Multi-hold inspection system using a movable support structure

Abstract

The ultrasonic flaw detection system includes an ultrasonic scanning area, a support structure, and two or more object holders coupled to the support structure. The support structure is movable between first and second configurations. The object holders can hold objects to be ultrasonically scanned. In the first configuration of the support structure, the first object holder is positioned in the ultrasonic scanning area, and the second object holder is positioned in a loadable and unloadable location. In the second configuration, the second object holder is positioned in the ultrasonic scanning area, and the first object holder is positioned in a loadable and unloadable location. The object holders can be raised above the water surface for loading and unloading, and lowered below the water surface for ultrasonic flaw detection. The object holders may have wafer risers for holding semiconductor wafers above the object holders for automated handling.

Description

Technical Field

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 456,706, filed on April 3, 2023, with the title "Multi-Chuck Inspection System", and also claims the benefit of U.S. Patent Application No. 18 / 624,537, filed on April 2, 2024, with the title "Multi-Holder Inspection System Using a Movable Support Structure", the entire contents of which are incorporated herein by reference.

Background Art

[0002] Ultrasonic flaw detection inspection devices are used to perform non-destructive testing (NDT) on semiconductor wafers and packages to detect potential quality issues and manufacturing defects. Semiconductor manufacturers are constantly trying to shorten inspection times to improve productivity during the production stage. Therefore, it is necessary to shorten inspection times to improve productivity.

[0003] Currently available ultrasonic flaw detection inspection devices have one or more fixed wafer chucks and one long scan axis motor assembly or two independent assemblies for performing scans. Each wafer chuck may be equipped with one or more ultrasonic transducers to shorten the overall scan time. In these systems, throughput is improved by scanning multiple wafers in parallel.

Prior Art Documents

Patent Documents

[0004] <00​​​​​​​​​​​​​​​​​"Glossary of Semiconductor Manufacturing Equipment Terms (Factory Integration)," Japan Semiconductor Manufacturing Equipment Association, includes an explanation of "FOUP" [online], [Accessed November 26, 2025], Internet<https: / / www.seaj.or.jp / semi / yogo / factory / words.html> [Non-Patent Document 2] "Vol. 20 Load Port for 300mm Wafers: Advanced FA Technology Evaluated by the Semiconductor Industry," TDK Corporation, Tech Encyclopedia, [online], [Accessed November 26, 2025], Internet<https: / / www.tdk.com / ja / tech-mag / illustrated / 020> [Overview of the project] [Problems that the invention aims to solve]

[0006] However, throughput is still limited by the switchover time between scans. The currently available equipment has a significant delay before the next scan can begin, as it requires removing the previous wafer from the wafer chuck and placing a new wafer into the chuck. [Means for solving the problem]

[0007] The various apparatuses and devices described herein relate to test and measurement systems, and in particular to inspection systems and inspection methods such as ultrasonic testing systems for devices under test (DUTs).

[0008] Current systems for ultrasonic testing of semiconductor wafers have a significant delay because, before the next scan begins, the preceding wafer is removed from the wafer chuck that holds the wafer to be inspected while a new wafer is placed in the wafer chuck. The various systems disclosed herein improve throughput by minimizing scan time in addition to minimizing the switching time between scans.

[0009] Embodiments of this disclosure include a multi-chuck platform capable of handling three or more wafer chucks, and an integrated support structure (such as an index table or carousel) for seamless handling and scanning of wafers / packages. This significantly improves throughput by loading, aligning, and queuing the next wafer or package while the previous inspection is still in progress.

[0010] Various embodiments provide an ultrasonic flaw detection system which includes one or more ultrasonic scanning stations, one or more support structures, and a plurality of object holders coupled to the support structures. The support structures may be movable, for example, a rotatable indexing table. Each object holder is configured to hold an object to be ultrasonically scanned. Each support structure is movable and may be rotatable between a first and a second configuration. In the first configuration of the support structure, the first object holder is positioned so as to allow loading and unloading of the first object holder, and the second object holder is positioned within one of the ultrasonic scanning stations. In the second configuration of the support structure, the second object holder is positioned so as to allow loading and unloading of the second object holder, and the first object holder is positioned within the ultrasonic scanning station. The object holders may be wafer chucks configured to hold semiconductor wafers to be ultrasonically scanned.

[0011] The ultrasonic scanning area contains an ultrasonic transducer. In one example, the ultrasound from the transducer is coupled to the object using a water coupler. In another example, the ultrasonic flaw detection system has a scan tank containing water. In this embodiment, the ultrasound is coupled to the object by immersing the transducer and the object in the water tank. In some embodiments, other scanning devices or other scanning techniques may be used in the scanning area (scanning station).

[0012] In some embodiments, the object may be held in a scan tank for ultrasonic testing. The object holder may be coupled to a support structure by a mechanism for moving it between a first position above the water level in the scan tank (for loading and unloading) and a second position submerged in the water in the scan tank (for ultrasonic scanning). The object holder is coupled to the support structure by three actuators configured to adjust the position of the object holder within the ultrasonic scanning area.

[0013] The wafer chuck of an ultrasonic flaw detection system may have wafer risers positioned in the area surrounding the wafer chuck. The wafer risers can rise to support the semiconductor wafer in a first position above the wafer chuck, allowing a robot positioning arm to pass between the wafer chuck and the underside of the semiconductor wafer. The wafer risers can then descend to a second position below the first position, allowing the semiconductor wafer to be supported at its underside by the wafer chuck.

[0014] Various embodiments provide methods for operating an ultrasonic flaw detection system, which include moving (i.e., rotating) a support structure to a first position so that a first object holder coupled to the support structure is outside the ultrasonic scanning area of ​​the ultrasonic flaw detection system and a second object holder coupled to the support structure is inside the ultrasonic scanning area, ultrasonically scanning objects in the second object holder, unloading (removing) previously scanned objects from the first object holder, loading (mounting) one of several objects to be scanned into the first object holder, moving (i.e., rotating) the support structure to a second position so that the first object holder is inside the ultrasonic scanning area and the second object holder is outside the ultrasonic scanning area, ultrasonically scanning objects in the first object holder, unloading previously scanned objects from the second object holder, and loading objects to be scanned into the second object holder.

[0015] In one embodiment, the first object holder is raised from the water tank to unload objects that have already been scanned, the first object holder is lowered into the water tank to scan the objects in the first object holder, the second object holder is raised from the water tank to unload objects that have already been scanned, the second object holder is lowered into the water tank to scan the objects in the second object holder. In one embodiment, the object holders rise and fall when positioned to perform loading and unloading. However, generally, the object holders may be able to rise or fall in any arrangement of the support structure.

[0016] One embodiment includes raising wafer risers positioned in the peripheral area of ​​the wafer chuck, using a robotic positioning arm positioned between the lower surface of the semiconductor wafer and the upper surface of the wafer chuck to position the semiconductor wafer on multiple risers, withdrawing the robotic positioning arm, and lowering the wafer risers to position the lower surface of the semiconductor wafer on the upper surface of the wafer chuck. [Brief explanation of the drawing]

[0017] [Figure 1] Figure 1 shows an ultrasonic flaw detection inspection system according to various representative embodiments. [Figure 2] Figure 2 shows an example of a scanner of an inspection system according to various representative embodiments. [Figure 3] Figure 3 shows an example of a scanner of an inspection system according to various representative embodiments. [Figure 4] Figure 4 shows a scanner of an ultrasonic flaw detection inspection system according to various representative embodiments. [Figure 5] Figure 5 shows a wafer chuck assembly having a height-adjustable wafer chuck according to various representative embodiments. [Figure 6] Figure 6 shows a scanner of an inspection system according to various representative embodiments. [Figure 7] Figure 7 shows a scanner of an inspection system according to various representative embodiments. [Figure 8] Figure 8 shows a wafer chuck assembly having a height-adjustable wafer chuck according to various representative embodiments. [Figure 9] Figure 9 is a flowchart of an ultrasonic flaw detection inspection method according to various representative embodiments. [Figure 10] Figure 10 shows a wafer without a die attached. [Figure 11] Figure 11 shows a wafer with a die attached. [Figure 12A] Figure 12A shows a wafer chuck having a wafer lifter mechanism according to various representative embodiments. [Figure 12B] Figure 12B shows a wafer chuck having a wafer lifter mechanism according to various representative embodiments. [Figure 13] Figure 13 shows a side view of a wafer chuck having a wafer lifter mechanism according to various representative embodiments. [Figure 14A]Figure 14A is a further diagram of a wafer chuck having a wafer riser mechanism, based on various representative embodiments. [Figure 14B] Figure 14B is a further diagram of a wafer chuck having a wafer riser mechanism according to various representative embodiments. [Figure 15] Figure 15 shows side views of wafer chucks having wafer riser mechanisms according to various representative embodiments. [Figure 16] Figure 16 shows the wafer handling principles according to various representative embodiments. [Figure 17] Figure 17 is a flowchart illustrating the operation method of a wafer chuck using a wafer riser according to various representative embodiments. [Modes for carrying out the invention]

[0018] While the disclosed technology can be implemented in a wide variety of forms, the embodiments illustrated and described herein are intended to provide examples of the principles of the disclosed technology. Therefore, detailed specific embodiments are illustrated and described herein, but the disclosed technology is not intended to be limited to these specific embodiments. In the following description, similar reference numerals are used to describe identical, similar, or corresponding parts in some of the drawings. For the sake of simplification and clarity, reference numerals may be repeated between drawings to indicate corresponding or similar elements.

[0019] The accompanying drawings provide visual representations and are used to further illustrate various representative embodiments, and will be useful for those skilled in the art to better understand the representative embodiments disclosed and their essential advantages. In these drawings, corresponding or similar elements are identified by similar reference numerals.

[0020] Figure 1 shows an ultrasonic flaw detection system 100 in various representative embodiments. The scanner 102, located within the housing 104, is the core process module of the system and performs wafer / package inspection. The housing 104 also contains a robotic module 106 for wafer handling, electrical, plumbing, and computer control panels 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 waiting time between scans by integrating a rotatable chuck support structure, such as an index table or carousel, within the scanner's scan tank.

[0021] The following disclosures relate to semiconductor wafer chucks. Wafer chucks are typically used to support semiconductor wafers during the inspection process. The wafer may be held in the wafer chuck by creating a vacuum between the wafer and the surface of the wafer chuck. However, it should be noted that in some embodiments, other types of object holders may be used instead of wafer chucks. An object holder may be any holding mechanism for supporting wafers, trays, packages, or other objects or devices under test. This method is not limited to semiconductor wafers or packages and can be used for any type of sample.

[0022] Furthermore, the techniques disclosed herein will be described below with reference to movable or rotating index tables and carousels. However, various support structures may be used instead of rotating index tables. For example, each object holder may be supported by a rotatable arm, and two additional arms may be coupled to a central pivot to form a support structure.

[0023] An ultrasonic flaw detection system with four (quad) wafer chucks in a single carousel (rotating platform).

[0024] Figures 2 and 3 show examples of scanners 200 in inspection systems according to various representative embodiments. In the embodiment shown in Figure 2, the scanner 200 is built around a scan tank 202. The support structure 204 is a movable rotating index table (carousel) located within the scan tank. The support structure 204 is configured for four wafer chucks and their corresponding wafers. Two wafer chucks 206 are positioned to perform scans under ultrasonic transducers 208 in ultrasonic scanning stations, while two wafer chucks 210 are positioned to allow for wafer loading and unloading. The scanning stations are areas of the scanner 200 where objects are held for inspection. Figure 2 shows two scanning stations, each containing an ultrasonic transducer 208, a transducer mounting base 212 housing the ultrasonic transducer, and a forcer assembly 216. Multiple forcer assemblies 216 are mounted on a scan bridge 218 to move ultrasonic transducers in the scan axis direction 214 to scan wafers within the ultrasonic scan area. These forcer assemblies 216 may be capable of operating independently of one another. The scan area may further include a water coupler for supplying water to acoustically couple the ultrasonic waves generated by the transducers to the object under test.

[0025] Figure 3 shows a top view of the scanner 200 in various representative embodiments. A raster scan of a wafer in the wafer chuck 206 is performed by moving the transducer 208 in the direction of the scan axis 214 and the scan bridge 218 along the step axis side rail 304 in the direction of the step axis 302. The wafer chuck 210 is available for loading and unloading wafers. The support structure 204 is rotatable up to 180 degrees using an electric swivel spindle 306. Sample wafers and packages can be placed on the wafer chuck 210 automatically using an air transport 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 degrees to position the sample in the ultrasonic scanning area, ready for immediate inspection. The scanning process then begins to inspect the sample on the wafer chuck 210. Simultaneously, a new sample is loaded into wafer chuck 206, which has rotated and is currently outside the scanning area. Once inspection of the sample on wafer chuck 210 is complete, the support structure 204 rotates 180 degrees back to its original position, allowing the sample to be unloaded (removed). While the inspected sample on wafer chuck 210 is being unloaded and a new sample is being loaded into wafer chuck 210, 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 maximizes the system throughput. Although a 180-degree rotation is described herein, other rotation angles may also be used.

[0026] In the embodiment shown in Figures 2 and 3, the support structure is a swivel index table or carousel 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. In the example of the scan axis forser assembly, there are two forers, but one forser or multiple forers can be used. Furthermore, the transducer mount can accommodate 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 forers or transducer mounts can be used for any number of wafer / package chucks.

[0027] Four (quad) height-adjustable wafer chucks in a single carousel

[0028] Figure 4 shows scanners for ultrasonic flaw detection systems in various representative embodiments. In the embodiment of Figure 4, the scanner 400 is built around a scan tank 402, and the rotating support structure 404 is located inside the scan tank. In this embodiment, the support structure 404 is an index table or carousel. A wafer chuck 406 is positioned for loading and unloading wafers, while a wafer chuck 408 is positioned within the scan area to allow immediate inspection using the transducer 410. During operation, the sample wafer or package is automatically placed on the wafer chuck 406 by a robotic handler or manually by an operator. After the wafer or package is loaded onto the wafer chuck 406, the system rotates the support structure 404 180 degrees to position the sample in the scan area for immediate inspection. The scanning process begins inspecting the sample on the wafer chuck 406. Simultaneously, a new sample is loaded into the wafer chuck 408. Once the sample inspection on wafer chuck 406 is complete, the carousel support structure rotates back to its original position, allowing the sample to be unloaded. While the inspected sample on wafer chuck 406 is being unloaded and a new sample is being loaded, the scanner can simultaneously begin inspecting the sample on wafer chuck 408. By preparing the next sample in parallel with the inspection process, the downtime between scans is minimized, thereby maximizing system throughput. Although a 180-degree rotation is described here, other rotation angles may also be used.

[0029] Figure 5 shows a wafer chuck assembly 500 with height-adjustable wafer chucks in various representative embodiments. In the illustrated embodiments, the wafer chuck assembly 500 has four wafer chucks coupled to a swivel index table support structure 404. Each wafer chuck is configured to be raised and lowered using one or more holder risers. The holder risers may be, for example, electromechanical or pneumatic actuators that connect the holder to the support structure. Wafer chuck 406 is depicted in the raised position as indicated by arrow 502, while wafer chuck 408 is depicted in the lowered position as indicated by arrow 504. This height adjustment allows the inspection system to perform ultrasonic scanning underwater with wafer chuck 408 and the corresponding wafer immersed in a scan tank. Before scanning, the mounting surfaces of the wafer chuck outside the scanning area are elevated above the water level, allowing a robot or technician to place the sample wafer or package inside the wafer chuck. The wafer chuck is then submerged in water, and the support structure 404 is rotated to enable scanning of the sample wafer or package.

[0030] According to one embodiment, the height-adjustable wafer chuck may use two or more holder risers. These holder risers operate independently and can adjust the wafer tilt with respect to one or two axes. For example, the tilt may be adjusted to align the wafer parallel to the scanning plane.

[0031] Optionally, a flexible bellows 506 may be used to enclose and protect the wafer chuck height adjustment mechanism. Height adjustment may be achieved, for example, by electromechanical, mechanical, or pneumatic methods, or a combination thereof.

[0032] In the embodiments shown in Figures 4 and 5, the support structure 404 is a swivel index table 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. The illustrated scan axis forser assembly has two forsers, but in other embodiments, one or more forsers may be used. Furthermore, the transducer mounting base may accommodate one, two, or more transducers. In some embodiments, the support structure can accommodate any number of wafer / package chucks, and similarly, any number of forsers and transducer mounting bases can be used for any number of wafer / package chucks.

[0033] The height-adjustable wafer chuck allows the ultrasonic flaw detection system to perform ultrasonic scanning of wafers underwater by raising and lowering the wafer chuck. This enables the entire scanning process to be conducted underwater, eliminating the need for water couplers during the scanning process. As a result, the need for water channels and the amount of water required for scanning are reduced.

[0034] Four (quad) wafer chucks on two (dual) carousels

[0035] Figures 6 and 7 show scanner 600 of an inspection system according to various representative embodiments. Referring to Figure 6, the scanner is constructed around a scan tank 602. Two rotating support structures 604 are positioned adjacent to each other within the scan tank. With these support structures 604 arranged as shown, wafer chuck 606 is positioned for loading and unloading, while wafer chuck 608 is positioned within the scan area for scanning by transducer 610. The rotating support structures 604 are configured to rotate around a swivel spindle (rotation axis) 612.

[0036] Figure 7 shows a top view of the scanner 600 in various representative embodiments. Sample wafers or packages are placed on the wafer chuck 606 automatically using an air transport robot or manually by an operator. After the wafers or packages are loaded onto the wafer chuck 606, the system rotates both support structures 604 180 degrees, as indicated by arrow 702, to position the sample for immediate inspection using an electric swivel spindle 612 or equivalent mechanism. The scanning process is then initiated to inspect the sample on the wafer chuck 606. Simultaneously, the wafer chuck 608 loads a new sample. Once the inspection of the sample on the wafer chuck 606 is complete, both support structures 604 rotate 180 degrees back to their original positions to unload (remove) the sample. While the inspected sample on the wafer chuck 606 is being unloaded and a new sample is being loaded onto the wafer chuck 606, the scanner can simultaneously begin inspecting the sample on the wafer chuck 608. This minimizes downtime between scans and maximizes system throughput by preparing the next sample in parallel with the inspection process. While this application describes a 180-degree rotation corresponding to object holders positioned diametrically opposite to each other on a single rotating support structure, other rotation angles may be used. For example, the angle between the object holders may be less or greater than 180 degrees.

[0037] The embodiment shown in Figures 6 and 7 has two (dual) rotatable support structures that support 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 forser assembly may have two forser, one forser, or multiple forser. Furthermore, each transducer mounting base may accommodate one, two, or more transducers. Using fewer wafer chucks on the support structure allows for very precise control of the wafer chucks by the individual swivel mechanism, improving stability and alignment. Furthermore, manufacturing costs may also be reduced. In some embodiments, the support structure can accommodate any number of wafer / package chucks, and similarly, any number of forser and transducer mounting bases can be used for any number of wafer / package chucks.

[0038] Four height-adjustable wafer chucks in two carousels

[0039] Figure 8 shows a wafer chuck assembly 800 with height-adjustable wafer chucks in various representative embodiments. The wafer chuck assembly 800 includes a first rotating support structure 802 that supports height-adjustable wafer chucks 804 and 806, and a second rotating support structure 808 that supports height-adjustable wafer chucks 810 and 812. As described with reference to Figure 5, the upper mounting surface of the wafer chuck may be raised above the water level in the scan tank to allow loading and unloading of wafers and packages, or it may be lowered below the water level in the scan tank for ultrasonic testing. Sample wafers and packages are automatically placed in wafer chucks 804 and 810 by an air transport robot or manually by an operator. After the wafers and packages are loaded into wafer chucks 804 and 810, the system rotates both support structures 180 degrees to position the samples for immediate inspection. The scanning process is initiated to inspect the samples in wafer chucks 804 and 810. Simultaneously, new samples are loaded into wafer chucks 806 and 812. Once the inspection of the samples in wafer chucks 804 and 810 is complete, both support structures rotate 180 degrees back to their original positions, allowing the samples to be unloaded. While the inspected samples on wafer chucks 804 and 810 are being unloaded and new samples are being loaded into wafer chucks 804 and 810, the scanner can simultaneously begin inspecting the samples on wafer chucks 806 and 812. This minimizes downtime between scans and maximizes system throughput by preparing the next sample in parallel with the inspection process. A flexible bellows (corrugated mechanism) 814 may be used to cover and protect the riser mechanism of the object holder.

[0040] In the embodiments shown in Figures 6-8, the two support structures are configured to reduce the size required for the scan tank. In particular, the motor-driven (electric) swivel spindles are positioned such that wafer chucks 806 and 812 in the scan area are located further away from wafer chucks 804 and 810, which are positioned for loading and unloading. With parallel support structures, the distance between the rotation points would need to be increased to maintain the same transducer spacing, which would require a larger tank. In this configuration, there would be insufficient space to rotate the two support structures simultaneously. Movements such as rotation of support structures 802 and 808 may be performed sequentially to ensure sufficient clearance between these support structures. For example, the rotation of one support structure may begin before the rotation of the other support structure, ensuring sufficient clearance between the first and second support structures during rotation.

[0041] Figure 9 is a flowchart of ultrasonic flaw detection method 900 according to various representative embodiments. Figure 9 shows the operation of one or more support structures, each support structure supporting two or more wafer chucks. As mentioned above, one support structure may support three or more wafer chucks, and one or more support structures may be used in the scanner. When two or more support structures are used, each may operate synchronously or sequentially according to flow 900. Referring to Figure 9, in block 902, the wafer to be inspected is removed from a carrier such as a FOUP (Front Opening Unified Pod), pre-aligned with wafer chuck A of the scanner, and dropped onto wafer chuck A. In block 904, the support structures supporting wafer chucks A and B rotate to position wafer chuck A within the scanner's scanning area and wafer chuck B in the loading and unloading position. In block 906, the wafer in wafer chuck A is inspected. While wafer A is being inspected, another wafer (if any) is unloaded (removed) from wafer chuck B and moved to the dryer in block 908. In block 910, the next wafer is taken out of the FOUP, pre-aligned, and placed on wafer chuck B. In block 912, the support structure is rotated again to position wafer chuck B within the scanner's scanning area and wafer chuck A in the loading and unloading position. In block 914, the wafer in wafer chuck B is inspected. While the wafer is being inspected, in block 916, the wafer is unloaded from wafer chuck A and moved to the dryer. In block 918, the next wafer is taken out of the FOUP, pre-aligned, and placed on wafer chuck A. The flow returns to block 904 and is repeated until there are no more wafers to scan, and the scanned wafers are unloaded.

[0042] Block 906 will be implemented in parallel with Blocks 908 and 910. Blocks 916 and 918 will be implemented in parallel with Block 914.

[0043] In some embodiments, method 900 may use multiple support structures simultaneously. In such embodiments, each block of method 900 relating to one support structure may occur simultaneously with a corresponding block relating to another support structure. For example, in block 906, the first wafer in wafer chuck A of the first support structure is inspected, and at the same time, the second wafer in wafer chuck A of the second support structure is inspected. Similarly, in block 908, the third wafer is unloaded in wafer chuck B of the first support structure and moved to the dryer, while the fourth wafer is unloaded in wafer chuck B of the second support structure. Thus, each block of method 900 may occur with multiple support structures. Furthermore, these support structures are configured to ensure rotation without interfering with each other.

[0044] When wafers are automatically loaded and unloaded by a robotic handler, that same handler may also be used to remove the wafers from the dryer and return them to the FOUP or pass them on to another process.

[0045] Wafer handling

[0046] As mentioned above, the object holder may be, for example, a wafer chuck. A wafer chuck is a mechanical, electromechanical, or pneumatic mechanism, or a combination thereof, for securely fixing a semiconductor wafer in the appropriate position during processing. Wafer chucks are essential components of any semiconductor machine because they directly handle wafers for various processes.

[0047] Generally, wafers are classified into "die-less wafers" and "die-attached wafers." Figure 10 shows the first category, wafer 1002, which does not have a die on its surface. Typically, this type of wafer is smooth on both sides. Figure 11 shows the second category, wafer 1104, which has semiconductor dies 1102 attached to its surface. Typically, these wafers have multiple dies attached to one side, and the wafer surface becomes uneven due to the thickness of the dies.

[0048] Both categories of wafers can be used in the same system for processing, scanning, and inspection during manufacturing. Often, different types of wafers ("die-less wafers" and "die-attached wafers") are held using different wafer chucks. In this case, the wafer chuck must be manually changed each time the semiconductor machine switches wafer types. These manual wafer chuck changes result in increased downtime and decreased productivity. Reducing system downtime leads to increased productivity.

[0049] Die-equipped wafers must be picked up using the side of the wafer that does not contain a die, in order to prevent damage to the die. Depending on the application, this may be the top or bottom side. Die-less wafers are usually picked up using the bottom side, but depending on the application, they may be processed using the top side. Therefore, it is beneficial for wafer chucks to work in conjunction with various types of wafer handlers.

[0050] Embodiments of this disclosure provide a wafer chuck configured to hold both types of wafers ("die-equipped wafers" and "die-less wafers") in a single wafer chuck structure. This avoids the need to change wafer chucks when the wafer type changes, and significantly improves throughput. The wafer is held only by its edge, and a riser mechanism lifts the wafer above the wafer chuck as needed to pick up and load the wafer.

[0051] Figure 10 shows wafer 1002 before semiconductor die manufacturing. Die-less wafer 1002 is typically picked up using the bottom surface of the wafer.

[0052] Figure 11 shows a wafer 1100 with a manufactured die 1102. The wafer 1100 may be touched or picked up using the die-free side of the wafer (the top side in the figure). The wafer 1100 also has a "keep out" zone 1104 on the bottom edge of the wafer. If necessary, it is permitted to touch and hold only the bottom edge of the wafer within the keep out zone.

[0053] Figure 12A shows a wafer chuck 1200 having a wafer riser mechanism 1202 according to various representative embodiments. The wafer riser mechanism has pins 1204 for raising and lowering the wafer. The pins 1204 can rise above the outer ring 1206 of the wafer chuck body, as shown in the figure. The wafer riser mechanism can be operated by mechanical, pneumatic, or electromechanical means, for example. The wafer chuck 1200 has an inner ring 1208 that supports the inner region of the wafer.

[0054] Figure 12B shows a further wafer chuck 1220 having a wafer riser mechanism 1202 according to various representative embodiments. The wafer chuck 1220 has an outer ring 1206 to support the outer edge of the wafer, but no inner ring to prevent contact with the die on the wafer.

[0055] Conventional wafer handlers have a recessed ring for handling wafers from below, allowing the handler to be removed after the wafer has been placed in the wafer chuck. The wafer riser disclosed herein allows the handler to be adapted using a complete outer ring without a recess. In one embodiment, the wafer chuck has a complete outer ring that supports the outer portion of the bottom surface of the wafer. Having a complete outer ring allows for finer control of the inspection process, such as optionally immersing the wafer surface in liquid or optionally protecting the wafer edges to minimize water ingress. This depends on the application. This control is not possible with wafer handlers that have a recess, and is therefore an advantage of the wafer riser.

[0056] Figure 13 shows a side view of the wafer chuck 1200 or wafer chuck 1220 according to various representative embodiments. In this figure, the three pins 1204 of the wafer riser mechanism rise to support the wafer 1302.

[0057] Figure 14A is a further diagram of a wafer chuck 1200 having a wafer riser mechanism 1202 according to various representative embodiments. In this diagram, the pins 1204 are lowered to a position on the upper surface of the outer ring 1206 or to a position below the upper surface. The wafer chuck 1200 has an inner ring 1208 that supports the inner region of the wafer.

[0058] Figure 14B shows the corresponding diagram of the wafer chuck 1220 without the inner ring.

[0059] Figure 15 shows a side view of a wafer chuck 1200 or 1220 according to various representative embodiments. In this figure, the wafer 1302 is supported by the upper surface of the outer ring 1206 by the descent of three pins 1204.

[0060] Figure 16 illustrates the operating principle for handling a “die-less wafer” in various representative embodiments. The same operating principle may be used for applications where the die is manufactured on the surface of the wafer. In some embodiments, an end effector (working tip tool) 1602 located at the tip of a robotic arm is used to hold and transport the wafer 1302 from one scan area to another. The end effector 1602 is a gripping tool for automated wafer handling. As shown in configuration (A) of Figure 16, for a die-less wafer, the end effector 1602 holds the wafer 1302 using the bottom surface of the wafer and pre-aligns the wafer with the outer ring 1206 of the wafer chuck, as indicated by arrow 1604. In configuration (B), the end effector descends, as indicated by arrow 1606. This places the wafer 1302 on the pin 1204 of the wafer riser mechanism. In configuration (C), the end effector 1602 is lowered further. In this position, the end effector is positioned between the wafer 1302 and the upper surface of the wafer chuck. This allows the wafer riser mechanism to create sufficient space 1608 between the wafer and the wafer chuck, thereby allowing the end effector to pass between the wafer and the wafer chuck and be pulled out, as shown in configuration (D). After the wafer is placed on the wafer riser mechanism, the wafer riser mechanism is lowered to position the wafer on the outer ring of the wafer chuck, as shown in configuration (E). The wafer is then securely attached to the wafer chuck by vacuum or other similar means.

[0061] Operating principle for handling "wafers with dies"

[0062] Wafers with the die on the top surface may be handled as described above, referring to Figure 16. Alternatively, if the die is on the bottom surface of the wafer, the end effector holds the wafer using the top surface (using a vacuum grip or edge grip), and the wafer is placed in the outer ring of the wafer chuck with the wafer riser in the lowered position. Note that the die is on the bottom surface of the wafer, and the die surface should not be touched when handling the wafer. At this point, the end effector is positioned on the top surface of the wafer. Once the wafer is placed in the outer ring of the wafer chuck, it is securely attached to the wafer chuck by vacuum or other similar means. Here, only the keep-out zone of the wafer is in contact with the outer ring of the wafer chuck.

[0063] Figure 17 is a flowchart of the operation method 1700 of a wafer chuck using a wafer riser according to various representative embodiments. This method may be used for die-less wafers or wafers with a die on the top surface. In block 1702, the wafer riser is raised. In block 1704, a die-less wafer is removed from a FOUP or other holder using a robot's end effector and pre-aligned to the wafer chuck. The wafer is supported on its bottom surface. In block 1706, the end effector is lowered to place the wafer on the wafer riser. In block 1708, the end effector is lowered away from the wafer, and in block 1710, the end effector is withdrawn. In block 1712, the wafer riser is lowered to place the wafer on the wafer chuck, and vacuum is applied to hold the wafer on the wafer chuck. In this way, the same wafer chuck may be used to hold die-on and die-less wafers. As a result, time spent changing wafer chucks can be saved.

[0064] A wafer chuck assembly may include both a holder riser and a wafer riser. The holder riser may operate to raise and lower the object holder above the water level in the scan tank. The wafer riser supports the wafer above the wafer chuck, allowing contact with the underside of the wafer during handling.

[0065] In this description, terms expressing relationships such as first and second, above and below, are used solely to distinguish one entity or action from another, and may be used without necessarily requiring or implying an actual relationship or order between such entities or actions. The terms “comprises,” “comprising,” “includes,” “including,” or other variations are intended to cover non-exclusive inclusion, and a process, method, article, or product consisting of a list of elements does not necessarily include only these elements, but may include other elements that are not explicitly listed or that are specific to such process, method, article, or apparatus. An element referred to in “comprises …a” does not, without further constraint, exclude the presence of additional identical elements in a process, method, article, or apparatus that includes that element.

[0066] Throughout this description, any reference to “one embodiment,” “a particular embodiment,” “a certain embodiment,” “implementation,” “aspect,” or similar terms means that any particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of this disclosure. Therefore, occurrences of such phrases throughout this application or in various places do not necessarily all refer to the same embodiment. Furthermore, any particular feature, structure, or characteristic can be combined in any suitable manner in one or more embodiments without limitation.

[0067] The term "or" as used in this application should be interpreted as meaning comprehensively or any one or any combination thereof. Accordingly, "A, B or C" means any of "A," "B," "C," "A and B," "A and C," "B and C," or "A, B and C." An exception to this definition arises only when the combination of elements, functions, steps, or actions is essentially mutually exclusive.

[0068] As used in this application, the term “configured to perform” means, when applied to an element, that the element may be designed or constructed to perform a specified function or has the necessary structure to enable it to be reconfigured or adapted to perform that function.

[0069] Numerous details have been described to help understand the embodiments described herein. The embodiments may be carried out without these details. In other examples, well-known methods, procedures, and components are not described in detail to avoid obscuring the embodiments described. This disclosure should not be considered to be limited to the embodiments described herein.

[0070] Those skilled in the art will understand that this disclosure is illustrated by examples. This disclosure can be implemented using hardware component equivalents such as dedicated hardware and dedicated processors that are equivalent to the disclosure as described and claimed. Similarly, alternative equivalent embodiments of the disclosure may be constructed using dedicated processors and dedicated hardwired logic.

[0071] The various embodiments described herein are implemented using dedicated hardware, configuration-modular hardware, or programmed processors that execute programming instructions, which are broadly described in the form of flowcharts, and which may be stored in any suitable electronic storage medium or transmitted via any suitable electronic communication medium. These elements may be used in combination. Those skilled in the art will understand that the processes and mechanisms described above may be implemented in any number of modifications without departing from the disclosure. For example, without departing from the disclosure, the order of certain steps performed can often be changed, additional steps can be added, and steps can be removed. Such modifications are considered equivalent.

[0072] The various representative embodiments described in detail in this application are presented as examples and are not limiting. Those skilled in the art will understand that by making various modifications to the forms and details of the described embodiments, equivalent embodiments that remain within the scope of the appended claims can be obtained.

Claims

1. An ultrasonic flaw detection system, One or more ultrasound scan areas, One or more support structures that are movable between the first and second configurations, A plurality of object holders, each comprising at least first and second object holders, which are coupled to one of the support structures and configured to hold an object to be ultrasonically scanned, and Equipped with, In the first arrangement of the support structure described above, the first object holder is positioned to allow loading and unloading of the first object holder, and the second object holder is positioned within one of the one or more ultrasonic scanning areas. An ultrasonic flaw detection system in which, in the second arrangement of the support structure described above, the second object holder is arranged to enable loading and unloading of the second object holder, and the first object holder is arranged within one of the one or more ultrasonic scanning areas.

2. The ultrasonic flaw detection system according to claim 1, wherein at least one of the multiple object holders is a wafer chuck configured to hold a semiconductor wafer to be ultrasonically scanned.

3. The ultrasonic flaw detection system according to claim 1, wherein one of the support structures described above is coupled to a plurality of object holders.

4. The ultrasonic flaw detection system according to claim 1, wherein one or more ultrasonic scanning areas have two ultrasonic scanning areas, and one or more support structures have two support structures.

5. The ultrasonic flaw detection system according to claim 1, wherein one of the ultrasonic scanning areas among the one or more ultrasonic scanning areas described above includes an ultrasonic transducer and a water coupler.

6. The ultrasonic flaw detection system according to claim 1, further comprising a scan tank, wherein an object holder positioned within the ultrasonic scan area is configured to hold an object in the scan tank.

7. The ultrasonic flaw detection system according to claim 6, wherein the object holder is connected to the support structure by one or more holder risers configured to move the object holder between a first position above the water level in the scan tank for loading and unloading and a second position below the water level in the scan tank for performing ultrasonic scanning.

8. The ultrasonic flaw detection system according to claim 6, wherein the object holder is connected to the support structure by two or more holder risers configured to adjust the tilt of the object holder in one ultrasonic scanning area among the one or more scanning areas.

9. One of the object holders among the multiple object holders described above is a wafer chuck, and the ultrasonic flaw detection system described above is It is placed in the peripheral region of the wafer chuck mentioned above, The semiconductor wafer is supported at a first position above the wafer chuck, allowing the robot's positioning arm to pass between the wafer chuck and the lower surface of the semiconductor wafer. The ultrasonic flaw detection system according to claim 1, further comprising a plurality of wafer risers configured to move to a second position below the first position, so that the semiconductor wafer can be supported on its lower surface by the wafer chuck.

10. The ultrasonic flaw detection system according to claim 9, wherein the wafer chuck has a non-defective outer ring for supporting the outer region of the wafer.

11. The ultrasonic flaw detection system according to claim 1, wherein the support structure includes a rotatable index table.

12. An ultrasonic scanning method for scanning multiple objects in an ultrasonic flaw detection system, The process involves moving the support structure to a first position, positioning the first object holder connected to the support structure outside the ultrasonic scanning area of ​​the ultrasonic flaw detection system, and positioning the second object holder connected to the support structure inside the ultrasonic scanning area. The process involves performing an ultrasonic scan of the object in the second object holder described above, The process of unloading scanned objects from the first object holder mentioned above, A process of loading one of the above multiple objects to be scanned into the first object holder, The process involves moving the support structure to a second position, placing the first object holder within the ultrasonic scanning area, and placing the second object holder outside the ultrasonic scanning area. The process involves performing an ultrasonic scan of the object in the first object holder described above, The process of unloading scanned objects from the second object holder mentioned above, The process of loading the object to be scanned into the second object holder mentioned above. An ultrasonic scanning method that includes [the following features].

13. The movement includes rotation, and the support structure is a first support structure and a second support structure and a first support structure of an ultrasonic flaw detection system having two ultrasonic scanning areas, further comprising the process of rotating the first support structure and then rotating the second support structure in order to ensure sufficient clearance between the first and second support structures when rotating, according to claim 12.

14. The above-mentioned support structure is a first support structure and a second support structure, and is the first support structure of an ultrasonic flaw detection system having two ultrasonic scanning areas. The process involves moving the second support structure to the first position, positioning the third object holder connected to the second support structure outside the ultrasonic scanning area of ​​the ultrasonic flaw detection system, and positioning the fourth object holder connected to the second support structure inside the ultrasonic scanning area. The process involves performing an ultrasonic scan of the object within the fourth object holder described above, The process of unloading scanned objects from the third object holder mentioned above, A process of loading one of the above multiple objects to be scanned into the third object holder, The process involves moving the second support structure to the second position, placing the third object holder within the ultrasonic scanning area, and placing the fourth object holder outside the ultrasonic scanning area. The process involves performing an ultrasonic scan of the object in the third object holder described above, The process of unloading scanned objects from the fourth object holder described above, The process of loading the object to be scanned into the fourth object holder mentioned above. The method of claim 12, further comprising the above.

15. The process involves raising the first object holder outside the water tank and unloading the scanned object from the first object holder. The process involves lowering the first object holder into the water tank and scanning the objects within the first object holder. The process involves raising the second object holder outside the water tank and unloading the scanned object from the second object holder. The process involves lowering the second object holder into the water tank and scanning the objects within the second object holder. The method of claim 12, further comprising the above.

16. The method of claim 12, wherein the process of raising and lowering the first object holder includes the process of operating one or more holder risers that connect the first object holder and the support structure.

17. The method of claim 12, wherein the process of raising and lowering the first object holder includes a process of connecting the first object holder and the support structure and operating a plurality of holder risers arranged in the area surrounding the first object holder.

18. The method of claim 17, further comprising the process of adjusting the arrangement of the first object holder using the above-mentioned plurality of holder risers.

19. The above first object holder is a wafer chuck, and the above method is A process to raise multiple wafer risers arranged in the peripheral region of the wafer chuck, A process of placing the semiconductor wafers on the plurality of wafer risers using a robot positioning arm positioned between the lower surface of the semiconductor wafer and the upper surface of the wafer chuck, The process of withdrawing the positioning arm of the above robot, The process involves lowering the multiple wafer risers described above to position the lower surface of the semiconductor wafer on the upper surface of the wafer chuck. The method of claim 12, further comprising the above.

20. In the first arrangement described above, the process of arranging the third object holder connected to the support structure outside the second ultrasonic scanning area of ​​the ultrasonic flaw detection system, and arranging the fourth object holder connected to the support structure inside the second ultrasonic scanning area, In the second arrangement described above, the process involves placing the third object holder within the second ultrasonic scanning area and the fourth object holder outside the second ultrasonic scanning area. The method of claim 12, comprising:

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