JP2016212014A - Offset information acquisition method of probe, and x-y substrate inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which, when offset information of a probe of an X-Y substrate inspection device is acquired using a scratch sheet, a plurality of scratches are formed on the same sheet and hence it becomes difficult to determine which scratch is the scratch of the probe to be acquired.SOLUTION: An image of the scratch sheet taken when the offset information is acquired last time is acquired, then a scratch is formed by a probe and its image is acquired, the difference between it and the last image is taken, and offset information of the probe is acquired from the image information of the present scratch.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a probe offset information acquisition method and an XY substrate inspection apparatus.

  As an inspection apparatus for a printed wiring board or the like, an XY board inspection apparatus that performs inspection by bringing a movable probe into contact with a substrate to be inspected is known. This XY substrate inspection device inspects a probe at a target position by moving a movable head mounted with a probe called a flying probe, which is brought into contact with a substrate to be inspected, on an XY plane (secondary plane). An inspection is performed by contacting the target substrate. An inspection probe is mounted on the movable head so as to be movable up and down in the Z-axis direction orthogonal to the XY plane. By contacting the probe with a predetermined inspection point on the inspection target substrate, the electrical Inspection can be performed.

As a drive mechanism for moving the movable head back and forth on the XY plane, an XY orthogonal two-axis drive mechanism is known. A Y-axis drive unit for moving the movable head with a ball screw, and this Y-axis drive unit. An X-axis drive unit that moves with a ball screw in the X-axis direction orthogonal to the Y-axis is provided, and the movable head can be moved to a predetermined XY coordinate position by control from the control device.
The movable head is provided with a camera, and the camera can determine whether the probe has accurately reached the position to be measured.

By the way, since the probe is a consumable product that is worn out by inspection, it needs to be replaced with a new probe when wear or the like occurs during inspection.
When the probe is changed, the position where the tip of the probe hits the substrate changes slightly. Due to the play and accuracy of the probe mounting mechanism, or the difference in the probe mounting angle, the position of the substrate that contacts the probe deviates from the probe before replacement. This deviation is about several μm, but in a substrate inspection apparatus with a position control accuracy of about 1 μm, the deviation is large enough to affect the inspection result.

  For this reason, when the probe is replaced, it is necessary to detect the deviation of the attached probe from the probe prior to replacement and correct the target coordinate value to be instructed. Therefore, the probe offset position information is detected before inspection. In the subsequent inspection process, the offset of the probe is compensated to correct the target coordinates (target position).

  As a method for acquiring the offset information of the probe, there is a method using a dent sheet. This method will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an outline of an XY orthogonal two-axis drive mechanism of an XY substrate inspection apparatus using a flying probe. The XY orthogonal two-axis drive mechanism includes a Y-axis drive unit 14 that moves the movable head 17 in the Y-axis direction, an X-axis drive unit 10 that moves the Y-axis drive unit 14 in the X-axis direction, and a control device 20. With. The X-axis drive unit 10 rotationally drives the X-axis ball screw 11 by the X-axis servomotor 12 under the control of the control device 20. Similarly, the Y-axis drive unit 14 controls the movement of the movable head 17 by rotationally driving the Y-axis ball screw 15 by the Y-axis servomotor 16 under the control of the control device 20. A probe 18 that can be moved up and down in the Z-axis direction is mounted on the movable head 17. Further, the movable head 17 is provided with a camera 19, and an image of a point on the substrate where the probe 18 descends can be taken to determine a deviation from the target coordinate value instructed to move. The probe 18 and the camera 19 are also controlled by the control device 20.

  An offset acquisition board 22 for acquiring probe offset information is provided at the end of the stage 21 on which the substrate of the XY substrate inspection apparatus is mounted. As shown in FIG. 2, the offset acquisition board 22 can affix a plurality of dent sheets 23 at predetermined positions.

  The dent sheet 23 uses a pressure sensitive paper of about 2 cm square. When the probe 18 is lowered, the dent sheet 23 has a mark on the tip of the probe at the lowered position. The offset information acquisition board is made of an epoxy substrate, for example, and indicates an area where a plurality of dent sheets can be pasted. The position where the offset information acquisition board is provided on the stage 21 is predetermined by the manufacturer.

  The offset information of the probe is obtained by hitting a dent sheet with the probe 18, capturing an image of the dent with the camera 19, and by image processing, a deviation amount (distance) between the dent position and the optical axis (center axis) of the camera. Detect and get The amount of deviation between the dent position and the optical axis of the camera is the difference between the designated target coordinate position and the dent position that was actually struck and moved. Based on this deviation amount, the probe before replacement Is used as offset information to compensate the target coordinates instructed to the probe in the inspection process.

The operation of acquiring the offset information will be described with reference to FIGS.
In acquiring the probe offset information, when the probe 18 is replaced, the movable head 17 is moved onto a predetermined dent sheet 23 to indicate the dent. The move instruction coordinate value to the dent sheet 23 for acquiring the offset information is initially set by the manufacturer in advance. However, since the user can set the coordinate position instruction for acquiring the offset information from the second time, the instruction coordinate position for acquiring the offset information is changed when the probe is replaced, and the dent coordinate position is moved. Is possible.

  First, when the probe is moved onto the dent sheet and the dent is made, the camera 19 is moved onto the image of the dent, the dent image is captured by the camera, and the captured dent image is processed. The deviation from the coordinate value instructed to move is acquired by image processing. Since this deviation amount becomes offset information of the probe, at the time of substrate inspection, this offset information is used to compensate the target position coordinate value for substrate inspection.

JP-A-6-331653

  When acquiring the offset information by exchanging the probe 18 in the middle after starting the substrate inspection, the user changes the specified coordinate position for acquiring the offset information, and changes the dent position of the probe. The offset information can be acquired by changing the image by a little, for example, 1 mm to acquire the image of the dent. This means that the same dent sheet is used several times for obtaining offset information. This is because, if the dent sheet is replaced by stopping the apparatus to acquire the offset information, the work efficiency is deteriorated and the dent sheet that can still be used is wasted.

  For this reason, since the same dent sheet is struck multiple times, when a dent image is captured by the camera, a plurality of dents are formed on the same dent sheet as shown in FIG. Will be left behind. Then, when the operator operates the camera to pick up an image of the dent from the plurality of dents because of the offset, it may be erroneously recognized which is the current dent. The dent sheet is a sheet of about 2 cm square, and there are a plurality of small dots struck by the probe, and a plurality of dents are entered in the field of view of the camera. For example, there is a risk of misrecognizing which dent was hit with the exchanged probe, and wrong offset information is acquired. Further, since the probe comes into contact with a wrong place on the substrate, the reliability of the inspection is affected.

  It is an object of the present invention to provide a probe offset information acquisition method and a substrate inspection apparatus capable of preventing erroneous recognition of a probe dent position, which occurs when acquiring probe offset information as described above. To do.

  In order to solve the above-described problems, one aspect of the present invention provides an XY drive mechanism that enables a movable head mounted with a probe to move forward and backward on an XY plane, and a control device that controls the XY drive mechanism. The control device controls the XY drive mechanism to move the movable head to a predetermined XY coordinate position, and moves a probe that can be raised and lowered in the Z direction perpendicular to the XY plane to a predetermined Used in an XY substrate inspection apparatus provided with a means for inspecting by contacting a substrate to be inspected at a coordinate position, and providing a dent sheet in which a dent is formed by a descending probe in the operation area of the movable head. The apparatus captures a dent image formed on the dent sheet by the replaced probe with a camera mounted on the movable head, and obtains probe offset information from the image information of the dent. In the acquisition method, the control device exchanges a step of capturing an image of a dent sheet that has been dented in the previous offset information acquisition step with a camera, a step of forming a dent on the dent sheet with a probe after replacement, and a replacement. The difference between the acquired image of the dent sheet before and after the probe replacement, and the image position of the dent mark with the probe after replacement. And obtaining the offset position information of the probe.

  Another aspect of the present invention includes an XY drive mechanism that enables a movable head mounted with a probe to move forward and backward on an XY plane, and a control device that controls the XY drive mechanism. The XY drive mechanism is controlled to move the movable head to a predetermined XY position, and the probe that can be moved up and down in the Z-axis direction orthogonal to the XY plane is inspected at a predetermined coordinate position. The control device is provided with means for inspecting the target substrate in contact with the target substrate, and the control device is provided with means for acquiring the offset information of the probe position when the probe is replaced. The control device is provided in the head operating area, and the controller captures a dent image formed on the dent sheet by the probe after replacement with a camera mounted on the movable head, and determines the probe position from the image information of the dent. In the XY substrate inspection apparatus including means for acquiring offset information, the means for acquiring the offset information of the probe position is a means for capturing an image of the dent sheet that has been scribed in the previous offset information acquisition process with a camera. , Means for forming a new dent on the dent sheet with the replaced probe, means for taking an image of the dent sheet with the camera after the replacement, and images of the dent sheet before and after the replacement And a means for obtaining an offset information of the probe by extracting an image of the dent made by the probe after replacement.

  According to the present invention, since the offset information can be acquired by taking an image of the dent of the probe without error, no error occurs in the offset information. Further, since the operator does not make a difference, there is an effect that the offset information becomes uniform.

It is a figure explaining the control structure of the XY orthogonal biaxial drive mechanism of an XY board | substrate inspection apparatus. It is a top view explaining an offset acquisition board. It is explanatory drawing of the image in which several dents were formed in the dent sheet | seat sheet. It is a figure explaining the image processing of the last and this dent in this invention. It is a flowchart of the process which acquires the offset information in this invention.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a drive control configuration of an XY orthogonal two-axis drive mechanism of an XY substrate inspection apparatus according to an embodiment of the present invention for obtaining offset information of a probe. The hardware configuration of the XY board inspection apparatus in FIG. 1 is not different from the conventional one, and only the control configuration for obtaining offset information is different.

  The XY orthogonal two-axis drive mechanism of the XY substrate inspection apparatus used in the embodiment of the present invention is not different from the drive mechanism described in the conventional example. The XY orthogonal two-axis drive mechanism includes an X-axis drive unit 10 that drives in the X-axis direction that is long in the drawing, and a Y-axis drive unit 14 that drives in the Y-axis direction that is orthogonal to the X-axis and short in the drawing. And a control device 20. The X-axis drive unit 10 includes an X-axis ball screw 11 and an X-axis servo motor 12 that rotationally drives the X-axis ball screw 11. The Y-axis drive unit 14 includes a Y-axis ball screw 15 and a Y-axis servo motor 16 that rotationally drives the Y-axis ball screw. The Y-axis drive unit 14 is equipped with a movable head 17, and the movable head 17 includes a probe 18 and a camera 19.

Both the X-axis servo motor 12 and the Y-axis servo motor 16 are driven under the control of the control device 20, and the X-axis drive unit 10 moves the Y-axis drive unit 14 in the X-axis direction, and the Y-axis drive unit 14. Moves the movable head 17 in the Y-axis direction, and moves the movable head 17 to the XY coordinate position indicated by the control device 20.
The XY orthogonal two-axis drive mechanism of FIG. 1 includes a linear guide mechanism for both the X axis and the Y axis, but is not shown because it only shows the control mechanism.

  The movable head 17 is provided with a probe 18 that can move in a direction orthogonal to the XY plane (Z direction). During substrate inspection, the control device 20 controls the substrate to be inspected at a predetermined position (inspection point). ) To contact the substrate and inspect the substrate. In addition, a camera 19 is attached to the movable head 17, and an image of the dent sheet 23 can be taken in order to acquire offset information of the probe 18. Further, at the time of inspecting the substrate, it is possible to determine whether the probe 18 has moved to the designated position on the substrate to be inspected by acquiring an image of the position reached by the probe 18.

  Next, with reference to FIGS. 4 and 5, the acquisition of the offset information of the probe according to the embodiment of the present invention will be described. FIG. 4 is a diagram for explaining processing of a dent image according to this embodiment, and FIG. 5 is a flowchart for explaining an offset information acquisition operation of the probe according to this embodiment.

  When the substrate inspection is being performed, the probe replacement time comes and an instruction to that effect is given, and the operator replaces the probe with a new probe in accordance with the instruction (step S1). When the probe is exchanged, the operation proceeds to the probe offset information acquisition operation.

  When the operation proceeds to the probe offset information acquisition operation, first, the movable head 17 is moved to the dent position of the dent sheet 23 dent at the time of the previous offset information acquisition (step S2). And the image of the last dent is imaged with the camera 19 (step S3). If multiple offsets are acquired on the same dent sheet by acquiring offset information multiple times up to the previous dent, a dent image with multiple dent marks at different coordinates. Will be acquired. This image is the middle image in FIG.

  In addition, when the above-mentioned last impression sheet image is imaged, it is a case where the instruction | indication position for offset information acquisition becomes the area | region of the same impression sheet as last time. When instructing a dent on a different dent sheet, an image of the instructed dent sheet is taken. Actually, by inputting a coordinate instruction for obtaining offset information, the probe (movable head) moves onto the dent sheet, and an image of the dent sheet is acquired before making the dent. This image means the image of the dent sheet before the dent of the replaced probe.

  When an image of the previous dent is captured, the probe is lowered to make a dent on the dent sheet 23 (step S4). The dent of this time is not the same position as the position of the dent of the dent sheet until the previous time, but the dent is made at a coordinate position different from the previous position of the dent by the user setting. For example, a dent is made by setting a coordinate position shifted by several mm from the previous set value.

  And if a dent is struck by a probe, the camera 19 will be imaged with the dent of the dent sheet | seat 23 according to the position of a probe (step S5). The operator may operate to adjust the camera to the position of the probe, or may be automatically operated so that the probe position is automatically set by the actuator. The positional relationship between the camera and the probe is known, and the coordinate value is reflected in the detection of the offset information.

  The control device 20 compares the imaged dent image of this time with the image of the dent image remaining until the previous offset, and obtains a difference from the current dent image to the previous dent image. As a result, as shown in the image on the right of FIG. 4, the dent image up to the previous time is erased and only the image that was dented by the current offset information acquisition remains, so the position information of this dent is acquired as offset information (Step S6). Based on the position information (deviation from the target position coordinates) of the dent acquired in the current offset information acquisition process and the position information of the dent acquired in the previous offset information acquisition process, the deviation caused by the replacement of the probe this time The offset amount for compensation is calculated, and the offset compensation of the probe after replacement is performed.

  Note that if the previous dent image is to be recorded on the same dent sheet from which the previous offset information was acquired, an image obtained by imaging a new dent is stored and the probe is replaced. A difference from the dent image may be taken.

  As described above, even if there are a plurality of dents on the dent sheet, only the dent newly formed by the probe can be observed, so that accurate offset information can be acquired without making an erroneous dent. Further, since the dent image to be taken by the same method can be extracted regardless of the operator, the work and the offset information itself can be made uniform.

  The drive control of the movable head has been described with the XY orthogonal two-axis drive mechanism. However, since the movable head may be moved back and forth on the XY plane using an arm, the XY orthogonal 2 For example, an arm-type movable head moving mechanism may be used.

DESCRIPTION OF SYMBOLS 10 X-axis drive unit 11 X-axis ball screw 12 X-axis servo motor 14 Y-axis drive unit 15 Y-axis ball screw 16 Y-axis servo motor 17 Movable head 18 Probe 19 Camera 20 Control device 21 Stage 22 Offset acquisition board 23 Scoring sheet

Claims (2)

An XY drive mechanism that enables a movable head mounted with a probe to move back and forth on an XY plane; and a control device that controls the XY drive mechanism;
The control device controls the XY drive mechanism to move the movable head to a predetermined XY coordinate position and moves the probe that can be moved up and down in the Z direction orthogonal to the XY plane to a predetermined It is used in an XY board inspection apparatus provided with a means for inspecting by contacting a substrate to be inspected at a coordinate position,
A dent sheet in which a dent is formed by a descending probe is provided in the operation area of the movable head,
The controller captures a dent image formed on the dent sheet by the replaced probe with a camera mounted on the movable head, and obtains probe position offset information from the dent image information. In the probe offset information acquisition method,
The controller is
Capturing the image of the dent sheet that has been dented in the previous offset information acquisition process with the camera;
Forming a dent on the dent sheet with the probe after replacement; and
Capturing an image of the dent sheet that has been dented with the probe after the replacement with the camera;
Taking the difference between the images of the dent sheet before and after the acquired probe replacement, identifying the image position dented by the probe after the replacement, and acquiring the offset position information of the probe. To obtain the offset information of the probe. An XY drive mechanism that enables a movable head mounted with a probe to move back and forth on an XY plane; and a control device that controls the XY drive mechanism;
The control device controls the XY drive mechanism to move the movable head to a predetermined XY position, and allows the probe to move up and down in the Z-axis direction orthogonal to the XY plane. A means for inspecting the probe by contacting the substrate to be inspected at a predetermined coordinate position;
The control device comprises means for acquiring offset information of the probe position when the probe is replaced,
A dent sheet on which a dent is formed by the descending probe is provided in the operation area of the movable head,
The control device captures a dent image formed on the dent sheet by the probe after replacement with a camera mounted on a movable head, and obtains probe position offset information from the image information of the dent. In an XY board inspection apparatus comprising:
Means for obtaining the probe position offset information,
Means for taking an image of the dent sheet that was dented in the previous offset information acquisition step with the camera;
Means for forming a new dent on the dent sheet with the probe after replacement;
Means for capturing an image of a dent sheet formed by the probe after the replacement with the camera;
XY substrate inspection, comprising: means for taking a difference between images of the dent sheet before and after replacement, and extracting an image recorded by the probe after replacement to obtain offset information of the probe. apparatus.

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