Probe and its measurement method

Abstract

To ensure accurate probing while stably holding the workpiece. [Solution] The prober 1 has a chuck with an adsorption groove formed on its upper surface for applying negative pressure for adsorption. The prober measurement method comprises the steps of: placing the workpiece to be measured on the upper surface of the chuck; adjusting the adsorption force by negative pressure according to the characteristics or condition of the workpiece; and bringing the probe into contact with the workpiece to perform the measurement.

Description

Technical Field

[0001] The present invention relates to a method for measuring a work by a prober.

Background Art

[0002] A wafer on which a large number of devices are formed in a pre-process of semiconductor manufacturing is divided into a plurality of chips for each device in a dicing process. Prior to the dicing process, probing is performed to remove defective products from the devices on the wafer. Probing is a wafer-level inspection for identifying defective products by measuring the electrical characteristics of the devices formed on the wafer. The apparatus for performing this probing is a prober (see Patent Document 1).

[0003] The prober includes a probe card having probes. The probes are electrically connected to a tester. During probing, while the wafer is adsorbed to a chuck by negative pressure, the wafer is brought into contact with the probe card to bring the probes into contact with the electrodes of the device. An electrical signal is sent from the tester to the device through the probes, and whether it is a defective product is determined by inspecting its electrical characteristics.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, during the probing process, the wafer temperature rises when power is applied to the device. Due to the miniaturization and integration (higher density) of devices in recent years, the amount of heat generated by the device itself has also increased. The inventors' verification has revealed that this rise in wafer temperature affects the accuracy of probing (i.e., the determination of whether the device is good or bad) (details below). This problem is not limited to wafers; it can also occur in substrates (packages) and other workpieces on which the device is mounted.

[0006] This invention was made in view of these circumstances, and one of its objectives is to ensure the accuracy of probing while stably holding the workpiece. [Means for solving the problem]

[0007] One aspect of the present invention is a measurement method for a prober having a chuck with an adsorption groove formed on its upper surface for applying negative pressure for adsorption. This measurement method comprises the steps of: placing the workpiece to be measured on the upper surface of the chuck; adjusting the adsorption force by negative pressure according to the characteristics or condition of the workpiece; and bringing the probe into contact with the workpiece to perform the measurement.

[0008] Another aspect of the present invention is a prober that performs measurements by contacting a workpiece with a probe. This prober comprises a chuck with a suction groove formed on its upper surface for applying negative pressure to attract a workpiece, a pressure adjustment unit for adjusting the suction force due to the negative pressure, and a control unit for controlling the pressure adjustment unit. The control unit controls the pressure adjustment unit according to the characteristics or condition of the workpiece placed on the chuck and adjusts the suction force due to the negative pressure. [Effects of the Invention]

[0009] According to the present invention, it is possible to ensure the accuracy of probing while stably holding the workpiece. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view showing the schematic configuration of a prober according to an embodiment. [Figure 2] This is a schematic diagram showing the internal structure of a prober. [Figure 3] This is a diagram illustrating the structure of a zipper. [Figure 4] This is a diagram illustrating the structure of a zipper. [Figure 5] This diagram schematically shows the configuration of the pressure adjustment unit that adjusts the suction force of a vacuum. [Figure 6] This diagram schematically represents the wafer deformation that can occur during probing. [Figure 7] This diagram schematically represents the wafer deformation that can occur during probing. [Figure 8] This diagram illustrates an experiment conducted to verify the effects of adjusting the adsorption force. [Figure 9] This is a diagram showing the experimental results. [Figure 10] This is a data structure diagram of the table referenced when setting the adsorption level. [Figure 11] This is a flowchart illustrating the processing steps in the probing stage. [Figure 12] This diagram schematically shows the configuration of the pressure adjustment section in a modified example. [Figure 13] This diagram shows the structure of a chuck related to another modified example. [Figure 14] This diagram shows the structure of a chuck related to another modified example. [Modes for carrying out the invention]

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment and its modified examples, substantially identical components are denoted by the same reference numerals, and their descriptions are omitted as appropriate.

[0012] In this embodiment, suction grooves for applying negative pressure are formed on the upper surface of a chuck that supports a wafer. During probing, the wafer is adsorbed by generating an adsorption force due to negative pressure on the chuck. In particular, by adjusting the adsorption force to a necessary and sufficient value according to the characteristics or state of the wafer, deformation of the wafer is suppressed, and the contact state between the wafer and the chuck is maintained well. Thereby, heat dissipation of the wafer is promoted to prevent overheating of the device, and the accuracy of probing is ensured. Details thereof will be described below.

[0013] FIG. 1 is a perspective view showing a schematic configuration of a prober according to an embodiment. For convenience of explanation below, the left - right direction, front - rear direction, and up - down direction as viewed from the front of the device are described as the X - direction, Y - direction, and Z - direction, respectively. The prober 1 includes a housing 2 having a substantially rectangular shape in a front view and a plan view. Inside the housing 2, an inspection area 10 where inspection (measurement) of a wafer is performed is provided. Although a loader unit for transporting and unloading the wafer to and from the inspection area 10 is installed on the side of the housing 2, its illustration and description are omitted.

[0014] A head stage 4 is provided so as to form the upper surface of the housing 2. An attachment hole 14 for attaching a probe card (described later) is provided at the center of the upper surface of the head stage 4. The head stage 4 supports the probe card and is assembled to the housing 2. A tester 16 is assembled to the probe card.

[0015] The prober 1 is also provided with a control unit 20 that controls each functional part (mechanism and device) of the prober 1. The control unit 20 consists of a general - purpose computer and includes a CPU that executes various arithmetic processes, a memory or storage for storing control programs and the like, a memory used as a work area for data storage and program execution, an input / output interface, a user interface, and the like. The control unit 20 controls each functional part according to a control program.

[0016] Figure 2 is a schematic diagram of the internal structure of prober 1, showing a cross-section as indicated by arrow AA in Figure 1. The inspection area 10 is separated from external areas such as the loader area by a partition wall 21. An alignment device 22 is located in the inspection area 10. The alignment device 22 detachably supports the chuck 24.

[0017] The chuck 24 has a vacuum suction structure and fixes the wafer W by suctioning it with a vacuum source (e.g., a suction device such as a vacuum pump), which is not shown in the diagram. The devices to be inspected are arranged on the surface of the wafer W. Inside the chuck 24, there is a temperature control unit 25 that heats or cools the upper surface of the chuck 24 and, consequently, the wafer W, prior to the probing process. This allows the devices to be adjusted to a temperature appropriate to the operating environment before their electrical characteristics can be inspected.

[0018] The alignment device 22 comprises an X-table 26, a Y-table 28, and a Z-table 30. The base 6 of the housing 2 is provided with a guide rail 32 extending in the X direction. The X-table 26 is horizontally mounted so that it can move in the X direction along the guide rail 32. The X-table 26 is driven by a moving mechanism (not shown).

[0019] A guide rail 34 extending in the Y direction is provided on the upper surface of the X table 26. The Y table 28 is horizontally mounted so that it can move in the Y direction along the guide rail 34. The Y table 28 is driven by a moving mechanism (not shown). In this embodiment, each moving mechanism is realized by a screw feed mechanism and a servo motor that drives it, but it may also be realized by a linear motor.

[0020] The Z-table 30 is supported by the Y-table 28. The Z-table 30 is provided with a lifting mechanism for raising and lowering the Z-table 30 in the Z-direction and a rotation mechanism for rotating the Z-table 30 around the axis L (θ-direction) (not shown). The rotation mechanism is implemented, for example, by a spindle motor. With this configuration, the chuck 24 can move in the X-direction, Y-direction, Z-direction, and θ-direction, respectively.

[0021] A mounting hole 14 is provided in the center of the headstage 4, and a probe card 40 is detachably attached to it. The mounting hole 14 has a stepped circular shape that is complementary to the probe card 40, and is closed when the probe card 40 is fitted into it. The probe card 40 has a probe 42. The tester 16 is assembled to the headstage 4 so that it is located directly above the mounting hole 14.

[0022] The tester 16 is connected to the probe card 40 via a pogo frame 44. The pogo frame 44 functions as an interface connecting the tester 16 and the probe card 40. Specifically, the pogo frame 44 is provided with pogo pins (not shown) that electrically connect the terminals formed on the lower surface of the tester 16 (the surface facing the pogo frame 44) to the terminals formed on the upper surface of the probe card 40 (the surface facing the pogo frame 44).

[0023] The tester 16 is electrically connected to the probe 42 of the probe card 40 and supplies test signals (electrical signals) to each device on the wafer W during testing. It detects the output signals from each device to obtain their electrical characteristics. This allows the tester to check whether each device is functioning correctly. Each device also has the function of outputting its temperature information (junction temperature).

[0024] Figures 3 and 4 illustrate the structure of the chuck 24. Figure 3 is a perspective view, and Figure 4 is a schematic cross-sectional view taken along the BB arrow in Figure 3. As shown in Figure 3, the chuck 24 comprises a disc-shaped body 50 having a predetermined height. The upper surface of the body 50 constitutes a mounting surface 52 on which the wafer W is placed. Multiple suction grooves 54 are concentrically provided on the mounting surface 52 to apply negative pressure for suction. A connection port 56 for connecting piping extending from a vacuum source (not shown) is provided on the side of the body 50.

[0025] As shown in Figure 4, the main body 50 has a chuck top 60, a heater 62, and a heat sink 64. The upper surface of the chuck top 60 constitutes the mounting surface 52. The heater 62 and heat sink 64 constitute the temperature control unit 25. The heater 62 is mounted on the lower surface of the chuck top 60, and the heat sink 64 is mounted on the lower surface of the heater 62.

[0026] A suction passage 58 for vacuuming is provided slightly below the mounting surface 52 on the chuck top 60. The suction passage 58 extends parallel to the mounting surface 52 and communicates with each of the multiple suction grooves 54. The suction passage 58 is connected to a vacuum source via piping connected to a connection port 56. By driving the vacuum source, vacuuming is performed, and the negative pressure caused by the suction force acts on each suction groove 54. The negative pressure in the suction grooves 54 located on the back surface of the wafer W becomes the suction force, causing the wafer W to adhere to the mounting surface 52 (see Figure 3).

[0027] The heater 62 can heat the chuck top 60 and, consequently, the wafer W, when power is applied. The heat sink 64 has a cooling passage 66 formed therein. By flowing cooling water through the cooling passage 66, the chuck top 60 and, consequently, the wafer W can be cooled.

[0028] The main body 50 is provided with a mounting hole 68 that penetrates the heater 62 and heat sink 64 in the height direction and reaches the chuck top 60, and a temperature sensor 69 is inserted and mounted in the mounting hole 68. The temperature sensor 69 detects the temperature of the chuck 24, and more specifically, the temperature of the chuck top 60 that supports the wafer W.

[0029] Figure 5 is a schematic diagram showing the configuration of the pressure adjustment unit that adjusts the suction force of the vacuum. The prober 1 includes a pressure adjustment unit 70 that adjusts the negative pressure for adsorbing the wafer W onto the chuck 24. As described above, a pipe 74 is provided connecting the chuck 24 and the vacuum source 72, and the pipe 74 is connected to a connection port 56 (see Figure 4). The pressure adjustment unit 70 includes a pressure sensor 76 and a regulator 78.

[0030] A pressure sensor 76 is provided near the chuck 24 in the piping 74, and a regulator 78 is provided between the pressure sensor 76 and the vacuum source 72. By driving the vacuum source 72, vacuum is created and negative pressure is supplied to the chuck 24. The pressure sensor 76 detects the negative pressure (suction pressure) acting on the chuck 24. In this embodiment, the regulator 78 is an electro-pneumatic regulator and adjusts the magnitude of the negative pressure supplied to the chuck 24.

[0031] The control unit 20 sets the negative pressure (target pressure) to be applied to the chuck 24 according to the characteristics or condition of the wafer W placed on the chuck 24. The control unit 20 controls the regulator 78 so that the suction pressure (actual pressure) detected by the pressure sensor 76 approaches the target pressure (details will be described later).

[0032] Next, the measurement method using the prober 1 of this embodiment will be described. First, we will explain the problems encountered during probing that were identified through the inventors' verification, and then we will explain the countermeasures taken in this embodiment.

[0033] Figures 6 and 7 schematically illustrate the deformation (microscopic deformation) of the wafer W that may occur during probing. Figure 6 shows the case where the negative pressure acting on the wafer W is relatively large, and Figure 7 shows the case where the negative pressure acting on the wafer W is relatively small. Each figure (A) is a cross-sectional view showing the vicinity of the adsorption groove 54, and each figure (B) is an enlarged view of section C of each figure (A).

[0034] During probing, the wafer W is firmly fixed to the upper surface of the chuck 24 by the vacuum described above. At this time, the chuck 24 is adjusted to a set temperature by the temperature control unit 25. This set temperature is determined based on the operating environment of the device mounted on the wafer W.

[0035] If the suction force (i.e., negative pressure) is large at this time, microscopically, the portion of the wafer W facing the suction groove 54 deforms so that it is pulled downward (Figure 6(A)). Conversely, the portion of the wafer W between adjacent suction grooves 54 deforms so that it bulges upward. In other words, a cross-sectional wave-shaped deformation occurs in the wafer W. This deformation reduces the contact area between the wafer W and the chuck 24 (see dashed area).

[0036] On the other hand, since the device under measurement is energized on the wafer W, the device generates heat (see Figure 6(B): dashed-dot area). In other words, the temperature of the wafer W rises. In design, the chuck 24 is cooler than the heated wafer W, so heat is dissipated from the wafer W to the chuck 24, and the temperature rise is suppressed. However, according to the inventors' verification, the reduction in the contact area results in insufficient heat dissipation (see the white arrow in the figure), and the temperature of the device (junction temperature) may exceed the allowable value. If the junction temperature exceeds the allowable value, the device will be judged as defective regardless of its performance.

[0037] On the other hand, it is necessary to ensure a minimum holding force (adhesion force) so that the wafer W does not shift from the chuck 24 during probing. This minimum holding force varies depending on the characteristics and condition of the wafer W. Therefore, in this embodiment, the adhesion force due to negative pressure is adjusted for each wafer W to suppress deformation, thereby ensuring the necessary holding force for the wafer W while suppressing the temperature rise of the wafer W and preventing overheating of the device.

[0038] Specifically, a sufficient level of suction force (suction level) is set for each wafer W to prevent the negative pressure from becoming excessively large (Figure 7(A)). By adjusting the negative pressure setting to a value corresponding to that suction level, deformation of the wafer W is suppressed and heat dissipation from the wafer W is promoted (Figure 7(B)). This prevents the junction temperature from exceeding the allowable value, ensuring stable wafer W retention while maintaining probing accuracy.

[0039] Figure 8 shows an experiment conducted to verify the effect of adjusting the adsorption force. In this experiment, an experimental chip Cp (a sample with a built-in device) was prepared, and power was applied to simulate actual probing. The chip Cp was attached to the chuck 24 directly above the temperature sensor 69 (see Figure 4).

[0040] This experimental apparatus includes a power supply 80 that supplies power to the probe card 40, a thermographic camera 82 that detects the temperature of the chip Cp (chip temperature), and a temperature sensor 69 that detects the temperature of the chuck 24 (chuck temperature). Chip size: 5 x 5 mm, Applied power: 20 W (80 W / cm²) 2 The chuck temperature was set to 105°C. Under these conditions, the adsorption force (negative pressure) was changed in three stages: -90kPa, -70kPa, and -50kPa, and the change in chip temperature was observed.

[0041] Figure 9 shows the experimental results. The horizontal axis represents the suction pressure (negative pressure: kPa), and the vertical axis represents the chuck temperature (dotted line: °C) and tip temperature (solid line: °C). According to these experimental results, the chuck temperature also rises due to the heat generated by the chip Cp, but there was almost no difference when the adsorption force was changed. On the other hand, the chip temperature was significantly higher at -90kPa and decreased as the pressure was reduced to -70kPa and -50kPa. This means that when the adsorption force of the chuck 24 is large, the heat dissipation of the chip Cp is small, and the smaller the adsorption force, the more heat dissipation of the chip Cp can be promoted, which is consistent with what was explained in relation to Figures 6 and 7.

[0042] Therefore, in this embodiment, the magnitude of the negative pressure (adsorption level) is appropriately set according to the characteristics and state of the wafer W to suppress deformation of the wafer W, secure contact area with the chuck 24, and promote heat dissipation from the wafer W. As a result, the wafer W is held stably on the chuck 24 while suppressing the temperature rise of the device.

[0043] Figure 10 is a data structure diagram of the table referenced when setting the adsorption level. The control unit 20 has a pre-stored adsorption level setting table 100 that it refers to when setting the suction pressure by the pressure adjustment unit 70. The adsorption level setting table 100 has at least two adsorption levels set according to the wafer type based on the wafer characteristics and the wafer condition, and the adsorption level is associated with the suction pressure (negative pressure). The control unit 20 refers to the adsorption level setting table 100 to determine the adsorption level and adjusts the adsorption force of the wafer in steps.

[0044] In the illustrated example, adsorption levels are set for each wafer A, B, C, etc., according to their respective states. Specifically, for wafer A, the adsorption level La1 in state Xa corresponds to the suction pressure Pa1 (e.g., -90kPa), the adsorption level La2 in state Ya corresponds to the suction pressure Pa2 (e.g., -70kPa), and the adsorption level La3 in state Za corresponds to the suction pressure Pa3 (e.g., -50kPa). The magnitude of the suction pressure (negative pressure) differs depending on the adsorption level.

[0045] This adsorption level can be set, for example, using the following parameters. However, it is assumed that the minimum adsorption force necessary to fix the wafer W is obtained. (Settings based on the characteristic parameters of wafer W) • The thinner the wafer, the lower the suction level (reduce the suction pressure). • The lower the wafer's rigidity, the lower the adsorption level. • The more temperature-sensitive the wafer device, the lower the adsorption level. • The greater the frictional resistance (coefficient of friction) of the wafer, the lower the level of adsorption. • The more devices (sites) per measurement, the lower the adsorption level. (Settings based on the wafer W's state parameters (such as the environment in which the wafer W is placed)) • The higher the device temperature during probing, the lower the adsorption level. • The higher the set temperature during probing (chuck temperature), the lower the adsorption level. • The longer the current is applied during probing, the lower the suction level. • The greater the current applied during probing, the lower the adsorption level. • Differentiate the suction level depending on the method of contact of the probe (needle) with the device. • The smaller the lateral load acting on the device during contact, the lower the level of suction. To select adsorption levels in stages, selection criteria (reference values) may be established for each parameter in stages.

[0046] Figure 11 is a flowchart illustrating the processing steps in the probing process. The following explanation will be based on Figure 11, with references to Figures 2 through 5 as appropriate. The control unit 20 first sets the wafer W on the chuck 24 and drives the vacuum source 72 to adsorb the wafer W (S10). At this time, the suction pressure is not adjusted by the regulator 78. The control unit 20 acquires characteristic information of the adsorbed wafer W (S12).

[0047] Next, the control unit 20 drives the alignment device 22 to move the chuck 24 to the measurement standby position (S14). That is, it moves the chuck 24 directly below the probe card 40. Then, it starts controlling the chuck temperature (S16). That is, it controls the temperature adjustment unit 25 so that the chuck temperature detected by the temperature sensor 69 becomes the set temperature.

[0048] The control unit 20 drives the alignment device 22 to move the chuck 24 to the measurement position (S18). That is, it moves the chuck 24 so that the device to be measured comes into contact with the probe 42. Then, it energizes the device (S20).

[0049] At this time, the control unit 20 acquires the temperature information (junction temperature) of the device detected by the probe 42 (S22). Then, based on this temperature information and the characteristic information of the wafer W acquired earlier, it refers to the adsorption level setting table 100 and sets a target value for the suction pressure (target pressure) (S24). The control unit 20 acquires the actual suction pressure (actual pressure) detected by the pressure sensor 76 (S26) and controls the regulator 78 (feedback control) so that the suction pressure approaches the target pressure (S28).

[0050] During this time, the chuck temperature control continues. Specifically, the chuck temperature rises due to the heat input from the wafer W to the chuck 24. The control unit 20 controls the temperature adjustment unit 25 so that the chuck temperature is maintained at the set temperature. As a result, although the device generates heat, the temperature of the wafer W is brought close to the set temperature according to the operating environment.

[0051] When the suction pressure reaches the target pressure (Y in S30), the control unit 20 outputs the measurement result for that device (S32). Steps S18 to S32 are repeated for the next measurement until the measurement is completed for all devices that were to be inspected (N in S34). When all measurements are completed (Y in S34), the probing process is terminated.

[0052] As described above, in this embodiment, the suction pressure (adsorption level) applied to the chuck 24 is adjusted according to the characteristics or condition of the wafer W. This ensures a sufficient contact area between the wafer W and the chuck 24 during probing and promotes heat dissipation from the wafer W. Therefore, it is possible to prevent the temperature of the device being measured from exceeding an acceptable value. On the other hand, the minimum adsorption force necessary to adsorb the wafer W is ensured. In other words, according to this embodiment, the accuracy of probing (accuracy in determining good / defective products) can be ensured while stably holding the wafer W.

[0053] Although preferred embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these specific embodiments, and various modifications are possible within the scope of the technical concept of the present invention.

[0054] [Differentiation] Figure 12 is a schematic diagram showing the configuration of the pressure adjustment unit according to a modified example. In this modified example, the pressure adjustment unit 170 includes a pressure sensor 76, a regulator 78, and a control valve 92. A bypass pipe 90 is provided in the middle of the piping 74 to bypass the regulator 78. A control valve 92 (three-way valve) for switching the air flow path is provided at the connection point (branching point) between the bypass pipe 90 and the piping 74.

[0055] The suction mode can be switched by controlling the opening and closing of the control valve 92. In this modified example, two suction modes are provided: a normal mode in which the suction pressure driven by the vacuum source 72 is not particularly limited, and an adjustment mode in which the suction pressure is adjusted by the regulator 78. By controlling the opening and closing of the control valve 92, in the normal mode the passage to which the regulator 78 is located is blocked and the bypass passage by the bypass pipe 90 is opened. In the adjustment mode the bypass passage is blocked and the passage to which the regulator 78 is located is opened. The suction pressure can be adjusted by controlling the regulator 78.

[0056] Figures 13 and 14 illustrate the structure of a chuck in other modified forms. Figure 13 is a perspective view. Figure 14(A) is a cross-sectional view taken along the arrow BB in Figure 13, and Figure 14(B) is a cross-sectional view taken along the arrow CC in Figure 13. As shown in Figure 13, this modified example has different configurations of suction grooves 54 that function according to the size of the wafer. For example, consider a 12-inch wafer W1 and an 8-inch wafer W2.

[0057] The mounting surface 52 of the chuck 124 has an inner group of suction grooves 54a and an outer group of suction grooves 54b arranged concentrically. The adjacent spacing (radial spacing) of the suction grooves 54 that make up the suction groove group 54a and the suction groove group 54b is approximately equal, but there is a larger spacing between the suction groove group 54a and the suction groove group 54b.

[0058] The outer diameter of wafer W1 is larger than the outer diameter of the outer suction groove group 54b. The outer diameter of wafer W2 is smaller than the inner diameter of the outer suction groove group 54b and larger than the outer diameter of the inner suction groove group 54a. When wafer W1 is placed, negative pressure is supplied to both the suction groove group 54a and the suction groove group 54b. On the other hand, when wafer W2 is placed, negative pressure is supplied only to the inner suction groove group 54a. Connection ports 56a and 56b are provided on the side of the chuck 124.

[0059] As shown in Figure 14(A), connection port 56a communicates with the adsorption groove 54 of adsorption groove group 54a via suction passage 58a. On the other hand, as shown in Figure 14(B), connection port 56b communicates with the adsorption groove 54 of adsorption groove group 54b via suction passage 58b. Piping 74 (see Figure 5) connected to the vacuum source 72 branches before the chuck 124, with one branch of the piping connected to connection port 56a and the other connected to connection port 56b. A control valve (on-off valve) is provided in the branch pipe connected to connection port 56b, and by opening this control valve, suction from connection port 56b, that is, the supply of negative pressure to adsorption groove group 54b, becomes possible.

[0060] When wafer W1 is placed, the control unit 20 opens the control valve to supply suction pressure to both connection ports 56a and 56b and negative pressure to both adsorption groove groups 54a and 54b. On the other hand, when wafer W2 is placed, the control valve is closed to supply suction pressure only to connection port 56a and negative pressure only to adsorption groove group 54a. By limiting the number of adsorption grooves 54 that function according to the size of the wafer to the minimum necessary, the load on the vacuum source 72 can be reduced.

[0061] In this modified example, as in the above embodiment, the suction pressure (adsorption level) applied to the chuck 124 is adjusted according to the characteristics or condition of the wafer placed on the chuck 124. This ensures that the wafer W is held stably while maintaining the accuracy of the probing.

[0062] [Other variations] In the above embodiment, a wafer was used as an example of a workpiece to which the above measurement method is applied, but it may also be applied to substrates (packages) on which devices are mounted, such as FOWLP or PLP, or other workpieces. Furthermore, although not mentioned in the above embodiment, it may also be applied to wafer-on-wafer arrangements where wafers are stacked. It may also be applied to wafers held in a ring frame by dicing tape. In addition to silicon, silicon carbide (SiC) or other materials can be used as the wafer material.

[0063] In the above embodiment, a single-stage prober in which a single tester 16 is provided for the inspection area 10 was illustrated, but a multi-stage prober in which multiple testers are provided for the inspection area may also be used.

[0064] Although not mentioned in the above embodiments, the suction level may be adjusted according to the probe's needle shape when it comes to the probe's contact method with the device. For example, the suction pressure (negative pressure) may be set to -60kPa when a vertical probe is used, while the suction pressure may be set to -80kPa or higher when a cantilever probe is used. With a cantilever probe, the proportion of lateral load (horizontal load) applied to the wafer when the probe contacts the device is greater than with a vertical probe. Therefore, there is a possibility that the wafer's position may shift when the suction level is reduced. For this reason, the degree of reduction in the suction level may be reduced.

[0065] In the above embodiment, a data table (adsorption level setting table 100) is maintained as an adjustment criterion that associates information about the wafer to be measured with the adsorption level, and an example is shown in which the control unit refers to it when setting the adsorption level. In a modified example, the adjustment criterion may be defined in a program executed by the control unit.

[0066] Although not described in the above embodiment, the control unit 20 may control the pressure adjustment unit based on the temperatures of both the wafer and the chuck, and adjust the suction pressure (negative pressure) acting on the adsorption groove. Since the temperature of the chuck also changes due to the heat input from the wafer, the chuck temperature may be included as a setting parameter for the adsorption level. For example, the adsorption level may be lowered as the temperature difference between the device temperature and the chuck temperature increases.

[0067] In the above embodiments and modifications, an electro-pneumatic regulator was exemplified as the regulator 78 constituting the pressure adjustment unit 70, but a manual regulator may also be used. In that case, the user manually adjusts the regulator to adjust the suction pressure (negative pressure).

[0068] Although not described in the above embodiment, if the deviation between the target pressure and the actual pressure exceeds a predetermined allowable value during feedback control of the suction pressure, it may be determined to be a control error, and the drive of the vacuum source 72 may be stopped.

[0069] It should be noted that the present invention is not limited to the embodiments and modifications described above, and the components can be modified and implemented without departing from the spirit of the invention. Various inventions may be formed by appropriately combining the multiple components disclosed in the embodiments and modifications described above. In addition, some components may be deleted from all the components shown in the embodiments and modifications described above. [Explanation of Symbols]

[0070] 1 Prober, 4 Headstage, 6 Base, 10 Inspection Area, 14 Mounting Holes, 16 Tester, 20 Control Unit, 22 Alignment Device, 24 Chuck, 25 Temperature Control Unit, 26 X Table, 28 Y Table, 30 Z Table, 40 Probe Card, 42 Probe, 44 Pogo Frame, 52 Mounting Surface, 54 Suction Groove, 56 Connection Port, 58 Suction Passage, 60 Chuck Top, 62 Heater, 64 Heat Sink, 66 Cooling Passage, 68 Mounting Holes, 69 Temperature Sensor, 70 Pressure Adjustment Unit, 72 Vacuum Source, 74 Piping, 76 Pressure Sensor, 78 Regulator, 90 Bypass Pipe, 92 Control Valve, 170 Pressure Adjustment Unit, Cp Chip, W Wafer.

Claims

1. A method for measuring probes having a chuck with an adsorption groove formed on its upper surface for applying negative pressure for adsorption, The steps include: placing the workpiece to be measured on the upper surface of the chuck, A step of adjusting the suction force due to the negative pressure according to the characteristics or condition of the workpiece, The steps include: bringing a probe into contact with the workpiece and taking a measurement; A probe measurement method comprising the following.

2. The probe measurement method according to claim 1, wherein the step of adjusting the adsorption force is to adjust the adsorption force based on the temperature of the workpiece at the time of measurement.

3. The probe measurement method according to claim 2, wherein the step of adjusting the adsorption force is to acquire temperature information of the workpiece by bringing the probe into contact with the workpiece.

4. The probe measurement method according to claim 1, wherein the step of adjusting the suction force is to adjust the suction force based on the magnitude of the frictional resistance of the workpiece that contacts the upper surface of the chuck.

5. At least two levels are set as the adjustment level for the adsorption force. The probe measurement method according to any one of claims 1 to 4, wherein the step of adjusting the adsorption force involves adjusting the adsorption force in stages according to the characteristics or condition of the workpiece.

6. A prober that performs measurements by contacting the workpiece with a probe, A chuck having a suction groove formed on its upper surface for applying negative pressure to adsorb the workpiece, A pressure adjustment unit for adjusting the adsorption force due to the negative pressure, A control unit that controls the pressure adjustment unit, Equipped with, The control unit controls the pressure adjustment unit according to the characteristics or condition of the workpiece placed on the chuck, and adjusts the suction force due to the negative pressure, thereby providing a probe.

7. The control unit, Maintain an adjustment standard that associates information about the workpiece to be measured with the level of the adsorption force, The prober according to claim 6, which acquires information about a workpiece placed on the chuck, identifies a level corresponding to the acquired workpiece information based on the adjustment criteria, and controls the pressure adjustment unit so that the suction force is at the identified level.

8. The system includes a pressure sensor that detects the negative pressure supplied to the chuck, The prober according to claim 7, wherein the control unit performs feedback control so that the pressure detected by the pressure sensor approaches a target pressure corresponding to the level of the adsorption force.

9. The system includes a temperature adjustment unit that adjusts the temperature of the chuck by heating or cooling it. The prober according to claim 6, wherein the control unit controls the pressure adjustment unit based on the temperatures of both the workpiece and the chuck.

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