Equipment and method for wafer handling and alignment

Abstract

A method for transporting semiconductor wafers in a semiconductor wafer fabrication plant includes: loading a wafer cassette having at least one semiconductor wafer into a storage buffer of a load port; measuring the position of at least one selected semiconductor wafer within the storage buffer, the selected semiconductor wafer being taken out from the wafer cassette residing within the storage buffer; and determining a difference between the position of the selected semiconductor wafer and a rated position based at least in part on the measurement.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to an apparatus and method for wafer handling and alignment. Background Art

[0002] Embodiments of the present disclosure relate to a semiconductor process technology, particularly a method and apparatus for aligning semiconductor wafers during the process. Summary of the Invention

[0003] According to some embodiments of the present disclosure, there is provided a method for handling semiconductor wafers in a semiconductor wafer manufacturing factory in some embodiments, including: loading a wafer cassette having at least one semiconductor wafer into a storage buffer of a loading port; using an optical sensor disposed in the storage buffer to measure the position of at least one selected semiconductor wafer, the selected semiconductor wafer being taken out from the wafer cassette residing in the storage buffer; and determining a difference between the position of the selected semiconductor wafer and a rated position at least partially based on the measurement.

[0004] According to some embodiments of the present disclosure, there is provided a method for aligning and compensating for a position deviation of a semiconductor wafer from an originally expected rated position. The method includes: accommodating at least one wafer cassette in a storage buffer, at least one wafer cassette carrying at least one semiconductor wafer; detecting the position of at least one selected semiconductor wafer taken out from at least one wafer cassette accommodated in the storage buffer from within the storage buffer; and determining a difference between the selected semiconductor wafer and the rated position at least partially based on the detected position.

[0005] According to some embodiments of the present disclosure, there is provided a loading port for handling and storing semiconductor wafers, including: a storage buffer that accommodates at least one wafer cassette, the at least one wafer cassette carrying at least one semiconductor wafer; and a sensor for detecting the position of at least one selected semiconductor wafer taken out by a robot from at least one wafer cassette. The sensor is accommodated in the storage buffer. Appropriately, at least partially based on the position detected by the sensor, the loading port determines a position difference between a selected semiconductor wafer position and a rated position. Brief Description of the Drawings

[0006] Reading the following detailed description in conjunction with the accompanying drawings will best understand various aspects of the present disclosure. It should be noted that, according to standard practices in the industry, various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of various features may be arbitrarily increased or decreased.

[0007] Figure 1 A front perspective view of a multi-cassette wafer cassette loading port device is schematically shown according to some embodiments disclosed herein.

[0008] Figure 2AA front perspective view of a multi-cassette wafer pod load port device is schematically shown in accordance with some embodiments of the present disclosure.

[0009] Figure 2B is schematically shown Figure 2A a rear perspective view of the multi-cassette wafer pod load port device shown in

[0010] Figure 3 A multi-cassette wafer pod load port device, an equipment front end module, and a manufacturing equipment are schematically shown in accordance with some embodiments of the present disclosure.

[0011] Figure 4 A perspective view of the multi-cassette wafer pod load port device is schematically shown, in which a position sensor and a robot for a wafer transfer system are provided.

[0012] Figure 5 is a flowchart of a wafer position compensation method shown in accordance with some embodiments of the present disclosure. Detailed Description

[0013] The present disclosure provides many different embodiments for implementing different features of the present disclosure. Specific embodiments of components, numerical values, operations, materials, arrangements, or the like and arrangements are set forth below to simplify the present disclosure. Of course, these are only examples and are not intended to be limiting. For example, in the following description, forming a first feature "on" or "above" a second feature may include embodiments in which the first feature and the second feature are formed in direct contact, and may also include embodiments in which additional features may be formed between the first feature and the second feature such that the first feature and the second feature are not in direct contact. Additionally, the present disclosure may reuse reference numerals and / or letters in various embodiments. Such reuse is for the purpose of simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0014] In addition, spatial relative terms, such as "left", "right", "side", "rear", "rear end", "behind", "front", "beneath", "below", "lower", "above", "upper", and the like, may be used herein for ease of description to describe the relationship of one component or feature to another component or feature as shown in the figures. Except for the directions depicted in the figures, the spatial relative terms are intended to encompass different directions of the device during use or operation. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0015] Generally, semiconductor components such as metal-oxide-semiconductor field-effect transistor (MOS-FET) components, integrated circuits (ICs), etc. are fabricated and / or manufactured from semiconductor wafers in a semiconductor fabrication facility (commonly referred to as a wafer fab or wafer foundry). There are typically many process steps applicable to the semiconductor wafer to produce the desired semiconductor components and / or to fabricate multiple semiconductor components on the wafer. For example, the semiconductor process can be a multi-step procedure of lithography, mechanical, and / or chemical processing steps (e.g., such as surface passivation, thermal oxidation, planar diffusion, junction isolation, etc.), during which an electronic circuit and / or semiconductor components are gradually formed on the semiconductor wafer. Thus, a wafer fab cleanroom or other similar space where manufacturing is performed typically contains many individual instruments or equipment for semiconductor component production. For example, but not limited to, steppers and / or scanners for optical lithography, and in addition, equipment for etching, cleaning, doping, testing, inspection, staging, etc. During the manufacturing process, the semiconductor wafer is typically transported or transferred between various equipment and / or otherwise loaded into various equipment using a robotic arm or similar device, such as an equipment front-end module (EFEM).

[0016] Some embodiments disclosed herein relate to a method and apparatus for aligning a semiconductor wafer being transferred from a multi-cassette load port (MCLP) apparatus to a cavity of an apparatus that is to process the semiconductor wafer. One advantage of some embodiments disclosed herein is that it reduces the possible damage to the semiconductor wafer caused by misalignment (e.g., between equipment and / or between equipment and a robot and / or EFEM handling the semiconductor wafer).

[0017] Importantly, in some embodiments, the hardware and / or mechanism for measuring the warpage and / or displacement of the semiconductor wafer is contained and / or housed within the MCLP apparatus itself without any (or any significant) increase in the size of the MCLP instrument. Thus, another advantage of some embodiments disclosed herein is that valuable floor space in a wafer fab cleanroom or other similar space can be saved, at least for some embodiments described herein, without significantly increasing the collective footprint or space in the equipment and / or machines. In other words, by using some embodiments described herein, the additional space typically occupied by conventional mechanical alignment and / or positioning devices can be eliminated or reduced.

[0018] In some embodiments, a fabrication facility (FAB) typically includes one or more floors, rooms, or other similar spaces with multiple process bays, including processing, metrology, and inspection equipment and semiconductor wafer staging equipment, such as wafer stockers, which are interconnected by a computer-controlled automated material handling system (AMHS) for handling the loading of semiconductor wafers in order to transport and transfer wafers within the fabrication facility. During semiconductor manufacturing processes, multiple wafers can be stored and transported together in a wafer carrier (also referred to herein as a cassette) by the AMHS between load ports of different wafer processes or other equipment. As shown, the wafer carrier or cassette can include a standard mechanical interface (SMIF) pod, which can accommodate multiple wafers (e.g., 200 mm diameter wafers), or a front-opening unified pod (FOUP), which can accommodate multiple larger wafers (e.g., 300 mm or 450 mm diameter wafers). In practical applications, each wafer carrier can accommodate a quantity of approximately 25 wafers.

[0019] In some embodiments, an overhead hoist transporter (OHT) system is used to transport a suitable wafer carrier or cassette (e.g., a FOUP or SMIF) from the load port of one piece of equipment to the load port of the next piece of equipment in the process sequence. The OHT system suitably includes one or more carriers (e.g., carriages, trolleys, carts, etc.) that travel on an overhead track or other similar track of the AMHS. A lift on the OHT carrier is operable to selectively raise and lower the wafer carrier, thereby allowing the OHT carrier to deposit and retrieve the wafer carrier from the load port of equipment placed on the floor above and / or below the elevated track or track.

[0020] In some embodiments, the wafer carrier or cassette transported by the OHT system has a door that remains closed during transportation, e.g., for production quality control. To improve production quality and reduce the need for human intervention in the manufacturing process, in some embodiments, the MCLP equipment disclosed herein automatically opens and closes the door of the wafer carrier and can selectively remove the door from the cassette and store the removed door in a door storage unit of a door storage system when the wafer carrier is loaded into the multi-cassette storage buffer of the MCLP equipment.

[0021] In some embodiments, after the MCLP device's platform or load port platform receives a wafer cassette (e.g., from an OHT system or other similar transfer device), the MCLP device has an opening mechanism that automatically opens and / or removes the door of the wafer cassette, and moves the door to the door storage unit of the MCLP device to store the door, while the controller of the MCLP device controls the platform or load port platform to move and / or load the opened wafer carrier into the buffer space of the multi-cassette storage buffer of the MCLP device. Appropriately, the MCLP device may also have a closing mechanism to automatically retrieve the door from the storage unit and place the door on the wafer cassette returning from the storage buffer to the platform or load port platform to close the door. In practical applications, the door retrieved from the door storage unit may not be the original door that was mounted on the wafer cassette before being loaded into the storage buffer, but may be a door of the same model or type as the original door, to be appropriately adapted to the wafer carrier returning from the storage buffer to the workbench or platform. Additionally, the disclosed device can automatically correspond each wafer carrier to its specific door or door storage location, and automatically control the procedures including door opening, storage, and closing. For example, returning a specific door to its specific wafer cassette. In either case, the MCLP device can save manual operation resources and minimize human errors in the production process.

[0022] In some embodiments, the opening mechanism and the closing mechanism are coupled or combined together. The opening / closing mechanism and the door storage system can be installed on the MCLP device and / or integrated with the MCLP device located on the floor of the fab or in the fab. In practical applications, the opening / closing mechanism can include: vacuum holes for applying suction to hold (support) the door, a key for opening / closing the latch of the door, and a moving mechanism for selectively moving the door into or out of the door storage unit of the door storage system. In some embodiments, the door storage system can include one or more storage units, each storage unit for storing the door of the wafer cassette. The moving mechanism can fix the door to the door storage unit, e.g., by alignment pins.

[0023] In some embodiments, the door storage unit is covered by a transparent plate such that an operator can see or view the door through the transparent plate. The MCLP device can include multiple buffer spaces (e.g., in the multi-cassette storage buffer) to buffer multiple wafer carriers before further processing any wafers in the buffered wafer carriers. Appropriately, from the operator's perspective, according to various embodiments, the multiple buffer spaces can be located on the back side, the left side, or the right side of the wafer carrier. Correspondingly, according to various embodiments, the work platform or load port platform can be configured to move the wafer carrier from front to back, from left to right, or from right to left to the buffer space.

[0024] Figure 1Shows the MCLP110 according to some embodiments of the present disclosure. As Figure 1 shown, the MCLP device 110 includes a multi-cassette storage buffer 111, a platform or load port platform 112, a door opening / closing mechanism 116, and a door storage space or door storage system 118.

[0025] As Figure 1 shown, the work platform or load port platform 112 is configured to receive a wafer cassette 120 from a transport device such as a carrier of an OHT system (e.g., as Figure 3 shown). In some embodiments, the carrier 200 of the OHT system is physically coupled to the ceiling of the semiconductor fab and is located at a position higher than the platform or load port platform 112.

[0026] Suitably, the wafer cassette 120 has a door 122 on its back side, i.e., on the side facing the storage buffer 111. As Figure 1 shown, in this example, the door opening / closing mechanism 116 is located on the front side of the housing of the storage buffer 111, i.e., on the side facing the wafer carrier 120. In actual applications, the door opening / closing mechanism 116 can be configured to open the door 122 of the wafer cassette 120 (e.g., by a key 116K of the latch and a vacuum hole 116H for applying a holding suction force, as Figure 1 shown in inset A), and remove the door 122 from the wafer cassette 120 in a direction away from the wafer cassette 120, i.e., in the -X direction as Figure 1 shown, by a relatively short stroke motion. Then, the door opening / closing mechanism 116 can hold the door 122 and move it upward (i.e., in the Z direction) to the door storage system 118.

[0027] As shown, in this embodiment, the door storage system 118 is provided and / or located outside the housing of the multi-cassette storage buffer 111 and is located on the front side of the housing, i.e., on the side facing the wafer carrier 120. In some embodiments, the door storage system 118 can be physically connected to the door opening / closing mechanism 116. In actual applications, the door opening / closing mechanism 116 can be selectively moved relative to the door storage system 118, i.e., in the Z and -Z directions. As Figure 1As shown, the door storage system 118 in this example includes four door storage units. However, it should be understood that the door storage system 118 may include one or more door storage units for selectively storing the doors of the FOUPs. For example, after moving the door 122 upward into one of the door storage units, the door opening / closing mechanism 116 can fix the door 122 to the selected door storage unit by rotating the pins of the door with the key of a suitable latch. Appropriately, when the wafer carrier 120 is loaded and / or otherwise moved into the multi-cassette storage buffer 111, the door 122 remains stored in the door storage unit.

[0028] In some embodiments, the wafer carrier or FOUP 120 is transported to the MCLP device 110 by a transport device (e.g., a carrier of an OHT system), and the elevator on the transport device sets the FOUP 120 from above, i.e., in the -Z direction, on the platform or load port platform 112. As shown, the input / output gateway 119 of the multi-cassette storage buffer 111 faces the back side of the wafer carrier 120. In actual applications, the platform or load port platform 112 can move relative to the housing of the multi-cassette storage buffer 111. In some embodiments, the controller 113 can control the platform or load port platform 112 to selectively move the wafer carrier 120 so that it passes through the gateway 119 and enters the multi-cassette storage buffer 111 (i.e., in the -X direction) to load the FOUP 120 into the storage buffer 111. According to different embodiments, the controller 113 can be disposed below the platform or load port platform 112 (as Figure 1 shown), or can be disposed inside the housing of the storage buffer 111 or at other positions of the MCLP device 110. The controller 113 can be electrically and / or mechanically connected to the platform or load port platform 112 to control the platform or load port platform 112.

[0029] In some embodiments, the equipment front end module (EFEM) 300 (as Figure 3 shown) is suitably coupled to the MCLP 110 for: (a) removing at least one wafer from the FOUP 120 whose door has been opened / removed and stored in the door storage system 118, and then loading the FOUP 120 into the storage buffer 111; (b) transferring the removed wafer onto the chamber 502 of the wafer manufacturing equipment 500 (as Figure 3 shown). In actual applications, the manufacturing equipment 500 to which the wafer is transferred by the EFEM 300 can be a process equipment (e.g., a deposition chamber, an etching chamber, a lithography exposure scanner, a developing equipment, etc.), a vision inspection equipment, and an electrical property detection equipment, etc.

[0030] In some embodiments, after the wafer manufacturing equipment 500 finishes processing the wafer, the wafer can be returned to the wafer cassette 120 in the storage buffer 111, for example, through the EFEM 300. Conversely, the EFEM 300 can also take out the next wafer from the wafer cassette 120 loaded in the storage buffer 111, transfer it to the manufacturing equipment 500 for corresponding processing by the EFEM 300, and return it to its wafer cassette 120 by the EFEM 300. This can be repeated and / or continued for each wafer in turn. Once all (or some other portion) of the wafers from a given wafer cassette 120 in the storage buffer 111 have been properly processed by the manufacturing equipment 500 and returned to the wafer cassette 120, the controller 113 can control the platform or load port platform 112 to unload the wafer carrier 120 from the storage buffer 111, for example, through the gateway 119.

[0031] In some embodiments, after the wafer carrier 120 is unloaded from the storage buffer 111 to the platform or load port platform 112, the door opening / closing mechanism 116 is configured to retrieve the door from the door storage system 118. The retrieved door can be the original door 122 of the wafer carrier 120 before the wafer carrier 120 was loaded into the storage buffer 111, or can be another door of the same model or type as the original door 122 to fit the wafer carrier 120. In practical applications, the door opening / closing mechanism 116 can hold and move the retrieved door downward (i.e., along the -Z direction) from the corresponding door storage unit, and reattach and / or lock the retrieved door to the wafer carrier 120, for example, through the key of the latch and the vacuum hole. Then, the OHT system can retrieve the unloaded and re-closed wafer carrier 120 from the platform or load port platform 112 and transport it to, for example, another load port or equipment to further process one or more semiconductor wafers in the wafer carrier 120.

[0032] In some embodiments, the multi-cassette storage buffer 111 of the MCLP device 110 includes a plurality of buffer spaces that are movably disposed in the storage buffer 111, for example, by a suitable elevator or other similar member. For loading the wafer carrier, the controller 113 can first control the plurality of buffer spaces to selectively move upward or downward (i.e., along the Z or -Z direction) such that one of the unoccupied buffer spaces is aligned with the platform or load port platform 112 and / or the gateway 119. Then, the controller 113 can control the platform or load port platform 112 to move the wafer carrier 120 such that the wafer carrier 120 enters the aligned buffer space through the gateway 119 (i.e., along the -X direction) to load the wafer carrier 120 into the aligned buffer space of the storage buffer 111.

[0033] After one or more opened wafer cassettes are loaded in the storage buffer 111, the EFEM 300 coupled to the MCLP device 110 can selectively retrieve and return wafers from the wafer cassettes in sequence (i.e., from the wafer cassettes whose doors have been opened / removed and are buffered / stored in multiple buffer spaces of the storage buffer 111).

[0034] For the unloading of the wafer carrier of the MCLP device 110, after the manufacturing device 500 has sequentially completed the processing of one or more wafers and has returned the wafers to the opened wafer carrier 120 in the storage buffer 111 (e.g., through the EFEM 300), the controller 113 can control the platform or the load port platform 112 to unload the wafer carrier 120 from the buffer space through the gateway 119. In practical applications, it should be understood that since multiple wafer carriers 120 may be stored and / or buffered in the buffer spaces of the storage buffer 111 at any given time (e.g., waiting for wafer processing), the previously aligned buffer space may be misaligned or displaced with respect to the platform or the load port platform 112 and / or the gateway 119. In this case, the controller 113 can first control the buffer space to selectively move up or down (e.g., along the Z or -Z direction) to realign the previously aligned buffer space with the platform or the load port platform 112 and / or the gateway 119, and then control the platform or the load port platform 112 to unload the wafer carrier 120 from the realigned buffer space.

[0035] According to Figure 1 the illustrated embodiment, when the operator stands in front of the MCLP device 110 and faces the door storage system 118, from the operator's perspective, the storage buffer 111 including multiple buffer spaces is located at the back side of the wafer carrier 120. In this case, from the operator's perspective, the platform or the load port platform 112 is configured to move the wafer carrier 120 from front to back into the buffer space.

[0036] Figure 2A A front perspective view of another MCLP device 110 according to some embodiments of the present disclosure is shown. Figure 2B Shown is Figure 2A the corresponding rear perspective view of the MCLP device 110 shown in Figure 2A and 2B The MCLP 110 shown in Figure 1 has components, assemblies, and / or arrays of components similar to those shown in Figure 2A and 2B and operates in a substantially same manner as described above and elsewhere herein. However, the orientation of the MCLP 110 shown in Figure 1 is different from the orientation shown in Figure 2A and 2BThe MCLP device 110 can be considered a side-loading MCLP device 110 (i.e., from the operator's perspective), while Figure 1 the MCLP device can be considered a front-loading MCLP device 110 (i.e., from the operator's perspective).

[0037] As Figure 2A and 2B shown, the platform or load port platform 112 is configured to receive the wafer carrier 120, whose doors ( Figure 2A and 2B not shown in) are on the back of the wafer carrier 120, i.e., on the side facing the door storage system 118. In this embodiment, the door storage system 118 and the door opening / closing mechanism 116 extend from and / or are coupled to a corner of the housing of the storage buffer 111, i.e., at the left rear corner of the storage (as Figure 2A shown), and extend generally in the X direction relative to the storage buffer 111 from there. In this case, the door opening / closing mechanism 116 is configured to open and / or remove the door of the wafer carrier 120 (e.g., via a key for the latch and a vacuum hole) and move the door towards the back of the wafer carrier 120 (i.e., as Figure 2A and 2B shown, along the -Y direction). The door opening / closing mechanism 116 can then hold the door and move it upward in the Z direction to the door storage system 118, where the door can be selectively stored in the door storage unit while the wafer cassette 120 is loaded into the storage buffer 111.

[0038] In this embodiment, the gateway 119 leading to the storage buffer 111 is provided on the left side of the storage buffer housing (as Figure 2A shown) and faces the right side of the wafer carrier 120. Thus, in this embodiment, the platform or load port platform 112 is configured to selectively move the wafer cassette 120 laterally (i.e., in the -X and / or X directions), e.g., to selectively load the wafer cassette 120 into the buffer space aligned with the storage buffer 111 and / or retrieve it from the buffer space aligned with the storage buffer 111 under the guidance and / or control of the controller 113.

[0039] In Figure 2A and 2B 's embodiment, the EFEM 300 can be coupled to the rear or back of the MCLP device 110 for selectively removing wafers from and / or returning wafers to the wafer carrier 120 (through an opening in the rear or back of the storage buffer 111), whose door has been opened / removed and stored in the door storage system 118, while the wafer carrier 120 is loaded and / or resident in the buffer space 117 of the storage buffer 111.

[0040] According toFigure 2A and Figure 2B In the embodiment shown, when the operator stands in front of the MCLP device 110 and faces the door storage space 118, from the operator's perspective, the storage buffer 111 including a plurality of buffer spaces 117 is located on the right side of the wafer carrier 120 (as Figure 2A shown). In this case, for loading, the platform or load port platform 112 is configured to selectively move the wafer carrier 120 from left to right through the gateway 119 into the aligned buffer space 117 from the operator's perspective. Additionally, it should be understood that in some other embodiments, the storage buffer 111 of the MCLP device 110, including the buffer space, may be located on the left side of the wafer carrier 120, and for loading, from the operator's perspective, the platform or load port platform 112 is configured to move the wafer carrier 120 from right to left to the aligned buffer space. That is, in some embodiments, the MCLP device 110 may be configured and / or set to be substantially as Figure 2A and 2B shown in the mirror image.

[0041] As Figure 3 shown, the carrier 200 of the OHT system selectively transfers and retrieves the wafer cassette 120 from the platform or load port platform 112 of the MCLP device 110. In the illustrated embodiment, the storage buffer 111 of the MCLP device 110 is shown loaded with a plurality of wafer cassettes 120a, 120b, 120c, and 120d. Although four wafer cassettes are shown for the purpose of this example, in actual applications, the storage buffer 111 may accommodate more or fewer than four wafer cassettes.

[0042] In some embodiments, the EFEM 300 is coupled to the MCLP device 110 such that the robot 302 of the EFEM 300 can sequentially and selectively remove and return a selected wafer 400 from a selected wafer cassette within the storage buffer 111. For example, the robot 302 of the EFEM 300 is shown removing the wafer 400 from the wafer cassette 120b. After removing the wafer 400, the EFEM 300 (e.g., via the robot 302) transfers the wafer 400 to the chamber 502 of the manufacturing device 500 and / or places the wafer 400 in the chamber 502 of the manufacturing device 500. After the manufacturing device 500 completes the processing, testing, and / or inspection of the wafer 400, the EFEM 300 retrieves the wafer 400 from the chamber 502 of the manufacturing device 500 and returns the wafer 400 to the wafer cassette within the storage buffer 111 of the MCLP device 110.

[0043] Generally, the EFEM 300 is provided, programmed, and / or otherwise set with position information and / or data indicating the expected rated position of the wafer 400 (i.e., the rated wafer position data as referred to herein). In some embodiments, the EFEM 300 and / or the robot 302 at least partially use the rated wafer position data to accurately retrieve the wafer 400 from the corresponding wafer cassette in the storage buffer 111 and accurately transfer and / or place the wafer 400 into the chamber 502 of the manufacturing equipment 500.

[0044] However, in practical applications, the wafer 400 may not strictly conform to or be located at the rated position indicated by the rated wafer position data. That is, in practical applications, the actual wafer position may vary from the rated wafer position from time to time. As shown in the figure, in practical applications, during various transportation steps or other situations, the wafer 400 may have laterally deviated from the rated position in a certain direction (e.g., in the X-Y direction or the horizontal plane) in practical applications. For example, when there are errors in the size and / or configuration of the wafer cassette carrying the wafer 400 or other similar tolerances that do not precisely limit or fix the wafer 400 in a corresponding position within the wafer cassette, the position of the wafer 400 may differ from the rated position. In addition, for example, warping that occurs naturally or otherwise in the wafer 400 may cause the wafer 400 (or its warped part) to not conform to the rated position in the vertical direction (i.e., the Z-axis direction). That is, if the wafer 400 (or its warped part) is not strictly planar, then in practical applications, the effective height or vertical position (e.g., in the Z direction) on the surface of the wafer 400 may be different from the corresponding rated position. Therefore, only using the rated wafer position data to adjust wafer transfer by the EFEM 300 may result in misalignment, which may cause damage to the wafer 400 transferred by the EFEM 300, for example, when loading and / or placing the wafer 400 into the chamber 502 of the manufacturing equipment 500.

[0045] Accordingly, in some embodiments disclosed herein, the MCLP device 110 is provided, equipped, and / or configured with a compensation system that sends or otherwise provides wafer position offset data to the EFEM 300, and the wafer position offset data (together with the rated wafer position data) can then be used by the EFEM 300 to calculate, correct, and / or compensate for differences in the rated wafer position, for example, when the robot 302 adjusts the wafer transfer system, thereby reducing potential misalignment or dislocation situations.

[0046] As Figure 3As shown, the compensation system includes a wafer position sensor 600 that measures and / or detects the position or orientation of semiconductor wafer 400. In some embodiments, sensor 600 is located within and / or otherwise disposed in a storage buffer 111 included in MCLP device 110 (i.e., within the housing of storage buffer 111, see Figure 4 ), for example, so as not to increase the collective footprint of equipment and / or machines on the fab floor.

[0047] In actual applications, the wafer position sensor 600 is an optical sensor that is disposed and / or oriented towards the top of the storage buffer 111 (i.e., in the Z direction) and aimed, pointed, or otherwise vertically downward, e.g., perpendicular to the horizontal plane of the wafer 400 and / or the transfer path (i.e., perpendicular to the X-Y plane in the illustrated embodiment), to capture an image of the wafer 400 within its field of view (FoV) 602. In some embodiments, sensor 600 can be oriented plus or minus 30 degrees off normal to allow for flexibility in the design of MCLP device 110 and / or to provide flexibility in the placement of sensor 600 within storage buffer 111. Sensor 600 and its FoV 602 are positioned, aimed, and / or oriented and are between the open doors of wafer cassettes 120a, 120b, 120c, and 120d stored in storage buffer 111 on one side and EFEM 300 and / or its robot 302.

[0048] In some embodiments, the sensor 600 obtains three-dimensional (3D) position information and / or data based on measuring or detecting the position of the wafer 400 within the FoV 602. In some embodiments, the position sensor 600 is an optical sensor (e.g., a linear array using a camera, raster laser beam, light emitting diode (LED), or laser diode, and various combinations thereof, etc.). As shown, the optical wafer position sensor can be a machine vision (MV) sensor and can include any one or more of an area camera, a pair of stereo vision cameras, a profile scanner, and / or a laser displacement sensor. For example, in some embodiments, the area camera can obtain or capture a two-dimensional (2D) image of the entire wafer 400 within the FoV 602. In certain alternative embodiments, when the wafer 400 passes through the FoV 602, the profile scanner can obtain or capture a 2D image of the wafer 400 row by row. Appropriately, in some embodiments, the laser displacement sensor measures or otherwise detects the depth or displacement of the wafer 400 (e.g., along the Z direction), such as using the measurement of the pulsed laser time-of-flight distance or the interference optical phase displacement of the reflected light, so that a corresponding surface profile or depth map can be at least partially created or derived therefrom. In some alternative embodiments, the sensor 600 employs a pair of stereo vision cameras from which 3D image data can be obtained. In some embodiments, the sensor 600 can be composed of various combinations of any one or more of the foregoing configurations to obtain 3D measurements and / or detections of the wafer position or orientation.

[0049] In some embodiments, the degree and / or direction of wafer warping (i.e., warping of the wafer 400 in the Z and / or -Z directions) and / or the amount and / or direction of wafer movement (i.e., movement of the wafer 400 in a direction within the X-Y plane) are calculated at least partially based on the information and / or data captured and / or obtained by the position sensor 600. As shown, the warpage and the distance and difference by which the wafer 400 deviates from the rated position can be calculated at least partially based on the 3D position data and / or the information obtained by the position sensor 600. In some embodiments, wafer warping greater than or equal to about 1000 um can be detected and / or calculated. In some embodiments, wafer offset greater than or equal to about 0.5 mm can be detected and / or calculated.

[0050] In some embodiments, the calculated and / or otherwise obtained warpage and / or offset of the wafer 400 (e.g., which describes the potential change or difference in the position and / or location of the wafer relative to the expected rated wafer position and / or location) can be converted and / or otherwise used to derive the above-described wafer position offset data, which is sent and / or provided to the EFEM 300. In some embodiments, this conversion and / or derivation provides the wafer position offset data in the coordinate system recognized and / or used by the EFEM 300. In some suitable embodiments, the EFEM 300 at least partially employs the received wafer position offset data to further adjust or control the operation of the robot 302 for handling the wafer 400, thereby alleviating potential misalignment that may cause damage to the wafer 400. For example, when the robot 302 loads and / or places the wafer 400 into the chamber 502 of the manufacturing device 500. That is, the EFEM 300 uses the wafer position offset data to account for, correct, and / or compensate for the difference between the wafer 400 and the rated wafer position, e.g., when adjusting and / or controlling the wafer transfer system by the robot 302.

[0051] Reference Figure 4 to the disclosed method, in which the optical wafer position sensor 600 is disposed inside the MLCP device 110, has the advantage of reducing the footprint of the components. In this regard, although Figure 4 the optical wafer position sensor 600 is shown for illustrative purposes, in actual assembly, the sensor 600 may be disposed inside the MLCP device 110 and thus be blocked (as Figure 3 shown). As Figure 4 shown in the perspective view of, the FoV 602 for performing the optical measurement of the wafer position can also be disposed inside the MLCP device 110. With this arrangement, the wafer position (e.g., lateral shift and / or warpage) is measured before the wafer is handled by the robot 302 and placed into the manufacturing device 500 (see Figure 3 ). By transmitting the wafer position information to the robot 302 or other wafer transfer system devices (generally, using the equipment front-end module or EFEM 300) before complex wafer transfer, the robot 302 can be programmed to accommodate wafer shift and / or warpage, thereby ensuring the precise position of the wafer in the manufacturing device 500, improving the accuracy of the wafer transfer system, and reducing the likelihood of wafer damage due to misoperation of the robot 302.

[0052] Now refer Figure 5 to, the illustrated flowchart depicts a method and / or process 700, e.g., performed by the above-described compensation system according to some embodiments disclosed herein.

[0053] As shown, in step 702, sensor 600 measures or otherwise detects the 3D position of wafer 400 within FoV 602.

[0054] As shown, in step 704, the warpage of wafer 400 (e.g., describing or reflecting the degree of warpage of wafer 400 (e.g., in the Z and / or -Z directions) and / or offset (e.g., in the X-Y plane) to position or orient the rated wafer is calculated or otherwise determined at least in part using and / or based on the measurements obtained in step 702.

[0055] As shown, in step 706, the wafer position offset data is calculated and / or otherwise determined at least in part using the warpage and / or shift obtained in step 704. Appropriately, the wafer position offset data describes or reflects the warpage and / or offset of wafer 400 relative to the rated wafer position in the coordinate system recognized and / or adopted by EFEM 300, e.g., the rated wafer position is otherwise determined by EFEM 300.

[0056] As shown, in step 708, the wafer position offset data is sent or provided to EFEM 300.

[0057] As shown, in step 710, EFEM 300 uses the received wafer position offset data at least in part to periodically and / or control the handling of wafer 400 by robot 302, e.g., for loading and / or placing wafer 400 into the chamber of the device.

[0058] Measuring the lateral displacement and warpage of the wafer advantageously provides wafer position offset data in both the lateral (e.g., X- and / or Y-) and vertical (e.g., Z-) directions, thus providing the most information for adjusting the handling of the wafer by EFEM 300. However, in some cases, only the lateral displacement can be measured, or only the warpage can be measured. As an example of a case where the warpage measurement may be omitted, early in the manufacturing process, there may be few or no deposited layers on the wafer. Since warpage is typically caused by the deposition of different materials on the wafer (e.g., due to the difference in thermal expansion between the deposited material and silicon or other wafer materials; or e.g., due to lattice mismatch in the case of epitaxial deposition), it may not be necessary to measure the wafer warpage when transferring the wafer early in the manufacturing process. Similarly, if the wafer diameter is very small, it can be assumed that the warpage is negligible. An example of a case where the lateral offset measurement may be omitted is if robot 302 and manufacturing equipment 500 are designed to accept significant wafer offsets, then only some offset errors are unlikely to cause problems.

[0059] In some embodiments, controller 113 may communicate effectively with sensor 600 and EFEM 300, and may be programmed and / or otherwise provided to implement the functions performed by the compensation system and / or to execute process 700. In some alternative embodiments, a separate controller may be used for the compensation system. In some embodiments, the compensation system controller may be located remotely or elsewhere, such as outside of MCLP device 110.

[0060] In some embodiments, controller 113 and / or the compensation system controller may be implemented by hardware, software, firmware, or combinations thereof. In particular, one or more controllers may be embodied by a processor, circuitry, a computer, and / or other electronic data processing means, which are configured and / or otherwise provided to perform the tasks, steps, processes, methods, and / or functions described herein. For example, a processor, computer, server, or other electronic data processing means embodying the controller may be provided with a suitable list of program code (e.g., source code, interpreted program code, object code, directly executable program code, etc.) or other similar instructions or software or firmware such that when run and / or executed by the computer or other electronic data processing means, one or more of the tasks, steps, processes, methods, and / or functions described herein are completed or otherwise accomplished. Suitably, the list of program code or other similar instructions or software or firmware is implemented as and / or recorded, stored, contained, or included in and / or on a non-transitory computer and / or machine-readable storage medium or media so as to be provided to and / or executable by the computer or other electronic data processing device. For example, suitable storage media and / or media may include, but are not limited to: floppy disks, hard disks, magnetic tapes, or any other magnetic storage media or media, CD-ROMs, DVDs, optical disks, or any other optical media or media, RAMs, ROMs, PROMs, EPROMs, flash-EPROMs, or other memories or chips or chip cartridges, or any other tangible media or media from which a computer, machine, or electronic data processing device can read and use. Substantially, as used herein, non-transitory computer-readable and / or machine-readable media and / or media include all computer-readable and / or machine-readable media other than transitory and propagating signals.

[0061] In general, any one or more of the specific tasks, steps, processes, methods, functions, components, and / or assemblies described herein can be implemented on one or more general-purpose computers, special-purpose computers, and / or embodiments. Programmed microprocessors or microcontrollers and interface device integrated circuit components, ASICs, or other integrated circuits, digital signal processors, hard-wired electronic or logic circuits, such as discrete component circuits, programmable logic devices, such as PLDs, PLAs, FPGAs, graphics adapter CPUs (GPUs), or PALs, etc. In general, any device capable of implementing a finite state machine can be used, and the finite state machine can in turn implement the corresponding tasks, steps, processes, methods, and / or functions described herein.

[0062] In the following, some further illustrative embodiments are described.

[0063] In some embodiments, a method of handling semiconductor wafers in a semiconductor wafer fabrication plant includes: loading a wafer cassette having at least one semiconductor wafer into a storage buffer of a load port; using an optical sensor disposed within the storage buffer to measure the position of at least one selected semiconductor wafer, the selected semiconductor wafer being taken out from the wafer cassette residing within the storage buffer; and determining a difference between the position of the selected semiconductor wafer and a rated position based at least in part on the measurement.

[0064] In some additional embodiments, the method further includes transmitting the determined difference to an equipment front-end module connected to the load port so that the equipment front-end module controls its handling of the selected semiconductor wafer at least in part based on the determined difference.

[0065] In further embodiments, the difference includes a difference between the position of the selected semiconductor wafer and the rated position in at least three dimensions.

[0066] In some embodiments, the determination includes at least one of the following: determining the warpage of the selected semiconductor wafer in a first direction; and determining the lateral movement of the selected semiconductor wafer in a second direction within the normal plane of the first direction.

[0067] In still further embodiments, the method further includes converting the determined difference into wafer position offset data, which is transmitted to the equipment front-end module, such that the equipment front-end module controls its handling of the selected semiconductor wafer at least in part based on the wafer position offset data.

[0068] In further embodiments, the position offset data shows the determined difference in a coordinate system recognized by the equipment front-end module.

[0069] In some embodiments, the measurement is performed by a machine vision sensor disposed within the storage buffer of the load port.

[0070] In a further embodiment, the machine vision sensor includes at least one of an area camera, a pair of stereo vision cameras, a profile scanner, and a laser displacement sensor.

[0071] In some embodiments, the aiming direction of the machine vision sensor is perpendicular to the travel path followed when a selected semiconductor wafer is removed from the wafer cassette.

[0072] In some further embodiments, the aiming range of the machine vision sensor is within plus or minus 30 degrees of the normal direction of the action path followed when a selected semiconductor wafer is removed from the wafer cassette.

[0073] In a still further embodiment, the machine vision sensor has a field of view between the wafer cassette loaded in the storage buffer machine loaded onto the load port and the robot of the equipment front end module coupled to the load port, for transporting a selected semiconductor wafer into the equipment chamber to process the selected semiconductor wafer.

[0074] In another embodiment, a method for calibrating and compensating for the positional deviation of a semiconductor wafer from its originally expected rated position is provided. The method includes: accommodating at least one wafer cassette in the storage buffer machine, where at least one semiconductor wafer is carried in at least one wafer cassette; detecting, from within the storage buffer machine, the position of at least one selected semiconductor wafer removed from at least one wafer cassette accommodated in the storage buffer machine; and determining, at least in part based on the detected position, the difference between the selected semiconductor wafer and the rated position.

[0075] In some further embodiments, the determining includes: determining a first difference of the selected semiconductor wafer in a first direction; and determining a second difference of the selected semiconductor wafer in a second direction within the normal plane of the first direction.

[0076] In some additional embodiments, the method further includes determining wafer position offset data at least in part based on the first difference and the second difference.

[0077] In some embodiments, the method further includes transmitting the wafer position offset data to the equipment front end module so that, after receiving the wafer position offset data, the equipment front end module controls the handling of the selected semiconductor wafer by the robot at least in part based on the wafer position offset data it receives.

[0078] In some embodiments, the detection is performed by a sensor, and the optical sensor has a field of view between at least one wafer cassette disposed in the storage buffer machine and the robot.

[0079] In a further embodiment, the sensor is disposed within the storage buffer machine.

[0080] In a further embodiment, a load port for handling and storing semiconductor wafers includes: a storage buffer that houses at least one wafer cassette, and at least one semiconductor wafer is carried in the at least one wafer cassette; and a sensor for detecting the position of at least one selected semiconductor wafer taken out by a robot from the at least one wafer cassette. The sensor is housed in the storage buffer. Appropriately, based at least in part on the position detected by the sensor, the load port determines the position difference between a selected semiconductor wafer position and a rated position.

[0081] In another embodiment, the position detected by the sensor is three-dimensional position information.

[0082] The features of several embodiments are outlined above so that those skilled in the art can better understand various aspects of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purpose and / or realize the same advantages as the embodiments described herein. Those skilled in the art should also recognize that these equivalent structures do not depart from the spirit and scope of the present disclosure, and they can make various changes, substitutions, and alterations without departing from the spirit and scope of the present disclosure.

[0083] [Description of Symbols]

[0084] 110: MCLP device

[0085] 111: Multi-cassette storage buffer

[0086] 112: Platform

[0087] 113: Controller

[0088] 116: Door opening / closing mechanism

[0089] 116H: Vacuum hole

[0090] 116K: Key of latch

[0091] 117: Buffer space

[0092] 118: System

[0093] 119: Gateway

[0094] 120, 120a, 120b, 120c, 120d: Wafer cassette

[0095] 122: Door

[0096] 200: Carrier

[0097] 300: Equipment Front End Module

[0098] 302: Robot

[0099] 400: Wafer

[0100] 500: Equipment

[0101] 502: Chamber

[0102] 600: Sensor

[0103] 602: Field of view

[0104] 700: Process

[0105] 702, 704, 706, 708, 710: Steps

Claims

1. A method for handling semiconductor wafers, the method comprising: Loading a cassette having at least one of the semiconductor wafers into a storage buffer of a load port; Using an optical sensor disposed within the storage buffer to measure the position of at least one selected semiconductor wafer removed from the cassette residing within the storage buffer; And Based at least in part on the measurement, determining a difference between the position of the selected semiconductor wafer and a rated position, Wherein the determining includes: Determining the warpage of the selected semiconductor wafer in a first direction; And Determining the lateral movement of the selected semiconductor wafer in a second direction within the normal plane of the first direction.

2. The method according to claim 1, further comprising: Transmitting the determined difference to an equipment front-end module connected to the load port so that the equipment front-end module controls its handling of the selected semiconductor wafer at least in part based on the determined difference.

3. The method according to claim 1, wherein the difference includes the difference between the position of the selected semiconductor wafer and the rated position in at least three dimensions.

4. The method according to claim 1, further comprising: Converting the determined difference into wafer position offset data, the data being transmitted to the equipment front-end module so that the equipment front-end module controls its handling of the selected semiconductor wafer at least in part based on the wafer position offset data.

5. The method according to claim 4, wherein the position offset data shows the determined difference in a coordinate system recognized by the equipment front-end module.

6. The method according to claim 1, wherein the measurement is performed by a machine vision sensor disposed within the storage buffer of the load port.

7. The method according to claim 6, wherein the machine vision sensor includes at least one of an area camera, a pair of stereo vision cameras, a contour scanner, and a laser displacement sensor.

8. The method according to claim 6, wherein the aiming direction of the machine vision sensor is perpendicular to the travel path followed when the selected semiconductor wafer is removed from the cassette.

9. The method according to claim 6, wherein the aiming range of the machine vision sensor is within plus or minus 30 degrees of the normal direction of the action path followed when the selected semiconductor wafer is removed from the cassette.

10. The method according to claim 6, wherein the machine vision sensor has a field of view between the cassette loaded into the storage buffer of the load port and a robot of the equipment front-end module coupled to the load port for transporting the selected semiconductor wafer into an equipment cavity for processing the selected semiconductor wafer.

11. A method for calibrating the position deviation of a semiconductor wafer, the method comprising: Receiving at least one cassette in a storage buffer, the at least one cassette carrying at least one semiconductor wafer; Detect the position of taking out at least one selected semiconductor wafer from at least one wafer cassette accommodated in the storage buffer; and Based at least in part on the detected position, determine the difference between the selected semiconductor wafer and the rated position, wherein the determination includes: Determine a first difference of the selected semiconductor wafer in a first direction; and Determine a second difference of the selected semiconductor wafer in a second direction within the normal plane of the first direction.

12. The method according to claim 11, further comprising: Determine wafer position offset data based at least in part on the first difference and the second difference.

13. The method according to claim 12, further comprising: Transmit the wafer position offset data to the equipment front-end module, so that after receiving the wafer position offset data, the equipment front-end module controls the handling of the selected semiconductor wafer by the robot based at least in part on the received wafer position offset data.

14. The method according to claim 13, wherein the detection is performed by an optical sensor, and the optical sensor has a field of view between at least one of the wafer cassettes disposed in the storage buffer and the robot.

15. The method according to claim 14, wherein the optical sensor is disposed within the storage buffer.

16. A load port device for transporting and storing semiconductor wafers, the load port comprising: A storage buffer that accommodates at least one wafer cassette, and at least one semiconductor wafer is carried in the at least one wafer cassette; and A sensor for detecting the position of at least one selected semiconductor wafer taken out by the robot from at least one wafer cassette, and the sensor is accommodated in the storage buffer, wherein, based at least in part on the position detected by the sensor, the load port determines the position difference between a selected semiconductor wafer position and the rated position, and the determination includes: Determine the warpage degree of the selected semiconductor wafer in a first direction; and Determine the lateral movement of the selected semiconductor wafer in a second direction within the normal plane of the first direction.

17. The device according to claim 16, wherein the position detected by the sensor is three-dimensional position information.

18. The device according to claim 16, wherein: The at least one wafer cassette includes a plurality of wafer cassettes; The storage buffer includes a plurality of buffer spaces, and each of the buffer spaces can accommodate one of the plurality of wafer cassettes; and The storage buffer is configured to selectively move the plurality of buffer spaces so as to align a selected buffer space among the plurality of buffer spaces with the gateway, and selectively load the wafer cassette into the storage buffer through the gateway.

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