Warp inspection device and warp inspection method

Abstract

The invention relates to a warpage checking device and to an associated method. The apparatus includes a support frame having an upper support surface; a mobile station mounted on the support surface; a chuck attached to the moving table; wherein the chuck comprises a set of movable lift pins movable between a first position in which the lift pins sink into the chuck and a second position in which the lift pins protrude from the chuck; a holding device attached to the support frame; and an optical sensor arrangement arranged to measure warpage of the disc-shaped workpiece in a first measurement mode in which the lift pin is in the first position and in a second measurement mode in which the lift pin is in the second position.

Description

TECHNICAL FIELD

[0001] The present invention relates to a warpage inspection apparatus and a warpage inspection method for disc-shaped workpieces, in particular semiconductor or mold wafers. BACKGROUND

[0002] Fan-out wafer-level packaging (FOWLP) has emerged as an advanced packaging technology for semiconductor devices, especially for mobile and IoT applications.

[0003] Fan-out wafer-level packaging (FOWLP) technology has gained wide popularity due to its many advantages, including improved thermal and electrical performance, support for multi-die configurations, and high-density routing. Many package solution providers have adopted the technology to facilitate the development of high-performance devices.

[0004] However, the technology has two well-known issues: die shift and warpage. Die shift refers to the offset of a die compared to its designed position, while warpage is a deformation of the wafer caused by a mismatch of the coefficient of thermal expansion (CTE) between the semiconductor and the mold. Warpage can cause significant problems during high-volume manufacturing, as it hinders the smooth handling of the wafer on different platforms from a flat stage to a pin-up position, as well as the end-of-arm tooling of the transport robot.

[0005] To address the warpage issue, a warpage reduction process can be employed, or the structure of the wafer can be changed to achieve a feasible deformation amplitude. However, in choosing the appropriate combination of structures, such as a thicker semiconductor, a thicker overmold, or an increased die-to-die spacing, it is crucial to understand the behavior of the wafer at different stages. For example, a thin wafer can sag in the middle if placed in a large-diameter end-of-arm tooling, but can sag at the edges when placed in a stage pin-up position. The warpage profile observed on different platforms varies significantly, and these variations are often related to the structure of the wafer.

[0006] Understanding warpage is essential to ensure the quality and reliability of the packaged devices. By monitoring and measuring warpage during the FOWLP process, manufacturers can identify and address issues before they become major difficulties. For example, measuring warpage can help determine the optimal die placement on the substrate, ensuring that the dies are not stressed, and the final packaged device has the desired properties.

[0007] Furthermore, understanding the causes and effects of warpage can help in the design of the FOWLP process as well as the selection of machines and process optimization, ensuring that they can withstand the stresses and strains of the process.

[0008] Warpage can manifest in a variety of forms, including bending, twisting, and curling. There are multiple causes of warpage, including coefficient of thermal expansion (CTE) mismatch between the substrate and die, residual stress, and material properties.

[0009] As FOWLP technology continues to be used for core and high-end applications, it becomes imperative to optimize processing capabilities through warpage characterization.

[0010] US8599366B2 discloses a method and apparatus for determining the deformation of a disc-shaped workpiece, in particular a semiconductor or molded wafer.

[0011] JP2018179680A discloses an information acquisition device for acquiring information about a surface of an inspection object and a control device for determining a surface condition of the inspection object based on information acquired by the information acquisition device. A distance measuring unit is used to focus on the surface of the object to be inspected, wherein a control unit is configured to be able to detect warpage of the object to be inspected based on distance measurement results of the distance measuring unit.

[0012] JP2012193968A discloses a warpage inspection device and a warpage inspection method for inspecting warpage occurring in an inspection object (e.g., a ceramic substrate) formed in a flat shape. SUMMARY

[0013] It is an object of the present invention to provide an improved warpage inspection device and warpage inspection method, in particular for semiconductor or molded wafers, which can accurately characterize wafer warpage response for different platforms.

[0014] The present invention provides a warpage inspection device according to independent claim 1 and a warpage inspection method according to independent claim 19, for disc-shaped workpieces, in particular semiconductor or molded wafers.

[0015] Advantageously, the present invention provides a non-contact metrology tool that employs advanced optical scanning technology to accurately measure wafer deformation in multiple different platforms. It provides a comprehensive and precise analysis of wafer warpage, which is critical to ensuring the quality of semiconductor devices.

[0016] The warpage inspection device according to the present invention uses an optical scanner, which preferably has high resolution and captures surface data of the wafer at multiple points or locations, enabling it to generate accurate 2D and / or 3D maps of the wafer surface. The software algorithms of the system then analyze the collected data to accurately calculate the warpage profile of the wafer, including the curvature and thickness variations of the wafer.

[0017] Preferably, the view can be rotated, zoomed and manipulated, thereby allowing the user to observe the warpage profile from different angles and assess its impact on wafer performance. Preferably, the software can generate reports and graphs that help the user to interpret the measurement results and make informed decisions. The apparatus is easy to use, with a user-friendly interface that allows for quick and efficient measurement setup and execution. The non-contact operation of the tool also reduces the risk of contamination and damage to the wafer, thereby ensuring that the measurement results are accurate and reliable.

[0018] Performing the measurements at different platforms allows the user to predict and simulate the warpage behavior of the wafer at different processing stages. Preferably, the changes of the different platforms and the measurements thereon are performed automatically without user intervention. This information can be used to adjust the robot, the transportation method and the hardware design, thereby eliminating wafer process deviations.

[0019] Preferred embodiments are listed in the respective dependent claims.

[0020] According to a preferred embodiment, the warpage inspection apparatus further comprises a fork-shaped end effector connected or connectable to the mobile stage for mounting the disc-shaped workpiece, wherein the optical sensor apparatus is arranged to measure the warpage of the disc-shaped workpiece at a plurality of positions on the disc-shaped workpiece in a third measurement mode with the disc-shaped workpiece mounted on the end effector. This information is useful when utilizing a robot using the end effector in later manufacturing processes.

[0021] According to another preferred embodiment, the support frame comprises a lower body portion to be placed on the ground and comprises an upper plate portion, the lower body portion and the upper plate portion being coupled together by adjustable levelling means for levelling the xy-plane. Thus, the measurements can be performed in a levelled xy-plane.

[0022] According to another preferred embodiment, the warpage inspection apparatus further comprises a measurement controller for controlling the lift pins and the optical sensor apparatus and the mobile stage in the respective measurement modes.

[0023] According to another preferred embodiment, the warpage inspection apparatus further comprises a vacuum system connected to the chuck and a vacuum controller for controlling the vacuum system in the first measurement mode. This makes it possible to perform the first measurement mode with or without vacuum suction.

[0024] According to another preferred embodiment, the vacuum system is connected or connectable to the end effector.

[0025] According to another preferred embodiment, the end effector comprises a first branch and a second branch, and a plurality of pairs of vacuum suction holes are oppositely arranged at different length positions of the first branch and the second branch.

[0026] According to another preferred embodiment, the vacuum controller is arranged to selectively evacuate each pair of vacuum suction holes in the third measurement mode. Thus, in the third measurement mode, various measurements can be performed by chuck mounting through different pairs of vacuum suction holes.

[0027] According to another preferred embodiment, the warpage inspection apparatus further comprises a temperature control system connected to the chuck and a temperature controller for controlling the temperature control system in the first measurement mode. Thus, the first measurement mode can be performed at different temperatures.

[0028] According to another preferred embodiment, the measurement controller and / or the vacuum controller and / or the temperature controller are arranged in the support frame, in particular in the lower body portion of the support frame.

[0029] According to another preferred embodiment, the warpage inspection apparatus further comprises a display apparatus controllable by the measurement controller for displaying the measurement results of the measurement modes as two-dimensional and / or three-dimensional views. This makes it easier to intuitively understand the measurement data.

[0030] According to another preferred embodiment, the warpage inspection apparatus further comprises an input apparatus for selecting the measurement modes and the sequence of measurement modes.

[0031] According to another preferred embodiment, the input apparatus is arranged to manipulate the views such that they can be rotated and zoomed, thereby allowing the user to observe the measured warpage profile of the disc-shaped workpiece from different perspectives. This further contributes to the understanding of the measurement data.

[0032] According to another preferred embodiment, the chuck comprises a plurality of groups of movable lift pins arranged symmetrically or asymmetrically along different concentric circles on the chuck, which can be individually controlled by the measurement controller to lift the disc-shaped workpiece in the second measurement mode. Thus, in the second measurement mode, different measurements can be performed with different groups of lift pins being lifted.

[0033] According to another preferred embodiment, the fork-shaped end effector can be manually connected to the mobile stage by a connector.

[0034] According to another preferred embodiment, the fork-shaped end effector is connected to the mobile stage by a movable connector arranged to lift the disc-shaped workpiece from the lift pins in order to bring it into the second measurement mode.

[0035] According to another preferred embodiment, the optical sensor apparatus comprises a multi-color confocal camera. This contributes to obtaining accurate high-resolution data.

[0036] According to another preferred embodiment, the optical sensor device is mounted on a holder, which is adjustable in z-direction to adjust the distance to the disc-shaped workpiece in the respective measurement mode. BRIEF DESCRIPTION OF DRAWINGS

[0037] In the following, preferred embodiments of the present application are described in conjunction with the drawings.

[0038] In the drawings:

[0039] Figure 1a ), a schematic top view, Figure 1b ) shows a schematic front view, Figure 1a ) shows a schematic perspective view; Figure 1b

[0040] Figure 2 a) to c) of Fig. 1 show partial perspective views of three different wafer platforms to be used in a warpage inspection device according to an embodiment of the present application, namely, Figure 2 a) of Fig. 1 shows a chuck as a platform, wherein the lift pins sink into the chuck in a first measurement mode, Figure 2 b) of Fig. 1 shows a lift pin as a platform, wherein the lift pin protrudes from the chuck in a second measurement mode, Figure 2 c) of Fig. 1 shows an end effector as a platform in a third measurement mode;

[0041] Figure 3 shows a more detailed top view of the end effector and a connector to be used in a warpage inspection device according to a first embodiment of the present application for connecting the end effector to a mobile station;

[0042] Figure 4 shows Figure 3 a perspective view of the end effector of Fig. 1, wherein the connector is connected to the mobile station;

[0043] Figure 5 shows a schematic perspective view of a warpage inspection device according to a second embodiment of the present application;

[0044] Figure 6 a), b) of Fig. 2 show top views of two different chucks to be used in a warpage inspection device according to an embodiment of the present application, namely, Figure 6 a) of Fig. 2 shows a first chuck with an asymmetric lift pin arrangement, Figure 6 b) of Fig. 2 shows a second chuck with a symmetric lift pin arrangement;

[0045] Figure 7 ​a) and b) show perspective views of an end effector and a movable connector for connecting the end effector to a moving stage, which will be used in a warp inspection apparatus according to a third embodiment of the invention. Figure 7 a) shows the retracted position of the end effector. Figure 7 b) shows the extended position of the end effector; and

[0046] Figure 8 A flowchart of a warpage inspection method according to a fourth embodiment of the present invention is shown.

[0047] In the accompanying drawings, the same reference numerals denote the same or functionally equivalent parts. Detailed Implementation

[0048] Figure 1a ), Figure 1b The diagram shows a warpage inspection apparatus according to a first embodiment of the present invention, namely, Figure 1a A schematic front view is shown. Figure 1b A schematic 3D diagram is shown.

[0049] The warpage inspection device according to the first embodiment is suitable for disk-shaped workpieces in the form of molded wafers.

[0050] It includes a support frame 1 having an upper support surface 1a defining an xy-plane. The support frame 1 includes a lower body portion 5 and an upper plate portion 10. The lower body portion 5 has a plurality of legs 100 to be placed on the ground. The lower body portion 5 and the upper plate portion 10 are connected together by an adjustable leveling device 12 for leveling the xy-plane. The leveling device 12 may include rotatable bolts.

[0051] The movable stage 20 is mounted on the support surface 1a and is movable in the xy plane, for example by a cross sliding mechanism that slides on orthogonal tracks 20a and 20b (see [link]). Figure 1b It moves in the xy plane.

[0052] Vacuum chuck 30 is attached to the upper side of the moving stage 20. Vacuum chuck 30 includes a set of movable lifting pins 30a, 30b, and 30c (see...). Figure 2 (b) The set of movable lifting pins can move between a first position and a second position. In the first position, the lifting pins 30a, 30b, and 30c are recessed into the chuck 30 to mount the molded wafer 40 onto the chuck 30. In the second position, the lifting pins 30a, 30b, and 30c extend from the chuck 30 to lift the molded wafer 40 from the chuck 30 in the z direction perpendicular to the xy plane.

[0053] In a first embodiment, the holding device 45 attached to the support frame 1 forms a bridge. The optical sensor device 49 is attached to the bridge-like holding device 45 by means of a holder 50, which is adjustable in the z-direction to adjust the distance to the disc-shaped workpiece in the respective measurement mode. The optical sensor device 49 comprises a multi-color confocal camera, which emits light 52 to the surface of the molded wafer 40 and receives the reflected light 52 to measure the surface profile of the molded wafer to determine its warping.

[0054] A measurement controller 5a for controlling the lifting pins 30a, 30b, 30c and the optical sensor device 49 and the moving table 20 in the respective measurement mode is accommodated in the lower body portion 5 of the support frame 1. For the sake of simplicity, the corresponding electrical connections are not shown here.

[0055] A vacuum system (not shown) and a vacuum controller 5b for controlling the vacuum system are also accommodated in the lower body portion 5 of the support frame 1. The vacuum system is connected to the chuck 30 and the vacuum controller 5b for controlling the vacuum system. For the sake of simplicity, the corresponding fluid and electrical connections are not shown here either.

[0056] A temperature control system (not shown) and a temperature controller 5c for controlling the temperature control system are also accommodated in the lower body portion 5 of the support frame 1. The temperature control system is connected to the chuck 30 and the temperature controller 5c for controlling the temperature control system to bring the chuck to a selectable temperature during the measurement mode. For the sake of simplicity, the corresponding fluid and electrical connections are not shown here either.

[0057] An input device 70 (e.g. a keyboard) for initiating and selecting the measurement mode and an interface 71 for outputting the measurement data to an external device (e.g. a personal computer) are also included in the lower body portion 5 of the support frame 1.

[0058] The optical sensor device 49 controlled by the measurement controller 5a is arranged to measure the warping of the disc-shaped workpiece 40 at a plurality of positions on the molded wafer in a first measurement mode in which the lifting pins 30a, 30b, 30c of the chuck 30 are in a first position and in a second measurement mode in which the lifting pins 30a, 30b, 30c are in a second position.

[0059] As will be explained below with reference to Figure 2 c), Figure 3 and Figure 4As further explained, the warpage inspection apparatus also includes a forked end effector 35, which is connectable to the stage 20 for mounting the molded wafer 40, and an optical sensor device 49, controlled by the measurement controller 5a, is arranged to measure the warpage of the molded wafer 40 at multiple locations on the molded wafer 40 in a third measurement mode where the molded wafer 40 is mounted on the end effector 35. A vacuum system may be connected to the end effector 35 via fluid lines not shown here.

[0060] Once the molded wafer 40 is placed on the chuck 30, either manually or automatically, the user can input the desired measurement mode sequence via the input device 70, which is then automatically controlled by the software of the measurement controller 5a. The measurement results are output via the interface 70. The next molded wafer 40 can then be placed on the chuck 30, and the same measurement mode sequence can be repeated, or a new measurement mode sequence can be input. If the measurement mode sequence in this first embodiment includes a third measurement mode, the user will be prompted to manually connect the end effector 35 to the stage 20 and place the molded wafer 40 on it.

[0061] The measurement mode sequence can be selected, allowing certain parameters to be predetermined for each measurement mode. For the first measurement mode, temperature and vacuum state can be selected. For the second measurement mode, the lifting pin arrangement can be selected (see...). Figure 6 (a) and (b)). For the third measurement mode, a vacuum suction port pair can be selected (see...). Figure 3 This provides users with a high degree of flexibility in defining measurement modes and mode sequences.

[0062] Figure 2 Images a) through c) show partial perspective views of three different wafer platforms that will be used in a warp inspection apparatus according to an embodiment of the invention.

[0063] according to Figure 2 (a) The chuck 30 serves as a platform for the molded wafer 40 in the first measurement mode (the lifting pin is recessed into the chuck 30), according to Figure 2 (b) The extended lifting pins 30a, 30b, and 30c serve as a platform for the molded wafer 40 in the second measurement mode, according to Figure 2 (c) The end effector 35 is used as a platform for the molded wafer 40 in the third measurement mode.

[0064] Figure 3 A more detailed top view is shown of the end effector and the connector for connecting the end effector to the moving stage, which will be used in the warp inspection apparatus according to a first embodiment of the invention. Figure 4 It shows Figure 3a perspective view of the end effector, wherein the connector is connected to the mobile stage.

[0065] As Figure 3 shown, the end effector 35 comprises a first branch 38a and a second branch 38b, wherein pairs of vacuum suction holes 35a, 35b and 35c, 35d and 35e, 35f are oppositely arranged at different length positions of the first branch 38a and the second branch 38b. The vacuum controller 5b is arranged to selectively evacuate each pair of vacuum suction holes 35a, 35b and 35c, 35d and 35e, 35f in the third measurement mode.

[0066] As Figure 4 shown, the connector 38 can be attached to the mobile stage 20, e.g. by a plug-in mechanism. The vacuum system is connected through corresponding fluid lines (not shown here) provided in the connector 38 and the mobile stage 20.

[0067] Figure 5 a schematic perspective view of a warpage inspection apparatus according to a second embodiment of the application is shown.

[0068] The warpage inspection apparatus according to the second embodiment differs from the warpage inspection apparatus according to the first embodiment in that, as an alternative or in addition to the interface 71, it comprises a display apparatus 60 controllable by the measurement controller 5a for displaying the measurement results of the measurement modes as two- and / or three-dimensional views.

[0069] The input apparatus 70 is arranged to manipulate the views such that they can be rotated and zoomed, thereby allowing the user to observe the measured warpage profile of the disc-shaped workpiece from different viewing angles.

[0070] Further, the holding apparatus 45' is formed by an angular profile, instead of being a bridge as in the first embodiment.

[0071] In other respects, the second embodiment is designed exactly the same as the first embodiment.

[0072] Figure 6 a), b) show top views of two different chucks to be used in a warpage inspection apparatus according to an embodiment of the application, namely, Figure 6 a) shows a first chuck with an asymmetric arrangement of lift pins, Figure 6 b) shows a second chuck with a symmetric arrangement of lift pins.

[0073] Figure 6The first chuck 30 of a) comprises three groups of movable lift pins 29a, 29b, 29c and 30a, 30b, 30c and 31a, 31b, 31c arranged asymmetrically along three different concentric circles D1, D2, D3 on the chuck 30, which are individually controllable by the measurement controller 5a in the second measurement mode to lift the molded wafer 40.

[0074] Figure 6 The second chuck 30 of b) comprises three groups of movable lift pins 29a, 29b, 29c and 30a, 30b, 30c and 31a, 31b, 31c arranged symmetrically along three different concentric circles D1, D2, D3 on the chuck 30, which are individually controllable by the measurement controller 5a in the second measurement mode to lift the molded wafer 40.

[0075] Figure 7 a), b) show perspective views of an end effector and of a movable connector for connecting the end effector to a mobile stage to be used in a warping inspection device according to a third embodiment of the application, Figure 7 a) shows the end effector in a retracted position, Figure 7 b) shows the end effector in an extended position.

[0076] The warping inspection device according to the third embodiment differs from the warping inspection device according to the first embodiment in that:

[0077] The fork-shaped end effector 35 is connected to the mobile stage 20 by a movable connector 38’ arranged to lift the disc-shaped workpiece from the lift pins 30a, 30b, 30c in order to automatically enter the third measurement mode.

[0078] By the connector 38’, the end effector 35 can be moved back and forth along the direction b. According to Figure 7 a), the end effector 35 is retracted and the molded wafer 40 rests on the lift pins 30a, 30b, 30c in the second position for the second measurement mode. According to Figure 7 b), the end effector 35 is extended under the molded wafer 40 which still rests on the lift pins 30a, 30b, 30c. Then when the lift pins 30a, 30, 30c sink into the chuck 30, the molded wafer 40 rests on the end effector 35 and is ready for the third measurement mode.

[0079] As indicated by the dashed line 29, the connector 38’ is directly or indirectly coupled to the mobile stage 20 so that the molded wafer 40 resting on the end effector 35 can be brought to a plurality of measurement positions under the optical sensor device 49.

[0080] In other aspects, the third embodiment is designed to be exactly the same as the first embodiment.

[0081] Figure 8 A flowchart of the warpage inspection method according to the fourth embodiment of the present application is shown.

[0082] In step S1, the molded wafer is placed - manually or automatically - on the chuck 30 of the warpage inspection device of any of the previously described embodiments.

[0083] In step S2, the user can input the desired sequence of measurement modes and their parameters through the input device 70, which will then be automatically controlled by the software of the measurement controller 5a, as already explained above.

[0084] For example, if the first measurement mode without vacuum and the second measurement mode with lift pins 30a, 30b, 30c are selected, the user can start the sequence of measurement modes in step S3.

[0085] In step S4, the warpage of the molded wafer 40 is measured at a plurality of positions on the molded wafer 40 in the first measurement mode with the lift pins 30 in the first position without vacuum.

[0086] In step S5, the process automatically enters the second measurement mode by lifting the lift pins 30a, 30b, 30c.

[0087] In step S6, the warpage of the molded wafer 40 is measured at a plurality of positions on the molded wafer 40 in the second measurement mode with the lift pins 30a, 30b, 30c in the second position.

[0088] In step S7, the user can complete the process through the input device 70 or add another measurement mode. If no further measurement mode is selected, the process ends in step S8.

[0089] If another measurement mode, for example a third measurement mode, is selected, in step S9 the effector 35 is connected to the moving table 20 and the molded wafer 40 is placed on this effector 35 manually or through the movable connector 38' arranged to lift the molded wafer 40 from the lift pins 30a, 30b, 30c in order to bring it into the third measurement mode.

[0090] In step S10, the warpage of the molded wafer 40 is measured at a plurality of positions on the molded wafer 40 in the third measurement mode with the molded wafer 40 mounted on the end effector 35.

[0091] Then, the process ends in step S11.

[0092] Although the application has been described with reference to particular embodiments, the application is not limited to these. Various modifications are possible within the scope of the application as defined in the appended claims.

[0093] In particular, the warp inspection device and method can be applied not only to molded wafers, but also to semiconductor wafers, and most generally to any disc-shaped workpiece that has to be measured for warp.

Claims

1. A warp inspection apparatus for disc-shaped workpieces, in particular semiconductor or molded wafers, comprising: a support frame (1; 5, 10) having an upper support surface (la) defining an xy-plane; a mobile stage (20) mounted on the support surface (la), the mobile stage (20) being movable in the xy-plane; a chuck (30) attached to the mobile stage (20); wherein the chuck (30) comprises a set of movable lift pins (30a, 30b, 30c) movable between a first position in which the lift pins (30a, 30b, 30c) sink into the chuck (30) for mounting the disc-shaped workpiece (40) on the chuck (30) and a second position in which the lift pins (30a, 30b, 30c) protrude from the chuck (30) for lifting the disc-shaped workpiece (40) from the chuck (30) in a z-direction perpendicular to the xy-plane; a holding device (45; 45') attached to the support frame (1; 5, 10); an optical sensor device (49) attached to the holding device (45), the optical sensor device (49) being arranged to measure a warp of the disc-shaped workpiece (40) at a plurality of positions on the disc-shaped workpiece (40) in a first measurement mode with the lift pins (30a, 30b, 30c) in the first position and in a second measurement mode with the lift pins (30a, 30b, 30c) in the second position.

2. The warp inspection apparatus according to claim 1, further comprising a fork-shaped end effector (35) connected or connectable to the mobile stage (20) for mounting the disc-shaped workpiece (40), wherein the optical sensor device (49) is arranged to measure a warp of the disc-shaped workpiece (40) at a plurality of positions on the disc-shaped workpiece (40) in a third measurement mode with the disc-shaped workpiece (40) mounted on the end effector (35).

3. The warp inspection apparatus according to claim 1 or 2, wherein the support frame (1; 5, 10) comprises a lower body portion (5) to be placed on the ground and comprises an upper plate portion (10), the lower body portion (5) and the upper plate portion (10) being coupled together by adjustable levelling devices (12) for levelling the xy-plane.

4. The warp inspection apparatus according to any one of the preceding claims, further comprising a measurement controller (5a) for controlling the lift pins (30a, 30b, 30c) and the optical sensor device (49) and the mobile stage (20) in the respective measurement modes.

5. The warp inspection apparatus according to any one of the preceding claims, further comprising a vacuum system connected to the chuck (30) and a vacuum controller (5b) for controlling the vacuum system in the first measurement mode. ​ 6. The warp inspection device according to claim 5 when dependent on claim 2, wherein the vacuum system is connected or connectable to the end effector (35).

7. The warp inspection device according to claim 6, wherein the end effector (35) comprises a first branch (38a) and a second branch (38b), and wherein pairs of vacuum suction holes (35a, 35b; 35c, 35d; 35e, 35f) are oppositely arranged at different length positions of the first branch (38a) and the second branch (38b).

8. The warp inspection device according to claim 7, wherein the vacuum controller (5b) is arranged to selectively vacuum each pair of vacuum suction holes (35a, 35b; 35c, 35d; 35e, 35f) in the third measurement mode.

9. The warp inspection device according to any one of the preceding claims, further comprising a temperature control system connected to the chuck (30) and a temperature controller (5c) for controlling the temperature control system in the first measurement mode.

10. The warp inspection device according to any one of the preceding claims, wherein the measurement controller (5a) and / or the vacuum controller (5b) and / or the temperature controller (5c) are arranged in the support frame (1; 5, 10), in particular in the lower body portion (5) of the support frame (1; 5, 10).

11. The warp inspection device according to any one of the preceding claims, further comprising a display device (60) controllable by the measurement controller (5a) for displaying the measurement results of the measurement mode as a two-dimensional and / or three- dimensional view.

12. The warp inspection device according to any one of the preceding claims, further comprising an input device (70) for selecting the measurement mode and measurement mode sequence.

13. The warp inspection device according to claim 12 when dependent on claim 11, wherein the input device (70) is arranged to manipulate the view such that the view can be rotated and zoomed, thereby allowing a user to observe the measured warp profile of the disc-shaped workpiece from different viewing angles.

14. The warp inspection device according to claim 4, wherein the chuck (30) comprises a plurality of sets of movable lift pins (29a, 29b, 29c; 30a, 30b, 30c; 31a, 31b, 31c) symmetrically or asymmetrically arranged along different concentric circles (D1, D2, D3) on the chuck (30), which are individually controllable by the measurement controller to lift the disc-shaped workpiece in the second measurement mode.

15. The warp inspection device according to claim 2, wherein the fork-shaped end effector (35) is manually connectable to the mobile stage (20) by a connector (38).

16. The warp inspection apparatus according to claim 2, wherein the fork-shaped end effector (35) is connected to the mobile stage (20) by a movable connector (38') arranged to lift the disc-shaped workpiece from the lifting pins (30a, 30b, 30c) in order to bring it into the third measurement mode.

17. The warp inspection apparatus according to any of the preceding claims, wherein the optical sensor device (49) comprises a polychromatic confocal camera.

18. The warp inspection apparatus according to claim 17, wherein the optical sensor device (49) is mounted on a holder (50) which is adjustable in z-direction to adjust the distance from the disc-shaped workpiece in the respective measurement mode.

19. A warp inspection method for disc-shaped workpieces, using a warp inspection system according to any of the preceding claims, and comprising the steps of: measuring the warp of the disc-shaped workpiece (40) at a plurality of positions on the disc-shaped workpiece (40) in the first measurement mode with the lifting pins (30a, 30b, 30c) in the first position; automatically entering the second measurement mode; measuring the warp of the disc-shaped workpiece (40) at a plurality of positions on the disc-shaped workpiece (40) in the second measurement mode with the lifting pins (30a, 30b, 30c) in the second position.

20. The warp inspection method according to claim 19, wherein the warp inspection system further comprises a fork-shaped end effector (35) connected or connectable to the mobile stage (20) for mounting the disc-shaped workpiece (40), wherein the optical sensor device (49) is arranged to measure the warp of the disc-shaped workpiece (40) at a plurality of positions on the disc-shaped workpiece (40) in a third measurement mode with the disc-shaped workpiece (40) mounted on the end effector (35), The warpage inspection method further comprises the following steps: automatically or manually entering the third measurement mode, and measuring the warp of the disc-shaped workpiece (40) at a plurality of positions on the disc-shaped workpiece (40) in the third measurement mode with the disc-shaped workpiece (40) mounted on the end effector (35).

Images