Multi-holder inspection system using movable support structure

Abstract

An ultrasonic inspection system includes an ultrasonic scanning station, a support structure, and two or more object holders coupled to the support structure. The support structure is movable between first and second orientations. The object holder enables holding of an object for ultrasonic scanning. In a first orientation of the support structure, the first object holder is to be held in an ultrasonic scanning station and the second object holder is positioned to allow loading or unloading. In the second orientation, the second object holder is positioned in the ultrasonic scanning station, and the first object holder is positioned to allow loading or unloading. The object holder may be raised above the water level for loading / unloading, and lowered below the water level for ultrasonic inspection. The object holder may have a wafer lifter to hold the semiconductor wafer over the object holder for automated handling.

Description

[0001] Related applications This application claims the benefit of provisional application serial number 63 / 456,706, filed April 3, 2023, entitled “Multi-chuck Inspection System”, and non-provisional application serial number 18 / 624,537, filed April 2, 2024, entitled “Multi-Holder Inspection System Using Moveable Support Structure”, the entire contents of which are incorporated herein by reference. Background Technology

[0002] Ultrasonic inspection equipment is used to perform non-destructive testing (NDT) on semiconductor wafers or packages to detect potential quality issues or manufacturing defects. Semiconductor manufacturers are constantly seeking to reduce inspection time in order to increase productivity in the production process. Therefore, there is a need to reduce inspection time to improve productivity.

[0003] Currently available ultrasonic inspection equipment features one or more fixed wafer chucks with a long scan axis motor assembly or two separate assemblies to perform scans. Each wafer chuck can provide one or more ultrasonic transducers to reduce the overall scan time. These systems provide increased throughput by scanning multiple wafers in parallel. However, throughput is still limited by the transition time between scans. Currently available equipment exhibits a significant delay in removing the previous wafer from the wafer chuck and placing the new wafer on it before the next scan can begin. Attached Figure Description

[0004] The accompanying drawings provide visual representations that will be used to more fully describe various representative embodiments and can be used by those skilled in the art to better understand the disclosed representative embodiments and their inherent advantages. In these drawings, the same reference numerals denote corresponding or similar elements.

[0005] Figure 1 An ultrasonic inspection system according to various representative embodiments is shown.

[0006] Figure 2 and Figure 3 An exemplary scanner of an inspection system according to various representative embodiments is illustrated.

[0007] Figure 4 A scanner for an ultrasonic inspection system according to various representative embodiments is shown.

[0008] Figure 5 A wafer chuck assembly with a highly adjustable wafer chuck is shown according to various representative embodiments.

[0009] Figure 6 and Figure 7 A scanner of an inspection system according to various representative embodiments is shown.

[0010] Figure 8 A wafer chuck assembly with a highly adjustable wafer chuck is shown according to various representative embodiments.

[0011] Figure 9 This is a flowchart of an ultrasound examination method according to various representative embodiments.

[0012] Figure 10 The image shows a wafer without attached grains.

[0013] Figure 11 A wafer with attached grains is shown.

[0014] Figure 12A and Figure 12B A wafer chuck with a wafer lifter mechanism is shown according to various representative embodiments.

[0015] Figure 13 A side view of a wafer chuck with a wafer lifter mechanism according to various representative embodiments is shown.

[0016] Figure 14A and Figure 14B Other views are of a wafer chuck with a wafer booster mechanism according to various representative embodiments.

[0017] Figure 15 A side view of a wafer chuck with a wafer lifter mechanism according to various representative embodiments is shown.

[0018] Figure 16 The illustrations illustrate the working principle of wafer disposal according to various representative embodiments.

[0019] Figure 17 This is a flowchart of an operation method for a wafer chuck with a wafer booster according to various representative embodiments. Detailed Implementation

[0020] The various devices and apparatuses described herein relate to test and measurement systems, and more specifically, to inspection systems, such as systems for ultrasonic inspection of devices under test (DUTs), and inspection methods.

[0021] While this disclosure allows for many different forms of embodiments, specific embodiments are shown in the accompanying drawings and will be described in detail herein. It should be understood that the embodiments shown and described herein should be considered as examples providing the principles of this disclosure and are not intended to limit this disclosure to the specific embodiments shown and described. In the following description, the same reference numerals are used to describe the same, similar, or corresponding portions in several views of the drawings. For simplicity and clarity of illustration, reference numerals may be repeated in the drawings to indicate corresponding or similar elements.

[0022] Current systems for ultrasonic inspection of semiconductor wafers exhibit significant delays in removing previous wafers from the wafer chucks used for inspection and placing new wafers on the chucks before a subsequent scan can begin. In addition to minimizing scan time, the various systems disclosed herein increase throughput by minimizing transition time between scans.

[0023] Embodiments of this disclosure include a multi-chuck platform capable of handling more than two wafer chucks and an integrated support structure (e.g., an indexing stage or rotary stage) for seamless wafer / package handling and scanning. This significantly increases throughput by loading, aligning, and queuing the next wafer or package while the previous inspection is in progress.

[0024] Various embodiments provide an ultrasonic inspection system including one or more ultrasonic scanning stations, one or more support structures, and a plurality of object holders coupled to the support structures. For example, the support structure may be movable, such as a rotatable indexing stage. Each object holder is configured to hold an object for ultrasonic scanning. Each support structure is movable and may be rotatable between a first orientation and a second orientation. In the first orientation of the support structure, a first object holder is positioned to allow loading or unloading of the first object holder, and a second object holder is positioned in one of the one or more ultrasonic scanning stations. In the second orientation of the support structure, a second object holder is positioned to allow loading or unloading of the second object holder, and a first object holder is positioned in the ultrasonic scanning station. The object holder may be a wafer chuck configured to hold a semiconductor wafer for ultrasonic scanning.

[0025] An ultrasonic scanning station includes an ultrasonic transducer. In one embodiment, a water coupler is used to couple ultrasonic waves from the transducer to an object. In another embodiment, the ultrasonic inspection system includes a scanning tank for containing water. In this embodiment, ultrasonic waves are coupled to the object by immersing the transducer and the object in the water tank. In some embodiments, the scanning station may use other scanning devices and / or other scanning techniques.

[0026] In some embodiments, the object may be held in a scanning tank for ultrasonic inspection. The object holder may be coupled to a support structure via a mechanism for moving the held object between a first position above the water in the scanning tank (for loading and unloading) and a second position immersed in the water in the scanning tank (for ultrasonic scanning). The object holder is coupled to the support structure via three actuators configured to adjust the orientation of the object holder within the ultrasonic scanning station.

[0027] The wafer chuck of the ultrasonic inspection system may include a wafer lifter located in the peripheral region of the wafer chuck. The wafer lifter can be raised to support the semiconductor wafer in a first position above the wafer chuck, allowing a robotic arm to pass between the wafer chuck and the underside of the semiconductor wafer. The wafer lifter can be lowered to a second position below the first position, allowing the semiconductor wafer to pass under the support of the wafer chuck.

[0028] Various embodiments provide a method of operating an ultrasonic inspection system, comprising: moving (i.e., rotating) a support structure to a first orientation, wherein a first object holder coupled to the support structure is located outside an ultrasonic scanning station of the ultrasonic inspection system, and a second object holder coupled to the support structure is located within the ultrasonic scanning station; performing an ultrasonic scan of an object in the second object holder; unloading a previously scanned object from the first object holder; loading an object from a plurality of objects to be scanned into the first object holder; moving (i.e., rotating) the support structure to a second orientation, wherein the first object holder is located within the ultrasonic scanning station, and the second object holder is located outside the ultrasonic scanning station; performing an ultrasonic scan of the object in the first object holder; unloading a previously scanned object from the second object holder; and loading an object to be scanned into the second object holder.

[0029] Embodiments may include raising the first object holder outward from the tank to unload a previously scanned object from the first object holder; lowering the first object holder into the tank to scan the object in the first object holder; raising the second object holder outward from the tank to unload a previously scanned object from the second object holder; and lowering the second object holder into the tank to scan the object in the second object holder. In one embodiment, the object holder is raised and lowered when positioned for loading and unloading. However, in general, the object holder can be raised or lowered in any orientation of the supporting structure.

[0030] The embodiment may include raising a wafer lifter located in the peripheral area of ​​the wafer chuck, placing the semiconductor wafer on the lifter using a robotic positioning arm positioned between the lower surface of the semiconductor wafer and the upper surface of the wafer chuck; retracting the robotic positioning arm; and lowering the wafer lifter to place the lower side of the semiconductor wafer on the upper surface of the wafer chuck.

[0031] Figure 1 An ultrasonic inspection system 100 according to various representative embodiments is illustrated. A scanner 102, located in a housing 104, is the core processing module of the system and performs wafer / package inspection. The housing 104 also includes a robotic module 106 for wafer handling, an electrical, piping, and computer control panel 108, and an air filter 110. A user interface 112 is also provided. Between scans, the previous wafer is removed from the chuck, and the next wafer is loaded. Embodiments of this disclosure minimize the waiting time between scans by integrating a rotatable chuck support structure (e.g., an indexing table or a rotary stage) into the scanner's scan slot.

[0032] The present disclosure is described below with reference to semiconductor wafer chucks. Wafer chucks are typically used to support semiconductor wafers during inspection processes. A wafer can be held on a wafer chuck by creating a vacuum between the wafer and the surface of the wafer chuck. However, it should be appreciated that in some embodiments, other types of object holders can be used instead of wafer chucks. An object holder can be any holding mechanism that supports a wafer, tray, package, or other object or device under test. These methods are not specific to semiconductor wafers and packages and can be used for any sample type.

[0033] Furthermore, this disclosure is described below with reference to a moving or rotating indexing table or a rotary stage. However, various support structures can be used instead of a rotary indexing table. For example, each object holder can be supported by a rotatable arm, wherein two or more arms are coupled to a central pivot to form a support structure.

[0034] Ultrasonic inspection equipment with four wafer chucks in a single rotary stage Figure 2 and Figure 3 An exemplary scanner 200 of an inspection system according to various representative embodiments is illustrated. Figure 2 In the exemplary embodiment shown, scanner 200 is constructed around scan slot 202. Support structure 204 is a movable rotary indexing stage (rotary platform) located within scan slot. Support structure 204 is configured for four wafer chucks and their corresponding wafers. Two wafer chucks 206 are positioned for scanning below ultrasonic transducers 208 of the ultrasonic scanning station, while two wafer chucks 210 are positioned to allow loading and unloading of wafers. The scanning station is the area of ​​scanner 200 that holds objects for inspection. Figure 2The diagram shows two scanning stations, each including an ultrasonic transducer 208, a transducer mount 212 holding the ultrasonic transducer, and a pusher assembly 216. The pusher assembly 216 is mounted on a scanning bridge 218 and moves the ultrasonic transducer along a scanning axis direction 214 to scan the wafer in the ultrasonic scanning station. The pusher assembly 216 may be able to move independently of each other. The scanning station may also include a water coupler that supplies water to acoustically couple the ultrasonic waves generated by the transducers to the object under test.

[0035] Figure 3 This is a top view of the scanner 200 according to various representative embodiments. A raster scan of the wafer in the wafer chuck 206 is achieved by moving the transducer 208 in the scan axis direction 214 and the scan bridge 218 along the step axis side rail 304 in the step axis direction 302. The wafer chuck 210 is used for loading and unloading wafers. The support structure 204 can be rotated 180° using a motorized rotating spindle 306. Sample wafers or packages can be automatically placed on the wafer chuck 210 using an atmospheric robot or manually by an operator. Once the wafer or package is loaded onto the wafer chuck 210, the system rotates the support structure 204 180° to position the sample in the ultrasonic scanning station for inspection. The scanning process then begins to inspect the sample on the wafer chuck 210. Simultaneously, the wafer chuck 206, now rotated out of the scanning station, is loaded with a new sample. Once the inspection of the sample on wafer chuck 210 is complete, the support structure 204 rotates 180° back to its original position to allow the sample to be unloaded. While unloading the inspected sample from wafer chuck 210 and loading a new sample into it, the scanner can simultaneously begin inspecting the sample on wafer chuck 206. This process minimizes downtime between scans by preparing the next sample in parallel with the inspection process. This, in turn, maximizes system throughput. Although a 180° rotation is described herein, other degrees of rotation may also be used.

[0036] exist Figure 2 and Figure 3 In the exemplary embodiment shown, the support structure is a rotary indexing stage or rotary platform supporting four wafer / package chucks. However, several variations and modifications are possible. For example, the ultrasonic scanner may have two, three, four, or more wafer chucks. While the exemplary scan axis pusher assembly has two pushers, a single pusher or multiple pushers may be used. Additionally, the transducer mount may be able to hold one, two, or more transducers to minimize scan time. In some embodiments, the support structure can accommodate any number of wafer / package chucks, and similarly, any number of pushers and transducer mounts can be used for any number of wafer / package chucks.

[0037] Height-adjustable four-wafer chuck in a single rotary stage Figure 4 A scanner for an ultrasonic inspection system according to various representative embodiments is shown. Figure 4 In the exemplary embodiment shown, scanner 400 is constructed around scan slot 402, and rotating support structure 404 is located within scan slot. In this exemplary embodiment, support structure 404 is an indexing stage or a rotary stage. Wafer chuck 406 is positioned for loading and unloading wafers, while wafer chuck 408 is positioned in the scanning station ready for inspection using transducer 410. In operation, sample wafers or packages are automatically placed onto wafer chuck 406 by a robotic handler or manually by an operator. Once a wafer or package is loaded onto wafer chuck 406, the system rotates support structure 404 180° to position the sample in the scanning station ready for inspection. The scanning process begins to inspect the sample on wafer chuck 406. Simultaneously, wafer chuck 408 loads a new sample. Once the inspection of the sample on wafer chuck 406 is complete, the rotary stage support rotates back to its original position to allow unloading of the sample. While unloading an inspected sample from wafer chuck 406 and loading a new sample, the scanner can simultaneously begin inspecting a sample from wafer chuck 408. This minimizes downtime between scans and maximizes system throughput by preparing the next sample in parallel with the inspection process. Although this paper describes a 180° rotation, other degrees of rotation may also be used.

[0038] Figure 5 A wafer chuck assembly 500 with height-adjustable wafer chucks is illustrated according to various representative embodiments. In the illustrated embodiment, the wafer chuck assembly 500 includes four wafer chucks coupled to a rotary indexing stage support structure 404. Each wafer chuck is configured to be raised and lowered using one or more retainer lifters. The retainer lifters may be, for example, electromechanical or pneumatic actuators coupled between a retainer and the support structure. Wafer chuck 406 is depicted in a raised position, as indicated by arrow 502, while wafer chuck 408 is depicted in a lowered position, as indicated by arrow 504. This height adjustment enables the inspection system to perform ultrasonic scanning underwater, with wafer chuck 408 and its corresponding wafer immersed in a scanning tank. Prior to scanning, the mounting surfaces of the wafer chucks outside the scanning station are raised above the water level, allowing a robot or technician to place sample wafers or packages into the wafer chucks. The wafer chuck is then immersed underwater, and the support structure 404 is rotated to allow scanning of sample wafers or packages.

[0039] According to one embodiment, the height-adjustable wafer chuck may utilize two or more retainer lifters. The retainer lifters can be independently actuated to adjust the tilt of the wafer about one or two axes. For example, the tilt can be adjusted to align the wafer parallel to the scanning plane.

[0040] Optionally, the flexible bellows 506 can be used to enclose and protect the height adjustment mechanism of the wafer chuck. Height adjustment can be achieved, for example, by electromechanical, mechanical, or pneumatic means or a combination thereof.

[0041] exist Figure 4 and Figure 5 In the exemplary embodiment shown, the support structure 404 is a rotary indexing stage supporting four wafer / package chucks. However, as described above, several variations and modifications are possible. For example, the ultrasonic scanner may have two, three, four, or more wafer chucks. While the exemplary scan axis pusher assembly has two pushers, a single pusher or more than two pushers may be used in other embodiments. Additionally, the transducer mount may be able to hold one, two, or more transducers. In some embodiments, the support structure may accommodate any number of wafer / package chucks, and similarly, any number of pushers and transducer mounts may be used for any number of wafer / package chucks.

[0042] Height-adjustable wafer chucks enable ultrasonic inspection systems to perform ultrasonic scanning of wafers underwater by raising and lowering the wafer chucks. This eliminates the need for water couplers during the scanning process, as the entire scanning process can be performed underwater. Consequently, fewer water pipes are required and less water is needed for the scanning.

[0043] Four wafer chucks in a dual-rotation stage Figure 6 and Figure 7 A scanner 600 of an inspection system according to various representative embodiments is shown. Reference Figure 6 The scanner is constructed around a scanning slot 602. Two rotating support structures 604 are located adjacent to each other within the scanning slot. With the support structures 604 oriented as shown, a wafer chuck 606 is positioned for loading and unloading, while a wafer chuck 608 is positioned in the scanning station for scanning through a transducer 610. The rotating support structures 604 are configured to rotate about a rotating spindle 612.

[0044] Figure 7This is a top view of the scanner 600 according to various representative embodiments. Sample wafers or packages are automatically placed onto wafer chuck 606 using an atmospheric robot, or manually by an operator. Once the wafer or package is loaded onto wafer chuck 606, the system rotates two support structures 604 180°, as indicated by arrow 702, to position the sample for inspection using a motorized rotating mandrel 612 or equivalent mechanism. The scanning process then begins to inspect the sample on wafer chuck 606. Simultaneously, a new sample is loaded onto wafer chuck 608. Once the inspection of the sample on wafer chuck 606 is complete, the two support structures 604 rotate 180° back to their original positions to unload the sample. The scanner can begin inspecting the sample on wafer chuck 608 simultaneously while unloading the inspected sample from wafer chuck 606 and loading a new sample into wafer chuck 606. This minimizes downtime between scans and maximizes system throughput by preparing subsequent samples in parallel with the inspection process. Although this article describes a 180° rotation (corresponding to object holders placed diametrically opposite each other on a rotating support), other degrees of rotation may also be used. For example, the angle between the object holders may be less than or greater than 180°.

[0045] Figure 6 and Figure 7 The exemplary embodiment shown has a dual rotatable support structure that supports four wafer / package chucks together. However, several variations and modifications are possible. For example, the scanner may use fewer or more wafer chucks, and the scan axis pusher assembly may have two pushers, a single pusher, or multiple pushers. Additionally, the transducer mounts may each be capable of holding one, two, or more transducers. Using fewer wafer chucks on the support structure allows for better stability and wafer chuck alignment because the separate rotation mechanism enables very precise control of the wafer chucks. Additionally, manufacturing costs can be reduced. In some embodiments, the support structure can accommodate any number of wafer / package chucks, and similarly, any number of pushers and transducer mounts can be used for any number of wafer / package chucks.

[0046] Height-adjustable four-wafer chuck in a dual-rotation stage Figure 8 A wafer chuck assembly 800 with height-adjustable wafer chucks according to various representative embodiments is shown. The wafer chuck assembly 800 includes a first rotatable support structure 802 supporting height-adjustable wafer chucks 804 and 806, and a second rotatable support structure 808 supporting height-adjustable wafer chucks 810 and 812. (Refer to above) Figure 5The upper mounting surface of the wafer chuck can be raised above the water in the scanning tank to allow for loading and unloading of wafers or packages, and can be lowered below the water surface in the scanning tank for ultrasonic inspection. Sample wafers or packages are automatically placed on wafer chucks 804 and 810 using an atmospheric robot, or manually by an operator. Once the wafer or package is loaded onto wafer chucks 804 and 810, the system rotates the two support structures 180° to position the sample for inspection. The scanning process begins to inspect the samples on wafer chucks 804 and 810. Simultaneously, wafer chucks 806 and 812 are loaded with new samples. Once the inspection of the samples on wafer chucks 804 and 810 is complete, the two support structures rotate 180° back to their original positions to allow the samples to be unloaded. While unloading inspected samples from wafer chucks 804 and 810 and loading new samples into wafer chucks 804 and 810, the scanner can simultaneously begin inspecting samples on wafer chucks 806 and 812. This minimizes downtime between scans and maximizes system throughput by preparing subsequent samples in parallel with the inspection process. A flexible bellows 814 can be used to cover and protect the lifter mechanism of the object holder.

[0047] exist Figure 6-8 In the illustrated embodiment, the two support structures are configured to reduce the required size of the scan slot. Specifically, the motorized rotating mandrel is positioned such that wafer chucks 806 and 812 in the scanning station are positioned further apart than wafer chucks 804 and 810, which are positioned for loading and unloading. Parallel support structures would require pivot points further apart to maintain the same transducer spacing, thus requiring a wider slot. In this configuration, there is insufficient space for the two support structures to rotate together. Movements such as those via rotation of support structures 802 and 808 can be performed sequentially to provide sufficient clearance between the support structures. For example, rotation of one support structure can begin before rotation of the other support structure to provide sufficient clearance between the first and second support structures during rotation.

[0048] Figure 9 This is a flowchart of an ultrasound examination method 900 according to various representative embodiments. Figure 9 The operation of one or more support structures is described, each support structure supporting two or more wafer chucks. As mentioned above, the support structure can support more than two wafer chucks, and one or more support structures can be used in a scanner. When two or more support structures are used, they can each operate synchronously or sequentially according to process 900. Reference Figure 9At block 902, the wafer to be inspected is picked up from a carrier such as a front-opening wafer transfer cassette (FOUP), pre-aligned with the scanner's wafer chuck A, and placed onto wafer chuck A. At block 904, the support structure supporting wafer chuck A and wafer chuck B is rotated to position wafer chuck A in the scanner's scanning station and to position wafer chuck B for loading and unloading. At block 906, the wafer in wafer chuck A is inspected. At block 908, while wafer A is being inspected, another wafer (if present) is unloaded from wafer chuck B and moved to the dryer. At block 910, the next wafer is picked up from the FOUP, pre-aligned, and placed on wafer chuck B. At block 912, the support structure is rotated again to position wafer chuck B in the scanner's scanning station and to position wafer chuck A for loading and unloading. At block 914, the wafer in wafer chuck B is inspected. At block 916, during wafer inspection, the wafer is unloaded from wafer chuck A and moved to the dryer. At block 918, the next wafer is picked up from the FOUP, pre-aligned, and placed on wafer chuck A. The process returns to block 904 and repeats until no more wafers are to be scanned and the scanned wafers have been unloaded.

[0049] Block 906 is executed in parallel with blocks 908 and 910. Blocks 916 and 918 are executed in parallel with block 914.

[0050] In some embodiments, method 900 may utilize multiple support structures simultaneously. In such embodiments, each block of method 900 may occur simultaneously using one support structure and a corresponding block using another support structure. For example, at block 906, a first wafer in wafer chuck A of the first support structure is inspected, and simultaneously, a second wafer in wafer chuck A of the second support structure is inspected. Similarly, at block 908, a third wafer is unloaded from wafer chuck B of the first support structure and moved to the dryer, while a fourth wafer is unloaded from wafer chuck B of the second support structure. Thus, each block of method 900 may occur using more than one support structure. Furthermore, the support structures are configured to ensure rotation such that each support structure does not obstruct the others.

[0051] When wafers are automatically loaded and unloaded via robotic handlers, the same handlers can be used to retrieve wafers from the dryer and return them to FOUP or transfer them to another process.

[0052] Wafer processing As described above, an object holder can be, for example, a wafer chuck. A wafer chuck is a mechanical, electromechanical, or pneumatic mechanism, or a combination thereof, used to securely hold a semiconductor wafer in place during wafer handling. The wafer chuck is an essential part of any semiconductor machine because it directly handles the wafer for various manufacturing processes.

[0053] Generally speaking, wafers can be divided into "fractalless wafers" and "fractal wafers". Figure 10 The first category is described, in which wafer 1002 does not contain any grains on the wafer surface, and typically these types of wafers are smooth on both sides. Figure 11 A second category is depicted, in which wafer 1104 has semiconductor grains 1102 attached to the wafer surface. Typically, these wafers have multiple grains attached to one side of the surface, which makes the wafer surface uneven depending on the thickness of the grains.

[0054] These two types of wafers can be processed, scanned, or inspected in the same system during manufacturing. Typically, different types of wafers (“dieless wafers” and “die-bearing wafers”) use different wafer chucks to hold them. In this case, the wafer chucks must be manually changed every time the semiconductor machine switches from one type of wafer to another. These manual wafer chuck changes result in more downtime and lower productivity. Any reduction in system downtime can lead to increased productivity.

[0055] Die-bearing wafers need to be picked up using the surface of the wafer where no dies are present to prevent damage to the dies. Depending on the application, this can be the top or bottom surface. Die-free wafers are typically picked up using the bottom surface of the wafer, but in some applications, they can be handled using the top surface. Therefore, it is advantageous for wafer chucks to work with different types of wafer handlers.

[0056] Embodiments of this disclosure provide a wafer chuck configured to hold two types of wafers (i.e., "dieless wafers" and "die-bearing wafers") in a single-wafer chuck design. This significantly improves throughput by avoiding wafer chuck replacements when wafer types change. Wafers are held only at wafer edges, and a lifter mechanism lifts the wafers above the wafer chuck whenever they need to be picked up and loaded from it.

[0057] Figure 10 The image shows a wafer 1002 before semiconductor dies are manufactured. A dieless wafer 1002 is typically picked up using the bottom surface of the wafer.

[0058] Figure 11 A wafer 1100 with fabricated dies 1102 is shown. The wafer 1100 can be touched and picked up using the die-free surface of the wafer (the top surface in the figure). The wafer 1100 also has a die "forbidden zone" 1104 at the bottom edge of the wafer. If desired, it is permissible to touch and hold the bottom surface of the wafer only within the forbidden zone.

[0059] Figure 12AA wafer chuck 1200 with a wafer lifter mechanism 1202 is shown according to various representative embodiments. The wafer lifter mechanism has pins 1204 for raising and lowering the wafer. Pins 1204 can be raised above an outer ring 1206 of the wafer chuck body, as shown in the figure. For example, the wafer lifter mechanism can be actuated mechanically, pneumatically, or electromechanically. The wafer chuck 1200 includes an inner ring 1208 that supports an internal region of the wafer.

[0060] Figure 12B Another wafer chuck 1220 with a wafer lifter mechanism 1202 is shown according to various representative embodiments. The wafer chuck 1220 has an outer ring 1206 that supports the outer edge of the wafer, but no inner ring to ensure that it does not contact the dies on the wafer.

[0061] To enable wafer handling from below, existing wafer handlers have a recessed ring to allow removal of the handler after the wafer has been placed on the wafer chuck. As disclosed herein, using a wafer lifter allows the use of a full outer ring without the recess that accommodates the handler. In one embodiment, the wafer chuck has a full outer ring configured to support an outer region on the underside of the wafer. Having a full outer ring allows for greater control over the inspection process, to optionally immerse the wafer surface or optionally protect the wafer edges to minimize water ingress. This will depend on the application. This control is not possible with recessed wafer handlers and is therefore an advantage of wafer lifters.

[0062] Figure 13 A side view of a wafer chuck 1200 or wafer chuck 1220 according to various representative embodiments is shown. In this view, three pins 1204 of the wafer lifter mechanism are raised to support the wafer 1302.

[0063] Figure 14A This is another view of a wafer chuck 1200 with a wafer lifter mechanism 1202 according to various representative embodiments. In this view, the pin 1204 is lowered to a position at or below the upper surface of the outer ring 1206. The wafer chuck 1200 includes an inner ring 1208 that supports an internal region of the wafer.

[0064] Figure 14B A corresponding view of a wafer chuck 1220 without any inner rings is shown.

[0065] Figure 15 A side view of a wafer chuck 1200 or 1220 according to various representative embodiments is shown. In this view, three pins 1204 are lowered, thereby allowing the wafer 1302 to be supported by the upper surface of the outer ring 1206.

[0066] Figure 16The illustration depicts the working principle of handling "dieless wafers" according to various representative embodiments. The same working principle can be used for applications where the die is fabricated on the top side of the wafer. In some embodiments, an end effector 1602 located at the end of a robotic arm is used to hold the wafer 1302 and transport it from one station to another. The end effector 1602 is a gripping tool for automatically handling the wafer. Figure 16 As depicted in configuration (A), for a dieless wafer, end effector 1602 uses the bottom surface of the wafer to hold wafer 1302 and pre-aligns the wafer with the outer ring 1206 of the wafer chuck, as shown by arrow 1604. In configuration (B), the end effector is lowered, as shown by arrow 1606. This places wafer 1302 on pin 1204 of the wafer lifter mechanism. In configuration (C), the end effector 1602 is further lowered. At this position, the end effector is positioned between wafer 1302 and the upper surface of the wafer chuck. Thus, the wafer lifter mechanism is able to create a space 1608 between the wafer and the wafer chuck sufficient to allow the end effector to pass between and retract between the wafer and the wafer chuck, as depicted in configuration (D). Once the wafer is placed on the wafer lifter mechanism, the mechanism is lowered to place the wafer on the outer ring of the wafer chuck, as depicted in configuration (E). Then, the wafer is rigidly attached to the wafer chuck using a vacuum or any other similar means.

[0067] Working principle of handling "grained wafers" Please refer to the above text. Figure 16 The process involves handling wafers with dies on the top side. Alternatively, when the dies are on the bottom side of the wafer, the end effector holds the wafer using the top surface of the wafer (using a vacuum or edge clamp) and places the wafer at the outer ring of the wafer chuck, with the wafer lifter in a lowered position. Note that the bottom surface of the wafer has dies, and contact with the die surface is not permitted during wafer handling. In this case, the end effector will be positioned above the top surface of the wafer. Once the wafer is placed on the outer ring of the wafer chuck, it is rigidly attached to the wafer chuck using a vacuum or any other similar means. Here, only the wafer's stop zone contacts the outer ring of the wafer chuck.

[0068] Figure 17This is a flowchart of a method 1700 for operating a wafer chuck with a wafer lifter according to various representative embodiments. This method can be used for dieless wafers or wafers with dies on their top surface. At block 1702, the wafer lifter is lifted. At block 1704, the dieless wafer is picked up from a FOUP or other holder using a robotic end effector and pre-aligned with the wafer chuck. The wafer is supported on its underside. At block 1706, the end effector is lowered to place the wafer on the wafer lifter. At block 1708, the end effector is lowered away from the wafer and retracted at block 1710. At block 1712, the wafer lifter is lowered to place the wafer on the wafer chuck, and a vacuum is applied to hold the wafer on the wafer chuck. In this way, the same wafer chuck can be used to hold both dieless and diesless wafers. This further saves time previously used when changing wafer chucks.

[0069] The wafer chuck assembly may include both a retainer lifter and a wafer lifter, the retainer lifter being actuated to raise the object retainer above the water level in the scanning tank and to lower it, and the wafer lifter being used to support the wafer above the wafer chuck to allow the underside of the wafer to be touched during handling.

[0070] In this document, relational terms such as first and second, top and bottom may be used individually to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between these entities or actions. The terms “comprising,” “including,” “containing,” “having,” “possessing,” “having,” or any other variation thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but may also include other elements not expressly listed or inherent to such a process, method, article, or apparatus. Without further limitation, an element beginning with “comprising” does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0071] Throughout this document, references to "an embodiment," "some embodiments," "embodiment," "implementation," "aspect," or similar terms mean that a particular feature, structure, or characteristic described in combination with that embodiment is included in at least one embodiment of this disclosure. Therefore, the appearance of such terms or throughout this specification does not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics may be combined in any suitable manner without limitation.

[0072] As used herein, the term "or" should be interpreted as including or referring to any one or any combination thereof. Therefore, "A, B, or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C." Exceptions to this definition will only occur if the combination of elements, functions, steps, or actions is inherently mutually exclusive in some way.

[0073] As used herein, the term “constructed” when applied to an element means that the element can be designed or constructed to perform a specified function, or that it has the necessary structure that enables it to be reconstructed or adapted to perform that function.

[0074] Numerous details have been set forth to provide an understanding of the embodiments described herein. These embodiments may be practiced without these details. In other instances, well-known methods, procedures, and components have not been described in detail to avoid obscuring the described embodiments. This disclosure should not be construed as limiting the scope of the embodiments described herein.

[0075] Those skilled in the art will recognize that this disclosure has been described by way of example. This disclosure can be implemented using hardware component equivalents, such as dedicated hardware and / or dedicated processors, which are equivalent to the described and claimed disclosure. Similarly, dedicated processors and / or dedicated hardwired logic can be used to construct alternative equivalent embodiments of this disclosure.

[0076] The various embodiments described herein are implemented using dedicated hardware, configurable hardware, or a programmable processor that executes programming instructions, which are broadly described in flowchart form and can be stored on any suitable electronic storage medium or transmitted via any suitable electronic communication medium. Combinations of these elements may be used. Those skilled in the art will appreciate that the processes and mechanisms described above can be implemented with any number of variations without departing from this disclosure. For example, the order of certain operations performed can often be changed, additional operations can be added, or operations can be deleted without departing from this disclosure. Such variations are contemplated and considered equivalent.

[0077] The various representative embodiments described in detail herein are presented as examples rather than as limitations. Those skilled in the art will understand that various changes in form and detail may be made to the described embodiments to produce equivalent embodiments that still fall within the scope of the appended claims.

Claims

1. An ultrasonic inspection system, comprising: One or more ultrasound scanning stations; One or more support structures, each of which is movable between a first orientation and a second orientation; A plurality of object holders coupled to a support structure in one or more support structures, and including at least first and second object holders, each object holder configured to hold an object for ultrasonic scanning, wherein: In the first orientation of the support structure, the first object retainer is positioned to allow loading or unloading of the first object retainer, and the second object retainer is positioned in one or more ultrasonic scanning stations. as well as In the second orientation of the support structure, the second object retainer is positioned to allow loading or unloading of the second object retainer, and the first object retainer is positioned in one or more of the ultrasonic scanning stations.

2. The ultrasonic inspection system according to claim 1, wherein, At least one of the plurality of object holders is a wafer chuck configured to hold a semiconductor wafer for ultrasonic scanning.

3. The ultrasonic inspection system according to claim 1, wherein, The support structure in one or more of the support structures is coupled to a plurality of object retainers.

4. The ultrasonic inspection system according to claim 1, wherein, The one or more ultrasonic scanning stations include two ultrasonic scanning stations, and the one or more supporting structures include two supporting structures.

5. The ultrasonic inspection system according to claim 1, wherein, The ultrasonic scanning station in the one or more ultrasonic scanning stations includes an ultrasonic transducer and a water coupler.

6. The ultrasonic inspection system of claim 1 further includes a scanning slot, wherein an object holder positioned in the ultrasonic scanning station is configured to hold an object in the scanning slot.

7. The ultrasonic inspection system according to claim 6, wherein, The object holder is coupled to the support structure via one or more holder lifters configured to move the object holder between a first position and a second position, the first position being above the water level in the scanning tank for loading and unloading, and the second position being below the water level in the scanning tank for ultrasonic scanning.

8. The ultrasonic inspection system according to claim 6, wherein, The object retainer is coupled to the support structure via two or more retainer lifters configured to adjust the tilt of the object retainer in the ultrasonic scanning station of the one or more scanning stations.

9. The ultrasonic inspection system according to claim 1, wherein, The object holders among the plurality of object holders are wafer chucks, and the ultrasonic inspection system also includes a plurality of wafer lifters located in the peripheral region of the wafer chuck and configured as follows: The semiconductor wafer is supported at a first position above the wafer chuck, the first position allowing the robotic positioning arm to pass between the wafer chuck and the underside of the semiconductor wafer; as well as Move to a second position below the first position so that the semiconductor wafer can be supported by the wafer chuck on its underside.

10. The ultrasonic inspection system according to claim 9, wherein, A wafer chuck has a complete outer ring that is configured to support the outer region of the wafer.

11. The ultrasonic inspection system according to claim 1, wherein, The support structure includes a rotatable indexing table.

12. A method for ultrasonic scanning, comprising scanning multiple objects in an ultrasonic inspection system: The support structure is moved to a first orientation, wherein a first object holder coupled to the support structure is located outside the ultrasonic scanning station of the ultrasonic inspection system, and a second object holder coupled to the support structure is located inside the ultrasonic scanning station. Perform an ultrasonic scan of the object in the second object holder; Unload the previously scanned object from the first object holder; Load one of the plurality of objects to be scanned onto the first object holder; The support structure is moved to a second orientation, wherein the first object holder is located in the ultrasonic scanning station and the second object holder is located outside the ultrasonic scanning station; Perform an ultrasonic scan of the object in the first object holder; Unload the previously scanned object from the second object holder; as well as The object to be scanned is loaded onto the second object holder.

13. The method according to claim 12, wherein, The movement includes rotation, and wherein the support structure is a first support structure of an ultrasonic inspection system having a first support structure, a second support structure, and two ultrasonic scanning stations, the method further includes: The first support structure is rotated before the second support structure rotates, so as to provide sufficient clearance between the first support structure and the second support structure during rotation.

14. The method according to claim 12, wherein, The supporting structure is the first supporting structure of an ultrasonic inspection system having a first supporting structure, a second supporting structure, and two ultrasonic scanning stations. The method further includes: The second support structure is moved to the first orientation, wherein a third object holder coupled to the second support structure is located outside the ultrasonic scanning station of the ultrasonic inspection system, and a fourth object holder coupled to the second support structure is located in the ultrasonic scanning station. Perform an ultrasonic scan of the object in the fourth object holder; Unload the previously scanned object from the third object holder; The objects from the plurality of objects to be scanned are loaded onto the third object holder; The second support structure is moved to a second orientation, wherein the third object holder is located in the ultrasonic scanning station and the fourth object holder is located outside the ultrasonic scanning station. Perform an ultrasonic scan of the object in the third object holder; Unload the previously scanned object from the fourth object holder; and The object to be scanned is loaded onto the fourth object holder.

15. The method of claim 12, further comprising: Raise the first object holder out of the water tank to unload the previously scanned object from the first object holder; The first object holder is lowered into the water tank in order to scan the object in the first object holder; Raise the second object holder out of the tank to unload the previously scanned object from the second object holder; as well as The second object holder is lowered into the water tank to scan the object in the second object holder.

16. The method according to claim 12, wherein, Raising or lowering the first object retainer includes actuating one or more retainer lifters coupled between the first object retainer and the support structure.

17. The method according to claim 12, wherein, Raising or lowering the first object retainer includes a plurality of retainer lifters actuated and coupled between the first object retainer and the support structure and located in the peripheral region of the first object retainer.

18. The method of claim 17, further comprising: The orientation of the first object retainer is adjusted using the plurality of retainer lifters.

19. The method according to claim 12, wherein, The first object holder is a wafer chuck, and the method further includes: Raise multiple wafer lifters located in the peripheral area of ​​the wafer chuck; The semiconductor wafer is placed on the plurality of wafer lifters using a robotic positioning arm positioned between the lower surface of the semiconductor wafer and the upper surface of the wafer chuck. Retract the robotic positioning arm; and The plurality of wafer lifters are lowered to place the lower side of the semiconductor wafer on the upper surface of the wafer chuck.

20. The method of claim 12, wherein: In the first orientation, a third object holder coupled to the support structure is located outside the second ultrasonic scanning station of the ultrasonic inspection system, and a fourth object holder coupled to the support structure is located in the second ultrasonic scanning station; as well as In the second orientation, the third object holder is located in the second ultrasonic scanning station, and the fourth object holder is located outside the second ultrasonic scanning station.

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