit for laterally moving the guide member 60. 56. Device according to one of claims 42 to 55, characterized by a pneumatic or hydraulic unit for changing the distance between the substrate receptacles.