Wafer transfer method and wafer loading system

Abstract

Embodiments of the present invention provide a wafer transfer method and a wafer loading system. The method includes setting a wafer cassette at a loading port in an oven chamber. The wafer cassette contains one or more wafer boats carrying semiconductor wafers. The wafer boats are supported within the wafer cassette by wall grooves. Using a pusher, one or more wafer boats are transferred away from the wafer cassette and into a wafer cassette fixture positioned at the loading port. The transferred one or more wafer boats are supported within the wafer cassette fixture by wall grooves. During the transfer, one or more wafer boats are supported as they pass through the gap between the wafer cassette and the wafer cassette fixture via wall grooves of a bridge inserted between the wafer cassette and the wafer cassette fixture. After the transfer and use of a robot, the one or more wafer boats in the wafer cassette fixture are moved into the oven chamber.

Description

Technical Field

[0001] Embodiments of the present invention relate to wafer transfer methods and wafer loading systems. Background Technology

[0002] The following involves semiconductor manufacturing technology, semiconductor wafer processing technology, semiconductor processing furnace technology, and related technologies. Summary of the Invention

[0003] According to one aspect of an embodiment of the present invention, a wafer transfer method is provided for transferring a wafer to an oven chamber, the method comprising: setting a wafer cassette at a loading port of the oven chamber, the wafer cassette comprising one or more wafer boats carrying semiconductor wafers, wherein the wafer boats are supported in the wafer cassette by wall grooves of the wafer cassette; using push rods, transferring one or more wafer boats away from the wafer cassette and into a wafer cassette fixture disposed at the loading port, wherein the transferred one or more wafer boats are supported in the wafer cassette fixture by wall grooves of the wafer cassette fixture; supporting one or more wafer boats during transfer as they pass through the gap between the wafer cassette and the wafer cassette fixture via wall grooves of a bridge inserted between the wafer cassette and the wafer cassette fixture; and moving one or more wafer boats from the wafer cassette fixture into the oven chamber after transfer and use of a robot.

[0004] According to another aspect of an embodiment of the present invention, a wafer loading system is provided for loading a wafer boat stored in an associated wafer cassette into an associated oven chamber. The wafer loading system includes: a wafer cassette fixture; a loading port having a wafer cassette holder configured to hold the associated wafer cassette and a wafer cassette fixture holder configured to hold the wafer cassette fixture; a bidirectional push rod configured to push the wafer boat between the associated wafer cassette held in the wafer cassette holder and the wafer cassette fixture held in the wafer cassette fixture holder; and a bridge disposed in the gap between the wafer cassette holder and the wafer cassette fixture holder, and configured to support the wafer boat pushed between the associated wafer cassette held in the wafer cassette holder and the wafer cassette fixture held in the wafer cassette fixture holder.

[0005] According to another aspect of the present invention, a wafer transfer method is provided for transferring a wafer to an oven chamber. The wafer transfer method includes: disposing a wafer cassette at a loading port of the oven chamber, the wafer cassette including a wafer boat carrying a semiconductor wafer; pushing the wafer boat out of the wafer cassette and into a wafer cassette fixture disposed at the loading port; supporting the wafer boat during the pushing process as it passes through a gap between the wafer cassette and the wafer cassette fixture using a pontoon bridge; and moving the wafer boat from the wafer cassette fixture into the oven chamber. Attached Figure Description

[0006] The various aspects of the invention can be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with standard industrial practice, the various components are not drawn to scale and are for illustrative purposes only. In fact, for clarity of discussion, the dimensions of the various components may be arbitrarily increased or decreased.

[0007] Figure 1 and Figure 2 Different perspective views of the loading ports used for transferring wafers to and from the oven chamber are schematically shown.

[0008] Figure 3 schematically shown Figure 1 and Figure 2 An enlarged view of the loading port portion, including two wafer transfer subassemblies, one of which has a wafer cassette located in its wafer cassette holder while the other does not.

[0009] Figure 4 The illustration shows what is suitable for and Figure 1 and Figure 2 A perspective view of the loading port combined with the wafer cassette and wafer cassette fixture, and the pontoon bridge inserted therebetween.

[0010] Figure 5 schematically shown Figure 3 Perspective view of the wafer box fixture and pontoon bridge.

[0011] Figure 6 The illustration shows what is suitable for and Figure 1 and Figure 2 A side view of the loading port combined with the wafer cassette, wafer cassette fixture, and inserted pontoon.

[0012] Figure 7 The illustration shows what is suitable for and Figure 1 and Figure 2 A side view of the pontoon bridge used in conjunction with the loading port.

[0013] Figure 8 A flowchart is shown of a thermal processing method performed using an oven chamber and its loading port. Detailed Implementation

[0014] The following disclosure provides numerous different embodiments or examples for implementing various features of the invention. Specific embodiments or examples of components and arrangements are described below to simplify the invention. Of course, these are merely examples and not intended to be limiting. For example, in the following description, forming a first component above or on a second component can include embodiments where the first and second components are in direct contact, and can also include embodiments where an additional component can be formed between the first and second components, such that the first and second components are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0015] Furthermore, for ease of description, this document may use spacing terms such as “below,” “under,” “lower,” “above,” “upper,” etc., to describe the relationship between one element or component and another, as shown in the figures. In addition to the orientations shown in the figures, spacing terms are intended to include different orientations of the device during use or operation. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spacing descriptors used herein may be interpreted accordingly.

[0016] In semiconductor manufacturing facilities, automated transport systems, such as Automated Material Handling Systems (AMHS), are used to move batches of semiconductor wafers through the facility. These automated transport systems may include, for example, overhead transport (OHT) trolleys for moving semiconductor wafers in batches between different processing tools along a predetermined workflow. As a non-limiting illustrative example, various processing tools may include lithography systems, deposition systems, etching systems, etc.

[0017] Some processing tools include ovens for thermally processing semiconductor wafers, such as those used for annealing, thermal oxidation in an environment containing oxygen and / or oxygen-containing substances, post-exposure baking (PEB) as part of photolithography processes, and dopant diffusion. Processing at high temperatures can increase the likelihood of semiconductor wafer contamination due to degassing from heated materials. Furthermore, high temperatures pose safety hazards to personnel in manufacturing facilities, such as fire or explosion hazards (when thermal processing is performed in a flammable environment).

[0018] To address these challenges while maintaining high wafer throughput, wafer handling—specifically, automated wafer transfer components—is used for loading / unloading batches of semiconductor wafers into and out of the oven chamber. Notably, the semiconductor wafers are placed on boats made of materials such as quartz and silicon carbide, which can withstand the high temperatures within the oven chamber without causing unacceptable degassing. Multi-axis robots are used to move wafers in and out of the oven chamber, improving wafer production efficiency, reducing the likelihood of wafer contamination, and minimizing the risk of worker burns.

[0019] While such methods are beneficial, proper wafer handling during oven loading / unloading remains challenging, especially as semiconductor wafer sizes continue to increase. For example, heating and cooling of the semiconductor wafer and / or supporting boat can cause wafer and / or boat warping, which can interfere with automated wafer handling.

[0020] This article discloses an improved wafer transfer method for transferring wafers to an oven chamber, and an improved wafer loading system for loading a wafer boat stored in a wafer cassette into the oven chamber.

[0021] It is noteworthy that, in the embodiments disclosed herein, the wafer is transferred to a loading port of an oven within a wafer cassette arranged on a wafer boat. In the embodiments disclosed herein, the wafer boat is planar and horizontally oriented. The loading port includes mechanisms for transferring the wafer boat from the wafer cassette to a wafer cassette fixture that can be placed into the oven. During the transfer of the wafer boat, a gap exists between the wafer cassette and the wafer cassette fixture. This gap relaxes the positioning accuracy tolerances of the wafer cassette and the wafer cassette fixture at the loading port; however, the gap can cause problems because sagging or warping can lead to unreliable transfer of the wafer boat between the wafer cassette and the wafer cassette fixture. As disclosed herein, during the transfer of the wafer boat, a bridge is positioned between the wafer cassette and the wafer cassette fixture. The bridge provides support for the wafer boat in the gap. Furthermore, the wall grooves of the bridge supporting the wafer boat in the gap may have unfolded ends that further guide the transfer of the wafer boat.

[0022] refer to Figure 1 and Figure 2The furnace or oven 10 includes one or more furnace or oven chambers 12 and corresponding loading ports 14. The terms "furnace" and "oven" are used interchangeably herein and are used for the more typical use of "oven" and "oven chamber". The oven 10 is used to thermally process semiconductor wafers. Thermal processing may include annealing, thermal oxidation (e.g., to form thermal oxides on a semiconductor wafer or layer), post-exposure baking (PEB) as part of a photolithography process, thermally driven dopant diffusion, deposition containing molecules that bond to the surface of the semiconductor wafer or layer at the temperature established by the oven 10, etc. The oven 10 controls the temperature within the oven chamber 12 to a temperature suitable for the specific thermal processing being performed, such as the range of 700°C to 1300°C for some thermal oxidation processes for silicon oxide, the range of 800°C to 1500°C or higher for some dopant diffusion processes, the range of 50°C to 150°C for some PEB processes, etc. These are merely non-limiting examples. Furthermore, the oven 10 may optionally include a programmable electronic controller for executing the thermal cycling recipe. By way of non-limiting illustration, the thermal cycle may begin at a low temperature during wafer loading, ramp up to the dwell temperature at a programmed ramp rate (e.g., specified in degrees / minute), hold at the dwell temperature for a fixed time interval, and then ramp down to a lower unloading temperature at a programmed descent rate. Although in Figure 1 and Figure 2 Not shown, but oven 10 may optionally include conduits for supplying a controlled environment within oven chamber 12 during thermal processing, such as an oxygen atmosphere, a humid oxygen atmosphere (e.g., by passing oxygen through a bubbler), a syngas atmosphere (e.g., a mixture of hydrogen and nitrogen), an atmosphere containing dopant precursors for dopant diffusion processes, etc. When a controlled atmosphere is provided, a programmable electronic controller (if provided) can execute a flow cycle formulation simultaneously with the thermal cycle formulation, such that, for example, “active” gases (e.g., oxygen during oxidation, gases containing dopant precursors during dopant diffusion processes, etc.) are present only during the residence time of the thermal cycle.

[0023] On the other hand, in some embodiments, the oven 10 may include little or no complex electronic equipment. For example, the oven 10 may include a single temperature setpoint control for setting the temperature in the oven chamber 12 to a fixed constant temperature, and optional gas inlets and exhaust or outlets for providing an environment.

[0024] Semiconductor wafers placed on the wafer boat are transported individually or (more commonly) in batches to loading port 14 and stored in wafer cassettes 20. Wafer cassettes 20 are transported to loading port 14 via an automated material handling system (AMHS) 21, only when... Figure 1Or some other robotic transport system, schematically illustrated. For example, AMHS 21 may include an overhead transport (OHT) system comprising a multi-branch overhead track system having branches leading to loading port 14, a carrier or pod carrying wafer cassettes that travels along the track system, and a loading port for automatically transferring the wafer cassettes from the carrier or pod to loading port 14, which includes the illustrative oven 10. Although in Figure 1 Not shown, but after the wafer contained in the delivery wafer cassette 20 has been thermally processed using oven 10, AMHS 21 appropriately retrieves the wafer cassette 20 according to the designed integrated circuit (IC) manufacturing workflow, and can then transport it to the next processing tool in the manufacturing facility. While AMHS systems are common in large semiconductor manufacturing facilities, in the anticipated alternative manual method, the wafer cassette can be transported manually, for example by manufacturing facility workers, to loading port 14.

[0025] Continue to refer to Figure 1 and Figure 2 And further reference Figure 3 Loading port 14 includes a desktop with one or more wafer transfer sub-assemblies. Two such wafer transfer sub-assemblies are located in... Figure 3 The image is shown in an enlarged view. Each wafer transfer subassembly includes a wafer cassette holder 22 configured to hold a wafer cassette 20 transferred by AMHS 21, a wafer cassette holder 26 configured to hold a wafer cassette jig 26, and bidirectional pushers. The bidirectional pushers include a first pusher 30 and a second pusher 32. The first pusher 30 is arranged to push a wafer boat (on which a semiconductor wafer is disposed) out of the wafer cassette 20 and into the wafer cassette jig 26, and the second pusher 32 is arranged to push a semiconductor wafer out of the wafer cassette jig 26 and into the wafer cassette 20. Note that... Figures 1-3 Each of them has a wafer transfer sub-assembly, so that the wafer cassette 22 is exposed for the wafer transfer sub-assembly. No wafer cassette is placed in any of them, therefore the wafer cassette 22 is exposed for that wafer transfer sub-assembly. Figures 1-3 All wafer transfer subassemblies have a seated wafer cassette holder 26, therefore an example of a wafer cassette holder base is not shown, but it can be understood to be located below and providing a seat for the shown seated wafer cassette holder 26. Generally, the wafer cassette holder 22 includes components that mate with corresponding components of the wafer cassette 20 to prevent the seated wafer cassette 20 from sliding or otherwise moving across the tabletop. For example, the wafer cassette holder 22 may include upwardly extending pins that engage with openings in the bottom of the wafer cassette 20, and vice versa. Similarly, the wafer cassette holder base includes components that mate with corresponding components of the wafer cassette holder 26 to prevent the seated wafer cassette holder 26 from sliding or otherwise moving across the tabletop.

[0026] Therefore, AMHS 21 transports the wafer cassette 20 to the loading port 14 and places it in the wafer cassette holder 22, opposite the corresponding in-place wafer cassette fixture 26. The first push rod 30 is motorized and includes a mating surface 31 (only when...). Figure 3 (The wafer is) moved towards and into wafer cassette 20 (e.g., in...) Figure 3 (Looking to the right in the perspective view) to engage and push the wafer boat (with the semiconductor wafer) contained in the wafer cassette 20 away from the wafer cassette 20. The end of the wafer cassette 20 is directed toward the in-place wafer cassette clamp 26 of the wafer transfer subassembly, and the wafer boat continues to be pushed until it is pushed into the in-place wafer cassette clamp 26. Then the first push rod 30 retracts. (Note that...) Figures 1-3 (This shows all pushers in their respective fully retracted positions).

[0027] It is worth noting that while this process can be used to transfer a single boat carrying as few as a single semiconductor wafer, more typically, wafer cassette 20 carries multiple boats with correspondingly multiple semiconductor wafers to achieve high wafer throughput, such as five, ten, fifteen, twenty or more boats as some non-limiting illustrative examples. To handle multiple boats, the engagement surface 31 of the first pusher 30 appropriately has an extended contact area sufficient to engage and push all the boats in wafer cassette 20 to transfer them from wafer cassette 20 to wafer cassette fixture 26. For simplicity, multiple boats carrying multiple semiconductor wafers are referred to herein as examples. Furthermore, since placing boats not carrying semiconductor wafers into oven 10 is generally not useful (because the goal is to perform thermal processing on the semiconductor wafers, not the boats), it is sometimes not described here. For simplicity, boats typically carry semiconductor wafers.

[0028] Special return to reference Figure 1 and Figure 2After the wafer boat is transferred from the wafer cassette 20 to the wafer cassette fixture 26 using the first pusher 30 described above, a multi-axis robot 40 automatically moves the wafer boat from the wafer cassette fixture 26 into the oven chamber 12. An exemplary multi-axis robot 40 is a six-axis robot; however, other articulated robots may be employed as appropriate to provide the necessary articulation flexibility to perform the transfer. The robot 40 includes a gripping assembly 42, which is shaped and sized to engage the wafer cassette fixture 26 and lift it away from the loading port 14 and transfer it to the oven chamber 12. The gripping assembly 42 may be a passive assembly, such as having a groove that engages with a lip or similar feature of the wafer cassette fixture 26; or the gripping assembly 42 may be an active assembly with an electrically powered gripper that approaches the wafer cassette fixture 26 to grip it. In some embodiments, the multi-axis robot 40 places the entire assembly (i.e., the wafer boat contained in the wafer cassette fixture 26) into the oven chamber 12. Alternatively, the clamping assembly 42 may include push rods (e.g., similar to first and second push rods 30, 32) to push the wafer boat contained in the wafer cassette clamp 26 into a receiving slot in the oven chamber 12. In an exemplary embodiment, it is assumed that the robot 40 places the entire assembly including the wafer cassette clamp 26 into the oven chamber 12.

[0029] After a boat carrying a semiconductor wafer is placed in an oven chamber 12, the semiconductor wafer is subjected to the desired thermal processing using the oven chamber 12. In some embodiments, the oven chamber 12 is maintained at a constant temperature and the thermal processing is performed during time intervals in which the semiconductor wafer remains in the oven chamber 12. In other embodiments, the oven 10 includes a programmable electronic controller (not shown) that executes thermal cycling recipes and / or processes to perform more complex and / or tightly controlled thermal processing. As previously described, as a non-limiting illustrative example, thermal processing may include annealing, thermal oxidation, post-exposure baking (PEB) as part of a photolithography process, dopant diffusion, material deposition, and various combinations thereof.

[0030] After thermal processing is complete, the process is essentially reversed to unload the wafer carrier holding the semiconductor wafers. Robot 40 uses its gripping assembly 42 to pick up the wafer cassette fixture 26 and place it back onto the wafer cassette fixture holder at the loading port 14, which is opposite the corresponding in-place wafer cassette 20. The second pusher 32 is motorized and includes a mating surface 33 (only on...). Figure 3 The wafer (out of the bid) moves toward and into the wafer cassette fixture 26 (e.g., in...). Figure 3 (From the perspective view to the left), the wafer cassette jig 26 is moved from the end of the wafer cassette jig 26 facing the wafer transfer subassembly to engage and push the contained wafer boat (with the thermally processed semiconductor wafer) into place in the wafer cassette 20, and the wafer boat is pushed until it is pushed into place in the wafer cassette 20. Then the second pusher 30 retracts. (Note again,) Figures 1-3This shows all pushers in their respective fully retracted positions. Afterwards, AMHS21 (see...) Figure 1 The wafer cassette fixture 20 is removed from loading port 14 and typically moved into a carrier or pod of AMHS 21 for transport to the next processing tool in the integrated circuit (IC) manufacturing workflow.

[0031] Continue to refer to Figure 3 And further reference Figure 4 , Figure 4 The image shows the in-place wafer cassette fixture 20 and in-place wafer cassette fixture 26 for the separated wafer transfer sub-assemblies. In some non-limiting illustrative embodiments, the gap G between the wafer cassette 20 and the wafer cassette fixture 26 is greater than or equal to 0.1 mm and less than or equal to 20 mm, although other values ​​are considered.

[0032] Figure 5 A portion of the wafer cassette jig 26 is shown, close to the wafer cassettes in their respective positions, and the wafer boat 50 being transferred to (or from) the wafer cassette jig 26. Figure 5 A batch of 10 crystal boats 50 is shown; however, as previously stated, the number of crystal boats transferred can be one, two, three, five, ten, more, or essentially any number. Figure 5 As shown, the boat 50 is typically planar, i.e., has a shape factor such as a flat plate, and is positioned horizontally. Therefore, downward gravity acts on the boat 50 as it passes through the gap G. This causes the boat to sag as it passes through the gap G due to a lack of bottom support. Additionally, the semiconductor wafers (not shown) on the boat 50 may exhibit some warping due to the net compressive or tensile strain introduced by the material layers deposited on the wafers. Furthermore, varying thermal expansion can cause warping of the boat and / or the semiconductor wafers.

[0033] Furthermore, to maximize wafer yield, for a given wafer cassette 20, it is generally desirable to load as many wafer boats 50 as possible into the wafer cassette 20 (and therefore into the wafer cassette fixture 26). This results in adjacent wafer boats 50 (in... Figure 5 The vertical spacing ΔH between the two sides (represented in the middle) is advantageously made as small as possible.

[0034] Figure 6 A side cross-sectional view of the wafer cassette 20 and wafer cassette fixture 26 of the wafer transfer sub-assembly is shown. Figure 6 As shown, the wafer cassette 20 has a wall groove 52, and similarly, the wafer cassette fixture 26 has a wall groove 54 that is perpendicularly aligned with the wall groove 52 of the facing wafer cassette 20. Note Figure 6 The side cross-sectional view is enlarged and only shows three wall slots 52 and three wall slots 54. (Return to Reference) Figure 5The horizontally oriented wafer boats 50 are supported by their edges when they are located in the wall slots 54 of the wafer cassette 26. Similarly (although not shown), when the wafer boats 50 are in the wafer cassette 20, they are supported by their edges in the wall slots 52 of the wafer cassette 20. Note that Figure 6 A single crystal boat 50 is schematically shown, however... Figure 5 As shown, a wafer boat can typically be supported by each wall slot 52 of the wafer cassette 20 or each wall slot 54 of the wafer cassette fixture 26.

[0035] The arrangement in which the wafer boat 50 is supported within the wafer cassette 20 by engaging its edges into the wall groove 52 or its edges into the wall groove 54 of the wafer cassette clamp 26 has significant advantages. First, it leaves most of the interior of the wafer cassette 20 open and hollow (as is the case with the wafer cassette clamp 26), which allows the corresponding first and second push rods 30 and 32 (see...) to be supported. Figure 3 The vertically extending surfaces 31 and 33 of the wafer cassette 20 are fitted and pass through the central opening of the wafer cassette 20 and the central opening of the wafer cassette clamp 26, and are supported by their edges disposed in the respective wall grooves 52, 54. When having a central opening, the wafer cassette 20 may optionally have a closed end away from the end facing the wafer cassette clamp 26. Similarly, although having a central opening, the wafer cassette clamp 26 may optionally have a closed end away from the end facing the wafer cassette 20.

[0036] A second advantage of this arrangement, where the crystal boat 50 is supported by its edges, is that by contacting the wafer only through the edges of the crystal boat 50, the likelihood of contamination of the semiconductor wafer on the crystal boat 50 is reduced. Conversely, if the crystal boat glides across a larger surface area, this would generate airborne particles that could contaminate the surface of the semiconductor wafer set on the crystal boat 50.

[0037] A third advantage of this arrangement in which the crystal boats 50 are supported by their edges is that this edge-supported arrangement can accommodate the thermal expansion of the crystal boats 50 due to heating in the oven chamber 12, and also provides a limited heat conduction path for heat transfer.

[0038] The gap G between the in-place wafer cassette 20 and the in-place wafer cassette fixture 26 of the wafer transfer sub-assembly (in Figure 3 , Figure 4 and Figure 6The gap G (as indicated in the diagram) advantageously relaxes the precision tolerances for AMHS 21 and robot 40 to place wafer cassette 20 and wafer cassette fixture 26 onto loading port 14, respectively. However, the gap G introduces some problems. For example, due to lattice mismatch in semiconductor wafers with epitaxial mismatched epitaxial layers, different thermal expansion, stress or strain caused by expansion during heating, the boat 50 and / or the semiconductor wafer it carries may warp; due to gravity during transfer across the gap G, the boat 50 and / or the semiconductor wafer it carries may sag, or a combination of such effects may occur. This can lead to unreliable transfer of the boat 50 between wafer cassette 20 and wafer cassette fixture 26. During loading, the boat exiting the wall slot 52 of wafer cassette 20 may not align and engage with the corresponding wall slot 54 of wafer cassette fixture 26. Similarly, during unloading, the boat exiting the wall slot 54 of wafer cassette fixture 26 may not align and engage with the corresponding wall slot 52 of wafer cassette 20. The small spacing ΔH between vertically adjacent crystal boats 50 is to maximize the number of crystal boats 50 in the wafer cassette 20 and to provide edge support for the crystal boats 50 in the wall grooves 52 and / or 54, which increases the possibility of unreliable transfer of the crystal boats 50 between the wafer cassette 20 and the wafer cassette fixture 26.

[0039] To solve this problem, refer to Figures 1-6 And specifically refer to Figures 3-6 The pontoon bridge 60 is inserted between the positioned wafer cassette 20 and the positioned wafer cassette fixture 26. Equivalently, it can be said that the pontoon bridge 60 is clamped between the wafer cassette holder 22 and the wafer cassette fixture holder. Figure 5 and Figure 6 As seen in the diagram, the pontoon bridge 60 includes a wall groove 62, such as... Figure 6 As shown in the optimal configuration, the wall groove 52 of the in-place wafer cassette 20 is aligned with the wall groove 54 of the in-place wafer. Therefore, as the wafer boats 50 are transferred between the in-place wafer cassette 20 and the in-place wafer cassette jig 26, they are supported in the gap G by the wall groove 62 of the bridge 60. Like the wafer cassette 20 and the wafer cassette jig 26, the bridge 60 is hollow and has an open central aperture through which the wafer boats pass, while being supported in the wall groove 62 by their edges.

[0040] Return to reference Figure 3 In some embodiments, the pontoon 60 of each wafer transfer sub-assembly retracts into the recess of the loading port 14 of the oven 10 when not in use. Figure 3 A pontoon bridge 60 rising from a recess is shown, as well as another pontoon bridge 60 retracting into a recess of the loading port 14. RIn some embodiments, this can be performed automatically as follows: After the AMHS 21 sets the wafer cassette 20 on the loading port 14 (i.e., into the wafer cassette holder 22), before transfer, an actuating motor, pneumatic cylinder, or hydraulic cylinder, etc., is used to raise the bridge 60 to an operating position at least partially outside the recess of its loading port 14, aligning its wall groove 62 with the wall grooves 52, 54 of the corresponding wafer cassette 20 and wafer cassette holder 26. In a suitable method, the wafer cassette holder 22 includes an upwardly extending plunger that is pressed down by the wafer cassette 20 when it is positioned in the wafer cassette holder 22, and the pressing down of the plunger generates an actuation signal that triggers the lifting of the wafer bridge 60. Conversely, when the wafer cassette 20 is removed from the wafer cassette holder 22, the plunger springs back, thereby providing an actuation signal for lowering the wafer bridge 60 back into the recess of the loading port 14.

[0041] The arrangement of the pontoon 60 stored in the recess of the loading port 14 when not in use has several advantages. It provides a more compact and reduced profile for the loading port 14. It also allows the height of the pontoon 60 to be adjusted to precisely align the wall slots 62 of the pontoon 60 with the corresponding wall slots 52, 54 of the in-place wafer cassette 20 and the in-place wafer cassette clamp 26. This can be done manually, or in variant embodiments, using optical sensors—for example, the pontoon 60 can be raised until a laser beam passes through all the wall slots 52, 54, 62 and strikes a photodetector to indicate alignment.

[0042] On the other hand, in some embodiments, the pontoon 60 does not rise and retract into the recess of the loading port 14. Instead, in these embodiments, the pontoon 60 is stationary and always at the appropriate height so that the wall groove 62 of the pontoon 60 is aligned with the wall grooves 52, 54 of the corresponding wafer cassette 20 and wafer cassette clamp 26.

[0043] refer to Figure 5 and Figure 6 And further reference Figure 7 In addition to providing support for the crystal boat 50 as it passes through the gap G, the pontoon bridge 60 may optionally provide guidance for the crystal boat 50. For this purpose, an exemplary wall groove 62 of the pontoon bridge 60 has an outwardly flared end 62. E If the crystal boat 50 approaches the bridge 60 and the warping of the crystal boat 50 is sufficient to cause it to miss the alignment slot 62 of the bridge 60, then the end 62 is deployed. E Operable to guide the warped boat bridge to a cam-action alignment groove 62 through the surface of the unfolded end 62E, the cam action pushing the edge of the warped boat 50 downward (in the case of the boat warping upward) or upward (in the case of the boat warping downward) so as to slide into the alignment groove 62.

[0044] In some non-limiting illustrative embodiments, the outwardly extending end 62E The expansion angle θ 展开 The angle is 60 degrees or less, but larger unfolding angles are also conceivable. Larger unfolding angles reduce the effectiveness of the cam action because it approaches a vertical wall towards the edge of the incoming crystal boat. In some non-limiting illustrative embodiments, the outwardly unfolding end 62... E The expansion angle θ 展开 The angle should be at least 15 degrees. Smaller unfolding angles reduce the vertical extent of the outward unfolding, which can prevent the warped boat from reaching the outward unfolding end. For example... Figure 7 As shown, the outwardly extending end can be equivalently quantified by the indicated angle θ2, where θ2 = 180° - θ 展开 .

[0045] Figure 6 and Figure 7 A side cross-sectional view of the wall groove 62 of the pontoon bridge 60 is shown, which shows the outwardly extending end 62 extending outward in the vertical direction. E The unfolding angle θ 展开 (Or equivalently, θ2) refers to outward expansion in the vertical direction. For example... Figure 5 As shown in the perspective view, the outwardly extending end 62 E Alternatively, it can be deployed outward in a horizontal direction. This horizontal deployment can guide the crystal boat 50 into the pontoon bridge 60 if the crystal boat 50 is laterally offset from the opening of the pontoon bridge 60.

[0046] Special Reference Figure 6 The ends of the wall groove 52 of the wafer cassette 20 and / or the ends of the wall groove 54 of the wafer cassette clamp 26 may optionally have outwardly flared ends. Figure 6 In the wafer cassette 20, the outwardly extending end of the wall groove 52 has an angle θ1, and the outwardly extending end of the wall groove 54 of the wafer cassette fixture 26 has as follows: Figure 6 The angle θ3 is shown. In a non-limiting exemplary embodiment, θ1 = θ3 and θ1 > θ2 and θ3 > θ2. In some such embodiments, θ2 ≥ 120°. In some embodiments, the wall groove 52 of the wafer cassette 20 and / or the wall groove 54 of the wafer cassette clamp 26 have outwardly flared ends with a flared angle smaller than the flared angle of the outwardly flared ends of the wall groove of the pontoon bridge. In some embodiments, the wall groove 52 of the wafer cassette 20 and / or the wall groove 54 of the wafer cassette clamp 26 do not have outwardly flared ends. These are merely illustrative examples. Furthermore, although not shown, it is conceivable that the ends of the wall groove 52 of the wafer cassette 20 and / or the wall groove 54 of the wafer cassette clamp 26 may also optionally have outwardly flared ends that flare outward in the horizontal direction.

[0047] refer to Figure 8This describes an illustrative method for transferring wafers to and from oven chamber 12 using a pontoon bridge 60. In operation 70, a wafer cassette 20 is positioned on the loading port 14 of oven chamber 12, i.e., the wafer cassette 20 is located in wafer cassette holder 22. This can be accomplished, for example, by an AMHS 21 (see...). Figure 1 In operation 72, the recessed pontoon bridge 60 R It is raised from the recess in the loading port 14 to its raised position by a motor, hydraulic cylinder, pneumatic cylinder or other power mechanism (see...). Figure 3 (and related discussions). Operation 72 can be triggered, for example, by placing the wafer cassette 20 onto the wafer cassette holder 22, pressing a button, or otherwise activating an actuator that generates a control signal to trigger a motor, cylinder, etc., to lift the pontoon. In embodiments where the pontoon bridge 60 does not have a rise / recess, operation 72 is appropriately omitted.

[0048] In operation 74, the first pusher 30 is operated to transfer the wafer boat 50 (typically loaded with semiconductor wafers) from the placed wafer cassette 20 via the pontoon bridge 60 into the wafer cassette fixture 26. In operation 76, the multi-axis robot 40 is operated (e.g., programmed to) transport the wafer cassette fixture 26 with the wafer boat from the loading port 14 into the oven chamber 12 (see [link to relevant documentation]). Figure 1 and Figure 2 (and related discussions). In some embodiments, the entire unit, including wafer cassette clamp 26 and a wafer boat 50 therein loaded with semiconductor wafers, is placed into the oven chamber 12 by a robot 40. In this case, the wafer cassette clamp 26 is suitably made of a material that can withstand the high temperatures and environment of the oven chamber 12 without decomposition or unacceptable degassing. In other embodiments, the clamping assembly 42 includes push rods (e.g., similar to push rods 30, 32) to push the wafer boat 50 out of the wafer cassette clamp 26 and into the oven chamber 12, supported, for example, by wall grooves or flat surfaces (details not shown) in the oven chamber 12.

[0049] In operation 78, oven 10 is used to perform thermal processing on the semiconductor wafer loaded into oven chamber 12 in operation 76. As previously described, thermal processing may include, but is not limited to, illustrative example annealing, thermal oxidation, PEB as part of a photolithography process, dopant diffusion, material deposition, various combinations thereof, etc., and may involve pre-programmed temperature rise / dwell / fall, circulation of ambient gas components, and / or ambient pressure, etc.

[0050] In operation 80, after thermal processing 78 is completed, the robot 40 is operated (e.g., pre-programmed) to pull the wafer cassette jig 26 out of the oven chamber 12 and place it back onto the wafer cassette jig holder. (In a variant embodiment where only the wafer boat is inserted into the oven chamber, operation 80 initially requires the use of a pull arm or other mechanism integrated into the gripping assembly 42 to retrieve the wafer boat back into the wafer cassette jig). In operation 82, the second pusher 32 is operated to transfer the wafer boat 50, on which the semiconductor wafers (now thermally processed) are loaded, from the in-place wafer cassette jig 26, across the pontoon bridge 60, and back into the in-place wafer cassette 20. In operation 84, the wafer cassette 20 is again removed from the loading port 14 by the AMHS 21, for example, from the loading port 14.

[0051] If operation 72 is performed to raise the pontoon 60 from the recess in the loading port 14, then in operation 86, the pontoon 60 retracts back into the recess in the loading port 14 by operation of a motor, hydraulic cylinder, pneumatic cylinder, or other power mechanism. Operation 86 can be triggered, for example, by removing the wafer cassette 20 from the wafer cassette holder 22 and releasing a button or other actuator that triggered operation 72. In embodiments where operation 72 is omitted, operation 86 is thus also omitted.

[0052] Further embodiments are described below.

[0053] In a non-limiting illustrative embodiment, a wafer transfer method is disclosed for transferring wafers to an oven chamber. A wafer cassette is disposed at a loading port of the oven chamber. The wafer cassette contains one or more wafer boats carrying semiconductor wafers. The wafer boats are supported within the wafer cassette by wall grooves in the wafer cassette. Using a pusher, one or more wafer boats are transferred away from the wafer cassette and into a wafer cassette fixture disposed at the loading port. The transferred one or more wafer boats are supported within the wafer cassette fixture by wall grooves in the wafer cassette fixture. The transfer includes supporting one or more wafer boats as they pass through the gap between the wafer cassette and the wafer cassette fixture via wall grooves of a bridge inserted between the wafer cassette and the wafer cassette fixture. After the transfer and using a robot, one or more wafer boats in the wafer cassette fixture are moved into the oven chamber.

[0054] In some embodiments, the method further includes: after placing the wafer cassette on the loading port of the oven chamber and before transfer, operating a motor or pneumatic or hydraulic cylinder to lift the pontoon at least partially out of the recess of the loading port.

[0055] In some embodiments, the method further includes: using a second pusher to transfer one or more wafer boats a second time away from the wafer cassette fixture and into the wafer cassette, wherein the transferred one or more wafer boats are supported in the wafer cassette by wall grooves in the wafer cassette; supporting one or more wafer boats during the second transfer as they pass through the gap between the wafer cassette and the wafer cassette fixture via wall grooves of a bridge inserted between the wafer cassette and the wafer cassette fixture; and removing the wafer cassette from the loading port of the oven chamber.

[0056] In some embodiments, the wall groove of the wafer cassette is vertically aligned with the corresponding wall groove of the wafer cassette fixture, and the wall groove of the wafer cassette is vertically aligned with the corresponding wall groove of the pontoon bridge.

[0057] In some embodiments, the wall grooves of the pontoon bridge have outwardly flared ends.

[0058] In some embodiments, the outwardly extending end has an extension angle of 60 degrees or less.

[0059] In some embodiments, the wall groove of the wafer cassette and the wall groove of the wafer cassette fixture do not have outwardly flared ends or have outwardly flared ends, and the flare angle of the outwardly flared ends is smaller than the flare angle of the outwardly flared ends of the wall groove of the pontoon bridge.

[0060] In some embodiments, the gap between the wafer cassette and the wafer cassette fixture is greater than or equal to 0.1 mm and less than or equal to 20 mm.

[0061] In a non-limiting illustrative embodiment, a wafer loading system is disclosed for loading a wafer boat stored in an associated wafer cassette into an associated oven chamber. The wafer loading system includes a wafer cassette fixture, a loading port, a bidirectional pusher, and a pontoon. The loading port has a wafer cassette holder configured to hold the associated wafer cassette and a wafer cassette fixture holder configured to hold the wafer cassette fixture. The bidirectional pusher is configured to push the wafer boat between the associated wafer cassette in the wafer cassette holder and the wafer cassette fixture in the wafer cassette fixture holder. The pontoon is disposed in the gap between the wafer cassette holder and the wafer cassette fixture holder and configured to support the wafer boat pushed between the associated wafer cassette in the wafer cassette holder and the wafer cassette fixture in the wafer cassette fixture holder.

[0062] In some embodiments, the associated wafer cassette has a wall groove for supporting a wafer boat stored in the associated wafer cassette; the wafer cassette fixture has a wall groove for supporting a wafer boat in the wafer cassette fixture; and the pontoon bridge has a wall groove for supporting a wafer boat pushed between the associated wafer cassette disposed in the wafer cassette holder and the wafer cassette fixture disposed in the wafer cassette fixture holder.

[0063] In some embodiments, the wall grooves of an associated wafer cassette disposed in a wafer cassette holder and the wall grooves of a wafer cassette fixture disposed in a wafer cassette fixture holder are aligned with each other.

[0064] In some embodiments, the wafer loading system further includes a motor, pneumatic cylinder, or hydraulic cylinder operably connected to lift the pontoon from the recess of the loading port to a position where the wall groove of the pontoon aligns with the wall groove of an associated wafer cassette disposed in a wafer cassette holder and the wall groove of a wafer cassette fixture disposed in a wafer cassette fixture holder.

[0065] In some embodiments, the wall grooves of the pontoon bridge have outwardly flared ends.

[0066] In some embodiments, the outwardly extending end has an extension angle of 60 degrees or less.

[0067] In some embodiments, the wall groove of the wafer cassette and the wall groove of the wafer cassette fixture do not have outwardly flared ends or have outwardly flared ends, and the flare angle of the outwardly flared ends is smaller than the flare angle of the outwardly flared ends of the wall groove of the pontoon bridge.

[0068] In some embodiments, the wafer loading system further includes a multi-axis robot configured to remove the wafer cassette fixture from the wafer cassette fixture holder at the loading port and transfer the wafer boat in the wafer cassette fixture to the associated oven chamber.

[0069] In some embodiments, the wafer loading system further includes a multi-axis robot configured to transfer a wafer cassette fixture from a wafer cassette fixture holder at the loading port into an associated oven chamber.

[0070] In a non-limiting illustrative embodiment, a wafer transfer method is disclosed for transferring a wafer to an oven chamber. The method includes: positioning a wafer cassette at a loading port of the oven chamber, the wafer cassette containing a wafer boat carrying a semiconductor wafer; pushing the wafer boat out of the wafer cassette and into a wafer cassette fixture positioned at the loading port; supporting the wafer boat during the pushing process as it passes through a gap between the wafer cassette and the wafer cassette fixture using a pontoon bridge; and moving the wafer boat from the wafer cassette fixture into the oven chamber.

[0071] In some embodiments, the support includes guiding the crystal boat through the pontoon bridge using the wall grooves of the pontoon bridge.

[0072] In some embodiments, the method further includes guiding the crystal boat into the pontoon bridge using the outwardly flared end of the wall groove of the pontoon bridge.

[0073] The foregoing outlines features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art will understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or advantages of the embodiments described herein. Those skilled in the art will also recognize that such equivalent structures do not depart from the spirit and scope of the invention, and that various changes, substitutions, and modifications can be made within the invention without departing from its spirit and scope.

Claims

1. A wafer transfer method for transferring a wafer to an oven chamber, the wafer transfer method comprising: A wafer cassette is provided at the loading port of the oven chamber. The wafer cassette contains one or more boats carrying semiconductor wafers, wherein the boats are supported in the wafer cassette by wall grooves. Using a push rod, the one or more wafer boats are transferred away from the wafer cassette and into a wafer cassette fixture provided on the loading port, wherein the transferred one or more wafer boats are supported in the wafer cassette fixture by wall grooves in the wafer cassette fixture; During the transfer, the one or more crystal boats are supported as they pass through the gap between the wafer cassette and the wafer cassette fixture via wall grooves of a bridge inserted between the wafer cassette and the wafer cassette fixture. as well as After the transfer and use of the robot, the one or more wafer boats in the wafer cassette fixture are moved into the oven chamber.

2. The wafer transfer method according to claim 1, further comprising: After the wafer cassette is placed on the loading port of the oven chamber and before the transfer, a motor, pneumatic cylinder, or hydraulic cylinder is operated to lift the pontoon at least partially out of the recess of the loading port.

3. The wafer transfer method according to claim 2, further comprising: Using a second pusher, the one or more wafer boats are transferred a second time away from the wafer cassette fixture and into the wafer cassette, wherein the transferred one or more wafer boats are supported in the wafer cassette by wall grooves in the wafer cassette; During the second transfer, the one or more crystal boats are supported as they pass through the gap between the wafer cassette and the wafer cassette fixture via the wall groove of the bridge inserted between the wafer cassette and the wafer cassette fixture; as well as Remove the wafer cassette from the loading port of the oven chamber.

4. The wafer transfer method according to claim 1, wherein: The wall groove of the wafer cassette is perpendicularly aligned with the corresponding wall groove of the wafer cassette fixture, and The wall groove of the wafer cassette is vertically aligned with the corresponding wall groove of the pontoon bridge.

5. The wafer transfer method of claim 1, wherein, The wall groove of the pontoon bridge has an outwardly flared end.

6. The wafer transfer method of claim 5, wherein, The outwardly extending end has an extension angle of 60 degrees or less.

7. The wafer transfer method of claim 5, wherein, The wall groove of the wafer cassette and the wall groove of the wafer cassette fixture do not have outwardly flared ends or have outwardly flared ends with a flared angle smaller than that of the outwardly flared ends of the wall groove of the pontoon bridge.

8. The wafer transfer method of claim 1, wherein, The gap between the wafer cassette and the wafer cassette fixture is greater than or equal to 0.1 mm and less than or equal to 20 mm.

9. A wafer loading system for loading a wafer boat stored in an associated wafer cassette into an associated oven chamber, the wafer loading system comprising: Wafer box fixture; The loading port has a wafer cassette holder configured to hold the associated wafer cassette and a wafer cassette holder configured to hold the wafer cassette fixture; A bidirectional push rod is configured to push a wafer boat between the associated wafer cassette disposed in the wafer cassette holder and the wafer cassette fixture disposed in the wafer cassette fixture holder; as well as A pontoon bridge is disposed in the gap between the wafer cassette holder and the wafer cassette fixture holder, and is configured to support a pontoon boat that moves between the associated wafer cassette disposed in the wafer cassette holder and the wafer cassette fixture disposed in the wafer cassette fixture holder; The pontoon bridge has wall grooves for supporting a boat that is pushed between the associated wafer cassette disposed in the wafer cassette holder and the wafer cassette fixture disposed in the wafer cassette fixture holder.

10. The wafer loading system according to claim 9, wherein: The associated wafer cassette has wall grooves for supporting a wafer boat stored within it; and The wafer cassette fixture has wall grooves for supporting the wafer boat within the wafer cassette fixture.

11. The wafer load system of claim 10, wherein, The wall grooves of the associated wafer cassette disposed in the wafer cassette holder and the wall grooves of the wafer cassette fixture disposed in the wafer cassette fixture holder are aligned with each other.

12. The wafer loading system of claim 11, further comprising: A motor, pneumatic cylinder, or hydraulic cylinder is operably connected to lift the pontoon from the recess of the loading port to a position where the wall groove of the pontoon aligns with the wall groove of the associated wafer cassette disposed in the wafer cassette holder and the wall groove of the wafer cassette fixture disposed in the wafer cassette fixture holder.

13. The wafer load system of claim 10, wherein, The wall groove of the pontoon bridge has an outwardly flared end.

14. The wafer load system of claim 13, wherein, The outwardly extending end has an extension angle of 60 degrees or less.

15. The wafer load system of claim 13, wherein, The wall groove of the wafer cassette and the wall groove of the wafer cassette fixture do not have outwardly flared ends or have outwardly flared ends with a flared angle smaller than that of the outwardly flared ends of the wall groove of the pontoon bridge.

16. The wafer loading system according to claim 9, further comprising: A multi-axis robot is configured to remove the wafer cassette fixture from the wafer cassette fixture holder at the loading port and transfer the wafer boat in the wafer cassette fixture to the associated oven chamber.

17. The wafer loading system according to claim 9, further comprising: A multi-axis robot configured to transfer the wafer cassette fixture from the wafer cassette fixture holder at the loading port into the associated oven chamber.

18. A wafer transfer method for transferring a wafer to an oven chamber, the wafer transfer method comprising: A wafer cassette is provided at the loading port of the oven chamber, the wafer cassette containing a crystal boat with semiconductor wafers; The crystal boat is pushed out of the wafer cassette and into the wafer cassette fixture located on the loading port; During the pushing process, the crystal boat is supported as it passes through the gap between the wafer cassette and the wafer cassette fixture using a pontoon bridge; as well as The wafer boat in the wafer box fixture is moved into the oven chamber; The support includes: using the wall grooves of the pontoon bridge to guide the crystal boat through the pontoon bridge.

19. The wafer transfer method according to claim 18, wherein, The gap between the wafer cassette and the wafer cassette fixture is greater than 0.1 mm and less than 20 mm.

20. The wafer transfer method according to claim 18, further comprising: The crystal boat is guided into the pontoon bridge by the outwardly flared end of the wall groove.

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