Wafer handling method and load port

Abstract

To provide a wafer handing method and device for preventing wafer from being damaged by positional deviation while being moved to a device due to a positional variation of wafers in a wafer housing container.SOLUTION: A method for handling semiconductor wafers in a space of a semiconductor wafer processing facility (a multi-cassette load port (MCLP) device 110) includes: loading a cassette 120 containing at least one semiconductor wafer into a storage buffer 111 of a load port; measuring a position of at least one selected semiconductor wafer to be extracted from the cassette existing in the storage buffer from within the storage buffer; and determining a variation in the position of the selected semiconductor wafer from a reference position on the basis of at least partial measurement.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure generally relates to wafer handling methods and load ports as wafer handling devices. [Background technology]

[0002] The following relates to semiconductor manufacturing technology, and more particularly to methods and apparatus for aligning semiconductor wafers during the manufacturing process. Summary of the Invention [Problem to be solved by the invention]

[0003] The present disclosure is intended to solve the problem of potential damage to semiconductor wafers due to misalignment between tools handling the semiconductor wafers and / or between the tools and robots and / or Equipment Front-End Modules (EFEMs). [Means for solving the problem]

[0004] In order to achieve the above object, the present disclosure provides a wafer handling method for handling semiconductor wafers in a space of a semiconductor wafer processing facility, the wafer handling method including: loading a cassette containing at least one semiconductor wafer into a storage buffer of a load port, measuring from within the storage buffer a position of at least one selected semiconductor wafer to be removed from a cassette residing in the storage buffer using an optical sensor provided in the storage buffer, and determining a difference in position of the at least one selected semiconductor wafer from a reference position based at least in part on the measurement.

[0005] To achieve the above objectives, the present disclosure also provides a method of wafer handling as a compensation method for semiconductor wafers whose positions differ from an expected reference position, the method of wafer handling including: holding at least one cassette containing at least one semiconductor wafer in a storage buffer, detecting from within the storage buffer a position of at least one selected semiconductor wafer to be removed from the at least one cassette held in the storage buffer, and determining a difference in the position of the at least one selected semiconductor wafer from a reference position based at least in part on the position detected by a sensor.

[0006] To achieve the above objectives, the present disclosure also provides a load port for staging semiconductor wafers, the load port including a storage buffer for holding at least one cassette containing at least one semiconductor wafer, and a sensor housed in the storage buffer for detecting a position of at least one selected semiconductor wafer retrieved by a robot from the at least one cassette, and a difference in position of the at least one selected semiconductor wafer from a reference position is preferably determined by the load port based at least in part on the position detected by the sensor. Effect of the Invention

[0007] Based on the above, hardware and / or mechanisms for measuring the bow and / or misalignment of semiconductor wafers may be included and / or housed in the tool itself, thus allowing alignment of semiconductor wafers transferred from the tool to a chamber, reducing the possibility of damage to the semiconductor wafers, and also conserving floor space or similar space in a FAB clean room. [Brief description of the drawings]

[0008] Aspects of the present disclosure are best understood by reading the following detailed description in conjunction with the accompanying drawings, in which: It should be noted that, in accordance with standard practice in the industry, various features have not been drawn to scale, and in fact, the sizes of various features depicted in the accompanying drawings may be arbitrarily increased or reduced for illustrative clarity. [Figure 1] FIG. 1 is a schematic front perspective view of a multi-cassette load port apparatus according to some embodiments of the present disclosure. [Figure 2A] FIG. 2A is a schematic front perspective view of a multi-cassette load port apparatus according to some other embodiments of the present disclosure. [Figure 2B] FIG. 2B is a schematic rear perspective view of the multi-cassette load port apparatus shown in FIG. 2A. [Diagram 3] FIG. 3 is a schematic perspective view of a multi-cassette load port apparatus, an EFEM, and a tool according to some embodiments of the present disclosure. [Figure 4] FIG. 4 is a schematic perspective view of a multi-cassette load port device provided with a position sensor and a robot that handles wafers. [Diagram 5] FIG. 5 is a flow diagram illustrating a method for wafer position compensation according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following embodiments provide many different embodiments or examples for implementing different features of the provided subject matter. To simplify the present disclosure, specific examples of components and arrangements are described below. Of course, these are illustrative and not intended to be limiting. For example, a configuration of a first feature above or on a second feature in the following description may include an embodiment in which the first and second features are formed in direct contact, and may also be an embodiment in which an additional feature is formed between the first and second features such that the first and second features are not in direct contact. In addition, the present disclosure may repeat symbols in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself dictate a relationship between the various embodiments and / or configurations referred to.

[0010] Additionally, spatially relative terms such as "left," "right," "side," "rear," "behind," "rear," "front," "below," "lower," "upper," "above," and the like may be used to facilitate the description to explain the relationship of one element or feature depicted in the figures to another element or feature. The spatially relative terms are intended to encompass different orientations of the device during use or operation in addition to the orientation depicted. The device may be otherwise oriented (rotated 90 degrees or in other orientations) and the spatially relative descriptors used herein may be interpreted accordingly.

[0011] Typically, semiconductor devices such as metal oxide semiconductor field effect transistor (MOS-FET) devices, integrated circuits (ICs), etc. are fabricated and / or assembled from semiconductor wafers in a semiconductor manufacturing facility commonly referred to as a FAB or foundry. There are typically many processing steps applied to the semiconductor wafer to fabricate the desired semiconductor device and / or semiconductor devices on the wafer. For example, semiconductor fabrication can be a multi-step sequence of photolithography, mechanical and / or chemical processing steps (e.g., surface passivation, thermal oxidation, planar diffusion, junction isolation, etc.) by which electronic circuits and / or semiconductor devices are gradually created on the semiconductor wafer. Thus, the FAB clean room or other similar space in which fabrication takes place typically includes many individual machines or tools for semiconductor device fabrication, such as, but not limited to, steppers and / or scanners for photolithography, in addition to tools for etching, cleaning, doping, testing, inspection, staging, etc. During the fabrication process, the semiconductor wafer is typically transferred or transported from tool to tool or loaded into various tools using, for example, a robotic arm, such as an EFEM.

[0012] Some embodiments disclosed herein relate to an apparatus and method for aligning semiconductor wafers transferred from a multi-cassette load port (MCLP) apparatus to a chamber of a tool where the semiconductor wafers are processed. One advantage of some embodiments disclosed herein is that potential damage to the semiconductor wafers due to misalignment (e.g., between tools and / or between the tool and a robot and / or EFEM handling the semiconductor wafers) is reduced.

[0013] Significantly, in some embodiments, the hardware and / or mechanisms for measuring the bow and / or misalignment of the semiconductor wafer are contained and / or housed within the MCLP apparatus itself, without any (or apparent) increase in the size of the MCLP apparatus. Thus, another advantage of some embodiments disclosed herein is that valuable floor space in a FAB clean room or other similar space is conserved, and at least in some embodiments described herein, the collective footprint of the tools and / or machines in the FAB space is not significantly increased. In other words, the extra footprint typically occupied by conventional mechanical alignment and / or positioning apparatus can be eliminated or reduced by some embodiments described herein.

[0014] In some embodiments, a FAB typically includes one or more floors, rooms, or other similar spaces with multiple processing bays, including processing, metrology, and inspection tools, and semiconductor wafer staging equipment, such as stockers, interconnected by a computer-controlled automated material handling system (AMHS) to handle staging of semiconductor wafers for processing and flow in and out of the FAB. Multiple wafers may be stored together in wafer carriers (also referred to herein as cassettes) and transported by an AHMS between different wafer processing load ports or other tools during the semiconductor manufacturing process. For example, a wafer carrier or cassette may include a Standard Mechanical Interface (SMIF) pod capable of holding multiple wafers (e.g., 200 mm diameter wafers), or a Front Opening Unified Pod (FOUP) capable of holding multiple relatively large wafers, e.g., 300 mm or 450 mm diameter wafers. In practice, each wafer carrier may hold an array of approximately 25 wafers.

[0015] In some embodiments, an overhead hoist transport (OHT) system is used to transport suitable wafer carriers or cassettes, such as FOUPs or SMIFs, from the load port of one tool to the load port of the next tool in processing sequence. The OHT system preferably includes one or more dollies (e.g., trolleys, carts, carriages, etc.) that travel on overhead rails or other similar tracks of the AMHS. A hoist mounted on the OHT dolly can selectively raise and lower the wafer carriers, allowing the OHT dolly to place and remove the wafer carriers in and from the load ports of tools located along and / or on the floor below the overhead rails or tracks.

[0016] In some embodiments, the wafer carriers or cassettes transported by the OHT system have doors that remain closed during the transfer process, e.g., for manufacturing quality control. To improve manufacturing quality and reduce the need for human intervention in the manufacturing process, in some embodiments, the MCLP apparatus disclosed herein may automatically open and close the doors of the wafer carriers, selectively remove the doors from the cassettes while the wafer carriers are loaded into the multi-cassette storage buffer of the MCLP apparatus, and store the removed doors in a door storage portion of a door storage system.

[0017] In some embodiments, after the table or load port stage of the MCLP apparatus receives a cassette (e.g., from an OHT system or other similar transfer tool), the MCLP apparatus has an opening mechanism that automatically opens and / or removes the door of the cassette and moves the door to a door storage section of the MCLP apparatus for storing the door while a controller of the MCLP apparatus controls the table or load port stage to move and / or load the opened wafer carrier into the buffer space of the multi-cassette storage buffer of the MCLP apparatus. The MCLP apparatus also preferably has a closing mechanism for automatically removing the door from the storage section and closing the door on the cassette returned from the storage buffer to the table or load port stage. In fact, the door removed from the door storage section may not be the original door that was on the cassette before it was loaded into the storage buffer, but may be the same model or type of door as the original door that fits well with the wafer carrier returned from the storage buffer to the table or storage. Alternatively, the disclosed apparatus can automatically map each wafer carrier to its specific door or door storage location and automatically control the opening, storage, and closing of the doors, for example to return a given door to its specific cassette. In either case, the MCLP apparatus can conserve human operating resources and reduce human error on the manufacturing floor.

[0018] In some embodiments, the opening mechanism and the closing mechanism are coupled or combined together. The opening / closing mechanism and the door storage system may be attached and / or coupled to an MCLP device located on the floor or in the space of the FAB. In practice, the opening / closing mechanism may include a vacuum hole to apply suction to hold the door, a latch key to open and close the door, and a movement mechanism to selectively move the door into and out of a door storage section of the door storage system. In some embodiments, the door storage system may include one or more storage sections, each of which stores a cassette door. The movement mechanism may secure the door to the door storage section, for example, by an alignment pin.

[0019] In some embodiments, the door storage is covered by a transparent plate through which the operator can see the door. The MCLP device may include multiple buffer spaces (e.g., in a multi-cassette storage buffer) for buffering multiple wafer carriers before the wafers in the buffered wafer carriers are further processed. From the operator's perspective, the multiple buffer spaces are preferably located at the rear of the wafer carrier, the left side of the wafer carrier, or the right side of the wafer carrier, depending on various embodiments. Correspondingly, the table or load port stage may be configured to move the wafer carriers into the buffer spaces from front to back, left to right, or right to left, depending on various embodiments.

[0020] 1 illustrates an MCLP apparatus 110 according to some embodiments of the present disclosure. As shown in FIG. 1, the MCLP apparatus 110 includes a multi-cassette storage buffer 111, a table or load port stage 112, a door opening and closing mechanism 116, and a door storage space or system 118.

[0021] 1, the table or stage 112 is configured to receive the cassette 120 from a transport tool, such as a dolly of an OHT system (e.g., as shown in FIG. 3). In some embodiments, the dolly 200 of the OHT system is physically coupled to the ceiling of the FAB and is at a higher position than the table or stage 112.

[0022] The cassette 120 preferably has a door 122 at its rear, i.e., on the side facing the storage buffer 111. As shown in Fig. 1, the door opening / closing mechanism 116 in this embodiment is located at the front side of the housing of the storage buffer 111, i.e., on the side facing the wafer carrier 120. In practice, the door opening / closing mechanism 116 may be configured to open the door 122 of the cassette 120 (e.g., by means of a latch key 116K and a vacuum hole 116H for applying holding suction, as shown in inset A of Fig. 1) and remove the door 122 from the cassette 120 (by a relatively short stroke movement) in a direction away from the cassette 120, i.e., in the -X direction as shown in Fig. 1. The door opening / closing mechanism 116 then holds the door 122 and moves it up (i.e., along the Z direction) into the door storage system 118.

[0023] As shown, the door storage system 118 of this embodiment is disposed 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., the side facing the wafer carrier 120. In some embodiments, the door storage system 118 may be physically connected to the door opening mechanism 116. In fact, the door opening mechanism 116 is selectively movable relative to the door storage system 118, i.e., along the Z and -Z directions. As shown in FIG. 1, the door storage system 118 of this embodiment includes four door storage sections. However, it is understood that the door storage system 118 may include one or more door storage sections for selectively storing the cassette doors. For example, after moving the door 122 up into one of the door storage sections, the door opening mechanism 116 may rotate a door pin with an appropriate latch key to secure the door 122 in the selected door storage section. Preferably, the door 122 remains stored in the door storage section while the wafer carrier 120 is being loaded or moved into the multi-cassette storage buffer 111 .

[0024] In some embodiments, the wafer carrier or cassette 120 is transported to the MCLP apparatus 110 by a transport tool (e.g., a dolly of an OHT system), and a hoist mounted on the transport tool places the cassette 120 on the table or stage 112 from top to bottom, i.e., along the -Z direction. As shown, the multi-cassette storage buffer 111 has an input / output gateway 119 facing the rear side of the wafer carrier 120. In practice, the table or stage 112 is movable relative to the housing of the multi-cassette storage buffer 111. In some embodiments, the controller 113 may control the table or stage 112 to selectively move the wafer carrier 120 into the multi-cassette storage buffer 111 (i.e., along the -X direction) via the gateway 119 to load the cassette 120 into the storage buffer 111. According to various embodiments, the controller 113 may be located below the table or stage 112 (as shown in FIG. 1 ), within the housing of the storage buffer 111, or elsewhere in the MCLP apparatus 110. The controller 113 may be electrically and / or mechanically connected to the table / stage 112 for controlling the table / stage 112 .

[0025] In some embodiments, the EFEM 300 (as shown in FIG. 3 ) is preferably coupled to the MCLP apparatus 110 for (a) retrieving at least one wafer from a cassette 120 whose door has been opened / removed and stored in the door storage system 118 and subsequently loaded into the storage buffer 111, and (b) transferring the retrieved wafer to a chamber 502 of a wafer processing tool 500 (as shown in FIG. 3 ). In practice, the processing tool 500 to which the wafer is transferred by the EFEM 300 may be a manufacturing tool (e.g., a deposition chamber, an etch chamber, a lithography exposure scanner, a development tool, etc.), a visual inspection tool, an electrical property test tool, etc.

[0026] In some embodiments, after tool 500 has finished a wafer, the wafer may be returned, for example by EFEM 300, to its cassette 120 in storage buffer 111. The next wafer may then be similarly removed by EFEM 300 from the cassette 120 loaded in storage buffer 111, transported by EFEM 300 to processing tool 500, processed as appropriate, and returned by EFEM 300 to its cassette 120. This may be repeated and / or continued in this manner for each wafer in sequence. Once all (or a portion) of the wafers from a given cassette 120 in storage buffer 111 have been properly processed by processing tool 500 and returned to cassette 120, controller 113, for example via gateway 119, may control table / stage 112 to unload wafer carrier 120 from storage buffer 111.

[0027] In some embodiments, after the wafer carrier 120 is unloaded from the storage buffer 111 to the table / stage 112, the door opening / closing mechanism 116 is configured to remove the door from the door storage system 118. The removed door may be the original door 122 of the wafer carrier 120 before the wafer carrier 120 was loaded into the storage buffer 111, or may be another door of the same model or type as the original door 122 that fits the wafer carrier 120. In practice, the door opening / closing mechanism 116 may hold the removed door from the corresponding door storage section, move it down (i.e., along the -Z direction), and reinstall and / or close the removed door on the wafer carrier 120, e.g., by a latch key and a vacuum hole. The OHT system may then unload the reclosed wafer carrier 120 from the table / stage 112 and transport it, e.g., to another load port or tool, for further processing of one or more semiconductor wafers in the wafer carrier 120.

[0028] In some embodiments, the multi-cassette storage buffer 111 of the MCLP device 110 may include a plurality of buffer spaces moveably mounted in the storage buffer 111, for example, via a suitable elevator or other similar mechanism. To load a wafer carrier, the controller 113 may first control the plurality of buffer spaces to selectively move up or down (i.e., along the Z or −Z direction) such that an unoccupied one of the buffer spaces is aligned with the table / stage 112 and / or the gateway 119. The controller 113 may then control the table / stage 112 to move the wafer carrier 120 into the aligned buffer space (i.e., along the −X direction) via the gateway 119 to load the wafer carrier into the aligned buffer space of the storage buffer 111.

[0029] For one or more opened cassettes loaded into the storage buffer 111 (i.e., cassettes whose doors have been opened / removed and buffered / stored in multiple buffer spaces of the storage buffer 111), the EFEM 300 coupled to the MCLP device 110 may selectively remove and return wafers in sequence.

[0030] For a wafer carrier unloaded from the MCLP device 110, after the tool 500 has finished processing one or more wafers in sequence and the one or more wafers are returned (e.g., by the EFEM 300) to the released wafer carrier 120 in the storage buffer 111, the controller 113 may control the table / stage 112 to unload the wafer carrier 120 from the buffer space via the gateway 119. In practice, at any given time (e.g., during the waiting time for wafer processing), there may be multiple wafer carriers 120 stored and / or buffered in the buffer space of the storage buffer 111, so that the previously aligned buffer space may be misaligned with the table / stage 112 and / or the gateway 119. In this case, the controller 113 may first control the buffer space to selectively move up or down to realign the previously aligned buffer space with the table / stage 112 and / or the gateway 119, and then control the table / stage 112 to unload the wafer carrier 120 from the realigned buffer space.

[0031] 1, a storage buffer 111 including multiple buffer spaces is located behind wafer carrier 120 from an operator's perspective when the operator is standing in front of MCLP device 110 and facing door storage system 118. In this case, table / stage 112 is configured to move wafer carrier 120 from the operator's perspective from front to back into the buffer spaces.

[0032] FIG. 2A illustrates a front perspective view of another MCLP device 110 according to some embodiments of the present disclosure. FIG. 2B illustrates a corresponding rear perspective view of the MCLP device 110 illustrated in FIG. 2A. In general, the MCLP device 110 illustrated in FIGS. 2A and 2B has a corresponding arrangement of parts, components, and / or elements similar to that illustrated in FIG. 1 and operates in essentially the same manner as described above or elsewhere. However, the arrangement of the MCLP device 110 illustrated in FIGS. 2A and 2B differs from the arrangement illustrated in FIG. 1. That is, the MCLP device 110 in FIGS. 2A and 2B can be considered a side-loading MCLP device 110 (i.e., from the operator's perspective) and the MCLP device 110 in FIG. 1 can be considered a front-loading MCLP device 110 (i.e., from the operator's perspective).

[0033] As shown in Figures 2A and 2B, the table / stage 112 is configured to receive a wafer carrier 120 having a door (not shown in Figures 2A and 2B) on a side that faces the rear of the wafer carrier 120, i.e., the door storage system 118. The door storage system 118 and door opening mechanism 116 in this embodiment extend from and / or are coupled to a corner of the housing of the storage buffer 111, i.e., the left rear corner (as viewed in Figure 2A) of the storage buffer 111, and extend therefrom generally in an X-direction relative to the storage buffer 111. In this case, the door opening mechanism 116 is configured to open and / or remove the door of the wafer carrier 120 (e.g., by means of a latch key and a vacuum hole) and move the door towards the rear of the wafer carrier 120 and away from the wafer carrier 120 (i.e., along the -Y direction as shown in Figures 2A and 2B). The door opening / closing mechanism 116 then holds the door and moves it up along the Z direction to the door storage system 118 where the door is selectively stored in the door storage section while the cassette 120 is loaded into the storage buffer 111.

[0034] In this embodiment, gateway 119 to storage buffer 111 is disposed on the left side of the storage buffer 111 housing (as viewed from the perspective of FIG. 2A ) and faces the right side of wafer carrier 120. Thus, in this embodiment, table / stage 112 is configured to selectively move cassette 120 laterally (i.e., in the −X and / or X directions), e.g., under the direction and / or control of controller 113, to load cassette 120 into and / or remove cassette 120 from the aligned buffer space of storage buffer 111.

[0035] In the embodiment of Figures 2A and 2B, the EFEM 300 may be coupled to the rear or back side of the MCLP apparatus 110 to selectively remove / return wafers from / to the wafer carrier 120 stored in the door storage system 118 (through an opening in the rear or back side of the storage buffer 111) when the door is opened / removed while the wafer carrier 120 is loaded and / or present in the buffer space 117 of the storage buffer 111.

[0036] According to the embodiment shown in Figures 2A and 2B, the storage buffer 111 including the multiple buffer spaces 117 is located to the right of the wafer carrier 120 (as seen in Figure 2A) from an operator's perspective when the operator is standing in front of the MCLP apparatus 110 and facing the door storage system 118. In this case, the table / stage 112 is configured to selectively move the wafer carrier 120 into the aligned buffer spaces 117 from left to right from the operator's perspective via the gateway 119 for loading. Alternatively, it will be appreciated that in some embodiments, the storage buffer 111 of the MCLP apparatus 110 including the buffer spaces may be located to the left of the wafer carrier 120, and the table / stage 112 may be configured to selectively move the wafer carrier 120 into the aligned buffer spaces from right to left from the operator's perspective for loading. That is, in some embodiments, the MCLP apparatus 110 may be configured and / or arranged essentially as a mirror image of that shown in Figures 2A and 2B.

[0037] 3, a dolly 200 of the OHT system selectively delivers and retrieves cassettes 120 to and from the table / stage 112 of the MCLP machine 110. In the illustrated embodiment, the storage buffer 111 of the MCLP machine 110 is shown loaded with multiple cassettes 120a, 120b, 120c, 120d. Although four cassettes are illustrated for purposes of this example, in practice the storage buffer 111 may accommodate more or less than four cassettes.

[0038] In some embodiments, the EFEM 300 is coupled to the MCLP apparatus 110 such that the robot 302 of the EFEM 300 may selectively remove and return a selected wafer 400 to a selected cassette in the storage buffer 111 in a sequential order. As an example, the robot 302 of the EFEM 300 is shown removing the wafer 400 from cassette 120b. After removing the wafer 400, the EFEM 300 (e.g., via the robot 302) transfers and / or places the wafer 400 into the chamber 502 of the tool 500. After processing, testing, and / or inspection of the wafer 400 is completed by the tool 500, the EFEM 300 removes the wafer 400 from the chamber 502 of the tool 500 and returns the wafer 400 to its cassette in the storage buffer 111 of the MCLP apparatus 110.

[0039] Generally, the EFEM 300 is provided, programmed, or otherwise supplied with position information and / or data (i.e., referred to herein as reference wafer position data) indicative of an expected reference position of the wafer 400. In some embodiments, the EFEM 300 and / or the robot 302 use, at least in part, the reference wafer position data to precisely retrieve the wafer 400 from its respective cassette in the storage buffer 111 and to precisely deliver and / or place the wafer 400 in the chamber 502 of the tool 500.

[0040] However, in reality, the wafer 400 may not exactly match or be at the reference position indicated by the reference wafer position data. That is, in reality, the actual wafer position may change from the reference wafer position from time to time. For example, in reality, during various transport steps, the wafer 400 may actually laterally deviate in a certain direction (e.g., in the XY plane or horizontal plane) from the reference position. For example, such deviation may occur in the wafer 400 when the tolerances or other similar tolerances in the dimensions and / or configurations of the cassettes that accommodate the wafer 400 do not strictly limit or precisely fix the position of the wafer 400 in the respective cassettes. In addition, bowing of the wafer 400, which occurs naturally or otherwise, may cause the wafer 400 (or a bowed portion thereof) to not exactly match the reference position in the vertical direction (i.e., in the direction of the Z axis). That is, if the wafer 400 (or a bowed portion thereof) is not strictly flat, the effective height or vertical position (e.g., in the Z direction) above the surface of the wafer may differ from the corresponding reference position. Therefore, using only the reference wafer position data to constrain the wafer handled by EFEM 300 may result in misalignments that may cause damage to the wafer handled by EFEM 300, for example, when loading and / or placing wafer 400 into chamber 502 of tool 500.

[0041] Thus, in accordance with certain embodiments disclosed herein, the MCLP tool 110 is supplied, equipped, and / or configured with a compensation system that transmits or provides wafer position offset data to the EFEM 300, which (along with reference wafer position data) is then used by the EFEM 300 to calculate, correct, and / or compensate for deviations of the wafer from the reference wafer position, e.g., by limiting handling of the wafer by the robot 302, to avoid potential misalignments.

[0042] 3, the compensation system includes a wafer position sensor 600 that measures and / or detects the position or location of a semiconductor wafer 400. In some embodiments, the sensor 600 is located, contained, or disposed within the storage buffer 111 of the MCLP device 110 (i.e., within the housing of the storage buffer 111, see FIG. 4) so ​​as not to increase the overall collective footprint of the tools and / or equipment on the FAB floor.

[0043] In practice, the wafer position sensor 600 is an optical sensor positioned and / or located toward the top of the storage buffer 111 (i.e., in the Z direction) and pointed, pointed, or oriented vertically downward, e.g., perpendicular to the horizontal plane and / or transport path of the wafer 400 (i.e., perpendicular to the XY plane in the illustrated embodiment), to image the wafer 400 within its field of view (FoV). In some embodiments, the sensor 600 may be oriented plus or minus 30° from vertical to allow flexibility in the design of the MCLP apparatus 110 and / or flexibility in the placement of the sensor 600 within the storage buffer 111. The sensor 600 is positioned, pointed, and / or oriented with its FoV 602 interposed between the open door side of the cassettes 120a, 120b, 120c, 120d held in the storage buffer 111 and the EFEM 300 and / or its robot 302.

[0044] In some embodiments, the sensor 600 acquires three-dimensional (3D) position information and / or data based on a measured or detected position of the wafer 400 within the FoV 602. In some embodiments, the position sensor 600 is an optical sensor (e.g., employing a camera, a raster laser beam, a linear array of light emitting diodes (LEDs) or laser diodes, various combinations thereof, etc.). For example, the optical wafer position sensor may be a machine vision (MV) sensor and may include any one or more of an area camera, a pair of stereo vision cameras, a line scanner, and / or a laser displacement sensor. For example, in some embodiments, the area camera may acquire or capture a two-dimensional (2D) image of the entire wafer 400 within the FoV 602. In some other embodiments, a line scanner may acquire or capture a 2D image of the wafer 400 line by line as the wafer 400 passes through the FoV 602. In some embodiments, it is preferred that a laser displacement sensor measures or detects the depth or displacement (e.g., along the Z direction) of the wafer 400, for example using measurements of the time-of-flight interval of a pulsed laser or the coherent optical phase shift of reflected light, from which a corresponding surface profile or depth map is at least partially created or derived. In some other embodiments, the sensor 600 may employ a pair of stereo vision cameras from which 3D images are acquired. In some embodiments, the sensor 600 may include various combinations of any one or more of the above configurations to obtain 3D measurements and / or detections of the wafer position or location.

[0045] In some embodiments, the amount and / or direction of wafer bow (i.e., bow of wafer 400 in Z and / or −Z directions) and / or the amount and / or direction of wafer misalignment (i.e., misalignment of wafer 400 along a direction in the XY plane) is calculated based on and / or is based at least in part on information and / or data imaged and / or acquired by position sensor 600. For example, the bow or misalignment of wafer 400 from a reference position may be calculated, at least in part, from 3D position data and / or information acquired by position sensor 600. In some preferred embodiments, a wafer bow of about 1000 μm or more may be detected and / or calculated. In some preferred embodiments, a wafer misalignment of about 0.5 mm or more may be detected and / or calculated.

[0046] In some embodiments, the calculated or otherwise acquired bow and / or misalignment of the wafer 400 (which accounts for potential differences in the wafer position and / or location relative to, for example, an expected reference wafer position and / or location) is then converted to or used to derive the wafer position offset data described above that is transmitted and / or provided to the EFEM 300. In some embodiments, this conversion and / or derivation provides the wafer position offset data in a coordinate system known and / or used by the EFEM 300. In some preferred embodiments, the received wafer position offset data is used, at least in part, by the EFEM 300 to further limit or control the movement of the robot 302 handling the wafer 400, thereby avoiding potential misalignments that could cause damage to the wafer 400, for example, when the robot 302 loads and / or places the wafer 400 in the chamber 502 of the tool 500. That is, the wafer position offset data is used by the EFEM 300 to calculate, correct, and / or compensate for wafer deviations from a reference wafer position, for example, to limit and / or control the handling of the wafer by the robot 302.

[0047] 4, an advantage of the disclosed approach in which the optical wafer position sensor 600 is located within the MCLP tool 110 is that the footprint of the setup is reduced. In this regard, while schematic FIG. 4 shows the optical wafer position sensor 600 for illustrative purposes, in a real setup the sensor 600 may be located inside the MCLP tool 110 (as shown in schematic FIG. 3) and therefore may be obscured from view. As seen in the perspective view of FIG. 4, the FoV 602 where the optical measurement of the wafer position is made may also be located inside the MCLP tool 110. In this arrangement, the wafer position (e.g., lateral shift and / or bow) is measured before the wafer is handled by the robot 302 and placed in the tool 500 (see FIG. 3). By communicating wafer position information to the robot 302 or other wafer handling equipment (more generally, the EFEM 300) prior to complex wafer handling, the robot 302 can be programmed to accommodate for wafer misalignment and / or bow to ensure precise placement of the wafer within the tool 500, thereby improving wafer handling accuracy and reducing the chance of wafer damage due to misalignment by the robot 302.

[0048] Referring to FIG. 5, the illustrated flow diagram illustrates a method and / or process 700 according to some embodiments disclosed herein, such as may be performed by the compensation system described above.

[0049] As shown, in step 702 , a sensor 600 measures or detects the 3D position of a wafer 400 within a FoV 602 .

[0050] As shown, in step 704, the bow and / or shift of wafer 400 (e.g., describing or reflecting bow (e.g., in the Z and / or -Z directions) and / or shift (e.g., in the XY plane) from a reference wafer position or location) is calculated or otherwise determined, at least in part, using, from, and / or based on the measurements obtained in step 702.

[0051] As shown, in step 706, wafer position offset data is calculated or determined, at least in part, using, from and / or based on the bow and / or misalignment arrived at in step 704. The wafer position offset data preferably accounts for or reflects the bow and / or misalignment of the wafer 400 from a reference wafer position as expected by the EFEM 300 in a coordinate system known and / or used by the EFEM 300.

[0052] As shown, in step 708 , wafer position offset data is transmitted or provided to the EFEM 300 .

[0053] As shown, in step 710, the EFEM 300 limits and / or controls the handling of the wafer 400 by the robot 302 using, at least in part, the received wafer position offset data, e.g., to load and / or place the wafer 400 into a chamber of the tool.

[0054] Measuring both the lateral displacement and bow 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, thereby providing maximum information for adjusting the handling of the wafer by the EFEM 300. However, in certain situations, only the lateral displacement or only the bow is measured. An example of a situation in which bow measurement is omitted is when early in the manufacturing process, the wafer may have few or no deposited layers. Bow is often due to deposition of different materials on the wafer (e.g., due to different thermal expansion between the deposited material and silicon or other wafer materials, or in the case of epitaxial deposition, e.g., due to lattice mismatch), and it may not be necessary to measure the bow of the wafer when transferring the wafer early in the manufacturing process. Similarly, if the wafer diameter is small, bow may be considered negligible. An example of a situation in which lateral displacement measurement is omitted is when the robot 302 and tool 500 are designed to tolerate significant wafer offsets, and offset errors are unlikely to cause problems.

[0055] In some embodiments, the controller 113 may be in operative communication with the sensor 600 and the EFEM 300 and may be programmed or otherwise provided to implement the functions performed by the compensation system and / or to execute the process 700. In some other embodiments, the compensation system may use a separate controller. In some embodiments, the compensation system controller may be housed remotely or elsewhere, for example, outside the MCLP device 110.

[0056] In some embodiments, the controller 113 and / or the compensation system controller may be implemented by hardware, software, or a combination thereof. In particular, one or more controllers may be embodied by a processor, electronic circuit, computer, and / or other electronic data processing device configured or provided to perform one or more tasks, steps, processes, methods, and / or functions described herein. For example, a processor, computer, server, or other electronic data processing device embodying a controller may be provided, supplied, and / or programmed with a listing of suitable code (e.g., source code, interpreted code, object code, directly executable code, etc.) or other similar instructions or software or firmware that, when run and / or executed by a computer or other electronic data processing device, completes or performs one or more tasks, steps, processes, methods, and / or functions described herein. The code listing or other similar instructions or software or firmware is preferably 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 such that it can be provided to and / or executed by a computer or other electronic data processing device. For example, suitable storage media and / or media may include, but are not limited to, floppy disks, flexible disks, hard disks, magnetic tapes or other magnetic storage media or media, CD-ROMs, DVDs, optical disks or other optical media or media, RAM, ROM, PROMs, EPROMs, FLASH-EPROMs or other memory, chips, cartridges or other tangible media that can be read and used by a computer or machine or electronic data processing device. In essence, as used herein, non-transitory computer readable and / or machine readable medium and / or media includes all computer readable and / or machine readable media and / or media, except for transitory propagating signals.

[0057] In general, any one or more of the specific tasks, steps, processes, methods, functions, elements, and / or components described herein may be implemented and / or embodied in one or more general purpose computers, application specific computers, programmed microprocessors or microcontrollers and peripheral integrated circuit elements, hardwired electronic or logic circuitry such as ASICs or other integrated circuits, digital signal processors, discrete element circuits, programmable logic devices such as PLDs, PLAs, FPGAs, graphic card CPUs (GPUs), or PALs, etc. In general, any device capable of implementing a finite state machine that is in turn capable of implementing the respective tasks, steps, processes, methods, and / or functions described herein may be used.

[0058] Below some further exemplary embodiments are described.

[0059] In some embodiments, a wafer handling method for handling semiconductor wafers in a space of a semiconductor wafer processing facility includes loading a cassette containing at least one semiconductor wafer into a storage buffer of a load port, measuring a position of at least one selected semiconductor wafer removed from the cassette present in the storage buffer from within the storage buffer using an optical sensor provided in the storage buffer, and determining a difference in position of the selected semiconductor wafer from a reference position based at least in part on the measurement.

[0060] In some embodiments, the wafer handling method further includes communicating the determined differences to an EFEM coupled to the load port, where the EFEM controls handling of the selected semiconductor wafer based at least in part on the determined differences.

[0061] In yet an additional embodiment, the difference includes a difference in a position of the selected semiconductor wafer from a reference position in at least three dimensions.

[0062] In some embodiments, the determining includes at least one of determining a bow of the selected semiconductor wafer in a first direction and determining a shift of the selected semiconductor wafer in a second direction in a plane perpendicular to the first direction.

[0063] In yet a further embodiment, the wafer handling method further includes converting the determined difference into wafer position offset data and transmitting the wafer position offset data to an EFEM, where the EFEM controls handling of the selected semiconductor wafer based at least in part on the wafer position offset data.

[0064] In some further embodiments, the position offset data expresses the determined difference in a coordinate system recognized by the EFEM.

[0065] In some embodiments, the measurements are performed by a machine vision sensor housed within a storage buffer of the load port.

[0066] In yet a further embodiment, the machine vision sensor includes at least one of an area camera, a pair of stereo cameras, a line scanner, and a laser displacement sensor.

[0067] In some embodiments, the machine vision sensor is oriented perpendicular to the path of travel followed by a selected semiconductor wafer as it is removed from the cassette.

[0068] In some further embodiments, the machine vision sensor is oriented within plus or minus 30 degrees of normal to the path of travel followed by a selected semiconductor wafer as it is removed from the cassette.

[0069] In yet a further embodiment, the machine vision sensor has a field of view interposed between a cassette loaded in a storage buffer of the load port and a robot of an EFEM coupled to the load port for transporting a selected semiconductor wafer to a chamber of a tool where the selected semiconductor wafer is processed.

[0070] In yet an additional embodiment, a wafer handling method is provided as a compensation method for semiconductor wafers whose positions differ from an expected reference position, the wafer handling method including: holding at least one cassette containing at least one semiconductor wafer in a storage buffer, detecting within the storage buffer a position of at least one selected semiconductor wafer removed from the at least one cassette held in the storage buffer, and determining a difference of the selected semiconductor wafer from a reference position based at least in part on the detected position.

[0071] In some further embodiments, the determining includes determining a first difference in the selected semiconductor wafer in a first direction and determining a second difference in the selected semiconductor wafer in a second direction in a plane perpendicular to the first direction.

[0072] In some additional embodiments, the wafer handling method further includes determining wafer position offset data based at least in part on the first and second differences.

[0073] In some embodiments, the wafer handling method further includes transmitting wafer position offset data to an EFEM, where after the EFEM receives the wafer position offset data, the EFEM controls handling of the selected semiconductor wafer by a robot based at least in part on the received wafer position offset data.

[0074] In some embodiments, the detection is performed by a sensor having a field of view interposed between the robot and at least one cassette held in the storage buffer.

[0075] In some further embodiments, the sensor is contained within a storage buffer.

[0076] In yet a further embodiment, a load port for staging semiconductor wafers includes a storage buffer for holding at least one cassette, at least one cassette housing at least one semiconductor wafer, and a sensor housed within the storage buffer for detecting a position of at least one selected semiconductor wafer removed by a robot from the at least one cassette, and a difference in position of the selected semiconductor wafer from a reference position is preferably determined by the load port based at least in part on the position detected by the sensor.

[0077] In yet a further embodiment, the position detected by the sensor is a three-dimensional position.

[0078] Further, in one or more embodiments, the at least one cassette includes a plurality of cassettes, the storage buffer includes a plurality of buffer spaces each accommodating one of the plurality of cassettes, and the storage buffer selectively moves the plurality of buffer spaces to align a selected one of the plurality of buffer spaces with a gateway through which the cassettes are selectively loaded into the storage buffer.

[0079] The foregoing outlines features of some embodiments so that those skilled in the art may more easily understand aspects of the present disclosure. Those skilled in the art should appreciate that this disclosure may be readily used as a basis for designing or modifying other processes and structures to carry out the same purposes and / or achieve the same advantages as the embodiments presented herein. Those skilled in the art should also appreciate that such equivalent structures do not depart from the spirit and scope of the present disclosure, and that various modifications, substitutions, and alterations may be made without departing from the spirit and scope of the present disclosure. [Industrial Applicability]

[0080] The wafer handling method and load port of the present disclosure may be applied in different fields such as mechanical parts, semiconductor devices, electronic parts, and automotive industries, and can be widely used in various applications such as the manufacture of integrated circuits including semiconductor devices. [Explanation of symbols]

[0081] 110:MCLP device 111: Storage buffer 112: Table / Stage 113: Controller 116: Door opening and closing mechanism 116H: Vacuum hole 116K: Latch key 117: Buffer space 118: Door storage system 119: Gateway 120: Wafer carrier / cassette 120a, 120b, 120c, 120d: Cassette 122: Door 200: Cart 300:EFEM 302:Robot 400: Wafer 500: Tools 502: Chamber 600: Sensor 602: Field of view (FoV) 700: Processing 702, 704, 706, 708, 710: Process

Claims

1. 1. A method for handling semiconductor wafers in a space of a semiconductor wafer processing facility, comprising: loading a cassette containing at least one semiconductor wafer into a storage buffer of a load port; measuring a position of at least one selected semiconductor wafer removed from the cassette present in the storage buffer from within the storage buffer using an optical sensor provided in the storage buffer; determining a difference in a position of the selected semiconductor wafer from a reference position based at least in part on the measurements; Including, The determining step comprises: determining a bow of the selected semiconductor wafer in a first direction; determining a lateral displacement of the selected semiconductor wafer in a second direction in a plane perpendicular to the first direction. Wafer handling methods.

2. 2. The wafer handling method of claim 1, further comprising communicating the determined differences to an equipment front-end module (EFEM) coupled to the load port, the equipment front-end module controlling handling of the selected semiconductor wafer based at least in part on the determined differences.

3. 2. The wafer handling method of claim 1, further comprising: converting the determined difference into wafer position offset data; and transmitting the wafer position offset data to an equipment front-end module (EFEM), wherein the equipment front-end module controls handling of the selected semiconductor wafer based at least in part on the wafer position offset data.

4. The wafer handling method of claim 1 , wherein the measurements are performed by a machine vision sensor housed within the storage buffer of the load port.

5. 5. The wafer handling method of claim 4, wherein the machine vision sensor has a field of view interposed between the cassette loaded in the storage buffer of the load port and a robot of an equipment front end module (EFEM) coupled to the load port for transporting the selected semiconductor wafer to a chamber of a tool where the selected semiconductor wafer is processed.

6. 1. A method of compensation for a semiconductor wafer whose position differs from an expected reference position, comprising: maintaining at least one cassette containing at least one semiconductor wafer in a storage buffer; detecting a position within the storage buffer of at least one selected semiconductor wafer to be removed from the at least one cassette held in the storage buffer; determining a difference of the selected semiconductor wafer from the reference position based at least in part on the detected position; and Including, The determining step comprises: determining a bow of the selected semiconductor wafer in a first direction; determining a lateral displacement of the selected semiconductor wafer in a second direction in a plane perpendicular to the first direction. Wafer handling methods.

7. 7. The wafer handling method of claim 6, further comprising: transmitting wafer position offset data to an equipment front-end module (EFEM), wherein after the equipment front-end module receives the wafer position offset data, the equipment front-end module controls handling of the selected semiconductor wafer by a robot based at least in part on the received wafer position offset data.

8. 8. The wafer handling method of claim 7, wherein said detection is performed by an optical sensor having a field of view interposed between said at least one cassette held in said storage buffer and said robot.

9. 1. A load port for staging semiconductor wafers, comprising: a storage buffer for holding at least one cassette containing at least one semiconductor wafer; a sensor included in the storage buffer that detects a position of at least one semiconductor wafer being removed by a robot from the at least one cassette; Including, a difference in position of the selected semiconductor wafer from a reference position is determined by the load port based at least in part on the position detected by the sensor; The determination is determining a bow of the selected semiconductor wafer in a first direction; determining a lateral displacement of the selected semiconductor wafer in a second direction in a plane perpendicular to the first direction. Loading port.

10. the at least one cassette comprises a plurality of cassettes; the storage buffer includes a plurality of buffer spaces, each of the buffer spaces housing one of the plurality of cassettes; 10. The load port of claim 9, wherein the storage buffer is configured to selectively move a selected one of the buffer spaces to align with a gateway, and wherein the cassette is selectively loaded into the storage buffer via the gateway.

Images