Wafer chuck displacement amount confirmation method, wafer chuck, and prober

Abstract

In the present invention, a control device executes: a movement step for moving, in the Y-axis direction, a wafer chuck provided with a plurality of marks on an upper surface thereof; and a displacement amount measurement step for measuring a displacement amount ΔX by which the plurality of marks are displaced in the X-axis direction relative to a predetermined true value along the Y-axis direction.

Description

Wafer chuck displacement amount confirmation method, wafer chuck, and prober

[0001] The present disclosure relates to a wafer chuck displacement amount confirmation method, a wafer chuck, and a prober.

[0002] In a prober used for inspecting electrical characteristics of semiconductor chips formed on a wafer, when moving a wafer chuck carrying a wafer in the Y-axis direction, the wafer chuck may be displaced in the X-axis direction orthogonal to the Y-axis direction, that is, deviated from a true value, due to factors such as the adjustment state of the prober's leg positions and aging changes. If this displacement amount is large, the wafer chuck cannot be moved straight, which affects contact with probe needles.

[0003] Conventionally, a special wafer having marks arranged at regular intervals (hereinafter referred to as "accuracy confirmation wafer") is placed on a wafer chuck to confirm the displacement amount of the wafer chuck. For example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2010-019742) discloses a technique in which a pattern body having a linear pattern is placed on a moving stage, and the straightness of the moving stage is measured using the linear pattern.

[0004] Incidentally, since the displacement amount of the wafer chuck changes depending on the installation condition of the prober, for example, even if the displacement amount is confirmed at the time of factory shipment, it is still necessary to confirm it in the user environment which is the installation site of the prober. Accordingly, it is necessary to confirm the displacement amount using the accuracy confirmation wafer even in the user environment, but in this case, labor for preparing the accuracy confirmation wafer is required. Furthermore, since the accuracy confirmation wafer needs to be loaded into the prober, extra man-hours may be required.

[0005] An object of the present disclosure is to provide a wafer chuck displacement amount confirmation method, a wafer chuck, and a prober that can efficiently confirm the displacement amount of a wafer chuck.

[0006] The wafer chuck displacement confirmation method according to this disclosure includes a movement step of moving a wafer chuck having a plurality of marks on its upper surface in a first direction, and a displacement measurement step of measuring the amount of displacement of the plurality of marks in a second direction perpendicular to the first direction, relative to a predetermined true value along the first direction.

[0007] The wafer chuck according to this disclosure is a wafer chuck capable of holding a wafer on which a plurality of semiconductor chips are formed, wherein a plurality of marks are provided on the upper surface, and the plurality of marks are formed in such a way that when the wafer chuck is moved along a first direction, it is possible to measure the amount of displacement of the plurality of marks in a second direction perpendicular to the first direction relative to a predetermined true value along the first direction.

[0008] The prober according to this disclosure comprises a wafer chuck, a probe card having probe needles, a card holder for holding the probe card and positioning the probe card opposite the wafer chuck, a relative movement unit for moving the wafer chuck relative to the probe needles, a first camera for photographing a plurality of marks provided on the wafer chuck, and a second camera for aligning the probe needles.

[0009] According to this disclosure, the effect is that the amount of displacement of the wafer chuck can be efficiently confirmed.

[0010] This is a side view showing an example of the appearance of a prober in a wafer test system. This is a perspective view showing an example of the appearance of a prober. This is a perspective view showing the main components including a wafer chuck. This is a top view showing the main components including a wafer chuck. This is a top view showing an example of a wafer chuck according to the first embodiment. This is a schematic diagram showing an example of the main components including a wafer chuck according to the first embodiment. This is a diagram used to explain the displacement measurement process according to the first embodiment. This is a top view showing an example of a wafer chuck according to the second embodiment. This is a top view showing an example of a wafer for accuracy verification according to the second embodiment. This is a diagram used to explain the error measurement process according to the second embodiment. This is a diagram used to explain the error measurement process according to the second embodiment. This is a diagram used to explain the displacement correction process according to the second embodiment. This is a top view showing an example of a wafer chuck according to the third embodiment. This is a top view showing an example of a wafer chuck according to the fourth embodiment. This is a top view showing an example of a wafer chuck according to the fifth embodiment. This is a top view showing an example of a wafer chuck according to the sixth embodiment. This is a graph showing an example of the change in the displacement of a wafer chuck according to the seventh embodiment.

[0011] Hereinafter, an example of an embodiment for carrying out the technology of this disclosure will be described in detail with reference to the drawings. Components and processes that perform the same operation, action, or function are given the same reference numerals throughout the drawings, and redundant explanations may be omitted as appropriate. Each drawing is only a schematic representation to the extent that the technology of this disclosure can be fully understood. Therefore, the technology of this disclosure is not limited to the illustrated examples. Furthermore, in this embodiment, explanations of configurations not directly related to the technology of this disclosure or well-known configurations may be omitted.

[0012] Figure 1A is a side view showing an example of the appearance of the prober 10 included in the wafer test system 1. Figure 1B is a perspective view showing an example of the appearance of the prober 10. The prober 10 is used in the wafer test system 1 to inspect the electrical characteristics of multiple semiconductor chips formed on a wafer W. Multiple semiconductor chips are formed on the wafer W, and multiple electrode pads are formed on each semiconductor chip. The wafer test system 1 comprises the prober 10 and a control device 40.

[0013] As shown in Figures 1A and 1B, the prober 10 comprises a level pad 11, a base 12, a Y stage 13, a Y movement unit 14, an X stage 15, an X movement unit 16, a Zθ stage 17, a Zθ movement unit 18, a wafer chuck 20, a support column 23, a head stage 24, a card holder 25, a probe card 26, a wafer alignment camera 29, an upper and lower stage 30, a needle alignment camera 31, and a cleaning plate 32. Note that the external configuration of the prober 10 is not limited to the examples shown in Figures 1A and 1B and can be modified as appropriate.

[0014] A Y-stage 13 is supported on the upper surface of the base 12 via a Y-movement unit 14 so as to be movable in the Y-axis direction. The Y-axis direction is an example of a first direction. In addition, four level pads 11 are arranged on the lower surface of the base 12, which are adjustable in the Z-axis direction (vertical direction) of the base 12.

[0015] The Y-movement unit 14 includes, for example, a guide rail provided on the upper surface of the base 12 and parallel to the Y-axis, a slider provided on the lower surface of the Y-stage 13 and engaging with the guide rail, and an actuator such as a motor that moves the Y-stage 13 in the Y-axis direction. This Y-movement unit 14 moves the Y-stage 13 in the Y-axis direction on the base 12.

[0016] The X-stage 15 is supported on the upper surface of the Y-stage 13 via the X-movement unit 16 so as to be movable in the X-axis direction. The X-axis direction is an example of a second direction. The X-axis direction is perpendicular to the Y-axis direction. Here, "perpendicular" means that it is perpendicular including a predetermined error. The X-movement unit 16 includes, for example, a guide rail provided on the upper surface of the Y-stage 13 and parallel to the X-axis, a slider provided on the lower surface of the X-stage 15 and engaging with the guide rail, and an actuator such as a motor that moves the X-stage 15 in the X-axis direction. This X-movement unit 16 moves the X-stage 15 on the Y-stage 13 in the X-axis direction.

[0017] The upper surface of the X-stage 15 is provided with a Zθ stage 17 and upper and lower stages 30. The Zθ stage 17 is provided with a Zθ moving part 18. A wafer chuck 20 is held on the upper surface of the Zθ stage 17 via the Zθ moving part 18.

[0018] The Zθ moving unit 18 includes, for example, a lifting mechanism that moves the Zθ stage 17 in the Z-axis direction (vertical direction) and a rotation mechanism that rotates the Zθ stage 17 around the Z-axis. Therefore, the Zθ moving unit 18 moves the wafer chuck 20, which is held on the upper surface of the Zθ stage 17, in the Z-axis direction and rotates it around the Z-axis.

[0019] A wafer W is held on the upper surface of the wafer chuck 20 by various holding methods such as vacuum suction. The wafer chuck 20 is supported so as to be movable in the XYZ axis direction via the Y stage 13, Y movement unit 14, X stage 15, X movement unit 16, Zθ stage 17, and Zθ movement unit 18 described above, and is also supported so as to be rotatable around the Z axis. This allows the wafer W held in the wafer chuck 20 and the probe needle 35 described later to be moved relative to each other. That is, the Y stage 13 and Y movement unit 14, the X stage 15 and X movement unit 16, and the Zθ stage 17 and Zθ movement unit 18 are examples of relative movement units.

[0020] The support column 23 is provided on the upper surface of the base 12 and supports the head stage 24 above the Y stage 13, X stage 15, and Zθ stage 17 (hereinafter simply referred to as stages 13, 15, and 17). As a result, the head stage 24 is fixed onto the base 12 via the support column 23.

[0021] A card holder 25 is held in the center of the head stage 24. The card holder 25 has a holding hole 25a that holds the outer circumference of the probe card 26, and the probe card 26 is held in this holding hole 25a. As a result, the probe card 26 is held in a position facing the wafer W via the head stage 24 and the card holder 25.

[0022] The probe card 26 has probe needles 35 arranged according to the arrangement of electrode pads on the semiconductor chip to be tested. These card holders 25 and probe cards 26 are replaced depending on the type of semiconductor chip.

[0023] The probe card 26 is provided with connection terminals (not shown) electrically connected to the probe needles 35, and a tester (not shown) is connected to these connection terminals. The tester supplies various test signals to the electrode pads of the semiconductor chip via the connection terminals of the probe card 26 and the probe needles 35, and also receives and analyzes the signals output from the electrode pads to test whether the semiconductor chip is functioning correctly. Note that the configuration of the tester and the test method are known technologies, so a detailed explanation is omitted.

[0024] The wafer alignment camera 29 is an example of a first camera and photographs the semiconductor chips on the wafer W held in the wafer chuck 20. Based on the image captured by this wafer alignment camera 29, the position of the electrode pads of the semiconductor chip to be inspected can be detected. The installation position and structure of the wafer alignment camera 29 are not particularly limited, but for example, it may be installed on the head stage 24.

[0025] The upper and lower stages 30 are equipped with a needle alignment camera 31 and a cleaning plate 32 at positions substantially opposite to the head stage 24, etc. The upper and lower stages 30 also have a lifting mechanism (not shown) that is movable in the Z-axis direction, allowing adjustment of the Z-axis position of the needle alignment camera 31 and the cleaning plate 32. The needle alignment camera 31 and the cleaning plate 32 are supported so as to be movable in the XYZ axes via the Y-stage 13 and Y-movement unit 14, the X-stage 15 and X-movement unit 16, and the upper and lower stages 30. This allows relative movement between the needle alignment camera 31 and the cleaning plate 32 and the probe needle 35. The needle alignment camera 31 may also be located on the Zθ-stage 17. In this case, the upper and lower stages 30 and the cleaning plate 32 may be omitted.

[0026] The needle alignment camera 31 is an example of a second camera and photographs the probe needle 35 of the probe card 26. Based on the image of the probe needle 35 captured by this needle alignment camera 31, the position of the probe needle 35 can be detected. Specifically, the XY coordinates of the tip position of the probe needle 35 are detected from the position coordinates of the needle alignment camera 31, and the Z coordinate of the tip position of the probe needle 35 is detected from the focal point position of the needle alignment camera 31.

[0027] When inspecting semiconductor chips on wafer W with the prober 10 configured as described above, each time the probe card 26 is replaced, or each time a predetermined number of semiconductor chips are inspected, the stages 13, 15, and 17 are driven to move the needle alignment camera 31 relative to the position where the probe needle 35 will be photographed, and then the probe needle 35 is photographed by the needle alignment camera 31. Based on the image captured by the needle alignment camera 31, the tip position of the probe needle 35 is detected.

[0028] Furthermore, with the wafer W to be inspected held in the wafer chuck 20, each stage 13, 15, and 17 is driven to move the wafer alignment camera 29 relative to the shooting position of the wafer W, and then the semiconductor chip of the wafer W is photographed with the wafer alignment camera 29. Based on the image taken by the wafer alignment camera 29, the position of the electrode pads of the semiconductor chip to be inspected is detected.

[0029] Then, stages 13, 15, and 17 are driven to electrically contact the probe needle 35 with the electrode pad of the semiconductor chip to be inspected first. In this state, the tester performs inspection on the semiconductor chip to be inspected first. The remaining semiconductor chips to be inspected are then inspected in the same manner. Note that the specific inspection method for semiconductor chips is publicly known, so a detailed explanation is omitted here.

[0030] The control device 40 is a controller that controls various parts of the prober 10. The control device 40 may be built into the main body of the prober 10, or it may be provided separately from the prober body. The control device 40 is composed of, for example, a computing device such as a personal computer, and includes a computing circuit composed of various processors and memory. Various types of processors include CPUs (Central Processing Units), GPUs (Graphics Processing Units), ASICs (Application Specific Integrated Circuits), and programmable logic devices (e.g., SPLDs (Simple Programmable Logic Devices), CPLDs (Complex Programmable Logic Devices), and FPGAs (Field Programmable Gate Arrays)). The various functions of the control device 40 may be implemented by a single processor, or by multiple processors of the same or different types. Furthermore, the control device 40 is connected to a wafer alignment camera 29 and a needle alignment camera 31, etc., via various communication interfaces (not shown).

[0031] Figure 2A is a perspective view showing the main components including the wafer chuck 20. Figure 2B is a top view showing the main components including the wafer chuck 20. Note that in Figures 2A and 2B, the upper and lower stages 30 and the cleaning plate 32 are omitted from the illustration, and for the sake of explanation, the four level pads 11 are shown as level pads 11A, 11B, 11C, and 11D.

[0032] As shown in Figure 2B, when the wafer chuck 20 is moved in the Y-axis direction, the wafer chuck 20 is displaced by a displacement amount ΔX in the X-axis direction depending on the installation state of the prober 10. For example, if the level pad 11A is relatively low, or if the level pad 11B is relatively high, when the wafer chuck 20 is moved in the Y-axis direction, the movement trajectory shown by the solid line is as follows, and it is displaced by a displacement amount ΔX in the negative X-axis direction. The displacement amount ΔX is defined as the amount by which the wafer chuck 20 is displaced in the X-axis direction relative to a predetermined true value along the Y-axis direction. The true value (i.e., the reference) is defined as the position of the center of the wafer chuck 20 in the X-axis direction when the prober 10 is assumed to be installed horizontally.

[0033] In order to adjust the displacement amount ΔX of the wafer chuck 20, the above-mentioned accuracy verification wafer may be placed on the wafer chuck 20 for adjustment. However, as mentioned above, the displacement amount ΔX of the wafer chuck 20 changes depending on the installation status of the prober 10. For example, even if the displacement amount ΔX is checked at the time of factory shipment, it is necessary to check it in the user environment where the prober 10 is installed. Therefore, it is necessary to check the displacement amount ΔX using the accuracy verification wafer in the user environment as well, but in this case, the user has to take extra steps such as holding the accuracy verification wafer. Furthermore, adjustments are required to load the accuracy verification wafer onto the prober 10, which adds extra work.

[0034] Therefore, in this embodiment, the displacement amount ΔX is confirmed using a wafer chuck 20 with multiple marks on its upper surface. This eliminates the need to use a wafer for accuracy confirmation in the user environment, eliminates the need to make adjustments to load the wafer for accuracy confirmation onto the prober 10, and allows for efficient confirmation of the displacement amount ΔX of the wafer chuck 20.

[0035] [First Embodiment] Figure 3 is a top view showing an example of a wafer chuck 20A according to the first embodiment. The wafer chuck 20A according to this embodiment has a plurality of marks 50 on its top surface. The plurality of marks 50 are formed to enable measurement of the displacement amount ΔX of the plurality of marks 50 in the X-axis direction relative to a predetermined true value along the Y-axis direction when the wafer chuck 20 is moved along the Y-axis direction. Specifically, the plurality of marks 50 include a first mark 50A, a second mark 50B, and a third mark 50C. The first mark 50A is provided at the center of the wafer chuck 20A, and the first mark 50A, the second mark 50B, and the third mark 50C are aligned along the Y-axis direction, which is the direction in which the wafer chuck 20A moves. These first marks 50A, the second mark 50B, and the third mark 50C are processed on the wafer chuck 20A by, for example, cutting, laser marking, etc.

[0036] Furthermore, there may be two or more marks 50, but they are not limited to three. Also, the first mark 50A, the second mark 50B, and the third mark 50C may be, for example, a plus sign, but they are not limited to plus signs, and marks of various shapes can be used. In addition, the first mark 50A, the second mark 50B, and the third mark 50C are arranged at regular intervals, but they do not necessarily have to be at regular intervals.

[0037] Figure 4 is a schematic diagram showing an example of the main components including the wafer chuck 20A according to the first embodiment. As shown in Figure 4, a plurality of marks 50 (see Figure 3) provided on the wafer chuck 20A are positioned using a wafer alignment camera 29.

[0038] Figure 5 is a diagram illustrating the displacement measurement process according to the first embodiment. In this embodiment, we will describe the case where there is no positional error (e.g., machining error) between the first mark 50A, the second mark 50B, and the third mark 50C, and where these marks are arranged in a straight line.

[0039] First, in step S101 of Figure 5, the control device 40 moves the wafer chuck 20A in the Y-axis direction (movement step).

[0040] In step S102, the control device 40 measures the displacement amount ΔX of the first mark 50A, the second mark 50B, and the third mark 50C in the X-axis direction relative to a predetermined true value along the Y-axis direction, based on the image captured by the wafer alignment camera 29 (displacement amount measurement step).

[0041] The inspector can determine that no adjustment of the level pad 11 is necessary if the displacement ΔX is, for example, zero, and adjust the level pad 11 so that the displacement ΔX becomes zero if the displacement ΔX is not zero. For example, if the displacements of the first mark 50A, the second mark 50B, and the third mark 50C are approximately the same, the displacement in the X-axis direction should be adjusted. Also, with respect to the center of the wafer chuck 20A, if the displacement of the third mark 50C on the front side is greater than the displacement of the second mark 50B on the back side, or if the displacement of the third mark 50C on the front side is less than the displacement of the second mark 50B on the back side, the displacements in the X-axis and Y-axis directions should be adjusted. Furthermore, the control device 40 may determine whether the displacement ΔX is within a threshold, and if it determines that the displacement ΔX is within the threshold, it may output a message indicating that no adjustment of the level pad 11 is necessary, and if it determines that the displacement ΔX exceeds the threshold, it may output a message prompting adjustment of the level pad 11.

[0042] According to this embodiment, since there is no need to use a wafer for accuracy verification in the user environment, there is no need to make adjustments to the prober for loading an accuracy verification wafer, and the amount of displacement of the wafer chuck can be efficiently confirmed.

[0043] Furthermore, by arranging three marks in a linear manner, it is possible to measure the amount of displacement on the near side and the far side with the center of the wafer chuck as a reference, which makes it easy to grasp the displacement tendency of the wafer chuck.

[0044] [Second Embodiment] In the above first embodiment, a description has been given of a state where there is no error (for example, processing error) in the positions of the plurality of marks at all. In the second embodiment, a description will be given of a state where there is an error (for example, processing error) in the positions of the plurality of marks. Hereinafter, the amount of position error of the plurality of marks is referred to as "mark position error amount".

[0045] FIG. 6 is a top view illustrating an example of a wafer chuck 20B according to the second embodiment. The wafer chuck 20B according to the present embodiment is provided with a plurality of marks 51 on an upper surface thereof. Specifically, the plurality of marks 51 include a first mark 51A, a second mark 51B, a third mark 51C, a fourth mark 51D, and a fifth mark 51E. The first mark 51A is provided at the center of the wafer chuck 20B, the first mark 51A, the second mark 51B, and the third mark 51C are aligned along the Y-axis direction, and the first mark 51A, the fourth mark 51D, and the fifth mark 51E are aligned along the X-axis direction. These first mark 51A, second mark 51B, third mark 51C, fourth mark 51D, and fifth mark 51E are, for example, plus marks, but are not limited to plus marks.

[0046] FIG. 7 is a top view illustrating an example of an accuracy verification wafer 100 according to the second embodiment. The accuracy verification wafer 100 according to the present embodiment is provided with a plurality of marks 101 on an upper surface thereof. Specifically, the plurality of marks 101 include a first mark 101A, a second mark 101B, a third mark 101C, a fourth mark 101D, and a fifth mark 101E. The first mark 101A is provided at the center of the accuracy verification wafer 100, the first mark 101A, the second mark 101B, and the third mark 101C are aligned along the Y-axis direction, and the first mark 101A, the fourth mark 101D, and the fifth mark 101E are aligned along the X-axis direction.

[0047] A plurality of marks 51 provided on the wafer chuck 20B may have positional errors. Therefore, in the present embodiment, a mark position error amount is obtained using an accuracy confirmation wafer 100, which is a wafer for confirming the displacement amount of the wafer chuck 20B. That is, the control device 40 according to the present embodiment measures a mark position error amount using the accuracy confirmation wafer 100 placed on the wafer chuck 20B (error amount measurement step), and calculates a corrected displacement amount, which is a displacement amount obtained by correcting the displacement amounts of the plurality of marks 51 provided on the wafer chuck 20B with the mark position error amount (displacement amount correction step).

[0048] FIGS. 8 and 9 are diagrams for explaining an error amount measurement step according to a second embodiment. First, in step S111 of FIG. 8, the control device 40 aligns the angle of the accuracy confirmation wafer 100 parallel to the X-axis (angle adjustment step) using marks arranged in the X-axis direction of the accuracy confirmation wafer 100 placed on the wafer chuck 20B.

[0049] In step S112, the control device 40 moves the accuracy confirmation wafer 100 in the Y-axis direction (movement step).

[0050] In step S113, the control device 40 measures a displacement amount ΔX1 by which a mark arranged in the Y-axis direction of the accuracy confirmation wafer 100 is displaced in the X-axis direction with respect to a predetermined true value along the Y-axis direction, based on a captured image captured by a wafer alignment camera 29 (displacement amount measurement step).

[0051] Then, in step S114 of FIG. 9, the control device 40 aligns the angle of the wafer chuck 20B parallel to the X-axis (angle adjustment step) using marks arranged in the X-axis direction of the wafer chuck 20B.

[0052] In step S115, the control device 40 moves the wafer chuck 20B in the Y-axis direction (movement step).

[0053] In step S116, the control device 40 measures the displacement amount ΔX2 of the marks positioned in the Y-axis direction of the wafer chuck 20B in the X-axis direction relative to a predetermined true value in the Y-axis direction, based on the image captured by the wafer alignment camera 29 (displacement amount measurement step).

[0054] In step S117, the control device 40 calculates the difference between the displacement amount ΔX1 measured in step S113 and the displacement amount ΔX2 measured in step S116 as the mark position error amount E (E = ΔX2 - ΔX1) (error amount measurement step). The mark position error amount E is stored in the memory of the control device 40. Here, the mark position error amount E only needs to be calculated and stored in the control device 40, for example, at the time of factory shipment, and there is no need to perform the error amount measurement step in the user environment. In other words, after calculating the mark position error amount E, the displacement amounts obtained by actually measuring the multiple marks 51 of the wafer chuck 20B can be corrected with the mark position error amount E.

[0055] Figure 10 is a diagram illustrating the displacement correction process according to the second embodiment. First, in step S121 of Figure 10, the control device 40 adjusts the angle of the wafer chuck 20B to be parallel to the X-axis using marks positioned in the X-axis direction of the wafer chuck 20B (angle adjustment process).

[0056] In step S122, the control device 40 moves the wafer chuck 20B in the Y-axis direction (movement step).

[0057] In step S123, the control device 40 measures the displacement amount ΔX3 of the marks positioned in the Y-axis direction of the wafer chuck 20B in the X-axis direction relative to a predetermined true value along the Y-axis direction, based on the image captured by the wafer alignment camera 29 (displacement amount measurement step).

[0058] In step S124, the control device 40 calculates a corrected displacement amount ΔX4 (ΔX4 = ΔX3 - E), which is the displacement amount obtained by correcting the displacement amount ΔX3 of the wafer chuck 20B by the mark position error amount E (displacement amount correction step).

[0059] According to this embodiment, even if there are errors in the positions of multiple marks, the amount of displacement can be accurately confirmed.

[0060] Furthermore, by arranging the five marks in a plus sign shape, it is possible to measure not only the displacement of the wafer chuck but also the angle of the wafer chuck with respect to the X-axis direction.

[0061] In this embodiment, an example was described in which five marks are arranged in a plus sign shape on the wafer chuck. However, the arrangement of the marks on the wafer chuck and the marks on the wafer used for accuracy verification may be the same or different, and the invention is not limited to this arrangement example.

[0062] [Third Embodiment] In the third embodiment, a configuration in which no mark is placed in the center of the wafer chuck will be described.

[0063] Figure 11 is a top view showing an example of a wafer chuck 20C according to a third embodiment. The wafer chuck 20C according to this embodiment has a plurality of marks 52 on its top surface. Specifically, the plurality of marks 52 include a first mark 52A, a second mark 52B, a third mark 52C, and a fourth mark 52D. The centers P of the first mark 52A, the second mark 52B, and the wafer chuck 20C are aligned along the Y-axis, and the centers P of the third mark 52C, the fourth mark 52D, and the wafer chuck 20C are aligned along the X-axis. The first mark 52A, the second mark 52B, the third mark 52C, and the fourth mark 52D are, for example, circular marks.

[0064] According to this embodiment, the displacement of the wafer chuck can be measured without having to mark the center of the wafer chuck.

[0065] [Fourth Embodiment] In the second embodiment described above, a configuration was described in which the wafer for accuracy verification is loaded in a position that hides the mark on the wafer chuck. In the fourth embodiment, a configuration will be described in which the wafer for accuracy verification is loaded in a position that does not hide the mark on the wafer chuck.

[0066] Figure 12 is a top view showing an example of a wafer chuck 20D according to a fourth embodiment. The wafer chuck 20D according to this embodiment has a plurality of marks 53 on its top surface. Specifically, the plurality of marks 53 include a first mark 53A, a second mark 53B, a third mark 53C, and a fourth mark 53D. The first mark 53A, the second mark 53B, and the center P of the wafer chuck 20D are aligned along the Y-axis, and the third mark 53C, the fourth mark 53D, and the center P of the wafer chuck 20D are aligned along the X-axis. The first mark 53A, the second mark 53B, the third mark 53C, and the fourth mark 53D are, for example, plus signs.

[0067] As shown in Figure 12, the diameter of the wafer chuck 20D is larger than the diameter of the accuracy verification wafer 100. The first mark 53A, the second mark 53B, the third mark 53C, and the fourth mark 53D are positioned so as not to be obscured by the accuracy verification wafer 100 when it is placed on the wafer chuck 20D.

[0068] Here, if the accuracy verification wafer 100 is placed in a position where multiple marks on the wafer chuck 20D are hidden, the multiple marks on the accuracy verification wafer 100 and the multiple marks on the wafer chuck 20D will be close together, thus improving the accuracy of the measurement. On the other hand, in this case, efficiency decreases because, after measuring the displacement amount on the accuracy verification wafer 100, it is necessary to unload the accuracy verification wafer 100 in order to measure the displacement amount on the wafer chuck 20D. In contrast, as shown in Figure 12, by placing the accuracy verification wafer 100 in a position where the multiple marks 53 on the wafer chuck 20D are not hidden by the accuracy verification wafer 100, it becomes unnecessary to unload the accuracy verification wafer 100, thus improving efficiency.

[0069] According to this embodiment, since the multiple marks provided on the wafer chuck are not obscured by the wafer used for accuracy verification, there is no need to unload the wafer used for accuracy verification.

[0070] [Fifth Embodiment] In the fifth embodiment, a configuration is described in which multiple suction grooves of the wafer chuck are used as multiple marks.

[0071] Figure 13 is a top view showing an example of a wafer chuck 20E according to the fifth embodiment. The wafer chuck 20E according to this embodiment has a plurality of marks 54 on its top surface. Specifically, the plurality of marks 54 are the first suction groove 54A, second suction groove 54B, third suction groove 54C, and fourth suction groove 54D of the wafer chuck 20E. The centers of the first suction groove 54A, the second suction groove 54B, and the wafer chuck 20E are aligned along the Y-axis, and the centers of the third suction groove 54C, the fourth suction groove 54D, and the wafer chuck 20E are aligned along the X-axis. These first suction groove 54A, second suction groove 54B, third suction groove 54C, and fourth suction groove 54D are grooves that the wafer chuck 20E has in advance and are not processed afterward. As shown in Figure 13, the mark shape is not particularly limited, so the suction grooves that the wafer chuck 20E has in advance may be used.

[0072] According to this embodiment, since it is not necessary to process multiple marks on the wafer chuck, the processing cost of the wafer chuck can be reduced.

[0073] [Sixth Embodiment] In the sixth embodiment, a configuration in which a needle alignment camera is used as one of a plurality of marks will be described.

[0074] Figure 14 is a top view showing an example of a wafer chuck 20F according to the sixth embodiment. The wafer chuck 20F according to this embodiment has a plurality of marks 55 on its top surface. Specifically, the plurality of marks 55 include a first mark 55A, a second mark 55B, and a third mark 55C. The first mark 55A is located at the center of the wafer chuck 20F, and the first mark 55A, the second mark 55B, and the third mark 55C are aligned along the Y-axis direction, which is the direction in which the wafer chuck 20F moves, and the second mark 55B or the third mark 55C is a beam output from the needle alignment camera 31.

[0075] The prober 10 is equipped with a needle alignment camera 31 to detect the position of the probe needle 35. The needle alignment camera 31 can output a beam to detect the relative position of the probe needle 35. Therefore, by making the second mark 55B or the third mark 55C the beam output from the needle alignment camera 31, one of the multiple marks 55 is eliminated. As the mark position error amount E was calculated in the second embodiment described above, it is desirable to determine the mark position error amount E' using the accuracy verification wafer 100. In other words, the control device 40 according to this embodiment measures the mark position error amount E' using the accuracy verification wafer 100 placed on the wafer chuck 20F, calculates a corrected displacement amount which is the displacement amount obtained by correcting the displacement amount of the multiple marks 55, including the beam of the needle alignment camera 31, provided on the wafer chuck 20F by the mark position error amount E', and stores it in the memory of the control device 40.

[0076] According to this embodiment, by making one of the three marks a beam output from a needle alignment camera, the number of marks to be processed can be reduced.

[0077] [Seventh Embodiment] In the seventh embodiment, a configuration is described in which the amount of displacement of the wafer chuck is checked periodically or at any arbitrary time.

[0078] Figure 15 is a graph showing an example of the change in the amount of displacement of the wafer chuck 20A according to the seventh embodiment. In Figure 15, the vertical axis represents the amount of displacement, and the horizontal axis represents time. The control device 40 according to this embodiment periodically or at arbitrary timings checks the amount of displacement ΔX of the wafer chuck 20A, and issues a notification prompting maintenance to be performed when the amount of displacement ΔX exceeds a threshold (notification step).

[0079] It is conceivable that the displacement amount ΔX will gradually increase due to the aging deterioration of the drive part of the prober 10. Therefore, by photographing the positions of the multiple marks 50 provided on the wafer chuck 20A with the wafer alignment camera 29 at regular intervals or at arbitrary times, measurement accuracy can be maintained and maintenance timing can be predicted. As shown in Figure 15, when the displacement amount ΔX exceeds a threshold, a notification prompting maintenance is issued to prevent accuracy abnormalities.

[0080] According to this embodiment, maintenance can be performed periodically or at any time.

[0081] As described above, according to each embodiment, there is no need to use a wafer for accuracy verification in the user environment, and therefore there is no need to make adjustments to load the wafer for accuracy verification onto the prober, and the amount of displacement of the wafer chuck can be efficiently confirmed.

[0082] This disclosure is not limited to the embodiments described above, and various modifications and applications are possible without departing from the gist of this disclosure.

[0083] The disclosure of Japanese Patent Application No. 2025-048967, filed on 24 March 2025, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference.

Claims

1. A wafer chuck displacement confirmation method comprising: a movement step of moving a wafer chuck having multiple marks on its upper surface in a first direction; and a displacement measurement step of measuring the amount of displacement of the multiple marks in a second direction perpendicular to the first direction relative to a predetermined true value along the first direction.

2. A wafer chuck displacement confirmation method according to claim 1, further comprising: an error amount measurement step of measuring the error amount of the positions of the plurality of marks using the accuracy confirmation wafer which is a wafer for confirming the displacement amount of the wafer chuck, and a displacement amount correction step of calculating a corrected displacement amount which is the displacement amount obtained by correcting the displacement amount by the error amount.

3. The wafer chuck displacement amount confirmation method according to claim 1 or 2, further comprising a notification step of periodically or at arbitrary times checking the amount of displacement of the wafer chuck and issuing a notification prompting maintenance to be performed if the amount of displacement exceeds a threshold.

4. A wafer chuck capable of holding a wafer on which multiple semiconductor chips are formed, wherein a plurality of marks are provided on the upper surface, and the plurality of marks are formed in such a way that when the wafer chuck is moved along a first direction, it is possible to measure the amount of displacement of the plurality of marks in a second direction perpendicular to the first direction relative to a predetermined true value along the first direction.

5. The wafer chuck according to claim 4, wherein the plurality of marks include a first mark, a second mark, and a third mark, the first mark being located at the center of the wafer chuck, and the first mark, the second mark, and the third mark being aligned along a first direction which is the direction in which the wafer chuck moves.

6. The wafer chuck according to claim 4, wherein the plurality of marks include a first mark, a second mark, a third mark, a fourth mark, and a fifth mark, the first mark being located at the center of the wafer chuck, the first mark, the second mark, and the third mark being aligned along a first direction, and the first mark, the fourth mark, and the fifth mark being aligned along a second direction perpendicular to the first direction.

7. The wafer chuck according to claim 4, wherein the plurality of marks include a first mark, a second mark, a third mark, and a fourth mark, the first mark, the second mark, and the center of the wafer chuck are aligned along the first direction, and the third mark, the fourth mark, and the center of the wafer chuck are aligned along a second direction perpendicular to the first direction.

8. The wafer chuck according to claim 7, wherein the diameter of the wafer chuck is greater than the diameter of a precision verification wafer, which is a wafer used to check the displacement of the wafer chuck, and the first mark, the second mark, the third mark, and the fourth mark are positioned so as not to be obscured by the precision verification wafer when the precision verification wafer is placed on the wafer chuck.

9. The wafer chuck according to claim 4, wherein the plurality of marks are a first suction groove, a second suction groove, a third suction groove, and a fourth suction groove of the wafer chuck, the first suction groove, the second suction groove, and the center of the wafer chuck are aligned along the first direction, and the third suction groove, the fourth suction groove, and the center of the wafer chuck are aligned along a second direction perpendicular to the first direction.

10. The wafer chuck according to claim 4, wherein the plurality of marks include a first mark, a second mark, and a third mark, the first mark being located at the center of the wafer chuck, the first mark, the second mark, and the third mark being aligned along a first direction which is the direction in which the wafer chuck moves, and the second mark or the third mark being a beam output from a camera used for aligning a probe needle.

11. A prober comprising: a wafer chuck according to any one of claims 4 to 10; a probe card having probe needles; a card holder for holding the probe card and positioning the probe card opposite the wafer chuck; a relative movement unit for moving the wafer chuck relative to the probe needles; a first camera for photographing a plurality of marks provided on the wafer chuck; and a second camera for aligning the probe needles.

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