Vertical Batch Furnace Assembly

Abstract

To provide a vertical batch furnace assembly of which a cassette handling mechanism has an improved transfer speed and / or an improved reach.SOLUTION: A vertical batch furnace assembly for processing wafers comprises a cassette handling space, a wafer handling space, and a first wall separating the cassette handling space from the wafer handling space. The first wall has at least one wafer transfer opening in front of which a wafer transfer position for a wafer cassette is provided. The cassette handling space comprises a cassette storage, and a cassette handling mechanism. The cassette storage has a plurality of cassette storage positions and is configured to store a plurality of wafer cassettes. The cassette handling mechanism comprises a first cassette handler which is configured to transfer wafer cassettes between a first set of the cassette storage positions and the wafer transfer position. The cassette handling mechanism is provided with a second cassette handler which is configured to transfer wafer cassettes between a second set of the cassette storage positions and the wafer transfer position.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure generally relates to a vertical batch furnace assembly for processing wafers. [Background technology]

[0002] Most vertical batch furnace assemblies include a cassette handling space for receiving and storing wafer cassettes therein. Such cassette handling spaces typically include a cassette entry / exit port, a cassette storage section, and a cassette handling mechanism for transferring wafer cassettes between a wafer transfer position, where the wafer cassettes may be exchanged between the vertical batch furnace assembly and the clean room environment in which the vertical batch furnace assembly is housed. The received wafer cassette may be placed in a wafer transfer position, from which wafers may be removed from the wafer cassette and loaded into a wafer boat for processing.

[0003] The cassette storage section may have a plurality of cassette storage locations, each of which may store a wafer cassette. The cassette storage locations may be arranged in a storage rack, for example, comprising a storage carousel. A typical cassette handling mechanism may comprise an elevator mechanism and a robotic arm so that the input / output ports, the wafer transfer locations, and all of the wafer storage locations may be reached. The elevator mechanism may provide vertical movement of the cassette handling mechanism to reach the cassette storage locations at various vertical heights. The robotic arm may provide two-dimensional horizontal movement to reach at least some of the storage locations. Summary of the Invention [Means for solving the problem]

[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detailed Description of Exemplary Embodiments of the Disclosure below. This Summary is not intended to identify key features or essential features of the claimed subject matter or to be used to limit the scope of the claimed subject matter.

[0005] It is understood that typically multiple wafer cassettes may need to be unloaded and loaded into an entire wafer boat. It is understood that it may be desirable to store as many wafer cassettes as possible within the cassette operation space. The cassette operation space may have a rectangular shaped footprint. A sophisticated cassette handling mechanism may need to have a sufficient reach so that it can reach cassette storage locations within the cassette operation space. The speed at which the cassette handling mechanism can transport cassettes within the cassette operation space may be important to the efficiency of the vertical batch furnace assembly.

[0006] It may therefore be an object to provide a vertical batch furnace assembly in which the cassette handling mechanism has an improved transfer speed and / or an improved reach.

[0007] To that end, a vertical batch furnace assembly according to claim 1 may be provided. More specifically, a vertical batch furnace assembly for processing wafers may be provided. The vertical batch furnace assembly may comprise a cassette operation space, a wafer operation space, and a first wall separating the cassette operation space from the wafer operation space. The first wall may have at least one wafer transfer opening and may provide a wafer transfer position for a wafer cassette at a front thereof and at a side of the first wall directed towards the cassette operation space. The cassette operation space may comprise a cassette storage section, and a cassette handling mechanism. The cassette storage section may have a plurality of cassette storage positions and may be configured to store a plurality of wafer cassettes comprising a plurality of wafers. The cassette handling mechanism may comprise a first cassette handler configured to transfer the wafer cassette between a first set of cassette storage positions and a wafer transfer position. The cassette handling mechanism may comprise a second cassette handler configured to transfer the wafer cassette between a second set of cassette storage positions and a wafer transfer position.

[0008] In order to summarize the invention and the advantages achieved over the prior art, some objects and advantages of the invention have been described hereinabove. Of course, it should be understood that not all such objects or advantages may necessarily be achieved by any particular embodiment of the invention. Thus, for example, a person skilled in the art will recognize that the invention may be implemented or performed to achieve or optimize one advantage or a group of advantages taught or suggested herein, without necessarily achieving other objects or advantages taught or suggested herein.

[0009] Various embodiments are claimed in the dependent claims, which will be further elucidated with reference to the examples shown in the figures. The embodiments can be combined or can also be applied separately from one another.

[0010] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of several embodiments, taken in conjunction with the accompanying figures. The invention is not limited to any particular embodiment disclosed.

[0011] While the specification concludes with claims which particularly point out and distinctly claim what are believed to be embodiments of the present disclosure, the advantages of the embodiments of the present disclosure may be more readily ascertained from a description of several example embodiments of the present disclosure when read in conjunction with the accompanying drawings. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a top partial cross-sectional view of an example vertical batch furnace assembly in accordance with the present description. [Diagram 2] 2 is a top cross-sectional view of the cassette operation space of the example in FIG. 1. [Diagram 3] FIG. 13 is a side cross-sectional view of another example of a cassette manipulation space in accordance with the present description. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In the present application, similar or corresponding features are indicated by similar or corresponding reference symbols. The description of the various embodiments is not limited to the examples shown in the figures, and the reference numerals used in the detailed description and claims are not intended to limit the description of the embodiments, but are included to clarify the embodiments by reference to the examples shown in the figures.

[0014] Although several embodiments and examples are disclosed below, those skilled in the art will understand that the present invention extends beyond the specifically disclosed embodiments and / or applications of the present invention, as well as obvious modifications and equivalents thereof. Therefore, it is intended that the scope of the disclosed invention should not be limited by the specific disclosed embodiments described below. The figures presented herein are not meant to be actual illustrations of any particular materials, structures, or devices, but merely idealized representations used to describe embodiments of the present disclosure.

[0015] As used herein, the term "wafer" can refer to any underlying material or materials that can be used upon which devices, circuits, or films can be formed.

[0016] In the most general terms, the present disclosure may provide a vertical batch furnace assembly 10 for processing wafers. The vertical batch furnace assembly 10 may comprise a cassette operation space 12, a wafer operation space 14, and a first wall 16 separating the cassette operation space 12 from the wafer operation space 14. The first wall 16 may have at least one wafer transfer opening 18, and at its front, on the side of the first wall 16 facing the cassette operation space 12, a wafer transfer position 20 for a wafer cassette 22 may be provided. The cassette operation space 12 may comprise a cassette storage section, and a cassette handling mechanism 26, 28. The cassette storage section may have a plurality of cassette storage positions 24 and may be configured to store a plurality of wafer cassettes 22 comprising a plurality of wafers. The cassette handling mechanism 26, 28 may comprise a first cassette handler 26 configured to transfer the wafer cassette 22 between a first set 30 of cassette storage positions 24 and the wafer transfer position 20. The cassette handling mechanism 26 , 28 may include a second cassette handler 28 configured to transfer wafer cassettes between the second set 32 ​​of cassette storage locations 24 and the wafer transfer location 20 .

[0017] An advantage of the above described vertical batch furnace assembly is that each cassette handler 26, 28 can reach at least some of the cassette storage locations 24 within the cassette handling space. There is no single robot arm that needs to be able to reach every cassette storage location. It is sufficient to have the first cassette handler 26 transfer to and from the first set 30 of cassette storage locations 24 and the second cassette handler 28 transfer to and from the second set 32 ​​of cassette storage locations 24, as long as the first and second sets 30, 32 together include all the cassette storage locations 24 of the cassette storage section. By carefully selecting the positions of the first and second cassette handlers 26, 28 within the cassette handling space 12 relative to the cassette locations 24, each can have a limited reach, but together they can still cover all the cassette storage locations 24 within the entire cassette handling space 12. The first cassette handler 26 can be located, for example, at or near a first end of the cassette operation space 12, while the second cassette handler 28 can be located at or near a second end of the cassette operation space 12 opposite the first end. The first set 30 of cassette storage locations 24 would then cover approximately half of the cassette operation space 12 near the first end, while the second set 32 ​​of cassette storage locations 24 would cover approximately another half of the cassette operation space 12 near the second end. Both the first cassette handler 26 and the second cassette handler 28 can have a much smaller reach, since they only need to cover approximately half of the area associated with known cassette handlers. The smaller reach means that less sophisticated, and therefore less costly, cassette handlers can be used.

[0018] Secondly, by having two cassette handlers 26, 28, both cassette handlers 26, 28 can transfer wafer cassettes towards the wafer transfer location. They can do so simultaneously. This means that while the first cassette handler 26 is placing a wafer cassette 22 at the wafer transfer location 20, the second wafer handler 28 can already retrieve another wafer cassette 22 from the cassette storage location 24 of the cassette storage. By judiciously selecting where the wafer cassettes 22 should be stored and by judiciously selecting the order in which the wafer cassettes 22 are transferred from the cassette storage to the wafer transfer location 20, a high overall transfer capacity of the cassette handling mechanism 26, 28 can be achieved. With such a scheme, the overall transfer capacity of the cassette handling mechanism can simply be the sum of the transfer capacities of the first and second cassette handlers 26, 28. To improve the overall transport capacity of the cassette handling mechanisms 26, 28, the transport speed of both the first and second cassette handlers 26, 28 only needs to exceed half the transport speed of the prior art cassette handlers. A slower transport speed means that a less robust and therefore less expensive cassette handler can be used. With a lower transport speed, the wafer cassette 22 can also be transported more smoothly, reducing the risk of particulate release that could damage the wafers.

[0019] The use of first and second cassette handlers 26, 28 allows for both improved reach and increased transport capacity over prior art cassette handler mechanisms in a vertical batch furnace.

[0020] In an embodiment, the first and second cassette handlers 26, 28 may each include a cassette handler arm 34 and an elevator mechanism 36. The elevator mechanism 36 may be configured to reach wafer cassettes 22 located at cassette storage locations 24 at various vertical heights within the cassette handling space 12.

[0021] In an embodiment, the elevator mechanism 36 of the first cassette handler 26 may be located at or adjacent to the second wall 38, and the elevator mechanism 36 of the second cassette handler 28 may be located at or adjacent to the third wall 40. The second and third walls 38, 40 may bound the cassette handling space 12 at opposite ends.

[0022] When the elevator mechanisms 36 of the first and second cassette handlers 26, 28 are positioned at or adjacent to opposite ends of the cassette operating space 12, the cassette handlers 26, 28 themselves will also be positioned at or adjacent to opposite ends of the cassette operating space 12. In that case, the first and second sets of cassette storage locations 30, 32 will also be positioned at or adjacent opposite ends of the cassette operating space 12. The first set 30 of cassette storage locations 24 may be positioned at or adjacent the second wall 38, while the second set 32 ​​of cassette storage locations 24 may be positioned at or adjacent the third wall 40. The first set 30 of cassette storage locations 24 will cover approximately half of the cassette operating space 12 closest to the first end, while the second set 32 ​​of cassette storage locations 24 will cover approximately the other half of the cassette operating space closest to the second end. Because both the first cassette handler 26 and the second cassette handler 28 only need to cover approximately half the area of ​​known cassette handlers, their respective reach can be much smaller. The smaller reach means that less complex and more robust cassette handlers 26, 28 are possible, which is beneficial in terms of manufacturing costs.

[0023] In an embodiment, the cassette storage can be configured to store 10 to 50 wafer cassettes 22. The cassette storage can be configured to store, for example, at least 30 wafer cassettes 22. The cassette storage can also be configured to store at least 40 wafer cassettes 22. This means that the cassette storage has at least 40 cassette storage locations 24. Typically, about 50 to 250 wafers are required to fill a wafer boat 58. Typically, about 25 wafers are provided in a wafer cassette 22. This means that typically, 2 to 10 wafer cassettes 22 are required to fill one wafer boat 58. By having at least 40 cassette storage locations 24, enough wafer cassettes 22 can be stored to fill at least two wafer boats 58, and particularly about four wafer boats. Thus, the loading and unloading of wafer cassettes 22 to and from the cassette operation space 12 can be extended for a significant period of time while the vertical batch furnace assembly 10 processes wafers from the wafer cassettes 22 housed in the cassette operation space 12.

[0024] In an embodiment, the wafer cassette 22 may be implemented as a Front Opening Unified Pod (FOUP). A FOUP is the industry standardized wafer cassette for wafers. The use of a FOUP is advantageous with respect to interchangeability of the wafer cassette 22 between the vertical batch furnace assembly 10 and other wafer processing machines.

[0025] In an embodiment, the vertical batch furnace assembly 10 may further comprise at least one cassette entry / exit port 42, 44 provided in the wall 16, 38, 40, 46 bounding the cassette operation space 12. This may be the first, second or third wall 16, 38, 40 already mentioned, but may also be a separate fourth wall 46. The cassette handling mechanism 26, 28 may be configured to further transport the wafer cassette 22 to and from the at least one cassette entry / exit port 42, 44. The at least one cassette entry / exit port 42, 44 may provide an entrance to and an exit from the vertical batch furnace assembly 10 for exchanging the wafer cassette 22 between the vertical batch furnace assembly 10 and the outside world, in particular a clean room environment.

[0026] The at least one cassette input / output port 42, 44 may include first and second input / output ports 42, 44 in a fourth wall 46 that may bound the cassette operating space 12 at an opposite end from the first wall 16. The first cassette input / output port 42 is reachable by the first cassette handler 26. The second cassette input / output port 44 is reachable by the second cassette handler 28.

[0027] By associating first and second cassette input / output ports 42, 44 with the first and second cassette handlers 26, 28, respectively, and thus with the first and second sets 30, 32 of cassette storage locations 24, a clear separation is provided within the cassette operation space 12. Each of the cassette handlers 26, 28 can have its own input / output ports 42, 44, and cassette storage locations 24. This means that they can operate independently of each other without having to wait for each other or get in each other's way. This can improve the efficiency of processing wafer cassettes 22 within the cassette operation space 12.

[0028] In an embodiment, the vertical batch furnace assembly 10 may include a storage rack 48 having at least some of the cassette storage locations 24. The storage rack 48 may have all of the cassette storage locations 24. The cassette operation space 12 is accessible through a closable maintenance opening, through which at least one storage rack 48 may be removed from the cassette operation space 12.

[0029] The storage rack 48 is essentially a rack of shelves on which the wafer cassettes 22 may be placed. It is a basic design with no moving parts. By placing the wafer cassettes 22 on the storage racks 48, sufficient cassette storage locations 24 may be created. When such storage racks 48 are removable from the cassette operation space 12, they may be easily removed, for example, by a hand truck or the like, when such removal is necessary or desirable. One or more storage racks 48 may be removed, for example, to provide easy access for service personnel to, for example, the first wall 16 where the cassette door opening device 54 may require maintenance. The cassette handler arm 34 of the second cassette handler 28 may be moved, for example, by the elevator mechanism 36, to an upper position, thus allowing service personnel to pass under the cassette handler arm 34. For example, by removing three storage racks 48 from the area holding the second set 32 ​​of cassette storage locations 24, easy access to the cassette door opening device 54 may be obtained.

[0030] In an embodiment, the vertical batch furnace assembly 10 may have a substantially rectangular footprint having two opposing short sides that define a width 50 of the vertical batch furnace assembly 10, and two opposing long sides that define a length 52 of the vertical batch furnace assembly 10. The width 50 of the vertical batch furnace assembly 10 may be 2.2 meters or less, or preferably, 1.7 meters or less. The length 52 of the vertical batch furnace assembly 10 may be 5 meters or less, preferably, 4 meters or less.

[0031] By having a substantially rectangular footprint, multiple vertical batch furnace assemblies 10 can be placed adjacent to one another to make optimal use of the available floor space. Adjacent vertical batch furnace assemblies 10 with a rectangular footprint should have no unused space between them. A width 50 of less than 2.2 meters is beneficial given compatibility with other vertical batch furnace assemblies, e.g., from other manufacturers / brands. A length 52 of 5 meters or less, preferably 4 meters or less, is beneficial for reducing the overall footprint.

[0032] In an embodiment, the vertical batch furnace assembly 10 may include a cassette door opening device 54. The cassette door opening device 54 may be located at or near the wafer transfer location 20. The cassette door opening device 54 may be located on the first wall 16. The cassette door opening device 54 may be configured to open the cassette door of a wafer cassette 22 located at the wafer transfer location 20. The cassette door opening device 54 may thus automatically open the cassette door of a wafer cassette 22 located at the wafer transfer location 20.

[0033] In an embodiment, the vertical batch furnace assembly 10 further comprises a wafer handler 56, a process chamber 60, and a wafer boat handling device located below the process chamber 60. The wafer handler 56 may be located within the wafer manipulation space 14 and may be configured to transfer wafers between the wafer cassettes 22 at the wafer transfer position 20 and a wafer boat 58. The process chamber 60 may be configured to process wafers contained in the wafer boat 58. The wafer boat handling device may be located adjacent to the wafer manipulation space 14. The wafer boat handling device may comprise the wafer boat 58 at the wafer boat transfer position and may be configured to transport the wafer boat 58 to the process chamber 60 and to the wafer boat transfer position.

[0034] When the wafer boat 58 is in the wafer boat transfer position, the wafer handler 56 can transfer unprocessed wafers from the wafer cassettes 22 in the wafer transfer position 20 to the wafer boat 58, and transfer processed wafers from the wafer boat 58 to the wafer cassettes 22 in the wafer transfer position 20. When the wafer boat 58 is loaded with one or more wafers, the wafer boat handling device can transport the loaded wafer boat 58 to a process chamber 60. In the process chamber 60, the wafers can be processed. After being processed, the wafer boat handling device can transport the processed wafer boat 58 back from the process chamber 60 to the wafer boat transfer position where the wafer handler 56 can transfer the processed wafer or wafers from the wafer boat 58 to the wafer cassette 22 at the wafer transfer position 20 and transfer unprocessed wafers from the wafer cassette 22 at the wafer transfer position 20 to the wafer boat 58, thus completing the batch process of the vertical batch furnace assembly 10.

[0035] In an embodiment, the first set 30 and the second set 32 ​​of the cassette storage locations 24 can be different. This means that the first set 30 and the second set 32 ​​of the cassette storage locations 24 are not equal sets and do not overlap. The first set 30 and the second set 32 ​​can be disjoint sets. Alternatively, they can also be overlapping sets. The advantage of being disjoint sets is that each cassette storage location 24 is associated with only one cassette handler 26, 28. This will minimize interference between the two cassette handlers 26, 28, which can increase the efficiency and reliability of the cassette handlers 26, 28 and reduce the chance of breakage.

[0036] In an embodiment, the cassette storage may comprise a rotatable cassette storage carousel having at least some of the cassette storage locations 24. The cassette storage carousel may comprise a central vertical support rotatable about a vertical carousel axis. The cassette storage carousel may also comprise several base stages connected to the central vertical support and having the cassette storage locations 24. The cassette storage carousel may further comprise a drive assembly that may be operatively connected to the central vertical support to rotate the central vertical support with the several base stages about the vertical carousel axis. Such a cassette storage carousel is an effective way to store wafer cassettes 22 in a limited space. Because the base stages are rotatable, the cassette storage carousel may rotate unused or unoccupied cassette storage locations 24 in the general direction of the associated cassette handler 26, 28. The cassette handler 26, 28 may thus always place the wafer cassette at the closest cassette storage location 24. The cassette handlers 26, 28 may therefore be sufficient with a smaller reach than would be necessary if the cassette handlers 26, 28 were to reach all of the cassette storage locations 24 by themselves.

[0037] Although exemplary embodiments of the present invention have been described above, in part with reference to the accompanying drawings, it should be understood that the present invention is not limited to these embodiments. From a study of the drawings, the disclosure, and the appended claims, those skilled in the art will be able to understand and effect variations to the disclosed embodiments in practicing the claimed invention.

[0038] Throughout this specification, a reference to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described with respect to that embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this description do not necessarily all refer to the same embodiment.

[0039] Furthermore, it should be noted that one or more specific features, structures, or characteristics of the various embodiments described above may be implemented independently of one another or may be combined in any suitable manner to form new, not expressly described, embodiments. The reference numbers used in the detailed description and claims do not limit the description of the embodiments, and do not limit the scope of the claims. The reference numbers are used for clarity only. [Explanation of symbols]

[0040] 10 Vertical batch furnace assembly 12 Cassette operation space 14 Wafer handling space 16 The First Wall 18 Wafer transfer opening 20 Wafer transfer position 22 Wafer Cassette 24 Cassette storage position 26 First Cassette Handler 28 Second Cassette Handler 30 First set (cassette storage position) 32 Second set (cassette storage position) 34 Cassette Handler Arm 36 Elevator Mechanism 38 The Second Wall 40 The Third Wall 42 First cassette input / output port 44 Second cassette input / output port 46 The Fourth Wall 48 Storage Rack 50 Width 52 Length 54 Cassette door opening device 56 Wafer Handler 58 Wafer Boat 60 Process Chamber

Claims

1. A vertical batch furnace assembly (10) for processing wafers, comprising: a cassette handling space (12), a wafer handling space (14), a first wall (16) separating the cassette operating space (12) from the wafer operating space (14) and having a single wafer transfer opening (18), in front of which, on the side of the first wall (16) directed towards the cassette operating space (12), a single wafer transfer position (20) for a wafer cassette (22) is provided in the cassette operating space (12); Equipped with The cassette operation space (12) is a cassette storage section having a plurality of cassette storage locations (24) and configured to store a plurality of wafer cassettes (22) each having a plurality of wafers; a cassette handling mechanism (26, 28) comprising a first cassette handler (26) configured to transfer wafer cassettes (22) between a first set (30) of cassette storage locations (24) and the single wafer transfer location (20), and a second cassette handler (28) configured to transfer wafer cassettes between a second set (32) of cassette storage locations (24) and the single wafer transfer location (20); A vertical batch furnace assembly (10).

2. 2. The vertical batch furnace assembly of claim 1, wherein the first and second cassette handlers (26, 28) each comprise a cassette handler arm (34) and an elevator mechanism (36) configured to reach wafer cassettes (22) positioned in cassette storage positions (24) at different vertical heights within the cassette handling space (12).

3. 3. The vertical batch furnace assembly of claim 2, wherein the elevator mechanism (36) of the first cassette handler (26) is disposed at or adjacent a second wall (38) and the elevator mechanism (36) of the second cassette handler (28) is disposed at or adjacent a third wall (40), the second and third walls (38, 40) bounding opposite ends of the cassette operation space (12).

4. 4. The vertical batch furnace assembly of claim 1, wherein the cassette storage is configured to store at least 30 wafer cassettes (22).

5. 5. The vertical batch furnace assembly of claim 1, wherein the cassette storage is configured to store at least 40 wafer cassettes (22).

6. 6. The vertical batch furnace assembly of claim 1, wherein the wafer cassette (22) is implemented as a front opening unified pod (FOUP).

7. 7. The vertical batch furnace assembly of claim 1, further comprising at least one cassette input / output port (42, 44) provided in a wall (16, 38, 40, 46) bounding said cassette operation space (12), said cassette handling mechanism (26, 28) configured to further transport wafer cassettes (22) to and from said at least one cassette input / output port (42, 44).

8. 8. The vertical batch furnace assembly of claim 7, wherein the at least one cassette entry / exit port (42, 44) comprises first and second cassette entry / exit ports (42, 44) in a fourth wall (46) bounding the cassette operation space (12) at an opposite end of the first wall (16), the first cassette entry / exit port (42) being accessible by the first cassette handler (26) and the second cassette entry / exit port (44) being accessible by the second cassette handler (28).

9. 9. The vertical batch furnace assembly of claim 1, further comprising a storage rack (48) including at least a portion of said cassette storage locations (24), said cassette operation space (12) being accessible through a closable maintenance opening, and at least one storage rack (48) being removable from said cassette operation space (12) through said maintenance opening.

10. 10. The vertical batch furnace assembly of claim 1, comprising a substantially rectangular footprint having two opposing short sides defining a width (50) of the vertical batch furnace assembly (10) and two opposing long sides defining a length (52) of the vertical batch furnace assembly (10), wherein the width (50) of the vertical batch furnace assembly (10) is 2.2 meters or less.

11. 11. The vertical batch furnace assembly of claim 10, wherein the width (50) of the vertical batch furnace assembly (10) is less than or equal to 1.7 meters.

12. 11. The vertical batch furnace assembly of claim 10, wherein the length (52) of the vertical batch furnace assembly (10) is less than or equal to 5 meters, preferably less than or equal to 4 meters.

13. With respect to the wafer transfer opening (18), the vertical batch furnace assembly (10) is a cassette door opening device (54) configured to open the cassette door of a wafer cassette (22) located in said single wafer transfer position (20); 13. The vertical batch furnace assembly of claim 1 , comprising:

14. The vertical batch furnace assembly (10) comprises: a wafer handler (56) arranged in said wafer handling space (14) and configured to transfer wafers between a wafer cassette (22) and a wafer boat (58) at said single wafer transfer location (20); a process chamber (60) configured to process the wafers contained in said wafer boat (58); a wafer boat handling device disposed below said process chamber (60) and adjacent to said wafer handling volume (14), said wafer boat handling device comprising said wafer boat (58) at a wafer boat transfer position and configured to transport said wafer boat (58) into said process chamber (60) and to said wafer boat transfer position; 14. The vertical batch furnace assembly of claim 1, further comprising:

15. 15. The vertical batch furnace assembly of claim 1, wherein said first and second sets (30, 32) of cassette storage locations (24) are different.

16. 16. The vertical batch furnace assembly of claim 1, wherein the cassette storage section comprises a rotatable cassette storage carousel having at least some of the cassette storage locations (24).

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