JP6422819B2 - Image recognition apparatus and image recognition method - Google Patents

Description

  The present invention relates to an image recognition apparatus and an image recognition method.

  When manufacturing a semiconductor device, die bonding for mounting a semiconductor chip on a lead frame as a mounted member is performed. For this die bonding, a die bonder having a collet for adsorbing a chip is used (Patent Document 1 and Patent Document 2).

  As shown in FIG. 11, such a die bonder includes a supply unit 2 in which a semiconductor chip 1 to be picked up is arranged, a bonding arm 10 having a collet 3 that adsorbs the semiconductor chip 1 of the supply unit 2, and a supply unit. A recognition device 6 for observing the semiconductor chip 1 and a recognition device 12 for observing the island portion 5 of the lead frame 4 at the bonding position.

  The supply unit 2 includes a semiconductor wafer 8 mounted and supported on the wafer support device 7. The semiconductor wafer 8 is divided into a large number of semiconductor chips 1. The collet 3 is connected to a collet holder 9, and the collet 3 and the collet holder 9 constitute a bonding arm 10. The bonding arm 10 can be moved between the pickup position and the bonding position via the conveying means 11. The transport unit 11 can drive the bonding arm 10 in the X, Y, θ, and Z directions.

  Further, the collet 3 is vacuum-sucked through the suction holes opened in the lower end surface thereof, and the chip 1 is adsorbed on the lower end surface of the collet 3. If this vacuum suction (evacuation) is released, the chip 1 is detached from the collet 3.

  Next, a die bonding method using the die bonder apparatus shown in FIG. 11 will be described. First, the chip 1 to be picked up is observed by the recognition device 6 disposed above the supply unit 2, and the chip 1 is picked up by placing the collet 3 above the chip 1 to be picked up.

  Further, the island portion 5 of the lead frame 4 to be bonded is observed by the recognition device 12 disposed above the bonding position, and the collet 3 is moved onto the island portion 5 so that the chip is placed on the island portion 5. 1 is supplied.

  That is, the chip 1 positioned based on the observation of the recognition device 6 is picked up by the collet 3 of the bonding arm 10, and the island portion 5 of the lead frame (substrate) 4 conveyed to the lower part of the island recognition camera 22 is The camera 22 recognizes and measures the position. Then, feedback control is performed, the bonding arm 10 is driven, and the chip 1 is mounted on the island portion 5 at the measured position. For this reason, the collet 3 moves as indicated by an arrow A shown in FIG.

JP 2006-73631 A JP 2008-124382 A

  As shown in FIG. 10, the recognition devices 6 and 12 include a lens system 15 in which a lens is accommodated, a camera and an illumination unit (not shown), and observe through the lens system 15. For this reason, the lens system 15 is incorporated in a device such as a die bonder, and performs Z adjustment for adjusting the work distance of the lens and XY adjustment for adjusting the recognition position. As a lens used for such image recognition or the like, a telecentric lens having a small structural aberration is generally used. The telecentric lens is an optical system arranged so that the principal ray passes through the focal point, and is a lens in which the principal ray is parallel to the optical axis, that is, a lens having an angle of view of 0 °. The telecentric lens is a lens whose angle of view is close to 0 °, and the feature is that the size of the optical image of the subject at the imaging position does not affect the distance from the lens to the subject.

  In this case, it is necessary to adjust the three axes of the X axis, the Y axis, and the Z axis so that the optical axis L is orthogonal to the surface to be observed (target surface). However, even if the X axis, Y axis, and Z axis are adjusted, the optical axis L is decentered around the X axis as indicated by L1 and L2 in FIG. L may be eccentric about the Y axis, as indicated by L3 and L4 in FIG. That is, the optical path may be inclined with respect to the Z axis.

  If the optical path is inclined with respect to the Z axis as indicated by L1 and L2 in FIG. 10A and L3 and L4 in FIG. 10B, the lens light beam is not orthogonal to the target surface. Defocusing of the image occurs at different positions along the optical axis, resulting in a decrease in contrast and asymmetry on the image side. In addition, asymmetry of the magnification that varies depending on the object distance also occurs, and the telecentricity of the lens itself cannot be exhibited. For this reason, the position detection accuracy of the object is impaired.

  However, a configuration that can confirm orthogonality between the lens optical axis and the target surface has not been proposed. In addition, in order to make the lens optical axis and the target surface orthogonal, it is necessary to improve the component accuracy. In particular, when the lens is orthogonal with respect to the lens outer shape, the component accuracy becomes strict and the cost increases. In addition, since there is no compensation that the lens outer shape and the optical axis are parallel to each other, it causes variations in position detection accuracy of the object.

  In view of the above problems, the present invention can adjust the orthogonal state between the optical axis of the lens system and the target surface (observation surface) on various devices to be mounted with high accuracy, thereby improving the image recognition accuracy. An image recognition apparatus and an image recognition method are provided.

An image recognition apparatus according to the present invention includes an illumination unit, a camera, a lens system for image recognition, and an alignment mechanism that performs optical axis alignment of the X-axis and Y-axis lens systems , and the lens system is telecentric. An image recognition apparatus using a lens, wherein an Xθ adjustment unit that adjusts an optical axis of the lens system around an X axis, a Yθ adjustment unit that adjusts an optical axis of the lens system around a Y axis , An inclination detecting means for detecting an optical axis inclination around the X axis and an optical axis inclination around the Y axis of the optical axis of the lens system, and based on the inclination detecting means, the Xθ adjusting means and / or the Yθ adjusting means is provided. The tilt detection unit irradiates the object with illumination light from the diaphragm mechanism and the illumination unit through the diaphragm hole of the diaphragm mechanism and reflects the reflected light from the object. Light guide treatment to enter the camera through the aperture hole With the door, it is obtained by allowing the observation of the reflection of throttle hole on the camera image.

  According to the image recognition apparatus of the present invention, the Xθ adjustment means can adjust the optical axis of the lens system around the X axis, and the Yθ adjustment means can adjust the optical axis of the lens system around the Y axis. It can be performed. Therefore, even if the optical axis of the lens system is tilted around the X axis or the optical axis of the lens system is tilted around the Y axis, the tilts can be adjusted by each adjusting means.

  With this configuration, the alignment mechanism performs alignment of the X axis, Y axis, and Z axis of the lens system, and the Xθ inclination detection unit and / or the Yθ inclination detection unit performs Xθ inclination and Yθ inclination. When X is detected, optical axis calibration can be performed using the Xθ adjusting means and / or the Yθ adjusting means. Here, the telecentric lens is an optical system arranged so that the principal ray passes through the focal point, and is a lens in which the principal ray is parallel to the optical axis, that is, a lens having an angle of view of 0 °. The telecentric lens does not change the image size even if the position of the object (object) moves along the optical axis (the image size does not change even if the focus is shifted). Further, since the angle of view is 0 °, there is an advantage that image distortion due to parallax does not occur.

  With this configuration, the illumination light from the illumination unit is irradiated onto the object through the diaphragm hole of the diaphragm mechanism, and the reflected light from the object is incident on the camera through the diaphragm hole. When the optical axis of the lens system is not orthogonal to the object, it can be seen that the shape of the aperture hole is not formed (for example, a regular hexagon), and the optical axis is inclined.

  For this reason, it is possible to perform optical axis adjustment that overlaps the image of the aperture hole on the camera image using the Xθ adjusting means and / or the Yθ adjusting means. In this case, while confirming the camera image, the Xθ The inclination around the X axis and / or the inclination around the Y axis is adjusted by the adjusting means and / or the Yθ adjusting means.

  The aperture value of the aperture hole of the aperture mechanism is reduced, the illumination light from the illumination unit is irradiated onto the object with the light guide jig, and the reflected light from the object is incident on the camera through the light guide jig. The image can be confirmed so that it can be confirmed. By comprising in this way, an image confirmation operation | work can be performed, without performing the removal and attachment operation | work of the member used for optical axis calibration.

  It can be mounted on a device that performs image recognition, and the device can be a die bonder. That is, the present invention can be used for a recognition device for observing a semiconductor chip in a supply portion where a semiconductor chip to be picked up is arranged, or a recognition device for observing an island portion of a lead frame at a bonding position.

An image recognition method according to the present invention is an image recognition method for recognizing an image through a lens system of a telecentric lens by performing optical axis alignment of an X-axis / Y-axis lens system, and the optical axis of the lens system. The optical axis inclination around the X axis and the optical axis inclination around the Y axis are detected by the detecting means, and based on this detection, the adjustment of the optical axis of the lens system around the X axis and / or the optical axis of the lens system are detected. The detection means irradiates the object with illumination light from the diaphragm mechanism and the illumination unit through the diaphragm hole of the diaphragm mechanism and adjusts the optical axis around the Y axis. And a light guide jig for allowing the reflected light to enter the camera through the aperture hole, and the reflection of the aperture hole on the camera image can be observed.

  According to the image recognition method of the present invention, the X axis and the Y axis are aligned, the optical axis of the lens system is adjusted around the X axis and / or the optical axis of the lens system is adjusted around the Y axis, Optical axis calibration can be performed.

  In the present invention, the optical axis calibration can be performed by adjusting the optical axis of the lens system around the X axis and / or adjusting the optical axis of the lens system around the Y axis. It can be set in a state orthogonal to the object, and highly accurate image recognition (position detection) of the object can be performed.

  When using a telecentric lens in the lens system, the asymmetry of the magnification that changes with the object distance does not occur, the telecentricity performance of the lens itself can be exhibited, defocusing at different positions is suppressed, and symmetry is maintained. The In addition, since the magnification changing according to the object distance is also maintained symmetrically, the original position detection performance of the image recognition apparatus can be exhibited.

  If a diaphragm mechanism is used for the tilt detection means, the tilt of the optical axis can be easily detected and the optical axis calibration can be performed stably. In addition, a known and publicly used diaphragm mechanism can also be used, and cost reduction can be achieved. In addition, in the case of adjusting the optical axis so as to overlap the image of the aperture hole on the camera image, the tilt around the X axis and / or the tilt around the Y axis can be adjusted while checking the camera image. And can be adjusted with high accuracy.

  Also, in the case where the image recognition operation can be performed by reducing the aperture value of the aperture mechanism, the image recognition device is removed from the die bonder after the optical axis calibration, or the image recognition device is removed from the die bonder before the optical axis calibration. Therefore, the work efficiency can be improved without requiring the work of attaching to the head. Moreover, as an adjustment method, it is possible to perform adjustment while observing the image of the camera, the operation is easy, the adjustment time can be shortened, and further, variation in adjustment can be suppressed. .

It is a principal part simplification figure of the image recognition apparatus which shows embodiment of this invention. It is a simplified diagram of an alignment mechanism. The Xθ adjusting means and the Yθ adjusting means are shown, wherein (a) is a simplified view of the adjustment state of the Xθ adjustment means, and (b) is a simplified view of the adjustment state of the Yθ adjustment means. The Xθ adjusting means and the Yθ adjusting means are shown, wherein (a) is a simplified plan view of the adjustment state of the Xθ adjustment means, and (b) is a simplified plan view of the adjustment state of the Yθ adjustment means. It is a timing chart figure of the image recognition method showing the embodiment of the present invention. It is a timing chart figure of the other image recognition method of this invention. It is a timing chart figure of another image recognition method of the present invention. It is a simplified diagram showing the relationship between the optical axis and the aperture mechanism. The optical axis calibration results are shown, wherein (a) is a simplified diagram with a tilt of 0.05 °, and (b) is a simplified diagram with a tilt of 0.01 °. The relationship between the optical axis of a lens system and an object is shown, (a) is an explanatory view when the optical axis is tilted around the X axis, and (b) is an explanation when the optical axis is tilted around the Y axis. FIG. It is a perspective view of a die bonder.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 shows an image recognition apparatus according to the present invention. The image recognition apparatus includes a lens system 20 in which a lens is housed, a light guide jig 21 attached to the lens system 20, a camera 22, and an illumination unit. 23. A telecentric lens is used as the lens. Here, the telecentric lens is an optical system arranged so that the principal ray passes through the focal point, and is a lens in which the principal ray is parallel to the optical axis, that is, a lens having an angle of view of 0 °. This image recognition apparatus is used for the image recognition apparatus 6 or the image recognition apparatus 12 of the die bonder shown in FIG.

  The light guide jig 21 forms an optical axis L0 orthogonal to the optical axis L of the lens system 20, and the camera 22 is disposed on the optical axis L0 line. In this case, the light guide jig 21 in this case includes a pair of half mirrors 25 and 26 and a lens 27 disposed between the half mirrors 25 and 26.

  The camera 22 can be a CMOS type or CCD type camera. Moreover, although LED illumination is preferable as an illumination part, light sources, such as a halogen light source, can also be used.

This image confirmation apparatus includes an inclination detecting means 30 for detecting an optical axis inclination around the X axis and an optical axis inclination around the Y axis of the optical axis L of the lens system 20, and an X axis around the optical axis L of the lens system. And an Xθ adjusting means 32 for adjusting around the Y axis of the optical axis of the lens system.

  The tilt detection means 30 can be composed of a diaphragm mechanism 33 disposed on the optical axis L of the lens system, the light guide jig 21, and the camera 22. The aperture mechanism 33 controls the light beam passing through the lens, and combines a plurality of (6 to 9) small wing-like plates to form a shape close to a circle (such as a hexagon). When the aperture value is increased, the circle is narrowed down.

  That is, the light guide jig 21 irradiates the object W with the illumination light from the illumination unit 23 through the aperture hole H of the aperture mechanism 33 and the reflected light from the object W through the aperture hole H with the camera 22. Can be incident. Then, it is possible to observe the reflection of the aperture hole H on the camera image.

  As shown in FIGS. 3 and 4, the Xθ adjusting means 31 includes a frame body 35 that surrounds the lens system 20, shaft portions 36 and 36 disposed on the X axis, and an operation attached to the frame body side. 3 is provided with a bolt screw (not shown) for screwing, and by pushing and retracting the bolt screw, the pressing surface portion (not shown) formed on the lens system 20 is pressed, and the optical axis L of the lens 20 is changed to that shown in FIG. As shown by La and Lb, it can be swung around the X axis.

  Further, as shown in FIGS. 3 and 4, the Yθ adjusting means 32 is attached to the frame body 40 surrounding the lens system 20, shaft portions 41 and 41 disposed on the X axis, and the frame body side. 3 and includes a bolt screw (not shown) for operation, and by pushing and retracting the bolt screw, a pressing surface portion (not shown) formed on the lens system 20 is pressed, and the optical axis L of the lens system 20 is set as shown in FIG. As indicated by Lc and Ld in (b), it can be swung around the Y axis.

  By the way, the lens system 20 of the image recognition apparatus can adjust the optical axes of the three axes of the X axis, the Y axis, and the Z axis that are orthogonal to each other via an alignment mechanism 45 as shown in FIG. The XYZ alignment mechanism 45 includes, for example, an X stage 46 that drives in the X axis direction, a Y stage 47 that drives in the Y axis direction, and a Z stage 48 that drives in the Z axis direction.

  Next, with the image recognition apparatus configured as described above, an image confirmation method for the object W will be described with reference to the flowchart of FIG. First, the lens system 20 is placed on the object W via the alignment mechanism 45 (step S1). Next, the illumination system is irradiated with the illumination light from the light guide jig 21. That is, the illumination light from the illumination unit 23 is irradiated to the object W through the light guide jig 21 and the aperture hole H of the aperture mechanism 33. When irradiated in this manner, the light is reflected by the object W and can enter the camera 22 through the aperture hole H.

  And it transfers to step S2 and it is judged whether the optical axis L has an inclination. If the optical axis L is inclined, the D1 overlaps with the aperture H on the camera image S as shown in FIG. That is, if the aperture hole H is a regular hexagon, the aperture hole shape on the camera screen S is not positive. For this reason, when there is an eccentricity (tilt) around the X axis, the Xθ adjustment means 31 adjusts the inclination around the X axis, and when there is an eccentricity (tilt) around the Y axis, the Yθ adjustment means 32 adjusts the Y axis. The inclination of the circumference will be adjusted. If it is determined in step S2 that there is no inclination, the adjustment operation is terminated.

  Next, it is determined whether or not there is an eccentricity (tilt) around the X axis (step S3). If there is an inclination around the X axis, the process proceeds to step S4, where the Xθ adjustment means 31 adjusts the inclination around the X axis. If there is no inclination around the X axis in step S3, the process proceeds to step S5. Further, the process proceeds to step S5 even after step S4 ends. The adjustment of the inclination around the X axis is performed by manually adjusting the Xθ adjustment means 31 while observing the image of the camera 22.

  In step S5, it is determined whether or not there is an eccentricity (tilt) around the Y axis. If there is an eccentricity (inclination) around the Y axis, the process proceeds to step S6 and the Yθ adjustment means 32 adjusts the inclination around the Y axis. Thereby, the inclination determined to be step S2 is corrected. If there is no eccentricity (inclination) around the Y axis in step S5, there is no inclination around the X axis at the time of shifting to step S5, so that the inclination is corrected. Further, the tilt around the Y axis is also adjusted manually while observing the image of the camera 22.

  In FIG. 6, steps S7 to S8 are the same as steps S1 to S2 in FIG. If it is determined in step S8 that there is an inclination, the process proceeds to step S9 to determine whether or not there is an eccentricity (inclination) around the Y axis. If there is an inclination around the Y axis, the process proceeds to step S10, and the Yθ adjusting means 32 adjusts the inclination around the Y axis. If there is no inclination around the Y-axis in step S9, the process proceeds to step S11. Further, the process proceeds to step S11 even after step S10 is completed.

  In step S11, it is determined whether or not there is an eccentricity (tilt) around the X axis. If there is an eccentricity (tilt) around the X axis, the process proceeds to step S12 and the tilt around the X axis is adjusted by the Xθ adjustment means 31. Thereby, the inclination determined to be step S8 is corrected. If there is no eccentricity (inclination) around the X axis in step S11, there is no inclination around the Y axis at the time of transition to step S11, so the inclination is corrected.

  In FIG. 7, the adjustment of the inclination around the Y axis and the adjustment around the X axis are performed simultaneously. Steps S13 to S14 are the same as steps S1 to S2 in FIG. If it is determined in step S14 that there is an inclination, the process proceeds to step S15 to adjust the inclination about the X axis and the Y axis. To adjust the inclination around the X axis and the Y axis, the Xθ adjusting means 31 and the Yθ adjusting means 32 are manually adjusted while observing the image of the camera 22.

  10A and 10B show the optical axis calibration results, where FIG. 10A shows the case where the inclination is 0.05 °, and FIG. 10B shows the case where the inclination is 0.010 °. In order to adjust to the inclination of 0.05 ° or less, the plane dimension inclined by 0.05 ° with respect to the WD 163 mm of the lens is 142 μm. Here, WD refers to the distance from the tip of the lens to the object when the object W is in focus.

  As described above, when the calibration operation of the inclination of the optical axis L is completed, the aperture value of the aperture mechanism 33 is decreased to increase the aperture. In this state, the die bonder image recognition device 6 shown in FIG. 11 observes the chip 1 to be picked up by the recognition device 6. In the die bonder image recognition device 12 shown in FIG. 9, the island portion 5 of the lead frame 4 is observed at the bonding position.

  In the present invention, the optical axis calibration can be performed by adjusting the optical axis L of the lens system 20 around the X axis and / or adjusting the optical axis L of the lens system 20 around the Y axis. The optical axis L of the object W can be set in a state orthogonal to the object W, and high-accuracy image recognition (position detection) of the object W can be performed.

  Since a telecentric lens is used for the lens system 20, the asymmetry of the magnification that varies depending on the object distance does not occur, the telecentricity performance of the lens itself can be exhibited, defocusing at different positions is suppressed, and symmetry is maintained. Is done. In addition, since the magnification changing according to the object distance is also maintained symmetrically, the original position detection performance of the image recognition apparatus can be exhibited.

  Further, if the diaphragm mechanism 33 is used in the tilt detection means 30, the tilt of the optical axis L can be easily detected and the optical axis calibration can be performed stably. In addition, a known and publicly available diaphragm mechanism 33 can be used, and the cost can be reduced.

  Further, the image recognition operation can be performed by reducing the aperture value of the aperture mechanism 33. That is, it is not necessary to remove the image recognition device from the die bonder after the optical axis calibration, or to attach the image recognition device to the die bonder before the optical axis calibration, and work efficiency can be improved. Moreover, as an adjustment method, it is possible to make an adjustment while observing the image of the camera 22, the operation is easy, the adjustment time can be shortened, and further, variation in adjustment can be suppressed. is there.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the image recognition apparatus is not limited to a die bonder. It can also be used for various devices that require the above-mentioned, that is, general machines, electric machines, transport machines, and the like. As the inclination adjustment in this image recognition apparatus, it is possible to correspond to an inclination within a range of ± 1.5 ° with respect to the vertical line.

  The light guide jig 21 is not limited to the example shown in the figure, and the illumination light from the illumination unit 23 can be irradiated to the object W through the aperture hole H of the aperture mechanism 33 provided in the lens system 20. Any type of lens and the number of lenses can be set as long as the reflected light can enter the camera 22 through the aperture hole H of the aperture mechanism 33. In the embodiment, the illumination light source used for the tilt inspection and the illumination light source used for the image recognition use the common illumination unit 23. However, different light sources may be used. . Furthermore, a telecentric lens is optimal as a lens used in the lens system 20.

20 Lens system 21 Light guide jig 22 Camera 23 Illumination unit 30 Tilt detection means 31 Xθ adjustment means 32 Yθ adjustment means 33 Aperture mechanism 45 XYZ positioning mechanism H Aperture hole W Object

Claims (6)

An image recognition apparatus comprising an illumination unit, a camera, a lens system for recognizing an image, and an alignment mechanism for aligning the optical axes of the X-axis and Y-axis lens systems, and using a telecentric lens for the lens system There,
Xθ adjusting means for adjusting the optical axis of the lens system around the X axis, Yθ adjusting means for adjusting the optical axis of the lens system around the Y axis , and light around the X axis of the optical axis of the lens system An inclination detecting means for detecting an axis inclination and an optical axis inclination around the Y axis, and based on the inclination detecting means, optical axis calibration is performed using the Xθ adjusting means and / or the Yθ adjusting means, and The tilt detection unit irradiates the object with illumination light from the diaphragm mechanism and the illumination unit through the diaphragm hole of the diaphragm mechanism, and causes reflected light from the object to enter the camera through the diaphragm hole. An image recognition apparatus comprising: a light guide jig, wherein the image of the aperture hole can be observed on the camera image . 2. The image recognition apparatus according to claim 1 , wherein an optical axis adjustment is performed to superimpose an image of an aperture hole on the camera image using the Xθ adjustment unit and / or the Yθ adjustment unit . The aperture value of the aperture hole of the aperture mechanism is reduced, the illumination light from the illumination unit is irradiated onto the object with the light guide jig, and the reflected light from the object is incident on the camera through the light guide jig. The image recognition apparatus according to claim 1, wherein the image can be confirmed . The image recognition apparatus according to claim 1, wherein the image recognition apparatus is mounted on an apparatus that performs image recognition. The image recognition apparatus according to claim 4 , wherein the apparatus that performs image recognition is a die bonder . An image recognition method for recognizing an image through a lens system of a telecentric lens by performing optical axis alignment of a lens system of an X axis and a Y axis,
An optical axis tilt around the X axis and an optical axis tilt around the Y axis of the lens system are detected by a detecting means, and based on this detection, adjustment of the optical axis of the lens system around the X axis and / or Alternatively, the optical axis calibration is performed by adjusting the optical axis of the lens system around the Y axis, and the detecting means applies the diaphragm mechanism and the illumination light from the illumination unit to the object through the diaphragm hole of the diaphragm mechanism. A light guide jig that irradiates and reflects reflected light from an object to the camera through the aperture hole, and enables an image of the aperture hole to be observed on the camera image. Recognition method.