JP5197145B2 - Probe position correcting method and prober - Google Patents

Description

  The present invention relates to a prober used for inspecting a plurality of semiconductor devices (chips) formed on a wafer by a tester, and the amount of movement of a stage for bringing a plurality of probes of a probe card into contact with a plurality of electrode pads. The present invention relates to a probe position correcting method and a prober to be corrected.

  The semiconductor manufacturing process has a large number of processes, and various inspections are performed in various manufacturing processes in order to guarantee quality and improve yield. For example, when a plurality of chips of a semiconductor device are formed on a semiconductor wafer, electrode pads of the semiconductor device of each chip are connected to a tester, a power source and a test signal are supplied from the tester, and a signal output from the semiconductor device is Wafer level inspection is performed in which a tester is used to electrically inspect whether the device operates normally.

  After wafer level inspection, the wafer is affixed to the frame and cut into individual chips with a dicer. For each chip that has been cut, only chips that have been confirmed to operate normally are packaged in the next assembly process, and defective chips are excluded from the assembly process. Further, the packaged final product is subjected to shipping inspection.

  FIG. 1 is a diagram showing a schematic configuration of a system for performing wafer level inspection. The wafer level inspection system includes a prober for bringing the probe 11 into contact with an electrode pad of each chip on the wafer, and a power supply and a test signal supplied to each chip for electrical inspection. And a tester 5 that detects whether the chip operates normally by detecting an output signal from each chip. Reference numerals 1 to 4 are parts constituting the prober housing. A probe card 12 having a probe 11 that contacts an electrode pad and a wafer alignment camera 13 are attached to the upper plate 4 of the housing. The base 1 is provided with a moving mechanism 24 that moves the stage 22. The stage 22 is provided with a wafer chuck 21 that holds the wafer 100 by vacuum suction or the like, and a probe position camera 23 that detects the position of the probe 11 of the probe card 12. The wafer chuck 21 is not only movable in the three-axis direction by the moving mechanism 24 but also rotatable about the vertical axis. The wafer alignment camera 13 may be attached to the support plate 3 of the housing.

  The tester 5 is placed on the upper plate 4 of the housing of the prober. The electrical terminal of the tester 5 is connected to the terminal of the probe card 12 and is electrically connected to the probe 11. The tester 5 and the prober are separate products, and the user configures the wafer level inspection system by appropriately combining the tester 5 and the prober according to the chip formed on the wafer. Moreover, the probe card 12 needs to be provided with the probe 11 arranged corresponding to the electrode pad of the chip to be inspected, and is appropriately replaced according to the chip (semiconductor device).

  Images taken by the wafer alignment camera 13 and the probe position camera 23 are sent to the image processing / arithmetic processing unit 31. The image processing / arithmetic processing unit 31 detects the position of the electrode pad of each chip of the wafer 100 held by the wafer chuck 21 from the image of the wafer alignment camera 13, and from the image of the probe position camera 23, the probe card 1. The position of the probe 11 is detected. The image processing / arithmetic processing unit 31 sends data relating to the detected position of the electrode pad of each chip and the position of the probe 11 of the probe card 1 to the movement control unit 32. The movement control unit 32 includes a movement amount calculation unit 33 that calculates the movement amount of the stage 22 necessary to bring the predetermined position of the electrode pad into contact with the probe 11 based on these data. The movement control unit 32 controls the movement mechanism 24 based on the movement amount calculated by the movement amount calculation unit 33 and moves the stage 22 to bring the electrode pad into contact with the probe 11.

  Although only the movement control unit 32 is shown here, a control unit that performs various controls such as temperature adjustment and rotation of the wafer chuck 21 is actually provided, and the movement control unit 32 is a part of the control unit. Composed. The control unit is configured by a computer. The image processing / arithmetic processing unit 31 displays the image of the wafer alignment camera 13 and the image of the probe position camera 23 on the display device 34 as they are or after image processing. The operator performs various settings and operations while viewing the image on the display device 34.

  FIG. 2 is a diagram showing the configuration of the probe card 12 portion. A head stage 15 is provided on the upper plate 4 of the prober housing, and a card holder 14 is provided on the head stage 15. The probe card 12 having the probe 11 needs to be replaced according to the chip to be inspected as described above, and is detachably attached to the card holder 14.

  When the probe 11 is brought into contact with the electrode pad, the wafer chuck 21 holding the wafer 100 is moved in the XY plane so that the electrode pad is located immediately below the probe 11, and then the wafer chuck 21 is raised in the Z-axis direction. The electrode pad is brought into contact with the probe 11. At this time, a voltage is applied to the terminal of the tester connected to the probe 11 so that it can be detected that the probe 11 has contacted the electrode pad, and control is performed so as to stop the raising of the wafer chuck 21.

  The configuration of the conventional wafer level inspection system has been described above. However, since the wafer level inspection system is described in, for example, Patent Documents 1 and 2, further description thereof is omitted here.

  In recent years, semiconductor devices (chips) have been highly integrated and miniaturized, and the size of electrode pads and the spacing between arrays have been reduced accordingly. Therefore, high accuracy is required for the alignment between the probe 11 and the electrode pad. In order to improve inspection throughput, a probe card is provided with probes for a plurality of chips, and multi-probing is performed in which a plurality of chips are simultaneously inspected by a single contact operation. The number of probes provided on the probe card for multi-probing has increased, but in recent years the number of chips to be inspected at the same time has increased rapidly, and the number of probes has increased dramatically accordingly, with tens of thousands of probes. In some cases.

  As described above, the arrangement of the probe 11 of the probe card 12 is different for each chip to be inspected, and it is necessary to replace the probe card 12 according to the chip to be inspected. The probe card 12 is fitted and attached to the card holder 14, but the positional accuracy is defined by a fitting error. Also, the position of the probe itself has a position error. Furthermore, the probe is made of a thin spring material, and the probe position changes when contact with the electrode pad is repeated. On the other hand, the wafer is held on the wafer chuck by vacuum suction or the like, but the holding position cannot be managed with high accuracy.

  Therefore, as shown in FIG. 1, the prober photographs each chip of the wafer held on the wafer chuck by the wafer alignment camera 13, and recognizes the position of the electrode pad of each chip by image processing. The wafer alignment camera 13 takes a microscopic image of the chip and can recognize the position of the electrode pad with high accuracy. Similarly, by processing the image of the probe 11 of the probe card 12 taken by the probe position camera 23, the position of the probe 11 can be recognized with high accuracy.

  FIG. 3 is a diagram for explaining the calculation processing of the movement amount for bringing the electrode pad into contact with the probe 11 based on the position of the electrode pad and the position of the probe 11 recognized as described above. Here, calculation of the movement amount only in the uniaxial (X-axis) direction will be described, but the same applies to the biaxial direction.

  FIG. 3A shows a state in which the axis of the wafer alignment camera 13 and the axis of the probe position camera 23 coincide. In other words, the origin of the image of the wafer alignment camera 13 and the origin of the image of the probe position camera 23 coincide with each other. It is assumed that the moving mechanism at this time indicates the moving position R. The moving mechanism does not need to move until the axis of the probe position camera 23 actually coincides with the axis of the wafer alignment camera 13, and when the axis of the wafer alignment camera 13 and the axis of the probe position camera 23 coincide virtually. It is sufficient if the movement position R of the movement mechanism can be defined.

  Next, as shown in FIG. 3B, the probe position camera 23 is moved below the probe 11A of the probe card 12, and the position of the probe 11A in the image of the probe position camera 23 is detected. Actually, a plurality of probes of the probe card 12 are provided according to the number of electrode pads of the chip, and the positions of all the probes are detected. Here, in order to simplify the explanation, it is assumed that there is one probe and is located at the origin of the image of the probe position camera 23, and the movement position of the movement mechanism at that time is S1. Therefore, the distance between the axis of the wafer alignment camera 13 and the probe 11A is S1-R.

  Next, as shown in FIG. 3C, the wafer 100 is moved below the wafer alignment camera 13, and the wafer chuck 21 is moved so that the arrangement direction of the chip electrode pads coincides with the arrangement direction of the probes 1. After the rotation, the position of the electrode pad of the chip is detected. A plurality of chip electrode pads are also provided, and the positions of all the electrode pads are detected. A plurality of chips are formed on the wafer 100, and it is necessary to detect the position of the electrode pad of each chip. In practice, however, the chips are regularly arranged with high positional accuracy, and some chips In some cases, the positions of the electrode pads are detected, and the electrode pad positions of other chips are calculated.

  If there are multiple electrode pads, determine whether multiple probes are in positions corresponding to multiple electrode pads, and whether multiple electrode pads can contact multiple probes. Calculate the relationship. This positional relationship is a positional relationship in which the position of each electrode pad varies and the position of each probe varies, so that the difference between the corresponding electrode pad of each probe and the predetermined position is minimized as a whole. Here, for explanation, it is assumed that there is one electrode pad, which is located at the origin of the image of the wafer alignment camera 13, and the movement position of the movement mechanism at that time is S2.

  The electrode pad is located at the origin of the image of the wafer alignment camera 13, and the electrode pad is brought into contact with the probe 11A that is S1-R away from the origin of the image of the wafer alignment camera 13 as shown in FIG. That is, it is only necessary to move the moving position of the moving mechanism from the state of S2 by S1-R. FIG. 3D shows a state where the moving position of the moving mechanism is S1 + S2-R. At this time, the electrode pad of the chip is located immediately below the probe 11A. 11A contacts a predetermined position of the electrode pad.

  The movement amount for bringing the electrode pad into contact with the probe (probe) of the probe card is calculated as described above. For the calculation, it is necessary to measure the positional relationship between the wafer alignment camera 13 and the probe position camera 23. Therefore, a specialized operator uses the wafer and probe card used for actual measurement to bring the electrode pad into contact with the probe and observe the probe contact trace (probe trace) on the electrode pad to measure the positional relationship. Had gone. However, this operation is difficult because it is difficult to recognize the probe traces, and there is a problem that the operator who can perform the operation is limited, the operation time is long, and the accuracy is insufficient.

  In order to solve such a problem, Patent Documents 1 and 2 capture an image of the probe trace of the electrode pad with a wafer alignment camera, and perform image processing on the image captured by the image processing / arithmetic processing unit 31 to obtain the probe trace. recognize. Then, the deviation amount between the center of the recognized probe trace and the electrode pad is calculated, and the actual positional relationship between the electrode pad and the probe is measured from this deviation amount. Such probe mark inspection is referred to as PMI (Probe Mark Inspection).

  The PMI process is periodically performed during the probing operation in order to prevent the electrode pad from being broken and inspected due to misalignment of the probing position. As described above, the positional relationship between the electrode pad and the probe trace is measured by image processing. If the probe trace is closer to the electrode pad frame than the safety margin defined by parameters etc., an alarm is generated and probing is interrupted. In general, the operator is prompted to correct the probe position.

Japanese Unexamined Patent Publication No. 7-13990 JP 2004-63877 A

  In the conventional PMI processing described in Patent Documents 1 and 2, the center of the probe trace recognized by image processing is obtained, and the positional relationship is corrected so that the deviation from the center of the electrode pad falls within a predetermined range. . However, it is particularly important that the probe does not protrude from the frame (edge) of the electrode pad in order to prevent destruction of the electrode pad and occurrence of defective inspection due to probing misalignment or the like. Of course, the deviation between the center of the probe trace and the center of the electrode pad is related to the positional relationship of the probe trace with respect to the frame of the electrode pad, but does not completely match.

  As shown in FIG. 2, the probe 11 extends in an oblique direction with respect to the surface of the wafer 100, and after the surface of the wafer 100 comes into contact with the tip of the probe 11, the surface of the wafer 100 rises by a small amount. Thus, the contact position of the probe 11 is slightly shifted in the horizontal direction. This shift operation generates a probe mark. Further, a contact pressure is generated by a small increase after contact. As described above, there are multiple probes, and the tip positions of all probes are not perfectly aligned, and the spring characteristics are different, so all the probes are in contact with the electrode pads, and the contact pressure of all the probes is predetermined. The wafer is further lifted by a small amount so as to fall within the range. However, the contact pressure and the amount of deviation in the horizontal direction vary from probe to probe. For example, if the displacement in the horizontal direction is large due to a large contact pressure, the probe trace also becomes large. Even if the deviation between the center of the probe trace and the center of the electrode pad is small, the distance of the probe trace to the electrode pad frame is Get smaller. As described above, it is not sufficient to make correction based on the deviation between the center of the probe mark and the center of the electrode pad as in the prior art.

  In addition, as described in Patent Documents 1 and 2, it has been proposed to automatically correct the movement amount based on the deviation between the center of the probe trace and the center of the electrode pad. Since it was difficult to accurately recognize the traces, it was difficult to correct with high precision. Therefore, as described above, when the probe mark is closer to the electrode pad frame than the safety margin, an alarm is generally generated to prompt the operator to correct the probe position. In this case, since the operator finally recognizes the probe trace, the problem of the probe trace recognition error due to the image processing can be avoided.

  However, when an alarm occurs, the operator needs to correct the positional relationship in consideration of the correction direction and the correction amount from the probe marks attached to a large number of electrode pads. For example, it is necessary to observe the image of the probe trace of the electrode pad in order, remember the electrode pad where the probe trace is close to the frame in particular, and determine the optimal correction direction and correction amount as a whole, which requires very skill. It was work. Therefore, the correction of the positional relationship has a high risk of causing individual differences and errors.

  An object of the present invention is to solve such a problem and to make it possible to correct the positional relationship in a more practical manner.

  Another object of the present invention is to facilitate the correction process so that problems such as individual differences and errors do not occur when an operator corrects a positional relationship.

  To achieve the above object, in the probe position correcting method and prober of the present invention, a plurality of electrode pad frames of a plurality of probe traces in four directions of ± X direction and ± Y direction in a plane parallel to the surface of the wafer. And calculating the minimum margin distance for each of the four directions, and correcting the contact positions of the plurality of electrode pads and the plurality of probes based on the minimum margin distance in the four directions.

  That is, according to the probe position correcting method of the present invention, the wafer on which a plurality of electrode pads are formed is moved relative to the plurality of probes of the probe card in the three axial directions of X, Y, and Z to A probe position correcting method for correcting the contact positions of the plurality of electrode pads and the plurality of probes when the electrode pad and the plurality of probes are brought into contact with each other, wherein the plurality of electrode pads and the plurality of probes are brought into contact with each other. , And processing the probe trace image of the plurality of probes on the plurality of electrode pads to detect the probe trace, and the plurality of probe traces in four directions of ± X direction and ± Y direction. A margin distance with respect to the frame of the electrode pad is calculated, a minimum margin distance is calculated for each of the four directions, and the plurality of electrode pads are calculated based on the minimum margin distance in the four directions. The contact position of the probe and the plurality of probes is corrected.

  According to the present invention, the contact positions of the plurality of electrode pads and the plurality of probes are corrected based on the minimum marginal distances in four directions with respect to the electrode pad frame of the probe traces that are practically necessary. Can be further prevented.

  Also, when the minimum marginal distance in the four directions is less than the predetermined amount and an alarm is generated to prompt the operator to correct it, the minimum marginal distance in the four directions is calculated on the monitor after calculating the minimum marginal distance in the four directions. By allowing the operator to make corrections based on the minimum marginal distances in the four directions displayed graphically, the correction is facilitated. When graphically displaying the minimum margin distance in the four directions on the monitor, it is desirable to display an image including the probe trace of the electrode pad for which the minimum margin distance in the four directions is calculated together on the monitor. Thereby, the operator can easily confirm the probe trace of the electrode pad determined as the minimum margin distance in the four directions by the image processing.

  It should be noted that a correction method based on the minimum margin distance in four directions with respect to the electrode pad frame of the probe trace that is practically necessary can also be applied when correction is automatically performed.

  Further, the prober of the present invention includes a probe card having a plurality of probes, a wafer chuck for holding a wafer on which a plurality of electrode pads are formed, and a movement for moving the wafer chuck in three axial directions of X, Y, and Z. A mechanism, probe position detecting means for detecting the position of the probe on the probe card, wafer alignment means for detecting positions of a plurality of electrode pads of the wafer held by the wafer chuck, and controlling the moving mechanism A movement control unit, wherein the movement control unit is based on the positions of the plurality of probes detected by the probe position detection unit, the positions of the plurality of electrode pads detected by the wafer alignment unit, and a movement amount calculation correction value. The amount of movement by the moving mechanism is set so that predetermined positions of the plurality of electrode pads are brought into contact with the plurality of probes. A prober comprising a moving amount calculation unit for calculating, wherein the wafer alignment means detects a position of the probe trace by processing an image of the probe trace that has contacted the plurality of probes on the plurality of electrode pads. The probe trace detecting means calculates the margin distance of the probe trace with respect to the frame of the plurality of electrode pads for the four directions of ± X direction and ± Y direction, and calculates the minimum margin distance for each of the four directions. Margin distance calculation means, wherein the movement amount calculation unit calculates a movement amount calculation correction value based on the minimum margin distance in the four directions.

  According to the present invention, since the positional relationship between the probe and the electrode pad can be corrected in a practically necessary form, it is possible to further prevent the electrode pad from being broken and the inspection failure from occurring. Further, according to the present invention, when the operator corrects the positional relationship, the correction operation becomes easy and errors caused by the operator can be reduced.

  The prober according to the embodiment of the present invention has the overall configuration as shown in FIG. 1 and executes the present invention on a computer constituting the image processing / arithmetic processing unit 31, the movement control unit 32, and the movement amount calculating unit 33. The difference is that the program is installed.

  FIG. 4 is a flowchart showing the prober movement amount correction processing of this embodiment. FIG. 5 is a diagram showing an example of an electrode pad with a probe mark, four electrode pads having a minimum margin distance from the probe mark to the electrode pad frame, and a graphical display.

  In step 201, the wafer is moved and the electrode pad is brought into contact with the probe 11 to generate a probe mark. As a result, as shown in FIG. 5A, the probe mark T is attached on the electrode pad.

  In step 202, the chips on the wafer 100 are sequentially moved so as to be positioned below the alignment camera 13, and the alignment camera 13 images the electrode pads of each chip.

  In step 203, the probe trace of the electrode pad is recognized by image processing in the photographed image. At this time, the position of the frame of the electrode pad is also recognized.

  In step 204, the distance of the recognized probe trace to the electrode pad frame is calculated. Specifically, as shown in FIG. 5B, the probe trace T is recognized at each electrode pad, and the difference between the minimum value of the X coordinate and the X coordinate of the left edge of the frame is −X margin. The difference between the maximum value of the distance a and the X coordinate and the X coordinate of the right edge of the frame is + X margin distance b, and the difference between the minimum value of the Y coordinate and the Y coordinate of the upper edge of the frame is + Y margin distance c and Y The difference between the maximum coordinate value and the Y coordinate of the lower edge of the frame is calculated as -Y margin distance d. These four values are calculated for probe traces of all electrode pads.

  In step 205, a minimum distance is determined for each of the calculated probe traces a to d of all electrode pads. 5 (B) shows an electrode pad with a minimum value a of −X margin distance, FIG. 5C shows an electrode pad with a minimum value e of + X margin distance, and FIG. 5D shows a + Y margin. FIG. 5E shows an electrode pad whose distance is the minimum value f, and FIG. 5E shows an electrode pad whose −Y margin distance is the minimum value g.

  In step 206, the electrode pad with the smallest margin distance in the four directions from (B) to (E) in FIG. 5 is displayed on the monitor. Thereby, the operator can confirm the image of the probe trace in which the margin distance is determined to be minimum. For example, when it is determined that the margin distance is determined to be minimum by image processing but is not appropriate from the displayed image, It is possible to take measures such as reprocessing except for the electrode pads. Thereby, it is possible to prevent erroneous determination due to a recognition error caused by image processing of the probe trace.

  In step 207, as shown in FIG. 5F, a frame R indicating a portion where the electrode pads P and Q in two directions overlap with each other, and the minimum marginal distances a, e, and A portion S separated by f and g is displayed.

  When the operator performs correction by manual operation, the operation is performed so that the portion S is positioned at the center of the frame R. The operator can easily adjust the positional relationship while looking at the electrode pads determined to be the minimum margin distances in the four directions by image processing.

  When the positional relationship is automatically adjusted, the positional relationship is corrected so that a and e and f and g are equal.

  When the sum of a and e and the sum of f and g are less than a predetermined value, normal probing is difficult and an alarm is generated.

  The process of recognizing probe traces by image processing is desirably performed for all probes. However, when the number of probes increases, it takes a very long time to perform the probe trace recognition process for all probes. Therefore, some of all probes may be selected to perform a process for recognizing a probe trace, and the above process may be performed for them. At that time, some probes having a large positional deviation in the ± X and ± Y directions may be selected from the probe positions detected by the probe position camera 23, and the probe traces may be detected.

  The display shown in FIG. 5F for the operator to correct the positional relationship can be variously modified. For example, as shown in FIG. 6, XY coordinates including the origin O are displayed on the monitor and pass through (−a, 0), (e, 0), (0, f), and (0, −g), respectively. You may make it display the rectangle W represented by the line of the X and Y direction to do. The position correction is performed so that the origin moves to the center of the rectangle W. In addition, the larger the square W, the greater the positioning margin.

  Further, the electrode pad is not limited to a quadrangle as shown in FIG. 5, but may be an octagon as shown in FIG. 7 or other shapes. The moving mechanism 24 that moves the stage 22 can rotate about the three-axis direction and the Z-axis, but the positional relationship to be corrected here is related to the X and Y directions. Let the distance from the contact to the frame of the electrode pad when moving in the Y direction be a margin distance a to d.

  Although the embodiments of the present invention have been described above, it goes without saying that various modifications are possible.

  As described above, according to the present invention, since the practical accuracy when the electrode pad is brought into contact with the probe of the probe card by the prober is improved, the wafer inspection in which the semiconductor device (chip) having the finer electrode pad is formed. Can be applied to.

It is a figure which shows the whole structure of the conventional wafer level inspection system. It is a figure explaining the structure of the attachment part of a probe card. It is a figure explaining the alignment in a prober. It is a flowchart which shows the movement amount calibration process of an Example. It is a figure which shows the example of a display of the electrode pad, the probe trace, the electrode pad of the minimum margin distance, and the minimum margin distance for correction. It is a figure which shows the other example of the display of the minimum margin distance for correction. It is a figure which shows the example of an octagonal electrode pad.

Explanation of symbols

1-4 Housing 5 Tester 11 Probe 12 Probe Card 13 Wafer Alignment Camera 21 Wafer Chuck 22 Stage 23 Probe Position Camera 31 Image Processing / Calculation Processing Unit 32 Movement Control Unit 33 Movement Amount Calculation Unit 34 Display Device

Claims (4)

This is executed by a computer constituting the control unit of the prober, and the wafer on which the plurality of electrode pads are formed is moved relative to the plurality of probes of the probe card in the X, Y, and Z directions, and the plurality A probe position correcting method for correcting the contact positions of the plurality of electrode pads and the plurality of probes when the electrode pad and the plurality of probes are contacted,
Contacting the plurality of electrode pads and the plurality of probes;
Processing an image of probe traces in contact with the plurality of probes on the plurality of electrode pads to detect the probe traces;
For the four directions of ± X direction and ± Y direction, calculate margin distances of the probe marks with respect to the plurality of electrode pad frames,
Calculating a minimum margin distance for each of the four directions;
The contact position of the plurality of electrode pads and the plurality of probes is corrected so that the two minimum margin distances in the X direction and the two minimum margin distances in the Y direction are equal to each other. Position correction method. This is executed by a computer constituting the control unit of the prober, and the wafer on which the plurality of electrode pads are formed is moved relative to the plurality of probes of the probe card in the X, Y, and Z directions, and the plurality A probe position correcting method for correcting the contact positions of the plurality of electrode pads and the plurality of probes when the electrode pad and the plurality of probes are contacted,
Contacting the plurality of electrode pads and the plurality of probes;
Processing an image of probe traces in contact with the plurality of probes on the plurality of electrode pads to detect the probe traces;
For the four directions of ± X direction and ± Y direction, calculate margin distances of the probe marks with respect to the plurality of electrode pad frames,
Calculating a minimum margin distance for each of the four directions;
A probe position correcting method, wherein the minimum marginal distance in the four directions is displayed in a graphic form on a monitor.   The probe position correcting method according to claim 2, wherein an image including a probe trace of the electrode pad whose minimum margin distance in the four directions is calculated is displayed on the monitor. A probe card having a plurality of probes; a wafer chuck for holding a wafer on which a plurality of electrode pads are formed; a moving mechanism for moving the wafer chuck in three axial directions of X, Y, and Z; Probe position detection means for detecting the position of the probe, wafer alignment means for detecting the positions of the plurality of electrode pads of the wafer held by the wafer chuck, and a movement control unit for controlling the movement mechanism, The movement control unit is configured to determine a predetermined value of the plurality of electrode pads based on the positions of the plurality of probes detected by the probe position detection unit, the positions of the plurality of electrode pads detected by the wafer alignment unit, and a movement amount calculation correction value. A movement amount calculation unit for calculating a movement amount by the movement mechanism so as to bring the position into contact with the plurality of probes; A prober,
The wafer alignment means includes
Probe trace detection means for detecting the position of the probe trace by processing an image of the probe trace in contact with the plurality of probes on the plurality of electrode pads;
A minimum margin distance calculating means for calculating a margin distance of the probe trace with respect to the frame of the plurality of electrode pads in four directions of ± X direction and ± Y direction, and calculating a minimum margin distance for each of the four directions; With
The prober according to claim 1, wherein the movement amount calculation unit calculates a movement amount calculation correction value so that the two minimum margin distances in the X direction and the two minimum margin distances in the Y direction are equal to each other .

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