Detector and probe inspection method

Abstract

A probe (100) for performing an electrical test on a wafer, comprising: a wafer chuck (20) having a holding surface that holds a wafer (W); a probe card (25) having a plurality of probes (26) on a surface facing the holding surface; an alignment device that positions the wafer chuck with respect to the probe card; and a control device including a memory, a processor, and a program stored in the memory and configured to be executable by the processor, the program including a command to switch position control of the alignment device from full close control to semi-close control at a first timing related to the start of the electrical test, with which the probe can perform alignment with high accuracy even in the case of high voltage measurement.

Description

Technical Field

[0001] This disclosure relates to detector and probe inspection methods for performing electrical tests on wafers. Background Technology

[0002] A detector is known as a device for verifying the operation of a semiconductor chip formed on a wafer. This verification of operation is an electrical test known as wafer level check. Specifically, the electrode pads of the semiconductor chip are connected to a test head via probes, power and test signals are supplied from the test head, and the signal output by the semiconductor chip is measured using the test head.

[0003] In wafer level inspection, multiple probes need to make high-precision contact with the electrode pads of the semiconductor chip. In other words, high-precision alignment (positioning) of the probes (probe cards) with the electrode pads of the semiconductor chip is required.

[0004] As such a technology, Patent Document 1 discloses a detector and probe alignment method capable of high-precision alignment.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2022-175805 Summary of the Invention

[0006] The problem the invention aims to solve In recent years, the applications of power semiconductors have been expanding. Power semiconductors are used in power converters such as inverters and converters, enabling operation at higher voltages, higher currents, and higher frequencies. In particular, the demand is growing with the increasing popularity of electric vehicles such as EVs (electric vehicles) and PHEVs (plug-in hybrid electric vehicles).

[0007] To conduct electrical tests on such semiconductor chips, the requirements for stable testing of the detector at higher voltages have increased.

[0008] The inventors have discovered that during high-voltage measurements using a detector, sparks are generated within the device, particularly inside the wafer, which can affect the operation of the wafer alignment mechanism. Specifically, the sparks are found to appear as noise in the output signal of the alignment mechanism's position detection unit (e.g., a linear scale). This noise sometimes exceeds the alarm threshold of the position detection unit. In most cases, noise exceeding the alarm threshold causes the alignment mechanism and the detector itself to stop operating.

[0009] Figure 7 This is a diagram illustrating an example of the output signal of a linear scale (position detection unit) in an existing detector. The horizontal axis 50 represents time, and the vertical axis 51 represents the magnitude of the output signal. Figure 7The diagram illustrates the impact on the output signal 52 of the linear scale when a spark occurs. Specifically, when a spark is generated within the device, a large-amplitude noise 53 is produced in the output signal 52. When this noise exceeds the alarm thresholds (indicated by reference numeral 56) of the upper limit 54 and / or lower limit 55, the detector operation typically stops. As long as the detector operation ceases, the inspection efficiency of the wafer W is significantly reduced.

[0010] The objective of this disclosure is to address at least one problem with the prior art described above. One specific objective is to provide a method for inspecting detectors and probes that enables high-precision alignment even during high-voltage measurements.

[0011] Solution for solving the problem One embodiment of the detector disclosed herein is a detector for performing electrical tests on a wafer, comprising: a wafer chuck having a holding surface for holding the wafer; a probe card having a plurality of probes on a surface facing the holding surface; an alignment device for positioning the wafer chuck relative to the probe card; and a control device including a memory, a processor, and a program stored in the memory and configured to be executable by the processor, the program including a command, at a first timing related to the start of the electrical test, to switch the position control of the alignment device from fully closed control to half-closed control.

[0012] One embodiment of the probe inspection method disclosed herein is a probe inspection method comprising: positioning a wafer chuck holding a wafer on a holding surface relative to a probe chuck having a plurality of probes on a surface facing the holding surface using an alignment device; performing an electrical test on the wafer using the probes that have contacted the wafer; and switching the position control of the alignment device from fully closed control to partially closed control at a first timing associated with the start of the electrical test.

[0013] Invention Effects By employing this disclosure, at least one problem of the prior art can be solved. One specific effect is that it provides a detector and probe inspection method that can achieve high-precision alignment even when performing high-voltage measurements. Attached Figure Description

[0014] Figure 1 This is a block diagram illustrating the system structure of the detector according to an embodiment.

[0015] Figure 2 This is a diagram illustrating the function of the control switching unit during fully closed control.

[0016] Figure 3 This is a diagram illustrating the function of the control switching unit during semi-closed control.

[0017] Figure 4 This is a flowchart illustrating the sequence of electrical tests (wafer level checks) using detectors.

[0018] Figure 5 This is another flowchart illustrating the sequence of electrical tests (wafer level checks) using a detector.

[0019] Figure 6 This is another flowchart illustrating the sequence of electrical tests (wafer level checks) using a detector.

[0020] Figure 7 This is a diagram illustrating an example of the output signal of a linear scale (position detection unit) in an existing detector. Detailed Implementation

[0021] A first embodiment of the detector disclosed herein is a detector for performing electrical tests on a wafer, comprising: a wafer chuck having a holding surface for holding the wafer; a probe card having a plurality of probes on a surface facing the holding surface; an alignment device for positioning the wafer chuck relative to the probe card; and a control device including a memory, a processor, and a program stored in the memory and configured to be executable by the processor, the program including a command to switch the position control of the alignment device from fully closed control to half-closed control at a first timing related to the start of the electrical test.

[0022] Using the aforementioned detector, at the first timing related to the start of the electrical test, the alignment device switches from fully closed control to semi-closed control.

[0023] During wafer level checks (electrical tests), the alignment device is controlled by a semi-closed control that does not use the output signal of the position detection unit. Therefore, even during tests with applied high voltage, the alignment device and detector can be prevented from stopping due to noise mixed in with the output signal of the position detection unit.

[0024] In addition, since the first timing related to the start of the electrical test is switched from fully closed control, in other words, since positioning is performed by fully closed control up to the first timing, the positioning accuracy is also improved.

[0025] Generally speaking, the positioning accuracy of semi-closed control is worse than that of fully closed control.

[0026] However, in the aforementioned detector, since the semi-closed control is only switched according to the first timing, the positioning accuracy up to this point is relatively high. Furthermore, wafer level checks (electrical tests) are typically performed with the electrode pads of the semiconductor chip on the wafer in contact with the probes of the probe card. That is, when the electrical test begins, the alignment device is primarily required to stop the wafer at a specified position. Therefore, the positioning accuracy required during the electrical test is not high compared to the positioning before the electrical test begins.

[0027] In other words, while the aforementioned detector allows for partial closed-loop control in some areas, when viewed as a whole during the wafer level inspection process, it enables more stable implementation, even for electrical tests requiring high voltage, compared to existing technologies. Furthermore, the positioning accuracy is also higher.

[0028] The second embodiment of the detector disclosed herein is based on the first embodiment, wherein the alignment device comprises: a position detection unit that detects the position of the wafer chuck; a drive unit that drives the wafer chuck; and a feedback sensor disposed in the drive unit.

[0029] The alignment device includes a position detection unit and a feedback sensor. Therefore, before and after the first timing, the position control of the wafer chuck is switched from fully closed control based on the output signal of the position detection unit to semi-closed control based on the output signal of the feedback sensor. The output signal of the feedback sensor is also less prone to generating significant noise when a high voltage is applied, resulting in more stable detector operation.

[0030] The third embodiment of the detector disclosed herein is based on the first or second embodiment, wherein the first timing is prior to the application of the measuring voltage for the electrical test.

[0031] Setting the first timing before (specifically, immediately before) the measurement voltage used for electrical testing means positioning is performed via fully closed control until the measurement voltage is applied. Using this detector further improves positioning accuracy and makes the detector's operation more stable.

[0032] The fourth embodiment of the detector disclosed herein, based on the first or second embodiment, includes a test head that supplies test signals to the wafer through the plurality of probes, wherein the first timing occurs immediately after the control device receives a measurement start signal from the test head.

[0033] Setting the first timing immediately after receiving the signal to begin measurement means that positioning based on fully closed control is performed until a high voltage, which is the cause of noise in the output signal of the position detection device, is applied immediately before this point. Using the above-described detector, positioning accuracy is further improved, and the detector's operation is also more stable.

[0034] The fifth embodiment of the detector disclosed herein is based on the first or second embodiment, wherein the first timing is after the wafer chuck is positioned at a predetermined position for initiating the electrical test.

[0035] By setting the first timing after positioning (typically immediately following), the timing for switching to semi-closed control can be determined solely through the control sequence of the alignment device, without waiting for signals related to the start of the electrical test. Therefore, detector control becomes much easier. Of course, switching to semi-closed control can also be initiated based on a test start signal provided by the test head.

[0036] The sixth embodiment of the detector disclosed herein, based on the first or second embodiment, wherein the alignment device is configured to move the wafer chuck in a Z-axis direction opposite to the probe card and in an XY-axis direction substantially parallel to the probe card, wherein the first timing is prior to the upward movement of the wafer chuck toward the probe card in the Z-axis direction.

[0037] Multiple semiconductor chips are formed on a wafer held in a wafer chuck. Electrical testing is performed by bringing probes into contact with the electrode pads of the multiple semiconductor chips, one by one. For this purpose, multiple probes are configured on a probe card.

[0038] Therefore, precise positioning of the wafer and probes is essential for the correct implementation of wafer level checks. In particular, higher positioning accuracy is required in the XY axis direction to align multiple probes and electrode pads.

[0039] On the other hand, Z-axis position control is typically performed to bring the probe, which acts as an elastomer, into contact with the electrode pads. Compared to the XY axes, Z-axis position control sometimes requires slightly lower precision. Therefore, even when switching to semi-closed control before (typically immediately before) Z-axis position control, the impact on measurement accuracy can be minimized as a whole for the detector.

[0040] The seventh embodiment of the detector disclosed herein, based on the sixth embodiment, further includes a command to position the alignment device in the XY-axis direction before the electrical test begins and before switching to the semi-closed control.

[0041] In the aforementioned detector, positioning is achieved through fully enclosed control along the X and Y axes. Therefore, superior positioning accuracy can be obtained.

[0042] An eighth embodiment of the detector disclosed herein, based on the first or second embodiment, includes a procedure that includes a command, at a second timing related to the end of the electrical test, to switch the position control of the alignment device from half-closed control to fully-closed control.

[0043] During the electrical test, the position detection unit may generate noise due to the application of high voltage. On the other hand, after the electrical test is completed, since this possibility is almost non-existent, the positioning accuracy is further improved by switching to fully closed control at the second timing.

[0044] The ninth embodiment of the detector disclosed herein is based on the eighth embodiment, wherein the second timing is after the electrical test has ended and before the wafer chuck begins to move.

[0045] As mentioned above, the alignment device in the electrical test is positioned relative to the wafer chuck by stopping in place (at a specified position). Therefore, the impact of semi-closed control on positioning accuracy is minimized. In the detector described above, a fully closed control with higher positioning accuracy is switched to before the wafer chuck begins to move (typically immediately before). Therefore, the overall positioning accuracy and stability of the detector are higher.

[0046] A first embodiment of the probe inspection method disclosed herein is a probe inspection method comprising: positioning a wafer chuck holding a wafer on a holding surface relative to a probe chuck having a plurality of probes on a surface facing the holding surface using an alignment device; performing an electrical test on the wafer using the probes that have contacted the wafer; and switching the position control of the alignment device from fully closed control to partially closed control at a first timing associated with the start of the electrical test.

[0047] Using the probe inspection method described above, at the first timing related to the start of the electrical test, the position control of the alignment device is switched from fully closed control to semi-closed control.

[0048] During wafer level inspection (electrical testing), the alignment device is controlled by a semi-closed control that does not use the output signal of the position detection unit. Therefore, even during high-voltage tests, the alignment device and detector can be prevented from stopping due to noise generated by the position detection unit.

[0049] In addition, since the control switches from fully closed to open at the first timing related to the start of the electrical test, in other words, the positioning accuracy is improved because positioning is performed by fully closed control up to the first timing.

[0050] Figure 1 This is a block diagram illustrating the system structure of the detector according to an embodiment. The detector 100 includes a detector control unit 10, an XY platform 22, a Zθ platform 21, a wafer chuck 20, a probe 26, a probe card 25, and a servo amplifier 30, etc.

[0051] The detector control unit 10 includes a memory and a processor. Typically, the detector control unit 10 is a computer and serves as the control device for the detector 10. The detector control unit 10 executes programs stored in the memory via the processor, issuing instructions to the servo amplifier 30 and the like to control the actions (sequence of actions) of the detector 10.

[0052] The detector control unit 10 includes a communication unit 10-1 and a drive control unit 10-2. These functions are implemented through commands, associated hardware, and associated software contained in a program stored in the memory of the detector control unit 10.

[0053] The communication unit 10-1 performs its functions through hardware such as a communication interface and software such as associated drivers. Based on commands contained in the program of the detector control unit 10, the communication unit 10-1 establishes the connection between the detector control unit 10 and the test head 29, and performs signal transmission and reception, as well as data conversion.

[0054] The drive control unit 10-2 controls the alignment device (XY platform 22 and Zθ platform 21) to adjust the position of the wafer W according to the commands contained in the program of the detector control unit 10. The alignment device is controlled directly by the servo amplifier 30. The servo amplifier 30 operates according to the instructions of the drive control unit 10-2. That is, the servo amplifier 30 constitutes part of the control device.

[0055] The servo amplifier 30 includes a position information acquisition unit 30-1, a control switching unit 30-2, and a motor control unit 30-3. These are all functions of the servo amplifier 30, which will be described in detail later.

[0056] The wafer chuck 20 has a holding surface for holding the wafer W. The relative position of the wafer W held on the holding surface and the probe card 25 is adjusted by the XY platform 22 and the Zθ platform 21. That is, the XY platform 22 and the Zθ platform 21 constitute an alignment device for positioning the wafer chuck 20 relative to the probe card 25.

[0057] It should be noted that the XY platform 22 is responsible for position adjustment along the direction of the wafer W's surface (XY axis direction). The XY axis direction is also approximately parallel to the probe card 25. Additionally, the Zθ platform 21 is responsible for position adjustment in the direction the wafer W's surface faces (Z axis direction) and in the θ axis direction. It should be noted that the θ axis is a rotational axis centered on the Z axis.

[0058] It should be noted that the XY platform 22 includes a servo motor 27 as a drive unit, a linear scale 24 as a position detection unit, and a rotary encoder 28 as a feedback sensor. However, the drive unit, position detection unit, and feedback sensor included in the alignment device are not limited to the above. For example, the drive unit is not particularly limited as long as it can drive the XY platform 22. For example, it can be a stepper motor, a brushless motor, or a vector-controlled variable frequency speed control motor with a sensor. In addition, the position detection unit detects the position of the chip chuck 20 (or the position of the XY platform 22), and there is no particular limitation as long as the output signal can be used for feedback control of the drive unit. For example, if it is a linear scale, it can be optical, magnetic, electrostatic capacitive, or a combination thereof. Other position detection units include laser interferometers. In addition, regarding the feedback sensor, there is no particular limitation on its form as long as it is a device that can measure the rotation angle of the motor that serves as the drive unit. A magnetostrictive displacement sensor can also be used instead of a rotary encoder.

[0059] When the drive unit is a pulse motor, the feedback sensor can be omitted. In this case, the semi-closed control is replaced by position control solely through pulse commands from the servo amplifier 30. Alternatively, the fully closed control can be achieved simply by feeding back the linear scale information from the linear scale 24 to the servo amplifier 30 for position control.

[0060] Furthermore, although the illustration is omitted, the Zθ platform 21, like the XY platform 22, preferably includes a drive unit, a position detection device, and a feedback sensor. The aforementioned hardware components of the Zθ platform 21 can be the same as those of the XY platform 22.

[0061] The probe card 25 has multiple probes 26. Each probe 26 is connected to a terminal of the test head 29. During wafer level inspection, the probes 26 contact the electrode pads of the semiconductor chip formed on the wafer W. The contact position is adjusted by an alignment device.

[0062] As described above, the terminals of the test head 29 are electrically connected to the electrode pads via probe 26.

[0063] Test head 29 provides power and test signals to the electrode pads. Additionally, test head 29 detects the output from the electrode pads. As described above, a wafer level check (electrical test) is performed.

[0064] Next, one method for implementing electrical tests will be explained. Figure 4 This is a flowchart showing the sequence of electrical tests (wafer level checks) using detector 100.

[0065] First, in step S1, the servo amplifier 30 controls the servo motor 27 to position the XY platform 22. The servo amplifier 30 receives instructions from the drive control unit 10-2 to perform the above positioning. When the communication unit 10-1 of the detector control unit 10 receives a signal from the test head 29 indicating the start of the electrical test, the drive control unit 10-2 sends the above instructions.

[0066] Specifically, the XY platform 22 holding the chip W in the chip chuck 20 is positioned by a ball screw 23 driven by a servo motor 27.

[0067] When the ball screw 23 is rotated by the servo motor 27, the XY platform 22 moves to a predetermined position. The position of the XY platform 22 (i.e., the position of the wafer chuck 20) ​​is detected by the linear scale 24 to determine if the movement matches the command. Additionally, the rotation of the servo motor 27 is detected by the rotary encoder 28 to determine if it matches the command. The detected linear scale information 62 and encoder information 61 are input to the position information acquisition unit 30-1 of the servo amplifier 30.

[0068] The position information acquisition unit 30-1 sends the acquired position information to the motor control unit 30-3 via the control switching unit 30-2. The motor control unit 30-3 sends motor command information 64 to the servo motor 27 based on the position information, driving the XY platform 22 to the specified position corresponding to the probe card 25.

[0069] At this time, the position control of the XY platform 22 is performed using fully closed control via linear scale information 62 detected by the linear scale 24. In other words, the positioning of the alignment device in the XY axis direction is performed via fully closed control. Details will be described later. The position information acquisition unit 30-1 sends the linear scale information 62 and encoder information 61 as position information to the control switching unit 30-2. The control switching unit 30-2 sends only the linear scale information 62 as the selected position information 63 to the motor control unit 30-3.

[0070] Next, in step S2, based on the control switching command 60 of the drive control unit 10-2, the control switching unit 30-2 of the servo amplifier 30 switches the positioning of the alignment device to semi-closed control.

[0071] In other words, at the timing of the end of positioning of the alignment device in the XY axis direction that accompanies the start of the electrical test (an example of the first timing), the drive control unit 10-2 sends a control switching command 60 to the control switching unit 30-2.

[0072] It should be noted that the timing of the end of positioning in the XY axis direction can be immediately before the wafer chuck 20 moves upward in the Z axis direction, or immediately after the servo amplifier 30 receives the command for the Zθ platform 21 to rise. It should also be noted that the command for the Zθ platform 21 to rise can be a command received from the drive control unit 10-2 based on the driving status of the alignment device, or a command received from the drive control unit 10-2 based on a higher-level command received from the test head 29.

[0073] When switching to semi-closed control, the control switching unit 30-2 sends encoder information 61 to the motor control unit 30-3 as the selected position information 63.

[0074] This section details an example of a method for switching between fully closed and partially closed control.

[0075] Figure 2 This is an explanatory diagram of the function of the control switching unit 30-2 during fully closed control.

[0076] The control switching unit 30-2 selects any one of the position information obtained by the position information acquisition unit 30-1 as the selected position information 63 and transmits it to the motor control unit 30-3 for feedback control.

[0077] The position information acquisition unit 30-1 acquires encoder information 61 from the rotary encoder 28 and linear scale information 62 from the linear scale 24.

[0078] The control switching unit 30-2 sends the linear scale information 62 as the selected position information 63 to the motor control unit 30-3, thus entering a fully closed control state.

[0079] on the other hand, Figure 3 This is an explanatory diagram illustrating the function of the control switching unit 30-2 during semi-closed control. In this case, the control switching unit 30-2 sends the encoder information 61 as the selected position information 63 to the motor control unit 30-3.

[0080] In this way, semi-closed control and fully closed control can be easily switched.

[0081] Next, in step S3, the servo amplifier 30, receiving the instruction from the drive control unit 10-2, controls the servo motor 27 to raise the Zθ platform 21 for positioning. Specifically, the Zθ platform 21 is used to raise the wafer W held in the wafer chuck 20 in the Z-axis direction, so that the probe 26 contacts the electrode pads of the wafer W. It should be noted that at this time, the Zθ platform 21 is rotated as needed to position the electrode pads and probes.

[0082] In this state, the electrode pads of the wafer W are electrically connected to the terminals of the test head 29 via the probe 26, thus completing the preparation for the electrical test.

[0083] Next, in step S4, the communication unit 10-1 sends the status of electrical test (wafer level check) readiness (becoming in contact state) to the test head 29. Based on the contact completion signal from the detector control unit 10, the test head 29, which has confirmed the contact state, begins the electrical test.

[0084] Specifically, a voltage is applied to the electrode pads formed on the wafer W. In the contact state, the electrode pads are connected to the terminals of the test head 29 via probes 26. In power device semiconductors, the applied voltage can be higher. The test head 29 receives and analyzes the signals output from the semiconductor chip to test whether the semiconductor chip is operating normally.

[0085] It should be noted that during the testing process, the position control of the alignment device continues through a semi-closed control. Position control of the alignment device not only requires moving the wafer chuck 20 to a specified position, but also prevents positional shifts in the Zθ platform 21 and XY platform 22 caused by vibrations due to the upward movement of the Zθ platform 21, impacts during contact, and interference during contact (high voltage measurement). In other words, position control is performed even when a (high) voltage for measurement is applied. In the detector of this embodiment, since it is set to semi-closed control, noise immunity is higher, ensuring greater stability.

[0086] Next, in step S5, the electrical test ends. The voltage applied from the test head 29 to the electrode pads ends. Wafer level checks are typically performed on a per-wafer-W basis. When the inspection of one wafer W is complete, the alignment device returns the inspected wafer W to a transport unit (not shown) and receives a new wafer W from the transport unit. Therefore, when the inspection of one wafer W is complete, the alignment device is controlled to move the wafer W away from the probe card 25. Therefore, the following steps are for removing and replacing the wafer W.

[0087] Next, in step S6, the control switching unit 30-2 of the servo amplifier 30 switches the positioning of the alignment device to fully closed control. This switching is based on a control switching command 60 from the drive control unit 10-2. This control switching command 60 is typically generated when the communication unit 10-1 of the detector control unit 10 receives a signal indicating the end of the electrical test from the test head 29. In other words, at the timing when the detector control unit 10 receives the signal indicating the end of the electrical test from the test head 29 (an example of a second timing), the drive control unit 10-2 sends a command to the control switching unit 30-2.

[0088] It should be noted that the switching method from semi-closed control to fully closed control is the reverse of the above sequence.

[0089] In addition to the above definition, the second timing in this example can also be defined as follows.

[0090] • Before the Zθ platform 21 descends after the electrical test is completed • Immediately after the servo amplifier 30 receives the command for the descent of the Zθ platform 21 It should be noted that the commands used for the descent of the Zθ platform 21 can typically be received from the drive control unit 10-2 based on the upper-level commands received from the test head 29.

[0091] Next, in step S7, the servo amplifier 30 controls the servo motor 27 to lower the Zθ platform 21. This is done according to the instructions of the drive control unit 10-2. When the communication unit 10-1 receives a signal to start the electrical test from the test head 29, the drive control unit 10-2 sends the above instructions.

[0092] Next, control the XY platform 22 (step S8). The wafer chuck 20 moves to the handover position of the wafer W relative to the transport unit.

[0093] Using the aforementioned detector, at the first timing related to the start of the electrical test, the position control of the alignment device switches from fully closed control to half-closed control.

[0094] During wafer level inspection (electrical testing), the alignment device is controlled by a semi-closed control that does not use the output signal of the position detection unit. Therefore, even during high-voltage tests, the alignment device and detector can be prevented from stopping due to noise generated by the position detection unit.

[0095] In addition, since the positioning accuracy is improved because the control is switched from fully closed at the first timing related to the start of the electrical test (in other words, positioning is performed by fully closed control up to the first timing).

[0096] Furthermore, during the electrical test, the application of high voltage may introduce noise into the output signal of the position detection unit. However, this possibility virtually disappears after the electrical test. Therefore, by switching to fully closed control at the second timing, positioning accuracy is further improved.

[0097] In the example above, the first timing is the timing when the positioning of the alignment device in the XY axis direction ends, which accompanies the start of the electrical test, and the second timing is the timing when the detector control unit 10 receives the signal from the test head 29 indicating the end of the electrical test.

[0098] However, the first timing, that is, the timing for switching the positioning of the chip chuck 20 from fully closed control to semi-closed control, is not limited to the above.

[0099] Furthermore, the second timing, which switches the positioning of the chip chuck 20 from half-closed control to fully-closed control, is not limited to the above. Below, another example of the first and second timing will be explained.

[0100] Figure 5 , Figure 6 This is another flowchart illustrating the sequence of electrical tests (wafer level checks) using a detector. Figure 5 The procedure shows the sequence up to the start of the electrical test.

[0101] exist Figure 5 In the process, after the positioning of the XY platform 22 in step S1, the rising and positioning of the Zθ platform 21 in step S3 are performed. Step S1 and Figure 4 The corresponding steps in the process are the same. In addition, except that step S3 is performed through fully closed control, it is identical to... Figure 4 The corresponding steps in the process are the same.

[0102] After the Zθ platform 21 rises and positions itself, a switch to the semi-closed control in step S2 is performed. Then, in step S4, the electrical test begins. That is, in this example, the first timing occurs immediately before the electrical test.

[0103] It should be noted that "electrical test preceding" can be defined, for example, as follows.

[0104] • Immediately after the communication unit 10-1 receives the measurement start signal from the test head 29 • The contact completion signal from the detector control unit 10 is sent to the test head 29 immediately afterwards. • Immediately after the wafer chuck 20 is aligned with the specified position for the start of the electrical test It should be noted that the terms "immediately preceding" and "immediately following" are used in the examples above, but this does not imply a temporal limitation. For example, the order of actions processed in the order of A, B, and C will be described. "Execute D immediately after A" means that the processing occurs in the order of A, D, B, and C. That is, when saying "immediately after A," it means that D is inserted in between according to its relationship with B, which is processed immediately after A. The same applies to "execute D immediately before B." The same explanation applies elsewhere in this specification.

[0105] Figure 6 This is another flowchart illustrating the sequence of electrical tests (wafer level checks) using detectors, showing the order following the completion of the electrical tests. Figure 6 In the process, after the electrical test in step S5 is completed, the Zθ platform 21 is lowered in step S7. In this process, the lowering of the Zθ platform 21 in step S7 is performed through semi-closed control, which is consistent with... Figure 4 The processes are different.

[0106] Next, step S6 is performed to switch to fully closed control. Then, in step S8, the XY platform 22 moves.

[0107] In this example, the timing of the switch from half-closed control to fully closed control (the second timing) is after the Zθ platform 21 descends. "After the Zθ platform 21 descends" can be defined, for example, as follows.

[0108] • Before the start of action on the XY platform 22 • Immediately after the descent of the chip chuck 20 is completed As described above, by employing this embodiment, even for detectors performing high-voltage measurements, it is not necessary to use an expensive, high-noise-resistance linear scale 24 to prevent positional shifts in the XY platform 22 caused by impacts during contact or interference during contact (in high-voltage measurements). Furthermore, the detector of this embodiment performs semi-closed control at timings where noise can easily be mixed into the output signal of the linear scale 24, thus suppressing operational stoppages caused by errors. This improves the testing efficiency of the wafer W, achieves high throughput, and enhances positioning accuracy.

[0109] Furthermore, the switching between fully closed and partially closed control can be achieved by updating the control device's program. In other words, even detectors already installed in factories or similar locations can be used as detectors according to this disclosure simply by updating the program.

[0110] It should be noted that, Figure 4 The process and in Figure 5 , 6 The process flow describes how the first and second timings can be combined separately. In other words, it can also be used... Figure 5 Process replacement Figure 4 The steps in the electrical testing process up to the start. Alternatively, it can be used... Figure 6 Process replacement Figure 4 The steps following the completion of the electrical tests in the process.

[0111] Explanation of reference numerals in the attached figures 10: Detector control unit; 10-1: Communication unit; 10-2: Drive control unit; 20: Wafer chuck; 21: Zθ platform; 22: XY platform; 23: Ball screw; 24: Linear scale; 25: Probe card; 26: Probe; 27: Servo motor; 28: Rotary encoder; 29: Test head; 30: Servo amplifier; 30-1: Position information acquisition unit; 30-2: Control switching unit; 30-3: Motor control unit; W: Wafer.

Claims

1. A detector that performs electrical tests on a wafer, characterized in that, have: A wafer chuck, which has a holding surface for holding the wafer; A probe card having multiple probes on a surface facing the holding surface; An alignment device that positions the wafer chuck relative to the probe card; as well as Control device, The control device includes a memory, a processor, and a program stored in the memory and configured to be executed by the processor. The procedure includes, at a first timing associated with the start of the electrical test, a command to switch the position control of the alignment device from fully closed control to partially closed control.

2. The detector according to claim 1, characterized in that, The alignment device includes: A position detection unit that detects the position of the wafer chuck; A drive unit that drives the chip chuck; and A feedback sensor is located in the drive unit.

3. The detector according to claim 1 or 2, characterized in that, The first timing is before the measurement voltage for the electrical test is applied.

4. The detector according to claim 1 or 2, characterized in that, A test head is equipped with a plurality of probes that supply test signals to the wafer. The first timing occurs immediately after the control device receives the measurement start signal from the test head.

5. The detector according to claim 1 or 2, characterized in that, The first timing is achieved after the wafer chuck is positioned at a predetermined position for initiating the electrical test.

6. The detector according to claim 1 or 2, characterized in that, The alignment device is configured to allow the wafer chuck to move in the Z-axis direction opposite to the probe card and in the XY-axis direction substantially parallel to the probe card. The first timing is before the wafer chuck moves upward toward the probe in the Z-axis direction.

7. The detector according to claim 6, characterized in that, The procedure also includes a command to position the alignment device in the XY axis direction before the electrical test begins and before switching to the semi-closed control.

8. The detector according to claim 1 or 2, characterized in that, The procedure includes a command to switch the position control of the alignment device from semi-closed control to fully closed control at a second timing associated with the end of the electrical test.

9. The detector according to claim 8, characterized in that, The second timing is after the electrical test has ended, but before the wafer chuck begins to move.

10. A probe inspection method, characterized in that, include: The alignment device positions a wafer chuck holding a wafer on a holding surface relative to a probe chuck having multiple probes on a surface facing the holding surface. Electrical tests are performed on the wafer using the probes that have come into contact with the wafer; and At a first timing associated with the start of the electrical test, the position control of the alignment device is switched from fully closed control to semi-closed control.

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